WO2025213481A1

WO2025213481A1 - Sounding reference signal configuration

Info

Publication number: WO2025213481A1
Application number: PCT/CN2024/087632
Authority: WO
Inventors: Jun Tan; Youngsoo Yuk; Frederick Vook; Bao Cai LI
Original assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy; Nokia Technologies Oy
Current assignee: Nokia Shanghai Bell Co Ltd; Nokia Solutions and Networks Oy; Nokia Technologies Oy
Priority date: 2024-04-12
Filing date: 2024-04-12
Publication date: 2025-10-16
Anticipated expiration: 2026-10-12

Abstract

Embodiments of the present disclosure relate to a solution for providing a SRS configuration. In one aspect, a terminal device receives a sounding reference signal (SRS) configuration from a network device, and the SRS configuration indicates a SRS selection pattern. Based on the SRS configuration with the SRS selection pattern, the terminal device transmits a SRS to the network device. In this way, SRS resource may be configured to support multiple ports uplink transmission without sacrificing SRS resource. Therefore, overhead of the UL transmission may be reduced.

Description

SOUNDING REFERENCE SIGNAL CONFIGURATION

FIELD

Various example embodiments relate to the field of communication and in particular, to devices, methods, apparatuses and a computer readable storage medium for providing a sounding reference signal (SRS) configuration.

BACKGROUND

A communication network can be seen as a facility that enables communications between two or more communication devices, or provides communication devices access to a data network. A mobile or wireless communication network is one example of a communication network.

Such communication networks operate in accordance with standards, such as those promulgated by Third Generation Partnership Project (3GPP) or European Telecommunications Standards Institute (ETSI) . Examples of such standards include the so-called 5th generation (5G) standard or other standards promulgated by 3GPP.

SUMMARY

In general, example embodiments of the present disclosure provide a solution related to a sounding reference signal (SRS) configuration, especially for SRS multiplexing for 3 transmit antenna (3TX) uplink transmission.

In a first aspect, there is provided a terminal device. The terminal device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to: receive a sounding reference signal (SRS) configuration from a network device, and the SRS configuration indicates a SRS selection pattern; and transmit a SRS to the network device based on the SRS configuration with the SRS selection pattern.

In a second aspect, there is provided a network device. The network device comprises at least one processor and at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to: transmit multiple sounding reference signal (SRS) configurations to multiple terminal devices, and the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices, and receive multiple SRSs from the multiple terminal devices.

In a third aspect, there is provided a method. The method comprises receiving a sounding reference signal (SRS) configuration from a network device, and the SRS configuration indicates a SRS selection pattern, and transmitting a SRS to the network device based on the SRS configuration with the SRS selection pattern.

In a fourth aspect, there is provided a method. The method comprises transmitting multiple sounding reference signal (SRS) configurations to multiple terminal devices, and the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices, and receiving multiple SRSs from the multiple terminal devices.

In a fifth aspect, there is provided an apparatus. The apparatus comprises means for receiving a sounding reference signal (SRS) configuration from a network device, and the SRS configuration indicates a SRS selection pattern, and means for transmitting a SRS to the network device based on the SRS configuration with the SRS selection pattern.

In a sixth aspect, there is provided an apparatus. The apparatus comprises means for transmitting multiple sounding reference signal (SRS) configurations to multiple terminal devices, and the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices, and means for receiving multiple SRSs from the multiple terminal devices.

In a seventh 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 any one of the above third to fourth aspect.

In an eighth aspect, there is provided a computer program comprising instructions, which, when executed by an apparatus, cause the apparatus to perform at least the method according to any one of the above fourth to sixth aspect.

In a ninth aspect, there is provided a terminal device. The terminal device comprises receiving circuitry configured to receive a sounding reference signal (SRS) configuration from a network device, and the SRS configuration indicates a SRS selection pattern, and transmitting circuitry configured to transmit a SRS to the network device based on the SRS configuration with the SRS selection pattern.

In a tenth aspect, there is provided a network device. The network device comprises transmitting circuitry configured to transmit multiple sounding reference signal (SRS) configurations to multiple terminal devices, and the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices, and receiving circuitry configured to receive multiple SRSs from the multiple terminal devices.

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 example embodiments 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, in which:

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

Fig. 2 illustrates an example signaling chart illustrating an example process according to some embodiments of the present disclosure;

Fig. 3 illustrates an example procedure of proposed solution according to some embodiments of the present disclosure;

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

Fig. 5 illustrates a flowchart of a method implemented at a network device according to some embodiments of the present disclosure;

Fig. 6 illustrates a simplified block diagram of an apparatus that is suitable for implementing embodiments of the present disclosure; and

Fig. 7 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

Principles 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 example embodiments of the present disclosure, without suggesting any limitation as to the scope of the disclosure. The example embodiments of the present 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 herein, “at least one of the following: <a list of two or more elements>” and “at least one of <a list of two or more elements>” and similar wording, where the list of two or more elements are joined by “and” or “or” , mean at least any one of the elements, or at least any two or more of the elements, or at least all the elements.

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 first generation (1G) , the second generation (2G) , 2.5G, 2.75G, the third generation (3G) , the fourth generation (4G) , 4.5G, the future fifth generation (5G) communication protocols, and/or any other protocols either currently known or to be developed in the future. 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 example embodiments of 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 new radio (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.

In some communication schemes, uplink (UL) multiple input multiple output (MIMO) usually supports up to 4 uplink transmit (TX) antennas. Both codebook based and non-codebook-based transmission schemes are supported for coherent TX, partial coherent TX, and non-coherent TX. In some other communication schemes, UL MIMO supports up to 8 uplink TX antennas. Codebooks for 8 UL TX antennas were specified for coherent TX, partial coherent TX, and non-coherent TX.

Some communication systems (such as NR) support 1-port, 2-port, 4-port and 8-port physical uplink shared channel (PUSCH) . Nonetheless, mobile UEs are generally equipped with only 1 TX antenna or 2 TX antennas. To enhance the UL performance and anticipating advancements in hardware and design technology, the emergence of UEs equipped with 3 TX antennas is a development in the future. Consequently, it is advantageous to augment communication systems (for example, the NR standards) to support 3-port PUSCH supporting up to 3 layers. Further, it might be desirable that 3TX non-coherent codebook-based transmission may be defined without enhancement on SRS resource, while SRS resource may be re-used to support 3TX operation.

SRS (Sounding Reference Signal) is an essential part to support 3TX non-coherent transmission. The SRS resources may be re-defined with 3 ports, following with the similar SRS design principles used for 2TX, 4TX, and 8TX SRS resources. Re-using the SRS resource would be a possible approach. However, there are issues to completely re-use 4-port SRS resources for 3TX operation.

Instead, 3TX SRS operation can have some minor changes based on the 4TX SRS resources or SRS resources with other number of TX. The “minor” change shall enable 3TX SRS operation with 4TX SRS resources or SRS resources with other number of TX.

In view of the above discussions and analysis, some embodiments of the present disclosure provide a solution related to SRS configurations. In one aspect of this solution, a terminal device receives a sounding reference signal (SRS) configuration from a network device, and the SRS configuration indicates a SRS selection pattern. Based on the SRS configuration with the SRS selection pattern, the terminal device transmits a SRS to the network device. In this way, SRS resource may be configured to support multiple ports uplink transmission without sacrificing SRS resource. Therefore, overhead of the UL transmission may be reduced. Principles and implementations of embodiments of the present disclosure will be described in detail below with reference to Figs. 1-7.

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, network devices.

As illustrated in Fig. 1, the communication network 100 may comprise multiple terminal devices. For example, a terminal device 110-1 (hereinafter may also be referred to as user equipment 110-1 or a UE 110-1) , a terminal device 110-2 (hereinafter may also be referred to as user equipment 110-2 or a UE 110-2) , and a terminal device 110-N (hereinafter may also be referred to as user equipment 110-N or a UE 110-N) . The communication network 100 may further comprise a network device 120. The network device 120 can manage at least one of cells, e.g. cell 101. The terminal device 110-1, the terminal device 110-2, and the terminal device 110-N can communicate with the network device 120 in the coverage of the cell 101. A link from the terminal device 110-1, the terminal device 110-2, or the terminal device 110-N to the network device 120 is referred to as an uplink (UL) , while a link from the network device 120 to the terminal device 110-1, the terminal device 110-2, or the terminal device 110-N is referred to as a downlink (DL) .

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

Communications in the communication system 100 may be implemented according to any proper communication protocol (s) , comprising, but not limited to, cellular communication protocols of the first generation (1G) , the second generation (2G) , the third generation (3G) , the fourth generation (4G) and the fifth generation (5G) and on the like, 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: code division multiple access (CDMA) , frequency division multiple access (FDMA) , time division multiple access (TDMA) , frequency division duplex (FDD) , time division duplex (TDD) , multiple-input multiple-output (MIMO) , orthogonal frequency division multiple (OFDM) , discrete Fourier transform spread OFDM (DFT-s-OFDM) and/or any other technologies currently known or to be developed in the future.

Fig. 2 illustrates a signaling chart illustrating an example process 200 according to some embodiments of the present disclosure. For the purpose of discussion, the process 200 will be described with reference to Fig. 1. The process 200 may involve multiple terminal device (e.g., the terminal device 110-1, the terminal device 110-N) and the network device 120. It is to be understood that the number of terminal devices is only for the purpose of illustration without suggesting any limitations. The process 200 may involve any suitable number of terminal devices adapted for implementing embodiments of the present disclosure. It would be appreciated that although the process 200 has been described in the communication environment 100 of Fig. 1, this process may be likewise applied to other communication scenarios with similar issues.

In the process 200, the network device 120 transmits multiple SRS configurations to multiple terminal devices, and the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices. In other words, the multiple terminal devices may be co-scheduled based on the multiple SRS configurations, and the SRS resource may be multiplexed between the multiple terminal devices. The SRS configuration may be different for different terminal device.

As shown in Fig. 2, the network device 120 transmits 220 a SRS configuration 225 to the terminal device 110-N, and the SRS configuration 225 indicates a SRS selection pattern. Correspondingly, the terminal device 110-N receives 230 the SRS configuration 225 from the network device 120. The network device 120 transmits 235 a SRS configuration 240 to the terminal device 110-1, and the SRS configuration 240 indicates a SRS selection pattern. Correspondingly, the terminal device 110-1 receives 245 SRS configuration 240 from the network device 120. The network device 120 may further transmit SRS configurations indicating SRS selection patterns to other terminal devices.

In some embodiments, the SRS selection pattern may comprise a SRS port selection pattern, or a SRS cyclic-shift selection pattern. The SRS port selection pattern may be used for the one 4-port SRS resource multiplexed between one 3TX UE and one 1TX UE. The SRS cyclic-shift selection pattern may be used for the two 4-port SRS resources or one 8-port SRS resource multiplexed between two 3TX UEs and one 2TX UE or among two 3Tx and two 1Tx UEs. For the SRS cyclic-shift selection pattern, the permutations of the 4-port SRS resources or the 8-port SRS resource may be cyclic shifted.

In an example, the terminal device 110-1 may be a first terminal device with three SRS ports (i.e., the 3TX UE) , and may be co-scheduled with a second terminal device with one SRS port (i.e., the 1TX UE) based on the SRS port selection pattern. In another example, the terminal device 110-1 may be a third terminal device with three SRS ports (i.e., the 3TX UE) , and may be co-scheduled with a first terminal device with three SRS port and a fourth terminal device with two SRS ports (i.e., the 2TX UE) based on the SRS cyclic-shift selection pattern. In yet another example, the terminal device 110-1 may be the third terminal device and may be co-scheduled with the first terminal device and the second terminal device and a fifth terminal device with one SRS port based on the SRS cyclic-shift selection pattern.

In an example, the terminal device 110-N may be a second terminal device with one SRS port, and may be co-scheduled with a first terminal device with three SRS port based on the SRS port selection pattern. In another example, the terminal device 110-N may be a fourth terminal device with two SRS ports, and may be co-scheduled with a first terminal device with three SRS ports and a third terminal device with three SRS ports based on the SRS cyclic-shift selection pattern. In yet another example, the terminal device 110-N may be the second terminal device, and may be co-scheduled with the fifth terminal device with one SRS port and the first terminal device and the third terminal device based on the SRS cyclic-shift selection pattern.

To enable the 3TX operation in SRS resource, the 4TX SRS resources may be utilized instead of defining new 3TX SRS resources. With a 4-port SRS resource, 3 ports may be configured to one 3TX UE, and the remaining 1 port may be re-assigned to other 1TX UE in the network without sacrificing SRS resources. With two 4-port SRS resources or an 8-port SRS resource, six ports may be configured to two 3TX UEs, and the remaining 2 ports may be re-assigned to other 2TX UE or other two 1TX UEs.

In an example, the SRS selection pattern may indicate muting a SRS port of a SRS resource, and the SRS resource has four SRS ports and the SRS resource is assigned to the first terminal device or the third terminal device. For instance, SRS multiplexing may be enabled between one 3TX UE and one 1TX UE by utilizing one 4-port SRS resource. Three ports of the 4-port SRS resource may be configured to the 3TX UE, and the leftover port (e.g., the fourth port) may be considered muted.

In another example, the SRS selection pattern may indicate muting three SRS ports of a SRS resource, and the SRS resource has four SRS ports and the SRS resource is assigned to the second terminal device. For instance, one 4-port SRS resource may be multiplexed between one 3TX UE and one 1TX UE. One port of the 4-port SRS resource may be configured to the 1TX UE, and the leftover three ports may be considered muted.

In yet another example, the SRS selection pattern may indicate muting two SRS ports of two SRS resources, and the two SRS resources have eight SRS ports and the two SRS resources are assigned to the first terminal device and/or the third terminal device. For instance, SRS multiplexing may be enabled between two 3TX UEs and one 2TX UE by utilizing two 4-port SRS resources. Six ports of the two 4-port SRS resources may be configured to the two 3TX UE, and the leftover two ports may be considered muted.

In a further example, the SRS selection pattern may indicate muting six SRS ports of two SRS resources, and the two SRS resources have eight SRS ports and the two SRS resources are assigned to the fourth terminal device. For instance, SRS multiplexing may be enabled between two 3TX UEs and one 2TX UE by utilizing two 4-port SRS resources. Two ports of the two 4-port SRS resources may be configured to the 2TX UE, and the leftover six ports may be considered muted.

In addition, the SRS selection pattern may indicate muting two SRS ports of one SRS resource, and the SRS resource have eight SRS ports and the SRS resource is assigned to the first terminal device and/or the third terminal device. For instance, SRS multiplexing may be enabled between two 3TX UEs and two 1TX UE by utilizing one 8-port SRS resource. Six ports of the 8-port SRS resource may be configured to the two 3TX UEs, and the leftover two ports may be considered muted.

Additionally, the SRS selection pattern may indicate muting six SRS ports of one SRS resource, and the SRS resource have eight SRS ports and the SRS resource is assigned to the fourth terminal device. Additionally, the SRS selection pattern may indicate muting six SRS ports of one SRS resource, and the SRS resource have eight SRS ports and the SRS resource is assigned to the second terminal device and the fifth terminal device. Additionally, the SRS selection pattern may indicate muting seven SRS ports of one SRS resource, and the SRS resource have eight SRS ports and the SRS resource is assigned to the second terminal device or the fifth terminal device.

In some embodiments, the SRS port selection pattern may be associated with a port combination among multiple port combinations. For example, the multiple port combinations may comprise a first port combination in which a first SRS port of the SRS resource, a second SRS port of the SRS resource and a third SRS port of the SRS resource are assigned for the first terminal device, a fourth SRS port of the SRS resource is assigned for the second terminal device. Alternatively or additionally, the multiple port combinations may comprise a second port combination in which the first SRS port, the second SRS port and the fourth SRS port are assigned for the first terminal device, the third SRS port is assigned for the second terminal device.

Alternatively or additionally, the multiple port combinations may comprise a third port combination in which the first SRS port, the third SRS port and the fourth SRS port are assigned for the first terminal device, the second SRS port is assigned for the second terminal device. Alternatively or additionally, the multiple port combinations may comprise a fourth port combination in which the second SRS port, the third SRS port and the fourth SRS port are assigned for the first terminal device, the first SRS port is assigned for the second terminal device. Alternatively or additionally, the multiple port combinations may comprise any combination of two or more of the first port combination, the second port combination, the third port combination, and the fourth port combination.

For example, with one 4-port SRS resource with ports (0, 1, 2, 3) , there are multiple approaches to assign ports to a 3TX UEs as port permutation (i.e., port combination) between the 3TX UE and 1TX UE (denoted as 3+1 case) in Table 1.

Table 1. 4TX port permutation to enable 3TX SRS: 3+1 case

As shown in Table 21 for the 3+1 case, various combinations of SRS cyclic shifts are used to support one 3TX UE and one 1TX UE by using a 4-port SRS resource. For an example, one 3TX UE may use SRS cyclic shift {0, 1, 2} , and remaining SRS cyclic shift {3} can be used by 1TX UE.

In some embodiments, the SRS cyclic-shift selection pattern may be associated with a SRS cyclic-shift combination among multiple SRS cyclic-shift combinations. Additionally or alternatively, the SRS cyclic-shift combination may comprise a first combination of three cyclic shifts from a first SRS resource of the multiple SRS resources which is assigned to the first terminal device, a second combination of three cyclic shifts from the second SRS resource of the multiple SRS resources which is assigned to the third terminal device, a third combination of the remaining cyclic shifts of the multiple SRS resources which is assigned to the fourth terminal device, or any combination of two or more of the above-mentioned items. Additionally, the SRS cyclic-shift combination may further comprise a first combination, a second combination, a third combination, or a fourth combination of one or more cyclic shifts from one SRS resource.

In some other embodiments, the multiple SRS cyclic-shift combinations may comprise a first SRS cyclic-shift combination in which a first SRS cyclic-shift of two SRS resources and a fourth SRS cyclic-shift of the two SRS resources are assigned for the fourth terminal device, a third SRS cyclic-shift of the two SRS resources, a fifth SRS cyclic-shift of the two SRS resources and a seventh SRS cyclic-shift of the two SRS resources are assigned for the first terminal device, and a second SRS cyclic-shift of the two SRS resources, a sixth SRS cyclic-shift of the two SRS resources and an eighth SRS cyclic-shift of the two SRS resources are assigned for the third terminal device.

Alternatively or additionally, the multiple SRS cyclic-shift combinations may comprise a second SRS cyclic-shift combination in which the third SRS cyclic-shift and the sixth SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the fifth SRS cyclic-shift and the seventh SRS cyclic-shift are assigned for the first terminal device, and the second SRS cyclic-shift, the fourth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the third terminal device.

Alternatively or additionally, the multiple SRS cyclic-shift combinations may comprise a third SRS cyclic-shift combination in which the fifth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the third SRS cyclic-shift and the seventh SRS cyclic-shift are assigned for the first terminal device, and the second SRS cyclic-shift, the fourth SRS cyclic-shift and the sixth SRS cyclic-shift are assigned for the third terminal device.

Alternatively or additionally, the multiple SRS cyclic-shift combinations may comprise a fourth SRS cyclic-shift combination in which the seventh SRS cyclic-shift and the second SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the third SRS cyclic-shift and the fifth SRS cyclic-shift are assigned for the first terminal device, and the fourth SRS cyclic-shift, the sixth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the third terminal device.

Alternatively or additionally, the multiple SRS cyclic-shift combinations may comprise any combination of two or more of the first SRS cyclic-shift combination, the second SRS cyclic-shift combination, the third SRS cyclic-shift combination, and the fourth SRS cyclic-shift combination.

For example, the 3TX UE can be multiplexing with 2TX UE where two 3-port SRS resources and one 2-port SRS resource are supported with various SRS port “muting” options (i.e., 3+3+2 case) . These are examples of the 3+3+2 case shown in Table 2, based on 4-port SRS resources, the SRS COMB is equal to 2 and maximum cyclic shifts is equal to 8. The 4-port SRS resource has cyclic shift (CS) as: {0, 2, 4, 6} , {1, 3, 5, 7} for COMB is equal to 2.

Table 2. 4-port permutation for SRS port multiplexing: 3+3+2 case

As shown in Table 2 for the 3+3+2 case, various combinations of SRS cyclic shifts are used to support one 2TX UE and two 3TX UEs by using two 4-port SRS resource. For an example, one 3-port UE1 may use SRS cyclic shift {2, 4, 6} , another 3-port UE2 can use SRS cyclic shift {1, 5, 7} , and remaining SRS cyclic shift {0, 3} can be used by 2-port UE3. These SRS cyclic shifts are part of two 4-port SRS resources with COMB=2. Therefore, these cyclic shift patterns can enable SRS port multiplexing among two 3-port UEs and one 2-port UEs, by utilizing two 4-port SRS resources.

In addition, the SRS configuration may be carried by a RRC message, a MAC CE, or downlink control information (DCI) . For example, a gNB may determine a proper TX port permutation for a UE with SRS configuration through signaling. The signaling can be either based on the RRC message, MAC CE or through the DCI. The various port permutations can mitigate possible SRS inter-cell interference. The port permutation assigned to a UE can be static (e.g., RRC) or dynamically assigned (e.g., DCI or MAC CE) . With a DCI assignment, for the 3+1 case, an indicator of the TX port permutation would be included with the DCI. With a DCI assignment, for the 3+3+2 case, an indicator of the TX port permutation and SRS cyclic shift permutation would be included with the DCI.

Additionally, the SRS configuration may further comprise an indication of switching between multiple port combinations for the terminal device. For the 3+1 case, the UE’s port combination may be switched between the four choices listed in Table 1 in some known pre-determined way for different SRS transmissions. For example, the first transmission from a UE could be configured to use TX port permutation 1 (i.e., first port combination) ; the second transmission from a UE could be configured to use TX port permutation 2 (i.e., second port combination) , etc. In this way, another level of randomization is provided to help mitigate SRS inter-cell interference.

For the 3+3+2 case, the UE’s SRS cyclic shift combination may be switched between the four choices listed in Table 2 in some known pre-determined way for different SRS transmissions. For example, the first transmission from a UE could be configured to use permutation 1 (i.e., first SRS cyclic-shift combination) ; the second transmission from a UE could be configured to use permutation 2 (i.e., second SRS cyclic-shift combination) , etc. In this way, another level of randomization is provided to help mitigate SRS inter-cell interference.

In some embodiments, the terminal device 110-N may be the second terminal device with one SRS port or the fourth terminal device with two SRS ports, the terminal device 110-N may further transmit 205 a capability indicator 210 to the network device 120. The capability indicator 210 indicates the terminal device 110-N is capable of being co-scheduled with a terminal device with three SRS ports. Correspondingly, the network device 120 may receive 215 the capability indicator 210 from the terminal device 110-N.

For example, if a 3TX UE and a 1TX UE are co-scheduled to transmit the 4TX SRS resource together., the 1TX UE shall indicate in its capability. A UE capability indicator may be defined to indicate that the 1TX UE is capable of being co-scheduled with the 3TX UE for the combined 4TX SRS transmission. Similarly, if two 3TX UEs and a 2TX UE are co-scheduled to transmit with the two 4TX SRS resources together, the 2TX UE shall indicate in its capability. A UE capability indicator may be defined to indicate that the 2TX UE is capable of being co-scheduled with the 3TX UE for the combined 4TX SRS transmission.

Continuing with reference to Fig. 2, based on the SRS configuration 225 with the SRS selection pattern, the terminal device 110-N transmits 250 a SRS 255 to the network device 120. Based on the SRS configuration 240 with the SRS selection pattern, the terminal device 110-1 transmits 265 a SRS 270 to the network device 120.

Correspondingly, the network device 120 receives multiple SRSs from the multiple terminal devices. As shown in Fig. 2, the network device 120 receives 260 the SRS 255 from the terminal device 110-N. The network device 120 receives 275 the SRS 270 from the terminal device 110-1.

In view of the process 200, SRS multiplexing may be enabled between one 3TX UE and one 1TX UE by utilizing one 4-port SRS resource. SRS multiplexing may be enabled between two 3TX UEs and one 2TX UE by utilizing two 4-port SRS resources or one 8-port SRS resource. SRS multiplexing may be further enabled between two 3TX UEs and two 1TX UEs by utilizing two 4-port SRS resources or one 8-port SRS resource. Various port permutations are assigned to UEs to mitigate SRS inter-cell interference. Such assignment may be based on gNB signaling, via RRC, MAC CE or DCI.

Fig. 3 illustrates an example procedure of proposed solution according to some embodiments of the present disclosure. The procedure 300 implemented at a network device 120. It is understood that the process 300 can be considered as a more specific example of the process 200 in Fig. 2.

As shown in Fig. 3, at 310, the network device 120 may determine whether a capability indicator was received from a 1TX UE, or a 2TX UE. The capability indicator indicates that the 1TX UE or the 2TX UE is capable of being co-scheduled with the 3TX UE for the combined 4TX SRS transmission.

At 320, if the network device 120 has received the capability indicator from a 1TX UE or a 2TX UE, the network device 120 transmits multiple SRS configurations indicating multiple SRS selection patterns to multiple UEs. The multiple UEs comprises at least one 3 TX UE, and at least one of a 1TX UE or a 2TX UE. At 330, the network device 120 receives multiple SRSs from the multiple UEs.

At 340, if the network device 120 doesn’t receive the capability indicator from a 1TX UE, or a 2TX UE, the 1TX UE or the 2TX UE can’t be co-scheduled with the 3TX UE. The network device 120 transmits a SRS configuration without a SRS selection pattern to the 1TX UE or the 2TX UE. The SRS configuration of 340 is based on legacy SRS configuration. At 350, the network device 120 receives a SRS from the 1TX UE or the 2TX UE.

Fig. 4 shows a flowchart of an example method 400 implemented at a terminal 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 terminal device 110-1, the terminal device 110-2, or the terminal device 110-N with reference to Fig. 1.

At block 410, the terminal device receives, from a network device, a sounding reference signal (SRS) configuration, wherein the SRS configuration indicates a SRS selection pattern. At block 420, the terminal device transmits, to the network device, a SRS based on the SRS configuration with the SRS selection pattern.

In some embodiments, the SRS selection pattern may comprise one of a SRS port selection pattern, or a SRS cyclic-shift selection pattern. In some embodiments, the terminal device may be a first terminal device with three SRS ports, and may be co-scheduled with a second terminal device with one SRS port based on the SRS port selection pattern; the terminal device may be a second terminal device with one SRS port, and may be co-scheduled with a first terminal device with three SRS port based on the SRS port selection pattern; the terminal device 1 may be a third terminal device with three SRS ports, and may be co-scheduled with a first terminal device with three SRS port and a fourth terminal device with two SRS ports based on the SRS cyclic-shift selection pattern; or the terminal device may be a fourth terminal device with two SRS ports, and may be co-scheduled with a first terminal device with three SRS port and a third terminal device with three SRS ports based on the SRS cyclic-shift selection pattern.

In some embodiments, the SRS configuration further may comprise an indication of switching between multiple port combinations for the terminal device. In some embodiments, the SRS selection pattern may comprise at least one of the following: muting a SRS port of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the first terminal device or the third terminal device; muting three SRS ports of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the second terminal device; muting two SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the first terminal device and/or the third terminal device; or muting six SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the fourth terminal device.

In some embodiments, the SRS port selection pattern may be associated with a port combination among multiple port combinations. In some embodiments, the SRS cyclic-shift selection pattern may be associated with a SRS cyclic-shift combination among multiple SRS cyclic-shift combinations.

In some embodiments, the multiple port combinations may comprise at least one of the following with a SRS resource: a first port combination in which a first SRS port of the SRS resource, a second SRS port of the SRS resource and a third SRS port of the SRS resource are assigned for the first terminal device, a fourth SRS port of the SRS resource is assigned for the second terminal device; a second port combination in which the first SRS port, the second SRS port and the fourth SRS port are assigned for the first terminal device, the third SRS port is assigned for the second terminal device; a third port combination in which the first SRS port, the third SRS port and the fourth SRS port are assigned for the first terminal device, the second SRS port is assigned for the second terminal device; or a fourth port combination in which the second SRS port, the third SRS port and the fourth SRS port are assigned for the first terminal device, the first SRS port is assigned for the second terminal device.

In some embodiments, the SRS cyclic-shift combination comprises at least one of the following with multiple SRS resources: a first combination of three cyclic shifts from a first SRS resource of the multiple SRS resources which is assigned to the first terminal device, a second combination of three cyclic shifts from the second SRS resource of the multiple SRS resources which is assigned to the third terminal device, or a third combination of the remaining cyclic shifts of the multiple SRS resources which is assigned to the fourth terminal device.

In some embodiments, the multiple SRS cyclic-shift combinations may comprise at least one of the following with two SRS resources: a first SRS cyclic-shift combination in which a first SRS cyclic-shift of two SRS resource and a fourth SRS cyclic-shift of the two SRS resources are assigned for the fourth terminal device, a third SRS cyclic-shift of the two SRS resources, a fifth SRS cyclic-shift of the two SRS resources and a seventh SRS cyclic-shift of the two SRS resources are assigned for the first terminal device, and a second SRS cyclic-shift of the two SRS resources, a sixth SRS cyclic-shift of the two SRS resources and an eighth SRS cyclic-shift of the two SRS resources are assigned for the third terminal device; a second SRS cyclic-shift combination in which the third SRS cyclic-shift and the sixth SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the fifth SRS cyclic-shift and the seventh SRS cyclic-shift are assigned for the first terminal device, and the second SRS cyclic-shift, the fourth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the third terminal device; a third SRS cyclic-shift combination in which the fifth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the third SRS cyclic-shift and the seventh SRS cyclic-shift are assigned for the first terminal device, and the second SRS cyclic-shift, the fourth SRS cyclic-shift and the sixth SRS cyclic-shift are assigned for the third terminal device; or a fourth SRS cyclic-shift combination in which the seventh SRS cyclic-shift and the second SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the third SRS cyclic-shift and the fifth SRS cyclic-shift are assigned for the first terminal device, and the fourth SRS cyclic-shift, the sixth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the third terminal device.

In some embodiments, the terminal device may be the second terminal device or the fourth terminal device, and the terminal device may further transmit, to the network device, a capability indicator indicating that the terminal device is capable of being co-scheduled with a terminal device with three SRS ports.

In some embodiments, the SRS configuration may be carried by one of a radio resource control (RRC) message, a medium access control (MAC) control element (MAC CE) or downlink control information (DCI) .

Fig. 5 shows a flowchart of an example method 500 implemented at a network device in accordance with some embodiments of the present disclosure. For the purpose of discussion, the method 500 will be described from the perspective of the network device 120 with reference to Fig. 1.

At block 510, the network device 120 transmits, to multiple terminal devices, multiple sounding reference signal (SRS) configurations, wherein the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices. At block 620, the network device 120 receives, from the multiple terminal devices, multiple SRSs.

In some embodiments, the SRS selection pattern may comprise one of a SRS port selection pattern, or a SRS cyclic-shift selection pattern. In some embodiments, the multiple terminal devices may comprise at least one of: a first terminal device with three SRS ports, and may be co-scheduled with a second terminal device with one SRS port based on the SRS port selection pattern; a second terminal device with one SRS port, and may be co-scheduled with a first terminal device with three SRS port based on the SRS port selection pattern; a third terminal device with three SRS ports, and may be co-scheduled with a first terminal device with three SRS port and a fourth terminal device with two SRS ports based on the SRS cyclic-shift selection pattern; or a fourth terminal device with two SRS ports, and may be co-scheduled with a first terminal device with three SRS port and a third terminal device with three SRS ports based on the SRS cyclic-shift selection pattern.

In some embodiments, the SRS configuration may further comprise an indication of switching between multiple port combinations for the multiple terminal devices. In some embodiments, the SRS selection pattern may comprise at least one of the following: muting a SRS port of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the first terminal device or the third terminal device; muting three SRS ports of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the second terminal device; muting two SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the first terminal device and/or the third terminal device; or muting six SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the fourth terminal device.

In some embodiments, the SRS port selection pattern may be associated with a port combination among multiple port combinations; or the SRS cyclic-shift selection pattern may be associated with a SRS cyclic-shift combination among multiple SRS cyclic-shift combinations.

In some embodiments, the SRS cyclic-shift combination may comprise at least one of the following with multiple SRS resources: a first combination of three cyclic shifts from a first SRS resource of the multiple SRS resources which is assigned to the first terminal device, a second combination of three cyclic shifts from the second SRS resource of the multiple SRS resources which is assigned to the third terminal device, or a third combination of the remaining cyclic shifts of the multiple SRS resources which is assigned to the fourth terminal device.

In some embodiments, the network device 120 may further receive, from the second terminal device or the fourth terminal device, a capability indicator indicating that the second terminal device or the fourth terminal device is capable of being co-scheduled with a terminal device with three SRS ports.

In some embodiments, an apparatus capable of performing any of the method 400 (for example, the terminal device 110-1, 110-2, or 110-N) is provided. The apparatus may comprise means for performing the respective steps of the method 400. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for receiving, from a network device, a sounding reference signal (SRS) configuration, wherein the SRS configuration indicates a SRS selection pattern; and means for transmitting, to the network device, a SRS based on the SRS configuration with the SRS selection pattern.

In some embodiments, the SRS selection pattern may comprise one of a SRS port selection pattern, or a SRS cyclic-shift selection pattern.

In some embodiments, the terminal device may be a first terminal device with three SRS ports, and may be co-scheduled with a second terminal device with one SRS port based on the SRS port selection pattern; the terminal device may be a second terminal device with one SRS port, and may be co-scheduled with a first terminal device with three SRS port based on the SRS port selection pattern; the terminal device 1may be a third terminal device with three SRS ports, and may be co-scheduled with a first terminal device with three SRS port and a fourth terminal device with two SRS ports based on the SRS cyclic-shift selection pattern; or the terminal device may be a fourth terminal device with two SRS ports, and may be co-scheduled with a first terminal device with three SRS port and a third terminal device with three SRS ports based on the SRS cyclic-shift selection pattern.

In some embodiments, the SRS configuration further may comprise an indication of switching between multiple port combinations for the terminal device.

In some embodiments, the SRS selection pattern may comprise at least one of the following: muting a SRS port of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the first terminal device or the third terminal device; muting three SRS ports of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the second terminal device; muting two SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the first terminal device and/or the third terminal device; or muting six SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the fourth terminal device.

In some embodiments, the terminal device may be the second terminal device or the fourth terminal device, the apparatus may further comprise means for transmitting, to the network device, a capability indicator indicating that the terminal device is capable of being co-scheduled with a terminal device with three SRS ports.

In some embodiments, the apparatus further comprises means for performing other steps in some embodiments of the method 400. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the apparatus.

In some embodiments, an apparatus capable of performing any of the method 500 (for example, the network device 120) is provided. The apparatus may comprise means for performing the respective steps of the method 500. The means may be implemented in any suitable form. For example, the means may be implemented in a circuitry or software module.

In some embodiments, the apparatus comprises means for transmitting, to multiple terminal devices, multiple sounding reference signal (SRS) configurations, wherein the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices; and means for receiving, from the multiple terminal devices, multiple SRSs.

In some embodiments, the apparatus may comprise means for receiving, from the second terminal device or the fourth terminal device, a capability indicator indicating that the second terminal device or the fourth terminal device is capable of being co-scheduled with a terminal device with three SRS ports. In some embodiments, the SRS configuration may be carried by one of a radio resource control (RRC) message, a medium access control (MAC) control element (MAC CE) or downlink control information (DCI) .

In some embodiments, the device further comprises means for performing other steps in some embodiments of the method 500. In some embodiments, the means comprises at least one processor and at least one memory including computer program code, the at least one memory and computer program code configured to, with the at least one processor, cause the performance of the device.

FIG. 6 is a simplified block diagram of a device 600 that is suitable for implementing embodiments of the present disclosure. The device 600 may be provided to implement the communication device, for example the terminal device 110-1, the terminal device 110-2, the terminal device 110-N, or the network device 120 as shown in Fig. 1. As shown, the device 600 includes one or more processors 610, one or more memories 620 coupled to the processor 610, and one or more communication modules 640 coupled to the processor 610.

The communication modules 640 is for bidirectional communications. The communication modules 640 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 610 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 600 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 620 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) 624, 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) 622 and other volatile memories that will not last in the power-down duration.

A computer program 630 includes computer executable instructions that are executed by the associated processor 610. The program 630 may be stored in the ROM 624. The processor 610 may perform any suitable actions and processing by loading the program 630 into the RAM 622.

The embodiments of the present disclosure may be implemented by means of the program 630 so that the device 600 may perform any process of example embodiments of the disclosure as discussed with reference to Figs. 2 to 6. 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 630 may be tangibly contained in a computer readable medium which may be included in the device 600 (such as in the memory 620) or other storage devices that are accessible by the device 600. The device 600 may load the program 630 from the computer readable medium to the RAM 622 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. 7 shows an example of the computer readable medium 700 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.

Example embodiments of 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 methods 400, and 500 as described above with reference to Figs. 4-5. 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 example embodiments 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. The term “non-transitory, ” as used herein, is a limitation of the medium itself (i.e., tangible, not a signal) as opposed to a limitation on data storage persistency (e.g., RAM vs. ROM) .

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 example embodiments of the present disclosure have been described in languages specific to structural features and/or methodological acts, it is to be understood that the example embodiments of 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:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the terminal device at least to:

receive, from a network device, a sounding reference signal (SRS) configuration, wherein the SRS configuration indicates a SRS selection pattern; and

transmit, to the network device, a SRS based on the SRS configuration with the SRS selection pattern.
The terminal device of claim 1, wherein the SRS selection pattern comprises one of a SRS port selection pattern, or a SRS cyclic-shift selection pattern.
The terminal device of claim 1 or 2, wherein one of the following:

the terminal device is a first terminal device with three SRS ports, and is co-scheduled with a second terminal device with one SRS port based on the SRS port selection pattern;

the terminal device is a second terminal device with one SRS port, and is co-scheduled with a first terminal device with three SRS port based on the SRS port selection pattern;

the terminal device is a third terminal device with three SRS ports, and is co-scheduled with a first terminal device with three SRS port and a fourth terminal device with two SRS ports based on the SRS cyclic-shift selection pattern; or

the terminal device is a fourth terminal device with two SRS ports, and is co-scheduled with a first terminal device with three SRS port and a third terminal device with three SRS ports based on the SRS cyclic-shift selection pattern.
The terminal device of any of claims 1-3, wherein the SRS configuration further comprises an indication of switching between multiple port combinations for the terminal device.
The terminal device of any of claims 1-4, wherein the SRS selection pattern indicates at least one of the following:

muting a SRS port of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the first terminal device or the third terminal device;

muting three SRS ports of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the second terminal device;

muting two SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the first terminal device and/or the third terminal device; or

muting six SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the fourth terminal device.
The terminal device of any of claims 2-5, wherein at least one of the following:

the SRS port selection pattern is associated with a port combination among multiple port combinations; or

the SRS cyclic-shift selection pattern is associated with a SRS cyclic-shift combination among multiple SRS cyclic-shift combinations.
The terminal device of claim 6, wherein the multiple port combinations comprise at least one of the following with a SRS resource:

a first port combination in which a first SRS port of the SRS resource, a second SRS port of the SRS resource and a third SRS port of the SRS resource are assigned for the first terminal device, a fourth SRS port of the SRS resource is assigned for the second terminal device;

a second port combination in which the first SRS port, the second SRS port and the fourth SRS port are assigned for the first terminal device, the third SRS port is assigned for the second terminal device;

a third port combination in which the first SRS port, the third SRS port and the fourth SRS port are assigned for the first terminal device, the second SRS port is assigned for the second terminal device; or

a fourth port combination in which the second SRS port, the third SRS port and the fourth SRS port are assigned for the first terminal device, the first SRS port is assigned for the second terminal device.
The terminal device of claim 6, wherein the SRS cyclic-shift combination comprises at least one of the following with multiple SRS resources:

a first combination of three cyclic shifts from a first SRS resource of the multiple SRS resources which is assigned to the first terminal device,

a second combination of three cyclic shifts from the second SRS resource of the multiple SRS resources which is assigned to the third terminal device, or

a third combination of the remaining cyclic shifts of the multiple SRS resources which is assigned to the fourth terminal device.
The terminal device of claim 6 or 8, wherein the multiple SRS cyclic-shift combinations comprise at least one of the following with two SRS resources:

a first SRS cyclic-shift combination in which a first SRS cyclic-shift of two SRS resources and a fourth SRS cyclic-shift of the two SRS resources are assigned for the fourth terminal device, a third SRS cyclic-shift of the two SRS resources, a fifth SRS cyclic-shift of the two SRS resources and a seventh SRS cyclic-shift of the two SRS resources are assigned for the first terminal device, and a second SRS cyclic-shift of the two SRS resources, a sixth SRS cyclic-shift of the two SRS resources and an eighth SRS cyclic-shift of the two SRS resources are assigned for the third terminal device;

a second SRS cyclic-shift combination in which the third SRS cyclic-shift and the sixth SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the fifth SRS cyclic-shift and the seventh SRS cyclic-shift are assigned for the first terminal device, and the second SRS cyclic-shift, the fourth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the third terminal device;

a third SRS cyclic-shift combination in which the fifth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the third SRS cyclic-shift and the seventh SRS cyclic-shift are assigned for the first terminal device, and the second SRS cyclic-shift, the fourth SRS cyclic-shift and the sixth SRS cyclic-shift are assigned for the third terminal device; or

a fourth SRS cyclic-shift combination in which the seventh SRS cyclic-shift and the second SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the third SRS cyclic-shift and the fifth SRS cyclic-shift are assigned for the first terminal device, and the fourth SRS cyclic-shift, the sixth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the third terminal device.
The terminal device of any of claims 3-9, wherein the terminal device is the second terminal device or the fourth terminal device, and the terminal device is further caused to:

transmit, to the network device, a capability indicator indicating that the terminal device is capable of being co-scheduled with a terminal device with three SRS ports.
A network device comprising:

at least one processor; and

at least one memory storing instructions that, when executed by the at least one processor, cause the network device at least to:

transmit, to multiple terminal devices, multiple sounding reference signal (SRS) configurations, wherein the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices; and

receive, from the multiple terminal devices, multiple SRSs.
The network device of claim 11, wherein the SRS selection pattern comprises one of a SRS port selection pattern, or a SRS cyclic-shift selection pattern.
The network device of claim 11 or 12, wherein the multiple terminal devices comprise at least one of:

a first terminal device with three SRS ports, and is co-scheduled with a second terminal device with one SRS port based on the SRS port selection pattern;

a second terminal device with one SRS port, and is co-scheduled with a first terminal device with three SRS port based on the SRS port selection pattern;

a third terminal device with three SRS ports, and is co-scheduled with a first terminal device with three SRS port and a fourth terminal device with two SRS ports based on the SRS cyclic-shift selection pattern; or

a fourth terminal device with two SRS ports, and is co-scheduled with a first terminal device with three SRS port and a third terminal device with three SRS ports based on the SRS cyclic-shift selection pattern.
The network device of any of claims 11-13, wherein the SRS configuration further comprises an indication of switching between multiple port combinations for the multiple terminal devices.
The network device of any of claims 11-14, wherein the SRS selection pattern comprises at least one of the following:

muting a SRS port of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the first terminal device or the third terminal device;

muting three SRS ports of a SRS resource, wherein the SRS resource has four SRS ports and the SRS resource is assigned to the second terminal device;

muting two SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the first terminal device and/or the third terminal device; or

muting six SRS ports of two SRS resources, wherein the two SRS resources have eight SRS ports and the two SRS resources are assigned to the fourth terminal device.
The network device of any of claims 12-15, wherein at least one of the following:

the SRS port selection pattern is associated with a port combination among multiple port combinations; or

the SRS cyclic-shift selection pattern is associated with a SRS cyclic-shift combination among multiple SRS cyclic-shift combinations.
The network device of claim 16, wherein the multiple port combinations comprise at least one of the following with a SRS resource:

a first port combination in which a first SRS port of the SRS resource, a second SRS port of the SRS resource and a third SRS port of the SRS resource are assigned for the first terminal device, a fourth SRS port of the SRS resource is assigned for the second terminal device;

a second port combination in which the first SRS port, the second SRS port and the fourth SRS port are assigned for the first terminal device, the third SRS port is assigned for the second terminal device;

a third port combination in which the first SRS port, the third SRS port and the fourth SRS port are assigned for the first terminal device, the second SRS port is assigned for the second terminal device; or

a fourth port combination in which the second SRS port, the third SRS port and the fourth SRS port are assigned for the first terminal device, the first SRS port is assigned for the second terminal device.
The terminal device of claim 16, wherein the SRS cyclic-shift combination comprises at least one of the following with multiple SRS resources:

a first combination of three cyclic shifts from a first SRS resource of the multiple SRS resources which is assigned to the first terminal device,

a second combination of three cyclic shifts from the second SRS resource of the multiple SRS resources which is assigned to the third terminal device,

a third combination of the remaining cyclic shifts of the multiple SRS resources which is assigned to the fourth terminal device.
The network device of claim 15 or 18, wherein the multiple SRS cyclic-shift combinations comprise at least one of the following with two SRS resources:

a first SRS cyclic-shift combination in which a first SRS cyclic-shift of two SRS resources and a fourth SRS cyclic-shift of the two SRS resources are assigned for the fourth terminal device, a third SRS cyclic-shift of the two SRS resources, a fifth SRS cyclic-shift of the two SRS resources and a seventh SRS cyclic-shift of the two SRS resources are assigned for the first terminal device, and a second SRS cyclic-shift of the two SRS resources, a sixth SRS cyclic-shift of the two SRS resources and an eighth SRS cyclic-shift of the two SRS resources are assigned for the third terminal device;

a second SRS cyclic-shift combination in which the third SRS cyclic-shift and the sixth SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the fifth SRS cyclic-shift and the seventh SRS cyclic-shift are assigned for the first terminal device, and the second SRS cyclic-shift, the fourth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the third terminal device;

a third SRS cyclic-shift combination in which the fifth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the third SRS cyclic-shift and the seventh SRS cyclic-shift are assigned for the first terminal device, and the second SRS cyclic-shift, the fourth SRS cyclic-shift and the sixth SRS cyclic-shift are assigned for the third terminal device; or

a fourth SRS cyclic-shift combination in which the seventh SRS cyclic-shift and the second SRS cyclic-shift are assigned for the fourth terminal device, the first SRS cyclic-shift, the third SRS cyclic-shift and the fifth SRS cyclic-shift are assigned for the first terminal device, and the fourth SRS cyclic-shift, the sixth SRS cyclic-shift and the eighth SRS cyclic-shift are assigned for the third terminal device.
The network device of any of claims 13-19, wherein the network device is further caused to:

receive, from the second terminal device or the fourth terminal device, a capability indicator indicating that the second terminal device or the fourth terminal device is capable of being co-scheduled with a terminal device with three SRS ports.
A method comprising:

receiving, at a terminal device from a network device, a sounding reference signal (SRS) configuration, wherein the SRS configuration indicates a SRS selection pattern; and

transmitting, to the network device, a SRS based on the SRS configuration with the SRS selection pattern.
A method comprising:

transmitting, at a network device to multiple terminal devices, multiple sounding reference signal (SRS) configurations, wherein the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices; and

receiving, from the multiple terminal devices, multiple SRSs.
An apparatus comprising:

means for receiving, at a terminal device from a network device, a sounding reference signal (SRS) configuration, wherein the SRS configuration indicates a SRS selection pattern; and

means for transmitting, to the network device, a SRS based on the SRS configuration with the SRS selection pattern.
An apparatus comprising:

means for transmitting, at a network device to multiple terminal devices, multiple sounding reference signal (SRS) configurations, wherein the multiple SRS configurations indicate multiple SRS selection patterns for SRS multiplexing among the multiple terminal devices; and

means for receiving, from the multiple terminal devices, multiple SRSs.
A non-transitory computer readable medium comprising program instructions that, when executed by an apparatus, cause the apparatus to perform at least the method of claim 21 or 22.