Method and apparatus for obtaining channel state information

Abstract

The present disclosure relates to a method and apparatus for channel state information (CSI) acquisition using downlink (DL) and uplink (UL) reference signals (RS). A user equipment (UE) operating in a wireless communication system is provided. The UE includes a transceiver and a processor. The processor is configured to: receive configuration information about a non-zero power channel state information reference signal (CSI-RS) resource associated with an aperiodic sounding reference signal (SRS) from a base station, receive downlink control information including aperiodic SRS trigger information from the base station, receive non-zero power CSI-RS associated with the non-zero power CSI-RS resource from the base station, wherein the non-zero power CSI-RS resource is identified based on the aperiodic SRS trigger information, identify an uplink precoder for the aperiodic SRS based on the received non-zero power CSI-RS, and transmit the aperiodic SRS to the base station, wherein when the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS trigger information and the non-zero power CSI-RS are received in the same time slot.

Description

[0001] This application is a divisional application of the application with the invention name "Method and Apparatus for Channel State Information (CSI) Acquisition Using DL and UL Reference Signals" having the application date of March 23, 2018 and the application number of 201880022228.7. Technical Field

[0002] The present disclosure generally relates to methods enabling simultaneous use of downlink (DL) and uplink (UL) reference signals (RS), and more particularly to CSI acquisition using DL and UL signals. Background Art

[0003] To meet the demand for increased wireless data traffic since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "beyond 4G networks" or "post-LTE systems". The 5G communication system is considered to be implemented in a higher frequency (millimeter wave) band, such as the 60 GHz band, in order to achieve higher data rates. To reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large antenna technologies are discussed in 5G communication systems. In addition, in 5G communication systems, system network improvements are being developed based on advanced small cells, cloud radio access network (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multi-point (CoMP), receiver interference cancellation, etc. In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superimposed coding (SWSC) as advanced coding modulation (ACM), and filter bank multi-carrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced access technologies have been developed.

[0004] The Internet, as a human - centric connectivity network in which humans generate and consume information, is now evolving into the Internet of Things (IoT), where distributed entities such as things exchange and process information without human intervention. The Internet of Everything (IoE) has emerged as a combination of IoT technologies and big - data processing technologies through connections to cloud servers. Since IoT implementation requires technical elements such as "sensing technology", "wired / wireless communication and network infrastructure", "service interface technology", and "security technology", sensor networks, machine - to - machine (M2M) communication, machine - type communication (MTC), etc. have been studied recently. Such an IoT environment can provide intelligent Internet technology services, creating new value for human life by collecting and analyzing data generated among interconnected things. IoT can be applied to various fields through the integration and combined application between existing information technology (IT) and various industrial applications, including smart homes, smart buildings, smart cities, smart cars or connected vehicles, smart grids, healthcare, smart appliances, and advanced medical services.

[0005] In line with this, various attempts have been made to apply 5G communication systems to IoT networks. For example, sensor networks, machine - type communication (MTC), and machine - to - machine (M2M) communication can be implemented through beamforming, MIMO, and array antennas. The application of cloud radio access network (RAN) as the big - data processing technology described above can also be regarded as an example of the integration between 5G technology and IoT technology.

[0006] Wireless communication has become one of the most successful innovations in modern history. Due to the increasing popularity of smartphones and other mobile data devices such as tablets, "notepad" computers, netbooks, e - book readers, and machine - type devices among consumers and businesses, the demand for wireless data services has grown rapidly. To meet the high growth of mobile data services and support new applications and deployments, improving radio interface efficiency and coverage is crucial. Summary of the Invention

[0007] Technical Problem

[0008] A mobile device or user equipment can measure the quality of the downlink channel and report this quality to the base station, enabling a decision to be made on whether various parameters should be adjusted during communication with the mobile device. The existing channel quality reporting process in wireless communication systems does not adequately accommodate the reporting of channel state information associated with large two - dimensional array transmit antennas or antenna array geometries that typically house a large number of antenna elements.

[0009] Solution to the Problem

[0010] In one embodiment, a UE is provided. The UE includes a transceiver and a processor operably connected to the transceiver. The transceiver is configured to receive (i) configuration information for CSI-RS and sounding reference signal (SRS), and (ii) a DCI including a downlink control information DCI field for an aperiodic SRS transmission request. The processor is configured to decode the configuration information and the DCI containing the aperiodic SRS transmission request. The transceiver is further configured to receive the CSI-RS and transmit the SRS. The SRS corresponds to a higher layer configured SRS resource, and the number of configured SRS resources is more than one.

[0011] In another embodiment, a base station (BS) is provided. The BS includes a processor and a transceiver operably connected to the processor. The processor is configured to generate (i) configuration information for CSI-RS and SRS, and (ii) a DCI including a DCI field for requesting an aperiodic SRS transmission. The transceiver is configured to transmit the configuration information, the DCI, and the CSI-RS to the UE via a DL channel; and receive the requested aperiodic SRS from the UE. The SRS corresponds to a higher layer configured SRS resource, and the number of configured SRS resources is more than one.

[0012] In yet another embodiment, a method for operating a UE is provided. The method includes: receiving and decoding (i) configuration information for channel state information reference signal (CSI-RS) and sounding reference signal (SRS), and (ii) downlink control information (DCI) including a DCI field for requesting an aperiodic SRS transmission. The method further includes: receiving the CSI-RS and transmitting the SRS. The SRS corresponds to a higher layer configured SRS resource, and the number of configured SRS resources is more than one.

[0013] In yet another embodiment, there is provided a user equipment (UE) operating in a wireless communication system. The UE includes: a transceiver and a processor. The processor is operably connected to the transceiver and is configured to: receive, from a base station, configuration information about a non-zero power channel state information reference signal (CSI-RS) resource associated with an aperiodic sounding reference signal (SRS), receive, from the base station, downlink control information including aperiodic SRS trigger information, receive, from the base station, a non-zero power CSI-RS associated with the non-zero power CSI-RS resource, wherein the non-zero power CSI-RS resource is identified based on the aperiodic SRS trigger information, identify an uplink precoder for the aperiodic SRS based on the received non-zero power CSI-RS, and transmit the aperiodic SRS to the base station, wherein when the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS trigger information and the non-zero power CSI-RS are received in the same time slot.

[0014] In yet another embodiment, there is provided a base station operating in a wireless communication system. The base station includes: a transceiver and a processor. The processor is operably connected to the transceiver and is configured to: transmit, to a user equipment (UE), configuration information about a non-zero power channel state information reference signal (CSI-RS) resource associated with an aperiodic sounding reference signal (SRS), transmit, to the UE, downlink control information including aperiodic SRS trigger information, transmit, to the UE, a non-zero power CSI-RS associated with the non-zero power CSI-RS resource, wherein the non-zero power CSI-RS resource is associated with the aperiodic SRS trigger information, and receive, from the UE, an aperiodic SRS based on an uplink precoder, wherein when the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS trigger information and the non-zero power CSI-RS are in the same time slot.

[0015] In yet another embodiment, there is provided a method performed by a user equipment (UE) operating in a wireless communication system. The method includes: receiving, from a base station, configuration information about a non-zero power channel state information reference signal (CSI-RS) resource associated with an aperiodic sounding reference signal (SRS), receiving, from the base station, downlink control information including aperiodic SRS trigger information, receiving, from the base station, a non-zero power CSI-RS associated with the non-zero power CSI-RS resource, wherein the non-zero power CSI-RS resource is identified based on the aperiodic SRS trigger information, identifying an uplink precoder for the aperiodic SRS based on the received non-zero power CSI-RS, and transmitting the aperiodic SRS to the base station, wherein when the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS trigger information and the non-zero power CSI-RS are received in the same time slot.

[0016] In yet another embodiment, a method performed by a base station operating in a wireless communication system is provided. The method includes: transmitting, to a user equipment (UE), configuration information on a non-zero power channel state information reference signal (CSI-RS) resource associated with an aperiodic sounding reference signal (SRS); transmitting, to the UE, downlink control information including aperiodic SRS triggering information; transmitting, to the UE, a non-zero power CSI-RS associated with the non-zero power CSI-RS resource, wherein the non-zero power CSI-RS resource is associated with the aperiodic SRS triggering information; and receiving, from the UE, an aperiodic SRS based on an uplink precoder, wherein, in a case where the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS triggering information and the non-zero power CSI-RS are in the same time slot.

[0017] The present disclosure relates to a quasi-fifth generation (5G) or 5G communication system to be provided for supporting higher data rates than fourth generation (4G) communication systems such as Long Term Evolution (LTE).

[0018] Those skilled in the art can readily understand other technical features from the following drawings, description, and claims.

[0019] Before presenting the following detailed description, it would be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The term "couple" and its derivatives refer to any direct or indirect communication between two or more elements, whether or not those elements are in physical contact with each other. The terms "transmit," "receive," and "communicate," and their derivatives, cover both direct and indirect communication. The terms "include" and "including," and their derivatives, mean including but not limited to. The term "or" is inclusive, meaning and / or. The phrase "associated with," and its derivatives, means including, included within, interconnected with, contains, contained within, connected to or connected with, coupled to or coupled with, capable of communicating with, cooperating with, interlacing, juxtaposed, proximate to, bound to or bound with, having, having the properties of, related to or having a relationship with, and the like. The term "controller" represents any device, system, or part thereof that controls at least one operation. Such a controller may be implemented in hardware or in a combination of hardware and software and / or firmware. The functionality associated with any particular controller may be centralized or distributed, whether local or remote. The phrase "at least one of" when used in conjunction with a list of items means that different combinations of one or more of the listed items may be used and only one item in the list may be required. For example, "at least one of A, B, and C" includes any of the following combinations: A; B; C; A and B; A and C; B and C; and A, B, and C.

[0020] In addition, the various functions described below can be implemented or supported by one or more computer programs, each of which is formed of computer-readable program code and embodied in a computer-readable medium. The terms "application program" and "program" refer to one or more computer programs, software components, instruction sets, procedures, functions, objects, classes, examples, associated data, or portions thereof that are adapted to be implemented with suitable computer-readable program code. The phrase "computer-readable program code" includes any type of computer code, including source code, object code, and executable code. The phrase "computer-readable medium" includes any type of medium that can be accessed by a computer, such as read-only memory (ROM), random access memory (RAM), hard disk drive, optical disk (CD), digital video disk (DVD), or any other type of memory. A "non-transitory" computer-readable medium excludes wired, wireless, optical, or other communication links that convey transitory electrical signals or other signals. Non-transitory computer-readable media include media in which data can be stored permanently and media in which data can be stored and later rewritten, such as rewritable optical disks or erasable memory devices.

[0021] Definitions of other specific words and phrases are provided throughout this patent document. One of ordinary skill in the art should understand that, in many if not most instances, such definitions apply to the prior as well as future use of such defined words and phrases.

[0022] Advantages of the Invention

[0023] Various embodiments of the present disclosure provide methods and apparatuses for the simultaneous use of DL and UL RS. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] To more fully understand the present disclosure and its advantages, reference is now made to the following description taken in conjunction with the accompanying drawings, in which like reference numerals represent like parts:

[0025] Figure 1 Illustrates an exemplary wireless network in accordance with various embodiments of the present disclosure;

[0026] Figure 2A and Figure 2B Illustrates an exemplary wireless transmit and receive path in accordance with various embodiments of the present disclosure;

[0027] Figure 3A Illustrates an exemplary user equipment in accordance with various embodiments of the present disclosure;

[0028] Figure 3B Illustrates an exemplary BS in accordance with various embodiments of the present disclosure;

[0029] Figure 4Shows an exemplary beamforming architecture where one CSI-RS port is mapped to a large number of analog-controlled antenna elements;

[0030] Figure 5 Shows an exemplary embodiment of a joint activation / deactivation mechanism when a UE is configured with both semi-persistent (SP) CSI-RS and SP-SRS according to an embodiment of the present disclosure;

[0031] Figure 6 Shows an exemplary embodiment of a joint activation / deactivation mechanism when a UE is configured with both aperiodic (AP) CSI-RS and AP-SRS according to an embodiment of the present disclosure;

[0032] Figure 7 Shows an exemplary embodiment of a DCI-based joint activation / deactivation mechanism when a UE is configured with both AP-CSI-RS and AP-SRS according to an embodiment of the present disclosure;

[0033] Figure 8 Shows an exemplary embodiment of AP-SRS triggering according to an embodiment of the present disclosure;

[0034] Figure 9 Shows an exemplary embodiment of AP-SRS triggering according to an embodiment of the present disclosure;

[0035] Figure 10 Shows a flowchart of an exemplary method according to an embodiment of the present disclosure, where a UE receives configuration information of CSI-RS and SRS; and

[0036] Figure 11 Shows a flowchart of an exemplary method according to an embodiment of the present disclosure, where a BS generates configuration information of CSI-RS and SRS for a UE (labeled as UE-k). Detailed Description

[0037] The following discussion Figures 1 to 11 And various embodiments described in this patent document for illustrating the principles of the present disclosure are merely for illustration purposes and should not be construed in any way as limiting the scope of the present disclosure. Those skilled in the art will understand that the principles of the present disclosure can be implemented by any suitably arranged wireless communication system.

[0038] List of Abbreviations

[0039] 2D: Two-dimensional

[0040] MIMO: Multiple-Input Multiple-Output

[0041] SU-MIMO: Single-User MIMO

[0042] MU-MIMO: Multi-User MIMO

[0043] 3GPP: The 3rd Generation Partnership Project

[0044] LTE: Long Term Evolution

[0045] UE: User Equipment

[0046] eNB: evolved Node B or "eNB"

[0047] BS: Base Station

[0048] DL: Downlink

[0049] UL: Uplink

[0050] CRS: Cell-specific Reference Signal

[0051] DMRS: Demodulation Reference Signal

[0052] SRS: Sounding Reference Signal UE-RS: UE-specific Reference Signal CSI-RS: Channel State Information Reference Signal SCID: Scrambling Identity

[0053] MCS: Modulation and Coding Scheme

[0054] RE: Resource Element

[0055] CQI: Channel Quality Information

[0056] PMI: Precoding Matrix Indicator

[0057] RI: Rank Indicator

[0058] MU-CQI: Multi-User CQI

[0059] CSI: Channel State Information CSI-IM: CSI Interference Measurement

[0060] CoMP: Coordinated Multi-Point

[0061] DCI: Downlink Control Information

[0062] UCI: Uplink Control Information PDSCH: Physical Downlink Shared Channel PDCCH: Physical Downlink Control Channel PUSCH: Physical Uplink Shared Channel PUCCH: Physical Uplink Control Channel PRB: Physical Resource Block

[0063] RRC: Radio Resource Control

[0064] AoA: Angle of Arrival

[0065] AoD: Angle of Departure

[0066] The following documents and standards are incorporated herein by reference as if fully set forth herein: 3GPP Technical Specification (TS) 36.211 version 12.4.0, "E-UTRA, Physical Channels and Modulation" ("REF 1"); 3GPP TS 36.212 version 12.3.0, "E-UTRA, Multiplexing and Channel Coding" ("REF 2"); 3GPP TS 36.213 version 12.4.0, "E-UTRA, Physical Layer Procedures" ("REF 3"); 3GPP TS 36.321 version 12.4.0, "E-UTRA, Medium Access Control (MAC) Protocol Specification" ("REF 4"); 3GPP TS 36.331 version 12.4.0, "E-UTRA, Radio Resource Control (RRC) Protocol Specification" ("REF 5"); 3GPP Technical Specification (TS) 38.211 version 15.0.0, "NR, Physical Channels and Modulation" ("REF 6"); 3GPP TS 38.212 version 15.0.0, "NR, Multiplexing and Channel Coding" ("REF 7"); 3GPP TS 38.213 version 15.0.0, "NR, Physical Layer Procedures for Control" ("REF 8"); 3GPP TS 38.214 version 15.0.0, "NR, Physical Layer Procedures for Data" ("REF 9"); 3GPP TS 38.321 version 15.0.0, "NR, Medium Access Control (MAC) Protocol Specification" ("REF 10"); and 3GPP TS 38.331 version 15.0.0, "NR, Radio Resource Control (RRC) Protocol Specification" ("REF 11").

[0067] To meet the demand for wireless data services that has increased since the deployment of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems".

[0068] The 5G communication system is considered to be implemented in a higher frequency (millimeter wave) band, such as the 60 GHz band, in order to achieve higher data rates. In order to reduce the propagation loss of radio waves and increase the transmission distance, beamforming, massive multiple-input multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and massive antenna technologies are discussed in the 5G communication system.

[0069] In addition, in the 5G communication system, the development of system network improvements is ongoing based on advanced small cells, cloud radio access network (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, coordinated multi-point (CoMP), receiver interference cancellation, and so on.

[0070] In a 5G system, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) as advanced coding modulation (ACM), as well as filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA), and sparse code multiple access (SCMA) as advanced access technologies have been developed.

[0071] Figure 1 An exemplary wireless network 100 according to various embodiments of the present disclosure is shown. Figure 1 The embodiments of the wireless network 100 shown are for illustrative purposes only. Other embodiments of the wireless network 100 may be used without departing from the scope of the present invention.

[0072] The wireless network 100 includes base stations (BSs) 101, 102, and 103. BS 101 communicates with BS 102 and BS 103. BS 101 also communicates with at least one Internet Protocol (IP) network 130, such as the Internet, a proprietary IP network, or other data networks. Instead of "BS", alternative terms such as "eNB" (enhanced Node B) or "gNB" (general Node B) may also be used. Depending on the network type, other well-known terms may be used instead of "gNB" or "BS", such as "base station" or "access point". For convenience, the terms "gNB" and "BS" are used in this patent document to refer to the network infrastructure components that provide wireless access to remote terminals. Additionally, depending on the network type, other well-known terms may be used instead of "user equipment" or "UE", such as "mobile station", "subscriber station", "remote terminal", "wireless terminal", or "user device". For convenience, the terms "user equipment" and "UE" are used in this patent document to refer to the remote wireless devices that wirelessly access the gNB, regardless of whether the UE is a mobile device (such as a mobile phone or smartphone) or is generally considered a fixed device (such as a desktop computer or vending machine).

[0073] gNB 102 provides wireless broadband access to network 130 for a first plurality of user equipments (UEs) located within coverage area 120 of gNB 102. The first plurality of UEs includes UE 111, which may be located in a small business (SB); UE 112, which may be located in an enterprise (E); UE 113, which may be located in a WiFi hotspot (HS); UE 114, which may be located in a first residence (R); UE 115, which may be located in a second residence (R); and UE 116, which may be a mobile device (M), such as a mobile phone, a wireless laptop computer, a wireless PDA, etc. gNB 103 provides wireless broadband access to network 130 for a second plurality of UEs located within coverage area 125 of gNB 103. The second plurality of UEs includes UE 115 and UE 116. In some embodiments, one or more of gNBs 101 to 103 may communicate with each other and with UEs 111 to 116 using 5G, LTE, LTE-A, WiMAX, or other advanced wireless communication technologies.

[0074] The dashed lines illustrate the approximate extents of coverage areas 120 and 125, which are shown as approximately circular only for purposes of illustration and explanation. It should be clearly understood that the coverage areas associated with gNBs (such as coverage areas 120 and 125) may have other shapes, including irregular shapes, depending on the configuration of the gNBs and variations in the radio environment associated with natural and man-made obstacles.

[0075] As described in more detail below, one or more of gNBs 101, 102, and 103 transmit measurement reference signals to UEs 111 to 116 and configure UEs 111 to 116 for CSI reporting, as described in embodiments of the present invention. In various embodiments, one or more of UEs 111 to 116 receive channel state information reference signals (CSI-RS) and transmit sounding reference signals (SRS).

[0076] Although Figure 1 illustrates one example of wireless network 100, various changes may be made to Figure 1 it. For example, wireless network 100 may include any number of gNBs and any number of UEs in any suitable arrangement. Additionally, gNB 101 may communicate directly with any number of UEs and provide wireless broadband access to network 130 to those UEs. Similarly, each of gNBs 102 to 103 may communicate directly with network 130 and provide direct wireless broadband access to network 130 to UEs. Further, gNBs 101, 102, and / or 103 may provide access to other or additional external networks (such as an external telephone network or other types of data networks).

[0077] Figure 2A and Figure 2B illustrates an exemplary wireless transmit and receive path in accordance with the present disclosure. In the following description, the transmit path 200 may be described as implemented in a gNB (such as gNB 102), while the receive path 250 may be described as implemented in a UE (such as UE 116). However, it will be understood that the receive path 250 may be implemented in the gNB and the transmit path 200 may be implemented in the UE. In some embodiments, the receive path 250 is configured to receive CSI-RS and transmit SRS, as described in embodiments of the present disclosure.

[0078] The transmit path 200 includes a channel coding and modulation block 205, a serial-to-parallel (S-to-P) block 210, an N-point inverse fast Fourier transform (IFFT) block 215, a parallel-to-serial (P-to-S) block 220, a "cyclic prefix addition block" 225, and an upconverter (UC) 230. The receive path 250 includes a downconverter (DC) 255, a "cyclic prefix removal block" 260, a serial-to-parallel (S-to-P) block 265, an N-point fast Fourier transform (FFT) block 270, a parallel-to-serial (P-to-S) block 275, and a channel decoding and demodulation block 280.

[0079] In the transmit path 200, the channel coding and modulation block 205 receives a set of information bits, applies coding (such as convolutional, turbo, or low-density parity-check (LDPC) coding), and modulates the input bits (such as with quadrature phase shift keying (QPSK) or quadrature amplitude modulation (QAM)) to produce a sequence of frequency-domain modulated symbols. The serial-to-parallel block 210 converts (such as demultiplexes) the serially modulated symbols into parallel data to produce N parallel symbol streams, where N is the IFFT / FFT size used in gNB 102 and UE 116. The N-point IFFT block 215 performs an IFFT operation on the N parallel symbol streams to produce a time-domain output signal. The parallel-to-serial block 220 converts (such as multiplexes) the parallel time-domain output symbols from the N-point IFFT block 215 to produce a serial time-domain signal. The "cyclic prefix addition" block 225 inserts a cyclic prefix into the time-domain signal. The UC 230 modulates (such as upconverts) the output of the "cyclic prefix addition" block 225 to an RF frequency for transmission over the wireless channel. The signal may also be filtered in the baseband before being converted to the RF frequency.

[0080] The RF signal transmitted from gNB 102 reaches UE 116 after passing through the wireless channel, and operations opposite to those at gNB 102 are performed at UE 116. DC 255 down-converts the received signal to baseband frequency, and the "remove cyclic prefix" block 260 removes the cyclic prefix to produce a serial time-domain baseband signal. The serial-to-parallel block 265 converts the time-domain baseband signal to a parallel time-domain signal. The size NFFT block 270 performs the FFT algorithm to produce N parallel frequency-domain signals. The parallel-to-serial block 275 converts the parallel frequency-domain signals to a sequence of modulated data symbols. The channel decoding and demodulation block 280 demodulates and decodes the modulated symbols to recover the original input data stream.

[0081] As described in more detail below, the transmit path 200 or the receive path 250 may perform signaling for CSI reporting. Each of gNBs 101 to 103 may implement the transmit path 200, which is similar to transmitting to UEs 111 to 116 in the downlink, and may implement the receive path 250, which is similar to receiving from UEs 111 to 116 in the uplink. Similarly, each of UEs 111 to 116 may implement the transmit path 200 for transmitting to gNBs 101 to 103 in the uplink, and may implement the receive path 250 for receiving from gNBs 101 to 103 in the downlink.

[0082] Each of the components in Figure 2A and Figure 2B can be implemented using only hardware or a combination of hardware and software / firmware. As a specific example, Figure 2A and Figure 2B at least some of the components in can be implemented in software, while other components can be implemented by configurable hardware or a mixture of software and configurable hardware. For example, the FFT block 270 and the IFFT block 215 can be implemented as configurable software algorithms, where the value of the size N can be modified according to the implementation scenario.

[0083] Furthermore, although described as using FFT and IFFT, this is for illustration only and should not be construed as limiting the scope of the present invention. Other types of transforms, such as the discrete Fourier transform (DFT) and the inverse discrete Fourier transform (IDFT) functions, can be used. It will be understood that the value of the variable N can be any integer number for the DFT and IDFT functions (such as 1, 2, 3, 4, etc.), while the value of the variable N for the FFT and IFFT functions can be any integer number that is a power of two (such as 1, 2, 4, 8, 16, etc.).

[0084] Although Figure 2A and Figure 2B show examples of wireless transmit and receive paths, Figure 2A and Figure 2BMake various changes. For example, Figure 2A and Figure 2B the various components in can be combined, further subdivided, or omitted, and additional components can be added according to specific needs. Additionally, Figure 2A and Figure 2B are intended to show examples of types of transmit and receive paths that can be used in a wireless network. Other suitable architectures can be used to support wireless communication in a wireless network.

[0085] Figure 3A Show an exemplary UE 116 according to the present disclosure. Figure 3A The embodiments of the UE 116 shown in are for illustration purposes only, and Figure 1 UEs 111 to 115 may have the same or similar configurations. However, UEs have a wide variety of configurations, and Figure 3A does not limit the scope of the present disclosure to any particular implementation of the UE.

[0086] UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, a transmit (TX) processing circuit 315, a microphone 320, and a receive (RX) processing circuit 325. UE 116 also includes a speaker 330, a processor 340, an input / output (I / O) interface (IF) 345, an input terminal 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) program 361 and one or more application programs 362.

[0087] The RF transceiver 310 receives incoming RF signals transmitted by the gNB of the Figure 1 wireless network 100 from the antenna 305. The RF transceiver 310 down-converts the incoming RF signals to produce an intermediate frequency (IF) or baseband signal. The IF or baseband signal is sent to the RX processing circuit 325, which produces a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuit 325 transmits the processed baseband signal to the speaker 330 (such as for voice data) or the processor 340 for further processing (such as for web browsing data).

[0088] The TX processing circuit 315 receives analog or digital voice data from the microphone 320 or other outgoing baseband data from the processor 340 (such as network data, email, or interactive video game data). The TX processing circuit 315 encodes, multiplexes, and / or digitizes the outgoing baseband data to produce a processed baseband or IF signal. The RF transceiver 310 receives the outgoing processed baseband or IF signal from the TX processing circuit 315 and up-converts the baseband or IF signal to an RF signal transmitted through the antenna 305.

[0089] The processor 340 may include one or more processors or other processing devices that execute the OS program 361 stored in the memory 360 to control the overall operation of the UE 116. For example, the processor 340 may control the reception of forward channel signals and the transmission of reverse channel signals via the RF transceiver 310, the RX processing circuit 325, and the TX processing circuit 315 according to well-known principles. In some embodiments, the processor 340 includes at least one microprocessor or microcontroller.

[0090] The processor 340 is also capable of executing other processes and programs resident in the memory 360, such as operations for CSI-RS reception and measurement in the systems described in the embodiments of the present disclosure, as described in the embodiments of the present disclosure. The processor 340 may execute processes as needed to move data into or out of the memory 360. In some embodiments, the processor 340 is configured to execute the application program 362 based on the OS program 361 or in response to signals received from the gNB or the operator. The processor 340 is also coupled to the I / O interface 345, which provides the UE 116 with the ability to connect to other devices (such as laptop computers and handheld computers). The I / O interface 345 is the communication path between these accessories and the processor 340.

[0091] The processor 340 is also coupled to the input terminal 350 (such as a keypad, touch screen, buttons, etc.) and the display 355. The operator of the UE 116 may use the input terminal 350 to input data into the UE 116. The display 355 may be a liquid crystal display or other display that is capable of rendering text and / or at least a limited amount of graphics, such as from a website.

[0092] The memory 360 is coupled to the processor 340. A portion of the memory 360 may include random access memory (RAM), and another portion of the memory 360 may include flash memory or other read-only memory (ROM).

[0093] As described in more detail below, the UE 116 may perform signaling and calculations for CSI reporting. Although Figure 3A shows an example of the UE 116, various changes may be made to Figure 3A For example, Figure 3A the various components in Figure 3A may be combined, further subdivided, or omitted, and additional components may be added according to specific needs. As a specific example, the processor 340 may be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Additionally, although shows the UE 116 configured as a mobile phone or smartphone, the UE may be configured to operate as other types of mobile or fixed devices.

[0094] Figure 3B Illustrates an exemplary gNB 102 according to the present disclosure. Figure 3B The embodiment of the gNB 102 shown in is for illustration only, and Figure 1 other gNBs may have the same or similar configurations. However, gNBs have a wide variety of configurations, and Figure 3B does not limit the scope of the present disclosure to any particular implementation of the gNB. gNB 101 and gNB 103 may include structures that are the same as or similar to those of gNB 102.

[0095] As Figure 3B shown, the gNB 102 includes a plurality of antennas 370a to 370n, a plurality of RF transceivers 372a to 372n, a transmit (TX) processing circuit 374, and a receive (RX) processing circuit 376. In some implementations, one or more of the plurality of antennas 370a to 370n include a 2D antenna array. The gNB 102 also includes a controller / processor 378, a memory 380, and a backhaul or network interface 382.

[0096] The RF transceivers 372a to 372n receive incoming RF signals from the antennas 370a to 370n, such as signals transmitted by a UE or other gNBs. The RF transceivers 372a to 372n down-convert the incoming RF signals to generate IF or baseband signals. The IF or baseband signals are sent to the RX processing circuit 376, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. The RX processing circuit 376 transmits the processed baseband signal to the controller / processor 378 for further processing.

[0097] The Tx processing circuit 374 receives analog or digital data (such as voice data, network data, email, or interactive video game data) from the controller / processor 378. The TX processing circuit 374 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceivers 372a to 372n receive the outgoing processed baseband or IF signal from the TX processing circuit 374 and up-convert the baseband or IF signal to an RF signal transmitted through the antennas 370a to 370n.

[0098] The controller / processor 378 may include one or more processors or other processing devices that control all operations of the gNB 102. For example, the controller / processor 378 may control the RF transceivers 372a to 372n, the RX processing circuitry 376, and the TX processing circuitry 374 to receive forward channel signals and transmit reverse channel signals according to well-known principles. The controller / processor 378 may also support additional functions, such as more advanced wireless communication functions. In some embodiments, the controller / processor 378 includes at least one microprocessor or microcontroller.

[0099] The controller / processor 378 is also capable of executing programs and other processes residing in the memory 380, such as the OS. The controller / processor 378 is also capable of supporting channel quality measurement and reporting for a system with a 2D antenna array, as described in embodiments of the present invention. In some embodiments, the controller / processor 378 supports communication between entities (such as network RTCs). The controller / processor 378 may move data into or out of the memory 380 according to the requirements of the executing processes.

[0100] The controller / processor 378 is also coupled to a backhaul or network interface 382. The backhaul or network interface 382 allows the gNB 102 to communicate with other devices or systems via a backhaul connection or via a network. The backhaul or network interface 382 may support communication over any suitable wired or wireless connection. For example, when the gNB 102 is implemented as part of a cellular communication system (such as a system supporting 5G or new radio access technology or NR, LTE, or LTE-A), the backhaul or network interface 382 may allow the gNB 102 to communicate with other gNBs via a wired or wireless backhaul connection. When the gNB 102 is implemented as an access point, the backhaul or network interface 382 may allow the gNB 102 to communicate via a wired or wireless local area network or via a wired or wireless connection to a larger network (such as the Internet). The backhaul or network interface 382 includes any suitable structure that supports communication over a wired or wireless connection, such as Ethernet or an RF transceiver.

[0101] The memory 380 is coupled to the controller / processor 378. A portion of the memory 380 may include RAM, and another portion of the memory 380 may include flash memory or other ROM. In certain implementations, multiple instructions, such as the BIS algorithm, are stored in the memory. The multiple instructions are configured to cause the controller / processor 378 to execute a BIS process and decode the received signals after subtracting at least one interference signal determined by the BIS algorithm.

[0102] As described in more detail below, the transmit and receive paths of geNB 102 (implemented using RF transceivers 372a through 372n, TX processing circuitry 374, and / or RX processing circuitry 376) allocate and transmit CSI-RS and allocate and receive SRS.

[0103] Although Figure 3B an example of gNB 102 is shown, various changes may be made to Figure 3B it. For example, gNB 102 may include Figure 3A any number of each component shown in. As a specific example, an access point may include multiple backhaul or network interfaces 382, and the controller / processor 378 may support routing functions to forward data between different network addresses. As another specific example, although shown as including a single instance of TX processing circuitry 374 and a single instance of RX processing circuitry 376, gNB 102 is capable of including multiple instances of each (such as one instance per RF transceiver).

[0104] Rel.13 LTE supports up to 16 CSI-RS antenna ports, which enables gNBs to be equipped with a large number of antenna elements (such as 64 or 128). In this case, multiple antenna elements are mapped to one CSI-RS port. Additionally, Rel.14 LTE will support up to 32 CSI-RS ports. For next-generation cellular systems, such as 5G, it is expected that the maximum number of CSI-RS ports will remain more or less the same.

[0105] For the millimeter wave band, although the number of antenna elements may be large for a given form factor, due to hardware limitations (such as the feasibility of mounting a large number of ADC / DACs at millimeter wave frequencies), the number of CSI-RS ports corresponding to the number of digitally precoded ports tends to be limited, as shown in Figure 4 Example 400 of. In this case, one CSI-RS port is mapped to a large number of antenna elements that can be controlled by a set of analog phase shifters 401. One CSI-RS port can then correspond to a subarray that generates a narrow analog beam through analog beamforming 405. This analog beam can be configured to sweep a wide angular range 420 by changing the set of phase shifters across symbols or subframes or time slots (where a subframe or time slot includes a set of symbols). The number of subarrays (equal to the number of RF chains) is the same as the number of CSI-RS ports N CSI-PORT . The digital beamforming unit 410 performs a linear combination of the N CSI-PORT analog beams to further increase the precoding gain. Although the analog beams are broadband (and thus not frequency selective), the digital precoding can be changed across frequency subbands or resource blocks.

[0106] The UE is configured with CSI-RS for DL CSI measurement and reporting. The allocation unit for CSI-RS can be referred to as a CSI-RS resource, which can correspond to non-zero power (NZP) or zero power (ZP). NZP CSI-RS is mainly used for channel measurement, while ZP CSI-RS is used for interference measurement. For 5G NR, the NZP CSI-RS resource is defined as a set of NZP CSI-RS ports mapped to a set of REs within a frequency span / duration, which can be measured at least to derive CSI. Multiple NZP CSI-RS resources can be configured for the UE to support CoMP, beam management, and operations based on multiple beamformed CSI-RS, where each NZP CSI-RS resource can have a different number of CSI-RS ports. When measuring the allocated CSI-RS, the UE calculates DL CSI and reports it to the gNB / network. The gNB / network utilizes the reported DL CSI for DL link adaptation and scheduling.

[0107] Similarly, the UE is configured with SRS for UL CSI measurement. The allocation unit for SRS can be referred to as an SRS resource, which can also correspond to non-zero power (NZP) or zero power (ZP) like CSI-RS. NZP SRS is mainly used for channel measurement, while ZP SRS is used for interference measurement. For 5G NR, the SRS resource is defined as a set of SRS ports mapped to a set of REs within a frequency span / duration, which can be measured at least to derive CSI. Multiple SRS resources can be configured for the UE to support beam management and operations based on multiple beamformed SRS, where each SRS resource can have a different number of SRS ports. When measuring the SRS transmitted by the UE, the gNB / network calculates UL CSI and uses it for DL link adaptation and scheduling.

[0108] In some deployment scenarios such as TDD, half-duplex, or FDD with a small DL-UL duplex distance, DL-UL channel reciprocity (partial or complete) is feasible. In particular, when complete DL-UL channel reciprocity is available, it can be used to improve CSI acquisition - for both DL and UL. Here, the simultaneous use of CSI-RS and SRS is beneficial. In addition, joint CSI-RS / SRS operations (including configuration as well as CSI measurement, calculation, and / or reporting processes) contribute to more efficient utilization and improved CSI accuracy.

[0109] Therefore, there is an additional need to design processes that can improve the joint utilization between CSI-RS and SRS for DL / UL CSI acquisition.

[0110] Table 1 outlines four scenarios where the UE is configured with CSI-RS and SRS. Scenarios I and II are typical scenarios for DL and UL CSI acquisition respectively. For Scenario I, only CSI-RS is used, while for Scenario II, only SRS is used. When DL-UL channel reciprocity is available and the UE is configured with SRS, Scenario III can be used, such that the gNB can measure the SRS to improve UL CSI. Here, the standalone SRS is usually insufficient because even when DL-UL channel reciprocity holds, the DL and UL interference distributions are usually not reciprocal. Therefore, CSI-RS and SRS need to be jointly utilized. For example, the CSI report from the UE can be used together with the SRS and the measured channel. When DL-UL channel reciprocity is available and the UE is configured with CSI-RS, Scenario IV can be used, such that the UE can measure the CSI-RS to improve UL CSI acquisition. Similarly, the standalone CSI-RS is usually insufficient because even when DL-UL channel reciprocity holds, the DL and UL interference distributions are usually not reciprocal. Therefore, CSI-RS and SRS need to be jointly utilized. For example, the precoding information from the associated UL-related DCI (transmitting PMI and RI) can be used together with the CSI-RS and the measured channel to improve UL precoding.

[0111]

Table 1

[0112]

[0113] For Scenarios III and IV, although implementation-based schemes can be used, some limitations and procedures for jointly configuring CSI-RS and SRS may be beneficial.

[0114] This disclosure includes the following components. The first component of the present invention pertains to SRS-assisted DL CSI acquisition (see Scenario III). The second component pertains to CSI-RS-assisted UL CSI acquisition (see Scenario IV). Each of these components can be used alone (without using other components) or in combination with at least one of the other components. Similarly, each of these components includes multiple sub-components. Each of the sub-components can be used alone (without using any other sub-components) or in combination with at least one of the other sub-components.

[0115] Consider three time-domain behaviors of CSI-RS as well as SRS: periodic (P), semi-persistent (SP), and aperiodic (AP).

[0116] To describe embodiments, the NR CSI framework is used throughout this disclosure. A UE may be configured with N≥1 CSI report settings, M≥1 resource settings, and measurement settings, where the measurement settings include L≥1 links. Each link associates a CSI report setting and a resource setting and configures other functions, such as measurement quantities (channels or interference). Channel / interference measurement limitations may be included in the link, CSI report setting, or resource setting. A CSI report setting may be linked to one or more resource settings. Similarly, a resource setting may be linked to one or more CSI report settings.

[0117] All or at least one of the following components and embodiments apply to transmissions having a CP-OFDM (Cyclic Prefix OFDM) waveform as well as DFT-SOFDM (DFT-spread OFDM) and SC-FDMA (Single Carrier FDMA) waveforms. Additionally, all or at least one of the following components and embodiments apply to transmissions when the scheduling unit is a subframe (which may include one or more time slots) or a time slot in time.

[0118] For a first component (i.e., SRS-assisted DL CSI acquisition), CSI-RS may be used for DL channel and DL interference measurements at the UE, where the UE measures the channel and interference via CSI-RS (NZP or ZP, or both), calculates the CSI, and reports the CSI to the gNB / network. The same holds for beam management (BM), where the UE calculates and reports beam reports (such as RSRP and other beam-related information). Thus, the gNB obtains DL CSI through CSI / BM reports. When DL-UL channel reciprocity is feasible, SRS may be used to enhance DL channel measurements (such as providing higher channel measurement resolution). Here, the UE is configured to transmit SRS measured by the gNB / network. Due to channel reciprocity, the UL channel measured via SRS can provide a good approximation of the associated DL channel. Thus, the UE may be configured with CSI-RS and SRS for the purpose of DL channel acquisition.

[0119] The following embodiments include processes that may be used to configure a UE with CSI-RS and SRS for the purpose of DL channel acquisition. Each embodiment includes at least a link between CSI-RS and SRS, which the UE may assume for DL channel / interference measurements, CSI-RS / SRS timing relationships, and DL CSI calculations.

[0120] In one embodiment (I.A), the CSI report setting is linked to at least two resource settings: one for CSI-RS and one for SRS. For these two resource settings, the number of SRS ports can be set to be equal to the number of UE RX ports. In the case where multiple resource settings are linked to one CSI report setting, at least some of the following sub - embodiments can be used.

[0121] In the first sub - embodiment (Scenario 1), the first resource setting is configured for NZP CSI-RS and for DL channel and DL interference measurements. The second resource setting is configured for (NZP) SRS and for DL channel measurements (gNB / network measurements via the UL channel). In the second sub - embodiment (Scenario 2), the first resource setting is configured for NZP CSI-RS and for DL interference measurements. The second resource setting is configured for (NZP) SRS and for DL channel measurements (gNB / network measurements via the UL channel). In the third sub - embodiment (Scenario 3), the first resource setting is configured for ZP CSI-RS and for DL interference measurements. The second resource setting is configured for (NZP) SRS and for DL channel measurements (gNB / network measurements via the UL channel). In the fourth sub - embodiment (Scenario 4), at least three resource settings can be used. The first resource setting is configured for NZP CSI-RS and for DL channel measurements. The second resource setting is configured for (NZP) SRS and for DL channel measurements (gNB / network measurements via the UL channel). The third resource setting is configured for ZP CSI-RS or NZP CSI-RS or DLDMRS, for DL interference measurements.

[0122] For Scenario 1 and Scenario 4, two resource settings (and thus two types of resources: CSI-RS and SRS) are used for DL channel measurements. This can mean that the UE can measure based on this the first resource setting (using NZP CSI-RS) and calculate the CSI report (using another resource for DL interference measurements for Scenario 4). At the same time, the UE transmits SRS in DL CSI acquisition to assist the gNB / network (where the gNB / network can use the CSI report in combination with its measurements of the SRS for link adaptation and scheduling).

[0123] For the above sub - embodiments of this embodiment, in a resource setting including SRS resource configuration (which may include one or more SRS resources), a parameter (referred to as "function" in this disclosure for illustrative purposes) indicating its use for DL CSI acquisition (as opposed to UL CSI acquisition) can be used. This parameter can take two values, such as "DL CSI" or "UL CSI". When the SRS is configured in this way (for DL CSI acquisition), the TX (transmission) precoding applied to the SRS (by the UE) should be the same as (or at least match) the RX (reception) precoding applied to the UE RX port (for the purpose of receiving DL transmissions). Here, a certain type of QCL / correspondence between this SRS (in one resource setting) and the configured CSI - RS (in another resource setting) can be used. This correspondence between the CSI - RS and the SRS can be part of or supplementary to the parameter "function", or can be configured separately. Note that if the configured CSI - RS includes K>1 resources, the number of SRS resources can also include K>1 resources, where each of the K CSI - RS resources corresponds to one of the K SRS resources. In this case, the correspondence includes K links. Optionally, the number of SRS resources K'≥1 is not necessarily equal to K. In this case, a correspondence between K'≥1 SRS resources and K>1 CSI - RS resources can also be configured. This configured correspondence can be used, for example, for aperiodic CSI - RS and aperiodic SRS. This correspondence can facilitate the joint triggering of CSI - RS and SRS (dynamically performed via the L1 DL control channel). In this case, the correspondence can be a mapping between the code point of the DCI field for joint triggering and the SRS resource index (each corresponding to a CSI - RS resource index). This correspondence information can be signaled via higher - layer (e.g., RRC) signaling or MAC Ce (control element).

[0124] Regarding SRS resource configuration, at least the following mechanisms related to time - domain behavior are relevant.

[0125] In the first mechanism, when the P / SP - CSI - RS and P / SP - SRS are configured in this way (four possible combinations: P - CSI - RS+P - SRS, P - CSI - RS+SP - SRS, SP - CSI - RS+P - SRS, and SP - CSI - RS+SP - SRS), the relationship between the sub - frame configuration or slot configuration of these CSI - RS and SRS can be utilized (which includes slot / sub - frame offset and periodicity). For example, the SRS periodicity can be set to an integer multiple of the CSI - RS periodicity, while the SRS slot / sub - frame offset can be defined relative to the CSI - RS slot / sub - frame offset.

[0126] When configuring SP-CSI-RS and SP-SRS, the SP-SRS can share the same activation / deactivation with the SP-CSI-RS. Sharing the same activation / deactivation means using one resource activation / deactivation message to activate or deactivate both the SP-CSI-RS and the SP-SRS. This message can be signaled to the UE via MAC Ce (control element) or L1 DL control signaling (using DL-related or UL-related DCI). When the UE receives an activation message in slot / subframe n, the UE can assume that starting from slot / subframe n+D1 (where D1 can be specified, configured via higher layer signaling, or signaled via L1 Dl control signaling), the UE can use the configuration information given in the CSI-RS resource setup (including resource index / index, periodicity, and slot / subframe offset) to measure the CSI-RS, and use the configuration information given in the SRS resource setup (including resource index / index, periodicity, and slot / subframe offset) to transmit the SRS. Similarly, when the UE receives a deactivation message in slot / subframe n, the UE can assume that starting from slot / subframe n+D2 (where D2 can be specified, configured via higher layer signaling, or signaled via L1 Dl control signaling), the UE can stop using the configuration information given in the CSI-RS resource setup (including resource index / index, periodicity, and slot / subframe offset) to measure the CSI-RS, and stop using the configuration information given in the SRS resource setup (including resource index / index, periodicity, and slot / subframe offset) to transmit the SRS. Since the CSI-RS and SRS resource configurations are usually different, the activation / deactivation message can include two resource configuration fields - one for the CSI-RS and the other for the SRS.

[0127] If K>1 resources are configured for the CSI-RS, the configuration field in the activation / deactivation message can also include an N-subset selection of the K resources (1≤N≤K). Similarly, if K'>1 resources are configured for the SRS, the configuration field in the activation / deactivation message can also include an N'-subset selection of the K' resources (1≤N'≤K'). The values of N and N' can be configured via higher layer signaling or inferred from the activation message (explicitly or implicitly) via MAC CE.

[0128] The embodiments in the previous paragraph can also be applied to S>1 CSI-RS resource sets instead of K>1 CSI-RS resources. Or it can also be applied to S'>1 SRS resource sets instead of K'>1 SRS resources.

[0129] When the UE is configured with another CSI-RS (NZP or ZP, such as Scenario 4) - via another resource setup - for DL interference measurement, this mechanism can be extended. In this case, the activate / release message also includes the configuration information related to the other CSI-RS.

[0130] Figure 5 FIG. 500 shows the joint activation / deactivation mechanism when the UE is configured with SP-CSI-RS having K>1 resources and SP-SRS having K'>1 resources. When the UE receives the activation message 501 indicating the activation of SP-CSI-RS resource subset 1 and SP-SRS resource subset 1, after a certain (specified or configured) delay, the UE assumes to calculate the SP-CSI based on the SP-CSI-RS associated with the SP-CSI-RS resource subset 1, and transmits the SP-SRS associated with the SP-SRS resource subset 1 in the same time slot / subframe as the SP-CSI report. Then, when the UE receives another activation message 502, these subsets are replaced by SP-CSI-RS subset 2 and SP-SRS subset 2. Subsequently, when the UE receives another activation message 503, these subsets are replaced by SP-CSI-RS subset 3 and SP-SRS subset 3.

[0131] In the second mechanism, when the AP-CSI-RS and AP-SRS are configured in such a way, the same DCI is used to trigger the A-CSI report and the AP-SRS transmission in the same time slot / subframe where there is an AP-CSI-RS. Thus, when the UE receives UL-related or DL-related DCI including the CSI request field and the CSI request field that is ON (indicating a request for an A-CSI report) in time slot / subframe n, the UE will report the A-CSI and transmit the AP-SRS in time slot / subframe n+D3 (where D3 can be specified, or configured via higher layer signaling, or signaled via L1 DL control signaling). Thus, the gNB / network receives the A-CSI report and the AP-SRS transmission in the same time slot / subframe.

[0132] When both AP-CSI-RS and AP-SRS are configured with multiple resources (K > 1 resources are configured for CSI-RS and K' > 1 resources are configured for SRS), AP-SRS can share the same activation with AP-CSI-RS. Sharing the same activation means using one resource activation message to perform N subset selections (1 ≤ N ≤ K) for the K resources of AP-CSI-RS and N' subset selections (1 ≤ N' ≤ K') for the K' resources of AP-SRS. This message can be signaled to the UE via MAC Ce (control element) or L1 DL control signaling (using DL-related or UL-related DCI). When the UE receives the activation message in slot / subframe n, the UE can assume that starting from slot / subframe n + D4 (where D1 can be specified, either configured via higher layer (e.g., RRC) signaling or signaled via L1 Dl signaling), it selects the N subset of AP-CSI-RS resources and the N' subset of AP-SRS resources indicated in the resource selection information (in the activation message). Since CSI-RS and SRS resource configurations are usually different, the activation / deactivation message can include two resource configuration fields - one for CSI-RS and the other for SRS.

[0133] The embodiments in the previous paragraph can also be applied to S > 1 CSI-RS resource sets instead of K > 1 CSI-RS resources. Or it can also be applied to S' > 1 SRS resource sets instead of K' > 1 SRS resources.

[0134] Figure 6 The illustration 600 shows the joint activation / deactivation mechanism when the UE is configured with AP-CSI-RS having K > 1 resources and AP-SRS having K' > 1 resources. When the UE receives the activation message 601 indicating the AP-CSI-RS resource subset 1 and the AP-SRS resource subset 1, after a certain (specified or configured) delay, the UE assumes the selection of the AP-CSI-RS resource subset 1 and the AP-SRS resource subset 1. Then, when the UE receives another activation message 602, these subsets are replaced by the AP-CSI-RS subset 2 and the AP-SRS subset 2. Subsequently, when the UE receives another activation message 603, these subsets are replaced by the AP-CSI-RS subset 3 and the AP-SRS subset 3.

[0135] The values of N and N’ can be configured via higher layer signaling or inferred (either explicitly or implicitly from the activation message) via a MAC CE. If N > 1 and / or N’ > 1, the UE is configured with N AP-CSI-RS resources and / or N’ AP-SRS resources. One of the N AP-CSI-RS resources and / or one of the N’ AP-SRS resources can be selected. The same DCI including a CSI request field or another mechanism (such as via a MAC CE, especially when the UE is configured with multiple component carriers) can be used to perform this selection.

[0136] Figure 7 Illustration 700 shows an exemplary use of the joint resource activation and A-CSI reporting mechanism when the UE is configured with AP-CSI-RS and AP-SRS, where the gNB transmits a resource activation message (710) as described in mechanism 2 above. This message is received and successfully decoded by the UE (730). Since the message indicates the selection of AP-CSI-RS resource subset 1 and AP-SRS resource subset 1, the UE (after a specified or configured delay) assumes that the received AP-CSI-RS and the transmitted AP-SRS will be based on the resource subsets indicated by the joint activation message. When the gNB requests an A-CSI report from the UE via UL-related DCI (720), it transmits the AP-CSI-RS based on the selection from AP-CSI-RS resource subset 1 (a further selection from the N resources can be pre-configured, signaled dynamically via a separate mechanism, or signaled dynamically using the same DCI). When the UE receives this UL-related DCI, it measures the transmitted AP-CSI-RS (740). Then, the UE reports the calculated A-CSI based on AP-SRS resource subset 1 indicated in the activation message and transmits the AP-SRS in the same time slot / subframe (750).

[0137] For the second component (i.e., CSI-RS assisted UL CSI acquisition), SRS can be used for UL channel and UL interference measurements at the gNB / network, where the gNB / network measures the channel and interference via SRS (NZP or ZP or both), calculates the UL CSI, and uses it for link adaptation and scheduling. Thus, the gNB obtains the UL CSI by measuring the SRS. Based on this UL CSI acquisition, a UL grant is allocated to the UE via UL-related DCI, which contains UL transmission parameters such as MCS, transmit PMI, and / or transmit RI. When DL-UL channel reciprocity is feasible, CSI-RS can be used to enhance UL channel measurements (such as providing higher UL channel measurement resolution at the UE). Here, the UE is configured to receive the CSI-RS measured by the UE. Due to channel reciprocity, the DL channel measured via CSI-RS can provide a good approximation of the associated UL channel. For example, this can improve UE UL precoding beyond the resolution given by the TPMI (while the UE still follows the TRI signaled by the gNB). Thus, the UE can be configured with CSI-RS and SRS for the purpose of UL channel acquisition.

[0138] The following embodiments include processes that can be used to configure a UE with CSI-RS and SRS for the purpose of UL channel acquisition. Each embodiment includes at least a link between CSI-RS and SRS, which the UE can assume for UL channel / interference measurement, CSI-RS / SRS timing relationship, and UL CSI calculation. The following embodiments can operate in conjunction with some other UE-specific settings. For example, when the UE is configured for a specific UL transmission scheme or mode (e.g., non-codebook based UL transmission or PMI / TPMI-less UL-related DCI), the UE can also be configured to measure CSI-RS for the purpose of UL CSI acquisition (or generally, UL transmission). Along this line, there are several configuration possibilities to configure the UE to operate as such: 1) the UL transmission scheme is set to operate without PMI or TPMI, and CSI-RS reception / measurement is ON; 2) the UL transmission scheme is set to operate without PMI or TPMI; 3) CSI-RS reception / measurement is ON regardless of whether there is a UL transmission scheme configuration; 4) a set of CSI-RS resources or a CSI-RS resource is configured for the UE and linked to one or more configured SRS resources (e.g., via a correspondence configured by higher layer signaling). This configuration can be performed via higher layer signaling (L2 or L3) or the L1 DL control channel (thus enabling the possibility of dynamic switching).

[0139] In one embodiment (II.A), the number of configured CSI-RS ports can be set to be equal to the number of gNB RX (receive) ports. Optionally, within the CSI-RS resource configuration, a parameter called "function" in this disclosure can be used, which indicates its use for UL CSI acquisition (as opposed to DL CSI acquisition). This parameter can take two values, such as "DLCSI" or "UL CSI". When the CSI-RS is configured in this way (for UL CSI acquisition), the TX (transmission) precoding applied to the CSI-RS (by the gNB) should be the same as (or at least match) the RX (receive) precoding applied to the gNB RX ports (for the purpose of receiving UL transmissions). Here, some type of QCL / correspondence between the SRS and the configured CSI-RS can be used. This correspondence can be part of or supplementary to the parameter "function". Note that if the configured CSI-RS includes K > 1 resources, the number of SRS resources can also include K > 1 resources, where each of the K CSI-RS resources corresponds to one of the K SRS resources. In this case, the correspondence includes K links. Optionally, the number of SRS resources K' ≥ 1 is not necessarily equal to K. In this case, a correspondence between K' ≥ 1 SRS resources and K > 1 CSI-RS resources also needs to be configured.

[0140] The embodiment in the previous paragraph can also be applied to S > 1 CSI-RS resource sets instead of K > 1 CSI-RS resources. Or it can also be applied to S' > 1 SRS resource sets instead of K' > 1 SRS resources.

[0141] Regarding the CSI-RS resource configuration, at least the following mechanisms related to the time-domain behavior are relevant.

[0142] In the first mechanism, when the P / SP-CSI-RS and P / SP-SRS are configured in this way (four possible combinations: P-CSI-RS + P-SRS, P-CSI-RS + SP-SRS, SP-CSI-RS + P-SRS, and SP-CSI-RS + SP-SRS), the relationship between the subframe configuration or slot configuration of these CSI-RS and SRS can be utilized (which includes slot / subframe offset and periodicity). For example, the CSI-RS periodicity can be set to be an integer multiple of the SRS periodicity, while the CSI-RS slot / subframe offset can be defined relative to the SRS slot / subframe offset.

[0143] When configuring SP-CSI-RS and SP-SRS, the SP-CSI-RS can share the same activation / deactivation with the SP-SRS. Sharing the same activation / deactivation means using one resource activation / deactivation message to activate or deactivate the SP-CSI-RS and the SP-SRS. This message can be signaled to the UE via a MAC CE (control element) or L1 DL control signaling (using DL-related or UL-related DCI). When the UE receives an activation message in time slot / subframe n, the UE can assume that starting from time slot / subframe n+D1 (where D1 can be specified, configured via higher layer signaling, or signaled via L1 Dl control signaling), the UE can measure the CSI-RS using the configuration information given in the CSI-RS resource setup (including resource index / index, periodicity, and time slot / subframe offset), and transmit the SRS using the configuration information given in the SRS resource setup (including resource index / index, periodicity, and time slot / subframe offset). Similarly, when the UE receives a deactivation message in time slot / subframe n, the UE can assume that starting from time slot / subframe n+D2 (where D2 can be specified, configured via higher layer signaling, or signaled via L1 Dl control signaling), the UE can stop measuring the CSI-RS using the configuration information given in the CSI-RS resource setup (including resource index / index, periodicity, and time slot / subframe offset), and stop transmitting the SRS using the configuration information given in the SRS resource setup (including resource index / index, periodicity, and time slot / subframe offset). Since the CSI-RS and SRS resource configurations are usually different, the activation / deactivation message can include two resource configuration fields - one for the CSI-RS and the other for the SRS.

[0144] If K'>1 resources are configured for the SRS, the configuration field in the activation / deactivation message can also include an N'-subset selection of the K' resources (1≤N'≤K'). Similarly, if K>1 resources are configured for the CSI-RS, the configuration field in the activation / deactivation message can also include an N-subset selection of the K resources (1≤N≤K). The values of N and N' can be configured via higher layer signaling or via a MAC CE (explicitly or implicitly inferred from the activation message).

[0145] The embodiments in the previous paragraph can also be applied to S>1 CSI-RS resource sets instead of K>1 CSI-RS resources. Or it can also be applied to S'>1 SRS resource sets instead of K'>1 SRS resources.

[0146] The mechanism can be extended when the UE is configured with another SRS (NZP or ZP) for UL interference measurement. In this case, the activation / deactivation message also includes configuration information related to the other SRS. Since this joint activation / deactivation mechanism is similar to the activation / deactivation mechanism of Component I, it can also be shown in Figure 5 as shown.

[0147] The embodiments in the previous paragraph can be applied to non-zero power (NZP) CSI-RS as well as zero power (ZP) CSI-RS. Similarly, it can be applied to non-zero power (NZP) SRS as well as zero power (ZP) SRS.

[0148] In the second mechanism, when the AP-CSI-RS and AP-SRS are configured in such a way that the same DCI is used to trigger the AP-SRS transmission in the same time slot / subframe where there is an AP-CSI-RS. Thus, in an embodiment, when the UE receives UL-related or DL-related DCI that includes a CSI request field and the CSI request field is ON (indicating a request for an A-CSI report) in time slot / subframe n, the UE will report the A-CSI and transmit the AP-SRS in time slot / subframe n + D3 (where D3 can be specified, or configured by higher layer signaling, or signaled by L1 DL control signaling), and the gNB / network receives the A-CSI report and the AP-SRS transmission in the same time slot / subframe.

[0149] As an optional feature of this mechanism, when the UE receives UL-related or DL-related DCI that includes a trigger / request for AP-SRS transmission, an AP-CSI-RS transmission can be present in the same DL time slot / subframe. This AP-SRS trigger can also be accompanied by a DCI field that carries some information about the AP-CSI-RS, such as the selected CSI-RS resource or resource configuration. For this option, multiple K > 1 CSI-RS resources for the AP-CSI-RS in this mechanism can be configured for the UE, and the selected CSI-RS resource is selected from the K configured resources. This selection is indicated and signaled through the DCI field.

[0150] Optionally, instead of having a separate DCI field, this CSI-RS information can be part of the AP-SRS trigger.

[0151] Optionally, the configured CSI-RS resources for the purpose of AP-CSI-RS in this mechanism can be configured semi-statically by higher layer signaling. For this option, only one CSI-RS resource for the purpose of AP-CSI-RS in this mechanism can be configured for the UE. Thus, there is no indication that it needs to be signaled through DCI (L1 control signaling).

[0152] Optionally, multiple K>1 non-zero power (NZP) CSI-RS resources for AP-CSI-RS purposes in this mechanism can be configured for the UE, and the selected CSI-RS resources (i.e., representing the selected state) are associated with the AP-SRS trigger / request state. This association can be configured semi-statically via higher layer signaling (such as RRC) or dynamically (such as via MAC CE). For this option, no signaling indication needs to be signaled via DCI (L1 control signaling) because the selection of the CSI-RS resources for AP-CSI-RS purposes in this mechanism is implicitly related (associated) to the AP-SRS trigger state or the DCI field code point (such as the selection of the SRS resources for AP-SRS purposes in this mechanism).

[0153] Optionally, when the UE is configured with multiple K>1 non-zero power (NZP) CSI-RS resources for AP-CSI-RS purposes in this mechanism and the UE is also configured with K'>1 SRS resources, the association between the AP-SRS trigger state and the NZP CSI-RS resources can also be determined based on predefined association rules. For example, K can be set to be equal to K’, and the k’-th SRS resource (=0, 1, …, K'-1) can be associated with the k-th CSI-RS resource (k = 0, 1, …, K-1), where k = k’. In another example, K can be set to be less than or equal to K’, and the k’-th SRS resource can be associated with the k-th CSI-RS resource, where k = mod(k',K). In another example, K can be set to be equal to K’ / M (where M is an integer, which can be predefined / fixed or configured via higher layer signaling) and the k’-th SRS resource can be associated with the k-th CSI-RS resource, where k = mod(k',K) = mod(k',K’ / M). In another example, K can be set to be equal to K’ / M (where M is an integer, which can be predefined / fixed or configured via higher layer signaling) and the k’-th SRS resource can be associated with the k-th CSI-RS resource, where

[0154] When both AP-CSI-RS and AP-SRS are configured with multiple resources (K>1 resources are configured for CSI-RS and K'>1 resources are configured for SRS), similar to Component I, AP-SRS can share the same activation with AP-CSI-RS. Sharing the same activation means using one resource activation message to perform N subset selection (1≤N≤K) for K resources of AP-CSI-RS and N' subset selection (1≤N'≤K') for K' resources of AP-SRS. This message can be signaled to the UE via MAC CE (control element) or L1DL control signaling (using DL-related or UL-related DCI). When the UE receives the activation message in time slot / subframe n, the UE can assume that starting from time slot / subframe n+D4 (where D1 can be specified, either configured by higher layer signaling or signaled via L1 DL control signaling), it selects the N subset of AP-CSI-RS resources and the N' subset of AP-SRS resources indicated in the resource selection information (in the activation message). Since CSI-RS and SRS resource configurations are usually different, the activation / deactivation message can include two resource configuration fields - one for CSI-RS and the other for SRS.

[0155] The embodiments in the previous paragraph can also be applied to S>1 CSI-RS resource sets instead of K>1 CSI-RS resources. Or it can also be applied to S'>1 SRS resource sets instead of K'>1 SRS resources.

[0156] The embodiments in the previous paragraph can be applied to non-zero power (NZP) CSI-RS as well as zero power (ZP) CSI-RS. Similarly, it can be applied to non-zero power (NZP) SRS as well as zero power (ZP) SRS.

[0157] Since this joint activation / deactivation mechanism is similar to the activation / deactivation mechanism of Component I, it can also be shown in Figure 6 it.

[0158] When both AP-CSI-RS and AP-SRS are configured with multiple resources (K>1 resources are configured for CSI-RS and K'>1 resources are configured for SRS) and AP-CSI-RS is configured for UL CSI acquisition (e.g., "function" is set to "ULCSI"), then the transmission of AP-CSI-RS can be performed as follows. In the time slot / subframe including AP-CSI-RS, the A-CSI trigger is OFF (the CSI request field is set to 0) because AP-CSI-RS is used for UL precoding calculation (performed by the UE due to DL-UL channel reciprocity) and is not applicable to A-CSI report calculation. Regarding AP-SRS, at least the following options can be used.

[0159] In the first option (Opt1), the DCI (UL or DL related) used to trigger AP-SRS transmission is accompanied by AP-CSI-RS transmission in the same DL time slot / subframe. Therefore, the UE can assume that when AP-SRS is triggered (the SRS trigger field is set to 1 or ON), the AP-CSI-RS configured for UL CSI acquisition exists in the same DL time slot / subframe and can be measured by the UE. [[This]]

[0160] As an optional feature of this mechanism, the AP-SRS trigger can also be accompanied by a DCI field that carries some information about the AP-CSI-RS, such as the selected CSI-RS resource or resource configuration. For this option, multiple K>1 CSI-RS resources for the AP-CSI-RS in this mechanism can be configured for the UE, and the selected CSI-RS resource is selected from the K configured resources. This selection is indicated and signaled through the DCI field.

[0161] Optionally, instead of having a separate DCI field, the CSI-RS information can be part of the AP-SRS trigger.

[0162] Optionally, the configured CSI-RS resources for the AP-CSI-RS purpose in this mechanism can be configured semi-statically through higher layer signaling. For this option, one CSI-RS resource can be configured for the UE only for the AP-CSI-RS purpose in this mechanism. Therefore, there is no indication that needs to be signaled through DCI (L1 control signaling).

[0163] Optionally, multiple K>1 CSI-RS resources for the AP-CSI-RS purpose in this mechanism can be configured for the UE, and the selected CSI-RS resource (i.e., indicating the selected state) is associated with the AP-SRS trigger / request state. This association can be configured semi-statically through higher layer signaling (such as RRC) or dynamically (such as through MAC CE). For this option, there is no need to signal an indication through DCI (L1 control signaling) because the selection of the CSI-RS resources for the AP-CSI-RS purpose in this mechanism is implicitly related (associated) to the AP-SRS trigger state or the DCI field code point (such as the selection of the SRS resources for the AP-SRS purpose in this mechanism).

[0164] Optionally, when the UE is configured with multiple K>1 non-zero power (NZP) CSI-RS resources for AP-CSI-RS purposes in this mechanism and the UE is also configured with K'>1 SRS resources, the association between the AP-SRS trigger state and the NZP CSI-RS resources can also be determined based on a predefined association rule. For example, K can be set to be equal to K’, and the k’-th SRS resource (=0, 1, ..., K'-1) can be associated with the k-th CSI-RS resource (k = 0, 1, ..., K-1), where k = k’. In another example, K can be set to be less than or equal to K’, and the k’-th SRS resource can be associated with the k-th CSI-RS resource, where k = mod(k',K). In another example, K can be set to be equal to K’ / M (where M is an integer, which can be predefined / fixed or configured by higher layer signaling) and the k’-th SRS resource can be associated with the k-th CSI-RS resource, where k = mod(k',K) = mod(k',K’ / M). In another example, K can be set to be equal to K’ / M (where M is an integer, which can be predefined / fixed or configured by higher layer signaling) and the k’-th SRS resource can be associated with the k-th CSI-RS resource, where

[0165] In this case, the AP-CSI-RS received by the UE is earlier than the triggered AP-SRS received by the gNB. Therefore, the delay between the received AP-CSI-RS and the received UL grant (which includes UL precoding information such as transmit PMI and transmit RI) may be large.

[0166] The embodiments in the previous paragraph can also be applied to S>1 CSI-RS resource sets instead of K>1 CSI-RS resources. Or it can also be applied to S'>1 SRS resource sets instead of K'>1 SRS resources.

[0167] The embodiments in the previous paragraph can be applied to non-zero power (NZP) CSI-RS as well as zero power (ZP) CSI-RS. Similarly, it can be applied to non-zero power (NZP) SRS as well as zero power (ZP) SRS.

[0168] Figure 8Illustration 800 shows an exemplary operation according to Opt1, where the gNB triggers AP-SRS from UE-k via DCI, and in the same time slot / subframe, transmits AP-CSI-RS (810) configured for UL CSI acquisition purposes. When UE-k receives the DCI, it measures the AP-CSI-RS (820), then reports A-CSI and transmits the AP-SRS in a later time slot / subframe (830). Using the triggered AP-SRS, the gNB performs link adaptation and scheduling, and sends a UL grant (840) including TPMI and TRI in the UL-related DCI to UE-k. Then, UE-k receives the UL grant (850) and uses the signaled TPMI and TRI as well as the AP-CSI-RS (previously received and measured) to derive a UL precoder for the granted UL transmission on the PUSCH (860). In this case, there is a significant latency between the reception of the AP-CSI-RS and the TPMI.

[0169] In the second option (Opt2), the UL-related DCI for the UL grant with the transmitted PMI and RI fields is accompanied by AP-CSI-RS in the same DL time slot / subframe. Thus, there is no link between the AP-SRS trigger and the AP-CSI-RS reception. That is, the AP-SRS can be triggered independently. In this case, the UE can measure the AP-CSI-RS received by the UE to refine the UL precoding information indicated in the transmitted PMI (TPMI) in the same DL time slot / subframe. Thus, there is no latency between the received TPMI and the received AP-CSI-RS.

[0170] In a variant of this Opt2, the TPMI field can indicate a precoder or a precoder group / cluster. In another variant, there may be no TPMI (so only the RI is included in the UL-related DCI). In another variant, when the DCI (UL or DL-related) for triggering the AP-SRS is received in time slot / subframe n (so the AP-SRS is transmitted in subframe n+D), the UL-related DCI for Opt2 is received in subframe n+D+D’ (where D and / or D’ can be specified / fixed or configured). Here, the gNB / network can select or control the value of D’ such that the latency between the AP-SRS reception and the AP-CSI-RS transmission at the gNB / network is small enough.

[0171] Figure 9Illustration 900 shows an exemplary operation according to Opt2, where the gNB triggers an AP-SRS (910) from UE-k via DCI (DL or UL related). When UE-k receives the DCI (920) and transmits the AP-SRS (930), the gNB measures the AP-SRS and uses it for UL CSI acquisition (associated with UE-k). Then, the gNB sends a UL grant (940) including the TPMI and TRI in the UL-related DCI to UE-k. In the same DL time slot / subframe, an AP-CSI-RS configured for UL CSI acquisition is transmitted. When UE-k receives the UL grant and measures the transmitted AP-CSI-RS (950), the UE calculates a UL precoder from the received TPMI and TRI combined with the AP-CSI-RS for the granted UL transmission on the PUSCH (960). Obviously, there is no latency between the AP-CSI-RS and the TPMI. As described above, if there is no link between the A-SRS trigger and the AP-CSI-RS transmission / assignment, the latency between 930 and 940 can be left to the gNB scheduler implementation. Substantially, this depends on how quickly the gNB can measure the AP-SRS and schedule a UL grant for UE-k.

[0172] Any of the above-described variant embodiments can be used independently or in combination with at least one other variant embodiment.

[0173] Figure 10 A flowchart showing an exemplary method 1000 according to an embodiment of the present disclosure, where a UE receives and decodes configuration information for a channel state information reference signal (CSI-RS) and a sounding reference signal (SRS). For example, method 1000 may be performed by UE 116.

[0174] Method 1000 begins with the UE receiving and decoding configuration information for channel state information reference signals (CSI-RS) and sounding reference signals (SRS) (step 1001). Additionally, the UE receives and decodes downlink control information (DCI) including a DCI field for requesting an aperiodic SRS transmission (step 1002). The SRS corresponds to an SRS resource configured by a higher layer, and the number of configured SRS resources is more than one. After the UE decodes the DCI, the UE may continue to receive and measure CSI-RS (step 1003), where the CSI-RS is received in the same downlink time slot as the DCI. The CSI-RS corresponds to a non-zero power (NZP) CSI-RS resource configured by a higher layer. The DCI field includes an aperiodic SRS trigger status associated with the configured SRS resource. The configured NZP CSI-RS resource is measured to calculate a precoder for the SRS, and the SRS is transmitted later (step 1004). The number of configured NZP CSI-RS resources may be one. Optionally, the number of configured NZP CSI-RS resources is more than one, and the association between the SRS trigger status and the configured SRS resource further includes an association with the configured NZP CSI-RS resources.

[0175] Figure 11 A flowchart illustrating an exemplary method 1100 according to an embodiment of the present disclosure, where a BS generates configuration information for channel state information reference signals (CSI-RS) and sounding reference signals (SRS) for a UE (labeled UE-k). For example, method 1100 may be performed by BS 102.

[0176] Method 1100 starts with the BS generating configuration information for channel state information reference signals (CSI-RS) and sounding reference signals (SRS) for a UE (referred to as UE-k), as well as downlink control information (DCI) including a DCI field for requesting an aperiodic SRS transmission (step 1101). The BS then continues to transmit the configuration information, DCI, and CSI-RS to UE-k via a downlink (DL) channel (step 1102). The CSI-RS is transmitted in the same downlink time slot as the DCI and corresponds to a non-zero power (NZP) CSI-RS resource configured by a higher layer. The SRS corresponds to an SRS resource configured by a higher layer, and the number of configured SRS resources is more than one. The DCI field includes an aperiodic SRS trigger state associated with the configured SRS resource. The NZP CSI-RS resource is measured to calculate a precoder for the transmitted SRS. The number of configured NZP CSI-RS resources can be one. Optionally, the number of configured NZP CSI-RS resources is more than one, and the association between the SRS trigger state and the configured SRS resources also includes an association with the configured NZP CSI-RS resources. The BS continues to receive the requested aperiodic SRS from UE-k (step 1103).

[0177] Although Figure 10 and Figure 11 respectively show examples of methods for receiving configuration information and configuring a UE, various changes can be made to Figure 10 and Figure 11 For example, although shown as a series of steps, the various steps in each figure can overlap, occur in parallel, occur in a different order, occur multiple times, or not be performed in one or more embodiments.

[0178] Although the present disclosure has been described with exemplary embodiments, those skilled in the art can propose various changes and modifications. The present disclosure is intended to cover such changes and modifications that fall within the scope of the appended claims.

Claims

1. A user equipment (UE) operating in a wireless communication system, the UE comprising: a transceiver; and a processor operably connected to the transceiver and configured to: receive from a base station configuration information on non-zero power channel state information reference signal (CSI-RS) resources associated with an aperiodic sounding reference signal (SRS), receive from the base station downlink control information including aperiodic SRS triggering information, receive from the base station non-zero power CSI-RS associated with the non-zero power CSI-RS resources, wherein the non-zero power CSI-RS resources are identified based on the aperiodic SRS triggering information, identify an uplink precoder for the aperiodic SRS based on the received non-zero power CSI-RS, and transmit the aperiodic SRS to the base station, wherein when the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS triggering information and the non-zero power CSI-RS are received in the same time slot.

2. The UE according to claim 1, wherein the number of non-zero power CSI-RS resources is one of one or more SRS resources corresponding to the aperiodic SRS.

3. The UE according to claim 1, wherein the processor is further configured to: receive from the base station information configuring an uplink transmission without a transmit precoding matrix indicator (TPMI).

4. The UE according to claim 1, wherein the configuration information on the non-zero power CSI-RS resources is received via higher layer signaling.

5. The UE according to claim 3, wherein the processor is further configured to: receive from the base station an uplink grant without a TPMI, and transmit data to the base station on a physical uplink shared channel (PUSCH) based on the uplink grant.

6. A base station operating in a wireless communication system, the base station comprising: a transceiver; and a processor operably connected to the transceiver and configured to: transmit to a user equipment (UE) configuration information on non-zero power channel state information reference signal (CSI-RS) resources associated with an aperiodic sounding reference signal (SRS), transmit to the UE downlink control information including aperiodic SRS triggering information, transmit to the UE non-zero power CSI-RS associated with the non-zero power CSI-RS resources, wherein the non-zero power CSI-RS resources are associated with the aperiodic SRS triggering information, and receive from the UE an aperiodic SRS based on an uplink precoder, wherein when the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS triggering information and the non-zero power CSI-RS are in the same time slot.

7. The base station according to claim 6, wherein the number of non-zero power CSI-RS resources is one of one or more SRS resources corresponding to the aperiodic SRS.

8. The base station according to claim 6, wherein the processor is further configured to: transmit to the UE information configuring an uplink transmission without a transmit precoding matrix indicator (TPMI).

9. The base station according to claim 6, wherein the configuration information on the non-zero power CSI-RS resources is transmitted via higher layer signaling.

10. The base station according to claim 8, wherein the processor is further configured to: transmit an uplink grant without a TPMI to the UE, and receive data associated with a physical uplink shared channel PUSCH from the UE.

11. A method performed by a user equipment UE operating in a wireless communication system, the method comprising: receiving, from a base station, configuration information about a non-zero power channel state information reference signal CSI-RS resource associated with an aperiodic sounding reference signal SRS; receiving, from the base station, downlink control information including aperiodic SRS trigger information; receiving, from the base station, a non-zero power CSI-RS associated with the non-zero power CSI-RS resource, wherein the non-zero power CSI-RS resource is identified based on the aperiodic SRS trigger information; identifying an uplink precoder for the aperiodic SRS based on the received non-zero power CSI-RS; and transmitting the aperiodic SRS to the base station, wherein when the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS trigger information and the non-zero power CSI-RS are received in the same time slot.

12. The method according to claim 11, wherein the number of non-zero power CSI-RS resources is one of one or more SRS resources corresponding to the aperiodic SRS.

13. The method according to claim 11, further comprising: receiving, from the base station, information configuring an uplink transmission without a transmission precoding matrix indicator TPMI.

14. The method according to claim 11, wherein the configuration information about the non-zero power CSI-RS resource is received via higher layer signaling.

15. The method according to claim 13, further comprising: receiving, from the base station, an uplink grant without a TPMI; and transmitting data to the base station on a physical uplink shared channel PUSCH based on the uplink grant.

16. A method performed by a base station operating in a wireless communication system, the method comprising: transmitting, to a user equipment UE, configuration information about a non-zero power channel state information reference signal CSI-RS resource associated with an aperiodic sounding reference signal SRS; transmitting, to the UE, downlink control information including aperiodic SRS trigger information; transmitting, to the UE, a non-zero power CSI-RS associated with the non-zero power CSI-RS resource, wherein the non-zero power CSI-RS resource is associated with the aperiodic SRS trigger information; and receiving, from the UE, an aperiodic SRS based on an uplink precoder, wherein when the non-zero power CSI-RS is an aperiodic CSI-RS, the aperiodic SRS trigger information and the non-zero power CSI-RS are in the same time slot.

17. The method according to claim 16, wherein the number of non-zero power CSI-RS resources is one of one or more SRS resources corresponding to the aperiodic SRS.

18. The method according to claim 16, further comprising: transmitting, to the UE, information configuring an uplink transmission without a transmission precoding matrix indicator TPMI.

19. The method according to claim 16, wherein configuration information about non-zero power CSI-RS resources is transmitted via higher layer signaling.

20. The method according to claim 18, further comprising: transmitting an uplink grant without a TPMI to the UE, and receiving data associated with a physical uplink shared channel PUSCH from the UE.

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