WO2024074078A1

WO2024074078A1 - Methods and apparatuses for enhanced csi-rs

Info

Publication number: WO2024074078A1
Application number: PCT/CN2023/111298
Authority: WO
Inventors: Yi Zhang; Chenxi Zhu; Wei Ling
Original assignee: Lenovo (Beijing) Limited
Priority date: 2023-08-04
Filing date: 2023-08-04
Publication date: 2024-04-11

Abstract

Various aspects of the present disclosure relate to methods and apparatuses for enhanced channel state information reference signal (CSI-RS). According to an embodiment of the present disclosure, a user equipment (UE) can include: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: receive an indication for indicating one or more CSI-RS resources; determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and receive CSI-RS on the determined physical resource.

Description

METHODS AND APPARATUSES FOR ENHANCED CSI-RS

TECHNICAL FIELD

The present disclosure relates to wireless communications, and more specifically to methods and apparatuses for enhanced channel state information reference signal (CSI-RS) .

BACKGROUND

A wireless communications system may include one or multiple network communication devices, such as base stations (BSs) , which may support wireless communications for one or multiple user communication devices, which may be otherwise known as user equipment (UE) , or other suitable terminology. The wireless communications system may support wireless communications with one or multiple user communication devices by utilizing resources of the wireless communication system (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers, or the like) . Additionally, the wireless communications system may support wireless communications across various radio access technologies including third generation (3G) radio access technology, fourth generation (4G) radio access technology, fifth generation (5G) radio access technology, among other suitable radio access technologies beyond 5G (e.g., sixth generation (6G) ) .

SUMMARY

An article "a" before an element is unrestricted and understood to refer to "at least one" of those elements or "one or more" of those elements. The terms "a, " "at least one, " "one or more, " and "at least one of one or more" may be interchangeable. As used herein, including in the claims, "or" as used in a list of items (e.g., a list of items prefaced by a phrase such as "at least one of" or "one or more of" or "one or both of" ) indicates an inclusive list such that, for example, a list of at least one of A, B, or C means A or B or C or AB or AC or BC or ABC (i.e., A and B and C) . Also, as used herein, the phrase "based on" shall not be construed as a reference to a closed set of conditions. For example, an example step that is described as "based on condition A" may be based on both a condition A and a condition B without departing from the scope of the present disclosure. In other words, as used herein, the phrase "based on" shall be construed in the same manner as the phrase "based at least in part on. " Further, as used herein, including in the claims, a "set" may include one or more elements.

Some implementations of the methods and apparatuses described herein may include a UE for wireless communication. The UE may include: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the UE to: receive an indication for indicating one or more CSI-RS resources; determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and receive CSI-RS on the determined physical resource.

In some implementations of the UE described herein, in the case of the aggregated CSI-RS resource with 48 ports, the one or more CSI-RS resources include two CSI-RS resources with 24 ports or three CSI-RS resources with 16 ports; in the case of the aggregated CSI-RS resource with 64 ports, the one or more CSI-RS resources include two CSI-RS resources with 32 ports or four CSI-RS resources with 16 ports; in the case of the aggregated CSI-RS resource with 72 ports, the one or more CSI-RS resources include: three CSI-RS resources with 24 ports; or one CSI-RS resource with 48 ports and one CSI-RS resource with 24 ports; in the case of the aggregated CSI-RS resource with 96 ports, the one or more CSI-RS resources include: three CSI-RS resources with 32 ports; or one CSI-RS resource with 64 ports and one CSI-RS resource with 32 ports; or in the case of the aggregated CSI-RS resource with 128 ports, the one or more CSI-RS resources include two CSI-RS resources with 64 ports or four CSI-RS resources with 32 ports.

In some implementations of the UE described herein, a configuration of (N₁, N₂) for an antenna array is supported by the UE with N₁ being a number of antenna ports per polarization direction in a horizontal direction and N₂ being a number of antenna ports per polarization direction in a vertical direction: in the case of the aggregated CSI-RS resource with 48 ports, the configuration of (N₁, N₂) includes (8, 3) , (12, 2) , or (24, 1) ; in the case of the aggregated CSI-RS resource with 64 ports, the configuration of (N₁, N₂) includes (8, 4) , (16, 2) , or (32, 1) ; in the case of the aggregated CSI-RS resource with 72 ports, the configuration of (N₁, N₂) includes (12, 3) or (18, 2) ; in the case of the aggregated CSI-RS resource with 96 ports, the configuration of (N₁, N₂) includes (16, 3) , (24, 2) or (48, 1) ; or in the case of the aggregated CSI-RS resource with 128 ports, the configuration of (N₁, N₂) includes (8, 8) , (16, 4) , (32, 2) or (64, 1) .

In some implementations of the UE described herein, the one or more CSI-RS resources are time-division multiplexed on a symbol level or a slot level.

In some implementations of the UE described herein, the indication indicates different starting symbols in one slot for the one or more CSI-RS resources and there is no overlapping symbol among the one or more CSI-RS resources.

In some implementations of the UE described herein, the indication indicates a same set of parameters for each of the one or more CSI-RS resources, wherein the same set of parameters includes at least one of: a first parameter indicating a frequency domain resource allocation; a second parameter indicating a number of ports; a third parameter indicating a code-division multiplexing (CDM) type; a fourth parameter indicating a CSI-RS frequency density of each CSI-RS port per physical resource block (PRB) ; a fifth parameter indicating a frequency band for CSI-RS; a sixth parameter indicating an assumed ratio of physical downlink shared channel (PDSCH) energy per resource element (EPRE) to non-zero-power (NZP) CSI-RS EPRE; a seventh parameter indicating an assumed ratio of NZP CSI-RS EPRE to synchronization signal block (SSB) EPRE; an eighth parameter indicating a scrambling identity (ID) of CSI-RS; a ninth parameter indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS; or a tenth parameter containing a reference to a transmission configuration indicator (TCI) state indicating quasi co-located (QCL) source reference signal (s) and QCL type (s) .

In some implementations of the UE described herein, the indication indicates same slot (s) or adjacent slots for CSI-RS resources.

In some implementations of the UE described herein, the indication indicates a same set of parameters for each of the one or more CSI-RS resources, wherein the same set of parameters includes at least one of: a first parameter indicating a frequency domain resource allocation; a second parameter indicating a number of ports; a third parameter indicating a CDM type; a fourth parameter indicating a CSI-RS frequency density of each CSI-RS port per PRB; a fifth parameter indicating a frequency band for CSI-RS; a sixth parameter indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE; a seventh parameter indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE; an eighth parameter indicating a scrambling ID of CSI-RS; a ninth parameter indicating a CSI-RS periodicity; or a tenth parameter containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

In some implementations of the UE described herein, the indication indicates a CDM type for the aggregated CSI-RS resource.

In some implementations of the UE described herein, the CDM type has a frequency domain orthogonal cover code (FD-OCC) length equal to 2 and a time division orthogonal cover code (TD-OCC) length equal to 8, a FD-OCC length equal to 4 and a TD-OCC length equal to 1, a FD-OCC length equal to 4 and a TD-OCC length equal to 2, or a FD-OCC length equal to 4 and a TD-OCC length equal to 4.

In some implementations of the UE described herein, a space between starting symbols of two CSI-RS resources is equal to a TD-OCC length for a CSI-RS resource of the two CSI-RS resources.

In some implementations of the UE described herein, the indication indicates a same set of parameters for each of the one or more CSI-RS resources, wherein the same set of parameters includes at least one of: a first parameter indicating a frequency domain resource allocation; a second parameter indicating a number of ports; a third parameter indicating a CSI-RS frequency density of each CSI-RS port per PRB; a fourth parameter indicating a frequency band for CSI-RS; a fifth parameter indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE; a sixth parameter indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE; a seventh parameter indicating a scrambling ID of CSI-RS; an eighth parameter indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS; or a ninth parameter containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

In some implementations of the UE described herein, the one or more CSI-RS resources are frequency-division multiplexed on a PRB level.

In some implementations of the UE described herein, the indication indicates a CSI-RS frequency density of each CSI-RS port per PRB equal to 1/N for each of the one or more CSI-RS resources or for the aggregated CSI-RS resource, wherein N is a number of the one or more CSI-RS resources.

In some implementations of the UE described herein, the indication indicates a same set of parameters for each of the one or more CSI-RS resources, wherein the same set of parameters includes at least one of: a first parameter indicating a number of ports; a second parameter indicating a CDM type; a third parameter indicating a CSI-RS frequency density of each CSI-RS port per PRB; a fourth parameter indicating a frequency band for CSI-RS; a fifth parameter indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE; a sixth parameter indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE; a seventh parameter indicating a scrambling ID of CSI-RS; an eighth parameter indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS; or a ninth parameter containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

In some implementations of the UE described herein, consecutive resource elements (REs) in a same symbol from a CSI-RS resource are used in a CDM group.

In some implementations of the UE described herein, the indication indicates a same set of parameters for each of the one or more CSI-RS resources, wherein the same set of parameters includes at least one of: a first parameter indicating a number of ports; a second parameter indicating a CSI-RS frequency density of each CSI-RS port per PRB; a third parameter indicating a frequency band for CSI-RS; a fourth parameter indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE; a fifth parameter indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE; a sixth parameter indicating a scrambling ID of CSI-RS; a seventh parameter indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS; or an eighth parameter containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

In some implementations of the UE described herein, at least two of the one or more CSI-RS resources are time-division multiplexed on a symbol level or a slot level and at least two of the one or more CSI-RS resources are frequency-division multiplexed on a PRB level.

In some implementations of the UE described herein, the indication indicates a same set of parameters for each of the one or more CSI-RS resources, wherein the same set of parameters includes at least one of: a first parameter indicating a number of ports; a second parameter indicating a CDM type; a third parameter indicating a CSI-RS frequency density of each CSI-RS port per PRB; a fourth parameter indicating a frequency band for CSI-RS; a fifth parameter indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE; a sixth parameter indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE; a seventh parameter indicating a scrambling ID of CSI-RS; an eighth parameter indicating a CSI-RS periodicity; or a ninth parameter containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

In some implementations of the UE described herein, the indication indicates one CSI-RS resource, and the indication further indicates repetitions of the one CSI-RS resource in multiple symbols, multiple slots, or multiple PRBs to determine the aggregated CSI-RS resource.

In some implementations of the UE described herein, the one or more CSI-RS resources are code-division multiplexed on a sequence level.

In some implementations of the UE described herein, the indication indicates a different scrambling ID for each CSI-RS resource of the one or more CSI-RS resources to generate a CSI-RS sequence for each CSI-RS resource.

In some implementations of the UE described herein, the indication indicates a same set of parameters for each of the one or more CSI-RS resources, wherein the same set of parameters includes at least one of: a first parameter indicating a frequency domain resource allocation; a second parameter indicating a number of ports; a third parameter indicating a first starting symbol for CSI-RS; a fourth parameter indicating a second starting symbol for CSI-RS; a fifth parameter indicating a CDM type; a sixth parameter indicating a CSI-RS frequency density of each CSI-RS port per PRB; a seventh parameter indicating a frequency band for CSI-RS;an eighth parameter indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE; a ninth parameter indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE; a tenth parameter indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS;or an eleventh parameter containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

In some implementations of the UE described herein, the at least one processor is configured to cause the UE to determine port indexes of the first number of ports first within the one or more CSI-RS resources, then within a CDM group, and last across CDM groups in the frequency domain and then in the time domain.

In some implementations of the UE described herein, the indication indicates at least one of the following multiplexing schemes for the one or more CSI-RS resources: time-division multiplexing, frequency-division multiplexing, or CDM.

Some implementations of the methods and apparatuses described herein may include a processor for wireless communication. The processor may include: at least one controller coupled with at least one memory and configured to cause the processor to: receive an indication for indicating one or more CSI-RS resources; determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and receive CSI-RS on the determined physical resource.

Some implementations of the methods and apparatuses described herein may include a BS for wireless communication. The BS may include: at least one memory; and at least one processor coupled with the at least one memory and configured to cause the BS to: transmit an indication for indicating one or more CSI-RS resources; determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and transmit CSI-RS on the determined physical resource.

Some implementations of the methods and apparatuses described herein may include a method performed by a UE. The method may include: receiving an indication for indicating one or more CSI-RS resources; determining a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and receiving CSI-RS on the determined physical resource.

Some implementations of the methods and apparatuses described herein may include a method performed by a BS. The method may include: transmitting an indication for indicating one or more CSI-RS resources; determining a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and transmitting CSI-RS on the determined physical resource.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the application can be obtained, a description of the application is rendered by reference to specific embodiments thereof, which are illustrated in the appended drawings. These drawings depict only example embodiments of the application and are not therefore to be considered limiting of its scope.

Figure 1 illustrates an example of a wireless communications system in accordance with aspects of the present disclosure.

Figure 2 illustrates a flowchart of an exemplary method performed by a UE in accordance with aspects of the present disclosure.

Figures 3-7 illustrate exemplary physical resources for an aggregated CSI-RS resource with 64 ports in accordance with aspects of the present disclosure.

Figure 8 illustrates a flowchart of an exemplary method performed by a BS in accordance with aspects of the present disclosure.

Figure 9 illustrates an example of a UE in accordance with aspects of the present disclosure.

Figure 10 illustrates an example of a processor in accordance with aspects of the present disclosure.

Figure 11 illustrates an example of a BS in accordance with aspects of the present disclosure.

DETAILED DESCRIPTION

The detailed description of the appended drawings is intended as a description of preferred embodiments of the present application and is not intended to represent the only form in which the present application may be practiced. It should be understood that the same or equivalent functions may be accomplished by different embodiments that are intended to be encompassed within the spirit and scope of the present application.

While operations are depicted in the drawings in a particular order, persons skilled in the art will readily recognize that such operations need not be performed in the particular order as shown or in a sequential order, or that all illustrated operations need be performed, to achieve desirable results; sometimes one or more operations can be skipped. Further, the drawings can schematically depict one or more example processes in the form of a flow diagram. However, other operations that are not depicted can be incorporated in the example processes that are schematically illustrated. For example, one or more additional operations can be performed before, after, simultaneously, or between any of the illustrated operations. In certain circumstances, multitasking and parallel processing can be advantageous.

Reference will now be made in detail to some embodiments of the present application, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as 3rd generation partnership project (3GPP) long-term evolution (LTE) and LTE advanced, 3GPP 5G new radio (NR) , 5G-Advanced, 6G, and so on. It is contemplated that along with developments of network architectures and new service scenarios, all embodiments in the present application are also applicable to similar technical problems; and moreover, the terminologies recited in the present application may change, which should not affect the principle of the present application.

Aspects of the present disclosure are described in the context of a wireless communications system.

Figure 1 illustrates an example of a wireless communications system 100 in accordance with aspects of the present disclosure. The wireless communications system 100 may include one or more network equipments (NEs) (e.g., BSs) 102, one or more UEs 104, and a core network (CN) 106. The wireless communications system 100 may support various radio access technologies. In some implementations, the wireless communications system 100 may be a 4G network, such as an LTE network or an LTE-Advanced (LTE-A) network. In some other implementations, the wireless communications system 100 may be a NR network, such as a 5G network, a 5G-Advanced (5G-A) network, or a 5G ultrawideband (5G-UWB) network. In other implementations, the wireless communications system 100 may be a combination of a 4G network and a 5G network, or other suitable radio access technology including Institute of Electrical and Electronics Engineers (IEEE) 802.11 (Wi-Fi) , IEEE 802.16 (WiMAX) , IEEE 802.20. The wireless communications system 100 may support radio access technologies beyond 5G, for example, 6G. Additionally, the wireless communications system 100 may support technologies, such as time division multiple access (TDMA) , frequency division multiple access (FDMA) , or code division multiple access (CDMA) , etc.

The one or more NEs 102 may be dispersed throughout a geographic region to form the wireless communications system 100. One or more of the NEs 102 described herein may be or include or may be referred to as a network node, a base station, a network element, a network function, a network entity, a radio access network (RAN) , a NodeB, an eNodeB (eNB) , a next-generation NodeB (gNB) , or other suitable terminology. An NE 102 and a UE 104 may communicate via a communication link, which may be a wireless or wired connection. For example, an NE 102 and a UE 104 may perform wireless communication (e.g., receive signaling, transmit signaling) over a Uu interface.

An NE 102 may provide a geographic coverage area for which the NE 102 may support services for one or more UEs 104 within the geographic coverage area. For example, an NE 102 and a UE 104 may support wireless communication of signals related to services (e.g., voice, video, packet data, messaging, broadcast, etc. ) according to one or multiple radio access technologies. In some implementations, an NE 102 may be moveable, for example, a satellite associated with a non-terrestrial network (NTN) . In some implementations, different geographic coverage areas associated with the same or different radio access technologies may overlap, but the different geographic coverage areas may be associated with different NEs 102.

The one or more UEs 104 may be dispersed throughout a geographic region of the wireless communications system 100. A UE 104 may include or may be referred to as a remote unit, a mobile device, a wireless device, a remote device, a subscriber device, a transmitter device, a receiver device, or some other suitable terminology. In some implementations, the UE 104 may be referred to as a unit, a station, a terminal, or a client, among other examples. Additionally, or alternatively, the UE 104 may be referred to as an Internet-of-Things (IoT) device, an Internet-of-Everything (IoE) device, or machine-type communication (MTC) device, among other examples.

A UE 104 may be able to support wireless communication directly with other UEs 104 over a communication link. For example, a UE 104 may support wireless communication directly with another UE 104 over a device-to-device (D2D) communication link. In some implementations, such as vehicle-to-vehicle (V2V) deployments, vehicle-to-everything (V2X) deployments, or cellular-V2X deployments, the communication link may be referred to as a sidelink. For example, a UE 104 may support wireless communication directly with another UE 104 over a PC5 interface.

An NE 102 may support communications with the CN 106, or with another NE 102, or both. For example, an NE 102 may interface with other NE 102 or the CN 106 through one or more backhaul links (e.g., S1, N2, N2, or network interface) . In some implementations, the NEs 102 may communicate with each other directly. In some other implementations, the NEs 102 may communicate with each other indirectly (e.g., via the CN 106. In some implementations, one or more NEs 102 may include subcomponents, such as an access network entity, which may be an example of an access node controller (ANC) . An ANC may communicate with the one or more UEs 104 through one or more other access network transmission entities, which may be referred to as radio heads, smart radio heads, or transmission-reception points (TRPs) .

The CN 106 may support user authentication, access authorization, tracking, connectivity, and other access, routing, or mobility functions. The CN 106 may be an evolved packet core (EPC) , or a 5G core (5GC) , which may include a control plane entity that manages access and mobility (e.g., a mobility management entity (MME) , an access and mobility management function (AMF) ) and a user plane entity that routes packets or interconnects to external networks (e.g., a serving gateway (S-GW) , a Packet Data Network (PDN) gateway (P-GW) , or a user plane function (UPF) ) . In some implementations, the control plane entity may manage non-access stratum (NAS) functions, such as mobility, authentication, and bearer management (e.g., data bearers, signal bearers, etc. ) for the one or more UEs 104 served by the one or more NEs 102 associated with the CN 106.

The CN 106 may communicate with a packet data network over one or more backhaul links (e.g., via an S1, N2, N2, or another network interface) . The packet data network may include an application server. In some implementations, one or more UEs 104 may communicate with the application server. A UE 104 may establish a session (e.g., a protocol data unit (PDU) session, or the like) with the CN 106 via an NE 102. The CN 106 may route traffic (e.g., control information, data, and the like) between the UE 104 and the application server using the established session (e.g., the established PDU session) . The PDU session may be an example of a logical connection between the UE 104 and the CN 106 (e.g., one or more network functions of the CN 106) .

In the wireless communications system 100, the NEs 102 and the UEs 104 may use resources of the wireless communications system 100 (e.g., time resources (e.g., symbols, slots, subframes, frames, or the like) or frequency resources (e.g., subcarriers, carriers) ) to perform various operations (e.g., wireless communications) . In some implementations, the NEs 102 and the UEs 104 may support different resource structures. For example, the NEs 102 and the UEs 104 may support different frame structures. In some implementations, such as in 4G, the NEs 102 and the UEs 104 may support a single frame structure. In some other implementations, such as in 5G and among other suitable radio access technologies, the NEs 102 and the UEs 104 may support various frame structures (e.g., multiple frame structures) . The NEs 102 and the UEs 104 may support various frame structures based on one or more numerologies.

One or more numerologies may be supported in the wireless communications system 100, and a numerology may include a subcarrier spacing and a cyclic prefix. A first numerology (e.g., μ=0) may be associated with a first subcarrier spacing (e.g., 15 kHz) and a normal cyclic prefix. In some implementations, the first numerology (e.g., μ=0) associated with the first subcarrier spacing (e.g., 15 kHz) may utilize one slot per subframe. A second numerology (e.g., μ=1) may be associated with a second subcarrier spacing (e.g., 30 kHz) and a normal cyclic prefix. A third numerology (e.g., μ=2) may be associated with a third subcarrier spacing (e.g., 60 kHz) and a normal cyclic prefix or an extended cyclic prefix. A fourth numerology (e.g., μ=3) may be associated with a fourth subcarrier spacing (e.g., 120 kHz) and a normal cyclic prefix. A fifth numerology (e.g., μ=4) may be associated with a fifth subcarrier spacing (e.g., 240 kHz) and a normal cyclic prefix.

A time interval of a resource (e.g., a communication resource) may be organized according to frames (also referred to as radio frames) . Each frame may have a duration, for example, a 10 millisecond (ms) duration. In some implementations, each frame may include multiple subframes. For example, each frame may include 10 subframes, and each subframe may have a duration, for example, a 1 ms duration. In some implementations, each frame may have the same duration. In some implementations, each subframe of a frame may have the same duration.

Additionally or alternatively, a time interval of a resource (e.g., a communication resource) may be organized according to slots. For example, a subframe may include a number (e.g., quantity) of slots. The number of slots in each subframe may also depend on the one or more numerologies supported in the wireless communications system 100. For instance, the first, second, third, fourth, and fifth numerologies (e.g., μ=0, μ=1, μ=2, μ=3, μ=4) associated with respective subcarrier spacings of 15 kHz, 30 kHz, 60 kHz, 120 kHz, and 240 kHz may utilize a single slot per subframe, two slots per subframe, four slots per subframe, eight slots per subframe, and 16 slots per subframe, respectively. Each slot may include a number (e.g., quantity) of symbols (e.g., orthogonal frequency division multiplexing (OFDM) symbols) . In some implementations, the number (e.g., quantity) of slots for a subframe may depend on a numerology. For a normal cyclic prefix, a slot may include 14 symbols. For an extended cyclic prefix (e.g., applicable for 60 kHz subcarrier spacing) , a slot may include 12 symbols. The relationship between the number of symbols per slot, the number of slots per subframe, and the number of slots per frame for a normal cyclic prefix and an extended cyclic prefix may depend on a numerology. It should be understood that reference to a first numerology (e.g., μ=0) associated with a first subcarrier spacing (e.g., 15 kHz) may be used interchangeably between subframes and slots.

In the wireless communications system 100, an electromagnetic (EM) spectrum may be split, based on frequency or wavelength, into various classes, frequency bands, frequency channels, etc. By way of example, the wireless communications system 100 may support one or multiple operating frequency bands, such as frequency range designations FR1 (410 MHz –7.125 GHz) , FR2 (24.25 GHz –52.6 GHz) , FR3 (7.125 GHz –24.25 GHz) , FR4 (52.6 GHz –114.25 GHz) , FR4a or FR4-1 (52.6 GHz –71 GHz) , and FR5 (114.25 GHz –300 GHz) . In some implementations, the NEs 102 and the UEs 104 may perform wireless communications over one or more of the operating frequency bands. In some implementations, FR1 may be used by the NEs 102 and the UEs 104, among other equipment or devices for cellular communications traffic (e.g., control information, data) . In some implementations, FR2 may be used by the NEs 102 and the UEs 104, among other equipment or devices for short-range, high data rate capabilities.

FR1 may be associated with one or multiple numerologies (e.g., at least three numerologies) . For example, FR1 may be associated with a first numerology (e.g., μ=0) , which includes 15 kHz subcarrier spacing; a second numerology (e.g., μ=1) , which includes 30 kHz subcarrier spacing; and a third numerology (e.g., μ=2) , which includes 60 kHz subcarrier spacing. FR2 may be associated with one or multiple numerologies (e.g., at least 2 numerologies) . For example, FR2 may be associated with a third numerology (e.g., μ=2) , which includes 60 kHz subcarrier spacing; and a fourth numerology (e.g., μ=3) , which includes 120 kHz subcarrier spacing.

With the development of communication technology, enhancements on downlink multiple input multiple output (MIMO) that facilitate the use of large antenna array, for both FR1 and FR2, are proposed to fulfil the demand for evolution of NR deployments, especially for 7GHz frequency band (s) . In existing 5G system, the CSI-RS port is designed based on a maximum port number of 32. However, for the large antenna array, a larger number of CSI-RS ports (e.g., more than 32 ports) may be used to further increase beamforming gain, thereby improving the cell coverage and cell average/edge throughput, especially for the case that the CSI-RS ports are implemented with full digital ports. Given this, the detail schemes for designing CSI-RS with more than 32 ports need to be addressed.

Embodiments of the present disclosure provide solutions for designing enhanced CSI-RS (or CSI-RS resource) with more than 32 ports. Specifically, one or multiple CSI-RS resources (e.g., legacy CSI-RS resources with no more than 32 ports) may be aggregated to generate a CSI-RS resource with more than 32 ports. For example, the solutions provide aggregation schemes, available resources, CDM schemes, etc. for the multiple CSI-RS resources or one CSI-RS resource with multiple repetitions to generate the CSI-RS resource with more than 32 ports. More details will be described in the following text in combination with the appended drawings.

Figure 2 illustrates a flowchart of an exemplary method in accordance with aspects of the present disclosure. The operations of the method illustrated in Figure 2 may be performed by a UE (e.g., UE 104 in Figure 1) as described herein or other apparatus with the like functions. In some implementations, the UE may execute a set of instructions to control functional elements of the UE to perform the described operations or functions.

As shown in Figure 2, in step 202, the UE may receive an indication for indicating one or more CSI-RS resources. For example, the indication may be an RRC signaling. In some cases, the one or more CSI-RS resources may be included in a group.

The one or more CSI-RS resources may be used to generate (e.g., aggregate) an aggregated CSI-RS resource. Accordingly, the one or more CSI-RS resources may be referred to as one or more component CSI-RS resources. In some examples, each of the one or more component CS-RS resources may have no more than 32 ports (also referred to as CSI-RS ports or CSI-RS antenna ports) . In some other examples, at least one of the one or more component CSI-RS resources may have more than 32 ports.

In step 204, the UE may determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more component CSI-RS resources, wherein the first number is more than 32. The physical resource may include at least one of time-domain resources or frequency-domain resources. Alternative or additionally, the UE may determine a sequence for the aggregated CSI-RS resource with the first number of ports based on the one or more component CSI-RS resources.

In step 206, the UE may receive CSI-RS on the determined physical resource.

According to some embodiments of the present disclosure, the number of ports for each of the one or more component CSI-RS resources is the same (hereinafter referred to as scheme 1) .

As an example, in the case of the aggregated CSI-RS resource with 48 ports, the one or more component CSI-RS resources may include two component CSI-RS resources with 24 ports or three component CSI-RS resources with 16 ports.

As another example, in the case of the aggregated CSI-RS resource with 64 ports, the one or more component CSI-RS resources may include two component CSI-RS resources with 32 ports or four component CSI-RS resources with 16 ports.

As yet another example, in the case of the aggregated CSI-RS resource with 72 ports, the one or more component CSI-RS resources may include three component CSI-RS resources with 24 ports.

As yet another example, in the case of the aggregated CSI-RS resource with 96 ports, the one or more component CSI-RS resources may include three component CSI-RS resources with 32 ports.

As yet another example, in the case of the aggregated CSI-RS resource with 128 ports, the one or more component CSI-RS resources may include two component CSI-RS resources with 64 ports or four component CSI-RS resources with 32 ports.

According to some other embodiments of the present disclosure, the numbers of ports for the one or more component CSI-RS resources may be different (hereinafter referred to as scheme 2) .

As an example, in the case of the aggregated CSI-RS resource with 72 ports, the one or more component CSI-RS resources may include one component CSI-RS resource with 48 ports and one component CSI-RS resource with 24 ports.

As another example, in the case of the aggregated CSI-RS resource with 96 ports, the one or more component CSI-RS resources may include one component CSI-RS resource with 64 ports and one component CSI-RS resource with 32 ports.

The indication received in step 202 may indicate the one or more component CSI-RS resources in various manners.

As an example, the indication may be an RRC signaling for the aggregated CSI-RS resource with more than 32 ports. The RRC signaling may include an ID for the aggregated CSI-RS resource and the ID (s) for the one or more component CSI-RS resources for generating the aggregated CSI-RS resource.

The following example illustrates a newly defined information element (IE) , e.g., NZP-CSI-RS-r19, in an RRC signaling (e.g., NZP-CSI-RS-ResourceSet as specified in 3GPP standard documents) for the aggregated CSI-RS resource with more than 32 ports.

The IE NZP-CSI-RS-r19 includes an ID for the aggregated CSI-RS resource with more than 32 ports (e.g., denoted as nzp-CSI-RS-ResourceId-r19) and IDs for the component CSI-RS resources (e.g., denoted as nzp-CSI-RS-ResourceId1, nzp-CSI-RS-ResourceId2, nzp-CSI-RS-ResourceId3, and nzp-CSI-RS-ResourceId4) for generating the aggregated CSI-RS resource with more than 32 ports. In such example, the aggregated CSI-RS resource may be generated by at least two component CSI-RS resources and at most four component CSI-RS resources.

As another example, the indication may be an RRC signaling, which includes a respective IE (e.g., "NZP-CSI-RS-Resource" ) for each component CSI-RS resource. The IE may include an item (e.g., named as "CSI-RS-LinkingId" ) which has the same value as an ID of the aggregated CSI-RS resource (e.g., denoted as nzp-CSI-RS-ResourceId-r19) , indicating that the corresponding component CSI-RS resource is used to generate the aggregated CSI-RS resource with more than 32 ports.

As another example, in the case of two component CSI-RS resources, the indication may be an RRC signaling indicating a resource pair, wherein the resource pair includes the two component CSI-RS resources.

For an antenna array, a configuration of (N₁, N₂) may be supported by the UE, wherein N₁ is a number of antenna ports per polarization direction in a horizontal direction (e.g., in a row) , and N₂ is a number of antenna ports per polarization direction in a vertical direction (e.g., in a column) .

As an example, for CSI-RS resource with no more than 32 ports, exemplary configurations of (N₁, N₂) based on Type 1 codebook design are shown in Table 1, which is a part of Table 5.2.2.2.1-2 as specified in TS 38.214.

Table 1: Supported configurations of (N₁, N₂)

As an example, for CSI-RS resource with more than 32 ports, exemplary configurations of (N₁, N₂) are shown in Table 2.

Table 2: Supported configurations of (N₁, N₂)

In the examples shown in Table 2, in the case of the aggregated CSI-RS resource with 48 ports, the configuration of (N₁, N₂) includes (8, 3) , (12, 2) , or (24, 1) ; in the case of the aggregated CSI-RS resource with 64 ports, the configuration of (N₁, N₂) includes (8, 4) , (16, 2) , or (32, 1) ; in the case of the aggregated CSI-RS resource with 72 ports, the configuration of (N₁, N₂) includes (12, 3) or (18, 2) ; in the case of the aggregated CSI-RS resource with 96 ports, the configuration of (N₁, N₂) includes (16, 3) , (24, 2) or (48, 1) ; or in the case of the aggregated CSI-RS resource with 128 ports, the configuration of (N₁, N₂) includes (8, 8) , (16, 4) , (32, 2) or (64, 1) .

In Table 2, for the antenna array with one row (i.e., N₂ = 1) , it may be introduced on account of a large horizontal precoding gain in the case that a large antenna size is needed. For example, it may be introduced for 7GHz frequency band (s) .

In some examples, when the configurations for an antenna array shown in Table 2 are supported, the aforementioned scheme 1 is enough to generate the aggregated CSI-RS resource. In other words, the aforementioned scheme 2 may not be used to generate the aggregated CSI-RS resource on account of the complexity for configuration.

As an example, in the case of the aggregated CSI-RS resource with 48 ports, the one or more component CSI-RS resources may include two component CSI-RS resources with 24 ports (alt. 1) or three component CSI-RS resources with 16 ports (alt. 2) . Both alt. 1 and alt. 2 are workable, but alt. 1 is simpler for configuration on account of small number of component CSI-RS resources for generating the aggregated CSI-RS resource while alt. 2 is more flexible for resource allocation on account of smaller number of time-frequency resources used for each component CSI-RS resource for generating the aggregated CSI-RS resource.

In some examples, the one or more component CSI-RS resources for generating the aggregated CSI-RS resource may take simplicity into consideration. In some examples, the one or more component CSI-RS resources may be based on the legacy CSI-RS resources with no more than 32 ports. In this way, it may be easy to define UE's capability based on whether to support more than 32 ports for the component CSI-RS resource.

The following embodiments provide solutions regarding how to aggregate the one or more component CSI-RS resources to generate the aggregated CSI-RS resource. Based on the aggregation scheme, the UE may determine the physical resource for the aggregated CSI-RS resource based on the one or more component CSI-RS resources.

Embodiment 1

Embodiment 1 provides solutions for aggregating the one or more component CSI-RS resources in the time domain (referred to as a time-division multiplexing (TDM) scheme) , which may be divided into Embodiment 1-1, Embodiment 1-2, and Embodiment 1-3.

Embodiment 1-1

In Embodiment 1-1, the one or more component CSI-RS resources are time-division multiplexed on a symbol level (which is referred to as a symbol level TDM scheme) .

For the symbol level TDM scheme, there is no overlapping symbol among the one or more component CSI-RS resources. Thus, the indication for indicating the one or more component CSI-RS resources may indicate different starting symbols in one slot for the one or more component CSI-RS resources. The starting symbol for a component CSI-RS resource may include a first starting symbol (e.g., indicated by firstOFDMSymbolInTimeDomain as specified in 3GPP standard documents) and/or a second starting symbol (e.g., indicated by firstOFDMSymbolInTimeDomain2 as specified in 3GPP standard documents) . For example, for different component CSI-RS resources, the indication (e.g., RRC signaling) may indicate (e.g., configure) different values for firstOFDMSymbolInTimeDomain and firstOFDMSymbolInTimeDomain2.

Based on the starting symbols in one slot as well as other configurations for the one or more component CSI-RS resources, the UE may determine the time-frequency resources for the one or more component CSI-RS resources based on the tables and formulas specified in, e.g., section 7.4.1.5.3 in TS 38.211, thereby determining the physical resource for the aggregated CSI-RS resource with more than 32 ports, which includes the time-frequency resources for the one or more component CSI-RS resources.

Figure 3 illustrates an exemplary physical resource for an aggregated CSI-RS resource with 64 ports in accordance with aspects of the present disclosure. The example in Figure 3 illustrates one slot (e.g., including 14 OFDM symbols denoted as symbol #0 to symbol #13) in the time domain and one PRB (e.g., including 12 subcarriers denoted as subcarrier #0 to subcarrier #11) in the frequency domain. A resource element (RE) may span one symbol in the time domain and one subcarrier in the frequency domain. The first two symbols in the slot may be used for physical downlink control channel (PDCCH) transmission, and the third symbol in the slot may be used for demodulation reference signal (DMRS) transmission.

In the example of Figure 3, two component CSI-RS resources with 32 ports (e.g., denoted as CSI-RS resource 1 and CSI-RS resource 2) may be indicated. The two component CSI-RS resources are time-division multiplexed on a symbol level to generate the aggregated CSI-RS resource with 64 ports.

In the example of Figure 3, the CDM type configured for each of the two component CSI-RS resources is "fd-CDM2" as specified in 3GPP standard documents. For "fd-CDM2, " a CDM group includes two REs consecutive in the frequency domain. Accordingly, each component CSI-RS resource may include 16 CDM groups.

The first starting symbol and the second starting symbol for CSI-RS resource 1 are symbol #6 and symbol #12 in the slot, respectively. Based on the CDM type, the port number, and the first starting symbol and the second starting symbol of CSI-RS resource 1, the UE may determine the time-domain resources of CSI-RS resource 1 include symbols #6, #7, #12 and #13 according to Table 7.4.1.5.3-1 and the formulas specified in section 7.4.1.5.3 in TS 38.211.

The first starting symbol and the second starting symbol for CSI-RS resource 2 are symbol #3 and symbol #9 in the slot, respectively. Based on the CDM type, the port number, and the first starting symbol and the second starting symbol of CSI-RS resource 2, the UE may determine the time-domain resources of CSI-RS resource 2 include symbols #3, #4, #9 and #10 according to Table 7.4.1.5.3-1 and the formulas specified in section 7.4.1.5.3 in TS 38.211.

Consequently, the UE may determine the physical resource for the aggregated CSI-RS resource, which includes the time-domain resources of CSI-RS resource 1 and CSI-RS resource 2.

In some cases, the frequency domain allocations for CSI-RS resource 1 and CSI-RS resource 2 may be indicated. Based on the CDM type, the port number, and the frequency domain allocations, the UE may determine the frequency-domain resources of CSI-RS resource 1 and CSI-RS resource 2 according to Table 7.4.1.5.3-1 and the formulas specified in section 7.4.1.5.3 in TS 38.211. Consequently, the UE may determine the physical resource for the aggregated CSI-RS resource, which includes the frequency-domain resources of CSI-RS resource 1 and CSI-RS resource 2.

In some cases of Embodiment 1-1, the one or more component CSI-RS resources may share a same set of parameters, which may include at least one of:

· a first parameter (e.g., frequencyDomainAllocation as specified in 3GPP standard documents) indicating a frequency domain resource allocation;

· a second parameter (e.g., nrofPorts as specified in 3GPP standard documents) indicating a number of ports;

· a third parameter (e.g., cdm-Type as specified in 3GPP standard documents) indicating a CDM type;

· a fourth parameter (e.g., density as specified in 3GPP standard documents) indicating a CSI-RS frequency density of each CSI-RS port per PRB;

· a fifth parameter (e.g., freqBand as specified in 3GPP standard documents) indicating a frequency band for CSI-RS;

· a sixth parameter (e.g., powerControlOffset as specified in 3GPP standard documents) indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE;

· a seventh parameter (e.g., powerControlOffsetSS as specified in 3GPP standard documents) indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE;

· an eighth parameter (e.g., scramblingID as specified in 3GPP standard documents) indicating a scrambling ID of CSI-RS;

· a ninth parameter (e.g., periodicityAndOffset as specified in 3GPP standard documents) indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS; or

· a tenth parameter (e.g., qcl-InfoPeriodicCSI-RS as specified in 3GPP standard documents) containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

Embodiment 1-2

In Embodiment 1-2, the one or more component CSI-RS resources are time-division multiplexed on a slot level (which is referred to as a slot level TDM scheme) . The slot level TDM scheme may be beneficial when, e.g., there are additional DMRS and/or sounding reference signal (SRS) in a slot and thus available symbols in the slot may be not enough for a CSI-RS resource with more than 32 ports.

For the slot level TDM scheme, to obtain similar estimated channel information and interference situation for all the CSI-RS ports, the indication for indicating the one or more component CSI-RS resources may indicate same slot (s) or adjacent slots for the component CSI-RS resources which are used for generating the aggregated CSI-RS resource with more than 32 ports. For example, the indication may indicate two adjacent slots for two component CSI-RS resources used for generating the aggregated CSI-RS resource, wherein each component CSI-RS resource is configured in one slot.

Figure 4 illustrates another exemplary physical resource for an aggregated CSI-RS resource with 64 ports in accordance with aspects of the present disclosure.

In the example of Figure 4, two component CSI-RS resources with 32 ports (e.g., denoted as CSI-RS resource 1 and CSI-RS resource 2) may be indicated. The two component CSI-RS resources are time-division multiplexed on a slot level to generate the aggregated CSI-RS resource with 64 ports.

The two component CSI-RS resources may be configured in two adjacent slots (e.g., slot n and slot n+1) . For example, CSI-RS resource 1 is configured in slot n and CSI-RS resource 2 is configured in slot n+1. In other words, the slot offset (e.g., indicated by periodicityAndOffset as specified in 3GPP standard documents) for CSI-RS resource 2 may be equal to the slot offset for CSI-RS resource 1 plus 1. The periodicity (e.g., indicated by periodicityAndOffset as specified in 3GPP standard documents) for CSI-RS resource 1 and the periodicity for CSI-RS resource 2 may be the same.

In the example of Figure 4, the first starting symbol and the second starting symbol for CSI-RS resource 1 and CSI-RS resource 2 are the same, i.e., which are symbol #6 and symbol #12 in a slot, respectively. Based on the CDM type, the port number, and the first starting symbol and the second starting symbol of CSI-RS resource 1 and CSI-RS resource 2, the UE may determine that the time-domain resources of CSI-RS resource 1 include symbols #6, #7, #12 and #13 in slot n and determine that the time-domain resources of CSI-RS resource 2 include symbols #6, #7, #12 and #13 in slot n+1 according to Table 7.4.1.5.3-1 and the formulas specified in section 7.4.1.5.3 in TS 38.211. Although in the example of Figure 4, the locations of symbols in a slot for CSI-RS resource 1 and CSI-RS resource 2 are the same, it is contemplated that the locations of symbols in a slot for CSI-RS resource 1 and CSI-RS resource 2 may be different, which should not affect the principle of the present disclosure.

In the example of Figure 4, the frequency-domain resources of CSI-RS resource 1 in slot n are the same as those of CSI-RS resource 1 in Figure 3, and the frequency-domain resources of CSI-RS resource 2 in slot n+1 are the same as those of CSI-RS resource 2 in Figure 3.

Consequently, the UE may determine the physical resource for the aggregated CSI-RS resource with 64 ports based on CSI-RS resource 1 and CSI-RS resource 2, which includes the time-domain resources and the frequency-domain resources of CSI-RS resource 1 and CSI-RS resource 2.

In some cases of Embodiment 1-2, the one or more component CSI-RS resources may share a same set of parameters, which may include at least one of:

· a ninth parameter (e.g., periodicityAndOffset as specified in 3GPP standard documents) indicating a CSI-RS periodicity; or

Embodiment 1-3

In Embodiment 1-3, a high dimension CDM, such as TD8 (i.e., TD-OCC length equal to 8) , may be introduced for the aggregated CSI-RS resource (which is referred to as TDM scheme with high dimension TD-OCC) . The high dimension CDM may increase a total transmit power from CDM-ed CSI-RS ports and improve channel estimation performance by achieving a spreading gain.

In some cases of Embodiment 1-3, the indication for indicating the component CSI-RS resources may indicate a CDM type for the aggregated CSI-RS resource. In some cases of Embodiment 1-3, the CDM type for the aggregated CSI-RS resource may be predefined.

In some cases, the CDM type for the aggregated CSI-RS resource may have a TD-OCC length equal to 8. For example, the CDM type may have a FD-OCC length equal to 2 and a TD-OCC length equal to 8, which may be defined as "cdm16-FD2-TD8. "

For "cdm16-FD2-TD8, " exemplary OCC sequences (i.e., w_f (k′) and w_t (l′) ) are shown in Table 3, wherein k' and l' may have the same definitions as those in TS 38.211. For example, k′ defines the index (es) of RE (s) in the frequency domain in a CDM group, and l′ defines the index (es) of RE (s) in the time domain in a CDM group. As shown in Table 3, k'=0, 1, and l'= 0, 1, 2, 3, 4, 5, 6, 7. The OCC sequences are used in the formulas as specified in section 7.4.1.5.2 in TS 38.211 to map the sequence of CSI-RS to the physical resources.

Table 3: OCC sequences w_f (k′) and w_t (l′) for cdm16-FD2-TD8

In some cases of Embodiment 1-3, the indication for indicating the component CSI-RS resources may also indicate a CDM type for each component CSI-RS resource. In some other cases of Embodiment 1-3, the indication may not indicate a CDM type for each component CSI-RS resource, and the UE may derive the CDM type for each component CSI-RS resource from the CDM type for the aggregated CSI-RS resource.

To achieve the spreading gain, channels for multiple REs with OCC are assumed the same. Given this, adjacent REs from different component CSI-RS resources can be used in one CDM group for the aggregated CSI-RS resource. For example, OFDM symbols from different component CSI-RS resources may be used for TD-OCC for the aggregated CSI-RS resource. To achieve this, a space between starting symbols of two component CSI-RS resources is equal to a TD-OCC length for a component CSI-RS resource of the two component CSI-RS resources.

Figure 5 illustrates yet another exemplary physical resource for an aggregated CSI-RS resource with 64 ports in accordance with aspects of the present disclosure.

In the example of Figure 5, the CDM type for the aggregated CSI-RS resource with 64 ports is "cdm16-FD2-TD8" . Two component CSI-RS resources with 32 ports (e.g., denoted as CSI-RS resource 1 and CSI-RS resource 2) are indicated. The TD-OCC length for CSI-RS resource 1 and CSI-RS resource 2 is 4.

To form a CDM group including adjacent REs from different component CSI-RS resources, the space between the starting symbol (e.g., denoted as starting symbol #1) for CSI-RS resource 1 and the starting symbol (e.g., denoted as starting symbol #2) for CSI-RS resource 2 is 4. In the example of Figure 5, starting symbol #1 is symbol #3 and starting symbol #2 is symbol #7.

The frequency-domain resources of CSI-RS resource 1 and CSI-RS resource 2 may be the same as those of CSI-RS resource 1 and CSI-RS resource 2 in Figure 3.

Consequently, the UE may determine the physical resource for the aggregated CSI-RS resource as shown in Figure 5, which includes the time-frequency resources of CSI-RS resource 1 and CSI-RS resource 2.

In some cases of Embodiment 1-3, the one or more component CSI-RS resources may share a same set of parameters, which may include at least one of:

· a third parameter (e.g., density as specified in 3GPP standard documents) indicating a CSI-RS frequency density of each CSI-RS port per PRB;

· a fourth parameter (e.g., freqBand as specified in 3GPP standard documents) indicating a frequency band for CSI-RS;

· a fifth parameter (e.g., powerControlOffset as specified in 3GPP standard documents) indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE;

· a sixth parameter (e.g., powerControlOffsetSS as specified in 3GPP standard documents) indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE;

· a seventh parameter (e.g., scramblingID as specified in 3GPP standard documents) indicating a scrambling ID of CSI-RS;

· an eighth parameter (e.g., periodicityAndOffset as specified in 3GPP standard documents) indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS; or

· a ninth parameter (e.g., qcl-InfoPeriodicCSI-RS as specified in 3GPP standard documents) containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

In some examples of Embodiment 1, multiple component CSI-RS resources may be obtained by one CSI-RS resource with multiple repetitions. The multiple repetitions of the CSI-RS resource may be repetitions in the time domain such as adjacent symbols, adjacent slots.

Embodiment 2

Embodiment 2 provides solutions for aggregating the one or more component CSI-RS resources in the frequency domain (referred to as a frequency-division multiplexing (FDM) scheme) , which may be divided into Embodiment 2-1 and Embodiment 2-2.

Embodiment 2-1

In Embodiment 2-1, the one or more component CSI-RS resources are frequency-division multiplexed on a PRB level (which is referred to as a PRB level FDM scheme) .

For the PRB level FDM scheme, one or more consecutive PRBs may be used for the one or more component CSI-RS resources, wherein each CSI-RS resource is configured in a corresponding PRB. The indication for indicating the one or more component CSI-RS resources may indicate a CSI-RS frequency density (e.g., denoted as ρ) of each CSI-RS port per PRB equal to 1/N for each of the one or more component CSI-RS resources or for the aggregated CSI-RS resource, wherein N is a number of the one or more component CSI-RS resources.

For example, in the case of two component CSI-RS resources, two consecutive PRBs can be used for the two component CSI-RS resources, where the PRB with a smaller index among the two consecutive PRBs is associated with the CSI-RS resource with a smaller index among the two component CSI-RS resources. In such example, the CSI-RS frequency density may be equal to 1/2.

In the case of 3 or 4 component CSI-RS resources, the indication may indicate a new value of 1/3 or 1/4 for the CSI-RS frequency density, respectively. The UE may expect that a PRB number in a frequency band is a multiple of 2 or 3 or 4 in the case that ρ is configured as 1/2 or 1/3 or 1/4, respectively.

Figure 6 illustrates an exemplary physical resource for an aggregated CSI-RS resource with 64 ports in accordance with aspects of the present disclosure.

In the example of Figure 6, two component CSI-RS resources with 32 ports (e.g., denoted as CSI-RS resource 1 and CSI-RS resource 2) are indicated. A frequency domain allocation for CSI-RS resource 1 and a frequency domain allocation for CSI-RS resource 2 may also be indicated. The frequency domain allocation for CSI-RS resource 1 indicates that CSI-RS resource 1 is included in PRB n, and indicates the frequency-domain resources of CSI-RS resource 1 in PRB n, which is the same as those of CSI-RS resource 1 in Figure 4. The frequency domain allocation for CSI-RS resource 2 indicates that CSI-RS resource 2 is included in PRB n+1, and indicates the frequency-domain resources of CSI-RS resource 2 in PRB n+1, which is the same as those of CSI-RS resource 2 in Figure 4.

The time-domain resources of CSI-RS resource 1 in PRB n are the same as those of CSI-RS resource 1 in Figure 4. The time-domain resources of CSI-RS resource 2 in PRB n+1 are the same as those of CSI-RS resource 2 in Figure 4. Although in the example of Figure 6, the locations of symbols in a slot for CSI-RS resource 1 and CSI-RS resource 2 are the same, it is contemplated that the locations of symbols in a slot for CSI-RS resource 1 and CSI-RS resource 2 may be different, which should not affect the principle of the present disclosure.

Consequently, the UE may determine the physical resource for the aggregated CSI-RS resource with 64 ports based on CSI-RS resource 1 and CSI-RS resource 2, which includes the time-frequency resources of CSI-RS resource 1 and CSI-RS resource 2.

In some cases of Embodiment 2-1, the one or more component CSI-RS resources may share a same set of parameters, which may include at least one of:

· a first parameter (e.g., nrofPorts as specified in 3GPP standard documents) indicating a number of ports;

· a second parameter (e.g., cdm-Type as specified in 3GPP standard documents) indicating a CDM type;

Embodiment 2-2

In Embodiment 2-2, a high dimension CDM, such as FD4 (i.e., FD-OCC length equal to 4) , may be introduced for the aggregated CSI-RS resource (which is referred to as FDM scheme with high dimension FD-OCC) . The high dimension CDM may increase a total transmit power from CDM-ed CSI-RS ports and improve channel estimation performance by achieving a spreading gain.

In some cases of Embodiment 2-2, the indication for indicating the component CSI-RS resources may indicate a CDM type for the aggregated CSI-RS resource. In some cases of Embodiment 2-2, the CDM type for the aggregated CSI-RS resource may be predefined.

In some cases, the CDM type for the aggregated CSI-RS resource may have a FD-OCC length equal to 4. For example, the CDM type may have a FD-OCC length equal to 4 and a TD-OCC length equal to 1 (which may be defined as "fd-CDM4" ) , or have a FD-OCC length equal to 4 and a TD-OCC length equal to 2 (which may be defined as "cdm8-FD4-TD2" ) , or have a FD-OCC length equal to 4 and a TD-OCC length equal to 4 (which may be defined as "cdm16-FD4-TD4" ) .

For "fd-CDM4, " exemplary OCC sequences (i.e., w_f (k′) and w_t (l′) ) are shown in Table 4, wherein k'= 0, 1, 2, 3 and l'= 0. The OCC sequences are used in the formulas as specified in section 7.4.1.5.2 in TS 38.211 to map the sequence of CSI-RS to the physical resources.

Table 4: OCC sequences w_f (k′) and w_t (l′) for fd-CDM4

For "cdm8-FD4-TD2, " exemplary OCC sequences (i.e., w_f (k′) and w_t (l′) ) are shown in Table 5, wherein k'= 0, 1, 2, 3 and l'= 0, 1. The OCC sequences are used in the formulas as specified in section 7.4.1.5.2 in TS 38.211 to map the sequence of CSI-RS to the physical resources.

Table 5: OCC sequences w_f (k′) and w_t (l′) for cdm8-FD4-TD2

For "cdm16-FD4-TD4, " exemplary OCC sequences (i.e., w_f (k′) and w_t (l′) ) are shown in Table 6, wherein k'= 0, 1, 2, 3 and l'= 0, 1, 2, 3. The OCC sequences are used in the formulas as specified in section 7.4.1.5.2 in TS 38.211 to map the sequence of CSI-RS to the physical resources.

Table 6: OCC sequences w_f (k′) and w_t (l′) for cdm16-FD4-TD4

In some cases of Embodiment 2-2, the indication for indicating the component CSI-RS resources may also indicate a CDM type for each component CSI-RS resource. In some other cases of Embodiment 2-2, the indication may not indicate a CDM type for each component CSI-RS resource, and the UE may derive the CDM type for each component CSI-RS resource from the CDM type for the aggregated CSI-RS resource.

To achieve the spreading gain, channels for multiple REs with OCC are assumed the same. Given this, consecutive resource elements (REs) in a same symbol from a component CSI-RS resource can be used in a CDM group for the aggregated CSI-RS resource.

The following Table 7 illustrates exemplary configurations for an aggregated CSI-RS resource with 64 ports when the CDM type for the aggregated CSI-RS resource is "fd-CDM4" , "cdm8-FD4-TD2" , and "cdm16-FD4-TD4" , respectively. In these CDM types, 4 consecutive subcarriers (or REs) in one PRB are used to support a FD OCC length of 4.

Table 7: Exemplary configurations for 64 port CSI-RS supporting additional CDM type

In Table 7, (k₀, l₀) , (k₁, l₀) , (k₀, l₀+1) , (k₁, l₀+1) , (k₀, l₁) , (k₁, l₁) , (k₀, l₁+1) , and (k₁, l₁+1) denote time-frequency resources from a first component CSI-RS resource in PRB set 0 (e.g., a PRB with an even index) , wherein k₀ and k₁ are two frequency locations in a PRB, and l₀ and l₁ are two starting symbols in a slot. anddenote time-frequency resources from a second component CSI-RS resource in PRB set 1 (e.g. a PRB with an odd index) , whereinandare two frequency locations in a PRB, andandare two starting symbols in a slot. Other parameters may have the same definitions as those in Table 7.4.1.5.3-1 specified in TS 38.211.

Figure 7 illustrates yet another exemplary physical resource for an aggregated CSI-RS resource with 64 ports in accordance with aspects of the present disclosure.

In the example of Figure 7, two component CSI-RS resources with 32 ports (e.g., denoted as CSI-RS resource 1 and CSI-RS resource 2) are indicated. The CDM type for the aggregated CSI-RS resource with 64 ports is "cdm8-FD4-TD2" .

The indication for indicating the component CSI-RS resources may indicate k₀ and k₁ (which are subcarrier #0 and subcarrier #6, respectively) in PRB n and l₀ and l₁ (which are symbol #6 and symbol #12, respectively) for CSI-RS resource 1. The indication may indicate and (which are subcarrier #0 and subcarrier #6, respectively) in PRB n+1 andand (which are symbol #6 and symbol #12, respectively) for CSI-RS resource 2. Although in the example of Figure 7, the locations of symbols in a slot for CSI-RS resource 1 and CSI-RS resource 2 are the same, it is contemplated that the locations of symbols in a slot for CSI-RS resource 1 and CSI-RS resource 2 may be different, which should not affect the principle of the present disclosure.

Based on Table 7, the frequency-domain resources and the time-domain resources for the aggregated CSI-RS resource are shown in Figure 7, wherein 4 consecutive REs in a same symbol from a component CSI-RS resource are used in a CDM group for the aggregated CSI-RS resource, e.g., to support a FD OCC length of 4.

In some cases of Embodiment 2-2, the one or more component CSI-RS resources may share a same set of parameters, which may include at least one of:

· a second parameter (e.g., density as specified in 3GPP standard documents) indicating a CSI-RS frequency density of each CSI-RS port per PRB;

· a third parameter (e.g., freqBand as specified in 3GPP standard documents) indicating a frequency band for CSI-RS;

· a fourth parameter (e.g., powerControlOffset as specified in 3GPP standard documents) indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE;

· a fifth parameter (e.g., powerControlOffsetSS as specified in 3GPP standard documents) indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE;

· a sixth parameter (e.g., scramblingID as specified in 3GPP standard documents) indicating a scrambling ID of CSI-RS;

· a seventh parameter (e.g., periodicityAndOffset as specified in 3GPP standard documents) indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS; or

· an eighth parameter (e.g., qcl-InfoPeriodicCSI-RS as specified in 3GPP standard documents) containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

In some examples of Embodiment 2, multiple component CSI-RS resources may be obtained by one CSI-RS resource with multiple repetitions. The multiple repetitions of the CSI-RS resource may be repetitions in the frequency domain such as adjacent PRBs.

Embodiment 3

Embodiment 3 provides solutions for aggregating the one or more component CSI-RS resources in the code/sequence domain. That is, the one or more component CSI-RS resources are code-division multiplexed on a sequence level (also referred to as a CDM scheme) .

In such embodiment, it is assumed that CSI-RS ports from different CSI-RS resources have good spatial orthogonality. Otherwise, there is strong interference between CSI-RS on the same time-frequency resource, and thus the channel estimation performance cannot be guaranteed.

In Embodiment 3, the same time-frequency resources are used for the one or more component CSI-RS resources but different sequences are used for the one or more component CSI-RS resources. To obtain different sequences for the one or more component CSI-RS resources, the indication for indicating the one or more component CSI-RS resources may indicate a different scrambling ID for each component CSI-RS resources to generate a CSI-RS sequence for each component CSI-RS resource, e.g., based on the formulas specified in section 7.4.1.5.2 in TS 38.211.

In some cases of Embodiment 3, the one or more component CSI-RS resources may share a same set of parameters, which may include at least one of:

· a third parameter (e.g., firstOFDMSymbolInTimeDomain as specified in 3GPP standard documents) indicating a first starting symbol for CSI-RS;

· a fourth parameter (e.g., firstOFDMSymbolInTimeDomain2as specified in 3GPP standard documents) indicating a second starting symbol for CSI-RS;

· a fifth parameter (e.g., cdm-Type as specified in 3GPP standard documents) indicating a CDM type;

· a sixth parameter (e.g., density as specified in 3GPP standard documents) indicating a CSI-RS frequency density of each CSI-RS port per PRB;

· a seventh parameter (e.g., freqBand as specified in 3GPP standard documents) indicating a frequency band for CSI-RS;

· an eighth parameter (e.g., powerControlOffset as specified in 3GPP standard documents) indicating an assumed ratio of PDSCH EPRE to NZP CSI-RS EPRE;

· a ninth parameter (e.g., powerControlOffsetSS as specified in 3GPP standard documents) indicating an assumed ratio of NZP CSI-RS EPRE to SSB EPRE;

· a tenth parameter (e.g., periodicityAndOffset as specified in 3GPP standard documents) indicating a CSI-RS periodicity and a slot offset for periodic or semi-persistent CSI-RS; or

· an eleventh parameter (e.g., qcl-InfoPeriodicCSI-RS as specified in 3GPP standard documents) containing a reference to a TCI state indicating QCL source reference signal (s) and QCL type (s) .

According to some embodiments of the present disclosure, at least two of the TDM scheme in Embodiment 1, the FDM scheme in Embodiment 2, or the CDM scheme in Embodiment 3 may be combined. For example, the combined schemes may be based on different scheduling scenarios, channel properties, etc. In some cases, the indication for indicating the one or more component CSI-RS resources may indicate at least one of the following multiplexing schemes for the one or more component CSI-RS resources: time-division multiplexing (e.g., any TDM scheme in Embodiment 1) , frequency-division multiplexing (e.g., any FDM scheme in Embodiment 2) , or CDM (e.g., the CDM scheme in Embodiment 3) .

In some examples, when the TDM scheme and the FDM scheme are combined, a new CSI-RS pattern may be generated based on a combination of TDM based CSI-RS pattern and FDM based CSI-RS pattern. In some examples, at least two of the one or more component CSI-RS resources are time-division multiplexed on a symbol level or a slot level and at least two of the one or more component CSI-RS resources are frequency-division multiplexed on a PRB level.

For example, in the case of the aggregated CSI-RS resource with 96 ports, the one or more component CSI-RS resources may include 3 component CSI-RS resources with 32 ports (e.g., denoted as CSI-RS resource 1, CSI-RS resource 2, and CSI-RS resource 3, respectively) . CSI-RS resource 1 and CSI-RS resource 2 may be time-division multiplexed on a symbol level or a slot level (e.g., in a manner as described in Embodiment 1) , and CSI-RS resource 1 and CSI-RS resource 3 may be frequency-division multiplexed on a PRB level (e.g., in a manner as described in Embodiment 2) .

In some examples, a new CSI-RS pattern may be generated based on component CSI-RS resources with different time-domain resources and different frequency-domain resources. For example, different OFDM symbols may be configured/specified for FDM-ed component CSI-RS resources and/or different PRBs may be configured/specified for TDM-ed component CSI-RS resources.

For the case that the TDM scheme and the FDM scheme are combined, in some embodiments, the one or more component CSI-RS resources may share a same set of parameters, which may include at least one of:

· an eighth parameter indicating a CSI-RS periodicity (e.g., periodicityAndOffset as specified in 3GPP standard documents) ; or

Embodiment 4

In Embodiment 4, the indication for indicating the one or more component CSI-RS resources may indicate only one CSI-RS resource. The UE may obtain the aggregated CSI-RS resource with more than 32 ports by the indicated CSI-RS resource with repetitions in the time domain or in the frequency domain.

In such embodiment, the indication may also indicate repetitions of the indicated CSI-RS resource in at least one of multiple symbols, multiple slots, or multiple PRBs to determine the aggregated CSI-RS resource. As an example, the multiple slots may be adjacent slots. As another example, the multiple PRBs may be consecutive PRBs.

Based on the time-frequency resources of the indicated CSI-RS resource and the indicated repetitions, the UE may determine the physical resource for the aggregated CSI-RS resource.

According to some embodiments of the present application, if the aggregated CSI-RS resource with more than 32 ports is an aperiodic CSI-RS resource, the one or more component CSI-RS resources for generating the aggregated CSI-RS resource with more than 32 ports may be assumed to be triggered simultaneously since they are parts of the aggregated CSI-RS resource.

In a wireless commination system, there may exist legacy UEs which only support a maximum number of CSI-RS ports equal to 32 and advanced UEs which support CSI-RS with more than 32 ports. In such system, a BS may transmit CSI-RS with more than 32 ports. For a legacy UE, it may only receive CSI-RS with a configured port number (i.e. no larger than 32) and perform rate matching for other CSI-RS ports by configuring zero power (ZP) CSI-RS to reduce performance impact on PDSCH.

Therefore, to facilitate ZP CSI-RS configuration for rate matching, the UEs need to determine the port indexes of more than 32 ports. In the embodiments of the present disclosure, the port indexes may be determined based on a CSI-RS resource index in addition to other factors considered when determining port indexes of no more than 32 ports.

In some embodiments, the UE may determine port indexes of the ports (e.g., more than 32 ports) for the aggregated CSI-RS resource first within the one or more component CSI-RS resources, then within a CDM group, and last across CDM groups in the frequency domain and then in the time domain

For example, the aggregated CSI-RS resource may be a CSI-RS resource with 64 ports, which is aggregated by two component CSI-RS resources with 32 ports. Then, the UE may determine port indexes for ports of a first component CSI-RS resource to be 0 to 31 (or to be smaller indexes) , and determine port indexes for ports of a second component CSI-RS resource to be 32 to 63 (or to be larger indexes) . For the port indexes within a component CSI-RS resource, a legacy CSI-RS port assignment scheme may be reused. For example, the UE may determine the port indexes within a CDM group first, then across CDM groups first in the frequency domain and then in the time domain.

As an example, the UE may assume that a CSI-RS is transmitted using antenna ports p numbered according to the following formula:

Wherein s is the sequence index in one CDM group, L is the CDM group size, K is the number of component CSI-RS resources, N_i is the number of CSI-RS ports for a CSI-RS resource with an index i, wherein 0≤i≤K-1. The CDM groups are numbered in an order of increasing frequency domain allocation first and then increasing time domain allocation.

Figure 8 illustrates a flowchart of an exemplary method in accordance with aspects of the present disclosure. The operations of the method illustrated in Figure 8 may be performed by a BS (e.g., NE 102 in Figure 1) as described herein or other apparatus with the like functions. In some implementations, the BS may execute a set of instructions to control functional elements of the BS to perform the described operations or functions.

As shown in Figure 8, in step 802, the BS may transmit an indication for indicating one or more CSI-RS resources.

In step 804, the BS may determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32.

In step 806, the BS may transmit CSI-RS on the determined physical resource.

All the definitions and operations related to the one or more CSI-RS resource, physical resource, aggregated CSI-RS resource described with respect to FIGS. 2-7 may also apply here. In addition, it is contemplated that the operations of the BS for determining a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources in step 804 may be the same as or similar to those performed by the UE as described with respect to FIGS. 2-7. Thus, details are omitted for simplicity.

In some embodiments of the present application, the BS may assign port indexes of the first number of ports first within the one or more CSI-RS resources, then within a CDM group, and last across CDM groups in the frequency domain and then in the time domain. The operations of the BS for assigning port indexes of the first number of ports may correspond to those performed by the UE for determining port indexes for the aggregated CSI-RS resource as described above. Thus, details are omitted for simplicity.

Figure 9 illustrates an example of a UE 900 in accordance with aspects of the present disclosure. The UE 900 may include at least one processor 902 and at least one memory 904. Additionally, the UE 900 may also include one or more of at least one controller 906 or at least one transceiver 908. The processor 902, the memory 904, the controller 906, or the transceiver 908, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 902, the memory 904, the controller 906, or the transceiver 908, or various combinations or components thereof may be implemented in hardware (e.g., circuitry) . The hardware may include a processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

The processor 902 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 902 may be configured to operate the memory 904. In some other implementations, the memory 904 may be integrated into the processor 902. The processor 902 may be configured to execute computer-readable instructions stored in the memory 904 to cause the UE 900 to perform various functions of the present disclosure.

The memory 904 may include volatile or non-volatile memory. The memory 904 may store computer-readable, computer-executable code including instructions when executed by the processor 902 cause the UE 900 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 904 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 902 and the memory 904 coupled with the processor 902 may be configured to cause the UE 900 to perform one or more of the functions described herein (e.g., executing, by the processor 902, instructions stored in the memory 904) . For example, the processor 902 may support wireless communication at the UE 900 in accordance with examples as disclosed herein. The UE 900 may be configured to support a means for performing the operations of the methods described in the embodiments of the present disclosure. In an embodiment, the processor 902 may be configured to cause the UE 900 to: receive an indication for indicating one or more CSI-RS resources; determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and receive CSI-RS on the determined physical resource.

The controller 906 may manage input and output signals for the UE 900. The controller 906 may also manage peripherals not integrated into the UE 900. In some implementations, the controller 906 may utilize an operating system such as or other operating systems. In some implementations, the controller 906 may be implemented as part of the processor 902.

In some implementations, the UE 900 may include at least one transceiver 908. In some other implementations, the UE 900 may have more than one transceiver 908. The transceiver 908 may represent a wireless transceiver. The transceiver 908 may include one or more receiver chains 910, one or more transmitter chains 912, or a combination thereof.

A receiver chain 910 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 910 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 910 may include at least one amplifier (e.g., a low-noise amplifier (LNA) ) configured to amplify the received signal. The receiver chain 910 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 910 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

A transmitter chain 912 may be configured to generate and transmit signals (e.g., control information, data, packets) . The transmitter chain 912 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM) , frequency modulation (FM) , or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM) . The transmitter chain 912 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 912 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

Figure 10 illustrates an example of a processor 1000 in accordance with aspects of the present disclosure. The processor 1000 may be an example of a processor configured to perform various operations in accordance with examples as described herein. The processor 1000 may include a controller 1002 configured to perform various operations in accordance with examples as described herein. The processor 1000 may optionally include at least one memory 1004, which may be, for example, a layer 1 (L1) , layer 2 (L2) , or layer 3 (L3) cache. Additionally, or alternatively, the processor 1000 may optionally include one or more arithmetic-logic units (ALUs) 1006. One or more of these components may be in electronic communication or otherwise coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces (e.g., buses) .

The processor 1000 may be a processor chipset and include a protocol stack (e.g., a software stack) executed by the processor chipset to perform various operations (e.g., receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) in accordance with examples as described herein. The processor chipset may include one or more cores, one or more caches (e.g., memory local to or included in the processor chipset (e.g., the processor 1000) or other memory (e.g., random access memory (RAM) , read-only memory (ROM) , dynamic RAM (DRAM) , synchronous dynamic RAM (SDRAM) , static RAM (SRAM) , ferroelectric RAM (FeRAM) , magnetic RAM (MRAM) , resistive RAM (RRAM) , flash memory, phase change memory (PCM) , and others) .

The controller 1002 may be configured to manage and coordinate various operations (e.g., signaling, receiving, obtaining, retrieving, transmitting, outputting, forwarding, storing, determining, identifying, accessing, writing, reading) of the processor 1000 to cause the processor 1000 to support various operations in accordance with examples as described herein. For example, the controller 1002 may operate as a control unit of the processor 1000, generating control signals that manage the operation of various components of the processor 1000. These control signals include enabling or disabling functional units, selecting data paths, initiating memory access, and coordinating timing of operations.

The controller 1002 may be configured to fetch (e.g., obtain, retrieve, receive) instructions from the memory 1004 and determine subsequent instruction (s) to be executed to cause the processor 1000 to support various operations in accordance with examples as described herein. The controller 1002 may be configured to track memory address of instructions associated with the memory 1004. The controller 1002 may be configured to decode instructions to determine the operation to be performed and the operands involved. For example, the controller 1002 may be configured to interpret the instruction and determine control signals to be output to other components of the processor 1000 to cause the processor 1000 to support various operations in accordance with examples as described herein. Additionally, or alternatively, the controller 1002 may be configured to manage flow of data within the processor 1000. The controller 1002 may be configured to control transfer of data between registers, ALUs, and other functional units of the processor 1000.

The memory 1004 may include one or more caches (e.g., memory local to or included in the processor 1000 or other memory, such RAM, ROM, DRAM, SDRAM, SRAM, MRAM, flash memory, etc. ) . In some implementations, the memory 1004 may reside within or on a processor chipset (e.g., local to the processor 1000) . In some other implementations, the memory 1004 may reside external to the processor chipset (e.g., remote to the processor 1000) .

The memory 1004 may store computer-readable, computer-executable code including instructions that, when executed by the processor 1000, cause the processor 1000 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as system memory or another type of memory. The controller 1002 and/or the processor 1000 may be configured to execute computer-readable instructions stored in the memory 1004 to cause the processor 1000 to perform various functions. For example, the processor 1000 and/or the controller 1002 may be coupled with or to the memory 1004, the processor 1000, the controller 1002, and the memory 1004 may be configured to perform various functions described herein. In some examples, the processor 1000 may include multiple processors and the memory 1004 may include multiple memories. One or more of the multiple processors may be coupled with one or more of the multiple memories, which may, individually or collectively, be configured to perform various functions herein.

The one or more ALUs 1006 may be configured to support various operations in accordance with examples as described herein. In some implementations, the one or more ALUs 1006 may reside within or on a processor chipset (e.g., the processor 1000) . In some other implementations, the one or more ALUs 1006 may reside external to the processor chipset (e.g., the processor 1000) . One or more ALUs 1006 may perform one or more computations such as addition, subtraction, multiplication, and division on data. For example, one or more ALUs 1006 may receive input operands and an operation code, which determines an operation to be executed. One or more ALUs 1006 be configured with a variety of logical and arithmetic circuits, including adders, subtractors, shifters, and logic gates, to process and manipulate the data according to the operation. Additionally, or alternatively, the one or more ALUs 1006 may support logical operations such as AND, OR, exclusive-OR (XOR) , not-OR (NOR) , and not-AND (NAND) , enabling the one or more ALUs 1006 to handle conditional operations, comparisons, and bitwise operations.

The processor 1000 may support wireless communication in accordance with examples as disclosed herein. The processor 1000 may be configured to or operable to support a means for performing the operations of the methods described in the embodiments of the present disclosure. In an embodiment, the controller 1002 may cause the processor 1000 to: receive an indication for indicating one or more CSI-RS resources; determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and receive CSI-RS on the determined physical resource.

Figure 11 illustrates an example of a BS 1100 in accordance with aspects of the present disclosure. The BS 1100 may include at least one processor 1102 and at least one memory 1104. Additionally, the BS 1100 may also include one or more of at least one controller 1106 or at least one transceiver 1108. The processor 1102, the memory 1104, the controller 1106, or the transceiver 1108, or various combinations thereof or various components thereof may be examples of means for performing various aspects of the present disclosure as described herein. These components may be coupled (e.g., operatively, communicatively, functionally, electronically, electrically) via one or more interfaces.

The processor 1102, the memory 1104, the controller 1106, or the transceiver 1108, or various combinations or components thereof may be implemented in hardware (e.g., circuitry) . The hardware may include a processor, a digital signal processor (DSP) , an application-specific integrated circuit (ASIC) , or other programmable logic device, or any combination thereof configured as or otherwise supporting a means for performing the functions described in the present disclosure.

The processor 1102 may include an intelligent hardware device (e.g., a general-purpose processor, a DSP, a CPU, an ASIC, an FPGA, or any combination thereof) . In some implementations, the processor 1102 may be configured to operate the memory 1104. In some other implementations, the memory 1104 may be integrated into the processor 1102. The processor 1102 may be configured to execute computer-readable instructions stored in the memory 1104 to cause the BS 1100 to perform various functions of the present disclosure.

The memory 1104 may include volatile or non-volatile memory. The memory 1104 may store computer-readable, computer-executable code including instructions when executed by the processor 1102 cause the BS 1100 to perform various functions described herein. The code may be stored in a non-transitory computer-readable medium such as the memory 1104 or another type of memory. Computer-readable media includes both non-transitory computer storage media and communication media including any medium that facilitates transfer of a computer program from one place to another. A non-transitory storage medium may be any available medium that may be accessed by a general-purpose or special-purpose computer.

In some implementations, the processor 1102 and the memory 1104 coupled with the processor 1102 may be configured to cause the BS 1100 to perform one or more of the functions described herein (e.g., executing, by the processor 1102, instructions stored in the memory 1104) . For example, the processor 1102 may support wireless communication at the BS 1100 in accordance with examples as disclosed herein. The BS 1100 may be configured to support a means for performing the operations of the methods described in the embodiments of the present disclosure. In an embodiment, the processor 1102 may be configured to cause the BS 1100 to: transmit an indication for indicating one or more CSI-RS resources; determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and transmit CSI-RS on the determined physical resource.

The controller 1106 may manage input and output signals for the BS 1100. The controller 1106 may also manage peripherals not integrated into the BS 1100. In some implementations, the controller 1106 may utilize an operating system such as or other operating systems. In some implementations, the controller 1106 may be implemented as part of the processor 1102.

In some implementations, the BS 1100 may include at least one transceiver 1108. In some other implementations, the BS 1100 may have more than one transceiver 1108. The transceiver 1108 may represent a wireless transceiver. The transceiver 1108 may include one or more receiver chains 1110, one or more transmitter chains 1112, or a combination thereof.

A receiver chain 1100 may be configured to receive signals (e.g., control information, data, packets) over a wireless medium. For example, the receiver chain 1110 may include one or more antennas for receive the signal over the air or wireless medium. The receiver chain 1110 may include at least one amplifier (e.g., a low-noise amplifier (LNA) ) configured to amplify the received signal. The receiver chain 1110 may include at least one demodulator configured to demodulate the receive signal and obtain the transmitted data by reversing the modulation technique applied during transmission of the signal. The receiver chain 1110 may include at least one decoder for decoding the demodulated signal to receive the transmitted data.

A transmitter chain 1112 may be configured to generate and transmit signals (e.g., control information, data, packets) . The transmitter chain 1112 may include at least one modulator for modulating data onto a carrier signal, preparing the signal for transmission over a wireless medium. The at least one modulator may be configured to support one or more techniques such as amplitude modulation (AM) , frequency modulation (FM) , or digital modulation schemes like phase-shift keying (PSK) or quadrature amplitude modulation (QAM) . The transmitter chain 1112 may also include at least one power amplifier configured to amplify the modulated signal to an appropriate power level suitable for transmission over the wireless medium. The transmitter chain 1112 may also include one or more antennas for transmitting the amplified signal into the air or wireless medium.

The description herein is provided to enable a person having ordinary skill in the art to make or use the disclosure. Various modifications to the disclosure will be apparent to a person having ordinary skill in the art, and the generic principles defined herein may be applied to other variations without departing from the scope of the disclosure. Thus, the disclosure is not limited to the examples and designs described herein but is to be accorded the broadest scope consistent with the principles and novel features disclosed herein.

Claims

A user equipment (UE) for wireless communication, comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the UE to:

receive an indication for indicating one or more channel state information reference signal (CSI-RS) resources;

determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and

receive CSI-RS on the determined physical resource.
The UE of Claim 1, wherein:

in the case of the aggregated CSI-RS resource with 48 ports, the one or more CSI-RS resources include two CSI-RS resources with 24 ports or three CSI-RS resources with 16 ports;

in the case of the aggregated CSI-RS resource with 64 ports, the one or more CSI-RS resources include two CSI-RS resources with 32 ports or four CSI-RS resources with 16 ports;

in the case of the aggregated CSI-RS resource with 72 ports, the one or more CSI-RS resources include:

three CSI-RS resources with 24 ports; or

one CSI-RS resource with 48 ports and one CSI-RS resource with 24 ports;

in the case of the aggregated CSI-RS resource with 96 ports, the one or more CSI-RS resources include:

three CSI-RS resources with 32 ports; or

one CSI-RS resource with 64 ports and one CSI-RS resource with 32 ports; or

in the case of the aggregated CSI-RS resource with 128 ports, the one or more CSI-RS resources include two CSI-RS resources with 64 ports or four CSI-RS resources with 32 ports.
The UE of Claim 1, wherein a configuration of (N₁, N₂) for an antenna array is supported by the UE with N₁ being a number of antenna ports per polarization direction in a horizontal direction and N₂ being a number of antenna ports per polarization direction in a vertical direction:

in the case of the aggregated CSI-RS resource with 48 ports, the configuration of (N₁, N₂) includes (8, 3) , (12, 2) , or (24, 1) ;

in the case of the aggregated CSI-RS resource with 64 ports, the configuration of (N₁, N₂) includes (8, 4) , (16, 2) , or (32, 1) ;

in the case of the aggregated CSI-RS resource with 72 ports, the configuration of (N₁, N₂) includes (12, 3) or (18, 2) ;

in the case of the aggregated CSI-RS resource with 96 ports, the configuration of (N₁, N₂) includes (16, 3) , (24, 2) or (48, 1) ; or

in the case of the aggregated CSI-RS resource with 128 ports, the configuration of (N₁, N₂) includes (8, 8) , (16, 4) , (32, 2) or (64, 1) .
The UE of Claim 1, wherein the one or more CSI-RS resources are time-division multiplexed on a symbol level or a slot level.
The UE of Claim 4, wherein the indication indicates different starting symbols in one slot for the one or more CSI-RS resources and there is no overlapping symbol among the one or more CSI-RS resources.
The UE of Claim 4, wherein the indication indicates same slot (s) or adjacent slots for CSI-RS resources.
The UE of Claim 1, wherein the indication indicates a CDM type for the aggregated CSI-RS resource.
The UE of Claim 7, wherein the CDM type has a frequency domain orthogonal cover code (FD-OCC) length equal to 2 and a time division orthogonal cover code (TD-OCC) length equal to 8, a FD-OCC length equal to 4 and a TD-OCC length equal to 1, a FD-OCC length equal to 4 and a TD-OCC length equal to 2, or a FD-OCC length equal to 4 and a TD-OCC length equal to 4.
The UE of Claim 7, wherein a space between starting symbols of two CSI-RS resources is equal to a TD-OCC length for a CSI-RS resource of the two CSI-RS resources.
The UE of Claim 1, wherein the one or more CSI-RS resources are frequency-division multiplexed on a physical resource block (PRB) level.
The UE of Claim 10, wherein the indication indicates a CSI-RS frequency density of each CSI-RS port per PRB equal to 1/N for each of the one or more CSI-RS resources or for the aggregated CSI-RS resource, wherein N is a number of the one or more CSI-RS resources.
The UE of Claim 7, wherein consecutive resource elements (REs) in a same symbol from a CSI-RS resource are used in a CDM group.
The UE of Claim 1, wherein at least two of the one or more CSI-RS resources are time-division multiplexed on a symbol level or a slot level and at least two of the one or more CSI-RS resources are frequency-division multiplexed on a PRB level.
The UE of Claim 4, 7, 10, or 13, wherein the indication indicates a same set of parameters for each of the one or more CSI-RS resources, wherein the same set of parameters includes at least one of:

a first parameter indicating a number of ports;

a second parameter indicating a CSI-RS frequency density of each CSI-RS port per PRB;

a third parameter indicating a frequency band for CSI-RS;

a fourth parameter indicating an assumed ratio of physical downlink shared channel (PDSCH) energy per resource element (EPRE) to non-zero-power (NZP) CSI-RS EPRE;

a fifth parameter indicating an assumed ratio of NZP CSI-RS EPRE to synchronization signal block (SSB) EPRE;

a sixth parameter indicating a scrambling identity (ID) of CSI-RS;

a seventh parameter indicating a CSI-RS periodicity; or

an eighth parameter containing a reference to a transmission configuration indicator (TCI) state indicating quasi co-located (QCL) source reference signal (s) and QCL type (s) .
The UE of Claim 1, wherein the indication indicates one CSI-RS resource, and the indication further indicates repetitions of the one CSI-RS resource in multiple symbols, multiple slots, or multiple PRBs to determine the aggregated CSI-RS resource.
The UE of claim 1, wherein the at least one processor is configured to cause the UE to determine port indexes of the first number of ports first within the one or more CSI-RS resources, then within a CDM group, and last across CDM groups in the frequency domain and then in the time domain.
The UE of claim 1, where the indication indicates at least one of the following multiplexing schemes for the one or more CSI-RS resources: time-division multiplexing, frequency-division multiplexing, or CDM.
A processor for wireless communication, comprising:

at least one controller coupled with at least one memory and configured to cause the processor to:

receive an indication for indicating one or more channel state information reference signal (CSI-RS) resources;

determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and

receive CSI-RS on the determined physical resource.
A base station (BS) for wireless communication, comprising:

at least one memory; and

at least one processor coupled with the at least one memory and configured to cause the BS to:

transmit an indication for indicating one or more channel state information reference signal (CSI-RS) resources;

determine a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and

transmit CSI-RS on the determined physical resource.
A method performed by a user equipment (UE) , the method comprising:

receiving an indication for indicating one or more channel state information reference signal (CSI-RS) resources;

determining a physical resource for an aggregated CSI-RS resource with a first number of ports based on the one or more CSI-RS resources, wherein the first number is more than 32; and

receiving CSI-RS on the determined physical resource.