WO2017186308A1

WO2017186308A1 - Grouping manager and user equipments for a communication network

Info

Publication number: WO2017186308A1
Application number: PCT/EP2016/059659
Authority: WO
Inventors: Spapis PANAGIOTIS; Alexandros KALOXYLOS; Chan Zhou; Konstantinos CHATZIKOKOLAKIS; Nancy ALONISTIOTI
Original assignee: Huawei Technologies Co., Ltd.
Priority date: 2016-04-29
Filing date: 2016-04-29
Publication date: 2017-11-02

Abstract

The invention relates to a grouping manager for a communication network, the grouping manager comprising a receiver configured to receive device information about a plurality of devices in the communication network, a processor configured to assign at least one of the plurality of devices as group head or group member based on the received device information, a transmitter configured to transmit a notification information about the group assignment, wherein the device information comprise a transmission delay tolerance. The grouping manager can be realized as a standalone entity or as a mobility server or base station. The invention also relates to a communication method which comprises: receiving a group head notification information, receiving group member transmit data from a group member device that is assigned as group member, waiting until a local transmit data is available for transmission, and transmitting the group member transmit data and the local transmit data.

Description

GROUPING MANAGER AND USER EQUIPMENTS FOR A COMMUNICATION

NETWORK

TECHNICAL FIELD

The present invention relates to a grouping manager for a communication network and user equipments for the communication network. The present invention also relates to a method for determining a group head in a communication network and to a method for communicating in a communication network. Further, the present invention also relates to a computer-readable storage medium storing program code, the program code comprising instructions for carrying out the above methods. BACKGROUND

Past generation wireless cellular-based networks have been designed for human-to-human (H2H) and human-to-machine (H2M) communication services, e.g. telephony, SMS, streaming services etc. Even in current communication networks there is limited support for ma- chine -to-machine (M2M) applications. In particular, cases where a large number of machines attempt to periodically transmit small amounts of data are not well supported. Large numbers of devices often coexist in M2M scenarios and recent trends show that such applications will have increased penetration to wireless cellular-based networks. Particularly, it is expected that the number of M2M devices will increase in the future.

Group-based communication can be used in the context of machine-type communication devices or device-to-device communication, but can also be applied to any other wireless communication network. In order to cope with the stringent communication requirements of M2M devices and to increase the scalability of wireless cellular-based communication systems, novel methods that identify critical bottlenecks to the network performance and that offer solutions to avoid any operational issues for the Network Operator (e.g., QoS degradation) are required. One area that calls for improvements is the network access procedure that devices follow before data trans- mission/reception. Devices in the network follow the random access procedure so as to transmit or receive any data. This procedure is often implemented as a contention based random access process, where the devices are competing to access the network using a set of predefined, limited resources, the random access preambles.

In LTE networks this procedure is executed through the Random Access Channel, which has the capacity of 64 preambles per slot (or Random Access Opportunity, RAO). The number of RAOs per time frame depends on the eNB bandwidth capacity and the value may typically vary from 1 RAO/frame up to 5 RAOs/frame, while in extremely heavy loaded conditions, 20 RAOs/frame may be used. Each RAO typically allocates 6 Physical Resource Blocks (PRBs) on the frequency domain and 1 time slot equal to half subframe (i.e. 0.5 msec) on the time domain. The 6 PRBs carry 72 subcarriers (i.e. each PRB has 12 subcarriers), which, after the exclusion of guardbands, leave the possibility of successful decoding of up to 64 signals (i.e. the 64 preambles).

The procedure is typically conducted as follows:

• UE selects one of the 64 - N RACH preambles (where N are preambles used for contention free) and transmits the preamble based on the Zadoff-Chu (ZC) sequences

• UE decodes the physical dedicated control channel (PDCCH) with random access-radio network temporary identifier (RA-RNTI) in the random access response window to receive the random access response (RAR) message.

• UEs send the actual message for this random access procedure

• eNB acknowledges the successfully decoded L2/L3 message through contention resolution message. For a failed packet delivery, a new random access procedure is triggered

In case of collisions the devices attempt to retransmit a random access preamble after a short time period. In case of a large number of devices competing to access the network (as it is forecasted to occur in future networks) it is predicted that such contention based system access using random access preambles will be a bottleneck.

Wireless cellular-based communication devices follow the random access procedure to establish network connection and to send (or receive) data. For example, random access procedures in LTE/LTE-A networks typically occur once every 10ms, and during this a device randomly selects a specific pattern or signature (also known as preamble) out of the 64 available. In case two (or more) devices have selected the same pattern at the same time, a collision occurs and the devices attempt to resend a preamble after a short period. Consequently, network latency as well as battery consumption is increased due to retransmissions. SUMMARY OF THE INVENTION

The objective of the present invention is to provide a grouping manager, a user equipment and methods for a communication network, which overcome one or more of the above-mentioned problems of the prior art.

A first aspect of the invention provides a grouping manager for a communication network, the grouping manager comprising:

a receiver configured to receive device information about a plurality of devices in the communication network,

- a processor configured to assign at least one of the plurality of devices as group head or group member based on the received device information, and

a transmitter configured to transmit a notification information about the group assignment,

wherein the device information comprise a transmission delay tolerance.

The grouping manager of the first aspect can be configured to transmit the notification information to the plurality of devices. Thus, the devices can be informed about their group assignment. The transmission delay tolerance may comprise a duration between time point of availability of data for transmission and a time point of when the data need to be transmitted. In other embodiments, transmission delay tolerance may comprise other properties, e.g. the end of a transmission delay period, i.e., the latest point in time when data needs to be transmitted. The transmission delay tolerance may also comprise other indicators of a delay tolerance for a given transmission.

The grouping manager of the first aspect has the advantage that it can enable a communication network to setup one or more groups of devices, wherein in each group a group head is responsible for communicating with a base station of the communication network. In other words, the group head can act for the group members as a relay towards the base station, wherein the group members communicate with the base station only through the group head. Thus, the base station has to communicate only with a (small) number of group heads, and there is a much smaller risk of contention between devices in the communication network.

The grouping manager of the first aspect is of particular relevance for upstream communication of the plurality of devices, i.e., for communications initiated on the devices.

The grouping manager of the first aspect of the invention can use knowledge about service requirements that is available in advance (including but not limited to service type, service access periodicity, delay requirements, delay tolerance, application scenario, mobility information, etc.) for grouping devices and selecting a most appropriate group representative. Additionally, joint transmissions can be performed from the group representative for all the devices belonging in a group so as to reduce the number of devices competing for accessing the network.

The grouping manager provides mechanisms that solve the above-described challenges of the prior art by effectively reducing the number of devices that compete for RACH resources. In general, many devices such as sensors and actuators have periodic transmissions. In particular, the proposed grouping manager can be configured to group the devices by considering their transmission delay tolerances, but possibly also service requirements such as service access periodicity information, delay requirements, time synchronization of MTC transmissions etc., as well as other information types including but not limited to, radio measurements (such as RSS, RSRP, RSRQ, RSSI, CQI, etc.), location information, mobility, etc.

Further, additional parameters could be considered for the device grouping such as battery level of the device, processing capabilities, memory, etc. The devices can be grouped by a logically centralized entity which has information about the previous characteristics. Once a new device associates to the network, the centralized entity responsible for the grouping will identify which group of devices is more suitable for the new device and it will indicate to it that it should be placed in the corresponding group.

When a device belongs to a group as a grouping manager, it can communicate with the network through the group head. Instead of the term "group" one can also refer to a "cluster", and instead of "group head", one can also refer to a "group representative". These terms may be used interchangeably in the following.

In a preferred embodiment, once a device wants to transmit data, it provides this data to the group head and the group head aggregates the data from many group member and proceeds to one random access request for all the group members. When the network grants to it uplink resources, then it proceeds in transmission of all the aggregated data of the group members (and the data that the group head has produced).

A system based on the afore-described group based access can reduce the number of competing devices for the RACH resources. Additionally, since the devices are being grouped by considering their communication characteristics (e.g., scheduling information, delay requirements, service access periodicity, time synchronization of MTC transmissions etc.) as well as other information types (e.g., location information, mobility, etc.) it is ensured that the devices are being prioritized based on their service requirements and only the devices with stringent delay requirements are competing for RACH resources, thus resulting in a significantly reduced number of collisions.

In a first implementation of the grouping manager according to the first aspect, the processor is configured to assign the plurality of devices to a plurality of groups and to assign devices with overlapping transmission delay tolerance periods to a same group. The grouping manager according to the first implementation has the advantage that, by assigning devices with overlapping transmission delay tolerance periods to a same group, devices can be grouped together that can efficiently communicate with the base station through a common group head. This is based on the realization that devices can communicate through a common "relay" particularly efficiently if they have overlapping transmission delay tolerance periods.

A delay tolerance period of a device can be determined e.g. based on a data availability time t₀ (the point in time where a data is available for transmission) and a transmission delay tolerance At (e.g. the time in ms within which the data should be transmitted). In this case, the delay tolerance period is given by the time interval from t₀ to t₀+ t.

If there is more than one group, the grouping manager can be configured to assign a device as group head of its group if its transmission delay tolerance is lowest among the transmission delay tolerances of the devices of its group. For example, a first device with a transmission delay tolerance duration of 10 ms may be selected as group head if the other devices in the group have transmission delay tolerance durations of more than 10 ms. In a second implementation of the grouping manager according to the first aspect as such or according to the first implementation of the first aspect, the processor is configured to only assign mobile devices that are determined to have a periodic transmission.

Not assigning mobile devices that do not have a periodic transmission can be advantageous because these devices may have random times of data transmission. Thus, they cannot be grouped together for relay transmission in an efficient manner. The grouping manager may be configured to notify such devices about their non-grouping status, i.e., that they are neither group head nor group member. In a third implementation of the grouping manager according to the first aspect as such or according to any of the preceding implementations of the first aspect, the processor is configured to assign a device as group head if its transmission delay tolerance is lowest among the transmission delay tolerances of the plurality of devices. If there is more than one group, a device can be assigned as group head of its group if its transmission delay tolerance is lowest among the transmission delay tolerances of the devices of its group.

The grouping manager of the third implementation has the advantage that a device which has the lowest delay tolerance (i.e. the highest "urgency" to transmit its data) is assigned as group head. Experiments have shown that this results in a good efficiency of the communication network. In a fourth implementation of the grouping manager according to the third implementation of the first aspect, the processor is configured to, if two or more devices have a same minimum transmission delay tolerance, assign as group head a device with an earliest ending of a transmission delay tolerance period and/or assign as group head a device with a best signal quality measurement.

This provides an efficient rule for assigning a group head if more than one device have a same transmission delay tolerance, e.g. a same transmission delay tolerance duration. In a fifth implementation of the grouping manager according to the first aspect as such or according to any of the preceding implementations of the first aspect, the transmitter is further configured to transmit a transmission- wait message that instructs a device that is assigned as group head to wait with transmission, wherein in particular the transmission-wait message comprises a wait interval indication.

Because the grouping manager can be aware of the transmission periodicities of the different devices and of the transmission delay tolerances of the different devices, it can determine how long a group head needs to wait before receiving further transmission data from one of the group members of its group. The grouping manager can forward this information to the group head in the transmission-wait message.

The grouping manager can be configured to transmit the transmission-wait message to the group head every time that new data is available for transmission. In other embodiments, the grouping manager can be configured to transmit a transmission-wait messages which com- prises information about wait intervals for a plurality of future transmissions.

In a sixth implementation of the grouping manager according to the first aspect as such or according to any of the preceding implementations of the first aspect, the grouping manager further comprises a second receiver configured to receive at least a part of the device informa- tion from a node in the communication network that is not a user equipment, in particular from a subscriber server, in particular a home subscriber server, HSS.

Some of the device information may not be available at the user equipments, but rather at other nodes in the communication network. In particular, the information may be available at the subscriber server, e.g. the home subscriber server at an LTE network. Thus, it can be advantageous that the grouping manager is configured to receive the device information from such other nodes in the communication network. In a seventh implementation of the grouping manager according to the first aspect as such or according to any of the preceding implementations of the first aspect, the device information further comprises at least one of the following:

a network measurement, in particular at least one of the following: a received signal strength, an RSRP value, an RSRQ value, an interface information, a channel quality information, and a link quality;

a location and/or mobility information, in particular at least one of the following: a device position, a device speed, a number of handovers, and a device mobility pattern;

a service measurement, in particular at least one of the following: a service access periodicity, a data rate, a service type, and a time synchronization of data transmissions; and - a device description information, in particular at least one of the following: an available battery information, a maximum battery charging level, a device central processing unit description, a memory information, an operating system information, a screen size, a screen resolution, a power and/or energy information, a battery consumption rate, a battery level, a current CPU load level, a current memory load level, and an information about one or more protocols supported by the user equipment.

The further information that is available to the grouping manager of the seventh implementation has the advantage that the grouping manager can make a better decision about which device to assign as group head or group member. For example, if the device information com- prises a service type, the grouping manager can be configured to estimate delay tolerance periods based on assumptions about the devices or about the data to be transmitted. For example, the grouping manager might know that a certain device is transmitting smart grid emergency notifications and it can assume that a transmission delay tolerance for such data is low. Thus, this device is more likely selected as group head. In other cases, the grouping manager may know that the data to be transmitted from a certain device is related e.g. to email transmission, for which the transmission delay tolerance is high.

In other embodiments, the grouping manager may be configured to primarily determine the group head based on the transmission delay tolerances. However, if this is inconclusive, e.g. because many devices have the same transmission delay tolerances, the grouping manager may be configured to determine the group head based on the additional device information. For example, if two devices have a same transmission delay tolerance, the grouping manager may be configured to select that device as group head which has a highest battery level (and thus is least likely to fail due to low battery). Alternatively, the grouping manager may be configured to select the device as group head which has a lowest current CPU load level and/or lowest memory load level, and thus has most resources available for acting as a relay for other group members. In an eighth implementation of the grouping manager according to the first aspect as such or according to any of the preceding implementations of the first aspect, the transmitter is configured to transmit the notification information as part of an attach accept message.

Transmitting the notification information as part of the attach accept message has the advantage that the group assignment information is available to the plurality of devices immediately when they are being attached to a base station. Also, unnecessary exchange of (additional) messages is avoided.

In a ninth implementation of the grouping manager according to the first aspect as such or according to any of the preceding implementations of the first aspect, the grouping manager is a standalone entity, a mobility server, in particular a mobility management entity, MME, or a base station of the communication network.

Having the grouping manager as a standalone entity has the advantage that the grouping manager can easily be added to an existing network. Furthermore, one grouping manager can provide services to a plurality of base stations.

Having the grouping manager as a mobility management entity or a base station in the communication network has the advantage that no additional entity is required. In preferred em- bodiments, existing mobility management entities or base stations can be upgraded, e.g. via firmware upgrade, to include a grouping manager functionality. A second aspect of the invention refers to a user equipment for a communication network, the user equipment comprising a transmitter configured to transmit an accept request message that comprises a transmission delay tolerance and/or a periodicity information. The user equipment of the second aspect has the advantage that it can transmit the information to the grouping manager that the grouping manager, e.g. the grouping manager of the first aspect, requires to make its assignment of group head and group members.

A third aspect of the invention refers to a user equipment for a communication network, the user equipment comprising:

a first receiver configured to receive a group head notification information, a second receiver configured to receive group member transmit data from a group member device, and

a transmitter configured to transmit the group member transmit data and local transmit data when the local transmit data is available.

The first and the second receiver can be the same receiver, i.e., there is no requirement for two physically different receivers. The user equipment of the third aspect can wait for group member transmit data before transmitting both the local transmit data (e.g. originating from the user equipment itself) and the group member transmit data. This has the advantage that a number of transmissions from the user equipment to its base station can be reduced. A fourth aspect of the invention refers to a method for determining a group head from a plurality of devices in a communication network, the method comprising:

receiving device information,

assigning at least one of a plurality of devices as group head or group member based on the received device information, and

- transmitting a notification information about the group assignment,

wherein the device information comprise a transmission delay tolerance.

The method of the fourth aspect can be carried out by a grouping manager in the communication network, e.g. the grouping manager of the first aspect or one of its implementations. In a first implementation of the method according to the fourth aspect the method is carried out when a new device connects to a base station and/or when a group head disconnects from a base station.

This has the advantage that a new device can immediately be assigned to a group (e.g. as group member or group head).

It is understood that in the above, a group assignment can be specific to a certain base station.

A fifth aspect of the invention refers to a method for communicating in a wireless communication network, the method comprising:

receiving a group head notification information,

receiving group member transmit data from a group member device that is assigned as group member,

waiting until a local transmit data is available for transmission, and

transmitting the group member transmit data and the local transmit data.

The method of the fifth aspect of the invention can be carried out e.g. by the user equipment of the third aspect.

A further aspect of the invention relates to a system comprising a grouping manager of the first aspect and one or more user equipments according to the third aspect of the invention. A further aspect of the invention refers to a computer-readable storage medium storing program code, the program code comprising instructions for carrying out the method of the fourth aspect, one of the implementations of the fourth aspect or the method of the fifth aspect.

BRIEF DESCRIPTION OF THE DRAWINGS

To illustrate the technical features of embodiments of the present invention more clearly, the accompanying drawings provided for describing the embodiments are introduced briefly in the following. The accompanying drawings in the following description are merely some em- bodiments of the present invention, but modifications on these embodiments are possible without departing from the scope of the present invention as defined in the claims.

FIG. 1 is a block diagram illustrating a grouping manager in accordance with an em- bodiment of the present invention,

FIG. 2 is a block diagram illustrating a user equipment in accordance with a further embodiment of the present invention, FIG. 3 is a block diagram illustrating a user equipment in accordance with a further embodiment of the present invention,

FIG. 4 is a flow chart of a method for determining a group head from a plurality of devices in accordance with an embodiment of the present invention,

FIG. 5 is a flow chart of a method for communicating in a wireless communication network in accordance with a further embodiment of the present invention, is schematic illustration of a topology of a direct communication of devices within a communication network before the grouping, in accordance with a further embodiment of the present invention, is a schematic illustration of relay-based communication of devices with a communication network through a group head, after a grouping performed by the grouping manager, in accordance with a further embodiment of the present invention, is a flow chart of a method for grouping of the devices in accordance with a further embodiment of the present invention, is a time-diagram illustrating an exemplary implementation of mechanism for grouping by considering only the service requirements in accordance with a further embodiment of the present invention, FIG. 9 is a time-diagram illustrating a further exemplary implementation of mechanism for grouping by considering only the service requirements in accordance with a further embodiment of the present invention,

FIG. 10 is a flow chart of a method for incorporating newly deployed devices in the groups in accordance with a further embodiment of the present invention,

FIG. 11 is a sequence diagram of a method for setting up group-based communication for a newly attached device in an LTE/LTE-A network in accordance with a further embodiment of the present invention, and

FIG. 12 is a sequence diagram of a communication phase in accordance with a further embodiment of the present invention. Detailed Description of the Embodiments

FIG. 1 shows a schematic illustration of a grouping manager 100 for a communication network. The communication network can be e.g. an LTE or LTE-A network. It can also be a fifth generation communication network.

The grouping manager 100 comprises a receiver 1 10, a processor 120 and a transmitter 130.

The receiver 100 is configured to receive device information about a plurality of devices in the communication network. The plurality of devices may be wireless devices, e.g. user equipments.

The processor 120 is configured to assign at least one of the plurality of devices as group head or group member based on the received device information.

The transmitter 130 is configured to transmit a notification information about the group assignment, wherein the device information comprises a transmission delay tolerance. The notification information may e.g. be transmitted as part of a network attach message. The grouping manager 100 can be implemented as a logically centralized entity, which has knowledge of current network conditions and the requirements from the devices. The grouping manager can select a group representative who is responsible to access the network on behalf of all group members and transmit the data of all devices that comprise the group.

FIG. 2 is a schematic illustration of a first user equipment 200 for a communication network. The user equipment 200 may be configured to communicate (directly or indirectly) with the grouping manager 100 shown in FIG. 1.

The user equipment 200 comprises a transmitter 210 configured to transmit an accept request message that comprises a periodicity information and/or a transmission delay tolerance.

The user equipment 200 may optionally (indicated with a dashed lines) further comprise a receiver 220 configured to receive messages from a grouping manager 100.

FIG. 3 is a schematic illustration of a second user equipment 300 for a communication network.

The user equipment 300 comprises a first receiver 310, a second receiver 320 and a transmitter 330. The first receiver 310 and the second receiver 320 may be two physically separate devices, but in other embodiments may also be realized on one physical receiver.

The first receiver 310 is configured to receive a group head notification information. For example, the group head notification may be received from a grouping manager.

The second receiver 320 is configured to receive group member transmit data from a group member device. The group member device may be another user equipment in the same communication network.

The transmitter 330 is configured to transmit the group member transmit data and local transmit data when the local transmit data is available. For example, the transmitter 330 may be configured to transmit the group member transmit data and the local transmit data to a base station that the user equipment is attached to. FIG. 4 is a flow chart of a method 400 for determining a group head from a plurality of devices in a communication network. The method 400 may be performed e.g. by the grouping manager 100 shown in FIG. 1. The method 400 comprises a first step 410 of receiving device information. The device information comprises a transmission delay tolerance and may comprise further information about a user equipment.

The method comprises a second step 420 of assigning at least one of a plurality of devices as group head or group member based on the received device information. In particular, the assigning is based on the transmission delay tolerance.

The method comprises a third step 430 of transmitting a notification information about the group assignment. In particular, the notification information may be transmitted to the user equipment from which the device information were received.

FIG. 5 is a flow chart of a method 500 for communicating in a wireless communication network. The method comprises a first step 510 of receiving a group head notification information.

The method comprises a second step 520 of receiving group member transmit data from a group member device that is assigned as group member. The method comprises a third step 530 of waiting until a local transmit data is available for transmission. For example, the local transmit data may come from a sensor that is attached to the device.

The method comprises a fourth step of transmitting 540 the group member transmit data and the local transmit data.

Embodiments of the invention can be seen as operating in two phases: • An initialization phase: in this phase a newly deployed device performs its initial attach to the network as well as all the security setup. Additionally, in this phase the network is being informed either by the device and/or by other networking entities about the communication characteristics and service requirements of the device and decides the placement of the device in the group. In particular, a choice of group head or group member assignment can be performed based on which is more suitable for the communication characteristics and service requirements of the respective device. This information can be forwarded to the devices by the entity which is responsible for performing the grouping of the devices, i.e., the "Grouping Manager". The Grouping Manager can be responsible for the placement of the devices to the groups is a logically centralized entity and can have a greater view of the network, since in some embodiments it can aggregate information from several network elements. This logically centralized entity may be a totally new entity or collocate with an already available entity (e.g., mobility management entity in LTE/LTE-A networks).

The method 400 shown in FIG. 4 can be seen as an example initialization phase.

• A communication phase: in this phase the devices are transmitting to the group head their data and the group head aggregates the information from all the group members and proceeds in the joint transmission of the aggregated data to the network. During the communication phase, newly deployed devices can be integrated in the already established groups, or new groups can be formed by the grouping manager.

The initialization phase and the communication phase can be implemented as an iterative process starting from the devices with the shortest delay requirements and being repeated until no devices with periodic transmission are neither grouped nor group heads. A device with periodic transmissions that it is not associated to a group head becomes a group head and competes for random access channel resources. If no other devices are associated with a group head, then this device remains group head in the sense that it competes for random access channel resources. This process is illustrated in FIG. 6A and FIG. 6B.

FIG. 6A is a schematic illustration of the topology of a communication network 600, comprising a grouping manager 100, a base station 610, and five user equipments 620-628. The topology of FIG. 6A corresponds to the scenario before user equipments have been grouped. The devices 620-628 communicate with the network through a the base station 610. Additionally, the devices 620-628 communicate (through the base station 610) with the Grouping Manager 100 which is responsible for the grouping of the devices.

FIG. 6B is a schematic illustration of the communication network 600 of FIG. 6A, after a grouping of the user equipments 620-628 has been performed into a first group 630 and a second group 632.

As shown in FIG. 6B, once the grouping manager 100 decides the grouping, the devices 620-628 communicate with the network through the group representatives (in this exemplary implementation, the first device 620 is the group representative for the first group 630 and the fifth device 628 is the group representative for the second group 632), as decided by the Grouping Manager 100.

Once a newly deployed device performs its initial attach to the network, its sends to the Grouping Manager 100 a set of information fields which may include one or more of the following:

a service measurement, in particular at least one of the following: a service access periodicity, a data rate, a service type, a transmission delay requirement, a transmission delay tolerance and a time synchronization of data transmissions; and

a device description information, in particular at least one of the following: an available battery information, a maximum battery charging level, a device central processing unit description, a memory information, an operating system information, a screen size, a screen resolution, a power and/or energy information, a battery consumption rate, a battery level, a current CPU load level, a current memory load level, and an information about one or more protocols supported by the user equipment. In other alternative implementations the Grouping Manager may obtain part of the aforementioned information from other networking devices as well including servers, databases, etc. In one exemplary implementation in LTE/LTE-A networks the Grouping Manager could access service periodicity information through the Home Subscriber Server (HSS).

Once the Grouping Manager collects the aforementioned information it can proceed to the grouping of the devices based on the delay requirements and the predicted transmissions by considering transmission periodicity. Initially the devices are being classified to ones that have periodic transmissions and all the other devices. Only the devices with periodic transmissions may be grouped by the Grouping manager. All the other devices are not being grouped and compete individually for Random Access Channel resources.

After this initial phase, the Grouping Manager selects as group head the device with the shortest delay requirements and best radio measurements including but not limited to the average RSRP/RSRQ/RSS measurements. The reason that this device is selected as group head is that it has to transmit with certain hard delay requirements and it has to have priority when competing for RACH resources. Afterwards, devices with the same periodicity but relaxed delay requirements are being grouped with the appointed group head if their delay requirements are not being violated. The grouping of the devices to group heads can be done by considering several parameters including but not limiting to their location, their mobility (the group heads should have the same or similar relative distance throughout the grouping period) the available battery, the supported protocols, the device capabilities (e.g., battery consumption rate, battery level, current CPU, current memory). FIG. 7 is a flow chart of a method 700 for determining the group assignment.

In a first step 702, the devices are classified periodic or non-periodic. The non-periodic devices remain ungrouped. In a second step 704, the devices are classified with periodic transmission according to their periodicity.

In a third step 706, the devices are selected with the shortest delay requirement and the best average RSRP/RSRQ and marked as group heads. In a fourth step 708, depending on the density (in location and time) the group heads are associated and groups are formed. In a fifth step 710, the remaining devices with the same periodicity are associated to group heads, if their delay requirements can be covered with the transmission of the group head.

In a sixth step 712, it is decided whether there are still further un-clustered devices, i.e. devices that have not been assigned to a group yet. If so, the method continues in the third step 706. Otherwise, if there are no devices left to be grouped, the method continues with the seventh step 714, and waits for the attachment of new devices in the system.

FIG. 8 shows a schematic diagram 800 of several transmission requests. The horizontal axis 802 corresponds to the time and the vertical axis (not explicitly shown in FIG. 8) corresponds to a transmission urgency.

For example, a transmission window 810 for a transmission of device D starts at first time point 812 and ends at second time point 814. The first time point 812 corresponds to when the data is available for transmission, the second time point 814 corresponds to when the data needs to be transmitted at the latest. The duration of time between first time point 812 and second time point 814 is referred to as transmission delay tolerance duration 816.

FIG. 8 depicts an exemplary implementation on how the devices are being grouped considering only the service requirements, so as to highlight how the service requirements of each device are not being violated. Specifically the service requirements considered in this example are the transmission periodicity and the delay tolerance. In this particular example, all the devices is assumed to have the same periodicity of transmissions and the same average levels of radio transmissions. Additionally, it is assumed that these devices are static. In FIG. 8 the delay requirements for 5 devices are depicted; the higher the bar is, the shorter the delay tolerance of the service that the device accesses. The grouping manager initially sets as group head the device with the shorter delay requirements (in this example device A). Then it associates to it device E, since the delay requirements of device E may be covered by a joint transmission for the two devices - performed by device A. The other the devices may not be served by one joint transmission - since their delay requirements will be violated if they provide their data to device A and device A performs one joint transmission for all the devices.

Thus the Grouping Manager will select as group head the device with the shorter delay re- quirements that is not a group member. In this example the Grouping Manager will select as group head device C, which has the shortest delay requirements among devices B, C, and D. Then, since devices B and D can be served with a joint transmission without violating their delay requirements from device C, the Grouping Manager will group them with the device C. In the presented example it is assumed that all the devices are having the same average radio (e.g., RSRP, RSRQ, RSS, RSSI, etc.) measurements so as to highlight the impact of the service (i.e., periodicity, delay, etc.) requirements. In case of different radio measurements the devices with better radio link conditions could be prioritized. Similarly, in the presented example the devices are considered static. However, the same grouping could be achieved if the devices had the same or similar mobility, or mobility patterns.

In the special case, where two devices may have the same delay tolerance, the Grouping Manager selects as group head the device whose delay tolerance period ends first so as not to violate both devices delay requirements. In the exemplary implementation of FIG. 9, the Grouping Manager will allocate as group head the device A, but Device A has to be informed that it will have to wait before transmitting, so as to obtain the data from device B. This information may be obtained either by an update message by the Grouping Manager, or by dedicated messages from the device B during the attach process. When a new device is introduced in the network, it provides to the Grouping Manager its local measurements and information related to its service requirements, through its initial attach request. Then the Grouping Manager undertakes to incorporate it to the already available groups or to form a new group. In case the Grouping Manager needs additional information he may collects either directly (from the device) or indirectly (from any other networking device such as server, database, etc.). This is illustrated in more detail in FIG. 10, which presents an algorithm for the incorporation of a newly deployed device in an already established network with various groups. In a first step 1002, a new device is introduced in the system. This can occur, for example, when a new device comes into the reach of a base station.

In a second step 1004, it is determined, whether the new device is non-periodic (step 1004). This can be determined e.g. by looking up information about the device in a database, or by requesting periodicity information from the new device. The new device may also send periodicity information on its own initiative.

If the new device is non-periodic, it remains ungrouped (step 1006).

In step 1008 it is determined whether the same periodicity has been identified again. If not, the new device is selected in step 1010 as cluster head (i.e. group head).

Otherwise, if the same periodicity has been identified again, the devices with the shortest delay requirement and best average RSRP/RSRQ are selected and marked as group heads. In particular, this is performed among devices which have a same periodicity.

In case two devices have the same delay requirements the devices is selected so as to fulfil both devices delay requirements.

In a further step 1014, the remaining devices with the same periodicity are associated to group heads, if their delay requirements can be covered with the transmission of the group head.

FIG. 11 illustrates the message exchange in an exemplary implementation in an LTE/LTE-A network for the process of attachment of a newly deployed device in the network. In this exemplary implementation the Grouping Manager is a standalone entity that communicates with other networking entities directly or indirectly. As is shown, when the UE performs its initial attach to the network, it provides its information to the network. The local information includes but is not limited to the average values of radio information (e.g., RSS, RSSI, RSRP, RSRQ, etc.), device capabilities (e.g., processing capabilities, battery, battery consumption), location, mobility pattern, etc. This information is being transferred to the Mobility Management Entity (MME) through the eNB. The MME provides this information to the Grouping Manager and the latter requests information related to the service characteristics of the device that performs the attach request. This information includes but is not limited to service access periodicity, delay requirements, etc. This information may be provided by other networking devices as well (e.g., other registration servers, or the device that performs the attach request).

Subsequently, the Grouping Manager groups the device with the other devices in the vicinity and provides this information to the device (through the MME and the eNB) that performed the attach request. Specifically, the Grouping Manager provides to the device the group head ID. This information element is transferred through an enhanced Attach Accept message from the MME to the UE. From this point and onward the device will communicate its information to the network only through the group head. The group will provide in an aggregated manner to the network, the data and the ID of each device that belongs to the group.

In more detail, the steps of the method shown in FIG. 11 are as follows:

In a first step 1120, UE A 1102 and eNB 1106 perform an R C connection setup.

In step 1122, UE A 1102 sends a request which may include e.g. a Globally Unique ID (GUTI), a UE network capability, an avg. RSRQ per cell ID and/or a location to the MME 1108.

In step 1124, UE A 1102, Group Head 1104, eNB 1106 and MME 1108 perform Non- Access Stratum (NAS) Security Setup.

In step 1126, MME 1108 sends UE information which may include e.g. a Globally Unique Temporary ID (GUTI), a UE network capability, an avg. RSRQ per cell ID and/or a location to the Grouping Manager 1110.

In step 1128, the Grouping Manager 1110 and the HSS 1112 exchange UE information which may include a periodicity, a delay tolerance and/or a mobility status).

In step 1130, the Grouping Manager 1110 performs a grouping algorithm, also referred to as clustering algorithm. In step 1132, the Grouping Manager 1110 sends UE information which may include e.g. a Globally Unique Temporary ID (GUTI), a UE network capability, an avg. RSRQ per cell ID and/or a location to the MME 1108. In step 1134, the MME 1108 sends an attach accept message to the UE A 1102. The attach accept message includes a group head ID.

In step 1136, the UE A 1 102, the Group Head 1104, the eNB 1106 and the MME 1108 perform an NAS Security Setup.

In step 1138, the UE A sends an attach complete message (which includes cluster head information) to the MME 1108. Furthermore, transmission of data is performed.

FIG. 12 presents the communication phase of the proposed invention, through the group head. In particular, FIG. 12 shows an exchange of messages between a UE A 1202, a group head 1204 (also referred to as cluster head) and an eNB 1206.

In step 1220, the UE A 1202 sends a data transmission (including a GUTI and payload data) to the Group Head 1204.

In step 1224, the Group Head 1204 sends a RACH request to the eNB 1206.

In step 1226, the eNB 1206 sends a RACH response to the Group Head 1204. In step 1228, the Group Head 1204 and the eNB 1206 perform a RRC connection setup.

In step 1230, the Group Head 1204 sends a Joint Data transmission (including the GUTI and transmission Data) for all UEs in the group to the eNB 1206. For example, the group head may transmit all payload data that it has accumulated from a number of other group member devices.

The above-described mechanism can be extended to other concepts that require group handling (e.g., mobility management). In particular, the introduction of the Grouping Management unit being responsible to perform the device grouping according to acquired UE information gives the flexibility to use the grouping manager in scenarios where users may form groups and connect to heterogeneous networks consisting of Femto/Pico/Micro/Macro stations. Nevertheless, the grouping manager may be easily extended so as not to be affected at all from the stability of the group and thus, may be applied in any scenario (i.e., pedestrians, cars, trains, MTC, etc.).

As outlined above, embodiments of the present invention include a method of minimizing the number of devices competing for RACH resources by grouping the devices and performing group based random access channel requests. Some embodiments of the invention can improve the network access from network devices, by performing device grouping based on service, network, and location characteristics. Specifically, a signalling overhead of Random Access Channel can be improved, by exploiting common service, network, and location characteristics.

Embodiments of the invention comprise:

• Mechanisms for grouping the devices based on service, network, radio, location, and mobility characteristics

• Mechanisms for incorporating newly deployed devices in groups

• Mechanisms for joint transmissions by considering the service requirements of the most demanding services that the devices access. A method in accordance with the present invention may involve grouping devices by considering multiple criteria including for grouping including (but not limited to):

a. communication characteristics (e.g. delay requirements, periodicity of transmission, etc.), b. network measurements (e.g., RSRP, RSRQ, RSS, SINR, etc.)

c. location information, and

d. mobility patterns.

Embodiments may involve of incorporating devices in the system when new devices are being associated in the network. A method may also involve joint transmissions where only one device transmits the data of the group. A method may also involve updating a composition of groups when new devices attach to the network.

Some benefits expected from a LTE communication system which uses the grouping manager can include a reduction of a collision rate and a reduction of the number of collisions under various network conditions (e.g., ultra dense environment) when accessing the Random Access Channel. In the proposed method, the grouping process considers as potential group heads devices with stringent delay requirements, thus only these devices compete for random access whereas all the other devices are associated to these devices and may have increased delay (within their accepted delay requirements). Thus the only a limited number of devices competes for random access preambles. The benefits may be increased in high machine density environments.

Another benefit may be an increase of the spectral efficiency. Since the data for being transmitted are aggregated in the group heads, they are transmitting the data to the network in joint transmissions, thus reducing the signalling cost.

Finally, the proposed invention will benefit the overall delay since the devices access the network without requiring many Random Access Attempts. This enables the system access in shorter times.

The foregoing descriptions are only implementation manners of the present invention, the scope of the present invention is not limited to this. Any variations or replacements can be easily made through person skilled in the art. Therefore, the protection scope of the present invention should be subject to the protection scope of the attached claims.

Claims

A grouping manager (100, 1110) for a communication network (600), the grouping manager comprising:

a receiver (110) configured to receive device information about a plurality of devices (620-628) in the communication network,

a processor (120) configured to assign at least one of the plurality of devices as group head or group member based on the received device information, and a transmitter (130) configured to transmit a notification information about the group assignment,

wherein the device information comprise a transmission delay tolerance.

The grouping manager (100, 1110) of claim 1, wherein the processor (120) is configured to assign the plurality of devices (620-628) to a plurality of groups (630, 632) and to assign devices with overlapping delay tolerance periods to a same group.

The grouping manager (100, 1110) of one of the previous claims, wherein the processor (120) is configured to only assign mobile devices that are determined to have a periodic transmission.

The grouping manager (100, 1110) of one of the previous claims, wherein the processor (120) is configured to assign a device as group head (620, 628) if its transmission delay tolerance is lowest among the transmission delay tolerances of the plurality of devices (620-628).

The grouping manager (100, 1110) of claim 4, wherein the processor (120) is configured to, if two or more devices have a same minimum transmission delay tolerance, assign as group head a device with an earliest ending of a transmission delay tolerance period and/or assign as group head a device with a best signal quality measurement.

The grouping manager (100, 1110) of one of the previous claims, wherein the transmitter (130) is further configured to transmit a transmission-wait message that instructs a device (620, 628) that is assigned as group head to wait with transmission, wherein in particular the transmission- wait message comprises a wait interval indication.

The grouping manager (100, 1110) of one of the previous claims, wherein the grouping manager (100, 1110) further comprises a second receiver configured to receive at least a part of the device information from a node (1108, 1112) in the communication network (600) that is not a user equipment, in particular from a subscriber server, in particular a home subscriber server, HSS (1112).

The grouping manager (100, 1110) of one of the previous claims, wherein the device information further comprises at least one of the following:

a service measurement, in particular at least one of the following: a service access periodicity, a data rate, a service type, and a time synchronization of data transmissions; and

a device description information, in particular at least one of the following: an available battery information, a maximum battery charging level, a device central processing unit description, a memory information, an operating system information, a screen size, a screen resolution, a power and/or energy information, a battery consumption rate, a battery level, a current CPU load level, a current memory load level, and an information about one or more protocols supported by the user equipment.

The grouping manager (100, 1110) of one of the previous claims, wherein the transmitter (130) is configured to transmit the notification information as part of an attach accept message.

The grouping manager (100, 1110) of one of the previous claims, wherein the grouping manager is a standalone entity, a mobility server, in particular a mobility management entity, MME, or a base station of the communication network.

11. A user equipment (200) for a communication network, the user equipment comprising a transmitter (210) configured to transmit an accept request message that comprises a transmission delay tolerance and/or a periodicity information.

12. A user equipment (300) for a communication network, the user equipment comprising:

a first receiver (310) configured to receive a group head notification information, a second receiver (320) configured to receive group member transmit data from a group member device, and

a transmitter (330) configured to transmit the group member transmit data and local transmit data when the local transmit data is available.

13. A method (400) for determining a group head from a plurality of devices (620-628) in a communication network (600), the method comprising:

receiving (410) device information,

assigning (420) at least one of a plurality of devices (620-628) as group head or group member based on the received device information, and

transmitting (430) a notification information about the group assignment, wherein the device information comprise a transmission delay tolerance.

14. The method (400) of claim 13, wherein the method is carried out when a new device connects to a base station (1106, 1206) and/or when a group head disconnects from a base station (1106, 1206).

15. A method (500) for communicating in a wireless communication network (600), the method comprising:

receiving (510) a group head notification information,

receiving (520) group member transmit data from a group member device that is assigned as group member,

waiting (530) until a local transmit data is available for transmission, and transmitting (540) the group member transmit data and the local transmit data.