WO2021248449A1

WO2021248449A1 - Methods and apparatus for configuring csi-rs resource for srs resource set

Info

Publication number: WO2021248449A1
Application number: PCT/CN2020/095805
Authority: WO
Inventors: Wei Ling; Chenxi Zhu; Bingchao LIU; Yi Zhang
Original assignee: Lenovo Beijing Ltd
Current assignee: Lenovo Beijing Ltd
Priority date: 2020-06-12
Filing date: 2020-06-12
Publication date: 2021-12-16
Anticipated expiration: 2022-12-12

Abstract

Embodiments of the present disclosure relate to methods and apparatus for configuring a CSI-RS resource for an SRS resource set. According to an embodiment of the present disclosure, a method for wireless communication includes: receiving a physical downlink shared channel transmission carrying an MAC CE which indicates an SRS resource set and a CSI-RS resource associated with the SRS resource set, wherein the SRS resource set is configured as non-codebook; and determining a precoder for the indicated SRS resource set based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE.

Description

METHODS AND APPARATUS FOR CONFIGURING CSI-RS RESOURCE FOR SRS RESOURCE SET

TECHNICAL FIELD

Embodiments of the present disclosure are related to wireless communication technologies, and more particularly, related to methods and apparatuses for configuring a channel state information reference signal (CSI-RS) resource for a sounding reference signal (SRS) resource set configured with non-codebook usage.

BACKGROUND

A communication system, such as a 3rd Generation Partnership Project (3GPP) New Radio (NR) system, may support both codebook based and non-codebook based physical uplink shared channel (PUSCH) transmissions. For a codebook based PUSCH transmission of a user equipment (UE) , a network (or a base station) assigns the UE a precoder for the PUSCH transmission as part of an uplink scheduling grant. For a non-codebook based PUSCH transmission of a UE, the UE determines a precoder for the PUSCH transmission based on measurement (s) of downlink reference signal (s) such as CSI-RS. Non-codebook based precoding is based on an assumption of channel reciprocity, that is, the UE can acquire detailed knowledge of an uplink channel based on downlink measurements.

A non-codebook based PUSCH transmission of a UE is associated with an SRS resource set of the UE configured with a usage parameter as "non-codebook" (herein also referred to as an SRS resource set configured with non-codebook usage or configured as non-codebook) . An associated CSI-RS resource can be configured for the SRS resource set configured with non-codebook usage. The associated CSI-RS resource is normally a non-zero power (NZP) CSI-RS resource. The UE can measure the associated CSI-RS resource and determine a precoder for the SRS resource set configured with non-codebook usage based on the measurement of the associated CSI-RS resource.

In 3GPP NR Release 15, the associated CSI-RS resource is configured or updated by higher layer signaling such as radio resource control (RRC) signaling. The overhead and latency of configuring or updating the associated CSI-RS resource for an SRS resource set configured with non-codebook usage is high, especially for an aperiodic SRS resource set. It is desired to develop a method to configure or update the associated CSI-RS resource for an SRS resource set configured with non-codebook usage with reduced overhead and latency.

SUMMARY OF THE DISCLOSURE

According to an embodiment of the present disclosure, a method for wireless communication may include: receiving a PDSCH transmission carrying a medium access control layer control element (MAC CE) which indicates an SRS resource set and a CSI-RS resource associated with the SRS resource set, wherein the SRS resource set is configured as non-codebook; and determining a precoder for the indicated SRS resource set based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE.

According to another embodiment of the present disclosure, a method for wireless communication may include: transmitting a PDSCH transmission carrying a MAC CE which indicates an SRS resource set and a CSI-RS resource associated with the SRS resource set, wherein the SRS resource set is configured as non-codebook; and receiving an SRS resource transmission of the SRS resource set which is precoded based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE.

According to yet another embodiment of the present disclosure, an apparatus may include: at least one non-transitory computer-readable medium having stored thereon computer executable instructions; at least one receiving circuitry; at least one transmitting circuitry; and at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry. The computer executable instructions may cause the at least processor to implement a method according to any embodiment of the present disclosure.

The details of one or more examples are set forth in the accompanying drawings and the description below. Other features, objects, and advantages will be apparent from the description and drawings, and from the claims.

BRIEF DESCRIPTION OF THE DRAWINGS

In order to describe the manner in which advantages and features of the present disclosure can be obtained, a description of the present disclosure is rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. These drawings depict only exemplary embodiments of the present disclosure and are not therefore intended to limit the scope of the present disclosure.

FIG. 1 illustrates an architectural diagram of a communication system;

FIG. 2 illustrates an exemplary procedure for a non-codebook based PUSCH transmission;

FIG. 3 illustrates an exemplary MAC CE used to configure or update an associated CSI-RS resource for an SRS resource set configured with non-codebook usage according to some embodiments of the present disclosure;

FIG. 4 illustrates an exemplary flow chart of a method for configuring or updating an associated CSI-RS resource for an SRS resource set configured with non-codebook usage according to some embodiments of the present disclosure;

FIG. 5 illustrates an exemplary flow chart of another method for configuring or updating an associated CSI-RS resource for an SRS resource set configured with non-codebook usage according to some embodiments of the present disclosure;

FIG. 6 illustrates an exemplary block diagram of an apparatus according to some embodiments of the present disclosure; and

FIG. 7 illustrates an exemplary block diagram of another apparatus according to some embodiments of the present disclosure.

DETAILED DESCRIPTION

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

In the following description, numerous specific details are provided, such as examples of programming, software modules, network transactions, database structures, hardware modules, hardware circuits, etc., to provide a thorough understanding of embodiments. One skilled in the relevant art will recognize, however, that embodiments may be practiced without one or more of the specific details, or with other methods, components, materials, and so forth. In other instances, well-known structures, materials, or operations are not shown or described in detail to avoid obscuring aspects of an embodiment.

Reference will now be made in detail to some embodiments of the present disclosure, examples of which are illustrated in the accompanying drawings. To facilitate understanding, embodiments are provided under specific network architecture and new service scenarios, such as 3GPP 5G, 3GPP Long Term Evolution (LTE) and so on. Persons skilled in the art know very well that, with the development of network architecture and new service scenarios, the embodiments in the present disclosure are also applicable to similar technical problems; and moreover, the terminologies recited in the present disclosure may change, which should not affect the principle of the present disclosure.

FIG. 1 illustrates an architectural diagram of a wireless communication system 100. As shown in FIG. 1, the wireless communication system 100 includes a base station (BS) 102 and a UE 104. Although merely, for simplicity, one BS is illustrated in FIG. 1, it is contemplated that the wireless communication system 100 may include more BSs in some other embodiments of the present disclosure. Similarly, although merely one UE is illustrated in FIG. 1 for simplicity, it is contemplated that the wireless communication system 100 may include more UEs in some other embodiments of the present disclosure.

The wireless communication system 100 is compatible with any type of network that is capable of sending and receiving wireless communication signals. For example, the wireless communication system 100 is compatible with a wireless communication network, a cellular telephone network, a time division multiple access (TDMA) -based network, a code division multiple access (CDMA) -based network, an orthogonal frequency division multiple access (OFDMA) -based network, an LTE network, a 3GPP-based network, a 3GPP 5G network, a satellite communications network, a high altitude platform network, and/or other communications networks.

The UE 104 may include computing devices, such as desktop computers, laptop computers, personal digital assistants (PDAs) , tablet computers, smart televisions (e.g., televisions connected to the Internet) , set-top boxes, game consoles, security systems (including security cameras) , vehicle on-board computers, network devices (e.g., routers, switches, and modems) , or the like. According to an embodiment of the present disclosure, the UE 104 may include a portable wireless communication device, a smart phone, a cellular telephone, a flip phone, a device having a subscriber identity module, a personal computer, a selective call receiver, or any other device that is capable of sending and receiving communication signals on a wireless network. In some embodiments, the UE 104 may include wearable devices, such as smart watches, fitness bands, optical head-mounted displays, or the like. Moreover, the UE 104 may be referred to as a subscriber unit, a mobile, a mobile station, a user, a terminal, a mobile terminal, a wireless terminal, a fixed terminal, a subscriber station, a user terminal, or a device, or described using other terminology used in the art.

The BS 102 may also be referred to as an access point, an access terminal, a base, a macro cell, a node-B, an enhanced node B (eNB) , a gNB, a home node-B, a relay node, or a device, or described using other terminology used in the art. The BS 102 is generally part of a radio access network that may include a controller communicably coupled to the BS 102. The BS 102 may be configured to transmit and/or receive wireless signals within a particular geographic region, which may be referred to as a cell (not shown in FIG. 1) . It should be understood that the term "base station" may refer to a single physical transmission-reception point (TRP) or to multiple physical TRPs that may or may not be co-located.

A communication link through which the UE 104 can send signals to the BS 102 is called an uplink channel (e.g., a reverse traffic channel, a reverse control channel, an access channel, etc. ) . A communication link through which the BS 102 can send signals to the UE 104 is called a downlink channel (e.g., a paging channel, a control channel, a broadcast channel, a forward traffic channel, etc. ) . The UE 104 can send a non-codebook based PUSCH transmission to the BS 102.

FIG. 2 illustrates an exemplary procedure for a non-codebook based PUSCH transmission. The BS and UE involved in the procedure illustrated in FIG. 2 can be any BS (e.g., BS 102) and any UE (e.g., UE 104) described herein.

As shown in FIG. 2, the BS may transmit a CSI-RS to the UE (202) . The CSI-RS can be transmitted using the associated CSI-RS resource configured for an SRS resource set of the UE which is configured with non-codebook usage and associated with the non-codebook based PUSCH transmission of the UE. The SRS resource set may include one or more SRS resources. For example, in the standard document TS 38.214, only one NZP CSI-RS resource can be configured for an SRS resource set configured with non-codebook usage, only one SRS resource set can be configured with non-codebook usage for a UE, and the maximum number of SRS resources included in the SRS resource set configured with non-codebook usage is specified to be 4. The maximum number of SRS resources which can be configured to the UE for simultaneous transmission in the same symbol and the maximum number of SRS resources are capabilities of the UE, which may be reported to the BS. The SRS resources transmitted simultaneously may occupy the same resource blocks (RBs) . Each SRS resource is configured with only one antenna port, that is, each SRS resource is transmitted via only one antenna port.

The UE may measure the associated CSI-RS resource configured for the SRS resource set which is configured with non-codebook usage, and calculate a precoder for the SRS resource set based on (or based at least in part on) the measurement of the associated CSI-RS resource (204) . The precoder may represent weighting of each SRS resource in the SRS resource set that is applied in an SRS resource transmission. Then, the UE may precode the SRS resource (s) in the SRS resource set using the calculated precoder, and transmit the precoded SRS resource (s) to the BS (206) .

The BS may select one or more SRS resources from the received SRS resource (s) for the non-codebook based PUSCH transmission (208) . The number of the selected one or more SRS resources represents a transmission rank configured for the PUSCH transmission of the UE, i.e., the number of layers to be transmitted on the uplink channel. Then, the BS may transmit downlink control information (DCI) for scheduling the PUSCH transmission to the UE (210) . For example, the DCI may be DCI format 0_0, DCI format 0_1, or semi-statically configured. The DCI may include a SRS resource indicator (SRI) which indicates the selected one or more SRS resources for the PUSCH transmission. The SRI is associated with the most recent transmission of SRS resource (s) identified by the SRI, where the SRS resource transmission is prior to the physical downlink control channel (PDCCH) carrying the SRI. In some aspects, the DCI may also indicate demodulation reference signal (DM-RS) port (s) for the PUSCH transmission.

After receiving the DCI for scheduling the PUSCH transmission, the UE may send the PUSCH transmission using the same antenna port (s) as the one or more SRS resources indicated by the SRI included in the DCI (212) .

The SRS resource set configured with non-codebook usage can be configured as periodic, semi-persistent, or aperiodic. As stated above, in 3GPP NR Release 15, the CSI-RS resource associated with the SRS resource set configured with non-codebook usage is configured or updated by higher layer signaling such as RRC signaling. For example, when the SRS resource set is configured as periodic, semi-persistent or aperiodic, the CSI-RS resource associated with the SRS resource set can be indicated via a higher layer parameter associatedCSI-RS in SRS-ResourceSet configured by RRC signaling. A UE is not expected to update the SRS precoding information if the gap from the last symbol of the reception of the associated CSI-RS resource and the first symbol of the aperiodic SRS resource transmission is less than 42 orthogonal frequency division multiplexing (OFDM) symbols. Configuring or updating the associated CSI-RS resource for an SRS resource set by RRC signaling may result in high overhead and latency, especially for an aperiodic SRS resource set configured with non-codebook usage.

3GPP NR Release 16 supports MAC CE based spatial relation information update for an aperiodic SRS resource per resource level. That is, spatial relation information for an SRS resource can be configured or updated by a MAC CE. The spatial relation information for an SRS resource is used to indicate a transmission beam for the SRS resource. MAC CE based spatial relation information configuration or update has lower latency and lower overhead compared with RRC reconfiguration.

For a non-codebook based PUSCH transmission, a UE does not expect to be configured with both the associated CSI-RS resource for a SRS resource set and the spatial relation information for each SRS resource in the SRS resource set, because the UE does not expect to be configured with different spatial relation information for SRS resources within the same SRS resource set. Since the associated CSI-RS resource is configured or updated per resource set level while the spatial relation information is configured or updated per resource level, configuring or updating the associated CSI-RS resource can be more efficient than configuring or updating the spatial relation information. Moreover, configuring or updating the associated CSI-RS resource by a MAC CE transmitted from a BS to a UE can have lower latency and lower overhead than configuring or updating the associated CSI-RS resource by RRC signaling.

FIG. 3 illustrates an exemplary MAC CE used to configure or update the associated CSI-RS resource for an SRS resource set configured with non-codebook usage according to some embodiments of the present disclosure. The MAC CE may indicate an SRS resource set configured with non-codebook usage and a CSI-RS resource associated with the SRS resource set. Although the MAC CE illustrated in FIG. 3 includes particular fields of particular sizes arranged in a particular order, it is contemplated that FIG. 3 is provided for illustration, not for limitation; the MAC CE within the scope of the present disclosure may include other fields, and other sizes and/or orders of the fields in the MAC CE are not excluded.

The MAC CE illustrated in FIG. 3 includes 3 rows and each row includes 8 bits (also referred to as an octet) . The fields marked as "R" represent reserved bits. In some embodiments of the present disclosure, the reserved bit can be set to "0. "

Field 302 indicates an identity of a serving cell which contains the SRS resource set indicated by the MAC CE. In an embodiment of the present disclosure, the size of the field 302 is 5 bits. Field 304 indicates an identity of an uplink bandwidth part (BWP) which contains the indicated SRS resource set. In an embodiment of the present disclosure, the size of the field 304 is 2 bits.

Field 306 is an indicator which indicates whether the MAC CE applies to a normal uplink (NUL) carrier configuration or a supplementary uplink (SUL) carrier configuration. In an embodiment of the present disclosure, the size of the field 306 is 1 bit. The field 306 is set to "1" to indicate that the MAC CE applies to the SUL carrier configuration, and it is set to "0" to indicate that the MAC CE applies to the NUL carrier configuration. Alternatively, the field 306 is set to "0" to indicate that the MAC CE applies to the SUL carrier configuration, and it is set to "1" to indicate that the MAC CE applies to the NUL carrier configuration.

Field 308 indicates an identity of the indicated SRS resource set. In an embodiment of the present disclosure, the size of the field 308 is 4 bits. Field 310 indicates an identity of the indicated CSI-RS resource associated with the indicated SRS resource set. In an embodiment of the present disclosure, the size of the field 310 is 7 bits. It is assumed that the serving cell and BWP which contain the indicated CSI-RS resource are the same as those containing the indicated SRS resource set, and thus it is not needed to indicate the serving cell and BWP which contain the indicated CSI-RS resource in the MAC CE. In other embodiments of the present disclosure, the MAC CE may include fields indicating the serving cell and/or BWP which contain the indicated CSI-RS resource.

FIG. 4 illustrates an exemplary flow chart of a method 400 for configuring or updating an associated CSI-RS resource for an SRS resource set configured with non-codebook usage according to some embodiments of the present disclosure. Although described with respect to a UE, it should be understood that other devices may be configured to perform a method similar to that of FIG. 4.

As shown in FIG. 4, in step 402, a UE (e.g., UE 104) may receive a PDSCH transmission carrying a MAC CE which indicates an SRS resource set and a CSI-RS resource associated with the SRS resource set, wherein the SRS resource set is configured as non-codebook. According to an embodiment of the present disclosure, the MAC CE may have a structure as illustrated in FIG. 3. The SRS resource set may be configured as periodic, semi-persistent, or aperiodic.

In step 404, the UE may determine a precoder for the indicated SRS resource set based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE. After that, the UE may proceed to perform subsequent steps of a procedure for a non-codebook based PUSCH transmission as illustrated in FIG. 2.

According to some embodiments of the present disclosure, the UE may transmit an acknowledgement message in response to the PDSCH transmission carrying the MAC CE which is received in step 402. The CSI-RS resource indicated in the MAC CE is applied at least a predetermined time interval after transmission of the acknowledgement message. That is, the determination of the precoder should be performed at least a predetermined time interval after transmission of the acknowledgement message. In an embodiment of the present disclosure, the predetermined time interval may equal a length of 3 subframes, e.g., 3 milliseconds.

FIG. 5 illustrates an exemplary flow chart of a method 500 for configuring or updating an associated CSI-RS resource for an SRS resource set configured with non-codebook usage according to some embodiments of the present disclosure. Although described with respect to a BS, it should be understood that other devices may be configured to perform a method similar to that of FIG. 5.

As shown in FIG. 5, in step 502, a BS (e.g., BS 102) may transmit a PDSCH transmission carrying a MAC CE which indicates an SRS resource set and a CSI-RS resource associated with the SRS resource set, wherein the SRS resource set is configured as non-codebook. According to an embodiment of the present disclosure, the MAC CE may have a structure as illustrated in FIG. 3. The SRS resource set may be configured as periodic, semi-persistent, or aperiodic.

In step 504, the BS may receive an SRS resource transmission of the SRS resource set which is precoded based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE. After that, the BS may proceed to perform subsequent steps of a procedure for a non-codebook based PUSCH transmission as illustrated in FIG. 2.

According to some embodiments of the present disclosure, the BS may receive an acknowledgement message in response to the PDSCH transmission carrying the MAC CE which is transmitted in step 502. The CSI-RS resource indicated in the MAC CE is applied at least a predetermined time interval after transmission of the acknowledgement message. Thus, the precoded SRS resource transmission is received at least a predetermined time interval after transmission of the acknowledgement message. In an embodiment of the present disclosure, the predetermined time interval may equal a length of 3 subframes, e.g., 3 milliseconds.

FIG. 6 illustrates an exemplary block diagram of an apparatus 600 according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the apparatus 600 may be a UE (e.g., any UE described herein) or other devices having similar functionalities, which can at least perform any of the methods illustrated in FIGS. 2 and 4.

As shown in FIG. 6, the apparatus 600 may include at least one receiving circuitry 602, at least one transmitting circuitry 604, at least one non-transitory computer-readable medium 606, and at least one processor 608 coupled to the at least one receiving circuitry 602, the at least one transmitting circuitry 604, the at least one non-transitory computer-readable medium 606. While shown to be coupled to each other via the at least one processor 608 in the example of FIG. 6, the at least one receiving circuitry 602, the at least one transmitting circuitry 604, the at least one non-transitory computer-readable medium 606, and the at least one processor 608 may be coupled to one another in various arrangements. For example, the at least one receiving circuitry 602, the at least one transmitting circuitry 604, the at least one non-transitory computer-readable medium 606, and the at least one processor 608 may be coupled to each other via one or more local buses (not shown for simplicity) .

Although in FIG. 6, elements such as receiving circuitry 602, transmitting circuitry 604, non-transitory computer-readable medium 606, and processor 608 are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the at least one receiving circuitry 602 and the at least one transmitting circuitry 604 are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, the apparatus 600 may further include an input device, a memory, and/or other components.

In some embodiments of the present disclosure, the at least one non-transitory computer-readable medium 606 may have stored thereon computer-executable instructions which are programmed to cause the at least one processor 608 to implement the steps of the methods, for example as described in view of FIGS. 2 and 4, with the at least one receiving circuitry 602 and the at least one transmitting circuitry 604. For example, when executed, the instructions may cause the at least one processor 608 to receive a PDSCH transmission carrying a MAC CE which indicates an SRS resource set and a CSI-RS resource associated with the SRS resource set with the at least one receiving circuitry 602, wherein the SRS resource set is configured as non-codebook. The instructions may further cause the at least one processor 608 to determine a precoder for the indicated SRS resource set based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE. In some embodiments of the present disclosure, the instructions may further cause the at least one processor 608 to transmit an acknowledgement message in response to the PDSCH transmission with the at least one transmitting circuitry 604.

FIG. 7 illustrates an exemplary block diagram of an apparatus 700 according to some embodiments of the present disclosure. In some embodiments of the present disclosure, the apparatus 700 may be a BS (e.g., any BS described herein) or other devices having similar functionalities, which can at least perform any of the methods illustrated in FIGS. 2 and 5.

As shown in FIG. 7, the apparatus 700 may include at least one receiving circuitry 702, at least one transmitting circuitry 704, at least one non-transitory computer-readable medium 706, and at least one processor 708 coupled to the at least one receiving circuitry 702, the at least one transmitting circuitry 704, the at least one non-transitory computer-readable medium 706. While shown to be coupled to each other via the at least one processor 708 in the example of FIG. 7, the at least one receiving circuitry 702, the at least one transmitting circuitry 704, the at least one non-transitory computer-readable medium 706, and the at least one processor 708 may be coupled to one another in various arrangements. For example, the at least one receiving circuitry 702, the at least one transmitting circuitry 704, the at least one non-transitory computer-readable medium 706, and the at least one processor 708 may be coupled to each other via one or more local buses (not shown for simplicity) .

Although in FIG. 7, elements such as receiving circuitry 702, transmitting circuitry 704, non-transitory computer-readable medium 706, and processor 708 are described in the singular, the plural is contemplated unless limitation to the singular is explicitly stated. In some embodiments of the present disclosure, the at least one receiving circuitry 702 and the at least one transmitting circuitry 704 are combined into a single device, such as a transceiver. In certain embodiments of the present disclosure, the apparatus 700 may further include a memory and/or other components.

In some embodiments of the present disclosure, the at least one non-transitory computer-readable medium 706 may have stored thereon computer-executable instructions which are programmed to cause the at least one processor 708 to implement the steps of the methods described herein with the at least one receiving circuitry 702 and the at least one transmitting circuitry 704. For example, when executed, the instructions may cause the at least one processor 708 to transmit a PDSCH transmission carrying a MAC CE which indicates an SRS resource set and a CSI-RS resource associated with the SRS resource set with the at least one transmitting circuitry 704, wherein the SRS resource set is configured as non-codebook. The instructions may further cause the at least one processor 708 to receive an SRS resource transmission of the SRS resource set which is precoded based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE with the at least one receiving circuitry 702. In some embodiments of the present disclosure, the instructions may further cause the at least one processor 708 to receive an acknowledgement message in response to the PDSCH transmission with the at least one receiving circuitry 702.

As will be appreciated by one skilled in the art, aspects of the embodiments may be embodied as a system, apparatus, method, or a program product. Accordingly, embodiments may take the form of an all-hardware embodiment, an all-software embodiment (including firmware, resident software, micro-code, etc. ) or an embodiment combining software and hardware aspects.

For example, the disclosed embodiments may be implemented as a hardware circuit comprising custom very-large-scale integration (VLSI) circuits or gate arrays, off-the-shelf semiconductors such as logic chips, transistors, or other discrete components. The disclosed embodiments may also be implemented in programmable hardware devices such as field programmable gate arrays, programmable array logic, programmable logic devices, or the like. As another example, the disclosed embodiments may include one or more physical or logical blocks of executable code which may, for instance, be organized as an object, procedure, or function.

Furthermore, embodiments may take the form of a program product embodied in one or more computer readable storage devices storing machine readable code, computer readable code, or program code. The storage devices may be tangible, non-transitory, or non-transmission. The storage devices may not embody signals. In a certain embodiment, the storage devices only employ signals for accessing code.

Any combination of one or more computer readable medium may be utilized. The computer readable medium may be a computer readable storage medium. The computer readable storage medium may be a storage device storing the code. The storage device may be, for example, but is not limited to being, an electronic, magnetic, optical, electromagnetic, infrared, holographic, micromechanical, or semiconductor system, apparatus, or device, or any suitable combination of the foregoing.

A non-exhaustive list of more specific examples of the storage device may include the following: an electrical connection having one or more wires, a portable computer diskette, a hard disk, a random-access memory (RAM) , a read-only memory (ROM) , an erasable programmable read-only memory (EPROM or Flash memory) , a portable compact disc read-only memory (CD-ROM) , an optical storage device, a magnetic storage device, or any suitable combination of the foregoing. In the context of this document, a computer readable storage medium may be any tangible medium that can contain or store a program for use by or in connection with an instruction execution system, apparatus, or device.

Furthermore, the described features, structures, or characteristics of the embodiments may be combined in any suitable manner. While this disclosure has been described with specific embodiments thereof, it is evident that many alternatives, modifications, and variations may be apparent to those skilled in the art. For example, various components of the embodiments may be interchanged, added, or substituted in the other embodiments. Also, all of the elements of each figure are not necessary for operation of the disclosed embodiments. For example, those having ordinary skills in the art would be enabled to make and use the teachings of the disclosure by simply employing the elements of the independent claims. Accordingly, embodiments of the disclosure as set forth herein are intended to be illustrative, not limiting. Various changes may be made without departing from the spirit and scope of the disclosure.

Reference throughout this specification to "one embodiment, " "an embodiment, " or similar language means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. Thus, appearances of the phrases "in one embodiment, " "in an embodiment, " and similar language throughout this specification may, but do not necessarily, all refer to the same embodiment, but mean "one or more but not all embodiments" unless expressly specified otherwise. In this document, the terms "includes, " "including, " or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that includes a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus. An element proceeded by "a, " "an, " or the like does not, without more constraints, preclude the existence of additional identical elements in the process, method, article, or apparatus that includes the element. Also, the term "another" is defined as at least a second or more. The term "having" and the like, as used herein, are defined as "including. "

Claims

A method for wireless communication, comprising:

receiving a physical downlink shared channel (PDSCH) transmission carrying a medium access control layer control element (MAC CE) which indicates a sounding reference signal (SRS) resource set and a channel state information reference signal (CSI-RS) resource associated with the SRS resource set, wherein the SRS resource set is configured as non-codebook; and

determining a precoder for the indicated SRS resource set based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE.
The method of claim 1, wherein the SRS resource set is configured as aperiodic.
The method of claim 1, wherein the SRS resource set is configured as semi-persistent.
The method of claim 1, wherein the SRS resource set is configured as periodic.
The method of claim 1, wherein the MAC CE comprises an identity of the indicated SRS resource set and an identity of the indicated CSI-RS resource.
The method of claim 5, wherein the MAC CE further comprises an identity of a serving cell which contains the indicated SRS resource set.
The method of claim 5, wherein the MAC CE further comprises an identity of an uplink bandwidth part which contains the indicated SRS resource set.
The method of claim 5, wherein the MAC CE further comprises an indicator which indicates whether the MAC CE applies to a normal uplink carrier configuration or a supplementary uplink carrier configuration.
The method of claim 1, further comprising transmitting an acknowledgement message in response to the PDSCH transmission.
The method of claim 9, wherein the precoder is determined at least a predetermined time interval after transmission of the acknowledgement message.
The method of claim 10, wherein the predetermined time interval is 3 milliseconds.
A method for wireless communication, comprising:

transmitting a physical downlink shared channel (PDSCH) transmission carrying a medium access control layer control element (MAC CE) which indicates a sounding reference signal (SRS) resource set and a channel state information reference signal (CSI-RS) resource associated with the SRS resource set, wherein the SRS resource set is configured as non-codebook; and

receiving an SRS resource transmission of the SRS resource set which is precoded based at least in part on a measurement of the CSI-RS resource indicated in the MAC CE.
The method of claim 12, wherein the SRS resource set is configured as aperiodic.
The method of claim 12, wherein the SRS resource set is configured as semi-persistent.
The method of claim 12, wherein the SRS resource set is configured as periodic.
The method of claim 12, wherein the MAC CE comprises an identity of the indicated SRS resource set and an identity of the indicated CSI-RS resource.
The method of claim 16, wherein the MAC CE further comprises an identity of a serving cell which contains the indicated SRS resource set.
The method of claim 16, wherein the MAC CE further comprises an identity of an uplink bandwidth part which contains the indicated SRS resource set.
The method of claim 16, wherein the MAC CE further comprises an indicator which indicates whether the MAC CE applies to a normal uplink carrier configuration or a supplementary uplink carrier configuration.
The method of claim 12, further comprising receiving an acknowledgement message in response to the PDSCH transmission.
The method of claim 20, wherein the precoded SRS resource transmission is received at least a predetermined time interval after transmission of the acknowledgement message.
The method of claim 21, wherein the predetermined time interval is 3 milliseconds.
An apparatus, comprising:

at least one non-transitory computer-readable medium having stored thereon computer-executable instructions;

at least one receiving circuitry;

at least one transmitting circuitry; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry,

wherein the computer-executable instructions cause the at least one processor to implement the method according to any of claims 1-11.
An apparatus, comprising:

at least one non-transitory computer-readable medium having stored thereon computer-executable instructions;

at least one receiving circuitry;

at least one transmitting circuitry; and

at least one processor coupled to the at least one non-transitory computer-readable medium, the at least one receiving circuitry and the at least one transmitting circuitry,

wherein the computer-executable instructions cause the at least one processor to implement the method according to any of claims 12-22.