WO2021151394A1

WO2021151394A1 - Method, terminal device and network device for sounding reference signal transmission

Info

Publication number: WO2021151394A1
Application number: PCT/CN2021/074437
Authority: WO
Inventors: Li Guo
Original assignee: Guangdong Oppo Mobile Telecommunications Corp., Ltd.
Priority date: 2020-01-31
Filing date: 2021-01-29
Publication date: 2021-08-05

Abstract

A method for transmitting a sounding reference signal (SRS) resource, comprising: receiving, by a terminal device, SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information; determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission; and transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour.

Description

METHOD, TERMINAL DEVICE AND NETWORK DEVICE FOR SOUNDING REFERENCE SIGNAL TRANSMISSION

CROSS-REFERENCE TO RELATED APPLICATION

This application claims priority to and the benefit of United States Patent Application No. 62/968,921, filed on January 31, 2020, the entire content of which is incorporated herein by reference.

TECHNICAL FIELD

The present application relates to the field of communications, and more particularly to a method, terminal device, and network device for transmitting a sounding reference signal (SRS) resource.

BACKGROUND

The 5G (fifth-generation) wireless systems can include a multi-beam based systems in Frequency Range (FR2) , where multiplex transmit (Tx) and receive (Rx) analog beams are employed by a network device (e.g. a base station such as a gNB) and/or a terminal device (e.g. a user equipment (UE) ) to combat the large path loss in a high frequency band. In a high frequency band system, for example mmWave systems, the network device and the terminal device are deployed with a large number of antennas so that large gain beamforming can be used to defeat the large path loss and signal blockage. Due to the hardware limitation and cost, the network device and the terminal device might only be equipped with a limited number of transmission and reception units (TXRUs) . Therefore, hybrid beamforming mechanisms can be utilized in both the network device and terminal device. To get the best link quality between the network device and the terminal device, the network device and the terminal device need to align the analog beam directions for a particular downlink or uplink transmission. For downlink transmission, they need find the best pair of network device Tx beam and terminal device Rx beam while for uplink transmission, they need to find the best pair of terminal device Tx beam and network device Rx beam.

For the communication between one terminal device and a network device, the terminal device and the network device need to determine which Tx and Rx beam are going to be used. When one terminal device moves, the beams used by the network device and the terminal device for communication might change.

In the third generation partnership project (3GPP) 5G NR release 15 specifications, the following functions are defined to support such multi-beam-based operation: beam measurement and reporting, beam indication and beam switch.

In the current design of 5G NR release 15, the network device may configure a sounding reference signal (SRS) resource set comprising at least one SRS resource to the terminal device, using the radio resource control (RRC) parameter SRS-ResourceSet in the SRS-Config information element (IE) . The usage of that SRS resource set can be set to be ‘codebook’ or ‘non-codebook’ . One or more SRS resources can be configured in the SRS resource set, using an SRS-Resource parameter. The SRS resource is configured with SRS-SpatialRelationInfo, which contains a downlink or uplink reference signal providing Tx beam information. In addition, the SRS resource is configured with a resourceType providing a time domain behaviour for the SRS resource. The terminal device can then transmit SRS resources from the SRS resource set according to this configuration.

In addition, these SRS resources can be used in the scheduling of physical uplink shared channel (PUSCH) transmissions. To schedule a PUSCH transmission, the network device can send one downlink control information (DCI) format to the terminal device and in the DCI format, a bit-field SRS resource indicator (SRI) is used to indicate one or more SRS resources from that SRS resource set dedicated for PUSCH transmission. For the terminal device to determine the Tx beam for that PUSCH, the terminal device may derive it based on the Tx beam information configured to the SRS resource dedicated for PUSCH transmission. If the network device needs to change the Tx beam for PUSCH transmission, the network device would have to use higher layer signalling (i.e. higher than the physical layer) to change the Tx beam configuration of those SRS resources dedicated for PUSCH transmission. The Tx beam configured to the SRS resources dedicated for PUSCH transmission can be an SRS resource, a channel state information reference signal (CSI-RS) resource or a signal/physical broadcast channel (SS/PBCH) block.

Two transmission schemes are supported for PUSCH: codebook based transmission and non-codebook based transmission. The transmission scheme is configured through a radio resource control (RRC) parameter.

For codebook-based PUSCH transmission, the terminal device is configured with an SRS resource set with usage set to ‘codebook’ , which is dedicated for codebook-based transmission. That set can contain one or two SRS resources. Each SRS resource is configured with a parameter SpatialRelationInfo that contains a reference signal ID (e.g. CSI-RS or SS/PBCH or SRS) to provide a reference for spatial relation information. For one PUSCH transmission, the network device indicates one SRS resource from that set to the terminal device and the terminal device derives a Tx beam for the PUSCH based on the SpatialRelationInfo configured to the indicated SRS resource. For example, a network device may indicate an SRS resource #a for PUSCH transmission and the terminal device may use the CSI-RS or SS/PBCH or SRS source that is configured as spatial relation information reference to the SRS resource #a as the Tx beam for PUSCH transmission.

For codebook based transmission, the PUSCH transmission can be scheduled by DCI format 0_1 and if the PUSCH transmission is scheduled by DCI format 0_1, the terminal device determines the PUSCH transmission precoder based on an SRI, transmit precoding matrix index (TPMI) and transmission rank, where the SRI, TPMI and transmission rank are given by the DCI fields of SRS resource indicator and precoding information and number of layers. The TPMI is used to indicate the precoder to be applied over the layers {0…ν-1} , and that corresponds to the SRS resource selected by the SRI when multiple SRS resources are configured in the SRS resource set for codebook based transmission, or if a single SRS resource is configured, TPMI is used to indicate the precoder to be applied over the layers {0…ν-1} and that corresponds to the SRS resource.

The Tx beam indication method for non-codebook-based PUSCH is similar to that of codebook-based PUSCH. For non-codebook based transmission, the PUSCH transmission can be scheduled by DCI format 0_1 and if the PUSCH transmission is scheduled by DCI format 0_1, the terminal device determines the precoder and transmission rank based on the SRI when multiple SRS resources are configured in the SRS resource set non-codebook based transmission, where the SRI is given by the SRS resource indicator in the DCI. The terminal device may perform one-to-one mapping from the indicated SRI (s) to the indicated demodulation reference signal (DM-RS) port (s) and their corresponding PUSCH layers {0 …ν-1} are given by DCI format 0_1. For non-codebook-based transmission, the terminal device can calculate the precoder used for the transmission of the SRS based on a measurement of an associated non-zero power (NZP) CSI-RS resource.

In both non-codebook based transmission and codebook based transmission, all of the SRS resources in the same set are configured with same time domain behaviour. When transmitting SRS, the uplink channel tracking performance is good if the SRS resource is configured with small transmission periodicity, and the overhead is reduced if the SRS resource used for the SRS is configured with large transmission periodicity.

SUMMARY

Embodiments of the present application provide a method, terminal device, and a network device for SRS transmission that provide performance improvements.

Through the embodiments enabling the network device to configure the SRS resources, limits on network device implementation on SRS resource configuration are overcome and the capability for both efficient usage of uplink resource for SRS transmission and good uplink channel estimation performance is provided. In addition, dynamic scheduling of PUSCH transmissions can take place.

According to an aspect, there is provided a method for transmitting a sounding reference signal (SRS) resource, comprising: receiving, by a terminal device, SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information; determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission; and transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour.

According to an aspect, there is provided a terminal device for transmitting a sounding reference signal (SRS) resource, comprising: a communication unit to receive SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information; and a processing unit configured to: determine which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission; and control the communication unit to transmit an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour.

According to an aspect, there is provided a method for initiating transmission by a terminal device of a sounding reference signal (SRS) resource, the method comprising: transmitting, by a network device, SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information; and receiving, at the network device, an SRS resource according to one of the first time domain behaviour and the second time domain behaviour.

According to an aspect, there is provided a network device for initiating transmission by a terminal device of a sounding reference signal (SRS) resource, the network device comprising: a communication unit; and a processing unit to control the communication unit to transmit SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information, wherein the communication unit is configured to receive an SRS resource according to one of the first time domain behaviour and the second time domain behaviour.

According to an aspect, there is provided a computer-readable medium having computer-executable instructions to cause one or more processors of a computing device to carry out the method of any one of the embodiments.

According to an aspect, there is provided a terminal device, comprising: a processor; and a memory configured to store a computer program capable of being run in the processor, wherein the processor is configured to run the computer program to perform the steps in the method of any of the terminal device method embodiments.

According to an aspect, there is provided a network device, comprising: a processor; and a memory configured to store a computer program capable of being run in the processor, wherein the processor is configured to run the computer program to perform the steps in the method of any of the network device method embodiments.

These and other aspects of the present application may become more readily apparent from the following description of the embodiments.

BRIEF DESCRIPTION OF THE DRAWINGS

Embodiments will now be described, by way of example only, with reference to the accompanying drawings, in which:

Figure 1 shows a schematic illustration of a system including a terminal device and a network device;

Figure 2 shows a schematic illustration of a terminal device;

Figure 3 shows a flowchart of the operation of the terminal device of Figure 2 according to a first embodiment;

Figure 4 shows a flowchart of the operation of the terminal device of Figure 2 according to the first embodiment;

Figure 5 shows a schematic illustration of a network device;

Figure 6 shows a flowchart of the operation of the network device of Figure 5 according to the first embodiment;

Figure 7 shows a flowchart of the operation of the network device of Figure 5 according to the first embodiment;

Figure 8 shows a flowchart of the operation of the terminal device of Figure 2 according to a second embodiment;

Figure 9 shows a flowchart of the operation of the network device of Figure 5 according to the second embodiment;

Figure 10 shows a schematic illustration of a terminal device according to an embodiment; and

Figure 11 shows a schematic illustration of a network device according to an embodiment.

DETAILED DESCRIPTION

Technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the accompanying drawings.

These technical solutions may be applied to a 5G NR communication system. For example, they may be used for FR2. FR2 includes frequency bands from 24.25 GHz to 52.6 GHz. Generally, in FR2, to receive multi-TRP transmission, the UE would use multiple Rx antenna panels and use a different panel to receive PDCCH/PDSCH from different TRPs. The current beam reporting methods cannot support UE Rx panel-specific beam measurement reports.

It is to be understood that these technical solutions may also be applied to various communication systems, for example, a Global System of Mobile communication (GSM) , a Code Division Multiple Access (CDMA) system, a Wideband Code Division Multiple Access (WCDMA) system, a General Packet Radio Service (GPRS) system, a Long Term Evolution (LTE) system, an LTE Frequency Division Duplex (FDD) system, an LTE Time Division Duplex (TDD) system, a Universal Mobile Telecommunication System (UMTS) , a Worldwide Interoperability for Microwave Access (WiMAX) communication system, and New Radio (NR) or future 5G systems, and the like.

The technical solutions may be applied to a variety of communication systems, for example, an orthogonal frequency division multiplexing (OFDM) system.

A terminal device in the embodiments may refer to a user equipment (UE) , an access terminal, a subscriber unit, a subscriber station, a mobile station, a remote station, a remote terminal, a mobile device, a user terminal, a terminal, a wireless communication device, a user agent, or a user apparatus. The access terminal may be a cellular phone, a cordless phone, an SIP (Session Initiation Protocol) phone, a WLL (Wireless Local Loop) station, a PDA (Personal Digital Assistant) , a handheld device having a wireless communication function, a computing device, or another processing device connected to a wireless modem, a vehicle-mounted device, a wearable device, a terminal device in a future 5G network, or a terminal device in a future evolutional PLMN (Public Land Mobile Network) , and the like. However, the embodiments of the present application are not limited thereto.

A network device in the embodiments of the present application may be a device for communicating with the terminal device. Specifically, the network device may be a Base Transceiver Station (BTS) in a GSM system or a CDMA system, a NodeB (NB) in a WCDMA system, an Evolutional NodeB (eNB or eNodeB) in an LTE system, a wireless controller, or a relay station, an access point, a vehicle-mounted device, a wearable device, a network device in 5G network (for example, gNB) , or a network device in a future evolutional Public Land Mobile Network (PLMN) , etc. The network device may include a transmission-reception point (TRP) of a base station (for example, a gNB) . However, the embodiments of the present application are not limited thereto.

A transmission point (TP) is a set of geographically co-located transmit antennas (e.g. antenna array (with one or more antenna elements) ) for one cell or part of one cell. Transmission Points can include base station (ng-eNB or gNB) antennas, remote radio heads, a remote antenna of a base station, etc. One cell can include one or multiple transmission points. For a homogeneous deployment, each transmission point may correspond to one cell.

A reception point (RP) is a set of geographically co-located receive antennas (e.g. antenna array (with one or more antenna elements) ) for one cell or part of one cell. Reception Points can include base station (ng-eNB or gNB) antennas, remote radio heads, a remote antenna of a base station, and so on. One cell can include one or multiple reception points. For a homogeneous deployment, each reception point may correspond to one cell.

A transmission-reception point (TRP) is a set of geographically co-located antennas (e.g. antenna array (with one or more antenna elements) ) supporting TP and/or RP functionality.

A wireless communication network includes one or more fixed base infrastructure units forming a network distributed over a geographical region. As an example, the network device may serve a number of terminal devices within a serving area, for example, a cell, or within a cell sector. In some systems, one or more network devices are coupled to a controller (such as a wireless controller) forming an access network that is coupled to one or more core networks. Base stations (e.g. gNB) are examples of network devices in the wireless network, the serving area of which may or may not overlap with each other.

A communication system in general may include a terminal device and a network device. The network device is configured to provide communication services for the terminal device and access to a core network. The terminal device accesses the network by searching a synchronous signal, broadcast signal and the like transmitted by the network device, thereby communicating with the network.

Figure 1 shows a schematic illustration of a communication system 10 according to various embodiments. The system 10 comprises a terminal device 100 and a network device 200 that are in communication with each other. As shown in Figure 1, the terminal device 100 and network device 200 can perform uplink transmission (terminal device 100 to network device 200) and downlink transmission (network device 200 to terminal device 100) .

It will be appreciated that in practical implementations of embodiments, there may be many such terminal devices and/or network devices, but one of each will be described with relation to Figure 1 for ease of explanation.

In these embodiments, the communication system 10 is the 5G NR communication system. However, embodiments of the invention are not limited to this and any suitable communication system could be used instead, as discussed above.

In these embodiments, the terminal device 100 is a UE. More specifically, in this embodiment, the terminal device 100 is a smartphone. However, embodiments of the invention are not limited to this and any suitable terminal device 100 capable of communicating with a network device 200 could be used instead. Examples include a PDA, tablet, laptop computer, or other suitable computer devices.

In these embodiments, the network device 200 is a base station. More specifically, the network device 200 is a gNB. However, embodiments of the invention are not limited to this and any suitable network device 200 capable of communicating with a terminal device 100 could be used instead.

Figure 2 shows a schematic illustration of the terminal device 100 of the communication system 10 of Figure 1. As shown in Figure 1, the terminal device 100 comprises a communication unit 110 and a processing unit 120.

The communication unit 110 is configured to communicate with the network device 200. More specifically, the communication unit 110 is configured to perform both uplink communication (i.e. terminal device 100 to network device 200) and downlink communication (i.e. network device 200 to terminal device 100)

The processing unit 120 is configured to control the overall functionality of the terminal device 100, including that of the communication 110. This includes controlling the communication unit 110 to perform both uplink and downlink communications, as well as processing signals received through the downlink transmissions.

In some embodiments, an SRS resource can be configured with two different time domain behaviours. In a first example, one SRS resource can be configured with two resource types. A first resource type is set to periodic and a second resource type is set to aperiodic. Since the SRS resource is configured with the first resource type being set to periodic, the SRS resource is configured with slot level periodicity and slot level offset. The SRS resource can be transmitted according to both the first resource type and the second resource type. According to the first resource type being set to periodic, the SRS resource is transmitted in the slots according to the configured slot level periodicity and slot level offset. According to the second resource type being set to aperiodic, the SRS resource transmission can be triggered by a DCI. In a second example, one SRS resource can be configured with two resource types. A first resource type is set to semi-persistent and a second resource type is set to aperiodic. Since the SRS resource is configured with the first resource type being set to semi-persistent, the SRS resource is configured with slot level periodicity and slot level offset. The SRS resource can be transmitted according to both the first resource type and the second resource type. According to the first resource type being set to semi-persistent, the transmission of the SRS resource can be activated by an activation command (e.g. a medium access control (MAC) control element (CE) activation command) and deactivated by a deactivation command (e.g. a MAC CE deactivation command) . According to the second resource type being set to aperiodic, the SRS resource transmission can be triggered by a DCI. These various examples will be discussed in detail below.

The terminal device transmitting an SRS resource comprises transmitting an SRS using the parameters defined in the SRS resource (e.g. using the Tx beam indicated by SRS-SpatialRelationInfo) .

Figure 3 shows a flowchart of the operation of the terminal device 100 of Figure 2 according to a first embodiment. Through the flowchart of Figure 3 discussed below, the terminal device 100 can be configured with two different time domain behaviours for codebook or non-codebook SRS transmission.

At step S1, the terminal device 100 receives information for codebook or non-codebook based transmission from the network device 200, the SRS information comprising at least one SRS resource, and comprising information on a first time domain behaviour and a second time domain behaviour.

In this first embodiment, step S1 involves receiving a configuration of an SRS resource set comprising an SRS resource, the SRS resource comprising first time domain behaviour and second time domain behaviour. The configuration of the SRS resource set comprising the SRS resource, the SRS resource comprising first time domain behaviour and second time domain behaviour, is received from the network device 200, as described below.

In this first embodiment, step S1 involves receiving the radio resource control (RRC) parameter SRS-Config in the BWP-UplinkDedicated information element (IE) . However, embodiments are not limited to this, and any other suitable parameters could instead be used for the configuration.

In this first embodiment, the SRS resource set comprises a single SRS resource configured for codebook based transmission (i.e. with usage of the SRS resource set being set to ‘codebook’ ) . However, in alternative embodiments, more than one (e.g. two) SRS resource could be configured within the SRS resource set with usage set to ‘codebook’ . In other alternative embodiments, the SRS resource set is configured for non-codebook based transmission (i.e. with usage set to ‘nonCodebook’ ) , and the SRS resource set can comprise one or more (e.g. up to four) SRS resources.

Furthermore, in this first embodiment, the first time domain behaviour is configured within SRS-Config, using the parameter resourceType. The second time domain behaviour is configured within SRS-Config using the parameter resourceType2nd. However, any suitable alternative parameters could be used instead.

In this first embodiment, the first time domain behaviour (or ‘first resource type’ ) is set to one of ‘aperiodic’ , ‘periodic’ (having a lost level periodicity and slot level offset) , and ‘semi-persistent’ (having a slot level periodicity) , while the second time domain behaviour (or ‘second resource type’ ) is set to a different one of ‘aperiodic’ , ‘periodic’ , and ‘semi-persistent’ . In some embodiments, the terminal device 100 one of the time domain behaviours is set to aperiodic and that the other one is set to periodic or semi-persistent.

At step S2, the terminal device 100 determines which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission. Hence, in this first embodiment, the terminal device 100 determines which of the first time domain behaviour and the second time domain behaviour of the configured SRS resource to use to transmit the SRS resource.

Then at step S3, the terminal device 100 transmits the SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour.

In some embodiments, steps S2-S3 involve determining to transmit the SRS resource using both the first time domain behaviour and the second time domain behaviour. This will be discussed in more detail with regard to Figure 4.

Specifics regarding how steps S2-S3 are performed will be discussed with reference to Figure 4.

Figure 4 shows a flowchart of the operation of the terminal device 100 of Figure 2. Step S11 of Figure 4 corresponds to step S1 of Figure 3, and a repeated discussion thereof is not needed.

Steps S12A, S13B, and S13C correspond to alternative options for how step S2 can be performed. Steps S13A, S14B, and S14C correspond to alternative options for how step S3 can be performed. Which of these steps take place is dependent on which time domain behaviours among periodic, semi-persistent, and aperiodic the first resource type and second resource type are set to.

Steps S12A-S13A relate to the periodic time domain behaviour. Hence, if one of the first time domain behaviour and the second time domain behaviour is set to periodic, then the terminal device 100 determines to perform SRS transmission at step S12A, and transmits the SRS resource using the periodic behaviour at step S13A. As mentioned above, the periodic resource type includes a slot level periodicity and a slot level offset. At step S13A, the terminal device 100 periodically transmits the SRS resource using the configured slot level periodicity and slot level offset.

Put differently, at steps S12A-S13A, in response to determining that one of the first time domain behaviour and the second time domain behaviour is a periodic behaviour, the terminal device 100 transmits the SRS resource according to the periodic behaviour.

Steps S12B-S14B relate to the semi-persistent time domain behaviour. If one of the first time domain behaviour and the second time domain behaviour is set to semi-persistent, then the SRS transmission at step S14B can take place. Whether or not the SRS transmission at step S14B does take place is dependent on whether a MAC CE command is received at step S12B.

Specifically, at step S12B, the terminal device 100 can receive a MAC CE activation command from the network device 200. Upon receiving the MAC CE activation command, the method proceeds to step S13B in which the terminal device 100 determines to transmit the SRS resource, using the semi-persistent time domain behaviour, and performs this transmission at step S14B. As mentioned above, the semi-persistent resource type includes a slot level periodicity and a slot level offset. At step 14B, the terminal device 100 periodically transmits the SRS using the configured slot level periodicity and slot level offset.

Put differently, at steps S12B-S14B, in response to determining both that one of the first time domain behaviour and the second time domain behaviour is semi-persistent, and that an activation command has been received, the terminal device 100 transmits the SRS resource according to the semi-persistent behaviour.

In some embodiments, the terminal device 100 also receives a MAC CE deactivation command after step S13B. In this case, the terminal device 100 stops periodically transmitting the (semi-persistent) SRS using the configured slot level periodicity and slot level offset.

If one of the first resource type and the second resource type is set to periodic, and the other is set to semi-persistent, the slot level periodicities and/or slot level offsets of the periodic and semi-persistent resource types may be different.

Steps S12C-S14C relate to the aperiodic time domain behaviour. If one of the first time domain behaviour and the second time domain behaviour is set to aperiodic, then the SRS transmission at step S14C can take place. Whether or not the SRS transmission at step S14C does take place is dependent on whether a DCI trigger is received at step S12C.

Specifically, at step S12C, the terminal device 100 can receive a DCI trigger from the network device 200. Upon receiving the DCI trigger, the method proceeds to step S13C in which the terminal device 100 determines to transmit the SRS resource, using the aperiodic time domain behaviour, and performs this transmission at step S14C.

Put differently, at steps S12c-S14C, in response to determining both that one of the first time domain behaviour and the second time domain behaviour is aperiodic and that a DCI trigger has been received, the terminal device 100 transmits the SRS resource according to the aperiodic behaviour.

It can therefore be seen that step S2 involves one or more of steps S12A, S13B, and S14B, while step S3 involves one or more of steps S13A, S14B, and S14C. If steps S13B-S14B are to be performed, then step S12B needs to be performed. If steps S13C-S14C are to be performed, then step S12C needs to be performed.

Which of these steps takes place is dependent on the configuration of the first and second time domain behaviours (i.e. periodic, aperiodic, or semi-persistent) , as well as whether further transmissions are received from the network device 200 (e.g. a MAC CE activation command or a DCI trigger) .

In one example, the SRS resource is configured with two resource types, a first resource type is set to periodic and a second resource type is set to aperiodic. Since the SRS resource is configured with the first resource type being set to periodic, the SRS resource is configured with slot level periodicity and slot level offset. The SRS resource can be transmitted according to both the first resource type and the second resource type. According to the first resource type being set to periodic, the SRS resource is transmitted in the slots according to the configured slot level periodicity and slot level offset. According to the second resource type being set to aperiodic, the SRS resource transmission can be triggered by a DCI.

In this example, the periodic SRS transmission takes place upon configuration of the SRS resource, while aperiodic transmission only takes place when (or if) the triggering DCI is received. Hence, either just the periodic SRS transmission can be performed, or both the periodic and aperiodic SRS transmission can be performed.

In a second example, one SRS resource can be configured with two resource types, a first resource type is set to semi-persistent and a second resource type is set to aperiodic. Since the SRS resource is configured with the first resource type being set to semi-persistent, the SRS resource is configured with slot level periodicity and slot level offset. The SRS resource can be transmitted according to both the first resource type and the second resource type. According to the first resource type being set to semi-persistent, the transmission of the SRS resource can be activated by a MAC CE activation command and deactivated by an MAC CE deactivation command. According to the second resource type being set to aperiodic, the SRS resource transmission can be triggered by a DCI.

In this example, the semi-persistent SRS transmission only takes place upon receipt of a MAC CE activation command, while the aperiodic transmission only takes place when (or if) the triggering DCI is received. Hence, either just the semi-persistent SRS transmission can be performed, just the aperiodic SRS transmission can be performed, or both the semi-persistent and aperiodic SRS transmission can be performed.

By configuring the SRS resource with two different time domain behaviours in this way (e.g. aperiodic and periodic or aperiodic and semi-persistent) , the flexibility for the network device 200 in terms of scheduling SRS transmissions is increased.

This flexibility in choice of time domain behaviour allows the network device 200 to schedule SRS transmissions in a way that supports both efficient usage of uplink resources for SRS transmission and good uplink channel estimation performance, allowing the advantages associated with both a small transmission periodicity (e.g. good uplink channel tracking performance) and with a large transmission periodicity (e.g. reduced overhead of resources used for the SRS resource) to be achieved. For example, in some embodiments, the terminal device 100 can perform SRS transmission using both the first time domain behaviour and the second time domain behaviour. In other words, one or more of step S12A, steps S12B-S13B, and steps S12C-S13C take place.

The SRS resource set according to this first embodiment can also be used for scheduling PUSCH transmissions (e.g. according to the discussion given above) . For example, in addition to the features discussed above in relation to this embodiment, the network device 200 may transmit a DCI scheduling a PUSCH transmission (i.e. transmit a PUSCH grant) to the terminal device 100, including an SRS resource indicator to indicate an SRS resource to be used for the PUSCH transmission. In response, the terminal device 100 transmits the requested PUSCH according to the indicated SRS resource to the network device 200.

The first embodiment will now be discussed from the perspective of the network device 200, which is in communication with the terminal device 100.

Figure 5 shows a schematic illustration of the network device 200, Figure 6 shows a flowchart of the operation of the network device 200 of Figure 5, while Figure 7 shows a second flowchart of the operation of the network deice 200 of Figure 5. The flowchart of Figure 6 showing the operations of the network device 200 generally corresponds to the flowchart of Figure 3, but from the perspective of the network device 200. Similarly the flowchart of Figure 7 showing the operations of the network device 200 generally corresponds to the flowchart of Figure 4, but from the perspective of the network device 200. As such, corresponding considerations apply.

As shown in Figure 5, the network device 200 comprises a communication unit 210 and a processing unit 220.

The communication unit 210 is configured to communicate with the terminal device 100. More specifically, the communication unit 210 is configured to perform both uplink communication (i.e. terminal device 100 to network device 200) and downlink communication (i.e. network device 200 to terminal device 100) .

The processing unit 220 is configured to control the overall functionality of the network device 200, including that of the communication unit 210. This includes controlling the communication unit 210 to perform both uplink and downlink communications, as well as processing signals received through the uplink transmissions.

Figure 6 shows a flowchart of the operation of the network device 200 of Figure 4. As mentioned above, the flowchart of Figure 6 showing the operations of the network device 200 generally corresponds to the flowchart of Figure 3, but from the perspective of the network device 200, and corresponding provisions apply. Through the flowchart of Figure 6 discussed below, the network device 200 can configure the terminal device 100 with two different time domain behaviours for codebook or non-codebook SRS transmission.

At step S31, the network device 200 transmits SRS information for codebook or non-codebook based transmission to the terminal device 100, the SRS information comprising at least one SRS resource, and comprising information on a first time domain behaviour and a second time domain behaviour.

At step S32, the network device 200 receives an SRS resource, which has been transmitted using one of the first time domain behaviour and the second time domain behaviour.

The above detailed discussion in relation to the flowchart of Figure 3 applies correspondingly to this flowchart of Figure 6, and a repeated discussion is therefore not needed. In particular, steps S1 and S31 are corresponding, while steps S3 and S32 are corresponding.

Figure 7 shows a flowchart of the operation of the network device 200 of Figure 6. The flowchart of Figure 7 showing the operations of the network device 200 generally corresponds to the flowchart of Figure 4, but from the perspective of the network device 200, and corresponding provisions apply.

At step S41, the network device 200 transmits SRS information for codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour and second time domain behaviour information. Step S41 of Figure 7 corresponds to step S31 of Figure 6, and a repeated discussion thereof is not needed.

Which steps out of S42A, S42B-S43B and S42C-S43C take place is dependent on which time domain behaviours among periodic, semi-persistent, and aperiodic the first resource type and second resource type are set to.

Step S42A relates to the periodic time domain behaviour. Hence, if one of the first time domain behaviour and the second time domain behaviour is set to periodic, then the SRS handling at step S42A takes place. Specifically, as step S42A the network device 200 receives an SRS resource which has been transmitted using the periodic time domain behaviour. Steps S42A corresponds to step S12A, but from the perspective of the network device 200. Hence, a repeated discussion is not needed.

Steps S42B-S43B relate to the semi-persistent time domain behaviour. If one of the first time domain behaviour and the second time domain behaviour is set to semi-persistent, then the SRS handling at step S42B-S43B can take place. Specifically, at step S42B, the network device 200 can transmit a MAC CE activation command to activate SRS transmission using the SRS resource using the semi-persistent time domain behaviour. Upon transmitting the MAC CE activation command, the method proceeds to step S43B in which the network device 200 receives the SRS resource, which has been transmitted by the terminal device 100 using the semi-persistent time domain behaviour. Step S42B corresponds to step S12B, but from the perspective of the network device 200, while step S42B corresponds to S14B from the perspective of the network device 200. Hence, a repeated discussion is not needed.

As previously discussed, in some embodiments, the network device 200 can also transmit a MAC CE deactivation command after step S43B.

Steps S42C-S43C relate to the semi-persistent time domain behaviour. If one of the first time domain behaviour and the second time domain behaviour is set to semi-persistent, then the SRS handling at step S42C-S43C can take place. Specifically, at step S42C, the network device 200 can transmit a DCI to trigger SRS transmission using the SRS resource using the aperiodic time domain behaviour. Upon transmitting the triggering DCI, the method proceeds to step S43C in which the network device 200 receives the SRS using the SRS resource, which has been transmitted by the terminal device 100 using the aperiodic time domain behaviour. Step S42C corresponds to step S12C, but from the perspective of the network device 200, while step S43C corresponds to step S14C from the perspective of the network device 200. Hence, a repeated discussion is not needed.

By configuring the SRS resource with two different time domain behaviours in this way (e.g. aperiodic and periodic or aperiodic and semi-persistent) , the flexibility for the network device 200 is increased in terms of scheduling SRS transmissions is increased.

This flexibility in choice of time domain behaviour allows the network device 200 to schedule SRS transmissions in a way that supports both efficient usage of uplink resources for SRS transmission and good uplink channel estimation performance, allowing the advantages associated with both a small transmission periodicity (e.g. good uplink channel tracking performance) and with a large transmission periodicity (e.g. reduced overhead of resources used for the SRS resource) to be achieved. For example, in some embodiments, the network device 200 can configure the terminal device 100 to perform SRS transmission using both the first time domain behaviour and the second time domain behaviour. In other words, one or more of step S42A, steps S42B-S43B, and steps S42C-S43C take place.

In one example, an SRS resource set according to the above discussion is configured with the following higher layer parameter:

where the higher layer parameter resourceType provides the first configuration of time domain behaviour and the higher layer parameter resourceType2nd provides the second configuration of time domain behaviour.

Hence, it can be seen that in some embodiments, the following SRS parameters are semi-statically configurable by the higher layer parameter SRS-Resource:

- srs-ResourceId determines SRS resource configuration identity.

- Number of SRS ports as defined by the higher layer parameter nrofSRS-Ports and described in sub clause 6.4.1.4 of 3GPP TS 38.214 V15.5.0: "NR; Physical layer procedures for data" .

- Time domain behaviour of SRS resource configuration as indicated by the higher layer parameter resourceType, which may be periodic, semi-persistent, or aperiodic SRS transmission.

- A secondary time domain behaviour of SRS resource configuration as indicated by the higher layer parameter resourceType2nd, which may be periodic, semi-persistent, or aperiodic SRS transmission.

In a variant of the first embodiment, the SRS resource set can be configured with the second resource type (e.g. the higher layer parameter resourceType2nd) only when that SRS resource set is configured for codebook or non-codebook transmission (e.g. when the higher layer parameter usage is set to ‘codebook’ or ‘nonCodebook’ ) In other words, in some embodiments, if the SRS resource is not configured for codebook or non-codebook transmission (i.e.. the higher layer parameter usage for the SRS resource set is not set to ‘codebook’ or ‘nonCodebook’ ) , then a second resource type (e.g. resourceType2nd) is not configured in the SRS resource set.

As discussed in detail above, in some embodiments the SRS information (in step S1 of Figure 3 and step S31 of Figure 6) comprises a configuration of an SRS resource set comprising an SRS resource, the SRS resource comprising first time domain behaviour and second time domain behaviour.

Figure 8 shows a flowchart of the operation of the terminal device 100 according to a second embodiment. Figure 9 shows the corresponding operation of the network device 200 in this embodiment.

This second embodiment (i.e. the embodiment of Figures 8-9) provides a different way of providing two different time domain behaviours to be used for SRS transmission. Specifically, in this second embodiment, the network device 200 configures the terminal device 100 with SRS information comprising two SRS resource sets (both set for codebook transmission or both set of non-codebook transmission) . The SRS resource (s) in the first set comprise different time domain behaviour to the SRS resource (s) in the second set. Hence, flexibility is achieved by configuring the terminal device 100 with more than one time domain behaviour for SRS transmission.

At step S51, the terminal device 100 receives a configuration of a first SRS resource set comprising a first SRS resource configured with first time domain behaviour and a second SRS resource set comprising a second SRS resource configured with second time domain behaviour.

In this second embodiment, step S51 involves receiving the radio resource control (RRC) parameter SRS-Config in the BWP-UplinkDedicated information element (IE) . The SRS-Config parameter is configured with a first SRS-ResourceSet and a second SRS-ResourceSet. However, embodiments are not limited to this, and any other suitable parameters could instead be used for the configuration.

In this second embodiment, the first SRS resource set comprises a single first SRS resource configured for codebook based transmission (i.e. with usage of the first SRS resource set being set to ‘codebook’ ) , and the second SRS resource set comprises a single second SRS resource configured for codebook based transmission (i.e. with usage of the second SRS resource set being set to ‘codebook’ ) . However, in alternative embodiments, more than one (e.g. two) SRS resources are configured with either or both of the SRS resource sets with usage set to ‘codebook’ . In other alternative embodiments, the first and second SRS resource sets are configured for non-codebook based transmission (i.e. with usage set to ‘nonCodebook’ ) , and each SRS resource set comprises one or more (e.g. up to four) SRS resources.

Furthermore, in this second embodiment, the first time domain behaviour is configured by the resourceType parameter within the first SRS-ResourceSet, while the second time domain behaviour is configured by the resourceType parameter within the second SRS-ResourceSet. However, any suitable alternative parameters could be used instead.

In this second embodiment, the first time domain behaviour (or ‘first resource type’ ) is set to one of ‘aperiodic’ , ‘periodic’ (having a slot level periodicity and slot level offset) , and ‘semi-persistent’ (having a slot level periodicity) , while the second time domain behaviour (or ‘second resource type’ ) is set to a different one of ‘aperiodic’ , ‘periodic’ , and ‘semi-persistent’ . In some embodiments, one of the time domain behaviours is set to aperiodic and that the other one is set to periodic or semi-persistent.

At step S52, the terminal device 100 determines whether to transmit the first SRS resource using the first time domain behaviour and/or the second SRS resource using the second time domain behaviour. Then at step S53, the terminal device 100 transmits the determined one (s) of the first SRS resource using the first time domain behaviour and/or the second SRS resource using the second time domain behaviour.

Corresponding provisions to the above detailed discussion steps S2-S3 of Figure 3, and steps S12A-S13A, S12B-S14B, and S12C-S14C of Figure 4 apply for steps S52-S53, as discussed in more detail below.

For example, in relation to the periodic time domain behaviour (similarly to steps S12A-S13A of Figure 4) , if the first time domain behaviour is set to periodic, then the terminal device 100 transmits the first SRS resource using the periodic time domain behaviour. The periodic resource type includes a slot level periodicity and a slot level offset, and the terminal device 100 periodically transmits the first SRS resource using this slot level periodicity and slot level offset. Alternatively, if the second time domain behaviour is set to periodic, then the terminal device 100 transmits the second SRS resource using the periodic time domain behaviour. The periodic resource type includes a slot level periodicity and a slot level offset, and the terminal device 100 periodically transmits the first SRS resource using this slot level periodicity and slot level offset.

In relation to semi-persistent time domain behaviour (similarly to steps S12B-S14B of Figure 4) , if the first time domain behaviour is set to semi-persistent, then the first SRS resource can be transmitted using the semi-persistent time behaviour. Whether or not the terminal device 100 does transmit the first SRS resource using the semi-persistent time domain behaviour is dependent on whether a MAC CE command is received from the network device 200. Specifically, the terminal device 100 can receive a MAC CE activation command from the network device 200. Upon receiving the MAC CE activation command, the terminal device 100 transmits the first SRS resource using the semi-persistent time domain behaviour. As mentioned above, the semi-persistent resource type includes a slot level periodicity and a slot level offset. Hence, the terminal device 100 periodically transmits the first SRS resource using the configured slot level periodicity and slot level offset. In some embodiments, the terminal device 100 subsequently receives a MAC CE deactivation command. In this case, the terminal device 100 stops periodically transmitting the (semi-persistent) first SRS resource using the configured slot level periodicity and slot level offset.

Alternatively, if the second time domain behaviour is set to semi-persistent, then the second SRS resource can be transmitted using the semi-persistent time behaviour. Whether or not the terminal device 100 does transmit the second SRS resource using the semi-persistent time domain behaviour is dependent on whether a MAC CE command is received from the network device 200. Specifically, the terminal device 100 can receive a MAC CE activation command from the network device 200. Upon receiving the MAC CE activation command, the terminal device 100 transmits the second SRS resource using the semi-persistent time domain behaviour. As mentioned above, the semi-persistent resource type includes a slot level periodicity and a slot level offset. Hence, the terminal device 100 periodically transmits the second SRS resource using the configured slot level periodicity and slot level offset. In some embodiments, the terminal device 100 subsequently receives a MAC CE deactivation command. In this case, the terminal device 100 stops periodically transmitting the (semi-persistent) first SRS resource using the configured slot level periodicity and slot level offset.

If one of the first resource type and the second resource type is set to periodic and the other is set to semi-persistent, the slot level periodicities and/or slot level offsets of the periodic and semi-persistent resource types may be different.

In relation to aperiodic time domain behaviour (similarly to steps S12C-S14C) , if the second time domain behaviour is set to aperiodic, the terminal device 100 can transmit the first SRS resource using the aperiodic behaviour. Whether or not the terminal device 100 does transmit the first SRS resource is dependent on whether a triggering DCI is received at step S12C. Specifically, the terminal device 100 can receive a DCI triggering an aperiodic SRS transmission. Upon receiving the DCI trigger, the terminal device 100 transmits the first SRS resource using the aperiodic time domain behaviour.

Alternatively, if the second time domain behaviour is set to aperiodic, the terminal device 100 can transmit the second SRS resource using the aperiodic behaviour. Whether or not the terminal device 100 does transmit the second SRS resource is dependent on whether a triggering DCI is received at step S12C. Specifically, the terminal device 100 can receive a DCI triggering an aperiodic SRS transmission. Upon receiving the DCI trigger, the terminal device 100 transmits the second SRS resource using the aperiodic time domain behaviour.

It can therefore be seen that steps S52-S53 involve one or more of these periodic, semi-persistent, and aperiodic SRS transmissions.

By configuring the terminal device 100 with a first SRS resource set with one or more SRS resources having a first time domain behaviour, and a second SRS resource set with one or more SRS resources having a second time domain behaviour in this way (e.g. aperiodic and periodic or aperiodic and semi-persistent) , the flexibility for the network device 200 in terms of scheduling SRS transmissions is increased.

This flexibility in choice of time domain behaviour allows the network device 200 to schedule SRS transmissions in a way that supports both efficient usage of uplink resources for SRS transmission and good uplink channel estimation performance, allowing the advantages associated with both a small transmission periodicity (e.g. good uplink channel tracking performance) and with a large transmission periodicity (e.g. reduced overhead of resources used for the SRS resource) to be achieved. For example, in some embodiments, the terminal device 100 can perform SRS transmission using both the first time domain behaviour and the second time domain behaviour (by transmitting a first SRS resource from the first SRS resource set according to the first time domain behaviour, and transmitting a second SRS resource from the second SRS resource set according to the second time domain behaviour) . In other words, one or more of steps S12A-S13A, steps S12B-S13B, and steps S12C-S13C take place.

In some embodiments, the method of Figure 8 can proceed to steps S54-S55. However, it will be appreciated that steps S54-S55 are optional and that steps S51-S53 can be performed without steps S54-S55. In addition, although step S54 is shown as being performed after steps S52-S53 in Figure 8, in some embodiments step S54 can be performed before step S53, or before step S52. Similarly step S55 can also be performed before step S53 or step S52 in some embodiments, provided that step S55 takes place after step S54.

Steps S54-S55 relate to how a PUSCH transmission can be dynamically scheduled by a DCI (i.e. a DCI including a PUSCH grant) in this embodiment in which two SRS resource sets are configured for codebook (or for non-codebook) transmission. In particular, the following discussion of steps S54-S55 explains how the SRS resource indicator in the DCI can indicate an SRS resource from one of the two sets.

At step S54, the terminal device 100 receives a DCI scheduling a PUSCH transmission (i.e. a DCI comprising a PUSCH grant) , the DCI comprising an SRS resource indicator indicating an SRS resource to be used for the PUSCH transmission. Then, at step S55, the terminal device 100 performs a PUSCH transmission according to the indicated SRS resource.

In embodiments relating to codebook transmission (i.e. when usage for the first and second SRS resource sets is set to ‘codebook’ ) , the PUSCH can be scheduled with a DCI format 0_1. The number of bits of the SRS resource indicator in the DCI format is

where N _SRS, 0 is the number of configured SRS resources in the first SRS resource set (e.g. one or two) associated with the higher layer parameter usage of value ‘codebook’ and N _SRS, 1 is the number of configured SRS resources in the second SRS resource set (e.g. one or two) associated with the higher layer parameter usage of value ‘codebook’ . The terminal device 100 determines its PUSCH transmission precoder based on SRI, TMPI and the transmission rank, which are given by the DCI fields of SRS resource indicator, precoding information and number of layers. For the PUSCH transmission, one SRS resource can be indicated based on the SRS resource indicator from within either the first SRS resource set or the second resource set. Hence, in some embodiments, the SRS resource indicator consists of exactly and no more than

bits.

In this way, it can be seen that the number of bits for the SRS resource indicator is determined based on the number of SRS resources in the first SRS resource set and the number of SRS resources in the second SRS resource sets. In other words, the SRS resource indicator in the DCI can be used to indicate any of the SRS resources from either SRS resource set for the PUSCH transmission.

In alternative embodiments relating to codebook transmission (i.e. when usage for the first and second SRS resource sets is set to ‘codebook’ ) the PUSCH can also be scheduled with a DCI format 0_1. However, in this alternative, the number of bits of the SRS resource indicator in the DCI format is

where N _SRS, 0 is the number of configured SRS resources in the first SRS resource set associated with the higher layer parameter usage of value ‘codebook’ . The terminal device 100 determines its PUSCH transmission precoder based on SRI, TMPI and the transmission rank, which are given by DCI fields of SRS resource indicator, precoding information and number of layers. For the PUSCH transmission, one SRS resource can be indicated based on the SRS resource indicator from within the first SRS resource set. Hence, the SRS resource indicator consists of exactly and no more than

bits.

In this example, the ‘first’ SRS resource set may refer to the SRS resource set having the lowest ID (e.g. set using SRS-ResourceSetID) among the first SRS resource set and the second SRS resource set. Alternatively, the ‘first’ SRS resource set may refer to the SRS resource set having the highest ID (e.g. set using SRS-ResourceSetID) among the first SRS resource set and the second SRS resource set. Further alternatively, the ‘first’ SRS resource may be one of the first SRS resource set and second SRS resource set which has been configured with a higher layer parameter to indicate that this SRS resource set may be associated with the field of SRS resource indicator in the DCI.

In this way, it can be seen that the number of bits for the SRS resource indicator is determined based on the number of SRS resources in only the one of the SRS resource sets, and the SRS resource indicator in the DCI can be used to indicate any of the SRS resources in that SRS resource set. Hence, an SRS resource can be indicated without it being needed to increase the number of bits in the SRS resource indicator compared to the current design.

In embodiments relating to non-codebook transmission (i.e. when usage for the first and second SRS resource sets is set to ‘nonCodebook’ ) , the PUSCH can be scheduled with a DCI format 0_1. The number of bits of the SRS resource indicator in the DCI format is

where N _SRS=N _SRS, 0+N _SRS, 1, where N _SRS, 0 is the number of configured SRS resources in the first SRS resource set (e.g. one to four) associated with the higher layer parameter usage of value ‘nonCodebook’ and N _SRS, 1 is the number of configured SRS resources in the second SRS resource set (e.g. one to four) associated with the higher layer parameter usage of value ‘nonCodebook’ . The terminal device 100 determines its PUSCH transmission precoder based on SRI, which is given by the DCI field of SRS resource indicator. For the PUSCH transmission, one or multiple SRS resources can be indicated based on the SRI from within either the first SRS resource set or the second resource set. The indicated SRS resources may be within the same SRS resource set. Hence, in some embodiments, the SRS resource indicator consists of exactly and no more than

bits, where N _SRS=N _SRS, 0+N _SRS, 1.

In alternative embodiments relating to non-codebook transmission (i.e. when usage for the first and second SRS resource sets is set to ‘nonCodebook’ ) , the PUSCH can be scheduled with a DCI format 0_1. The number of bits of the SRS resource indicator in the DCI format is

where N _SRS=N _SRS, 0+N _SRS, 1, where N _SRS=N _SRS, 0 and N _SRS, 0 is the number configured SRS resources in the first SRS resource set associated with the higher layer parameter usage of value ‘nonCodebook’ . The terminal device 100 then determines its PUSCH transmission precoder based on SRI which is given by the DCI field of the SRS resource indicator. For the PUSCH transmission, one or more SRS resources can be indicated based on the SRI from within the same SRS resource set. Hence, in some embodiments, the SRS resource indicator consists of exactly and no more than

bits, where N _SRS=N _SRS, 0.

Figure 9 shows a flowchart of the operation of the network device 200 in cooperation with the method performed by the terminal device 100 in the flowchart of Figure 8. Hence, the flowchart of Figure 9 showing the operations of the network device 200 generally corresponds to the flowchart of Figure 8, but from the perspective of the network device 200, and corresponding provisions apply.

At step S61, the network device 200 transmits a first SRS resource set comprising a configuration of a first SRS resource with first time domain behaviour, and a second SRS resource set comprising a configuration of a second SRS resource with second time domain behaviour, to the terminal device 100.

At step S62, the network device 200 receives the first SRS resource which has been transmitted using the first time domain behaviour and/or the second SRS resource which has been transmitted using the second time domain behaviour.

As discussed above, steps S53-S54 of Figure 8 are optional. Correspondingly, steps S63-S64 of Figure 9 are optional.

At step S63, the network device 200 transmits a DCI scheduling a PUSCH transmission, the DCI comprising an SRS resource indicator indicating an SRS resource to be used for the PUSCH transmission.

At step S64, the network device 200 receives the PUSCH transmission which has been transmitted according to the indicated SRS resource.

As discussed above, steps S61-S64 of Figure 9 generally correspond to steps S51-S54 of Figure 8 and corresponding provisions apply. A repeated discussion thereof is not needed.

As discussed above, in some embodiments, a network device 200 configures a terminal device 100 with two SRS resource sets for codebook (or non-codebook) based transmission. For codebook based transmission, the terminal device 100 may be configured with two higher layer parameters SRS-resourceSet with the higher layer parameter usage to ‘codebook’ . Hence, the terminal device 100 is configured with a first SRS resource set with the higher layer parameter usage to ‘codebook’ and a second SRS resource set associated with the higher layer parameter usage to ‘codebook’ . For non-codebook based transmission, the terminal device 100 may be configured with two higher layer parameters SRS-resourceSet with the higher layer parameter usage to ‘nonCodebook’ . Hence, the terminal device 100 is configured with a first SRS resource set with the higher layer parameter usage to ‘nonCodebook’ and a second SRS resource set associated with the higher layer parameter usage to ‘nonCodebook’ .

In some embodiments, for codebook or non-codebook based transmission, the number of SRS resources configured in the first SRS resource set is equal to the number of SRS resources configured in the second SRS resource set. Hence, the terminal device 100 can expect that the number of SRS resources configured in the first SRS resource set is equal to the number of SRS resources configured in the second SRS resource set.

In some such embodiments in which the number of SRS resources configured in the first SRS resource set is equal to the number of SRS resources configured in the second SRS resource set, the SRS resource (s) in the first SRS resource set and the SRS resource (s) in the second SRS resource set have the same spatial relation information resource-wise. Hence, the terminal device 100 can expect that the SRS resources in the first SRS resource set and in the second SRS resource set have same spatial relation info resource-wise.

In some such embodiments in which the SRS resource (s) in the first SRS resource set and the SRS resource (s) in the second SRS resource set have the same spatial relation information resource-wise, the SRS resource indicator in a DCI scheduling a PUSCH transmission may have a number of bits that is dependent on only one of the SRS resource sets (i.e. dependent only on N _SRS, 0 (and not N _SRS, 1) in the above discussions) , since the other SRS resource set does not provide any additional spatial relation information. Hence, the terminal device can expect that the SRS resources in the first SRS resource set provides spatial relation info resource-wise to the SRS resources in the second SRS resource set.

In some embodiments, the SRS resources in the first SRS resource set provide spatial relation information to the SRS resources in the second SRS resource set.

In some embodiments, for codebook, or non-codebook based transmission, one of the first SRS resource set and the second SRS resource set is configured with the aperiodic time domain behaviour (e.g. the higher layer parameter resourceType is set to ‘aperiodic’ ) , while the other resource set is configured with periodic or semi-persistent time domain behaviour (e.g. with higher layer parameter resourceType set to ‘periodic’ or ‘semi-persistent’ ) . Hence, the terminal device 100 can expect that the first SRS resource set is configured aperiodic time domain behaviour and that second SRS resource set is configured with periodic or semi-persistent time domain behaviour.

In this way, the periodic/semi-persistent SRS resource can take place periodically, while allowing further aperiodic SRS transmissions to be scheduled when desired. As such, the network device 200 has flexibility in scheduling SRS transmissions from the terminal device 100, allowing the network device 200 to schedule PUSCH transmissions in a way that supports both efficient usage of uplink resource for SRS transmission and good uplink channel estimation performance. In other words, the good uplink channel tracking performance associated with both a small transmission periodicity and the reduced overhead of resources used for the SRS associated with a large transmission periodicity can be realised.

In some embodiments, for example relating to non-codebook based transmission, if both the first SRS resource set and the second SRS resource set are configured with associated channel state information reference signal (CSI-RS) , the first SRS resource set and the second SRS resource set are configured with the same associated CSI-RS, and the terminal device 100 can expect that the first SRS resource set and the second SRS resource set are configured with the same associated CSI-RS.

As discussed above, according to some embodiments, the terminal device 100 can be configured with two SRS resource sets for codebook based transmission. Alternatively, the terminal device 100 can be configured with two SRS resource sets for non-codebook based transmission. In each SRS resource set, the terminal device 100 can be configured with one or more SRS resources. For codebook based PUSCH transmission, PUSCH can be scheduled by a DCI format and the DCI field of SRS resource indicator in the DCI indicates one SRS resources of those SRS resources configured in both SRS resource sets. Alternatively, for codebook based PUSCH transmission, the PUSCH can be scheduled by a DCI format and the DCI field of SRS resource indicator in the DCI indicates one SRS resources of those SRS resources configured in one particular SRS resource set configured for codebook based transmission, which can be pre-configured or pre-defined. For non-codebook based PUSCH transmission, the PUSCH can be scheduled by a DCI format and the DCI field of SRS resource indicator in the DCI indicates one or more SRS resources of those SRS resources configured in both SRS resource sets. Alternatively, for non-codebook based PUSCH transmission, the PUSCH can be scheduled by a DCI format and the DCI field of SRS resource indicator in the DCI indicates one or more SRS resources of those SRS resources configured in one particular SRS resource set configured for codebook based transmission, which can be pre-configured or pre-defined.

Figure 10 shows a schematic illustration of a terminal device 300 according to an embodiment. Specifically, Figure 10 shows a schematic illustration of a terminal device 300 configured to perform any of the terminal device methods discussed herein. Such detailed descriptions thereof are omitted here for brevity.

As shown in Figure 10, the terminal device 300 comprises a processor 310 and a memory 320. The processor 310 and the memory 320 may be connected via a bus system. The memory 320 is configured to store programs, instructions or codes. The processor 310 is configured to execute the programs, the instructions or the codes in the memory 320 so as to complete the operations in the terminal device method embodiments herein.

Hence, in embodiments, the memory 320 is configured to store a computer program capable of being run in the processor 310, and the processor 310 is configured to run the computer program to perform steps in any of the terminal device methods discussed herein.

Figure 11 shows a schematic illustration of a network device 400 according to an embodiment. Specifically, Figure 11 shows a schematic illustration of a network device 400 configured to perform any of the network device methods discussed herein. Such detailed descriptions thereof are omitted here for brevity.

As shown in Figure 11, the network device 400 comprises a processor 410 and a memory 420. The processor 410 and the memory 420 may be connected via a bus system. The memory 420 is configured to store programs, instructions or codes. The processor 410 is configured to execute the programs, the instructions or the codes in the memory 420 so as to complete the operations in the network device method embodiments herein.

Hence, in embodiments, the memory 420 is configured to store a computer program capable of being run in the processor 410, and the processor 410 is configured to run the computer program to perform steps in any of the network device methods discussed herein.

In summary, embodiments provide a number of methods for using SRS transmission in codebook based or non-codebook based transmission.

In some methods, one SRS resource (for codebook or non-codebook transmission) can be configured with two different time domain behaviours. The SRS resource can be configured with two higher layer parameters (e.g. resourceType and resourceType2nd) to indicate two different time domain behaviours. The SRS resource can then be transmitted according to both time domain behaviours (e.g. according to both resourceType and resourceType2nd) .

In other methods, a terminal device 100 is provided with two SRS resource sets for codebook based transmission, each set having a configuration of at least one SRS resource, the SRS resources in each set having different time domain behaviours (e.g. set using the higher layer parameter resourceType) . SRS resources in both sets can be transmitted according the time domain behaviours of the SRS resources.

When two SRS resource sets are provided (for codebook based transmission) , in some embodiments, the SRS resource indicator field of a DCI used for scheduling a PUSCH transmission indicates one SRS resource from either of those two SRS resource set. In some embodiments, the SRS resource indicator field of the DCI used for scheduling a PUSCH transmission indicates one SRS resource in the first SRS resource set that is pre-defined or pre-specified.

In other methods, a terminal device 100 is provided with two SRS resource sets for non-codebook based transmission, each set having a configuration of at least one SRS resource, the SRS resources in each set having different time domain behaviours (e.g. set using the higher layer parameter resourceType) . SRS resources in both sets can be transmitted according the time domain behaviours of the SRS resources.

When two SRS resource sets are provided (for non-codebook based transmission) , in some embodiments, the SRS resource indicator field of a DCI used for scheduling a PUSCH transmission indicates one or more SRS resources from either of those two SRS resource sets. In some embodiments, the SRS resource indicator field of the DCI used for scheduling a PUSCH transmission indicates one or more SRS resources from the set that is pre-defined or pre-specified.

Embodiments of the invention can also provide a non-transitory computer-readable medium having computer-executable instructions to cause one or more processors of a computing device to carry out the method of any of the embodiments of the invention.

Examples of non-transitory computer-readable media include both volatile and non-volatile media, removable and non-removable media, and include, but are not limited to: solid state memories; removable disks; hard disk drives; magnetic media; and optical disks. In general, the computer-readable media include any type of medium suitable for storing, encoding, or carrying a series of instructions executable by one or more computers to perform any one or more of the processes and features described herein.

It will be appreciated that the functionality of each of the components discussed can be combined in a number of ways other than those discussed in the foregoing description. For example, in some embodiments, the functionality of more than one of the discussed devices can be incorporated into a single device. In other embodiments, the functionality of at least one of the devices discussed can be split into a plurality of separate (or distributed) devices.

Conditional language such as “may” , is generally used to indicate that features/steps are used in a particular embodiment, but that alternative embodiments may include alternative features, or omit such features altogether.

Furthermore, the method steps are not limited to the particular sequences described, and it will be appreciated that these can be combined in any other appropriate sequences. In some embodiments, this may result in some method steps being performed in parallel. In addition, in some embodiments, particular method steps may also be omitted altogether.

While certain embodiments have been discussed, it will be appreciated that these are used to exemplify the overall teaching of the present invention, and that various modifications can be made without departing from the scope of the invention. The scope of the invention should is to be construed in accordance with the appended claims and any equivalents thereof.

Many further variations and modifications will suggest themselves to those versed in the art upon making reference to the foregoing illustrative embodiments, which are given by way of example only, and which are not intended to limit the scope of the invention, that being determined by the appended claims.

Claims

A method for transmitting a sounding reference signal (SRS) resource, comprising:

receiving, by a terminal device, SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information;

determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission; and

transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour.
The method of claim 1, comprising receiving the SRS information through a radio resource control (RRC) parameter.
The method of claim 1 or claim 2, wherein the SRS information comprises an SRS resource set comprising the configuration of the SRS resource, the SRS resource being configured with the first time domain behaviour and the second time domain behaviour.
The method of claim 3, wherein determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission comprises:

determining that one of the first time domain behaviour and the second time domain behaviour is a periodic behaviour, and

wherein transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

transmitting the SRS resource according to the periodic behaviour.
The method of claim 3 or claim 4, wherein determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission comprises determining both: 1) that one of the first time domain behaviour and the second time domain behaviour is semi-persistent and 2) that an activation command has been received, and,

wherein transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

transmitting the SRS resource according to the semi-persistent behaviour.
The method of claim 5, wherein the activation command is a medium access control (MAC) control element (CE) .
The method of any of claims 3 to 6, wherein determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission comprises determining both: 1) that one of the first time domain behaviour and the second time domain behaviour is an aperiodic behaviour, and 2) that a downlink control information (DCI) has been received, and

wherein transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

transmitting the SRS resource using the aperiodic behaviour.
The method of any one of claims 1 to 7, wherein the first time domain behaviour is aperiodic and the second time domain behaviour is periodic or semi-persistent.
The method of any one of claims 3 to 8, comprising receiving the SRS resource set through an SRS-ResourceSet parameter.
The method of claim 9, comprising receiving the first time domain behaviour through a first resourceType parameter in the SRS-ResourceSet parameter, and receiving the second time domain behaviour through a second resourceType parameter in the SRS-ResourceSet parameter.
The method of claim 1 or claim 2, wherein the SRS information comprises:

a first SRS resource set comprising a configuration of a first SRS resource with the first time domain behaviour; and

a second SRS resource set comprising a configuration of a second SRS resource with the second time domain behaviour.
The method of claim 11, wherein determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission comprises:

determining that one of the first time domain behaviour and the second time domain behaviour is a periodic behaviour, and

wherein transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

transmitting, according to the periodic behaviour, the one of the SRS resources with the time domain behaviour information corresponding to periodic behaviour.
The method of claim 11 or claim 12, wherein determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission comprises:

determining both: 1) that one of the first time domain behaviour and the second time domain behaviour is semi-persistent and 2) that an activation command has been received, and

wherein transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

transmitting, according to the semi-persistent behaviour, the one of the SRS resources with the time domain behaviour information corresponding to semi-persistent behaviour.
The method of claim 13, wherein the activation command is a MAC CE.
The method of any of claims 11 to 14, wherein determining which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission comprises:

determining both: 1) that one of the first time domain behaviour and the second time domain behaviour is an aperiodic behaviour, and 2) that a DCI has been received, and

wherein transmitting, by the terminal device, an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

transmitting, according to the aperiodic behaviour, the one of the SRS resources with the time domain behaviour information corresponding to aperiodic behaviour.
The method of any one of claims 11 to 15, wherein the first time domain behaviour is aperiodic and the second time domain behaviour is periodic or semi-persistent.
The method of any one of claims 11 to 16, further comprising:

receiving a DCI to schedule a physical uplink shared channel (PUSCH) transmission, the DCI comprising an SRS resource indicator indicating one of the SRS resources from the first SRS resource set or the second SRS resource set to be used for the PUSCH transmission; and

transmitting, by the terminal device, a PUSCH according to the indicated SRS resource.
The method of claim 17, wherein the first SRS resource set and the second SRS resource set are configured for codebook based transmission,

wherein the SRS resource indicator consists of exactly and no more than

bits where N _SRS, 0 is the number SRS resources in the first SRS resource set and N _SRS, 1 is the number of SRS resources in the second SRS resource set.
The method of claim 17, wherein the first SRS resource set and the second SRS resource set are configured for non-codebook based transmission,

wherein the SRS resource indicator consists of exactly and no more than
bits where N _SRS=N _SRS, 0+N _SRS, 1, where N _SRS, 0 is the number of SRS resources in the first SRS resource set and N _SRS, 1 is the number SRS resources in the second SRS resource set.
The method of claim 17, wherein the first SRS resource set and the second SRS resource set are configured for codebook based transmission, and

wherein the SRS resource indicator consists of exactly and no more than
bits where N _SRS, 0 is the number SRS resources in the first SRS resource set or the number of SRS resources in the second SRS resource set.
The method of claim 17, wherein the first SRS resource set and the second SRS resource set are configured for non-codebook based transmission, and

wherein the SRS resource indicator consists of exactly and no more than
bits where N _SRS=N _SRS, 0 where N _SRS, 0 is the number SRS resources in the first SRS resource set or the number of SRS resources in the second SRS resource set.
The method of claim 20 or 21, comprising the terminal device selecting an SRS resource from the SRS resource set having the lowest ID among the first SRS resource set and second SRS resource set for use in transmitting the requested PUSCH transmission.
The method of claim 20 or 21, comprising the terminal device selecting an SRS resource from the SRS resource set having the highest ID among the first SRS resource set and second SRS resource set for use in transmitting the requested PUSCH.
The method of claim 20 or 21, comprising the terminal device selecting an SRS resource for use in transmitting the requested PUSCH from a predetermined one of the first SRS resource set and second SRS resource set.
The method of any one of claims 11 to 24, comprising receiving the first SRS resource set through a first SRS-ResourceSet parameter, and receiving the second SRS resource set through a second SRS-ResourceSet parameter.
The method of claim 25, comprising receiving the first time domain behaviour through a first resourceType parameter in the first SRS-ResourceSet parameter, and receiving the second time domain behaviour through a second resourceType parameter in the second SRS-ResourceSet parameter.
The method of any one of claims 11 to 26, wherein a number of SRS resources in the first SRS resource set is the same as a number of SRS resources in a second SRS resource set.
The method any one of claims 11 to 27, wherein the first SRS resource and the second SRS resource are configured with the same spatial relation information.
A computer-readable medium having computer-executable instructions to cause one or more processors of a computing device to carry out the method of any one of claims 1 to 28.
A terminal device, comprising:

a processor; and

a memory configured to store a computer program capable of being run in the processor,

wherein the processor is configured to run the computer program to perform the steps in the method of any of claims 1 to 28.
A terminal device for transmitting a sounding reference signal (SRS) resource, comprising:

a communication unit to receive SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information; and

a processing unit configured to:

determine which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission; and

control the communication unit to transmit an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour.
The terminal device of claim 31, wherein the communication unit is configured to receive the SRS information through a radio resource control (RRC) parameter.
The terminal device of claim 31 or claim 32, wherein the SRS information comprises an SRS resource set comprising the configuration of the SRS resource, the SRS resource being configured with the first time domain behaviour and the second time domain behaviour.
The terminal device of claim 33, wherein the processing unit is configured to:

determine which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission by determining that one of the first time domain behaviour and the second time domain behaviour is a periodic behaviour, and wherein controlling the communication unit to transmit an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

controlling the communication unit to transmit the SRS resource according to the periodic behaviour.
The terminal device of claim 33 or claim 34, wherein the processing unit is configured to:

determine which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission by determining both: 1) that one of the first time domain behaviour and the second time domain behaviour is semi-persistent and 2) that an activation command has been received, and

wherein controlling the communication unit to transmit an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

controlling the communication unit to transmit the SRS resource according to the semi-persistent behaviour.
The terminal device of claim 35, wherein the activation command is a medium access control (MAC) control element (CE) activation command.
The terminal device of any of claims 33 to 36, wherein the processing unit is configured to:

determine which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission by determining both: 1) that one of the first time domain behaviour and the second time domain behaviour is an aperiodic behaviour, and 2) that a downlink control information (DCI) has been received, and

wherein controlling the communication unit to transmit an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

controlling the communication unit to transmit the SRS resource using the aperiodic behaviour.
The terminal device of any one of claims 31 to 37, wherein the first time domain behaviour is aperiodic and the second time domain behaviour is periodic or semi-persistent.
The terminal device of any one of claims 33 to 38, wherein the communication unit is configured to receive the SRS resource set through an SRS-ResourceSet parameter.
The terminal device of claim 39, wherein the communication unit is configured to receive the first time domain behaviour through a first resourceType parameter in the SRS-ResourceSet parameter, and receive the second time domain behaviour through a second resourceType parameter in the SRS-ResourceSet parameter.
The terminal device of claim 31 or claim 32, wherein the SRS information comprises:

a first SRS resource set comprising a configuration of a first SRS resource with the first time domain behaviour; and

a second SRS resource set comprising a configuration of a second SRS resource with the second time domain behaviour.
The terminal device of claim 41, wherein the processing unit is configured to:

determine which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission by determining that one of the first time domain behaviour and the second time domain behaviour is a periodic behaviour and

wherein controlling the communication unit to transmit an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

controlling the communication unit to transmit, according to the periodic behaviour, the one of the SRS resources with the time domain behaviour information corresponding to periodic behaviour.
The terminal device of claim 41 or claim 42, wherein the processing unit is configured to:

determine which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission by determining both: 1) that one of the first time domain behaviour and the second time domain behaviour is semi-persistent and 2) that an activation command has been received, and

wherein controlling the communication unit to transmit an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

controlling the communication unit to transmit, according to the semi-persistent behaviour, the one of the SRS resources with the time domain behaviour information corresponding to semi-persistent behaviour.
The terminal device of claim 43, wherein the activation command is a MAC CE activation command.
The terminal device of any of claims 41 to 44, wherein the processing unit is configured to:

determine which of the first time domain behaviour and the second time domain behaviour to use for SRS transmission by determining both: 1) that one of the first time domain behaviour and the second time domain behaviour is an aperiodic behaviour, and 2) that a DCI has been received, and

wherein controlling the communication unit to transmit an SRS resource according to the determined one of the first time domain behaviour and the second time domain behaviour, comprises:

controlling the communication unit to transmit, according to the aperiodic behaviour, the one of the SRS resources with the time domain behaviour information corresponding to aperiodic behaviour.
The terminal device of any one of claims 41 to 45, wherein the first time domain behaviour is aperiodic and the second time domain behaviour is periodic or semi-persistent.
The terminal device of any one of claims 41 to 46, wherein:

the communication unit is configured to receive a DCI to schedule a physical uplink shared channel (PUSCH) transmission, the DCI comprising an SRS resource indicator indicating one of the SRS resources from the first SRS resource set or the second SRS resource set to be used for the PUSCH transmission; and

the processing unit is configured to control the communication unit to transmit the PUSCH transmission according to the indicated SRS resource.
The terminal device of claim 47, wherein the first SRS resource set and the second SRS resource set are configured for codebook based transmission,

wherein the SRS resource indicator consists of exactly and no more than

bits where N _SRS, 0 is the number SRS resources in the first SRS resource set and N _SRS, 1 is the number of SRS resources in the second SRS resource set.
The terminal device of claim 47, wherein the first SRS resource set and the second SRS resource set are configured for non-codebook based transmission,

wherein the SRS resource indicator consists of exactly and no more than
bits where N _SRS=N _SRS, 0+N _SRS, 1, where N _SRS, 0 is the number of SRS resources in the first SRS resource set and N _SRS, 1 is the number SRS resources in the second SRS resource set.
The terminal device of claim 47, wherein the first SRS resource set and the second SRS resource set are configured for codebook based transmission, and

wherein the SRS resource indicator consists of exactly and no more than
bits where N _SRS, 0 is the number SRS resources in the first SRS resource set or the number of SRS resources in the second SRS resource set.
The terminal device of claim 47, wherein the first SRS resource set and the second SRS resource set are configured for non-codebook based transmission, and

wherein the SRS resource indicator consists of exactly and no more than
bits where N _SRS=N _SRS, 0 where N _SRS, 0 is the number SRS resources in the first SRS resource set or the number of SRS resources in the second SRS resource set.
The terminal device of claim 50 or 51, wherein the processing unit is configured to select an SRS resource from the SRS resource set having the lowest ID among the first SRS resource set and second SRS resource set for use in transmitting the requested PUSCH transmission.
The terminal device of claim 50 or 51, wherein the processing unit is configured to selected an SRS resource from the SRS resource set having the highest ID among the first SRS resource set and second SRS resource set for use in transmitting the requested PUSCH.
The terminal device of claim 50 or 51, wherein the processing unit is configured to select an SRS resource for use in transmitting the requested PUSCH from a predetermined one of the first SRS resource set and second SRS resource set.
The terminal device of any one of claims 41 to 54, wherein the communication unit is configured to receive the first SRS resource set through a first SRS-ResourceSet parameter, and to receive the second SRS resource set through a second SRS-ResourceSet parameter.
The terminal device of claim 55, wherein the communication unit is configured to receive the first time domain behaviour through a first resourceType parameter in the first SRS-ResourceSet parameter, and to receive the second time domain behaviour through a second resourceType parameter in the second SRS-ResourceSet parameter.
The terminal device of any one of claims 41 to 56, wherein a number of SRS resources in the first SRS resource set is the same as a number of SRS resources in a second SRS resource set.
The terminal device any one of claims 41 to 57, wherein the first SRS resource and the second SRS resource are configured with the same spatial relation information.
A method for initiating transmission by a terminal device of a sounding reference signal (SRS) resource, the method comprising:

transmitting, by a network device, SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information; and

receiving, at the network device, an SRS resource according to one of the first time domain behaviour and the second time domain behaviour.
The method of claim 59, wherein the SRS information comprises an SRS resource set comprising the configuration of the SRS resource, the SRS resource being configured with the first time domain behaviour and the second time domain behaviour.
The method of claim 60, further comprising transmitting, by the network device, an activation command to activate a semi-persistent SRS transmission,

wherein one of the first time domain behaviour and the second time domain behaviour is semi-persistent, and

wherein receiving the SRS resource comprises receiving the SRS resource according to the semi-persistent behaviour.
The method of any of claims 60 to 61, further comprising transmitting, by the network device, a downlink control information (DCI) to activate an aperiodic SRS transmission,

wherein one of the first time domain behaviour and the second time domain behaviour is an aperiodic behaviour, and

wherein receiving the SRS resource comprises receiving the SRS resource according to the aperiodic behaviour.
The method of claim 59, wherein the SRS information comprises:

a first SRS resource set comprising a configuration of a first SRS resource with the first time domain behaviour; and

a second SRS resource set comprising a configuration of a second SRS resource with the second time domain behaviour.
The method of claim 63, further comprising transmitting, by the network device, an activation command to activate a semi-persistent SRS transmission,

wherein one of the first time domain behaviour and the second time domain behaviour is semi-persistent, and

wherein receiving the SRS resource comprises receiving the one of the SRS resources with the time domain behaviour information corresponding to semi-persistent behaviour.
The method of any of claims 63 to 64, further comprising transmitting, by the network device, a downlink control information (DCI) to activate an aperiodic SRS transmission,

wherein one of the first time domain behaviour and the second time domain behaviour is an aperiodic behaviour, and

wherein receiving the SRS resource comprises receiving the one of the SRS resources with the time domain behaviour information corresponding to the aperiodic behaviour.
A computer-readable medium having computer-executable instructions to cause one or more processors of a computing device to carry out the method of any one of claims 59 to 65.
A network device, comprising:

a processor; and

a memory configured to store a computer program capable of being run in the processor,

wherein the processor is configured to run the computer program to perform the steps in the method of any of claims 59 to 65.
A network device for initiating transmission by a terminal device of a sounding reference signal (SRS) resource, the network device comprising:

a communication unit; and

a processing unit to control the communication unit to transmit SRS information for either codebook or non-codebook based transmission, the SRS information comprising: a configuration of at least one SRS resource, first time domain behaviour information, and second time domain behaviour information, wherein the first time domain behaviour information is different to the second time domain behaviour information,

wherein the communication unit is configured to receive an SRS resource according to one of the first time domain behaviour and the second time domain behaviour.
The network device of 68, wherein the SRS information comprises an SRS resource set comprising the configuration of the SRS resource, the SRS resource being configured with the first time domain behaviour and the second time domain behaviour.
The network device of claim 69, wherein the processing unit is configured to control the communication unit to transmit an activation command to activate a semi-persistent SRS transmission,

wherein one of the first time domain behaviour and the second time domain behaviour is semi-persistent, and

wherein the communication unit is configured to receive the SRS according to the semi-persistent behaviour.
The network device of any of claims 69 to 70, wherein the processing unit is configured to control the communication unit to transmit a downlink control information (DCI) to activate an aperiodic SRS transmission,

wherein one of the first time domain behaviour and the second time domain behaviour is an aperiodic behaviour, and

wherein the communication unit is configured to receive the SRS resource according to the aperiodic behaviour.
The network device of claim 68, wherein the SRS information comprises:

a first SRS resource set comprising a configuration of a first SRS resource with the first time domain behaviour; and

a second SRS resource set comprising a configuration of a second SRS resource with the second time domain behaviour.
The network device of claim 72, wherein the processing unit is configured to control the communication unit to transmit an activation command to activate a semi-persistent SRS transmission,

wherein one of the first time domain behaviour and the second time domain behaviour is semi-persistent, and

wherein the communication unit is configured to receive the one of the SRS resources with the time domain behaviour information corresponding to semi-persistent behaviour.
The network device of any of claims 72 to 73, wherein the processing unit is configured to control the communication unit to transmit a downlink control information (DCI) to activate an aperiodic SRS transmission,

wherein one of the first time domain behaviour and the second time domain behaviour is an aperiodic behaviour, and

wherein the communication unit is configured to receive the one of the SRS resources with the time domain behaviour information corresponding to the aperiodic behaviour.