WO2024000607A1

WO2024000607A1 - Method and apparatus for reference signal port resource configuration

Info

Publication number: WO2024000607A1
Application number: PCT/CN2022/103496
Authority: WO
Inventors: Hao Liu; Filippo Tosato; Tao Yang; Yan Zhao
Original assignee: Nokia Shanghai Bell Co., Ltd.; Nokia Solutions And Networks Oy; Nokia Technologies Oy
Priority date: 2022-07-01
Filing date: 2022-07-01
Publication date: 2024-01-04

Abstract

Embodiments of the present disclosure disclose a method and apparatus for Reference Signal, RS, port resource configuration in a multiple transmission and reception point scenario. A terminal device receives a coherent joint transmission, CJT, configuration indicating information on RS port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences. Then, the terminal device measures the associated RS port resources based on the CJT configuration. In this way, the terminal device only measures the partial RS port resources as configured without estimating the whole available RS port resources. Therefore, the terminal device may have lower channel measurement complexity.

Description

METHOD AND APPARATUS FOR REFERENCE SIGNAL PORT RESOURCE CONFIGURATION

FIELD

Embodiments of the present disclosure generally relate to the field of communication, and in particular, to a method, devices, apparatus and computer readable storage medium for reference signal (RS) port resource configuration.

BACKGROUND

With the development of communication technology, coherent joint transmission (CJT) for multiple transmit-receive points (TRPs) has been introduced to improve communication robustness and transmission efficiency. For the CJT, a layer is transmitted coherently from multiple TRPs. Hence, a terminal device needs to acquire the integrated downlink channel matrices across multiple TRPs by configuring one or more non-zero power (NZP) , channel state information reference signal, CSI-RS, resources.

In a possible solution for the CJT, a single CSI-RS resource may be configured for a terminal device to support downlink channel measurement across the maximum number of coordinated TRPs. The single CSI-RS resource may comprise a plurality of subsets, each associated with a different TRP. However, in such a solution, there is a need to enhance CSI-RS resource configuration to improve communication efficiency.

SUMMARY

In general, example embodiments of the present disclosure provide a method, apparatus and computer readable storage medium for channel state information reference signal (CSI-RS) resource configuration.

In a first aspect, there is provided a terminal device. The terminal device may comprise one or more transceivers; and one or more processors. The one or more processors are communicatively coupled to the one or more transceivers, and the one or more processors are configured to cause the terminal device to receive a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and measure the associated RS port resources based on the CJT configuration.

In a second aspect, there is provided a network device. The network device may comprise one or more transceivers; one or more processors. The one or more processors are communicatively coupled to the one or more transceivers, and the one or more processors are configured to cause the network device to transmit a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and receive a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.

In a third aspect, there is provided a method implemented at a terminal device. The method may comprise receiving a coherent joint transmission, CJT, configuration indicating information on RS port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and measuring the associated RS port resources based on the CJT configuration.

In a fourth aspect, there is provided a method implemented at a network device. The method may comprise transmitting a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and receiving a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.

In a fifth aspect, there is provided an apparatus of a terminal device. The apparatus may comprise means for receiving a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and means for measuring associated RS port resources based on the CJT configuration.

In a sixth aspect, there is provided an apparatus of a network device. The apparatus may comprise means for transmitting a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and means for receiving a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.

In a seventh aspect, there is provided a terminal device. The terminal device may comprise at least one processor; and at least one memory including computer program codes, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the terminal device to receive a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and measure associated RS port resources based on the CJT configuration.

In an eighth aspect, there is provided a network device. The network device may comprise at least one processor; and at least one memory including computer program codes, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to transmit a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and receive a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.

In a ninth aspect, there is provided a non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method according to the third or fourth aspect.

It is to be understood that the summary section is not intended to identify key or essential features of embodiments of the present disclosure, nor is it intended to be used to limit the scope of the present disclosure. Other features of the present disclosure will become easily comprehensible through the following description.

BRIEF DESCRIPTION OF THE DRAWINGS

Some example embodiments will now be described with reference to the accompanying drawings, where:

Fig. 1 illustrates an example network environment in which example embodiments of the present disclosure may be implemented;

Fig. 2 illustrates a flowchart of a method implemented at a terminal device according to some embodiments of the present disclosure;

Fig. 3 illustrates an example port resource group configuration which can be used in example embodiments of the present disclosure;

Fig. 4 illustrates a flowchart of a method implemented at a network device according to some other embodiments of the present disclosure;

Fig. 5 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

Fig. 6 illustrates a block diagram of an example computer readable medium in accordance with some embodiments of the present disclosure.

Throughout the drawings, the same or similar reference numerals represent the same or similar element.

DETAILED DESCRIPTION

Principle of the present disclosure will now be described with reference to some example embodiments. It is to be understood that these embodiments are described only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitation as to the scope of the disclosure. The disclosure described herein can be implemented in various manners other than the ones described below.

In the following description and claims, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skills in the art to which this disclosure belongs.

References in the present disclosure to “one embodiment, ” “an embodiment, ” “an example embodiment, ” and the like indicate that the embodiment described may include a particular feature, structure, or characteristic, but it is not necessary that every embodiment includes the particular feature, structure, or characteristic. Moreover, such phrases are not necessarily referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with an embodiment, it is submitted that it is within the knowledge of one skilled in the art to affect such feature, structure, or characteristic in connection with other embodiments whether or not explicitly described.

It shall be understood that although the terms “first” and “second” etc. may be used herein to describe various elements, these elements should not be limited by these terms. These terms are only used to distinguish one element from another. For example, a first element could be termed a second element, and similarly, a second element could be termed a first element, without departing from the scope of example embodiments. As used herein, the term “and/or” includes any and all combinations of one or more of the listed terms.

The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of example embodiments. As used herein, the singular forms “a” , “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” , “comprising” , “has” , “having” , “includes” and/or “including” , when used herein, specify the presence of stated features, elements, and/or components etc., but do not preclude the presence or addition of one or more other features, elements, components and/or combinations thereof.

As used in this application, the term “circuitry” may refer to one or more or all of the following:

(a) hardware-only circuit implementations (such as implementations in only analog and/or digital circuitry) and

(b) combinations of hardware circuits and software, such as (as applicable) :

(i) a combination of analog and/or digital hardware circuit (s) with software/firmware and

(ii) any portions of hardware processor (s) with software (including digital signal processor (s) ) , software, and memory (ies) that work together to cause an apparatus, such as a mobile phone or server, to perform various functions) and

(c) hardware circuit (s) and or processor (s) , such as a microprocessor (s) or a portion of a microprocessor (s) that requires software (e.g., firmware) for operation, but the software may not be present when it is not needed for operation.

This definition of circuitry applies to all uses of this term in this application, including in any claims. As a further example, as used in this application, the term circuitry also covers an implementation of merely a hardware circuit or processor (or multiple processors) or portion of a hardware circuit or processor and its (or their) accompanying software and/or firmware. The term circuitry also covers, for example and if applicable to the particular claim element, a baseband integrated circuit or processor integrated circuit for a mobile device or a similar integrated circuit in server, a cellular network device, or other computing or network device.

As used herein, the term “communication network” refers to a network following any suitable communication standards, such as Long Term Evolution (LTE) , LTE-Advanced (LTE-A) , Wideband Code Division Multiple Access (WCDMA) , High-Speed Packet Access (HSPA) , Narrow Band Internet of Things (NB-IoT) and so on. Furthermore, the communications between a terminal device and a network device in the communication network may be performed according to any suitable generation communication protocols, including, but not limited to, the third generation (3G) , the fourth generation (4G) , 4.5G, the fifth generation (5G) communication protocols, and/or beyond. Embodiments of the present disclosure may be applied in various communication systems. Given the rapid development in communications, there will of course also be future type communication technologies and systems with which the present disclosure may be embodied. It should not be seen as limiting the scope of the present disclosure to only the aforementioned system.

As used herein, the term “network device” refers to a node in a communication network via which a terminal device accesses the network and receives services therefrom. The network device may refer to a base station (BS) or an access point (AP) , for example, a node B (NodeB or NB) , an evolved NodeB (eNodeB or eNB) , a NR NB (also referred to as a gNB) , a Remote Radio Unit (RRU) , a radio header (RH) , a remote radio head (RRH) , a relay, a low power node such as a femto, a pico, and so forth, depending on the applied terminology and technology.

The term “terminal device” refers to any end device that may be capable of wireless communication. By way of example rather than limitation, a terminal device may also be referred to as a communication device, user equipment (UE) , a Subscriber Station (SS) , a Portable Subscriber Station, a Mobile Station (MS) , or an Access Terminal (AT) . The terminal device may include, but not limited to, a mobile phone, a cellular phone, a smart phone, voice over IP (VoIP) phones, wireless local loop phones, a tablet, a wearable terminal device, a personal digital assistant (PDA) , portable computers, desktop computer, image capture terminal devices such as digital cameras, gaming terminal devices, music storage and playback appliances, vehicle-mounted wireless terminal devices, wireless endpoints, mobile stations, laptop-embedded equipment (LEE) , laptop-mounted equipment (LME) , USB dongles, smart devices, wireless customer-premises equipment (CPE) , an Internet of Things (loT) device, a watch or other wearable, a head-mounted display (HMD) , a vehicle, a drone, a medical device and applications (e.g., remote surgery) , an industrial device and applications (e.g., a robot and/or other wireless devices operating in an industrial and/or an automated processing chain contexts) , a consumer electronics device, a device operating on commercial and/or industrial wireless networks, and the like. In the following description, the terms “terminal device” , “communication device” , “terminal” , “user equipment” and “UE” may be used interchangeably.

As used herein, the term “TRP” refers to a transmit-receive point having an antenna array (with one or more antenna elements) at the network side located at a specific geographical location, which may be used for transmitting and/or receiving signals to/from the terminal device. In an embodiment of the present disclosure, a TRP may refer to network equipment with physical functionalities, including but not limited to Macro Cell, micro cell, an RRH, an Integrated Access and Backhaul (IAB) node, a relay, a femto node, a pico node, etc. The physical functionalities may include for example coding/decoding, precoding, modulation/demodulation, etc. Although some embodiments of the present disclosure are described with reference to four TRPs for example, these embodiments are only for the purpose of illustration and help those skilled in the art to understand and implement the present disclosure, without suggesting any limitations as to the scope of the present disclosure. It is to be understood that the present disclosure described herein can be implemented in various manners other than the ones described below.

As used herein, the term “the RS (CSI-RS) resource” may indicate resources available for RS (CSI-RS) transmission in time domain, frequency domain and code domain. A single RS (CSI-RS) resource may support a plurality of ports (for example 32) and each port may be called as a RS port. A RS (CSI-RS) port resource may include one or more resource elements (REs) in a RS resource and/or code resource for the one or more REs and/or antenna elements which form a RS port. The plurality of ports may be further divided into port resource groups; each port resource group may correspond to a different TRP and include one or more ports for the TRP. The TRP may correspond to a specific transmission configuration indication (TCI) , or a TCI may be used to identify a specific TRP. It is possible that each port resource group may correspond to a TCI. TRP and TCI may be used interchangeably in the present disclosure.

As used herein, the term “CDM” refers to a multiplexing method that uses the orthogonal cover code (OCC) to distinguish each original signal, so that multiple CSI-RS ports can share the same time-frequency resource, in particular resource elements (REs) as defined in 3GPP TS 38.211. The CDM may have multiple types, such as noCDM (size 1, mapped onto only one resource element, RE) , fd-CDM2 (size 2, spread over 2 REs in the frequency domain, FD) , cdm4-FD2-TD2 (size 4, spread over 2 REs in FD and 2 REs, in the time domain, TD) and cdm8-FD2-TD4 (size 8, spread over 2REs in FD and 4REs in TD) . The CDM type may be obtained from the parameter cdm-Type in RRC.

As used herein, the term “CDM group” may correspond to a specific CDM type such as noCDM, fd-CDM2, cdm4-FD2-TD2, or cdm8-FD2-TD4. The term “CDM group size” means the number of CDM sequences per CDM group. The CDM sequences refer to the OCCs used in CDM. Multiple CSI-RS ports can be multiplexed in the CDM group and more CSI-RS ports can be supported by using more than one CDM group.

As mentioned above, in a possible solution for the CJT, a single CSI-RS resource may be configured for a terminal device to support downlink channel measurement across the maximum number of coordinated TRPs. The single CSI-RS resource may comprise a plurality of subsets each associated with a different TRP, wherein the TRP may be identified by for example, TCI.

For example, according to Technical Specification (TS) 38.211, the terminal device shall assume that a CSI-RS is transmitted using antenna ports p numbered according to the following equations and subsequent Table 1:

p=3000+s+jL (1)

j=0, 1, …, N/L-1

s=0, 1, …, L-1

Where,

· L∈ {1, 2, 4, 8} is the CDM group size (or the number of CDM sequences per CDM group) , s is the CDM sequence index provided by, e.g., Tables 2 for L=4, and N is the total number of CSI-RS ports.

· The CDM group index j given in Table 1 corresponds to the time/frequency locations

for a given row of the table.

· The CDM groups are numbered in order of increasing frequency domain allocation first and then increasing time domain allocation.

· The indices k' and l' index REs within a CDM group.

· The time domain locations l ₀ or l ₁ and frequency domain locations k _iare provided by higher-layer parameters.

· The total number of CSI-RS ports N equals to the number of CDM group (N/L) multiplied by the size of a CDM group (L) .

Example Table 1 for CSI-RS locations and Table 2 for CDM sequences are given as follows for illustrative purposes.

Table 1: CSI-RS locations within a slot (Table 7.4.1.5.3-1 in TS 38.211)

Table 2 The sequences w _f (k′) and w _t (l′) for cdm-Type equal to 'cdm4-FD2-TD2'

(Table 7.4.1.5.3-4 in TS 38.211)

Index	[w _f (0) w _f (1) ]	[w _t (0) w _t (1) ]
0	[+1 +1]	[+1 +1]
1	[+1 -1]	[+1 +1]
2	[+1 +1]	[+1 -1]
3	[+1 -1]	[+1 -1]

Normally, the terminal device needs to measure the complete CSI-RS port resources as specified in the current specification, extract the partial port resource groups according to the indication of actually served TRPs or serving cells and then report the corresponding precoding matrix indicator (PMI) to gNB side. However, in such a solution, there is a need to enhance CSI-RS resource configuration to improve communication efficiency.

According to embodiments of the present disclosure, there is a solution provided for CSI-RS port resource configuration. In this solution, a terminal device receives a CJT configuration indicating information on RS port resources to be measured. The information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences. Moreover, the terminal device measures the associated RS port resources based on the CJT configuration. As such, in embodiments of the present disclosure, the terminal device can be directly configured with a specific part of CSI-RS ports within the CSI-RS port resource in terms of actually served TRPs, and then the UE only measures the partial CSI-RS ports as indicated in the CJT configuration without estimating the whole CSI-RS ports of the CSI-RS port resource. Therefore, the terminal device has lower channel measurement complexity.

Example embodiments of the present disclosure for CSI-RS port resource configuration will be described below with reference to FIGS. 1-6.

Fig. 1 illustrates an example network environment 100 in which example embodiments of the present disclosure may be implemented. The environment 100, which may be a part of a communication network, comprises terminal devices and network devices.

As illustrated in Fig. 1, the network environment 100 may comprise a first device 110 (hereinafter may also be referred to as a UE 110 or a terminal device 110) . The network environment 100 may also comprise a second device 120, a third device 130, a fourth device 140, a fifth device 150 (hereinafter may also be referred to as

network devices

120, 130, 140 and 150, or TRPs120, 130, 140 and 150, or the like. The terminal device 110 may be configured to be communicated with network via one or more of the

TRPs

120, 130, 140 and 150. In the CJT, a terminal device may be served by one or more of

TRPs

120, 130, 140 and 150 at the same time. In the network environment 100, a link from the terminal device 110 to the network device 120 is referred to as an uplink, UL or a reverse link, while a link from the network device 120 to the terminal device 110 is referred to as a downlink, DL or a forward link.

It is to be understood that the number of network devices, terminal devices, or TRPs is only for the purpose of illustration without suggesting any limitations. The system 100 may include any suitable number of network devices, terminal devices, or TRPs adapted for implementing embodiments of the present disclosure. Although not shown, it would be appreciated that one or more terminal devices may be located in environment 100.

Communications in the network environment 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, the third generation (3G) , the fourth generation (4G) , the fifth generation (5G) or 5G beyond, wireless local network communication protocols such as Institute for Electrical and Electronics Engineers (IEEE) 802.11 and the like, and/or any other protocols currently known or to be developed in the future. Moreover, the communication may utilize any proper wireless communication technology, comprising but not limited to: Multiple-Input Multiple-Output (MIMO) , Orthogonal Frequency Division Multiplexing (OFDM) , time division multiplexing (TDM) , frequency division multiplexing (FDM) , code division multiplexing (CDM) , Bluetooth, ZigBee, and machine type communication (MTC) , enhanced mobile broadband (eMBB) , massive machine type communication (mMTC) , ultra-reliable low latency communication (URLLC) , Carrier Aggregation (CA) , Dual Connection (DC) , and New Radio Unlicensed (NR-U) technologies.

Fig. 2 illustrates a flowchart of method 200 implemented at a terminal device according to some embodiments of the present disclosure. For the purpose of discussion, method 200 will be described from the perspective of the terminal device 110 with reference to Fig. 1. It is to be understood that method 200 may further include additional blocks not shown and/or omit some shown blocks, and the scope of the present disclosure is not limited in this regard.

At block 210, the terminal device 110 may receive a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences. In other words, the terminal device may obtain information on which RS port needs to be measured based on the CJT configuration. It is to be noted that CJT configuration is only named for illustrative and the present disclosed is not limited there to; it may also be called as a configuration for CJT, a RS measurement configuration, a first configuration, or the like.

In some embodiments, the CJT configuration may be indicated by means of Medium Access Control Control Element, MAC CE. In other embodiments, the CJT configuration may be indicated by means of a Downlink Control Indication, DCI.

In some embodiments, the terminal device 100 may be configured to be communicated with one or more of multiple Transmission Reception Points, TRPs for the CJT. The RS port resources to be measured are at least a part of RS port resources available for multiple TRPs (for example totally 32 ports in the CSI-RS resource) . The RS port resources available for the multiple TRPs comprise a plurality of RS port resource groups, each RS port resource group may correspond to one of the multiple TRPs, and each RS port resource group may be associated with one of one or more subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences.

For example, the terminal device 110 may be configured to communicate with four TRPs, and there may be 32 RS ports available for the four TRPs. In such a case, the 32 RS ports may be divided evenly or unevenly into 4 RS port resource groups, each RS port resource group corresponds to one TRP.

In some embodiments, the information on RS port resources to be measured may comprise any of: one or more indices of RS port resource groups; one or more indices of TRPs, each associated with a RS port resource group; or one or more transmission configuration indication, TCI, state identifiers each being associated with a RS port resource group or TRP. In other words, indices of RS port resource groups, indices of TRPs, or TCI state identifiers may be directly or indirectly associated with a subset of the RS port resources.

As mentioned above in for example equation 1) , the RS ports can be determined based on CDM group index j and the CDM sequence index s. Thus, an association between any of the RS port resource groups, the TRPs, or the TCIs and subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences can be provided. In such a case, the terminal device may know the indices of CDM groups, or the indices of CDM sequences, or their both from the information in the CJT configuration and in turn determines the CSI-RS ports to be measured based on equation 1) .

The association may be a predetermined table known by both the terminal device and the network device. Or alternatively, it may be configured to the terminal device through for example a Radio Resource Control, RRC, signaling and/or MAC CE.

In some embodiments, the terminal device may be further caused to obtain a RS port resource association configuration indicating an association between any of the RS port resource groups, the TRPs, or the TCIs and subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences. Please be noted that the RS port resource association configuration is only named for illustration purposes and the present disclosure is not limited thereto. As an example, it may also be called as an RS port association configuration, CDM parameter association configuration, an association configuration, a second configuration, or any other suitable name.

It is to be noted that the subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences may be associated with any of the RS port resource groups, the TRPs, or the TCIs. Only for illustrative purposes, mapping of RS port resource groups to CDM groups or CDM sequences will be taken as an example to describe an example implementation.

Example Implementation 1-Port resource group configuration based on CDM groups

In an example, the terminal device 110 may be configured to communicate with 4 TRPs, and there may be 32 RS ports available for the four TRPs. The CDM group size L may be for example 4, and 8 CDM groups are required, with indices from 0 to 7. The 32 RS ports may be evenly divided into 4 RS port resource groups with indices from 0 to 3, and each RS port resource group corresponds to one TRP. The 4 port resource groups may be associated with 8 CDM groups, and each port resource group may be mapped to 2 CDM groups.

In such cases, the mapping relation between port resource groups and CDM groups (in turn CSI-RS ports) may be given below according top=3000+s+4j where s=0, 1, …, L-1 and L=4.

port resource group #0 is associated with CDM group indices j∈ {0, 1} , and

CSI-RS port indices correspond to {3000, 3001, 3002, 3003, 3004, 3005, 3006, 3007} .

port resource group #1 is associated with CDM group indices j∈ {2, 3} , and

CSI-RS port indices correspond to {3008, 3009, 3010, 3011, 3012, 3013, 3014, 3015} .

port resource group #2 is associated with CDM group indices j∈ {4, 5} , and

CSI-RS port indices correspond to {3016, 3017, 3018, 3019, 3020, 3021, 3022, 3023} .

port resource group #3 is associated with CDM group indices j∈ {6, 7} , and

CSI-RS port indices correspond to {3024, 3025, 3026, 3027, 3028, 3029, 3030, 3031} .

In the above embodiments, the RS port resource groups may comprise the same number of RS port resources. While the RS port resource groups may comprise different numbers of RS port resources. In some embodiments, different TRPs may support different numbers of CSI-RS ports, which means each TRP or port resource group can be mapped to a subset of CDM groups of unequal size. For example, port resource group #0 may be mapped to CDM group {0, 1, 2} , port resource group #1 may be mapped to CDM group {3} , port resource group #2 may be mapped to CDM group {4, 5, 6} , and port resource group #3 may be mapped to CDM group {7} .

Example Implementation 2-Port resource group configuration based on CDM sequences

In the example, similarly to Example Implementation 1, the terminal device 110 may be configured to communicate with 4 TRPs, and there may be 32 RS ports available for the four TRPs. The CDM group size L=4 and 8 CDM groups are required, with indices from 0 to 7. Differently, the 32 RS ports may be evenly divided into 4 RS port resource groups with indices from 0 to 3, each corresponding to one TRP. The 4 port resource groups may be associated with 4 CDM sequences, and each port resource group may be mapped to one CDM sequence.

In such cases, the mapping relation between port resource group and CSI-RS ports may be given below according to p=3000+s+4j, where j=0, 1, …, N/L-1 and N=32, L=4.

port resource group #0 is associated with CDM sequence s=0

CSI-RS port indices correspond to {3000, 3004, 3008, 3012, 3016, 3020, 3024, 3028} .

port resource group #1 is associated with CDM sequence s=1

CSI-RS port indices correspond to {3001, 3005, 3009, 3013, 3017, 3021, 3025, 3029} .

port resource group #2 is associated with CDM sequence s=2

CSI-RS port indices correspond to {3002, 3006, 3010, 3014, 3018, 3022, 3026, 3030} .

port resource group #3 is associated with CDM sequence s=3

CSI-RS port indices correspond to {3003, 3007, 3011, 3015, 3019, 3023, 3027, 3031} .

Please be noted that there might be some exceptions for Example Implementation 2. In an example, if the CDM group size L=1, it may use Example Implementation 1, instead. In other words, the port resource groups may be associated with CDM groups instead of one CDM sequence.

In another example, if CDM group size L=2, 4, port resource groups may be configured based on such as 2 CDM groups and 2 CDM sequences simultaneously. In other words, the association can be made between port resource groups and combinations of CDM groups and CDM sequences.

In yet another example, the terminal device 110 may be configured to be communicated with three TRPs, the 32 RS ports may be divided into 3 RS port resource groups, each RS port resource group corresponds to one TRP. 3 port resource groups cannot be mapped to L CDM sequences uniformly due to L∈ {1, 2, 4, 8} . In this case, the port resource groups may be associated with CDM groups instead of CDM sequences.

Example Implementation 3-Port resource group configuration based on CDM groups and CDM sequences

In the example, similarly to the above two example implementations, the terminal device 110 may be configured to communicate with four TRPs, and there may be 32 RS ports available for the four TRPs. The CDM group size L=4 and 8 CDM groups are required, with indices from 0 to 7. Differently, the 32 RS ports may be evenly divided into 4 RS port resource groups with indices from 0 to 3, each corresponding to one TRP. The 4 port resource groups may be associated with a combination of CDM groups and CDM sequences, as shown in Figure 3. Each port resource group is mapped to 4 CDM groups and 2 CDM sequences.

In such cases, then the mapping relation between port resource group and CSI-RS ports may be given below according to p=3000+s+4j, where s=0, …, 3 and j=0, …, 7.

port resource group #0 is associated with CDM group indices j∈ {0, 1, 2, 3} and CDM sequence s∈ {0, 1}

CSI-RS port indices correspond to {3000, 3001, 3004, 3005, 3008, 3009, 3012, 3013} .

port resource group #1 is associated with CDM group indices j∈ {0, 1, 2, 3} and CDM sequence s∈ {2, 3}

CSI-RS port indices correspond to {3002, 3003, 3006, 3007, 3010, 3011, 3014, 3015} .

port resource group #2 is associated with CDM group indices j∈ {4, 5, 6, 7} and CDM sequence s∈ {0, 1}

CSI-RS port indices correspond to {3016, 3017, 3020, 3021, 3024, 3025, 3028, 3029} .

port resource group #3 is associated with CDM group indices j∈ {4, 5, 6, 7} and CDM sequence s∈ {2, 3}

CSI-RS port indices correspond to {3018, 3019, 3022, 3023, 3026, 3027, 3030, 3031} .

In another example, different TRPs may have different numbers of CSI-RS ports, and in such a case each TRP or port resource group can be mapped to a different subset of the combination of CDM groups and CDM sequences with unequal size, adapted to the port number of the TRP.

Reference is then made back to Fig. 2, at block 220, the terminal device 110 may measure the associated RS port resources based on the CJT configuration.

In some embodiments, the RS port resources to be measured as indicated in the CJT configuration are determined based on the information on RS port resources to be measured and the association as indicated in the RS port resource association configuration.

In some other embodiments, the terminal device 110 is further caused to receive another CJT configuration indicating indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences. The indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences as indicated in this another CJT configuration may correspond to a subset of RS port resources associated with information on RS port resources to be measured (such as indices of TRPs, indices of port resource groups, or TCI status indicators) as indicated in the previous CJT configuration (i.e., the CJT configuration as described with reference to block 210) . Please be noted that the another CJT configuration is named only for illustrative purposes and the present disclosure is not limited thereto. Alternatively, it may also be called as another configuration for CJT, another RS measurement configuration, a third configuration, or the like.

In some embodiments, the CJT configuration may be received by means of Medium Access Control Control Element, MAC CE. In other embodiments, the CJT configuration may be received by means of a Downlink Control Indication, DCI.

In some embodiments, the another CJT configuration may be contained within the same MAC CE together with the CJT configuration as described in block 210. Or additionally, they can be carried in separate MAC CEs or separate signals.

In an example, the mapping relation has been specified in RRC signaling, the indices of TRP, the indices of port resource groups, or the indices of TCI status indicator to be measured have been indicated in L2 MAC CE, then the indices of CDM groups associated with the actually measured ports may be further indicated by the bitmap or combinatorial signaling at another L2 MAC CE according to the mapping relation for the coordinated TRPs or port resource groups indicated above. For example, the number of CDM groups for TRP i is L _i according to RRC signaling, but the actually configured number is x for CDM groups then

gNB may configure a bitmap having x “1” out of L _i bits and “0” elsewhere, or a combinatorial signaling by

bits for CDM groups.

In another example, the mapping relation has been specified in RRC signaling, indices of TRP, the indices of port resource groups, or the indices of TCI status indicator to be measured has been indicated in L2 MAC CE, and then the indices of CDM sequences associated with the actually measured ports may further be indicated by the bitmap or combinatorial signaling at another L2 MAC CE according to the mapping relation for the coordinated TRPs or port resource groups indicated above. For example, the number of CDM sequences is M _i according to RRC signaling, but the actually configured number is y for CDM sequences, then

gNB configures a bitmap having y “1” out of M _i bits and “0” elsewhere, or a combinatorial signaling by

bits for CDM sequences.

In a further embodiment, both indices of CDM groups and CDM sequences associated with the actually measured ports may further be indicated by the bitmap or combinatorial signaling at another L2 MAC CE according to the mapping relation for the coordinated TRPs or port resource groups indicated above. The bit map or combinatorial signaling can be implemented in a similar way to those described above in the previous two paragraphs.

In such a case, RS port resources to be measured actually may be determined based on the information on RS port resources to be measured as indicated in the CJT configuration, the association as indicated in the RS port resource association configuration and the indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences as indicated in the another CJT configuration. Thus, the network device 120 may configure less CSI-RS ports than usual, considering low implementation complexity at UE side or power saving at gNB side.

Herein above, some embodiments based on the CSI-RS port resource association are described and in some other embodiments, the information on RS port resources to be measured as described in block 210 may be implemented in a different way, without no any mapping relation or association.

In some embodiments, the information on RS port resources to be measured as described in 210 may directly comprise indices of CDM groups, indices of CDM sequences, or both indices of CDM groups and CDM sequences. Thus, the terminal device may learn the CSI-RS ports as indicated based on equation 1) .

In some embodiments, there is no mapping relation has been specified, the CDM groups to be measured has been indicated in L2 MAC CE, the indices of CDM groups associated with the actually measured ports can also be indicated by a bitmap or combinatorial signaling. For example, there are N CSI-RS ports and L CDM sequences per CDM group, so there are

CDM groups. If the actually configured number is x for CDM groups, then

gNB may configure a bitmap having x “1” out of

bits and “0” elsewhere, or a combinatorial signaling by

bits for CDM groups.

In yet another example, there is no mapping relation has been specified, the CDM sequences to be measured have been indicated in L2 MAC CE, the indices of CDM sequences associated with the actually measured ports can also be indicated by the bitmap or combinatorial signaling at L2 MAC CE. There are N CSI-RS ports and L CDM sequences per CDM group, so there are

CDM groups. If the actually configured number is y for CDM sequences, then

gNB configures a bitmap having y “1” out of L bits and “0” elsewhere, or a combinatorial signaling by

bits for CDM sequences.

In such a way, the network device 120 may use downlink Layer2 Medium Access Control Control Element (L2 MAC CE) to let UE knows which CDM groups or CDM sequences will be measured explicitly, without knowing the mapping relation by RRC signaling. Further, the RS port resources to be measured indicated in the CJT configuration may be determined based on the indices of CDM groups, or indices of CDM sequences or both indices of CDM groups and CDM sequences. Further, a TCI may be provided together with the indices of CDM groups, or indices of CDM sequences or both indices of CDM groups and CDM sequences. In this way, it could provide more flexibility on CSI-RS resource configuration.

Similarly, the CJT configuration may be received by means of Medium Access Control Control Element, MAC CE, or Downlink Control Indication, DCI.

In some embodiments, the RS may comprise Channel State Information Reference Signal, CSI-RS, and wherein the RS port resources may comprise port resources of CSI-RS. However, CSI-RS is only given for illustrative purposes and the present disclosure thereto but may be applied to any RS signals with similar issues.

Fig. 4 illustrates a flowchart of a method 400 implemented at a network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 400 will be described from the perspective of the

network device

120 or 130 or 140 or 150 with reference to Fig. 1. It is to be understood that method 400 may further include additional blocks not shown and/or omit some shown blocks, and the scope of the present disclosure is not limited in this regard.

At block 410, the network device 120 transmits a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences. In other words, the network device 120 may indicate information of RS port resources to be measured. The RS port resources may correspond to a part of CDM groups, or CDM sequences, or both of CDM groups and CDM sequences.

In some embodiments, the terminal device 110 may be configured to be communicated with one or more of Transmission Reception Points, TRPs for the CJT, wherein the RS port resources to be measured are at least a part of RS port resources available for multiple TRPs, and wherein the RS port resources available for the multiple TRPs comprise a plurality of RS port resource groups, each RS port resource group corresponds to one of the multiple TRPs and each RS port resource group is associated with one of one or more subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences.

In some embodiments, the information on RS port resources to be measured may comprise any of: one or more indices of RS port resource groups, one or more indices of TRPs, each associated with a RS port resource group, one or more transmission configuration indications, TCI, state identifiers, each being associated with a RS port resource group or TRP.

In some embodiments, the network device 120 may be further caused to indicate a RS port resource association configuration indicating an association between any of the RS port resource groups, the TRPs, or the TCIs and subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences.

In some embodiments, the RS port resources to be measured as indicated in the CJT configuration may be determined based on the information on RS port resources to be measured and the association as indicated in the RS port resource association configuration.

In some embodiments, the network device 120 may be further caused to transmit another CJT configuration indicating indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences, wherein the indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences as indicated in the another CJT configuration are used together with the information on RS port resources to be measured as indicated in the CJT configuration, and the association as indicated in the RS port resource association configuration to determine RS port resources to be actually measured.

In some embodiments, the RS port resource groups may comprise the same number of RS port resources.

In some embodiments, the RS port resource groups may comprise different numbers of RS port resources.

In some embodiments, the information on RS port resources to be measured may comprise indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences.

In some embodiments, the RS port resources to be measured indicated in the CJT configuration may be determined based on the indices of CDM groups, the indices of CDM sequences or both indices of CDM groups and CDM sequences.

In some embodiments, the CJT configuration may be transmitted by means of Medium Access Control Control Element, MAC CE or Downlink Control Indication, DCI.

In some embodiments, the RS port resource association configuration may be transmitted by means of RRC or MAC CE.

In some embodiments, the RS may comprise Channel State Information Reference Signal, CSI-RS, wherein the RS port resources may comprise port resources of CSI-RS.

At block 420, the network device 120 receives a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.

Fig. 5 is a simplified block diagram of a device 500 that is suitable for implementing embodiments of the present disclosure. The device 500 may be provided to implement the communication device, for example the terminal device 110, the

network device

120 or 130 or 140 or 150 as shown in Fig. 1. As shown, the device 500 includes one or more processors 510, and one or more transmitters and/or receivers (TX/RX) 540 coupled to the processor 510. The device 500 may further include one or more memories 520 coupled to the processor 510.

The TX/RX 540 may be for bidirectional communications. The TX/RX 540 has at least one antenna to facilitate communication. The communication interface may represent any interface that is necessary for communication with other network elements.

The processor 510 may be of any type suitable to the local technical network and may include one or more of the following: general purpose computers, special purpose computers, microprocessors, digital signal processors (DSPs) and processors based on multicore processor architecture, as non-limiting examples. The device 500 may have multiple processors, such as an application specific integrated circuit chip that is slaved in time to a clock which synchronizes the main processor.

The memory 520 may include one or more non-volatile memories and one or more volatile memories. Examples of the non-volatile memories include, but are not limited to, a Read Only Memory (ROM) 524, an electrically programmable read only memory (EPROM) , a flash memory, a hard disk, a compact disc (CD) , a digital video disk (DVD) , and other magnetic storage and/or optical storage. Examples of the volatile memories include, but are not limited to, a random access memory (RAM) 522 and other volatile memories that will not last in the power-down duration.

A computer program 530 includes computer executable instructions that are executed by the associated processor 510. The program 530 may be stored in the ROM 524. The processor 6 may perform any suitable actions and processing by loading the program 630 into the RAM 522.

The embodiments of the present disclosure may be implemented by means of the program 530 so that the device 500 may perform any process of the disclosure as discussed with reference to Figs. 2 to 4. The embodiments of the present disclosure may also be implemented by hardware or by a combination of software and hardware.

In some embodiments, the program 530 may be tangibly contained in a computer readable medium which may be included in the device 500 (such as in the memory 520) or other storage devices that are accessible by the device 500. The device 500 may load the program 530 from the computer readable medium to the RAM 522 for execution. The computer readable medium may include any types of tangible non-volatile storage, such as ROM, EPROM, a flash memory, a hard disk, CD, DVD, and the like. Fig. 6 shows an example of the computer readable medium 600 in form of CD or DVD. The computer readable medium has the program 630 stored thereon.

Generally, various embodiments of the present disclosure may be implemented in hardware or special purpose circuits, software, logic or any combination thereof. Some aspects may be implemented in hardware, while other aspects may be implemented in firmware or software which may be executed by a controller, microprocessor or other computing device. While various aspects of embodiments of the present disclosure are illustrated and described as block diagrams, flowcharts, or using some other pictorial representations, it is to be understood that the block, apparatus, system, technique or method described herein may be implemented in, as non-limiting examples, hardware, software, firmware, special purpose circuits or logic, general purpose hardware or controller or other computing devices, or some combination thereof.

The present disclosure also provides at least one computer program product tangibly stored on a non-transitory computer readable storage medium. The computer program product includes computer-executable instructions, such as those included in program modules, being executed in a device on a target real or virtual processor, to carry out the

method

200 or 400 as described above with reference to Figs. 2-4. Generally, program modules include routines, programs, libraries, objects, classes, components, data structures, or the like that perform particular tasks or implement particular abstract data types. The functionality of the program modules may be combined or split between program modules as desired in various embodiments. Machine-executable instructions for program modules may be executed within a local or distributed device. In a distributed device, program modules may be located in both local and remote storage media.

Program code for carrying out methods of the present disclosure may be written in any combination of one or more programming languages. These program codes may be provided to a processor or controller of a general purpose computer, special purpose computer, or other programmable data processing apparatus, such that the program codes, when executed by the processor or controller, cause the functions/operations specified in the flowcharts and/or block diagrams to be implemented. The program code may execute entirely on a machine, partly on the machine, as a stand-alone software package, partly on the machine and partly on a remote machine or entirely on the remote machine or server.

In the context of the present disclosure, the computer program codes or related data may be carried by any suitable carrier to enable the device, apparatus or processor to perform various processes and operations as described above. Examples of the carrier include a signal, computer readable medium, and the like.

The computer readable medium may be a computer readable signal medium or a computer readable storage medium. A computer readable medium may include but not limited to an electronic, magnetic, optical, electromagnetic, infrared, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing. More specific examples of the computer readable storage medium would include an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , an optical fiber, a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing.

Further, while operations are depicted in a particular order, this should not be understood as requiring that such operations be performed in the particular order shown or in sequential order, or that all illustrated operations be performed, to achieve desirable results. In certain circumstances, multitasking and parallel processing may be advantageous. Likewise, while several specific implementation details are contained in the above discussions, these should not be construed as limitations on the scope of the present disclosure, but rather as descriptions of features that may be specific to particular embodiments. Certain features that are described in the context of separate embodiments may also be implemented in combination in a single embodiment. Conversely, various features that are described in the context of a single embodiment may also be implemented in multiple embodiments separately or in any suitable sub-combination.

Although the present disclosure has been described in languages specific to structural features and/or methodological acts, it is to be understood that the present disclosure defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims.

Claims

A terminal device, comprising:

one or more transceivers; and

one or more processors communicatively coupled to the one or more transceivers, and the one or more processors are configured to cause the terminal device to:

receive a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and

measure the associated RS port resources based on the CJT configuration.
The terminal device according to Claim 1, wherein the terminal device is configured to be communicated with one or more of multiple Transmission Reception Points, TRPs for the CJT,

wherein the RS port resources to be measured are at least a part of RS port resources available for multiple TRPs, and

wherein the RS port resources available for the multiple TRPs comprise a plurality of RS port resource groups, each RS port resource group corresponds to one of the multiple TRPs, and each RS port resource group is associated with one of one or more subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences.
The terminal device according to Claim 1 or 2, wherein the information on RS port resources to be measured, comprises any of:

one or more indices of RS port resource groups,

one or more indices of TRPs, each associated with a RS port resource group,

one or more transmission configuration indication, TCI, state identifiers each being associated with a RS port resource group or TRP.
The terminal device according to Claim 3, wherein the terminal device is further caused to:

obtain a RS port resource association configuration indicating an association between any of the RS port resource groups, the TRPs, or the TCIs and subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences.
The terminal device according to Claim 4, wherein the RS port resources to be measured as indicated in the CJT configuration are determined based on the information on RS port resources to be measured and the association as indicated in the RS port resource association configuration.
The terminal device according to Claim 4, wherein the terminal device is further caused to:

receive another CJT configuration indicating indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences that correspond to a subset of RS port resources to be measured as indicated in the CJT configuration,

wherein RS port resources to be measured actually are determined based on the information on RS port resources to be measured as indicated in the CJT configuration, the association as indicated in the RS port resource association configuration and the indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences as indicated in the another CJT configuration, and/or

wherein the another CJT configuration is received by means of Medium Access Control Control Element, MAC CE, or Downlink Control Indication, DCI.
The terminal device according to Claims 2-6, wherein the RS port resource groups comprise the same number of RS port resources.
The terminal device according to Claims 2-6, wherein the RS port resource groups comprise different numbers of RS port resources.
The terminal device according to Claim 1, wherein the information on RS port resources to be measured comprises indices of CDM groups, indices of CDM sequences, or both indices of CDM groups and CDM sequences.
The terminal device according to Claim 9, wherein the RS port resources to be measured indicated in the CJT configuration are determined based on the indices of CDM groups, or indices of CDM sequences or both indices of CDM groups and CDM sequences.
The terminal device any of according to Claims 1 to 10, wherein the CJT configuration is received by means of Medium Access Control Control Element, MAC CE, or Downlink Control Indication, DCI.
The terminal device according to Claims 4 to 8, wherein the RS port resource association configuration is received by means of a Radio Resource Control, RRC, signaling or MAC CE.
The method according to any one of claims 1-12, wherein the RS comprises Channel State Information Reference Signal, CSI-RS, and

wherein the RS port resources comprise port resources of CSI-RS.
A network device, comprising:

one or more transceivers; and

one or more processors communicatively coupled to the one or more transceivers, and the one or more processors are configured to cause the network device to:

transmit a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and

receive a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.
The network device according to Claim 14, wherein a terminal device is configured to be communicated with one or more of multiple Transmission Reception Points, TRPs for the CJT,

wherein the RS port resources to be measured are at least a part of RS port resources available for multiple TRPs, and

wherein the RS port resources available for the multiple TRPs comprise a plurality of RS port resource groups, each RS port resource group corresponds to one of the multiple TRPs and each RS port resource group is associated with one of one or more subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences.
The network device according to Claim 14 or 15, wherein the information on RS port resources to be measured, comprises any of:

one or more indices of RS port resource groups,

one or more indices of TRPs, each associated with a RS port resource group,

one or more transmission configuration indications, TCI, state identifiers, each being associated with a RS port resource group or TRP.
The network device according to Claim 16, wherein the network device is further caused to:

indicate a RS port resource association configuration indicating an association between any of the RS port resource groups, the TRPs, or the TCIs and subsets of CDM groups, CDM sequences or both of CDM groups and CDM sequences.
The network device according to Claim 17, wherein the RS port resources to be measured as indicated in the CJT configuration are determined based on the information on RS port resources to be measured and the association as indicated in the RS port resource association configuration.
The network device according to Claim 17, wherein the network device is further caused to:

transmit another CJT configuration indicating indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences that correspond to a subset of RS port resources to be measured as indicated in the CJT configuration, ,

wherein the indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences as indicated in the another CJT configuration are used together with the information on RS port resources to be measured as indicated in the CJT configuration, and the association as indicated in the RS port resource association configuration to determine RS port resources to be actually measured, and/or

wherein the another CJT configuration is received by means of Medium Access Control Control Element, MAC CE, or Downlink Control Indication, DCI.
The network device according to Claims 15 to 19, wherein the RS port resource groups comprise the same number of RS port resources.
The network device according to Claims 15 to 19, wherein the RS port resource groups comprise different numbers of RS port resources.
The network device according to Claim 14, wherein the information on RS port resources to be measured comprises indices of CDM groups, indices of CDM sequences or both indices of CDM groups and CDM sequences.
The network device according to Claim 22, wherein the RS port resources to be measured indicated in the CJT configuration are determined based on the indices of CDM groups, the indices of CDM sequences or both indices of CDM groups and CDM sequences.
The network device any of according to Claims 14 to 23, wherein the CJT configuration is transmitted by means of Medium Access Control Control Element, MAC CE or Downlink Control Indication, DCI.
The network device according to Claims 17 to 18, wherein the RS port resource association configuration is transmitted by means of RRC or MAC CE.
The method according to any one of claims 17-22, wherein the RS comprises Channel State Information Reference Signal, CSI-RS, wherein the RS port resources comprise port resources of CSI-RS.
A method at a terminal device, comprising:

receiving a coherent joint transmission, CJT, configuration indicating information on reference signal, RS port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and

measuring associated RS port resources based on the CJT configuration.
A method at a network device, comprising:

transmitting a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and

receiving a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.
An apparatus of terminal device, comprising:

means for receiving a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and

means for measuring associated RS port resources based on the CJT configuration.
An apparatus of network device, comprising:

means for transmitting a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and

means for receiving a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.
A terminal device, comprising:

at least one processor; and

at least one memory including computer program codes, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the terminal device to:

receive a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and

measure associated RS port resources based on the CJT configuration.
A network device, comprising:

at least one processor; and

at least one memory including computer program codes, wherein the at least one memory and the computer program codes are configured to, with the at least one processor, cause the network device to:

transmit a coherent joint transmission, CJT, configuration indicating information on reference signal, RS, port resources to be measured, wherein the information on RS port resources to be measured is associated with at least a part of code division multiplexing, CDM, groups, or CDM sequences, or both of CDM groups and CDM sequences; and

receive a measurement report of RS port resources, wherein the measurement report is related to the RS port resources as indicated in the CJT configuration.
A non-transitory computer readable medium comprising program instructions for causing an apparatus to perform at least the method of claim 27 or 28.