US20180176900A1

US20180176900A1 - Systems and Methods for Determining Air Interface Configuration

Info

Publication number: US20180176900A1
Application number: US15/897,846
Authority: US
Inventors: Lu Rong; Jianglei Ma; Peiying Zhu; Wen Tong; Kelvin Kar Kin Au
Original assignee: Huawei Technologies Co Ltd
Current assignee: Huawei Technologies Co Ltd
Priority date: 2015-12-08
Filing date: 2018-02-15
Publication date: 2018-06-21
Also published as: EP3378197B1; KR102113018B1; CN108370587A; US20180184413A1; WO2017097225A1; US20170164349A1; CN108353008A; CN112333001B; CN108370576A; EP3378251A4; JP6626204B2; BR112018011546A2; CN108370530B; WO2017098441A1; EP3378263A4; EP3378251A1; JP2018538751A; WO2017097227A1; US20180184415A1; CN112333001A

Abstract

A method and system of allocating resources in a Radio Access Network that includes associating each of a plurality of services with a slice that is allocated a unique set of network resources and transmitting information in the Radio Access Network for at least one of the services using the slice associated with the at least one service.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of PCT Application No. PCT/IB2016/057454, filed Dec. 8, 2016, which claims priority to U.S. patent application Ser. No. 15/356,124 filed Nov. 18, 2016 and to U.S. Provisional Patent Application No. 62/264,629 filed Dec. 8, 2015, all of which applications are hereby incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to slicing of Radio Access Networks and creating end to end network slices in wireless networks.

BACKGROUND

In designing mobile networks, an architecture has arisen in which the network can be divided into a Core Network (CN) and a Radio Access Network (RAN). The RAN provides wireless communication channels to User Equipment (UE), while the CN is typically comprises of nodes and functions making use of fixed links. In the RAN, fronthaul and backhaul connections often rely on wired connections, although some wireless connections (typically between fixed points) are present. The RAN has different requirements and issues to address than the CN.
With planning for next generation networks, and researching techniques that can enable such networks, network slicing has drawn attention for the benefits that it can provide in the CN. When combined with such techniques as Network Function Virtualization (NFV) and Software Defined Networking (SDN), network slicing can allow for the creation of Virtual Networks (VNs) atop a general pool of compute, storage and communications resources. These VNs can be designed with control over in-network topology, and can be designed with traffic and resource isolation so that traffic and processing within one slice is isolated from traffic and processing demands in another slice. By creating network slices, isolated networks can be created with characteristics and parameters specifically suited to the needs for the traffic flows intended for the slice. This allows for a single pool of resources to be divided up to service very specific and disparate needs, without requiring that each slice be able to support the demands of the services and devices supported by other slices. Those skilled in the art will appreciate that a CN that has been sliced, may appear to the RAN as a plurality of core networks, or there may be a common interface, with each slice identified by a slice identifier. It should also be understood that while a slice may be tailored to the traffic patterns of the flows that it is intended to carry, there may be multiple services (typically with similar requirements) carried within each slice. Each of these services is typically differentiated by a service identifier.
In creating a sliced core network, it should be understood that typically the resource pool that is being drawn upon for slice resources is somewhat static. The compute resources of a data center are not considered to be dynamic on a short term basis. The bandwidth provided by a communications link between two data centers, or between two functions instantiated within a single data center does not typically have dynamic characteristics.
The topic of slicing within a Radio Access Network, has arisen in some discussions. RAN slicing poses problems not encountered with slicing in the CN. Issues associated with dynamic channel quality on the radio link to the UE, provision of isolation for transmissions over a common broadcast transmission medium, and how RAN and CN slices interact, have to be addressed to usefully enable Ran slicing in mobile wireless networks.
In Third Generation and Fourth Generation (3G/4G) network architecture, a base station, base transceiver station, NodeB, and evolved NodeB (eNodeB) have been the terms used to refer to the wireless interface to the network. In the following, a generic Access Point is used to denote the wireless edge node of the network. An Access Point will be understood to be any of a Transmission Point (TP), a Receive Point (RP) and a Transmit/Receive Point (TRP). It will be understood that the term AP can be understood to include the above mentioned nodes, as well as their successor nodes, but is not necessarily restricted to them.
Through the use of SDN and NFV, functional nodes can be created at various points in the network and access to the functional nodes can be restricted to sets of devices, such as UEs. This allows what has been referred to as Network Slicing in which a series of virtual network slices can be created to serve the needs of different virtual networks. Traffic carried by the different slices can be isolated from the traffic of other slices, which allows for both data security and easing of network planning decisions.
Slicing has been a used in core networks due to the ease with which virtualized resources can be allocated, and the manner in which traffic can be isolated. In a Radio Access Network, all traffic is transmitted over a common resource which has made traffic isolation effectively impossible. The benefits of network slicing in the Radio Access Network are numerous, but the technical obstacles to designing and implementing an architecture have resulted in a lack of network slicing at the radio edge.

SUMMARY

According to one aspect of the present invention, there is provided a method comprising: selecting, by the controller in an access network, a first group access points (APs) as a member of a first cell associated with a first RAN slice, sending, by the controller, a first message to the first group APs, wherein the first message indicates information of the first cell; selecting, by the controller, a second group APs as a member of a second cell associated with a second RAN slice; sending, by the controller, a second message to the second group APs, wherein the second message indicates information of the second cell.
In some embodiments, before the sending step, further comprising: selecting, by the controller, the first group APs and the second group APs to group the different cell to provide one or more different RAN slices based on mobility of the UE.
In some embodiments, before the sending step, further comprising: obtaining, by the controller, the information of the first and second cell associated with a randomization sequence or scheme for a respective cell.
In some embodiments, each randomization sequence or scheme is associated with a respective randomization ID.
In some embodiments, the randomization ID is a cell ID, the method further comprises: randomizing, by the RAN controller, a bit sequence using the cell ID; performing, by the RAN controller, bitwise exclusive or to the bit sequence before modulation with a pseudo-random sequence generated or associated with the cell ID.
In some embodiments, the method further comprises maintaining, by the controller, a mapping relationship between a cell ID for each cell and a synchronization sequence.
In some embodiments, the first and second message comprises one or a combination of: cell Identifier (ID), slice ID, service ID, access point set ID, or any other ID to identify the cell, a list of the access points of one of the cells.
In some embodiments, the first slice and the second slice are any one of an eMBB services, V2X services, mMTC services; e and URLLC services.
In some embodiments, the first cell and the second cell are hyper cell, and the hyper cell provides a wireless access for a coverage area with non-cellular grid among the APs; the coverage area servers a user equipment (UE) moving freely in the coverage area.
According to another aspect of the present invention, there is provided a controller in an access network comprising a plurality of access points (APs), comprising: a processor; and a non-transient memory for storing instructions that when executed by the processor cause to: select a first group access points (APs) as a member of a first cell associated with a first RAN slice, and send a first message to the first group APs, wherein the first message indicates information of the first cell; select a second group APs as a member of a second cell associated with a second RAN slice; and send a second message to the second group APs, wherein the second message indicates information of the second cell.
In some embodiments, the non-transient memory further stores instructions to select the first group APs and the second group APs to group different cell to provide one or more different RAN slices based on mobility of the UE.
In some embodiments, the non-transient memory further stores instructions to obtain the information of the first and second cell associated with a randomization sequence or scheme for a respective cell.
In some embodiments, each randomization sequence or scheme is associated with a respective randomization ID.
In some embodiments, the non-transient memory further stores instructions to maintain a mapping relationship between a cell ID for each cell and a synchronization sequence.
In some embodiments, the first and second message comprises one or a combination of: cell Identifier (ID), slice ID, service ID, access point set ID, or any other ID to identify the cell, a list of the access points of one of the cells.
According to a further aspect of the present invention, there is provided a method comprising, receiving, by an access point (AP), a message from a controller, wherein the message indicates information of a cell associated with a RAN slice; receiving, by the AP, data from a user equipment (UE) with a set of transmission parameters associated with the RAN slice.
In some embodiments, the information of the cell is associated with a randomization sequence or scheme for a respective cell.
In some embodiments, each randomization sequence or scheme is associated with a respective randomization ID.
In some embodiments, the message comprises one or a combination of: cell Identifier (ID), slice ID, service ID, access point set ID, or any other ID to identify the cell, a list of the access points of one of the cells.
In some embodiments, the method further comprises: sending, by the AP, synchronization information to the UE, wherein the synchronization information comprises a synchronization sequence, and the synchronization sequence is associated with the randomization sequence.
In some embodiments, the AP is a member of two or more cells providing same or different RAN slice.
In some embodiments, the further method comprises: communicating, by the AP, the uplink and downlink transmissions to the UE using a different randomization sequence for uplink and downlink transmissions.
In some embodiments, the randomization sequence for downlink transmission has a mapping relationship with the synchronization sequence, and the randomization sequence for downlink transmission has a pre-defined relationship with the uplink randomization sequence.
According to yet another aspect of the present invention, there is provide a network access point (AP), comprising: a processor; and a non-transient memory for storing instructions that when executed by the processor cause to: receive a message from a controller, wherein the message indicates information of a cell associated with a RAN slice; receive data from a user equipment (UE) with a set of transmission parameters associated with the RAN slice.
In some embodiments, the information of the cell is associated with a randomization sequence or scheme for a respective cell.
In some embodiments, each randomization sequence or scheme is associated with a respective randomization ID.
In some embodiments, the message comprises one or a combination of: cell Identifier (ID), slice ID, service ID, access point set ID, or any other ID to identify the cell, a list of the access points of one of the cells.
In some embodiments, the non-transient memory further stores instructions to send synchronization information to the UE, wherein the synchronization information comprises a synchronization sequence, and the synchronization sequence is associated with the randomization sequence.
According to still another embodiments of the present invention, there is provided a method in a user equipment (UE) comprising: receiving, by the UE, a synchronization information from an access point (AP), obtaining, by the UE, a cell ID of a cell associated with a RAN slice; sending, by the UE, data to the AP with a set of transmission parameters associated with the RAN slice, wherein the set of transmission parameters is one of the multiple sets of transmission parameters associated with multiple RAN slices.
In some embodiments, the method further comprises: decoding successfully, by the UE, a synchronization sequence from candidate synchronization signals; obtaining, by the UE, the cell ID based on a pre-defined relationship between the cell ID and the synchronization sequence.
In some embodiments, the synchronization sequence is associated with a randomization sequence, and the randomization sequence is associated with a respective cell ID.
In some embodiments, the method further comprises: receiving, by the UE, information from two APs serving to same or different RAN slice.
In some embodiments, the cell is hyper cell, and the hyper cell provides a wireless access for a coverage area with non-cellular grid among the APs; the coverage area servers a user equipment (UE) moving freely in the coverage area.
In some embodiments, one of the multiple RAN slices is any one of eMBB services, V2X services, mMTC services or URLLC services.
According to another aspect of the present invention, there is provided a User Equipment (UE) comprising: a processor; and a non-transient memory for storing instructions that when executed by the processor cause to: receive a synchronization information from an access point (AP); obtain a cell ID of a cell associated with a RAN slice; send data to the AP with a set of transmission parameter associated with the RAN slice, wherein the set of transmission parameters is one of the multiple sets of transmission parameter associated with multiple RAN slices.
In some embodiments, the non-transient memory further stores instructions to decode successfully a synchronization sequence from candidate synchronization signals; and obtain the cell ID based on a pre-defined relationship between the cell ID and the synchronization sequence.
In some embodiments, the synchronization sequence is associated with a randomization sequence, and the randomization sequence is associated with a respective cell ID.
In some embodiments, the non-transient memory further stores instructions to receive information from two APs serving to same or different RAN slice.
In some embodiments, the cell is a hyper cell, and the hyper cell provides a wireless access for a coverage area with non-cellular grid among the APs; the coverage area servers a user equipment (UE) moving freely in the coverage area.
In some embodiments, one of the multiple RAN slices is any one of eMBB services, V2X services, mMTC services or URLLC services.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawing, in which:

FIG. 1 is a schematic diagram of an example communications system suitable for implementing various examples described in the present disclosure;

FIG. 2 is a schematic diagram illustrating an example set of parameters that are defined by a RAN slice manager for a service specific RAN slice instance according to example embodiments;

FIG. 3 is a schematic diagram illustrating an example of slice based service isolation in a RAN;

FIG. 4 is a schematic diagram illustrating dynamic slice allocations for different services on a common carrier according to example embodiments;

FIG. 5 is a schematic diagram illustrating a further example of slice based service isolation in a RAN;

FIG. 6 is a schematic diagram illustrating a UE connecting to multiple slices over different access technologies;

FIG. 7 is a schematic diagram, illustrating service customized virtual networks implemented using slices according to example embodiments;

FIG. 8 is a schematic diagram of an example processing system suitable for implementing various examples described in the present disclosure;

FIG. 9 is an illustration of an architecture for routing traffic from a Core Network Slice to a RAN slice in accordance with disclosed embodiments;

FIG. 10 is a flow chart illustrating a method for routing downlink traffic received from a core network slice to an AP in accordance with disclosed embodiments;

FIG. 11 is a flow chart illustrating a method for execution by an access point in accordance with disclosed embodiments;

FIG. 12 is an illustration of an architecture, similar to that of FIG. 9, for routing traffic from a core network slice to a RAN slice in accordance with disclosed embodiments; and

FIG. 13 is a flow chart illustrating a method for execution by a network controller in accordance with disclosed embodiments.

FIG. 14 is a diagram illustrating a hyper cells;

FIG. 15A is a diagram illustrating a radio access system based on hyper cells;

FIG. 15B is diagram of the network of FIG. 14A in which the TRPs are arranged in two hyper cells;

FIG. 15C is diagram of the network of FIG. 14A in which some of the TRPs are arranged in a third hyper cell;

FIG. 16 is a diagram showing how the TRPs serving a UE within a hyper cell can change with mobility of the UE;

FIG. 17 is a diagram showing how a TRP can be part of multiple hyper cells;

FIG. 18 is a diagram showing how a UE may be involved with multiple hyper cells for different services;

FIG. 19 is a diagram showing how a UE may be involved with different hyper cells for uplink and downlink communications;

FIGS. 20,21 and 22 are examples of different SYNC channel configurations;

FIG. 23 is a block diagram of an example of a hyper cell manager;

FIG. 24 is a block diagram of an example processing system for implementing one or more of the embodiments described herein; and

FIG. 25 is a flow chart illustrating a method for execution by a network system in accordance with disclosed embodiments.

DETAILED DESCRIPTION OF ILLUSTRATIVE EMBODIMENTS

Software Defined Networking (SDN) and Network Function Virtualization (NFV) have been used to enable network slicing in a physical core network. Network slicing involves allocating resources, such as compute, storage, and connectivity resources, to create otherwise isolated virtual networks. From the perspective of a network entity inside a slice, the slice is a distinct and contained network. Traffic carried on a first slice is invisible to a second slice, as are any processing demands within the first slice. In addition to isolating networks from each other, slicing allows for each slice to be created with a different network configuration. Thus, a first slice can be created with network functions that can respond with very low latency, while a second slice can be created with very high throughput. These two slices can have different characteristics, allowing for the creation of different slices to service the needs of specific services. A network slice is a dedicated logical (also referred to as virtual) network with service specific functionalities, and can be hosted on a common infrastructure with other slices. The service specific functionalities associated with a network slice can, for example, govern geographical coverage areas, capacity, speed, latency, robustness, security and availability. Traditionally, network slicing has been limited to the core network, in view of the difficulties in implementing slicing in a Radio Access Network (RAN). However example embodiments will now be described for implementing RAN slicing. In at least some examples, RAN slicing and network core slicing are coordinated to provide end-to-end slicing that can be used to provide service-specific network slices extending across the entire core network and RAN communications infrastructure.
Radio resources allocated to a RAN are typically a set of wireless network rights granted to a network operator which may include for example one or more specified radio frequency bandwidths within one or more geographic regions. A network operator typically enters into service level agreements (SLAs) with customers that specify the level of service that the network operator must provide. Services that are supported by a network operator can fall within a range of categories, including for example: basic mobile broadband (MBB) communications such as bi-directional voice and video communications; messaging; streaming media content delivery; ultra-reliable low latency (URLL) communications; micro Machine Type Communications (μMTC); and massive Machine Type Communications (mMTC). Each of these categories could include multiple types of services—for example intelligent traffic systems and eHealth services could both be categorized as types of URLL services. In some examples, a network slice may be assigned for a service for a group of customers (for example smart phone subscribers in the case of mobile broadband), and in some examples a network slice may be assigned for a single customer (for example, an organization that is providing intelligent traffic systems).
According to an example aspect, the present disclosure describes methods and systems of allocating resources in a radio access network (RAN) that includes associating each of a plurality of services with a slice that is allocated a unique set of network resources, and transmitting information in the RAN for at least one of the services using the slice associated with the at least one service.
According to a further aspect is a method for execution by an access point (AP) within a radio access network (RAN). The method includes receiving data for transmission to a User Equipment (UE), and wirelessly transmitting the received data to the UE using a set of transmission parameters associated with a RAN slice associated with the received data. In some example embodiments, the RAN slice associated with the received data is selected from a set of RAN slices supported by the AP. Furthermore, the RAN slice may be selected in accordance with a RAN slice identifier associated with the received data. In some configurations, the transmission parameters are selected in accordance with the selected RAN slice. In some embodiments, the set of transmission parameters are selected in accordance with an address of a gateway between the RAN and a core network. In some embodiments, the set of transmission parameters are selected in accordance with one of a core network identifier, a core network slice identifier and a service identifier associated with the received data. In some examples, at least one parameter in the set of transmission parameters is selected from a list comprising: radio frequency/time resources; a radio access technology; a transmission waveform; a frame length; and a numerology.
According to a further aspect, there is provided a network access point (AP) for transmitting data to a User Equipment (UE) over a radio channel in a radio access network (RAN). The AP includes a network interface for receiving data from a radio access network; a wireless network interface for transmitting data to the UE; a processor; and a non-transient memory for storing instructions. The instructions, when executed by the processor cause the network access point to: transmit data to the UE over the wireless network interface using a set of transmission parameters associated with a RAN slice, in response to receipt of the data for transmission to the UE over the network interface. In some example embodiments, the non-transient memory further stores instructions to select the transmission parameters in accordance with an address of a gateway from which the data is received. In some example embodiments, the non-transient memory further stores instructions to select at least one transmission parameter in the set in accordance with a RAN slice identifier associated with the data. In some configurations, the non-transient memory further stores instructions to select at least one transmission parameter in the set in accordance with one of a core network identifier, a core network slice identifier and a service identifier associated with the data. In some examples, at least one parameter is the set of transmission parameters is selected from a list comprising: radio frequency/time resources; a radio access technology; a transmission waveform; a frame length; and a numerology.
According to another aspect is a method for execution by a routing function in a radio access network (RAN), which includes receiving data traffic from a core network destined for a User Equipment (UE), and transmitting the received data traffic to a transmission point within a selected RAN slice associated with the received data traffic. In some configurations, the RAN slice associated with the received data traffic is selected in accordance with one of: an identifier associated with the core network; an identifier associated with a slice of the core network associated with the received data; and a service identifier associated with the received data. In some examples, the identifier associated with one of the core network and the slice of the core network is one of an address of a core network gateway function and a tunnel identifier. In various examples, receiving the data traffic includes one or more of receiving the data traffic from a gateway function within the core network and/or receiving the data traffic from a core network slice that the RAN slice can be pre-associated with. In some examples, the transmission point within the RAN slice is selected in accordance with information about the location of the UE with respect to the network topology. In some example embodiments, the method includes selecting a transmission point uniquely associated with the UE, and determining a set of constituent access points associated with the transmission point; wherein transmitting the received data comprises transmitting the received data to the set of constituent access points. In some examples, the step of transmitting includes modifying the received data to include a RAN slice identifier associated with the selected RAN slice prior to transmitting the data to the transmission point.
According to another aspect is a router for use in a radio access network (RAN) which includes a network interface for receiving and transmitting data, a processor, and a non-transient memory for storing instructions. When executed by the processor, the instructions cause the router to: transmit data traffic, over the network interface, to a transmission point associated with a selected RAN slice within the RAN, in response to receiving data traffic destined for a User Equipment (UE) over the network interface. In some examples, the instructions cause the router to select the RAN slice in accordance with one of an identifier associated with the core network; an identifier associated with a slice of the core network associated with the received data; and a service identifier associated with the received data. In some examples, the identifier associated with one of the core network and the slice of the core network is one of an address of a core network gateway function and a tunnel identifier. In some example embodiments, the instructions cause the router to select the transmission point in accordance with information about the location of the UE with respect to the network topology. In some examples, the instructions cause the router to select a transmission point uniquely associated with the UE; determine a set of constituent access points associated with the selected transmission point; and transmit the data to the transmission point by transmitting the data to the set of constituent access points. In some examples, the instructions cause the router to modify the received data prior to transmission to the transmission point to include a RAN slice identifier associated with the selected RAN slice.
FIG. 1 is a schematic diagram of an example communications system or network 100, in which examples described in the present disclosure may be implemented. The communications network 100 is controlled by one or more organizations and includes a physical core network 130 and a Radio Access Network (RAN) 125. In some examples, the core network 130 and RAN 125 are controlled by a common network operator, however in some examples the core network 130 and RAN 125 are controlled by different organizations. In some embodiments, multiple RANs 125, at least some of which are controlled by different network operators, may be connected to a core network 130 that is controlled by one or more of the network operators or by an independent organization. Core Network 130 is sliced, and shown having CN Slice 1 132, CN Slice 2 134, CN Slice 3 136 and CN Slice 4 138. It should also be understood, as will be discussed in more detail below, that a plurality of core networks can make use of the same RAN resources.
An interface between the core network 130 and RAN 125 is provided to allow traffic from CN 130 to be directed towards UEs 110 through access points (APs) 105, which may be base stations, such as an evolved Node B (eNB) in the Long-Term Evolution (LTE) standard, a 5G node, or any other suitable nodes or access points. APs 105, also referred to as Transmit/Receive Points (TRPs), may serve a plurality of mobile nodes, generally referred to as UEs no. As noted above, in the present description access point (AP) is used to denote the wireless edge node of the network. Thus, the APs 105 provide the radio edge of RAN 125, which may for example be a 5G wireless communication network. The UEs no may receive communications from, and transmit communications to, the AP's 105. Communications from the APs 105 to the UEs no may be referred to as downlink (DL) communications, and communications from the UEs no to the APs 105 may be referred to as uplink (UL) communications.
In the simplified example shown in FIG. 1, network entities within the RAN 125 may include a resource allocation manager 115, a scheduler 120, and a RAN slice manager iso, which may in some embodiments be under the control of the network operator who controls RAN 125. The resource allocation manager 115 may perform mobility-related operations. For example, the resource allocation manager 115 may monitor the mobility status of the UEs 110, may oversee handover of a UE 110 between or within networks, and may enforce UE roaming restrictions, among other functions. The resource allocation manager 115 may also include an air interface configuration function. The scheduler 120 may manage the use of network resources and/or may schedule the timing of network communications, among other functions. RAN slice manager 150 is configured for implementing RAN slicing, as described in greater detail below. It should be understood that in some embodiments, the scheduler 120 is a slice specific scheduler and is specific to the RAN slice, and not common to the RAN. Those skilled in the art will further appreciate that in some embodiments, some slices will have a slice specific scheduler, while other slices will make use of a common RAN scheduler. A common RAN scheduler may also be used to coordinate between slice specific schedulers so that the common RAN resources are properly scheduled.
In example embodiments, the core network 130 includes a core network slice manager 140 for implementing (and optionally managing) core network slicing. As shown in FIG. 1, Core Network 130 has four illustrates slices CN Slice 1 132, CN Slice 2 134, CN Slice 3 136 and CN Slice 4 138. These slices can, in some embodiments, appear to the RAN as distinct Core Networks. The UEs no may include any client devices, and may also be referred to as mobile stations, mobile terminals, user devices, client devices, subscriber devices, sensor devices, and machine type devices for example.
Next generation wireless networks (e.g. fifth generation, or so-called 5G networks) are likely to support a flexible air interface in RAN 125 that allows for the use of different waveforms, and different transmission parameters of each of the waveforms (e.g. different numerology for some of the supported waveforms), different frame structures, as well as different protocols. Similarly, to take advantage of a large number of APs 105, which may take the form of both macro and pico-cell sized transmission points operating in different frequency bands, it is possible that a 5G network will group a series of APs 105 to create a virtual transmission point (vTP). The coverage area of a vTP may be referred to by some as a hyper-cell. By coordinating the transmission of signals from the APs 105 in the virtual TP, the network 125 can improve capacity and coverage. Similarly, a grouping of APs 105 can be formed to create a virtual receive point (vRP) that allows for multipoint reception. By varying the APs 105 in the virtual groups, the network 100 can allow the virtual TP and RP associated with an UE 110 to move through the network.
From the perspective of a network operator, deploying network infrastructure can be very expensive. Maximizing the utilization of the deployed infrastructure, and the wireless resources, is of importance to allow network operators to recover their investments. The following disclosure provides systems and methods for enabling network slicing at the radio edge of RAN 125, and for facilitating routing of traffic between slices of the radio edge of RAN 125 and core network 130, which may also be sliced. In some examples, this can enable an end-to-end network slice, and allows network operators to then divide the network and provide service isolation in wireless connections within a single network infrastructure.
Referring to FIG. 2, in example embodiments the RAN slice manager 150 is configured to create and manage RAN slices 152. Each of the RAN slices 152 have a unique allocation of RAN resources. The RAN resources that are available for allocation can be categorized as: RAN access resources, which include

- the AP's 105 and UEs 110;
- radio resources, which include:
- wireless network frequency and time (f/t) resources 158, and
- spatial resources based on the geographic placement of APs 105 associated with the slice and based on the directionality of transmissions if advanced antenna technologies are applied; and
- radio air interface configurations 160 that specify how the radio resources and the access resources interface with each other.

The radio air interface configuration 160 can, for example, specify attributes in one or more of the following categories: the radio-access technology 162 to be used for the slice (e.g. LTE, 5G, WiFi, etc.); types of waveform 164 to be used (e.g. orthogonal frequency division multiple access (OFDMA), code division multiple access (CDMA), sparse code multiple access (SCMA) etc.); numerology parameters 166 for the specified waveforms (e.g. subcarrier spacing, transmission time interval length (TTI), cyclic prefix (CP) length, etc.); frame structures 165 (e.g. UL/DL partition configuration for TDD system), applicable multiple-input-multiple-output (MIMO) parameters 168; multiple access parameters 170 (e.g. grant/grant free scheduling); coding parameters 172 (e.g. type of error/redundancy coding scheme); and functionality parameters for APs and UEs (e.g. parameters governing AP handover, UE retransmission, UE state transition, etc.). It will be appreciated that not all embodiments may include the entire list of radio transmission functions describe above, and in some cases there may be overlap in some of the categories stated above—for example a specific waveform may be inherently defined by a specified RAT.
In example embodiments, the RAN slice manager 150 manages the allocation of RAN resources for the specific RAN slices 152 and communicates with resource allocation manager 115 and scheduler 120 to implement service specific RAN slices 152 and to receive information about RAN resource availability. In example embodiments, the RAN slice manager defines the RAN resources for RAN slices 152 based on slicing requirements received from the core network 130, and in particular the core network slice manager 140.
RAN slices are each instances that can be set up and maintained for varying durations, ranging from long term instances that may be set up and maintained indefinitely, to temporary RAN slice instances that may last only momentarily for a specified function.
In example embodiments, RAN slice manager 150 is configured to implement RAN slicing to affect one or more of the following functions: service isolation within a carrier, dynamic radio resource allocation taking slices into account, a mechanism for a radio access network abstraction, per-slice based cell association, a handover mechanism at the physical layer and a per-slice state machine. Those skilled in the art will appreciate that this list is neither exhaustive nor is it essential to have all the features to provide RAN slicing. RAN slicing in respect of these functions will now be described in greater detail.
In at least some examples, the RAN slices 152 are each associated with a specific service. In another embodiment, any or all of the RAN slices 152 can carry traffic associated with a set of services. Services which would require a RAN slice 152 with similar parameters and characteristics can be grouped together on a single slice to reduce the overhead of creating distinct slices. The traffic associated with the different services can be differentiated through the use of service identifiers, as will be well understood. As illustrated in FIG. 2, RAN slice 152 will be associated with a set of APs 105 nodes (AP set 154) and a set of receiving UEs 110 (UE set 156) communicating with each other using specified air interface configuration 160 and a set of radio frequency/time resources 158. The UEs no within UE set 156 are typically the UEs that are associated with services within the slice 152. By creating a slice, a set of resources is allocated, and the traffic in the slice is contained such that different services that use the RAN 125 can be isolated from each other. In this regard, in example embodiments, isolation means that communications that occur in respective contemporaneous RAN slices will not affect each other, and additional RAN slices can be added without impacting the communications occurring in existing RAN slices. As will be explained in greater detail below, in some example embodiments isolation can be achieved by configuring each RAN slice 152 to use a different air interface configuration 160 (including waveform numerology 166). By selecting an air interface configuration 160 based on the requirements of the slice, it may be possible to improve the performance of the slice, or to reduce the impact of the resource usage of the slice, this may be achieved through the use of waveforms that have better spectrum localization. For example, sub-band filtering/windowing can be applied at a receiver to reduce interference between adjacent sub-bands that apply different numerologies. As will be discussed further below, different RAN slices 152 can be associated with different sets of physical transmit and receive nodes.
Accordingly, those skilled in the art will appreciate that although slices can be differentiated by the allocated by radio time/frequency resources 158, they could also be differentiated by the assigned air interface configuration 160. For example, by allocating different code based resources 172, different slices can be maintained separately. In access technologies that make use of different layers, such as Sparse Code Multiple Access (SCMA), different layers can be associated with different slices. Slices may be separated from each other in a time domain, a frequency domain, a code domain, a power domain, or special domains (or any combination of the above).
In some embodiments, allocating a set of time/frequency resource pairings 158 to the slice allows the traffic intended for the slice to be transmitted over dedicated radio resources. In some embodiments, this could include the allocation of an entire frequency band at fixed time intervals to a slice, or it could include allocation of a dedicated subset of the available frequencies to the slice at all times. Both of these can provide service isolation, but they may be somewhat inefficient. Because such a scheduling of resources is typically predefined, there may be long periods of time between redefinition of the resources during which the allocated resources are not fully used. The redefinitions cannot be too frequent if there are devices that have long periods of being idle, or these devices would have to frequently re-connect to the network to obtain this information. Accordingly, in example embodiments, service isolation over a common carrier (for example within the same carrier frequency) allows independent co-existence of multiple services within the same carrier. Physical and other resources can be dedicated on slice by slice basis within a set of dedicated slice resources. As noted above, in 5G networks, it is anticipated that a number of different protocols and waveforms, some of which may have a number of different numerologies, can be supported.
In some examples, resource allocation manager 115 includes a slice-aware air interface configuration manager (SAAICM) 116 that controls AP 105s based on the air interface configuration assignments made to the RAN slices 152 by RAN slice manager 150, thus allowing a waveform and numerology to be dedicated to a slice 152. All nodes (AP's 105 or UEs no) transmitting data in the slice are then allocated transmission resources by network scheduler 120, based on the network f/t resource parameter set assigned by at least one of RAN slice manager 150, and the nodes transmitting within the allocated AP resources 154 and UE resources 156. This allows a network entity or entities such as the RAN slice manager 150 and resource allocation manager 115 to adjust the resource allocation dynamically, as discussed in greater detail below. The dynamic adjustment of resources allocations allows a slice 152 to be provided a minimum level of service guarantee without requiring that the resources used to provide this level of service are dedicated exclusively to the slice. This dynamic adjustment allows resources that would otherwise be unused to be allocated to other needs. Dynamic dedication of the physical resources may allow a network operator to increase the usage of the available nodes and wireless resources. A network entity or entities, such as the RAN slice manager 150 and resource allocation manager 115 can assign parameters to each slice based on the requirements of the service supported by that slice. In addition to the service isolation discussed above, the generation of a slice specific to a service (or a class of services) allows for the RAN resources to be tailored to the supported services in some embodiments. Different access protocols can be offered for each slice, allowing for example, different acknowledgement and re-transmission schemes to be employed in each slice. A different set of Forward Error Correcting (FEC) parameters can also be set for each slice. Some slices may support grant free transmissions, while others will rely on grant based uplink transmissions.
Accordingly, in some example embodiments the RAN slice manager 150 is configured to enable service isolation by differentiating the air interface configuration 160 for each service-centric RAN slice 152. In at least some examples, the differentiation amongst the attributes of different air interface configurations 160 assigned by the RAN slice manager 150 to different RAN slices 152 can provide service isolation even when the other RAN slice parameter sets (for example one or more of the AP set 154, UE set 156, and Network f/t set 158) are similar.
FIG. 3 illustrates an example of service isolation within a carrier. In particular, in the example of FIG. 3, three services S1, S2 and S3 are each assigned a respective RAN slice 152(S1), 152(2) and 152(S3) by RAN slice manager 150 for use in a common frequency range allocation (common carrier) in which the RAN slices have been assigned adjacent frequency sub-bands in RAN 125. In the example of FIG. 3, the RAN slices 152(S1), 152(S2) and 152(S3) assigned to the three services S1, S2 and S3, all include identical allocations in respect of the AP set 154 and UE set 156, and having similar network f/t resources 158 with adjacent sub-band allocations. However, the air interface configurations 160 allocated to the three services S1, S2 and S3 are differentiated in order to provide service isolation, even though the services are intended to operate using similar carrier frequency resources (namely, adjacent sub-bands as specified in network f/t resources 158). In the illustrated example the differentiation is provided in one or both of the waveform 164 and numerology parameter 166 assignments. The numerology parameters define parameters of the specified waveform. For example, in the case of an OFDMA waveform, the numerology parameters include the sub-carrier spacing, the length of a cyclic prefix, the length of an OFDM symbol, the duration of a scheduled transmission duration and the number of symbols contained in a scheduled transmission duration.
Specifically, in the example of FIG. 3, RAN slice 152(S1) and RAN slice 152(S2) have each been allocated the same waveform function (OFDMA), but have each been allocated different numerology parameters (Numerology A and Numerology B, respectively) to apply to the waveform function. For example, Numerology A and Numerology B may specify different TTI lengths and subcarrier spacing for the respective OFDMA waveforms. The third RAN slice 152(S3) has been allocated a different multiple access function 170 (for example SCMA), and a set of numerology parameters suitable for the waveform associated with the different multiple access function (Numerology C).
In some examples, the different transmission function 160 parameters allocated to the different RAN slices may sufficiently distinguish the different services such that the RAN slices can be implemented in overlapping frequencies in overlapping times. However, in some embodiments, time differentiation may also be required, which may for example be implemented by scheduler 120.
In some example embodiments, service isolation can also be implemented through differentiation in the access resources allocated to different RAN slices. For example, the AP set 154 assigned to different RAN slices 152 can be sufficiently different that geographic isolation occurs. Also, as noted above, different network frequency/time resources 158 can be used to isolate different RAN slices.
In example embodiments, the parameters set for RAN slice instances can be dynamically varied based on real-time network demands and available resources. In particular, in example embodiments, RAN slice manager 150 is configured to monitor the real-time demands and available resources across RAN 125 and the RAN slices 152 and based on the monitored information and the performance requirements defined for specific services (for example the performance requirements set out in an SLA), the RAN manager 150 can re-define the allocations it has made in respect of the slices.
FIG. 3 further illustrates the presence of AP2 105 in RAN 125. AP2 105 serves a different UE 110 than is shown served by AP 105, and supports services in Slice 1 152(S1) (which is one of the slices supported by AP 105), and Slice 4 152 (S4). The parameters of Slice 4 152 (S4) are not illustrated, but they should be understood to be different than those of Slice 1 152(S1). A UE 110 connecting to Slice 1 152(S1) can thus be served by either or both of AP 105 and AP2 105. It should also be understood that not all APs within a single RAN need to support the same set of slices.
FIG. 4 schematically illustrates a set of RAN resources associated with a common carrier (for example RAN 125), and, in particular, radio frequency/time (f/t) resources. In the example of FIG. 4, resource allocation manager 115 allocates f/t resources, in accordance with instructions received from RAN Slice Manager 150, to slices 152(S4), 152(S5), and 152(S6) that are each associated with a specific service S4, S5 and S6, respectively. A service S4 may be directed towards ultra-low-latency-reliable communications (ULLRC) devices is allocated resources associated with ULLRC slice 152(S4), a service S5 for mobile broadband (MBB) is allocated resources associated with MBB slice 152(S5) and a service S6 for massive Machine Type Communications (mMTC) is allocated resources associated with mMTC slice 152(S6). As represented in FIG. 4, the allocation can be dynamic as the assignment of relative frequency resources within the common carrier RAN resources 200 can change from time T1 to time T2. Additionally, between times T1 and T2 different resource allocations for each slice 152 can be made by setting different radio air interface configurations 160 for each slice, including one or more of numerology, waveforms and protocols. Other RAN slice resource parameters, including for example physical access resources (AP set 154 and UE set 156), can also be allocated differently to the different slices between times T1 and T2. Although the frequency resources are illustrated as being continuous in FIG. 4, the frequency sub-bands assigned to the respective slices need not be continuous and within each slice 152 the assigned frequency sub band resources may be non-continuous. Although one MBB slice 152(S5) is shown in FIG. 4, there may be multiple MBB slices, as well as additional non-MBB slices. As will be appreciated from the above description, by using different numerologies, different waveforms and different protocols for different slices 152(S4), 152(S5), and 152(S6), traffic from each slice 152(S4), 152(S5), and 152(S6) is effectively isolated. Functions and nodes within each slice (e.g. the devices (UEs 110) or entities (APs 105) that support the service associated with the slice) only know their own numerology, and this allows for isolation of their traffic. In example embodiments, in order reduce interference between the channel frequency resources assigned to different slices with different numerologies, sub-band filtering or windowing is applied at the receiving AP105 or UE 110 to further enhance localization of the waveforms with different numerologies. In example embodiments, in order to accommodate varying levels of functionality at AP's 105 and UEs 110, the RAN slice manager may allocate sets of alternative air interface configurations 160 to each RAN slice 152, with the resource allocation manager 115 or AP 105 selecting the appropriate transmission functions at the time of transmission.
Radio f/t resources can be viewed as two dimensions in a resource lattice. In FIG. 4, the differing physical sizes of the blocks represent relative use of the radio resources in RAN 125 by services S4, S5 and S6 as dictated by the slice allocations made by RAN slice manager 150 and implemented by Resource Allocation Manager 115 and Scheduler 120. By using a scheduling method that allows for variations in the lattice assignments and different waveforms to be transmitting in different resource blocks in the lattice, dynamic allocation of the resources can be performed. A flexible lattice combined with the ability to assign different transmission function resources such as different waveforms with different numerologies, provides an added dimension of control. Radio f/t resource assignment can be changed dynamically according to the change of the loading of different slices.
One skilled in the art will appreciate that resources can be allocated to slices 152 to account for the very different traffic profiles that different slices may have. For example, mobile broadband (MBB) connections are sporadic, but very high volume, while Machine Type Communications (MTC) devices typically generate traffic profiles that have a large number of devices communicating small amounts of data at fixed intervals, or in response to an event, and devices connecting to a URLLC service generate high volume traffic that may be quite consistent over the limited time period in which they are active, and may be resource intensive due to the need for both low latency and reliability. Instead of dedicating resources to either ULLRC deployments, or to massive MTC deployments, resulting in unused resources when they are not generating traffic, the resources allocated to other services, such as MBB, can be increased while the URLLC and mMTC services are not consuming their allocation of resources. An example of such a change in allocation is illustrated in FIG. 2 in which the portion of resources 200 allocated to MBB slice 152(S5) is increased at time T2 relative to time T1, whereas the portion of resources 200 allocated to ULLRC slice 152(S4) and mMTC slice 152(S6) is decreased at time T2 relative to time T1. Different waveforms can be selected for different types of connections, and different numerologies for a single waveform can be used to differentiate between two slices serving similar connection types (e.g. two MTC services could both use the same waveform but with different numerologies) to maintain both service isolation and efficient use of the spectrum resources.
In at least some examples, RAN slices can be used to decouple UEs no from a physical AP 105 and provide a layer of radio access network abstraction. For example, different RAN slices 152 can be assigned different AP sets 154, such that UE 110 can maintain a first session for a first service with a first AP 105 using a first RAN slice 152(S1), and also maintain a second session for a second service with a second AP 105 using a second RAN slices 152(S2). Such a configuration allows APs that that are most suitable for the specific services to be used. It should be understood that a set of APs can be grouped together to form a virtual access point. The service area of the virtual access point can be represented as the union of the service areas of the constituent APs. The vAP can be assigned an AP identifier. The vAP can be specialized so that it is either a transmit or receive point (vTP, vRP). A plurality of different vAPs can have overlapping memberships so that each vAP is composed of a plurality of different physical APs, with some of the physical APs being part of different vAPs. Some vAPs may have identical memberships to other vAPs.
In some embodiments, the RAN slice manager 150 may be configured to allocate both logical access resources and physical access resources to a RAN slice 152. For example, with reference to FIG. 5, there are a number of APs 105. Instead of each AP 105 operating independently, they can be used to create a virtual AP as discussed above. A virtual TP 176 and a virtual RP 178 can be created with differing, but overlapping sets of APs. Different vTPs and vRPs can be created for each slice. In addition to allocating different physical resources to a slice, the RAN slice manager 150 can allocate logical resources such as vTP 176 and vRP 178 to each slice. United States Patent Publication No. US2015/0141002 A1 entitled “System and Method for Non-Cellular Wireless Access”; United States Patent Publication No. US2014/0113643 A1 entitled “System and Method for Radio Access Virtualization” and United States Patent Publication No. US2014/0073287 A1 entitled “System And Method For User Equipment Centric Unified System Access In Virtual Radio Access Network”, which are incorporated herein by reference, describe wireless networks in which UEs are associated with virtual TPs and RPs. In example embodiments, aspects of the virtualization and abstraction methodologies disclosed in these patent publications can be performed in respect of RAN slices to implement the slice specific virtualization and abstraction as described below.
In some embodiments, various devices (UEs no) connecting to wireless network (RAN 125) will each participate in one or more different services (e.g. ULLRC service S4, MBB service S5, mMTC service S6), and each service can be assigned a different RAN slice 152. Resource allocation manager 115 can assign different slices to each virtual TP 176 or RP 178 to be adjusted along with demand. For example, a UE 110 that supports multiple services, such as both an MBB service, and an ULLRC service used to relay information such as that generated by a heart rate monitoring service, could transmit data associated with each of these services on different slices. Each slice could be assigned different encoding formats, and may be transmitted to the respective slices using different virtual RPs 178. The UE 110 could provide an indication of the slice 152 that is being used to the RAN slice 125 when there was data to transmit.
As a UE 110 moves, it may remain connected to the same virtual transmit point/receive point TP/RP 176,178, but the physical access points (APs 105) in the virtual access point TP/R176,178 will change. Furthermore, as a UE 110 moves a greater distance, it may be possible that the physical AP or radio t/f resources initially used are no longer available to the RAN 125. This can happen when the UE 110 travels sufficiently far that the spectrum allocated to the slice by the carrier is no longer available, or it could happen if the network operator makes use of infrastructure owned by another entity in one area, and cannot access the same resources in another. In the latter case, it may also be that the particular waveform assigned to the slice 152 for the UE 110 to use while transmitting over the RAN 125 is no longer available. In such a case, resource allocation manager 115 can notify the UE 110 that the transmission parameters will change at a certain geographic point. This may, in some embodiments, be performed as part of a handover procedure. It should also be understood that when a virtual TP/RP 176,178, or other vAP, is associated with a UE 110 on a per-slice basis, there may be occasions in which a handover occurs for one slice, but not another. This may occur in a number of different scenarios, including ones in which a UE 110 connects to a first service provider for a first service in a defined slice, and connects to a second service provider for a second service in another defined slice. In such a scenario, it is likely that the boundaries between APs or vAPs will vary between the service providers. In a scenario in which both services are provided through the same provider (or at least access services are provided by the same provider), boundaries between APs that are slice specific may not align, which will result in a per-slice handover.
In some examples, waveform parameters 164 could be changed when a UE 110 is handed over to (or otherwise served by) a different TP 170 operating in different frequency bands. A RAN slice 152 may have two alternative TPs 176 assigned to it for serving a UE no, with one TPs 176 operating in a high frequency band, such as the mm band, and the other TP 176 operating in a lower frequency. The switch between different frequency bands, and corresponding switch between the APs used to serve the UE 110 for the slice 152, can be dynamic depending on a scheduling decision made at scheduler 120 and implemented by resource allocation manager 115.
By having the UE 110 connect to virtual access points TP/RP 176,178, the UE no can be logically decoupled from the actual physical infrastructure. This can mitigate problems associated with cellular handover, and cell edge interference. Different sets of physical APs 105 can be allocated to the virtual TPs 176 and virtual RPs 178, so that different slices can be served by different sets of hardware resources. This could allow a network operator to dedicate expensive and high capacity access points to services such as MBB, and lower cost APs 105 to services such as MTC services. Additionally, allocating TPs 176 and RPs 178 as separate logical entities can be used to decouple the Uplink and Downlink data paths, which may, in some circumstances, allow for better usage of the network infrastructure. If a given RAN slice 152 is dedicated to MTC devices that generate uplink traffic at fixed intervals, but are rarely sent any downlink traffic, the slice can be served by a set of virtual RPs 178 that is designed to be more robust than virtual TPs 176. This allows for resource allocation to serve the needs of service assigned to the RAN slice 152, to a finer grained level than would be possible if APs are assigned in their entirety (as would be required in a conventional LTE network where an eNodeB would be allocated and would provide bi-directional service).
The creation of virtual TPs 176 and RPs 178 may also be referred to as the generation of a hypercell. A hypercell allows for multiple physical APs 105 to work together to serve a UE no. The hypercell can be associated with both a UE 110 and a RAN slice 152. This allows for a UE 110 to communicate with different hypercells in each slice. Each hypercell can then be configured for the specific needs of the slice that it is associated with. For example a UE no may communicate with a first hypercell (TRP) in respect of one first service-centric RAN slice 152(S4), and with a second hypercell for traffic associated with a second service-centric RAN slice 152(S5). The slices that carry traffic associated with an MTC service may be directed to serving stationary MTC devices (in the case where UE 110 is an MTC device). A slice dedicated to stationary MTC devices can be designed to be stable and relatively unchanging in their membership. Other slices, such as those dedicated to mobile MTC devices, such as intelligent traffic systems devices, and other such mobile services, can be configured to accommodate greater mobility. The slice that supports stationary MTC devices may also be designed to have limited function in the mobility management function (e.g. a Mobility Management Entity), due to the limited mobility of the supported devices. It should be understood that although the use of hypercells allows for a reduction in the number of handovers, handovers may not be completely eliminated. Handovers may happen when the waveform and numerology assigned to a slice in the hypercell are not available or supported at all points along the path of a mobile UE. By requiring a handover to a new hypercell, the network may be able to ensure that the new slice specific information is transmitted to the UE 110.
As noted above, when different hypercells are used to serve different slices, a UE no may undergo a handover in a first RAN slice 152, without necessarily having to undergo a handover in another RAN slice 152. In some examples, RAN 125 may encompass network resources that are allocated among multiple network operators, with the different network operators each supporting different hypercells. Because they are served by different hypercells, different network operators can provide service support to the same UEs no for different service-based RAN slices 152. This allows network operators to provide different services, and for customers (either users or service operators) to select different network operators for different RAN slices 152 based on cost, coverage, service quality and other factors. Accordingly, in some examples, a UE 110 accesses a first service using a first RAN slice 152 that supported by a first network operator, and the same UE 110 can then access a second service using a second RAN slice 152 that supported by a second network operator.
Another example of the assignment of different access resources to different slices 152 will now be described with reference to FIG. 6. As discussed above, and as shown in FIG. 6, a single UE, such as UE 110 can connect to different access points (both physical and virtual) for different services. Although APs 602, 604 and 606 are illustrated as physical APs, it should be understood that they can also represent a virtual AP with several constituent APs. In some examples, RAN 125 is a heterogeneous network with different types of APs, and possibly supporting different RATs. AP 602 is an access point, also referred to as a macrocell, that can provide a wide coverage area, and typically provides access services in lower frequency bands. AP 602 would typically connect directly to the core network 130 and support a set of RATs (for example HSPA, LTE, 5G). Access points 604 and 606 can be APs directed to providing a smaller coverage area, and often referred to as small cells, picocells, and/or femtocells. APs 604 and 606 may connect to the core network 130 indirectly (for example through the Internet, through UE's that serve as relay devices, or through a fixed wireless connection to AP 602). In some implementations, AP 604 and 606 may connect directly to the core network. APs 604 and 606 may provide service in higher frequency band, such as mmWave, and/or they may support a different set of RATs (for example WiFi or access technologies dedicated to higher frequency APs). As shown in FIG. 6, where a heterogeneous network is available, different access technologies, or different waveforms, can be used, in conjunction with different access points, for access to different slices. The UE no, when in the service range of AP 604, may rely upon AP 604 to an MBB slice 152(S1). This may provide the UE 110 with higher speed or lower cost connectivity, and it may remove a high bandwidth connection from a larger AP such as AP 602. UE 110 may also connect to an IoT service for an MTC function. MTC connections may be served by an IoT slice 152(S2) that is accessed through AP 602 (which provide macrocell coverage). Macrocell coverage is often more ubiquitous, and can better support a larger number of devices at a given time than smaller APs such as AP 604. This increased coverage and ability to support a larger number of devices may come at the expense of lower data rates in comparison to smaller access points 604. As MTC devices often require low bandwidth connections, a large number of them may be serviced in IoT service slice 152(S2) through a connection to AP 602. UE 110 may also participate in a service that requires a URLLC connection, which is supported by URLLC service slice 152(S4). Downlink traffic in the URLLC slice 152(S4) may be transmitted in a high-frequency band by AP 606 which acts as a TP. However, to ensure that uplink traffic is reliably delivered, and is not subjected to handover between a large number of APs with smaller coverage areas, the uplink traffic in this slice can be directed to AP 602. It should be understood, that each AP may be represented by a virtual representation within each slice, so that uplink traffic in slice 152(S4) and uplink traffic in slice 152(S2) are sent to different logical vRPs, each of which are representations of the same physical AP. In 3G/4G networks, a UE 110 is typically connected to one RAN access point at a time, and all services are routed over the same connection. By supporting simultaneous connections to different access points (both real and virtual), different slices can be isolated across the common access medium. It will be understood by those skilled in the art that different waveforms can be used by the different slices (e.g. one slice may use an Orthogonal Frequency Division Multiple Access (OFDMA) waveform, while a second slice uses another waveform, such as a Sparse Code Multiple Access (SCMA) waveform), or both slices could use the same type of waveform with different numerologies (e.g. both could use OFDMA, but with different spectrum masks, different resource block sizes etc.). It will also be understood that the TTIs for each slice can be different, but in some embodiments will be multiples of a base TTI value.
In example embodiments, RAN slice manager 150 will allocate one AP set (or TP/RP sets) and a corresponding RAT or set of RATs to a first RAN slice 152, and different AP set (or TP/RP sets) and corresponding RAT or set of RATs to a second RAN slice. In some examples, overlapping sets of physical or virtual access points may be allocated to each RAN slice, but with different use priorities. For example MBB service slice 152(S1) will be allocated access points 604 as its primary RAN access with macro access points 602 as a backup; conversely IoT service slice 152(S2) will be allocated only macro access points 602 for its RAN access.
As described above, in at least some examples, each RAN slice 152 will effectively operate as a distinct virtual network, indistinguishable from a physical network to most network nodes. In some embodiment, each RAN slice 152 can provide network resources tailored to the needs of the service that operates within it. This may include the provision of both data and control planes in the network 100. Each slice may be provisioned with a number of network functions that may operate as state machines. A scheduler may be represented as a state machine within a slice to provide scheduling in grant-based and grant-free transmission environments. In a slice, it may be determined that grant-based transmissions will be used for transmission (e.g. a slice that supports MBB), while another slice may allow for grant free transmission (e.g. slices that support MTC or Internet of Things (IoT) devices). It is also possible for a slice to accommodate both grant free (or contention based) and scheduled uplink transmissions. In some implementations, the differing demands on the schedulers may result in the demands on a scheduler being very sufficiently different between slices that it may be advantageous for each slice to have its own scheduling function (or set of functions). This could be provided by a single scheduler that is represented within each slice as a logical scheduling state machine. Those skilled in the art will appreciate that the access parameters, the waveform, numerology and other slice specific parameters can be managed by the different state machines in either of the UE and network entities associated with the slice. Thus, a UE that is connecting to multiple slices may serve as a platform for multiple state machines.
A UE 110 that connects to different slices may support a different set of state machines for each slice that it connects to. These state machines will preferably run simultaneously, and there may be an arbitrator to ensure that contention for access to physical resources in the UE is handled. The different state machines within a UE may result in a UE that performs both grant free and scheduling based transmissions. There may also be, within a UE, a function that serves to coordinate the operation of the plurality of state machines.
Examples of state machine enabled UEs no and supporting networks are described in United States Patent Publication No. US2015/0195788 A1 entitled “System and Method For Always On Connections in Wireless Communications System”, United States Patent Publication No. US 2016/0227481A1 entitled “Apparatus And Method For A Wireless Device To Receive Data In An Eco State”, and U.S. patent application Ser. No. 15/165,985, entitled “System And Method Of UE-Centric Radio Access Procedure” all of which are incorporated herein by reference. In example embodiments, the state machine related functionality described in the above documents are implemented at the UE 110 and the network on a slice by slice basis rather than on a device level basis. By way of example, in one embodiment RAN 125 and UE 110 are configured to support different operating states for UE 110 in respect of each RAN slice 152(S1) and 152(S2), with each operating state supporting different UE functionality. In particular, in one example the UE 110 is configured to implement a state machine that can transition between two different states in respect of each RAN slice 152(S1) and 152(S2), namely a first “Active” state and a second, energy economizing, “ECO” state. In example embodiments, a reduced set of radio access functionality is supported in the ECO state compared to the Active state. At least some degree of connectivity to RAN 125 is supported in both states, such that UE 104 maintains an always-on connection to the RAN 125 in respect of both RAN slice 152(S1) and second RAN slice 152(S2). In some embodiments, the UE 110 is configured to receive both grant-free and grant based transmissions in the “Active” state, but only “grant-free” transmissions in the “ECO” state, and the UE 110 uplinks status information more frequently and on a different channel in the Active state relative to the ECO state.
Accordingly, a UE 110 that supports a per slice state machine can simultaneously operate in the same state for both RAN slices 152(S1) and 152 (S2) (for example Active state for both slices or ECO state for both slices) or in different states (for example Active state for one slice and ECO state for the other slice). In example embodiments, multiple states or different numbers of states may be supported for different RAN slices 152. In example embodiments, information defining if and what states are supported in a slice are specified in the AP/UE functionality parameter set 174 (see FIG. 2).
In another embodiment, a UE is connected to different RAN slices. The first slice can support a service such as eMBB, while the second supports a service that does not necessarily require the same level of connection reliability, such as an MTC service. While within the first slice, the UE may be in one of an Active or Idle state, within the MTC slice, the UE may be in any of an Active, Idle or ECO state. Normally, an MTC device may perform some grant-free or contention-based transmissions from an ECO state, and only enter the active state when there is a scheduled transmission window, or a pre-scheduled downlink transmission. The physical UE may allow for the MTC slice to perform transmissions without requiring transition out of an IDLE state, if it is in the active state within the eMBB slice. This can allow the MTC slice or process within the UE to take advantage of the active state of another portion of the UE.
It should be understood that although the above discussion has made reference to having a slice for each service, it may be more practical for the network to provide a limited number of slices, with each slice serving a number of different services that have sufficiently similar properties. In one example, a variety of different content delivery networks could coexist in a single RAN slice.
In the core network, it may be possible to provide each of the network supported services with their own slice, and have this slice associated with a corresponding RAN slice such that end-to end slice management can be carried out under the control of slice manager 130. In this regard, FIG. 7 schematically illustrates a Service Customized Virtual Network (SCVN) implementation in which Slices 1-Slice 5 are each implemented as a virtual network that extends through core network 130 and RAN 125. In an example embodiment, slice manager 130 exchanges information with each of core slice manager 140 and RAN slice manager 150 to create end-to-end service-centric Slices 1-Slices-5. Each of Slices 1 to Slices-5 includes a resource set for the core network that defines an associated core network slice and a resource set for RAN 125 that devices an associated RAN slice 152.
In embodiments in which both core and RAN slicing occur, resource allocation manager 115 (under instructions from Slice Manager 130) can ensure that traffic received in a slice from RAN 125 is provided to a virtualized decoder that is connected to the corresponding slice in the Core network 130. This ensures that as data is received from a UE 110 device, isolation is maintained as the decoding can take place within the appropriate network slice instead of at the common radio access point.
FIG. 8 is a schematic diagram of an example simplified processing system 400, which may be used to implement the methods and systems disclosed herein, and the example methods described below. The UE 110, AP 105, Resource Allocation Manager, Scheduler 120, slice manager 130, core network slice manager 140 and/or RAN slice manager may be implemented using the example processing system 400, or variations of the processing system 400. The processing system 400 may be a server or a mobile device, for example, or any suitable processing system. Other processing systems suitable for implementing examples described in the present disclosure may be used, which may include components different from those discussed below. Although FIG. 8 shows a single instance of each component, there may be multiple instances of each component in the processing system 400.
The processing system 400 may include one or more processing devices 405, such as a processor, a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a dedicated logic circuitry, or combinations thereof. The processing system 400 may also include one or more optional input/output (I/O) interfaces 410, which may enable interfacing with one or more appropriate input devices 435 and/or output devices 440. The processing system 400 may include one or more network interfaces 415 for wired or wireless communication with a network (e.g., an intranet, the Internet, a P2P network, a WAN and/or a LAN) or other node. The network interfaces 415 may include one or more interfaces to wired networks and wireless networks. Wired networks may use of wired links (e.g., Ethernet cable), while wireless networks, where they are used, may make use of wireless connections transmitted over an antenna such as antenna 445. The network interfaces 415 may provide wireless communication via one or more transmitters or transmit antennas and one or more receivers or receive antennas, for example. In this example, a single antenna 445 is shown, which may serve as both transmitter and receiver. However, in other examples there may be separate antennas for transmitting and receiving. In embodiments in which processing system is a network controller, such as an SDN Controller, there may be no wireless interface, and antenna 445 may not be present in all embodiments. The processing system 400 may also include one or more storage units 420, which may include a mass storage unit such as a solid state drive, a hard disk drive, a magnetic disk drive and/or an optical disk drive.
The processing system 400 may include one or more memories 425, which may include a volatile or non-volatile memory (e.g., a flash memory, a random access memory (RAM), and/or a read-only memory (ROM)). The non-transitory memories 425 (as well as storage 420) may store instructions for execution by the processing devices 405, such as to carry out methods such as those described in the present disclosure. The memories 425 may include other software instructions, such as for implementing an operating system and other applications/functions. In some examples, one or more data sets and/or modules may be provided by an external memory (e.g., an external drive in wired or wireless communication with the processing system 400) or may be provided by a transitory or non-transitory computer-readable medium. Examples of non-transitory computer readable media include a RAM, a ROM, an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a CD-ROM, or other portable memory storage.
There may be a bus 430 providing communication among components of the processing system 400. The bus 430 may be any suitable bus architecture including, for example, a memory bus, a peripheral bus or a video bus. Optionally input devices 435 (e.g., a keyboard, a mouse, a microphone, a touchscreen, and/or a keypad) and output devices 440 (e.g., a display, a speaker and/or a printer) are shown as external to the processing system 400, and connected to optional I/O interface 410. In other examples, one or more of the input devices 435 and/or the output devices 440 may be included as a component of the processing system 400. Embodiments in which processing system 400 is a network controller may lack a physical I/O interface 410, and instead may be a so-called headless server for which all interactions are carried out through a connection to network interface 415.
In example embodiments, a processing system 400 configured to implement RAN slice manager 150 may be configured to maintain information that specifies the resource allocations for each of RAN slices 152 in memory 425 or storage 420 or a combination thereof.
FIG. 9 illustrates an architecture 900 in which a sliced RAN interacts with a plurality of Core Network Slices. A RAN slicing manager 902 establishes traffic routes, and may be used to direct traffic from a CN slice to the appropriate TPs based on at least an identification of the CN slice, and in some cases in accordance with a service ID associated with a service carried by the slice. CM 904 has been sliced to create 4 slices, slice 1-1 906, slice 1-2 908, slice 1-3 910 and slice 1-4 912. Each of the slices of CM 904 carry traffic, and slice 1-1 906 is illustrated as carrying traffic associated with service 1 914, and service 2 916. CN2 918 has 3 slices, CN2-1 920, CN 2-2 922, and CN 2-3 924. Each slices carried traffic, and slice 2-2 922 is illustrated as carrying traffic for service 1 926 and slice 2 928. It should be understood that service 1 914 and service 1 926 are not necessarily the same service. If they each carry the same service ID, they may be differentiated based on the slice or even the CN from which they arrive. RSM 902 is illustrated as a discrete element for the purposes of ease of illustration in the figure. As will be apparent to those skilled in the art, the functions described can be incorporated into other elements, such as a set of routers that have been given routing instructions by an SDN controller.
Radio Access Nodes, such as base stations etc., have typically not performed slicing of the Radio interface. At best, static partitioning of time or frequency based resources has been employed to create virtual channels. As indicated above, slicing of the RAN can also be accomplished through the use of different waveforms, numerologies and transmission parameters. In a RAN, a plurality of APs may provide overlapping coverage areas. Some APs may be associated with all slices, other APs may be associated with a single slice, and still other APs may be associated with a subset of the slices. FIG. 9 illustrates 3 APs within the RAN, AP1 930, AP2 932 and AP3 934. As will be appreciated different types of AP can be used for different purposes. AP1 930 supports 4 different RAN slices, RAN slice 1 936, RAN slice 2 938, RAN slice 3 940 and RAN slice 4 942. AP2 932 supports two of the four RAN slices, RAN slice 1 936 and RAN slice 4 942. AP 3 934 supports RAN slice1 936 and RAN slice 3 940.
As traffic from the two CNs, is received within the RAN, RAN slicing manager 902 directs traffic on the basis of the CN, CN slice and service, to the respective RAN slice. As illustrated, service 1 914 within slice 1-1 906 is directed to RAN slice 1 936. Thus traffic from this service can be sent to all three of AP1 930 AP2 932 and AP3 934. Traffic from service 2 916, which is also traffic from slice 1-1 906, is transmitted over RAN slice 3 940, so RAN slice Manager 902 directs this traffic to AP1 930 and AP 3 934. Those skilled in the art will appreciate that as discussed earlier different services may carry the same service ID if they are within different CN slices. This may be a result of different service providers not knowing the service ID values used in other slices. Because the slice ID and even in some cases a core Network ID can be associated with traffic, the RAN slicing Manager can ensure that service 1 926 carried within slice 2-2 922 can be routed to RAN slice 3 940. As a manner of aiding in visual distinction, traffic from CN 1 904 is shown traversing a path indicated by a solid line, while traffic from CN 2 918 is shown traversing a path indicated by a dashed line.
Traffic from slice 1-2 908 is carried by RAN slice 2 938; traffic from slice 1-3 910 is carried by RAN slice 2 938; traffic from slice 1-4 912 is carried by RABN slice 4 194. Traffic from slice 2-1 920 is carried by RAN slice 2 938; traffic from both services 926 and 928 within slices 2-2 922 is carried by RAN slice 3 940, and traffic from slice 2-3 924 is carried in RAN slice 2 938.
FIG. 10 is a flow chart illustrating a method 1000 of routing downlink traffic at an RSM. Those skilled in the art will appreciate that this functionality may be carried out by routers with a RAN under the instruction of a controller, such as a Software Defined Networking Controller. As illustrated, traffic is received for transmission to a UE in step 1002. This traffic is received from a core network, and may be associated with one or both of a CN slice and a service. Any of the CN and optionally CN slice associated with the received traffic is identified in step 1004. In step 1006 a service ID associated with the traffic can optionally be identified. As will be understood, in the network of FIG. 9, the service ID for traffic from slice 1-1 906 has to be identified so that it can be differentially routed, while the service ID for traffic from slice 2-2 922 is not necessarily required because traffic from both slices is routed to the same RAN slice. In step 1008, a RAN slice associated with the identified CN, CN slice, and service ID (as appropriate) is selected. Data for transmission to a UE is then routed to the appropriate TP (which may be an AP) in accordance with the identified RAN slice in step 1010. A RAN slice ID may be associated with the traffic so as to aid the TP with selection of the transmission parameters. In other embodiments, the TP can be left to determine which of the RAN slices it supports the traffic should be transmitted over. As will be well understood by those skilled in the art, mobile networks are typically designed to allow for mobility of the connected UE. Thus, routing data to the appropriate TP after selecting the RAN slice may include selecting a TP based on information provided by a mobility management function that tracks the location of the UE with respect to the topology of the network. In another embodiment, the TP may be a logical entity composed of a changing set of physical APs that are selected to track the location of the UE. In such an embodiment, the TP may be uniquely associated with a UE, and forwarding the data to a TP may be a function of selecting a TP associated with the UE and determining the set of APs currently associated with the TP. Data can then be transmitted (using any number of techniques including a multicast transmission) to the constituent APs within the selected TP.
FIG. 11 is a flow chart illustrating a method 1100 for handling downlink traffic at an AP (optionally a TP). Traffic for transmission to a UE is received at an AP in 1102. Optionally, the received traffic is associated with a RAN slice that is supported by the AP in 1104. This may have been previously performed in the RAN, in which case is does not need to be redone. The association with a RAN slice can be carried out in accordance with any number of different identifiers, including a core network ID, a core network slice ID, a service ID, or as will be discussed in FIG. 12 a tunnel ID or gateway address. In step 1106, the AP can select RAN transmission parameters in accordance with the RAN slice. If an AP only supports a single slice this step does not need to be performed, nor would it need to be performed if the parameters are otherwise provided to the AP. In step 1108, the data is transmitted to the UE using the parameters associated with the RAN slice that the data is associated with. As will be understood with reference to the above discussion, these parameters can include a specification of f/t resources, a waveform selection, numerology parameters and other such transmission characteristics.
FIG. 12, illustrates an architecture 1200 associated with the network illustrated in FIG. 9. For ease of explanation, only a single CN is illustrated, and only a single AP is illustrated. CM 904 is shown connecting to AP1 930. The RAN is sliced to provide RAN slices 1-4 as previously discussed in FIG. 9. It should be understood that within CN Slice 1-1 906 there is a gateway function 1202. This gateway 1202 is the connection points between slice 1-1 906 and the RAN. This means that all traffic from slice 1-1 906, including traffic associated with both service 1 914 and service 2 916, will be sent to the RAN through GW 1202. Similarly, traffic from slice 1-2 908 will be sent through GW 1204, traffic from slice 1-3 910 will be sent through GW 1206 and traffic from slice 1-4 912 will be sent through GW 1208. In the terminology associated with current LTE networks, the traffic from a gateway is sent to AP1 930 using a GPRS Tunneling Protocol (GTP) tunnel; in this case because it is user plane traffic a GTP-U tunnel. This GTP-U tunnel has an identifier associated with it. The GTP-U tunnels, or their analog in future generations of networks, can be designed to route traffic to the APs that support the RAN slice that the CN slice and services are directed to. This setting up of the tunnels can be performed by a controller, such as SDN Controller 1210, and put into effect by transmitting instructions to routing functions within the RAN. Similarly, SDN controller 1210 can provide instructions to AP1 930 to allow it to select the appropriate RAN slice for received traffic in accordance with at least of a tunnel ID associated with the tunnel that the traffic is received over, and an address of the gateway that the traffic is received from. Where a GW or a tunnel is associated with a CN slice that supports services that are routed to different slices, the AP can be instructed to associate traffic based on the CN slice and the service ID (as indicated in FIG. 11 at step 1104).
In the uplink, it will be understood that a UE, such as UE 110 can have a plurality of different virtual machines, each of which is used for the services associated with a different RAN slice. This allows the UE to be associated with different vAPs for each slice, and further allows handovers to happen on a per slice basis. An AP, such as AP 1 930 will receive traffic associated with a RAN slice. This traffic will also carry an indication of the CN or CN slice with which it is associated, and may also include an indication of the CN service it is associated with. This information can be used by the AP to select any of the tunnels that the traffic is transmitted to, the GW to which the traffic is transmitted, and the CN or CN slice that the traffic is to be transmitted to. In accordance with this destination information, the AP can transmit the received data to the associated CN slice. It should be understood that in situations in which there is a one to one mapping between the RAN slice and a CN slice, the AP can direct traffic to a CN slice on the basis of the RAN slice over which it is received. Where a RAN slice supports traffic from a plurality of different CN slices, further information, such as a CN slice ID, or a unique service ID, can be used to make the determination.
Those of skill in the art will appreciate that in an embodiment of the present invention, there is a method 1300 as illustrated in FIG. 13. The method is directed to the creation of a plurality of RAN slices that can be applied to radio communications in the RAN. Each of the RAN slices can be assigned a unique allocation of RAN resources. The unique allocation provides isolation from transmission in other RAN slices. This allocation of resources can include a unique set of transmission parameters. The method can be carried out at a controller, such as SDN controller 1202. In step 1302, instructions are transmitted to an AP to create a plurality of slices in the radio edge of the RAN. Information about core networks and possibly core network slices that will be served by the RAN slices is received in 1304. This information may include identification of the gateways from which traffic is to be received, and may also include identification of the services carried in the core network(s). This information may also include information about the nature of the traffic in the core network. Optionally, this information is used to determine transmission requirements (e.g. radio edge transmission requirements) in step 1306. In 1308, each of the core networks, or the core network slices, is associated with at least one slice of the radio edge of the RAN. It should be understood that if there are a plurality of different services carried within a core network, or core network slice, there may be more than one slice of the RAN radio edge associated with the core network or core network slice. In 1310, routing instructions based on the association of core networks or core network slices to the RAN slices is transmitted to nodes within the radio access network. This information may be transmitted to APs which are the interface between the radio edge slice and an unsliced portion of the RAN. The routing information may also be transmitted to routing functions within the RAN. These instructions may also be sent to gateway functions at the edge of the core network (or core network slice) and the RAN. The routing instructions may contain information that can be used to establish logical tunnels between the gateways and APs. This can enable a network to operation so that traffic from a core network or core network slice is directed to the APs associated with the radio edge slice assigned to the core network traffic.
In an optional embodiment, information associated with changing traffic demands or requirements for either a core network (or slice) or a radio edge slice is received. This information, received in optional step 1312, may indicate that there is excess capacity, or surplus demand for capacity in the radio edge slices. This information can be used to determine a new resource allocation for the radio edge slices, which can be transmitted to the respective nodes. In some embodiments this instruction may only be transmitted to the APs, or to a subset of APs. In other embodiments, the modification may create new radio edge slices, or remove existing radio edge slices, in which case a modification message (possibly not the same modification message sent to the AP) may be sent to other nodes in the RAN so that logical connections can be created or removed.
In some of the embodiments of the above described method, the RAN resources can include any or all of: network access resources that connect the RAN to a physical core network; radio frequency and time resources of the RAN; and an air interface configuration specifying how the network access resources interface with the radio frequency resources of the RAN. Optionally, at least some of the RAN slices can have common allocations of network access resources and adjacent radio frequency resources, with differentiating air interface configurations being allocated to each of the at least some of the RAN slices to isolate the radio communications of the at least some of the RAN slices from each other. The air interface configurations may specify waveforms for the RAN slices and numerology to apply to the waveforms. The plurality of RAN slices can comprises first and second RAN slices for which the air interface configurations specify the same waveform but different numerologies. In this manner, a numerology can allow a degree of isolation between the slices, as a receiver associated with the first slice would not be able to properly decode data transmitted in the second slice due to the differing transmission numerology. In one such example, the common waveform can be an OFDMA waveform, and the numerologies associated with each slice can have a different combination of one or more of: sub-carrier spacing, cyclic prefix length, symbol length, a duration of a scheduled transmission duration and a number of symbols contained in a scheduled transmission duration.
In another embodiment, different network access resources and different combinations of time and radio frequency resources can be allocated to RAN slices to provide isolation.
Those skilled in the art will appreciate that this method allows for the association of RAN slices with respective core network slices (or services within the core network slices) to enable communications associated with service to use a RAN slice and its associated core slice.
In other embodiments, for at least one of the RAN slices, the network access resources comprise at least one logical transmit point for downlink communications and at least one logical receive point for uplink communications. The TP and RP can be based on different sets of physical access points. In some embodiments, there may be overlap between the membership of physical access points within the logical TP and RP. In other embodiments there may be no overlap. Even if the membership of the physical APs is identical, the assignment of different logical identifiers to a TP and RP associated with a slice create a logical distinction for a UE. It is also possible that a set of physical APs assigned to a TP or RP in one slice may differ from the set of physical APs assigned to a TP or RP in another slice. The membership of the TP or RP in any slice can be changed without informing the UE, so long as the logical TP or RP identifiers are maintained. A UE may be communicating with the same set of physical APs in two different slices without being aware of this overlap.
After the establishment of the slices, and the definition of logical TPs and RPs within each slice, traffic destined for a UE attached to more than one slice can be received and routed to the APs associated with the CN, CN slice, or service, that the traffic is associated with. The traffic can then be transmitted to the UE using the transmission parameters associated with the RAN slice. Traffic associated with a different slice may be transmitted to the UE by a different logical TP, which may or may not have the same physical APs.
When the UE has traffic to transmit, it can transmit the traffic to the RP associated with the slice associated with the respective service. Based on any or all of an identification of the UE, the RP that traffic is received over, a service identifier associated with the transmission, and a destination address, the received traffic can be routed to the appropriate core network or core network slice.
Systems and methods are provided for configuring and using hyper cells. The hyper cell provides a wireless access for a coverage area with non-cellular grid among the APs; the coverage area serves a user equipment (UE) moving freely in the coverage area. Access points are organized into hyper cells, with different sets of hyper cells providing different services. The same access point can be included in multiple hyper cells.
Communications to and/or from the access points of a given hyper cell are randomized with a hyper cell specific randomization sequence. Mechanisms for configuring the air interface of hyper cells on a per service basis are provided. A broad aspect of the invention provides a method in an access network having a plurality of access points. For each of a plurality of services at least one respective cell is used to transmit and/or receive signals in respect of the service, each cell comprising at least one access point of said plurality of access points. Optionally, each cell has a respective randomization sequence or scheme, the method further involves in the at least one access point of each cell, using the respective randomization sequence or scheme of the cell when transmitting and/or receiving signals in respect of the service. Optionally, the method further involves for transmissions to or from a UE by one of the cells, selecting access points of the cell to provide one of said plurality of services to the UE. Optionally, the access points of the cell to provide the service to the UE are updated with mobility of the UE. Optionally, each randomization sequence or scheme is associated with a respective randomization ID. Optionally, the randomization ID is a cell ID, and transmitting and/or receiving within the cell using the respective randomization sequence or scheme involves randomizing a bit sequence using the cell ID in a transmitter by performing bitwise exclusive or to the bit sequence before modulation with a pseudo-random sequence generated or associated with the cell ID. Optionally, the method also includes in each cell, transmitting by each access point of the cell a synchronization sequence of the cell for initial access, wherein the randomization sequence or scheme of the cell is associated with the synchronization sequence. Optionally, a mapping or other relationship is maintained between a cell ID for each cell and a corresponding synchronization sequence. In each cell access points in the cell transmit the corresponding synchronization sequence for the cell. Transmitting and/or receiving within the cell using the randomization sequence comprises transmitting and/or receiving using a randomization sequence or scheme associated with or generated with the cell ID. Optionally, for at least one access point that is a member of two or more cells, the method involves for each of the two or more cells making transmissions/receptions using the respective randomization sequence or scheme. Optionally, for an access point that is a member of two or more cells providing different services, for each cell of the two or more cells, the access point makes transmissions and/or receptions using the respective randomization sequence or scheme of the cell and using a respective air interface configuration. Optionally a different randomization sequence is used for uplink and downlink transmissions to a UE. Optionally, the randomization sequence for downlink transmission is mapped to a synchronization sequence, and wherein there is also a pre-defined relationship between the downlink randomization sequence and the uplink randomization sequence. Optionally, the randomization ID is a cell ID, each cell ID belongs to one or more of a plurality of different sets of cell IDs that are pre-defined or indicated by signaling, each set of cell IDs associated with a characteristic, such use of a cell ID of a given set indicates the associated characteristic.
Another broad aspect of the invention provides a method in an access point or a user equipment, the method comprising on a single carrier frequency or on a set of aggregated carriers composed of one primary component carrier and at least one secondary component carrier, transmitting or receiving using at least two different air interface configurations, and for each air interface configuration using a different randomization sequence or scheme.
Another broad aspect of the invention provides a method in a user equipment. The method involves for each of a plurality of services, transmitting to and/or receiving from a respective cell using a respective randomization sequence or scheme. Optionally, for each of a plurality of services, transmitting to and/or receiving from a respective cell using a respective randomization sequence or scheme comprises one or a combination of: transmitting to and/or receiving from a first cell using a first randomization sequence or scheme for an eMBB service; transmitting to and/or receiving from a second cell using a first randomization sequence or scheme for an V2X service; transmitting to and/or receiving from a third cell using a second randomization sequence or scheme for an mMTC service; and transmitting to and/or receiving from a fourth cell using a fourth randomization sequence or scheme for an URLLC service. Optionally, transmitting and/or receiving using the respective randomization sequence or scheme comprises using the respective randomization sequence for one or a combination of: broadcast channel; control channel; data channel; other physical channels; and downlink and/or uplink physical channels.
Optionally, each randomization sequence or scheme is associated with a respective randomization ID. Optionally, the randomization ID is a cell ID, and wherein transmitting and/or receiving within the cell using the respective randomization sequence or scheme comprises randomizing a bit sequence using the cell ID in a transmitter by performing bitwise exclusive or to the bit sequence before modulation with a pseudo-random sequence generated or associated with the cell ID. Optionally, the method further includes during initial access in a cell, receiving a synchronization sequence of the cell; and determining the randomization sequence or scheme of the cell from the synchronization sequence. Optionally, for at least one of the plurality of services, a different randomization sequence is used for each of uplink and downlink transmissions. Optionally, the randomization ID is a cell ID, the method further involves receiving signaling information that associates each of a plurality of sets of cell IDs with a respective characteristic; and for at least one cell, the UE determining the characteristic of the cell from the cell ID of the cell and the signaled information. Optionally, the method involves for each of the plurality of services, transmitting to and/or receiving from the respective cell using the respective randomization sequence or scheme using a respective air interface configuration on a per service basis.
An embodiment solves the interference issue in a fundamental way by removing the cell boundary to go from cellular to non-cellular, as shown in the example of FIG. 14. FIG. 14 is a diagram that illustrates a conversion from a cellular system 300 to an embodiment non-cellular system 310. The cellular system 300 includes a plurality of a TPs 304 each with an associated cell 302. Each UE 306 connects only with the TP 304 within the cell 302 in which the UE 306 is located. Although the UE 306 can receive data signals from more than one TP, the control signals to the UE 306 can only come from the serving TP 304 within the cell 302 in which the UE 306 is located.
Non-cellular system 310 includes a plurality of TPs 304, UEs, 306, and a cloud processor 308. As used herein, the term TP may also be referred to as an access point (AP) and the two terms may be used interchangeably throughout this disclosure. The TPs 304 may include any component capable of providing wireless access by establishing uplink and/or downlink connections with the UEs 306, such as a base transceiver station (BTS), a NodeB, an enhanced NodeB (eNB), a femtocell, and other wirelessly enabled devices. The UEs 306 may comprise any component capable of establishing a wireless connection with the TPs 304. The TPs 304 may be connected to the cloud processor via a backhaul network (not shown). The backhaul network may be any component or collection of components that allow data to be exchanged between the TPs 304 and the cloud processor 308 and/or a remote end (not shown). In some embodiments, the network 100 may comprise various other wireless devices, such as relays, femtocells, etc. The cloud processor may be any type of data processing system capable of performing the processes disclosed below and capable of communication with other devices.
In non-cellular system 310, the TPs 304 are not associated with a cell. The system 310 includes a cloud processor 308 which organizes the TPs 304 into logical entities. Each UE 306 is assigned to a logical entity and is assigned a unique UE dedicated connection ID. In an embodiment, the UE can be a mobile phone, a sensor, a smart phone, or other wireless device. The UE 306 may move freely within an area serviced by a single logical entity without acquiring a new UE dedicated connection ID. Each TP 304 monitors signal strengths for any UE 306 detectable by the TP 304 and sends this data to the cloud processor 308. The cloud processor creates a logical entity or determines the identity of a logical entity to be assigned to serve each UE according to the measured signal strengths measured by the TPs 304. This determination can be performed dynamically in some embodiments. The cloud processor 308 assigns a logical entity ID to the logical entity and assigns a UE dedicated connection ID to each UE 306 according to the logical entity ID to which the UE 306 is assigned and the UE ID of the UE 306. In an embodiment, the UE 306 obtains the logical entity ID from the network and generates a dedicated connection ID from the logical entity ID and the UE ID. In this scenario, the network does not need to assign a UE dedicated connection ID to the UE 306. However, in either case, the communication between the UE 306 and the network is based on the dedicated connection ID. This UE dedicated connection ID is used by the UE when transmitting and receiving. The cloud processor 308 selects one of the TPs 304 from the group of TPs 304 in the logical entity to provide radio access to the UE 306 based on its dedicated connection ID. In an embodiment, the cloud processor 308 selects the TP 304 based on relative signal strengths of the UE 306 at each of the TPs 304 in the logical entity and/or the loads of each TP 304 in the logical entity. In other embodiments, other selection criteria can be utilized. In an embodiment, the cloud processor 308 dynamically reassigns a new TP 304 in the logical entity to serve the UE 306 based on changes to the signal strength of the UE at each TP 304 in the logical entity. The change in signal strength may be due to UE mobility or to other factors.
In an embodiment, the cloud processor 308 can enable or disable one or more TPs 304 covered by a logical entity to reach a substantially best trade-off between the service quality provided to all covered UEs 306 and energy saving criteria.
In an embodiment, the cloud processor 308 determines the TPs 304 to be assigned to a logical entity based on the geographic location of the TPs 304. In another embodiment, the cloud processor 308 determines the TPs 304 to be assigned to a logical entity based on the user distribution, application types and traffic loads.
In an embodiment, the TPs 304 assigned to a logical entity may be changed dynamically by the cloud processor 308 according to changes in network conditions. For example, at times of low radio access network utilization, some of the TPs 304 may be powered down to conserve power. At times of higher network utilization, more TPs 304 may be powered up in order to more efficiently serve the UEs 306 in the area and reduce congestion.
In an embodiment, the TPs 304 assigned to a logical entity may be enabled/disabled (e.g., powered on or off) in a distributed manner as determined by a TP's 304 measurement of certain parameters (e.g., UEs 306 covered by the TP) and the communications between TPs 304. Determining which TP 304 should be turned on or off could depend on various factors such as, for example, the UE 306 and TP 304 association relationship, UE 306 distribution, the Quality of Service (QoS) required, energy saving, etc.
FIG. 15A is a diagram illustrating an embodiment of a radio access system based on hyper cells. Shown is a hyper cell manager 140 and a number of TRPs 100,102, . . . , 134. The hyper cell manager 140 is connected to the TRPs through a backhaul network, not shown. The hyper cell manager 140 is responsible for configuring the TRPs into hyper cells. This can be done on a static or dynamic basis. More generally, given a coverage area with a plurality of TRPs, one or more hyper cells can be configured, each containing one or more TRPs. The number of TRPs, and the configuration of the TRPs into hyper cells is implementation specific. The coverage of the hyper cell may be equivalent to the coverage area provided by the combination of TRPs in the hyper cell.
Alternatively, the coverage area defined by a hyper cell includes an area that is smaller than all the coverage area provided by the combination of TRPs in the hyper cells. In some embodiments, the TRPs provide radio frequency (RF) functionality, while one or more base band units (BBUs) forming a BBU pool provide base band functionality. The BBU pool may be centralized or distributed. For example, it may be realized using virtualized calculation resources in an eNB with minimum total distance to all related TRPs. For the purpose of the examples, reference is made to TRPs. However, any of the embodiments described herein apply to access points generally.
A radio access network slice is a set of network resources and/or network functions allocated for a set of services. The set of services may be a service for one UE, a type of service for multiple UEs, multiple types of services for multiple UEs, or multiple types of services for one UE. The set of services may be dedicated to an operator, or shared among multiple operators. However, alternatively, network resources can be allocated directly to a service or services.
The same type of services may be provided by one or multiple slices. Multiple slices may be needed when isolation is needed among multiple operators or service providers.
Throughout this description, where “service/slice” is used, this is intended to encompass both embodiments specific to services and embodiments specific to slices. Methods and systems provide for hyper cells, the configuration of hyper cells, the operation of hyper cells, in a service specific manner and/or a slice specific manner.
Multiple (overlapping) hyper cells may coexist in the network to meet the requirements of various types of services/slices. Typically, different UEs may use different services in different hyper cells. In some cases, one UE may also use multiple services/slices supported by different hyper cells. In some embodiments, one UE may use one service/slice supported by different hyper cells in the downlink (DL) and uplink (UL) because the interference situation, link budget and traffic load for DL and UL may be quite different. Such coexistence of multiple hyper cells may be in a single carrier or in multiple carriers.
In some embodiments, some different services/slices are provided by the same hyper cells. This would be reasonable if the services/slices have similar requirements to TRP set configurations or if the network can only support a limited number of types of hyper cells.
In some embodiments, the same type of services/slices is provided by different hyper cells (possibly with overlapping coverage) for different UEs. This may be needed for UE centric hyper cells which are not only service specific but also UE specific.
Typically, different TRP sets may be associated to different hyper cells. However, different hyper cells may also be supported by the same TRP set. For example, a TRP set may use high frequency for a hyper cell with small coverage for eMBB services and meanwhile use low frequency for a hyper cell with larger coverage for URLLC services.
Configurations of TRPs for a Hyper Cell for a Service/Slice
In some embodiments, different sets of TRPs are defined for different hyper cells to fit the requirements of different services/slices.
In a first example, a set of TRPs may be defined for a hyper cell to provide eMBB services. eMBB services require high data rates, in particular for DL transmissions. It is preferred to provide such services in high frequency bands where large bandwidth is available to support high throughput. Since the coverage of a high frequency band is usually small, such eMBB services may be provided mainly by hyper cells with small coverage. Therefore sets of low power nodes (LPN) working in high frequency bands may be used for eMBB hyper cells.
In a second example, a set of TRPs may be defined for a hyper cell to provide V2X services. V2X services require high mobility. It is preferred to provide such service in a hyper cell with a large coverage area so that frequent handover or mobility management can be avoided. Therefore a large number of high power nodes (HPN) may be used for V2X hyper cells.
In a third example, a set of TRPs may be defined for a hyper cell to provide mMTC services. mMTC services require large connections for low power devices, mostly for UL small packet transmissions. It is preferred to provide such services in low frequency bands for good link budget so that those low power devices can access the network no matter where they are. For best UL performance, the closest TRPs may be used to support such mMTC services. They may be either HPNs or LPNs working in low frequency band.
In a fourth example, a set of TRPs may be defined for a hyper cell to provide URLLC services. URLLC services require high reliability and low latency. It is preferred to provide such services in low frequency bands for high reliability. TRPs with fast backhaul support should be used for URLLC hyper cells.
Combining the first through fourth examples, from a set of TRPs, a first set is defined for eMBB, a second set is defined for V2X, a third set is defined for mMTC, and a fourth set is defined for URLLC. The sets do not need to be distinct. A TRP belonging to multiple hyper cells in this example would be used to deliver the corresponding multiple services.
In some embodiments, a controller (for example hyper cell controller 150 of FIG. 15A) in the network determines the configurations of TRPs for a hyper cell and send messages to related TRPs or to the base band unit (BBU) pool for these TRPs and/or gateway (GW) to configure the hyper cell. Such a configuration message may include one or a combination of a hyper cell Identifier (ID) (equivalently a cell ID), slice ID, service ID, TRP set ID, access point set ID, or any other ID to identify the hyper cell. It may also include a list (for example identifiers) of the related TRPs and/or GW. It may also include some hyper cell ID information (e.g., carrier frequency, wireless resource, Numerology, etc.) for the hyper cell. In a specific example, the message may have the following format:

- Hyper cell config(hyper cell ID, N_TRP, TRP_IDi for i=1, N_TRP, service_ID)

Where hyper cell ID is an identifier of the hyper cell, N_TRP is the number of TRPS, and TRP_Idi is an identifier for the ith TRP, service_ID is a service identifier. For example, to configure a hyper cell having hyper cell ID 55 with 6 TRPs having identifiers 5, 2, 4, 6, 8, 10 to provide eMBB service having service_ID=1, the following message could be used:

- Hyper cell config (55, 5, 2, 4, 6, 8, 10, 1)

This controller may be realized as a function in a network entity (e.g. MME or RNC).
In some embodiments, the hyper cell controller takes into consideration load balancing among adjacent hyper cells when configuring a hyper cell.
An example configuration of the TRPs of FIG. 15A is depicted in FIG. 15B for providing an eMBB service. Here, the TRPs labelled “A” are included in a first eMBB hyper cells and the TRPs labelled “B” are included in a second eMBB hyper cell. There is a transparent boundary between the coverage of neighboring hyper cells 136,138. Also shown is a UE 135 that is within the coverage areas of both hyper cells 136,138. The system supports seamless UE mobility. While receiving service from hyper cell 136, the UE 135 can communicate with one or more TRPs of hyper cell 136. At a later time, due to mobility of the UE 135 can change to receiving service from hyper cell 138 and can communicate with one or more TRPs of hyper cell 138.
A system comprising the hyper cell manager 140 covers multiple logical entities (not shown). Each logical entity include a plurality of TPs. One skilled in the art will appreciate that it is possible in some embodiments for a logical entity to only include a single TP. There is a transparent boundary between the coverage of neighboring logical entities. The system supports seamless UE mobility, where the UE 135 use the latest received logical entity ID, e.g. cell ID. The UE 135 is within the coverage area of logical entity serving cell 136 and to logical entity serving cell 138. A hyper cell 136, 138 defines a coverage area provided by a corresponding logical entity. In an embodiment, the coverage area defined by the hyper cell 136, 138 is equivalent to the coverage area provided by the combination of TPs in the logical entity corresponding to the hyper cell 136, 138. In an embodiment, the coverage area defined by the hyper cell 136,138 includes an area that is smaller than all the coverage area provided by the combination of TPs corresponding to the hyper cell 136,138. An embodiment provides a wireless network free from traditional inter-cell interference. An embodiment provides higher spectrum efficiency, higher network capacity, a fairer UE experience, and lower energy consumption. Embodiments may be implemented in wireless networks, such as a fifth generation (5G) wireless network and the like.
An example configuration of the TRPs of FIG. 15A is depicted in FIG. 15C for providing a V2X service. Here, the TRPs labelled “C” are included in are included a hyper cell 140. The configurations of FIGS. 15B and 15C can occur simultaneously in a single combined example, in which case certain TRPs 100,106,116 are included in both eMBB hyper cell 136 V2X hyper cell 140, and certain TRPs 120,126,130 are included in both eMBB hyper cell 138 and V2X hyper cell 140.
Configuration of TRPs for a UE in a Hyper Cell
From the UE perspective, the fact that a hyper cell contains one or multiple TRPs is transparent. As such, herein, a hyper cell is also referred to simply as a cell, but such a cell can contain one or multiple TRPs. A UE can communicate with the hyper cell using the hyper cell ID. In some embodiments, it is at the option of the network which TRPs in a hyper cell participate in communications with a given UE. For different UEs being serviced by a hyper cell having a set of TRPs, different subsets of the set of TRPs may be used to optimize the performance of the service for each UE. For example, TRPs that are closely located to a UE or have good wireless channel quality may be selected to serve the UE.
In some embodiments, the subset of TRPs serving a UE in a hyper cell is updated with mobility of a UE. An example is shown in FIG. 16. A UE at time t1 is indicated at 200 within the coverage area of a hyper cell 202. At time to, TRPs 204,206,208 are providing service to the UE 200. The UE at a later time t2 is indicated at 210. At time t1, TRPs 206,208,212,214 are providing service to the UE.
In some embodiments, a hyper cell controller in the network determines the configurations of TRPs for a UE in a hyper cell and sends messages to the TRPs to configure them. Such a configuration message may include a UE ID (e.g. RNTI) to identify the UE in the hyper cell. It may also include a hyper cell ID, slice ID, service ID, TRP set ID, or any other ID to identify the hyper cell. In a specific example, the message has the following format:

- Hyper cell UE config(hyper cell ID, UE_ID, N_TRP_UE, TRP_IDi for i=1, N_TRP_UE, service_ID)
- where hyper cell ID is an identifier of the hyper cell, UE_ID is an identifier of the UE, N_TRP_UE is the number of TRPs being selected to serve the UE within the hyper cell, and TRP_Idi is an identifier for the ith TRP, service_ID is a service identifier. For example, to configure a hyper cell having hyper cell ID 55 with 6 TRPs having identifiers 5, 2, 4, 6, 8, 10 to provide eMBB service using TRPS with identifiers 5, 2, 6 for a UE having a UE identifier 12345, for a service having service_ID=1, the following message could be used:
- Hyper cell UE config (55, 12345, 3, 5, 2, 6, 1)

It is not necessary to inform the UE of a change in the TRPs providing service to the UE as this is transparent to the UE. This controller may be realized as a function in a network element (e.g. eNB or BBU pool).
In some embodiments, when configuring TRPs for a UE in the hyper cell, the controller takes into consideration one or a combination of:

- measurement results for wireless channels between the UE and the TRPs
- resources and capabilities of the TRPs
- load balancing among TRPs in a hyper cell
- policy and charging rules for the UE, etc.,

Configuration of Randomization Sequence/Schemes for Hyper Cells

In order to alleviate the impact of interference among transmissions for different hyper cells, in some embodiments, the signals transmitted for (to or from) different hyper cells are randomized using different randomization sequences (or randomization schemes).
Such randomization may be applied to one or a combination of:

- broadcast channel;
- control channel;
- data channel;
- other physical channels; and
- DL and/or UL physical channels.

In order to distinguish different randomization sequences (or randomization schemes) for different hyper cells, an ID (identifier), index, or any other parameter is needed for each hyper cell. In the following, this parameter will be referred to as a randomization ID. The definition of the term randomization ID used herein should be understood as a parameter used in randomization or scrambling of signals transmitted in some physical channels in a hyper cell, wherein different randomization IDs lead to different randomization/scrambling sequences/schemes. In some embodiments, the randomization ID is the same as the hyper cell ID. In the following description, the randomization ID is the hyper cell ID, but it should be understood that a different ID could be used.
In some embodiments, signals are randomized using the hyper cell ID in a transmitter (uplink or downlink) by performing bitwise xor (exclusive or) to the bit sequences before modulation with a pseudo-random sequence generated or associated with the hyper cell ID.
In a specific example, the randomization may be realized by scrambling as follows:
d(i)=(b(i)+c(i))mod 2
where b(i) is a bit sequence before modulation, c(i) is a scrambling sequence and d(i) is the bit sequence after scrambling. The scrambling sequence c(i) may be a pseudo-random sequence generated using an initialization value c_initwhich is a function of the hyper cell ID, e.g.
c _init =n _RNTI·2¹⁴ +q·2¹³ +└n _s/2┘·2⁹ +N _ID ^cell

- where q is the index of the codeword to be transmitted, ns is the slot number within a radio frame, n_RNTIis the RNTI associated with the data transmissions and N_ID ^cellis the hyper cell ID (=the randomization ID).

At the receiver, the same scrambling sequence can be generated using the hyper cell ID. This sequence can then be used for de-scrambling the bit sequence after demodulation so as to recover the desired bits while at the same time randomizing the interference introduced by signals from other cells in the DL or from UEs transmitting to other cells in the UL.
This hyper cell ID will be used by a UE for decoding desired signals in DL physical channels and/or transmitting signals in UL physical channels.
This hyper cell ID should be known by a UE before it can decode the randomized/scrambled broadcast signals, control signaling and/or data in the cell. In some embodiments, this is realized by pre-defining a mapping relationship between hyper cell IDs and synchronization sequences. All the TRPs of a hyper cell transmit the same synchronization sequence.
At initial access, the UE searches all the candidate synchronization sequences in a synchronization channel (SYNC channel). Upon successful decoding of a candidate sequence, the UE knows the exact sequence transmitted and then it can derive the hyper cell ID accordingly based on the pre-defined mapping.
Coexistence of Multiple Hyper Cell IDs for Different Hyper Cells
To support multiple (overlapping) hyper cells for various services/slices, multiple hyper cell IDs may be supported in a carrier (or multiple carriers).
In some embodiments, one hyper cell may be consisted of multiple types of TRPs which can operate in different spectrum ranges, with different transmit powers and/or different coverage ranges. In this case, the multiple types of TRPs operating in the same hyper cell will have the same hyper cell ID.
The same hyper cell ID may be used for multiple services/slices or self-contained air interface (AI) partitions in a carrier, for multiple carriers, or for different frequency ranges (e.g. both high frequency and low frequency bands). This is achieved by using the same TRP set for the multiple services/slices and thus they may use the same randomization sequence to address similar interference situations.
One TRP may be involved in multiple hyper cells and thus will transmit and/or receive signals using multiple hyper cell IDs on the same or different carrier frequencies. Signals for each cell ID will be randomized using the respective randomization sequence or scheme. As detailed below, in some embodiments there is a respective air interface configuration in the TRP for each cell ID. An example of this is depicted in FIG. 17, where a TRP1 300 is involved in both Hyper Cell 1 302 and Hyper Cell 2 304. Therefore it may use two hyper cell IDs for transmissions in a carrier. For this embodiment, if hyper cell IDs have corresponding synchronization sequences, TRP1 300 would transmit two synchronization sequences.
Returning to the combined example of FIGS. 15B and 15C, in a specific implementation the labels “A”, “B”, and “C” represent hyper cell IDs associated with randomization sequences/schemes. For eMBB, randomization sequence/scheme associated with hyper cell ID “A” is used in hyper cell 136, and randomization sequence/scheme associated with hyper cell ID “B” is used in hyper cell 138. For V2X, randomization sequence/scheme associated with hyper cell ID “C” is used in hyper cell 140. It can be seen that TRPs 100,106,116 operate with both hyper cell IDs “A” and “C”, while TRPs 120,126,130 operate with both hyper cell IDs “B” and “C”.
In some embodiments, the TRPs are configured such that one UE is involved in multiple hyper cells for different services, e.g. one for mMTC and the other for eMBB. Therefore the UE may transmit and/or receive signals using multiple hyper cell IDs for different services. An example is depicted in FIG. 18 where a UE 450 is communicating with Hyper Cell 1 452 for mMTC, and is communicating with Hyper Cell 2 454 for eMBB.
In some embodiments, a common hyper cell ID is used for uplink and downlink transmissions. There may be one common TRP set (some or all of the TRPS within a hyper cell) for both UL and DL for a service to a UE. Alternatively, there may be two different TRP sets (within a set of TRPs of a hyper cell) for UL and DL for a service to a UE. In either case, a common hyper cell ID may be used for both UL and DL if the wireless resources for UL and DL transmissions are isolated from each other and thus there is no interference between UL and DL transmissions.
In some embodiments, two different hyper cell IDs may be used for UL and DL for a service to a UE, respectively. An example is depicted in FIG. 19 which shows a UE 500 involved in hyper cell 502 for DL communications, and involved in hyper cell 504 for UL communications, and thus will use different hyper cell IDs for UL and DL.
In some embodiments, when different hyper cell IDs are used for UL and DL for a service to a UE, the DL hyper cell ID may be mapped to the synchronization sequence as described previously, while the UL hyper cell ID may be allocated to the UE by DL signaling. Alternatively, a pre-defined mapping relationship between DL hyper cell IDs and UL hyper cell IDs is established, such that the UE can derive the UL hyper cell ID from the DL hyper cell ID.
Configuration of Hyper Cell IDs for Different Services
In some embodiments, different sets of hyper cell IDs may be pre-defined (e.g., by standards) or indicated by signaling (e.g., by broadcasting) for various purposes, for example for different services, different AI slices or configurations.
Table 1 illustrates an example of such a pre-defined table for allocations of hyper cell IDs among services and/or their corresponding hyper cell IDs.

TABLE 1

Mapping between hyper cell IDs and Service/AI Configuration

Hyper cell ID	Service	AI Configuration

0~511	URLLC	AI configuration	1
512~1023	V2X	AI configuration	2
1024~2047	eMBB	AI configuration	3
2048~4095	mMTC	AI configuration	4

In some embodiments, different synchronization signals (or sequences) are generated from different hyper cell IDs.
A UE may search for all the candidate synchronization signals in a SYNC channel. When the UE successfully decodes one, the UE can determine the hyper cell ID used for the hyper cell and may then derive the service supported by the hyper cell and/or the hyper cell ID used for the hyper cell.
In some embodiments, if a UE has capabilities for certain services, it may only search for those candidate synchronization signals associated to those certain services. For example, again using the data from Table 1 above, URLLC devices may only need to search for the synchronization sequences corresponding to hyper cell IDs 0˜512.
In some embodiments, if a UE can only support some of the hyper cell IDs, the UE may only search for those candidate synchronization signals associated to its supported AI configurations. For example, again using the data from Table 1 above, mMTC devices that only support AI configuration 4 may only need to search for the synchronization sequences corresponding to hyper cell IDs 2048˜4095.
In some embodiments, the sets of hyper cell IDs for some services or AI configurations may overlap to support reuse of hyper cell IDs. In some embodiments, one set of hyper cell IDs may indicate multiple services or AI configurations. An example of this is provided in Table 2 below.

TABLE 2

Hyper cell IDs Indicating Multiple Services/AI Configurations

Hyper cell ID	Services Supported	AI Configuration

0~499	Basic Services Only	AI configuration 0
500~999	Basic + eMBB	AI configurations	0 & 2
1000~1999	URLLC + mMTC	AI configurations	0 & 1 & 3
2000~2999	All Services	AI configurations	0 & 1 & 2 & 3
3000~4095	Basic + Flexibly	AI configuration 0 + Flexibly
	Configured	configured

When multiple services are provided in a carrier, the wireless resources for different services may be indicated by broadcast (e.g., RRC) signaling or be determined according to the services supported, system bandwidth, frequency band, etc.
In another embodiment, a number of hyper cell IDs for some other (e.g., overlapping or adjacent) hyper cells are indicated by, for example by broadcast, multicast or unicast signaling or messages transmitted to UE in a hyper cell. The services supported or the AI configurations used in these hyper cells corresponding to these hyper cell IDs may also be indicated in the same signaling or in other signaling.
For example, a UE may access the network (search for the hyper cell ID in a default SYNC channel) using a pre-defined set of hyper cell IDs supporting basic access services and then obtain further information in the broadcast channel, control channel or other physical channels, typically scrambled by a sequence generated from the hyper cell ID used in the default SYNC channel about services or AI configurations of other hyper cells and their corresponding hyper cell IDs.
Configuration of AIs for Hyper Cells
Different hyper cells may have different coverage areas and experience different interference. To address this, AI configurations and methods of configuring AIs are provided that address these differences between hyper cells.

First AI Configuration Example: Cyclic Prefix (CP) Configuration

In some embodiments, multiple CP lengths for different slices/services may coexist in a carrier or in multiple carriers. For example, hyper cells with different hyper cell coverage may be assigned different CP lengths in the AI.
For hyper cells with small coverage, e.g., LPNs using HF for eMBB services, the delay spread of the wireless channel is expected to be small. Therefore a small CP length would be enough to avoid the inter symbol interference in the AI.
For hyper cells with large coverage, e.g., HPNs using LF for URLLC or mMTC services, the delay spread of the wireless channel would be large. Therefore a large CP length may be needed.
For hyper cells with normal coverage, a normal CP length would be reasonable.

Second AI Configuration Example: Timing Advance (TA) Measurement Configuration

In some embodiments, multiple TAs for different slices/services may coexist in a carrier or in multiple carriers. For example, hyper cells with different hyper cell coverage may be assigned different TAs in the AI.
For a hyper cell with small coverage, the RTDs (round trip delay) between the TRPs and the UE would be very small, even negligible. In this case, TA measurement may be unnecessary.
For a hyper cell with normal coverage, TA measurement similar to LTE may be applied.
For a hyper cell with large coverage, the UE may send a long preamble with large time duration to reach TRPs far away.
If the UE only needs to transmit small packets occasionally, it may use grant-free transmissions without sending signals for TA measurement.
When TA measurement is needed by multiple hyper cells for a UE, a common UL preamble may be used for TA measurement by all the interested TRPs in those hyper cells. Typically, this common preamble can be the one used in the hyper cell with largest coverage for the UE.

Third AI Configuration Example: SYNC Channel Configuration

In conventional systems, usually, only one SYNC channel is supported in a carrier, and adjacent cells use different SYNC sequences to transmit SYNC signals in the SYNC channel.
To support multiple (overlapping) hyper cells for various services, multiple SYNC channels may be supported in a carrier (or multiple carriers).
In one embodiment, wireless resources for multiple SYNC channels are pre-defined (e.g., in standards) in a carrier for various purposes, for example for one or more of:

- different services
- AI slices
- self-contained AI partitions

In some embodiments, when a UE needs a service, the UE first searches for the candidate synchronization sequences in the SYNC channel for that service, then decodes the broadcast channel and DL control channel to get necessary information for its transmissions. A signal transmitted in at least one of the broadcast channel, physical control channel and physical data channels is randomized or scrambled using the hyper cell ID corresponding to the SYNC signal transmitted in the SYNC channel.
FIG. 20-22 are three examples where multiple SYNC channels coexist in a carrier. For the purpose of these examples, the system bandwidth is divided into K sub-bandwidths and there may be a SYNC channel in each sub-bandwidth.
In the examples of FIG. 20 and FIG. 21, the SYNC channels have similar structure but are in different locations in the frequency domain. In FIG. 20, the location of each SYNC channel is in the center of a sub-bandwidth. In FIG. 21, the location of each SYNC channel (including or except for the one in the center of the system bandwidth) is within the same distance to an edge of a sub-bandwidth.
In the example of FIG. 22, the SYNC channels may have different configurations (location and period in time, size of time-frequency resource, channel structure, Numerology such as subcarrier spacing, SYNC signals, etc.). These configurations may be pre-defined, for example according to one or a combination of service, slice, Numerology or AI configuration, sub-bandwidth or other system parameters. They may also be indicated by messages (e.g., RRC signaling) transmitted to UE. They may also be blind-detected.
The number and/or widths of the sub-bandwidths may be pre-defined as a function of system bandwidth, frequency band, frame structure type, etc., or a combination of one or more of these.
Table 3 illustrates an example of sub-bandwidths defined as a function of system bandwidth.

TABLE 3

Sub-bandwidths for Different System Bandwidth

System	Number of	Width of
Bandwidth (BW)	Sub-bandwidth (K)	Sub-bandwidth

BW <= 20 MHz	1	BW
20 MHz <	2	BW/2
BW <= 40 MHz
BW > 40 MHz	Floor	(BW − 20*K)/2 for the two
	{BW/20 MHz}	at edge of system band-
		width, 20 MHz for others

When multiple SYNC channels may coexist in a carrier, the network may transmit SYNC signals in all of the SYNC channels in a carrier or only in some of them. When a SYNC channel (or may be called a candidate SYNC channel or a search space for SYNC channel) is not used for transmission of SYNC signals, it may be used for other transmissions. It is also possible that there may be no (candidate SYNC channel) defined for some of the sub-bandwidths.
Such a scheme supporting multiple SYNC channels is beneficial to allow different types of UEs (esp. those manufactured only for special services) to get their services independently. This is especially beneficial to support low-cost devices for vertical applications.
Such a scheme is also beneficial to reuse limited SYNC sequences in different wireless resources to support more services. Such reuse can be flexibly extended, not limited by the number of SYNC sequence, as the types of services increase.
Such a scheme may also be beneficial to support dedicated DL synchronization for different hyper cells with different TRP configurations, which may have different local timing, time delay to UE, Doppler shift, etc.
Referring now to FIG. 23, an example embodiment of the hyper cell manager 150 of FIG. 15A will now be described. The hyper cell manager 150 is configured to create and manage multiple hyper cells by defining a TRP set 154 for each hyper cell. In some embodiments, where hyper cells are UE specific, there can be a UE set 156 for each hyper cell. Each hyper cell may have a unique allocation of RAN resources 158. The RAN resources may include, for example:

- wireless network time-frequency resources, and
- spatial resources based on the geographic placement of APs 154 associated with the hyper cell and based on the directionality of transmissions if advanced antenna technologies are applied.

In some embodiments, the hyper cell manager 150 also configures the air interface of the TRPs of each hyper cell as detailed above, as indicated by air interface configuration block 160. The air interface configuration 160 may control one or a combination of the above-discussed examples, namely, one or a combination of:

- Cyclic prefix;
- Timing advance;
- SYNC channel.

However, more generally, the air interface configuration block 160 can control one more air interface parameters on a per hyper cell basis.
In some embodiments, UEs have correspondingly configurable air interfaces. In some embodiments, where a UE is obtaining multiple services, the UE is configured to communicate on a single carrier with multiple cells each providing a respective service using a respective air interface configuration for each cell and the respective randomization sequence or scheme. The access points of the multiple cells providing the multiple services to the UE may be the same, completely different, or overlapping.
In some embodiments, a single carrier is used to provide the multiple services. A set of hyper cells provides each service and each hyper cell has a respective randomization sequence or scheme. An access point transmits and receives using the randomization sequence(s) or scheme(s) of the hyper cell (s) it belongs to.
In other embodiments, multiple carriers are used to provide one or a combination of services. In some embodiments, where multiple carriers are used, carrier aggregation is employed. With carrier aggregation, a UE can be allocated uplink and downlink resources on the aggregated resource consisting of two or more component carriers.
Each component carrier has a respective bandwidth. For example, each component carrier can have a bandwidth of 1.4, 3, 5, 10, 15 or 20 MHz. There may be a maximum of component carriers that can be aggregated, for example five, and this limits the maximum aggregated bandwidth (to 100 MHz for this example). The number of aggregated carriers can be different in the downlink and the uplink. The individual component carriers can also be of different bandwidths.
When carrier aggregation is used there are a number of serving cells, one for each component carrier. The coverage of the serving cells may differ, for example due to that component carriers on different frequency bands will experience different path loss. The RRC connection is only handled by one cell, the Primary serving cell, served by the Primary component carrier. The other component carriers are all referred to as Secondary component carriers, serving the Secondary serving cells.
Either on a single carrier, or on multiple carriers, or on multiple carriers with combined resources through carrier aggregation, multiple air interface configurations are used for corresponding multiple services, and a different randomization sequence/scheme is used for each service. In some embodiments each service is on its own carrier such that there is a different randomization scheme for each carrier. In other embodiments, a service may use the aggregated resources of multiple carriers. In this case, the same randomization sequence or scheme is used to for the service on the multiple carriers. Where more than one service uses a given carrier, multiple randomization sequences or schemes are used on that carrier. As in other embodiments, a respective air interface configuration can be used for each service.
For the purpose of hyper cells, an access point that transmits on multiple carriers can be viewed as multiple access points, one for each carrier frequency. Then, for a given hyper cell, each access point can be included or not. For example, consider a given access point that:
transmits using three carriers which include a low frequency (LF), medium frequency (MF) and high frequency (HF) carrier such that logically there three access points Access pointHF, Access pointMF, and Access pointHF;

- is part of a first hyper cell being used to provide a first service service_A, the first hyper cell having randomization sequence RS_A; and
- is part of a second hyper cell being used to provide a second service service_B, the second hyper cell having randomization sequence RS_B.

In a first example, service_A uses the LF carrier, and service_B uses the MF carrier. In this case, effectively Access pointLF is included in the first hyper cell and transmits and receives for the service_A on the LF carrier with RS_A, and Access pointMF is included in the second hyper cell and transmits and receives for the service_B on the MF carrier with RS_B.
In a second example, service_A uses the LF carrier and the MF carrier, and service_B uses the MF carrier and the HF carrier. In this case, effectively Access pointLF is included in the first hyper cell and transmits and receives for the service_A on the LF carrier with RS_A. Access pointMF is included in both the first hyper cell and the second hyper cell and transmits and receives for the service A on the MF carrier with RS A and transmits and receives for the service_B on the MF carrier with RS_B. Access pointHF is included in the second hyper cell and transmits and receives for the service_B on the HF carrier with RS_B.
In some of the embodiments described above, each cell uses a different randomization sequence or scheme. This may help address issues with the interference between different cells.
In some embodiments, frequency division multiplexing is employed to avoid inter cell interference for example by using different carriers or sub-bands in a carrier In this case, it is not necessary to use different randomization schemes for all the services/cells.
In some embodiments, frequency division multiplexing (FDM) is combined with the use of randomization sequences or schemes, such that to avoid interference between two services/slices, each service/slice has a different combination of frequency division multiplexed resource and randomization sequence or scheme. This gives the following three possibilities:

- the two services/slices may have the same FDM resource and different randomization sequences or schemes are used;
- the two services/slices may have different FDM resources and the same randomization sequences or schemes;
- the two services/slices may have different FDM resources and different randomization sequences or schemes.

Consider an example in a carrier with 20 MHz bandwidth for providing three services Service A, Service B, and Service C as follows:

- Service A: 0˜5 MHz for all cells;
- Service B: 5˜10 MHz for some cells, 5˜15 MHz for other cells;
- Service C: 10˜20 MHz for some cells, 15˜20 MHz for other cells.

A randomization scheme can be reused for service A in a cell and service B in an adjacent cell (due to FDM). A randomization scheme can be reused for service B in 5˜15 MHz in a cell and service C in 15˜20 MHz in an adjacent cell. Different randomization schemes have to be used for service B in 10˜20 MHz in a cell and service C in 15˜20 MHz in an adjacent cell since they are in overlapping sub-bands.
In another example consider the following bandwidth assignments:

- Service A: 0˜5 MHz for all the cells;
- Service B: 5˜10 MHz for all the cells; and
- Service C: 10˜20 MHz for all the cells.

In this case, a randomization sequence can be freely reused for Service A, B and C due to FDM.
FIG. 24 is a schematic diagram of an example simplified processing system 400, which may be used to implement the methods and systems disclosed herein, and the example methods described below. The UEs, access points, hyper cell managers may be implemented using the example processing system 400, or variations of the processing system 400. The processing system 400 may be a server or a mobile device, for example, or any suitable processing system. Other processing systems suitable for implementing examples described in the present disclosure may be used, which may include components different from those discussed below. Although FIG. 24 shows a single instance of each component, there may be multiple instances of each component in the processing system 400.
The processing system 400 may include one or more processing devices 405, such as a processor, a microprocessor, an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA), a dedicated logic circuitry, or combinations thereof. The processing system 400 may also include one or more input/output (I/O) interfaces 410, which may enable interfacing with one or more appropriate input devices 435 and/or output devices 440. The processing system 400 may include one or more network interfaces 415 for wired or wireless communication with a network (e.g., an intranet, the Internet, a P2P network, a WAN and/or a LAN) or other node. The network interfaces 415 may include wired links (e.g., Ethernet cable) and/or wireless links (e.g., one or more antennas) for intra-network and/or inter-network communications. The network interfaces 415 may provide wireless communication via one or more transmitters or transmit antennas and one or more receivers or receive antennas, for example. In this example, a single antenna 445 is shown, which may serve as both transmitter and receiver. However, in other examples there may be separate antennas for transmitting and receiving. The processing system 400 may also include one or more storage units 420, which may include a mass storage unit such as a solid state drive, a hard disk drive, a magnetic disk drive and/or an optical disk drive.
The processing system 400 may include one or more memories 425, which may include a volatile or non-volatile memory (e.g., a flash memory, a random access memory (RAM), and/or a read-only memory (ROM)). The non-transitory memories 425 may store instructions for execution by the processing devices 405, such as to carry out examples described in the present disclosure. The memories 425 may include other software instructions, such as for implementing an operating system and other applications/functions. In some examples, one or more data sets and/or modules may be provided by an external memory (e.g., an external drive in wired or wireless communication with the processing system 400) or may be provided by a transitory or non-transitory computer-readable medium. Examples of non-transitory computer readable media include a RAM, a ROM, an erasable programmable ROM (EPROM), an electrically erasable programmable ROM (EEPROM), a flash memory, a CD-ROM, or other portable memory storage.
There may be a bus 430 providing communication among components of the processing system 400. The bus 430 may be any suitable bus architecture including, for example, a memory bus, a peripheral bus or a video bus. In FIG. 2, the input devices 435 (e.g., a keyboard, a mouse, a microphone, a touchscreen, and/or a keypad) and output devices 440 (e.g., a display, a speaker and/or a printer) are shown as external to the processing system 400. In other examples, one or more of the input devices 435 and/or the output devices 440 may be included as a component of the processing system 400.
FIG. 25 is a flow chart illustrating a method for execution by the network system comprising UEs, access points and RAN controller/manager in accordance with disclosed embodiments. Based on the above description, the access network comprising one or more RAN controller/manager to manage multiple hyper cells providing multiple RAN slice showing in the step 2501, for example, grouping and manage the one or more first cell to provide an eMBB service; grouping and manage the one or more second cell to provide V2X service; grouping and manage the one or more third cell to provide mMTC service; grouping and manage the one or more fourth cell to provide URLLC service. In one aspect, the RAN controller/manager can manage all the cells to provide the above services, or the RAN controller/manager can separately divide multiple physical or virtual controller to manage one or multiple cells. In one configuration, the RAN controller can configure the physical or virtual TRPs in a dynamic or a pre-configured fashion, e.g. the RAN controller can dynamic adjust or select the TRPs to group a cell to provide the same service or different services, in this situation, the RAN controller perform the step 2507: the RAN controller sends a message to indicate change of the hyper cell.
In one configuration, one TRP is a member of two or more cells providing different services, for each cell of the two or more cells, the TRP performs transmissions and/or receptions using the respective randomization sequence or scheme of the cell and using a respective air interface configuration.
In one embodiment, the RAN controller maintains a mapping or other relationship between a cell ID for each cell and a corresponding synchronization sequence; for an example, in each cell, the TRPs in the cell maintain synchronization sequence, the relationship can dynamically receive from the RAN controller or pre-defined in the TRPs. In one embodiment, the RAN controller configures randomization sequence or scheme associated with or generated with the cell ID for each TRP. In details, each randomization sequence or scheme is associated with a respective randomization ID. In one configuration, the randomization ID is a cell ID, and wherein transmitting and/or receiving within the cell using the respective randomization sequence or scheme comprises. In another configuration, the randomization sequence or scheme of the cell is associated with the synchronization sequence. In one example, the TRP or the RAN controller can configure using a different randomization sequence for uplink and downlink transmissions to the UE. In more details, the randomization sequence for downlink transmission is mapped to a synchronization sequence, and wherein there is also a pre-defined relationship between the downlink randomization sequence and the uplink randomization sequence. In one embodiment, if the randomization ID is a cell ID, each cell ID belongs to one or more of a plurality of different sets of cell IDs that are pre-defined or indicated by signaling, each set of cell IDs associated with a characteristic, such use of a cell ID of a given set indicates the associated characteristic. In one embodiment, after the RAN controller selects a TRP for one or more cells to provide the same or different service, the RAN controller sends a message to indicate information of the hyper cell showing in step 2502, in more details, the controller selects a first group access points (APs) as a member of a first cell associated with a first RAN slice, and send a first message to the first group APs, wherein the first message indicates information of the first cell; selects a second group APs as a member of a second cell associated with a second RAN slice; and send a second message to the second group APs, wherein the second message indicates information of the second cell. The first and second information can be one or a combination of: cell Identifier (ID), slice ID, service ID, access point set ID, or any other ID to identify the cell, a list of the access points of one of the cells. The TPR obtains or selects a set of transmission parameters associated with the service associated with the cell. Then in the step 2503, the TPR sends synchronization signals for the UE in the cell.
In one embodiment, a UE can support one or more services, in the step 2504, when the UE initial accesses a hyper cell and searching the synchronization signals though search all the candidate synchronization signals in a SYNC channel. When the UE successfully decodes one, in step 2505, the UE obtains the hyper cell ID and obtains a set of transmission parameters associated with the RAN slice. Step 2506 involves wirelessly transmitting or receiving Data using a set of transmission parameters associated with the RAN slice.
While this invention has been described with reference to illustrative embodiments, this description is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the invention, will be apparent to persons skilled in the art upon reference to the description. It is therefore intended that the appended claims encompass any such modifications or embodiments.

Claims

What is claimed is:

1. A method comprising:

selecting, by a controller in an access network, a first group access points (APs) as a member of a first cell associated with a first RAN slice;

sending, by the controller, a first message to the first group APs, wherein the first message indicates information of the first cell;

selecting, by the controller, a second group APs as a member of a second cell associated with a second RAN slice; wherein the first RAN slice provides different service from the second RAN slice with different numerologies; and

sending, by the controller, a second message to the second group APs, wherein the second message indicates information of the second cell;

wherein each of the first and second message comprises one or a combination of: cell Identifier (ID), slice ID, service ID, access point set ID, or any other ID to identify the cell, or a list of the access points of one of the cells.

2. The method of claim 1 further comprising, before the sending the first message, selecting, by the controller, the first group APs and the second group APs to group different cells to provide one or more different RAN slices based on mobility of a user equipment.

3. The method of claim 1 further comprising, before the sending the first message, obtaining, by the controller, the information of the first and second cell associated with a randomization sequence or scheme for a respective cell.

4. The method of claim 3, wherein each randomization sequence or scheme is associated with a respective randomization ID.

5. The method of claim 4 wherein the randomization ID is a cell ID, the method further comprising:

randomizing, by the controller, a bit sequence using the cell ID; and

performing, by the controller, bitwise exclusive or to the bit sequence before modulation with a pseudo-random sequence generated or associated with the cell ID.

6. The method of claim 1, further comprising:

maintaining, by the controller, a mapping relationship between a cell ID for each cell and a synchronization sequence.

7. The method of claim 1, wherein the first cell and the second cell are hyper cells, and the hyper cells provide a wireless access for a coverage area with non-cellular grid among the APs, and wherein the coverage area serves a user equipment (UE) moving freely in the coverage area.

8. A controller in an access network comprising a plurality of access points (APs), comprising:

a non-transitory memory storage comprising instructions; and

one or more processors in communication with the non-transitory memory storage, wherein the one or more processors execute the instructions to:

select a first group access points (APs) as a member of a first cell associated with a first RAN slice, and send a first message to the first group APs, wherein the first message indicates information of the first cell; and

select a second group APs as a member of a second cell associated with a second RAN slice; and send a second message to the second group APs, wherein the second message indicates information of the second cell;

wherein the first RAN slice provides different service from the second RAN slice with different numerologies, and each of the first and second message comprises one or a combination of: cell Identifier (ID), slice ID, service ID, access point set ID, or any other ID to identify the cell, or a list of the access points of one of the cells.

9. The controller of claim 8, wherein the non-transient memory storage further stores instructions to obtain the information of the first and second cell associated with a randomization sequence or scheme for a respective cell.

10. The controller of claim 9, wherein each randomization sequence or scheme is associated with a respective randomization ID.

11. The controller of claim 8, wherein the non-transient memory storage further stores instructions to maintain a mapping relationship between a cell ID for each cell and a synchronization sequence.

12. A method comprising:

receiving, by an access point (AP), a first message from a controller, wherein the first message indicates information of a first cell grouping a first group access points (APs) associated with a first RAN slice; and

receiving, by the AP, a second message from the controller, wherein the second message indicates information of a second cell grouping a second group access points (APs) associated with a second RAN slice;

13. The method of claim 12, wherein the information of the cell is associated with a randomization sequence or scheme for a respective cell.

14. The method of claim 13, wherein each randomization sequence or scheme is associated with a respective randomization ID.

15. The method of claim 14, the method further comprises:

sending, by the AP, synchronization information to a user equipment (UE), wherein the synchronization information comprises a synchronization sequence, and the synchronization sequence is associated with the randomization sequence.

16. The method of claim 15, the method further comprising:

communicating, by the AP, uplink and downlink transmissions to the UE using a different randomization sequence for uplink and downlink transmissions.

17. The method of claim 16 wherein:

the randomization sequence for downlink transmission has a mapping relationship with the synchronization sequence, and the randomization sequence for downlink transmission has a pre-defined relationship with the randomization sequence for uplink transmission.

18. A network access point (AP), comprising:

a non-transitory memory storage comprising instructions; and

receive a first message from a controller, wherein the first message indicates information of a first cell grouping a first group access points (APs) associated with a first RAN slice; receive a second message from the controller, wherein the second message indicates information of a second cell grouping a second group access points (APs) associated with a second RAN slice;

wherein the first RAN slice provides different service from the second RAN slice with different numerologies, and each of the first and second message comprises one or a combination of: cell Identifier (ID), slice ID, service ID, access point set ID, or any other ID to identify the cell, or a list of the access points of one of the cell.

19. The AP of claim 18, wherein the information of the cell is associated with a randomization sequence or scheme for a respective cell.

20. The AP of claim 19, wherein each randomization sequence or scheme is associated with a respective randomization ID.

21. The AP of claim 20, wherein the non-transient memory storage further stores instructions to send synchronization information to a user equipment (UE), wherein the synchronization information comprises a synchronization sequence, and the synchronization sequence is associated with the randomization sequence.

22. A method in a user equipment (UE) comprising:

receiving, by the UE, a synchronization information from an access point (AP),

obtaining, by the UE, a cell ID of a cell associated with a RAN slice; and

sending, by the UE, data to the AP with a set of transmission parameters associated with the RAN slice, wherein the set of transmission parameters is one of the multiple sets of transmission parameters associated with multiple RAN slices.

23. The method of claim 22, the method further comprising:

decoding successfully, by the UE, a synchronization sequence from candidate synchronization signals; and

obtaining, by the UE, the cell ID based on a pre-defined relationship between the cell ID and the synchronization sequence.

24. The method of claim 23, wherein the synchronization sequence is associated with a randomization sequence, and the randomization sequence is associated with a respective cell ID.

25. The method of claim 23, the method further comprising:

receiving, by the UE, information from two APs serving to same or different RAN slice.

26. The method of claim 23, wherein the cell is hyper cell, and the hyper cell provides a wireless access for a coverage area with non-cellular grid among the APs, and wherein the coverage area serves a user equipment (UE) moving freely in the coverage area.

27. A User Equipment (UE) comprising:

a non-transitory memory storage comprising instructions; and

receive a synchronization information from an access point (AP);

obtain a cell ID of a cell associated with a RAN slice; and

send data to the AP with a set of transmission parameter associated with the RAN slice, wherein the set of transmission parameters is one of the multiple sets of transmission parameter associated with multiple RAN slices.

28. The UE of claim 27, wherein the non-transient memory storage further comprises instructions to:

decode successfully a synchronization sequence from candidate synchronization signals;

and obtain the cell ID based on a pre-defined relationship between the cell ID and the synchronization sequence.

29. The UE of claim 28, wherein the synchronization sequence is associated with a randomization sequence, and the randomization sequence is associated with a respective cell ID.

30. The UE of claim 28, wherein the cell is a hyper cell, wherein the hyper cell provides a wireless access for a coverage area with non-cellular grid among the APs, and wherein the coverage area serves a user equipment (UE) moving freely in the coverage area.