Method and apparatus for implementing uplink mimo

Abstract

This disclosure relates to a pre-fifth-generation (5G) or 5G communication system intended to support higher data rates than fourth-generation (4G) communication systems such as Long Term Evolution (LTE). Methods and apparatus for implementing uplink multiple-input multiple-output (MIMO) are provided. A user equipment (UE) includes a transceiver and a processor operatively connected to the transceiver. The transceiver is configured to receive a UL license for uplink (UL) transmission. The processor is configured to decode a precoding information field in downlink control information (DCI) associated with the UL license. The precoding information field includes at least one precoding matrix indicator (PMI) corresponding to a plurality of precoders. The transceiver is further configured to precode a data stream according to the precoder indicated by the precoding information field and transmit the precoded data stream on a UL channel.

Description

Technical Field

[0001] To meet the increased demand for wireless data traffic since the deployment of 4G (4th generation) communication systems, efforts have been made to develop improved 5G (5th generation) or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems".

[0002] It is believed that 5G communication systems will be implemented in millimeter-wave (mmWave) bands (e.g., 60GHz band) to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance, beamforming technology, massive MIMO technology, full-dimensional MIMO (FD-MIMO) technology, array antenna technology, analog beamforming technology, and massive MIMO technology are discussed in 5G communication systems.

[0003] In addition, research and development is underway in 5G communication systems to improve system networks based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and receiver interference cancellation.

[0004] In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coding and modulation (ACM), while filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) have been developed as advanced access technologies.

[0005] This disclosure generally relates to methods for implementing uplink multiple-input multiple-output (MIMO). These methods can be used when a user equipment is equipped with multiple transmit antennas and transmit-receive units. Background Technology

[0006] Wireless communication is one of the most successful innovations in modern history. The demand for wireless data traffic is rapidly increasing due to the growing popularity of smartphones and other mobile data devices (such as tablets, notebook computers, netbooks, e-book readers, and machine-type devices) among consumers and businesses. To meet this high growth in mobile data traffic and support new applications and deployments, improvements in wireless interface efficiency and coverage are crucial.

[0007] Mobile devices or user equipment can measure the quality of the downlink channel and report this quality to the base station, enabling the determination of whether various parameters should be adjusted during communication with the mobile device. Existing channel quality reporting processing in wireless communication systems is insufficient to handle the reporting of channel state information associated with large two-dimensional array transmission antennas, or antenna array geometries typically designed to accommodate a large number of antenna elements. Summary of the Invention

[0008] Various embodiments of this disclosure provide methods and apparatus for CSI reporting.

[0009] In one embodiment, a user equipment (UE) is provided. The UE includes a transceiver and a processor operatively connected to the transceiver. The transceiver is configured to receive a UL license for uplink (UL) transmission. The processor is configured to decode a precoding information field in downlink control information (DCI) associated with the UL license. The precoding information field includes at least one precoding matrix indicator (PMI) corresponding to a plurality of precoders. The transceiver is also configured to precode a data stream according to the precoder indicated by the precoding information field and transmit the precoded data stream on a UL channel.

[0010] In another embodiment, a base station (BS) is provided. The BS includes a processor and a transceiver operatively connected to the processor. The processor is configured to generate a precoded information field in a DCI and to generate a UL license for UL transmission to a UE. The transceiver is configured to transmit the UL license to the UE via a downlink (DL) channel. The DCI is associated with the UL license, and the precoded information field includes at least one PMI corresponding to a plurality of precoders.

[0011] In another embodiment, a method for operating a UE is provided. The method includes the UE receiving a UL license for UL transmission. The method further includes the UE decoding a precoding information field in a DCI associated with the UL license, wherein the precoding information field includes at least one PMI corresponding to a plurality of precoders. The method also includes the UE precoding a data stream according to a precoder indicated by the precoding information field. Finally, the method includes the UE transmitting the precoded data stream on a UL channel.

[0012] In another embodiment, a method for operating a base station (BS) is provided. The method includes: generating a precoding information field in downlink control information (DCI); generating a UL license for uplink (UL) transmission to a user equipment (UE); and transmitting the UL license to the UE via a downlink (DL) channel, wherein the DCI is associated with the UL license, and the precoding information field includes at least one precoding matrix indicator (PMI) corresponding to a plurality of precoders.

[0013] This disclosure relates to a pre-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).

[0014] Other technical features will be readily apparent to those skilled in the art from the following figures, description and claims.

[0015] Before proceeding with the detailed description below, it may be advantageous to define certain words and phrases used throughout this patent document. The term “connection” and its derivatives refer to any direct or indirect communication between two or more elements, regardless of whether those elements are physically in contact with each other. The terms “transmit,” “receive,” and “communicate,” and their derivatives encompass both direct and indirect communication. The terms “include” and “comprise,” and their derivatives, mean to include rather than to limit. The term “or” is inclusive, meaning and / or. The phrase “associated with” and its derivatives mean to include, to be contained within, to be interconnected with, to contain, to be included in, to be connected to or connected with, to be coupled to or connected with, to be communicable with, to cooperate with, to interleave, to juxtapose, to be close to, to be bonded to or bonded with, to have, to possess the attributes of, to have a relationship or a relationship with, or the like. The term “controller” means any device, system, or part thereof that controls at least one operation. Such a device may be implemented as hardware or a combination of hardware and software and / or firmware. The functionality associated with any particular controller can be centralized or distributed, local or remote. The phrase "at least one" when used with a list of items means that different combinations of one or more of the listed items are available, and that only one item from 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 and B and C.

[0016] Furthermore, the various functions described below may be implemented or supported by one or more computer programs, each of which is formed by computer-readable program code and implemented in a computer-readable medium. The terms "application" and "program" refer to one or more computer programs, software components, instruction sets, processes, functions, objects, classes, examples, associated data, or portions thereof that are suitable for implementation in 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 disc (CD), digital video disc (DVD), or any other type of storage. "Non-transitory" computer-readable media excludes wired, wireless, optical, or other communication links that transmit transient electrical or other signals. Non-transitory computer-readable media includes media in which data can be permanently stored and media in which data can be stored and later rewritten, such as rewritable optical discs or erasable memory devices.

[0017] Definitions of certain words and phrases are provided throughout this patent document. Those skilled in the art will understand that, in many, if not most, cases, these definitions apply to the prior and future use of the words and phrases defined therein. Attached Figure Description

[0018] To gain a more complete understanding of this disclosure and its advantages, the following description is now made with reference to the accompanying drawings, in which the same reference numerals denote the same parts:

[0019] Figure 1 Exemplary wireless networks according to various embodiments of this disclosure are shown;

[0020] Figure 2A and Figure 2B Exemplary wireless transmission paths and wireless reception paths according to various embodiments of this disclosure are shown;

[0021] Figure 3A Exemplary user equipment according to various embodiments of this disclosure is shown;

[0022] Figure 3B Exemplary base stations (BSs) according to various embodiments of the present disclosure are shown;

[0023] Figure 4 An exemplary beamforming architecture is shown, in which one CSI-RS port is mapped to a large number of analog controlled antenna elements;

[0024] Figure 5Exemplary operations of dynamic and semi-dynamic precoded transmissions according to embodiments of this disclosure are shown;

[0025] Figure 6 Exemplary downlink (DL) signaling for subband precoding and UE processing for interpreting precoding information DCI fields are illustrated according to embodiments of this disclosure;

[0026] Figure 7 Several exemplary DL signaling schemes for supporting subband precoding according to some embodiments of the present disclosure are shown;

[0027] Figure 8 Another exemplary DL signaling scheme for supporting subband precoding according to an embodiment of this disclosure is shown;

[0028] Figure 9 A flowchart of an exemplary method according to an embodiment of the present disclosure is shown, wherein a UE receives a UL license for UL transmission, the UL license for UL transmission including pre-encoded information fields associated with a plurality of pre-encoded encoders.

[0029] Figure 10 A flowchart of an exemplary method according to an embodiment of the present disclosure is shown, wherein the BS generates a precoded information field having at least one PMI for the UE (labeled UE-k). Detailed Implementation

[0030] The following discussion Figures 1 to 10 The various embodiments used to describe the principles of this disclosure in this patent document are merely exemplary and should not be construed in any way as limiting the scope of this disclosure. Those skilled in the art will understand that the principles of this disclosure can be implemented in any suitably arranged wireless communication system.

[0031] List of acronyms

[0032] 2D: Two-dimensional

[0033] MIMO: Multiple Input Multiple Output

[0034] SU-MIMO: Single-user MIMO

[0035] MU-MIMO: Multi-user MIMO

[0036] 3GPP: Third Generation Partnership Project

[0037] LTE: Long Term Evolution

[0038] UE: User Equipment

[0039] eNB: Evolved Node B or "eNB"

[0040] BS: Base Station

[0041] DL: Downlink

[0042] UL: Uplink

[0043] CRS: Cell-Specific Reference Signal

[0044] DMRS: Demodulation reference signal

[0045] SRS: Detection Reference Signal

[0046] UE-RS: UE-specific reference signal

[0047] CSI-RS: Channel State Information Reference Signal

[0048] SCID: Scrambling Identity

[0049] MCS: Modulation and Coding Scheme

[0050] RE: Resource Elements

[0051] CQI: Channel Quality Information

[0052] PMI: Precoding Matrix Indicator

[0053] RI: Rank Indicator

[0054] MU-CQI: Multi-User CQI

[0055] CSI: Channel State Information

[0056] CSI-IM: CSI Interference Measurement

[0057] CoMP: Coordinating Multiple Points

[0058] DCI: Downlink Control Information

[0059] UCI: Uplink Control Information

[0060] PDSCH: Physical Downlink Shared Channel

[0061] PDCCH: Physical Downlink Control Channel

[0062] PUSCH: Physical Uplink Shared Channel

[0063] PUCCH: Physical Uplink Control Channel

[0064] PRB: Physical Resource Block

[0065] RRC: Radio Resource Control

[0066] AoA: Angle of Arrival

[0067] AoD: Departure Angle

[0068] The following documents and standards are incorporated herein by reference as if set forth in their entirety: 3GPP Technical Specification (TS) 36.211, version 12.4.0, “E-UTRA, Physical Channels and Modulation” (“Reference 1”); 3GPP TS 36.212, version 12.3.0, “E-UTRA, Multiplexing and Channel Coding” (“Reference 2”); 3GPP TS 36.213, version 12.4.0, “E-UTRA, Physical Layer Processing” (“Reference 3”); 3GPP TS 36.321, version 12.4.0, “E-UTRA, Media Access Control (MAC) Protocol Specification” (“Reference 4”); and 3GPP TS 36.331, version 12.4.0, “E-UTRA, Radio Resource Control (RRC) Protocol Specification” (“Reference 5”).

[0069] To meet the increased demand for wireless data traffic since the deployment of 4G (4th generation) communication systems, efforts have been made to develop improved 5G (5th generation) or pre-5G communication systems. Therefore, 5G or pre-5G communication systems are also referred to as "super 4G networks" or "post-LTE systems".

[0070] It is believed that 5G communication systems will be implemented in millimeter-wave (mmWave) bands (e.g., 60GHz band) to achieve higher data rates. To reduce radio wave propagation loss and increase transmission distance, beamforming technology, massive MIMO technology, full-dimensional MIMO (FD-MIMO) technology, array antenna technology, analog beamforming technology, and massive MIMO technology are discussed in 5G communication systems.

[0071] In addition, research and development is underway in 5G communication systems to improve system networks based on advanced small cells, cloud radio access networks (RAN), ultra-dense networks, device-to-device (D2D) communication, wireless backhaul, mobile networks, cooperative communication, cooperative multipoint (CoMP), and receiver interference cancellation.

[0072] In 5G systems, hybrid FSK and QAM modulation (FQAM) and sliding window superposition coding (SWSC) have been developed as advanced coding and modulation (ACM), while filter bank multicarrier (FBMC), non-orthogonal multiple access (NOMA) and sparse code multiple access (SCMA) have been developed as advanced access technologies.

[0073] Figure 1 An exemplary wireless network 100 according to various embodiments of the present disclosure is shown. Figure 1The 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 this disclosure.

[0074] Wireless network 100 includes base station (BS) 101, BS 102, and BS 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 network). Alternative terms such as "eNB" (enhanced Node B) or "gNB" (general Node B) may be used instead of "BS," depending on the network type. Depending on the network type, other well-known terms such as "base station" or "access point" may be used instead of "gNB" or "BS." For convenience, the terms "gNB" and "BS" are used in this patent document to refer to network infrastructure components that provide wireless access to remote terminals. Furthermore, depending on the network type, other well-known terms such as "user equipment" or "UE" may be used instead of "mobile station," "user 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 a remote wireless device that wirelessly accesses a gNB, whether the UE is a mobile device (such as a mobile phone or a smartphone) or is generally considered to be a fixed device (such as a desktop computer or a vending machine).

[0075] gNB 102 provides wireless broadband access to network 130 to a first plurality of user equipments (UEs) within its coverage area 120. 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 organization (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, wireless laptop, wireless PDA, etc.). gNB 103 provides wireless broadband access to network 130 to a second plurality of UEs within its coverage area 125. The second plurality of UEs includes UE 115 and UE 116. In some embodiments, one or more of gNBs 101 to gNB 103 may communicate with each other and with UEs 111 to UE 116 using 5G, LTE, LTE-A, WiMAX, or other advanced wireless communication technologies.

[0076] The dashed lines indicate the approximate extent of coverage areas 120 and 125, which are shown as approximately circular for illustrative and explanatory purposes. It should be clearly understood that, depending on the configuration of the gNB and variations in the radio environment related to natural and man-made obstacles, the coverage areas associated with the gNB (such as coverage areas 120 and 125) may have other shapes, including irregular shapes.

[0077] As described in more detail below, one or more of gNB 101, gNB 102, and gNB 103 transmit measurement reference signals to UEs 111 to UEs 116 and configure UEs 111 to UEs 116 for CSI reporting, as described in embodiments of this disclosure. In various embodiments, one or more of UEs 111 to UEs 116 receive and transmit transmission schemes or precoding information for signaling in uplink clearances accordingly.

[0078] Although Figure 1 An example of a wireless network 100 is shown, but it is possible to modify it. Figure 1 Various modifications can be made. For example, the wireless network 100 can be arranged in any suitable manner, including any number of gNBs and any number of UEs. Furthermore, gNB 101 can communicate directly with any number of UEs and provide those UEs with wireless broadband access to network 130. Similarly, each of gNBs 102 to gNB 103 can communicate directly with network 130 and provide UEs with direct wireless broadband access to network 130. Additionally, gNBs 101, 102, and / or 103 can provide access to other or additional external networks (such as external telephone networks or other types of data networks).

[0079] Figure 2A and Figure 2B Exemplary wireless transmit and receive paths according to this disclosure are shown. In the following description, transmit path 200 may be described as being implemented in a gNB (such as gNB 102), while receive path 250 may be described as being implemented in a UE (such as UE 116). However, it should be understood that receive path 250 may be implemented in a gNB, and transmit path 200 may be implemented in a UE. In some embodiments, as described in embodiments of this disclosure, receive path 250 is configured to receive and transmit transmission schemes or precoded signals of signaling in an uplink clearance.

[0080] The transmit path 200 includes a channel coding and modulation block 205, a serial-to-parallel (S to P) block 210, an N-sized inverse fast Fourier transform (IFFT) block 215, a parallel-to-serial (P to S) block 220, a cyclic prefix addition block 225, and an up-converter (UC) 230. The receive path 250 includes a down-converter (DC) 255, a cyclic prefix removal block 260, a serial-to-parallel (S to P) block 265, an N-sized fast Fourier transform (FFT) block 270, a parallel-to-serial (P to S) block 275, and a channel decoding and demodulation block 280.

[0081] In transmit path 200, channel coding and modulation block 205 receives a set of information bits, applies coding (such as convolution, turbine, 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 generate a frequency-domain modulated symbol sequence. Serial-to-parallel block 210 transforms (e.g., demultiplexes) the serially modulated symbols into parallel data to generate N parallel symbol streams, where N is the IFFT / FFT size used in gNB 102 and UE 116. N-size IFFT block 215 performs IFFT operations on the N parallel symbol streams to generate a time-domain output signal. Parallel-to-serial block 220 transforms (e.g., multiplexes) the parallel time-domain output symbols from N-size IFFT block 215 to generate a serial time-domain signal. "Add Cyclic Prefix" block 225 inserts a cyclic prefix into the time-domain signal. Upconverter 230 modulates (as above) the output of "add cyclic prefix" block 225 to an RF frequency for transmission via a wireless channel. The signal may also be filtered at baseband before being converted to the RF frequency.

[0082] The transmitted RF signal reaches UE 116 from gNB 102 after passing through the wireless channel, and at UE 116, the operation is performed inversely to that at gNB 102. Downconverter 255 downconverts the received signal to baseband frequency, and cyclic prefix removal block 260 removes the cyclic prefix to generate a serial time-domain baseband signal. Serial-to-parallel block 265 transforms the time-domain baseband signal into a parallel time-domain signal. N-size FFT block 270 performs an FFT algorithm to generate N parallel frequency-domain signals. Parallel-to-serial block 275 transforms the parallel frequency-domain signals into a sequence of modulated data symbols. Channel decoding and demodulation block 280 demodulates and decodes the modulated symbols to recover the original input data stream.

[0083] As described in more detail below, transmit path 200 or receive path 250 may execute signaling for CSI reporting. Each of gNBs 101 to gNBs 103 may be implemented as transmit path 200 simulating transmission to UEs 111 to UEs 116 in the downlink, and may be implemented as receive path 250 simulating reception from UEs 111 to UEs 116 in the uplink. Similarly, each of UEs 111 to UEs 116 may be implemented as transmit path 200 simulating transmission to gNBs 101 to gNBs 103 in the uplink, and may be implemented as receive path 250 simulating reception from gNBs 101 to gNBs 103 in the downlink.

[0084] Figure 2A and Figure 2B Each of the components can be implemented using only hardware or a combination of hardware and software / firmware. As a concrete example, Figure 2A and Figure 2B At least some of the components can be implemented in software, while others can be implemented using configurable hardware or a combination of software and configurable hardware. For example, FFT block 270 and IFFT block 215 can be implemented as configurable software algorithms, where the value of N can be changed depending on the implementation.

[0085] Furthermore, although described as using FFT and IFFT, this is merely an exemplary approach and should not be construed as limiting the scope of this disclosure. Other types of transforms, such as the Discrete Fourier Transform (DFT) and Inverse Discrete Fourier Transform (IDFT) functions, may be used. It should be understood that for DFT and IDFT functions, the value of variable N can be any integer (such as 1, 2, 3, 4, etc.), while for FFT and IFFT functions, the value of variable N can be any integer that is a power of 2 (such as 1, 2, 4, 8, 16, etc.).

[0086] Although Figure 2A and Figure 2B Examples of wireless transmit and receive paths are shown, but more details can be found on the wireless transmit and receive paths. Figure 2A and Figure 2B Make various changes. For example, make them combinable, further subdivided, or omitted. Figure 2A and Figure 2B It contains various components, and additional components can be added according to specific needs. Furthermore, Figure 2A and Figure 2B This is intended to illustrate examples of the types of transmit and receive paths that can be used in wireless networks. Other suitable architectures can be used to support wireless communication in wireless networks.

[0087] Figure 3A An exemplary UE 116 according to this disclosure is shown. Figure 3AThe implementation of UE 116 shown is for illustrative purposes only, and Figure 1 UEs 111 to UE 115 may have the same or similar configurations. However, UEs have a wide variety of configurations, and Figure 3A This disclosure is not intended to limit the scope to any particular implementation of the UE.

[0088] UE 116 includes an antenna 305, a radio frequency (RF) transceiver 310, a transmit (TX) processing circuitry 315, a microphone 320, and a receive (RX) processing circuitry 325. UE 116 also includes a speaker 330, a processor 340, an input / output (I / O) interface (IF) 345, an input 350, a display 355, and a memory 360. The memory 360 includes an operating system (OS) program 361 and one or more applications 362.

[0089] RF transceiver 310 receives incoming RF signals transmitted by the gNB of network 100 from antenna 305. RF transceiver 310 down-converts the incoming RF signals to generate intermediate frequency (IF) or baseband signals. The IF or baseband signal is sent to RX processing circuitry 325, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signal. RX processing circuitry 325 sends the processed baseband signal to speaker 330 (e.g., for voice data) or to processor 340 for further processing (e.g., for web browsing data).

[0090] The TX processing circuit 315 receives analog or digital voice data from the microphone 320 or other outgoing baseband data (such as network data, email, or interactive video game data) from the processor 340. The TX processing circuit 315 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. The RF transceiver 310 receives the processed outgoing baseband or IF signal from the TX processing circuit 315 and upconverts the baseband or IF signal into an RF signal transmitted via the antenna 305.

[0091] Processor 340 may include one or more processors or other processing devices and executes OS program 361 stored in memory 360 to control the overall operation of UE 116. For example, processor 340 may control the reception of forward channel signals and the transmission of reverse channel signals by RF transceiver 310, RX processing circuitry 325, and TX processing circuitry 315 according to well-known principles. In some embodiments, processor 340 includes at least one microprocessor or microcontroller.

[0092] As described in embodiments of this disclosure, processor 340 is also capable of executing other processes and programs residing in memory 360, such as operations for CQI measurements and reports for the system described in embodiments of this disclosure. Processor 340 may move data into or out of memory 360 as needed to perform processing. In some embodiments, processor 340 is configured to execute application 362 based on OS program 361 or in response to signals received from a gNB or operator. Processor 340 is also coupled to I / O interface 345, which provides UE 116 with the ability to connect to other devices, such as laptop computers and handheld computers. I / O interface 345 is the communication path between these accessories and processor 340.

[0093] The processor 340 is also connected to the input 350 (e.g., keyboard, touchscreen, buttons, etc.) and the display 355. The operator of the UE 116 can use the input 350 to input data into the UE 116. The display 355 may be an LCD or other display capable of displaying text and / or at least limited graphics from a website.

[0094] 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).

[0095] As described in more detail below, UE 116 can perform signaling and calculations for CSI reporting. Although Figure 3A An example of UE 116 is shown, but it is possible to modify it. Figure 3A Make various changes. For example, make them combinable, further subdivided, or omitted. Figure 3A The processor 340 contains various components, and additional components can be added as needed. As a specific example, the processor 340 can be divided into multiple processors, such as one or more central processing units (CPUs) and one or more graphics processing units (GPUs). Furthermore, although... Figure 3A The UE 116 is shown configured as a mobile phone or smartphone, but the UE can be configured to operate as other types of mobile or fixed devices.

[0096] Figure 3B An exemplary gNB 102 according to this disclosure is shown. Figure 3B The embodiment of gNB 102 shown is for illustrative purposes only, and Figure 1 Other gNBs may have the same or similar configurations. However, gNBs have a wide variety of configurations, and Figure 3B This disclosure is not intended to limit the scope to any particular implementation of gNB. gNB 101 and gNB 103 may include the same or similar structures as gNB 102.

[0097] like Figure 3B As shown, gNB 102 includes multiple antennas 370a to 370n, multiple RF transceivers 372a to 372n, transmit (TX) processing circuitry 374, and receive (RX) processing circuitry 376. In some embodiments, one or more of the multiple antennas 370a to 370n include a 2D antenna array. gNB 102 also includes a controller / processor 378, a memory 380, and a backhaul or network interface 382.

[0098] RF transceivers 372a to 372n receive incoming RF signals, such as signals transmitted by the UE or other gNBs, from antennas 370a to 370n. 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 RX processing circuitry 376, which generates a processed baseband signal by filtering, decoding, and / or digitizing the baseband or IF signals. RX processing circuitry 376 sends the processed baseband signal to controller / processor 378 for further processing.

[0099] TX processing circuitry 374 receives analog or digital data (such as voice data, network data, email, or interactive video game data) from controller / processor 378. TX processing circuitry 374 encodes, multiplexes, and / or digitizes the outgoing baseband data to generate a processed baseband or IF signal. RF transceivers 372a to 372n receive the processed outgoing baseband or IF signal from TX processing circuitry 374 and up-convert the baseband or IF signal into an RF signal transmitted via antennas 370a to 370n.

[0100] The controller / processor 378 may include one or more processors or other processing devices that control the overall operation 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, based on well-known principles. The controller / processor 378 may also support additional functions, such as more advanced wireless communication capabilities. In some embodiments, the controller / processor 378 includes at least one microprocessor or microcontroller.

[0101] The controller / processor 378 is also capable of executing programs and other processes, such as an operating system, residing in the memory 380. As described in embodiments of this disclosure, the controller / processor 378 is also capable of supporting channel quality measurement and reporting for systems with 2D antenna arrays. In some embodiments, the controller / processor 378 supports inter-entity communication, such as web RTC. The controller / processor 378 can move data into or out of the memory 380 as needed for processing.

[0102] The controller / processor 378 is also coupled to the 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 over a network. Interface 382 can support communication via any suitable wired or wireless connection. For example, when the gNB 102 is implemented as part of a cellular communication system (such as supporting 5G or new radio access technologies or one of NR, LTE, or LTE-A), interface 382 can 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, interface 382 can allow the gNB 102 to communicate with a larger network (such as the Internet) via a wired or wireless local area network or via a wired or wireless connection. Interface 382 includes any suitable architecture that supports communication via wired or wireless connections (such as Ethernet or RF transceivers).

[0103] Memory 380 is coupled to controller / processor 378. A portion of memory 380 may include RAM, and another portion of memory 380 may include flash memory or other ROM. In some embodiments, the memory stores multiple instructions, such as a BIS algorithm. The multiple instructions are configured to cause controller / processor 378 to perform BIS processing and decode the received signal after subtracting at least one interference signal determined by the BIS algorithm.

[0104] As described in more detail below, the transmit and receive paths of the gNB 102 (implemented using RF transceivers 372a to 372n, TX processing circuitry 374, and / or RX processing circuitry 376) perform configuration and signaling for CSI reporting.

[0105] Although Figure 3B An example of gNB 102 is shown, but it is possible to modify it. Figure 3B Various changes can be made. For example, gNB 102 may include... Figure 3AEach component can be any number shown. As a particular example, an access point may include multiple interfaces 382, ​​and a controller / processor 378 may support routing functionality to route data between different network addresses. As another particular example, although shown as a single example including TX processing circuitry 374 and a single example including RX processing circuitry 376, gNB 102 may include multiple examples of each (e.g., one per RF transceiver).

[0106] Rel.13 LTE supports up to 16 CSI-RS antenna ports, enabling 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 a single CSI-RS port. Furthermore, Rel.14 LTE will support up to 32 CSI-RS ports. For next-generation cellular systems such as 5G, the maximum number of CSI-RS ports is expected to remain more or less the same.

[0107] For millimeter-wave bands, although the number of antenna elements can be greater for a given form factor, however... Figure 4 As shown in implementation 400, the number of CSI-RS ports, corresponding to the number of digital precoding ports, tends to be limited by hardware constraints (such as the feasibility of installing a large number of ADCs / DACs at millimeter-wave frequencies). In this case, a CSI-RS port is mapped to a large number of antenna elements that can be controlled by a set of analog phase shifters 401. A 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 wider range of angles (420) by changing the set of phase shifters on symbols or subframes. The number of subarrays (equal to the number of RF chains) corresponds to the number of CSI-RS ports N. CSI-PORT (N CSI-端口 Same. Digital beamforming unit 410 spans N CSI-PORT The analog beams are linearly combined to further increase the precoding gain. While the analog beams are broadband (and therefore not frequency selective), the digital precoding can vary across frequency subbands or resource blocks.

[0108] Effective design of CSI-RS is crucial for digital precoding. To this end, Rel.13 LTE supports three types of CSI reporting mechanisms corresponding to three types of CSI-RS measurement behaviors: 1) "Class A" CSI reporting for non-precoded CSI-RS, 2) "Class B" reporting with K=1 CSI-RS resources corresponding to UE-specific beamforming CSI-RS, and 3) "Class B" reporting with K>1 CSI-RS resources corresponding to cell-specific beamforming CSI-RS. For non-precoded (NP) CSI-RS, a cell-specific one-to-one mapping between CSI-RS ports and TXRUs is utilized. Here, different CSI-RS ports have the same wide beamwidth and orientation, and therefore typically cover the cell width. For beamforming CSI-RS, (cell-specific or UE-specific) beamforming operations are applied to non-zero power (NZP) CSI-RS resources (which include multiple ports). Here, (at least at a given time / frequency) the CSI-RS port has a narrow beamwidth and therefore no cell-width coverage, and (at least from the gNB perspective) at least some combinations of CSI-RS port resources have different beam orientations.

[0109] In scenarios where DL long-term channel statistics can be measured via the UL signal at the serving gNB, UE-specific BF CSI-RS can be readily used. This is generally feasible when the UL-DL duplex distance is sufficiently small. However, when this condition is not met, some UE feedback is used by the gNB to obtain an estimate of the DL long-term channel statistics (or any of its representations). To facilitate this process, a first BF CSI-RS is transmitted with a period T1 (ms) and a second NP CSI-RS is transmitted with a period T2 (ms), where T1 ≤ T2. This scheme is called hybrid CSI-RS. The implementation of hybrid CSI-RS depends heavily on the CSI processing and the definition of NZPCSI-RS resources.

[0110] In Rel.10 LTE, a codebook-based transmission scheme is used to support UL SU-MIMO transmissions. That is, the UL license (including DCI format 4) includes a single PMI field (along with the RI), which indicates that the UE should use a single precoding vector or matrix (from a predefined codebook) for scheduled UL transmissions. Therefore, when multiple PRBs are allocated to the UE, the single precoding matrix indicated by the PMI implies the utilization of wideband UL precoding. Despite its simplicity, this is clearly suboptimal because typical UL channels are frequency-selective and the UE is frequency-scheduled to use multiple PRBs for transmission.

[0111] Another drawback of Rel.10 LTE UL SU-MIMO is the lack of support for scenarios where accurate UL-CSI cannot be obtained at the gNB (which is required for proper operation of codebook-based transmissions). This situation may occur in scenarios with highly mobile UEs or in scenarios with bursty inter-cell interference in cells with poor isolation.

[0112] Therefore, new components need to be designed to achieve more effective support for UL MIMO for the following reasons: First, it is desirable to support frequency-selective (or sub-band) precoding for UL MIMO as much as possible. Second, UL MIMO should provide competitive performance even when accurate UL-CSI is not available at the gNB. Furthermore, the proposed UL MIMO solution should be able to utilize UL-DL reciprocity, where the UE uses CSI-RS to provide UL-CSI estimation for TDD scenarios.

[0113] In this disclosure, unless otherwise stated, the terms PMI (Precoding Matrix Indicator) and TPMI (Transmission PMI) are used interchangeably to indicate a UL-related DCI field, which indicates the assigned precoder or precoder group used by the UE for scheduled UL transmissions. Similarly, unless otherwise stated, the terms RI (Rank Indicator) and TRI (Transmission RI) are used interchangeably to indicate a UL-related DCI field, which indicates the assigned tier used by the UE for scheduled UL transmissions.

[0114] This disclosure includes at least four components for implementing UL MIMO. The first component includes a method for configuring precoded UL transmission. The second component includes an implementation for supporting UL frequency-selective precoding. The third component includes a method for implementing reciprocity-based UL MIMO transmission. The fourth component includes a method for UL transmission having two waveforms. Names or terms used to indicate functionality are exemplary and may be replaced with other names or labels without altering the essence of the implementation.

[0115] For the first component (i.e., configuring precoded UL transmission), an exemplary implementation for facilitating operation in various scenarios, dynamic and semi-dynamic beamforming can be described as follows. In one implementation, dynamic beamforming is particularly suitable when accurate UL-CSI is available at the gNB or UE (e.g., low UE speed and good cell isolation or inter-cell interference coordination). In this case, because accurate directional information is accessible, the UE can transmit data via a narrow directional beam. For FDD, the gNB can signal the UE to select beamforming or precoded vectors / matrices (or multiple vectors / multiple matrices) via a DL control channel (such as UL authorization). Upon receiving such precoded information, the UE should send the requested UL data to the gNB using the associated precoder or beamformer. This precoded information is dynamically updated by the gNB.

[0116] To support dynamic beamforming, codebook-based MIMO transmissions can be used, where the UL license (including the associated DCI) includes a single precoding information (PMI) field (along with the RI). This PMI indicates a single precoding matrix used by the UE for scheduled UL transmissions. Therefore, a precoder or beamforming is applied to all scheduled PRBs for that UE.

[0117] Semi-dynamic beamforming is particularly suitable when UL-CSI quality is compromised at the gNB or UE (e.g., high UE speeds and poor cell isolation leading to bursts of inter-cell interference known as the scintillation effect). In such cases, it is more advantageous for the gNB to transmit data via a set of directional beams, since the UE can only indicate approximate direction information (or range). For this purpose, a precoder (beam) that cycles within a set of beams in the time domain (on OFDM symbols) or frequency domain (on REs, RBs, or a set of RBs) can be employed. This approximate direction information can be signaled to the UE via a DL control channel (e.g., UL-permitted). This information can be a long-term precoded message or an indicator of a subset of the precoder.

[0118] For semi-dynamic beamforming, a set of multiple precoders is used in conjunction with a predetermined cyclic pattern (or set of cyclic patterns). The cyclic pattern or set of precoders can be specified and transmitted to the UE via UL authorization signaling. The PMI field for dynamic beamforming can be extended to support semi-dynamic beamforming via precoder cycling. For rank-1 (one layer) transmission, this semi-dynamic beamforming can be cascaded with transmit diversity such as SFBC or SFBC-FSTD applied to two or four beams, where the number of beams can be configured as the number of UL antenna ports.

[0119] Figure 5An exemplary operation 500 is depicted, wherein UE1 502 and UE2 503 are connected to gNB 501. The gNB schedules UL transmissions for UE1 via UL License 1 and for UE2 via UL License 2. After receiving and successfully decoding UL License 1, which contains a license for UE1 to transmit data using dynamic beamforming, UE1 transmits using dynamic beamforming in the UL. That is, UE1 precodes its data so that the data is transmitted via a narrow directional beam. The precoder used by UE1 signals via the PMI field in UL License 1. After receiving and successfully decoding UL License 2, which contains a license for UE2 to transmit data using semi-dynamic beamforming, UE1 transmits using semi-dynamic beamforming in the UL. That is, UE2 precodes its data so that the data is transmitted via multiple directional beams that cycle through the four beams in time (on OFDM symbols), frequency (on RE or RB), or both time and frequency. Figure 5 For illustrative purposes, four spatially overlapping beams are shown. The set of precoders used by UE 1, or the use of the four beams in a cyclic manner, is signaled via the PMI field in UL License 2.

[0120] In this disclosure, the terms "dynamic beamforming" and "semi-dynamic beamforming" are used for illustrative purposes. Other terms may also be used to refer to the same method and / or function. For example, terms such as "transmission scheme 1 or A" and "transmission scheme 2 or B"—or "transmission mode 1" and "transmission mode 2"—may be used to refer to two transmission methods, respectively. These two transmission schemes may also be used in conjunction with other transmission schemes.

[0121] In order to Figure 5 The dynamic or semi-dynamic beamforming shown can be used interchangeably to configure the UE, and several alternative implementations are possible.

[0122] In a first implementation, the UE is configured semi-statically with dynamic or semi-dynamic beamforming via higher-layer (e.g., RRC) signaling. An example of this implementation is performing transmission scheme or transmission mode configuration via at least one RRC parameter. In this case, the value of the RRC parameter indicates whether the UE is configured with dynamic or semi-dynamic beamforming.

[0123] In this first embodiment, the PMI field, as part of the DCI in the (previously mentioned) UL license, can be used for both dynamic and semi-dynamic beamforming. The PMI field can signal different assumptions depending on whether the UE is configured with dynamic or semi-dynamic beamforming. When the UE is configured with dynamic beamforming, the PMI field indicates the precoding matrix or vector that should be used by the UE for licensed UL data transmission. When the UE is configured with semi-dynamic beamforming, the PMI field can indicate the selection of a precoding matrix or vector group that should be used by the UE for licensed UL data transmission.

[0124] Table 1 provides an example where a time oversampling DFT vector set of length MO is used as the set of possible rank-1 precoders for M antenna ports. Therefore, (OM-1) precoder vector sets are available. As an example, the RRC or higher-level parameter indicating whether the UE is configured with dynamic or semi-dynamic beamforming is BeamformingScheme. When the parameter BeamformingScheme indicates "dynamic" (i.e., dynamic beamforming), PMI=i indicates that the UE is requested (should) use the precoder v. i For UL data transmission. When the parameter BeamformingScheme indicates "semi-dynamic" (i.e., semi-dynamic beamforming), PMI=i indicates a request for the UE to (should) use precoder group G. i (It comprises B sets of continuous precoders) for UL data transmission. Optionally, if the UL channel angle spread is large, a set of B non-continuous precoders may also be used.

[0125] Exemplary PMI table for Implementation 1

[0126] Table 1

[0127]

[0128]

[0129] G i =[v i v mod(i+1，OM) ... v mod(i+B-2，OM) v mod(i+B-1，OM) (Equation 1)

[0130] In the second embodiment, the UE is dynamically configured with dynamic or semi-dynamic beamforming via a UL license transmitted on the DL control channel.

[0131] An example of this second implementation utilizes a DCI parameter to instruct the UE to select a transmission scheme or mode (dynamic or semi-dynamic) that should be used by the UE for licensed UL data transmission. In this example, the PMI field, which is part of the DCI in the UL license, can be used for both dynamic and semi-dynamic beamforming. The PMI field is also required depending on the value of the DCI parameter (i.e., whether the UE is configured with dynamic or semi-dynamic beamforming). When the UE is configured with dynamic beamforming, the PMI field indicates the precoding matrix or vector that should be used by the UE for licensed UL data transmission. When the UE is configured with semi-dynamic beamforming, the PMI field can indicate the selection of a precoding matrix or vector group that should be used by the UE for licensed UL data transmission. This example can be described similarly to Table 1. However, in this case, the higher-level parameter BeamformingScheme can be replaced by the DCI field BeamformingScheme, which takes a value of 0 (indicating, for example, semi-dynamic beamforming) or a value of 1 (indicating, for example, dynamic beamforming).

[0132] Another example of this second implementation is to utilize only one PMI field as part of the DCI in the UL license. In this case, considering the total N associated with the B-bit PMI field... H There are N possible hypotheses (where N is N) H ≤2 B ), N H Some of the assumptions N H，d This can be used to indicate the selection of pre-encoders for dynamic beamforming, while the rest (N) H，sd =N H -N H，d (A set of hypotheses) can be used to indicate the selected precoder group for semi-dynamic beamforming. An example can be described in Table 2. Compared to Table 1, Table 2 combines hypotheses from dynamic and semi-dynamic beamforming into a set indicated by the PMI field. For this example, the number of hypotheses associated with the PMI field is twice the number associated with the PMI field in the first example of the second embodiment and in the first embodiment.

[0133] Exemplary PMI table for Implementation Method 2 (Second Example)

[0134] Table 2

[0135]

[0136] G i =[v i v mod(i+1，OM) ... v mod(i+B-2，OM) v mod(i+B-1，OM) (Equation 2)

[0137] Optionally, a two-dimensional precoder or codebook can be utilized (especially those related to two-dimensional or rectangular array geometry). In this case, the precoder may correspond to a pair of indices (m1, m2), where each index represents one of the two dimensions. The simulation of the exemplary rank-1 precoder described above can be found in Equation 3 (where v... i and G i This is described in Equation 2. Here, M1 and M2 represent the number of ports in the first and second dimensions, respectively. Similarly, O1 and O2 represent the oversampling factors in the first and second dimensions, respectively.

[0138]

[0139]

[0140]

[0141] Alternatively, a one-dimensional precoder or codebook designed for a dual-polarization array configuration can also be used. In this case, a precoder with two identical parts (each part associated with a polarization group) and cophase between the two polarization groups can be used. The simulation of the exemplary one-dimensional 2M-port (comprising each of the two polarization groups with M ports) rank-1 precoder described above can be described in Equation 4. Here, K possible cophase values ​​are used.

[0142]

[0143]

[0144] G m =[v m v mod(m+1，OM) … v mod(m+B-2，OM) v mod(m+B-1，OM) (Equation 4)

[0145] m=(K-1)i+k

[0146] Alternatively, a two-dimensional precoder or codebook designed for a dual-polarization array configuration can also be used. The simulation of the exemplary two-dimensional 2M1M2 port (including each of the two polarization groups of the M1M2 port) rank-1 precoder described above can be described in Equation 5. Beamgroups can be defined similarly to the three indices m1, m2, mk that constitute a single PMI.

[0147]

[0148]

[0149]

[0150] With any of the codebook options mentioned above, a DL signaling implementation that supports switching between dynamic beamforming and semi-dynamic beamforming is applicable and can be extended in a direct forward manner (since each precoder or codebook corresponds to a single PMI).

[0151] For the second component (i.e., supporting UL frequency-selective precoding), in the above-described embodiment related to the first component, a single precoder is instructed to the UE for UL transmission. Therefore, for a single allocation, the same precoder is applied to all allocated RBs. Optionally, subband precoding can also be supported by signaling a PMI per subband via UL authorization, where one subband may include multiple consecutive RBs. In this case, the DCI field containing precoding information includes multiple PMIs, each of which is associated with a subband and indicates the selection of a precoder from a predetermined codebook.

[0152] Figure 6 Exemplary DL signaling for subband precoding and UE processing is shown to explain the inclusion of N PMI The DCI field represents the pre-coding information of each PMI (each associated with a subband). The number of PMIs is N. PMI Subband size P of RB SUBBAND (P 子带 Interdependent. For a given UL resource allocation span (in terms of the number of RBs RA) RB (This is represented as follows), the PMI can be obtained as follows: Therefore, for a given UE resource allocation, the number of PMIs does not directly depend on the number of RBs allocated to the UE, because UL resource allocations can include multiple consecutive RBs (as shown in 601) or clustered RBs (as shown in 602). Instead, it depends on the number of RBs within the associated UE resource allocation, starting from the lowest-indexed RB and proceeding to the highest-indexed RB. Let the lowest-indexed RB and the highest-indexed RB be denoted as RB. low (RB 低 ) and RB high (RB 高 ), Selectively, in RA RB，i In the case of the number of RBs in the i-th cluster, it is also possible to use Figure 6 The two examples given illustrate contiguous resource allocation (601) and clustered resource allocation (602). Here, for illustrative purposes, P is used. SUBBAND =4. Although the total number of RBs allocated in 602 is less than the total number in 601, the total number of sub-bands, and therefore the number of PMIs, is greater. They are the same because the DL allocation span is the same for 601 and 602.

[0153] like Figure 7 As shown, several DL signaling implementations exist for supporting subband precoding. The examples below differ in several aspects, such as whether the associated DCI payload size is fixed or varies with the number of subbands corresponding to the allocated RB (and therefore, the number of subband PMIs), whether all PMI components are included in the DCI or at least some PMI components are signaled outside the DCI (or main DCI), and / or whether the number of subbands corresponding to the allocated RB (and therefore, the number of subband PMIs) is fixed or varies according to UL resource allocation. When the number of subband PMIs is fixed, the PMI granularity (subband size) varies according to UL resource allocation. Conversely, when the PMI granularity (subband size) is fixed, the number of subband PMIs varies according to UL resource allocation.

[0154] In the first embodiment 1, as shown by DCI 710, N is used PMI The DCI fields 711 and 712 are precoding information with variable lengths for each PMI (each associated with a subband). In this case, the subband size (the number of RBs per subband) is fixed. The number of PMIs N PMI The size of the DCI associated with the UL license is variable, depending on the allocation size and the location of the allocated RBs (e.g., whether the allocated PRBs are contiguous or clustered). This increases the number of blind decoding attempts at the UE. Figure 7 As shown in DCI 710, the lengths of the precoded information DCI fields 711 and 712 are scaled according to the number of PMIs inferred from the resource allocation information, where DCI field 712 indicates that more PMIs need resource allocation than DCI field 711 (such as the case where more RBs are allocated to DCI field 712 than to DCI field 711).

[0155] In the second embodiment 2, as shown by DCI 720, precoding information (N) containing at least the information required to support subband precoding is used. PMIThe second (or second-level) DL control information (for each PMI). In this case, the subband size (the number of RBs per subband) is fixed. The location and size of this precoding information can be determined based on the resource allocation indicated in the associated UL license. In this case, the UE first receives the UL license and decodes the DCI field indicating the resource allocation. After decoding the resource allocation information, the UE decodes the second DL control information containing only precoding information. This precoding information indicates the precoder used by the UE for each RB (subband) set, and therefore for each RB allocated to the UE. Including N PMI The length of the pre-coding information DCI field for each PMI is variable and can be inferred from the resource allocation information from the first DL control information. Therefore, it does not increase the number of blind decoding attempts associated with the first DL control information.

[0156] In this embodiment, the first DL control information may be transmitted via the L1 DL control channel (simulated as LTE PDCCH or ePDCCH) using either C-RNTI or UE ID. The second DL control information may be transmitted separately from the first DL control information, wherein transmission parameters such as its location (in the time and / or frequency domain) and / or payload size and / or MCS can be inferred implicitly (e.g., from C-RNTI and / or some other UE-specific parameters) or explicitly (indicated as the DCI field in the first DL control information) from the first DL control information. C-RNTI or UE ID may or may not be used for the second DL control information. Figure 7 As shown in DCI 720, the length of the precoding information DCI field is scaled according to the number of subband PMIs inferred from the resource allocation information, where DCI field 722 indicates that more PMIs require resource allocation than DCI field 721 (e.g., allocating more RBs to DCI field 722 than to DCI field 721). However, unlike the first embodiment, as shown in DCI 710, the length of the first DL control information containing resource allocation information remains the same, while the length of the second DL control information varies according to the required number of subband PMIs.

[0157] The second DL control information may be transmitted via an L1 DL control channel (e.g., simulating LTE PDCCH or ePDCCH – thus perceived as a second-level DCI) or as part of a resource / channel for DL ​​data transmission (e.g., simulating LTE PDSCH). It may reside in the same time slot / subframe as the DCI (or first-level DCI, thus UL permitted) or in a different time slot / subframe. Regardless of whether the second DL control information is transmitted via a second-level DCI or DL ​​data channel transmission (simulating LTE PDSCH), a CRC may be appended to its information bits for error detection at the UE.

[0158] In the third embodiment 3, as shown by DCI 730, a fixed number N including PMI is used. PMI A fixed-length precoding information DCI field 731 of >1 (each associated with a subband). Therefore, only a single N is allowed. PMI Value. In this case, the subband size (the number of RBs in each subband) can be variable, depending on the resource allocation (allocation size and the location of the allocated RBs).

[0159] For example, in N PMI In the case of 2, only two PMIs (and therefore two separate precoders) can be allocated to the UE. The first PMI indicates the precoder associated with a first subset of the allocated RBs, and the second PMI indicates the precoder associated with a second subset of the allocated RBs, where the second subset is different from the first subset—where the first and second subsets together constitute all the RBs allocated to the UE. Therefore, the number of allocated RBs in each of the two subsets is variable (depending on resource allocation). Thus, the size of the DCI associated with the UL license is fixed, and the number of RBs associated with each of the two PMIs is variable. In this case, the number of blind decoding attempts associated with the first DL control information is not increased. Figure 7 As shown in DCI 730, the length of the precoded information DCI field remains the same because a fixed number of PMIs are used for any resource allocation (i.e., the number of RBs allocated and / or the location of the allocated RBs).

[0160] For the third implementation, several sub-implementations relating to the interpretation of each PMI and the associated sub-band size can be described as follows.

[0161] In the first sub-implementation, with N PMI The set / subset of each associated RB in each subband varies with resource allocation (i.e., the number of RBs allocated and / or the location of the allocated RBs). However, for a given / fixed resource allocation, with N PMIThe set / subset of each associated RB in a subband is fixed, predetermined, or configured via higher-level signaling. This can be, for example, in... Figure 6 As shown in the diagram. That is, for a given number and / or location of RBs indicated in the UL Resource Allocation (RA) field, each subband constitutes the same number of PRBs and / or a subset of PRBs. Therefore, no additional indication is required in the associated UL-related DCI or via any other DL signaling mechanism.

[0162] In the second sub-implementation, the relationship with the i-th PMI (PMI) can be changed. i Where i = 0, 1, ..., N PMI -1) Associated subbands, and therefore dynamically signaled via UL-related DCI. In this case, only signaling (N) is required. PMI -1) subbands of PMI, because a subband for a remaining PMI can be obtained from the RA field and (N PMI -1) The remaining subbands in the subbands are derived. Therefore, except for N PMI In addition to the PMI / TPMI, (N) PMI -1) Additional fields (each indication in the additional fields is related to (N) PMI -1) Subbands associated with PMI) via UL-related DCI signaling. For example, in N PMI In the case of 2, an additional sub-band indicator field (for either the first or second PMI) is transmitted via UL-related DCI signaling. In a variant of this sub-implementation, one of the two PMIs (denoted as PMI) SB,1 This can indicate the precoder used only for the RB indicated in the Additional Subband Indicator field (e.g., interpreted as simulating a "best-M" subband, where the value of M can be configured as part of the Additional Subband Indicator field either dynamically via MAC CE or semi-statically via higher-layer signaling), and another PMI (denoted as PMI). SB,2 This can indicate the broadband precoder that is available for all allocated RBs (indicated in the Resource Allocation DCI field). In another variation of this sub-implementation, one of the two PMIs (denoted as PMI) SB,1 This can indicate the precoder used only for the RB indicated in the Additional Subband Indicator field (e.g., interpreted as analogous to "Best-M" subband, where the value of M can be configured either as part of the Additional Subband Indicator field or dynamically via MAC CE signaling, or semi-statically via higher-layer signaling), while another PMI (denoted as PMI) SB,2 This can indicate the precoder of the RB used for the remaining allocation (indicated in the Resource Allocation DCI field).

[0163] To avoid any changes in the DCI size that could increase the number of blind decoded UEs for DL ​​control signaling, the size of the additional subband indicator field can be fixed or configured via higher-layer signaling. Therefore, the number of assumptions (or, in addition, the set of assumptions) associated with the subband indicator field can be fixed or configured via higher-layer signaling. For example, to allocate resources for PMI... SB,2 The number of subband hypotheses remains at the maximum N. HYP When N RB When an RB is allocated to a UE (as indicated in the Resource Allocation DCI field), the possible number of subbands (N) RB A subset of RBs can be configured for a fixed or higher level of no more than N. HYP If each of these possible subbands has the same size in terms of the number of RBs and the RBs within each subset are as contiguous as possible, then each of the possible subbands can roughly include RB.

[0164] In the fourth implementation method 4, the precoded information DCI field may contain the number N of PMIs. PMI The maximum possible value of K is [value missing]. This implementation can be considered as an intermediate zone between implementation 1 and implementation 3. In this case, the sub-band size (the number of RBs in each sub-band) can be variable, depending on the resource allocation (the size and location of the allocated RBs). For example, when K = 2 and N [value missing], [value missing]. PMI In the case of ∈{1,2}, the precoding information DCI field may contain one or two PMIs. When the precoding information DCI field contains one PMI, the UE should use the precoder indicated by the PMI for all its allocated RBs. When the precoding information DCI field contains two PMIs, the first PMI indicates the precoder associated with a first subset of the allocated RBs and the second PMI indicates the precoder associated with a second subset of the allocated RBs, wherein the second subset is different from the first subset—wherein the first and second subsets are combined to constitute all RBs allocated to the UE. Therefore, the number of allocated RBs for each of the two subsets is variable (depending on resource allocation).

[0165] Therefore, the size of the DCI associated with the UL license is variable (it can be one of two possible sizes), and the number of RBs associated with the PMI is variable. This increases the number of blind decoding attempts at the UE, but only by a factor of 2. This is in addition to the fact that there are only two possible lengths of precoded information (with N... PMI (associating the two values), Implementation 4 can be achieved by... Figure 7 The DCI 710 is shown in a similar manner.

[0166] For any of the above exemplary embodiments for supporting subband precoding, particularly for embodiment 2 in which second DL control information including subband PMI is used ( Figure 7 In DCI 720, an additional assumption may exist in the DCI (or Level 1 DCI) that indicates the UE may assume precoding information (including PMI, wideband component, or subband component) from previous (or most recent) signaling for use in licensed UL transmissions. This assumption may also indicate that the same precoder (wideband and / or subband) used in the signaling in previous (or most recent) licensed UL transmissions may be used.

[0167] Several options are possible for this additional assumption used for signaling. First, the assumption can be associated with a code point of any other existing UL-related DCI field. This is relevant, for example, when precoded information is not included in the DCI (or Level 1 DCI). Some exemplary DCI fields include resource allocation, DCI fields indicating transmission schemes, or UL DMRS information. Second, a dedicated 1-bit DCI field indicating the presence of a second DL control information containing precoded information (such as subband PMI). Furthermore, when using a two-level codebook (described later in this disclosure), the wideband (Level 1) PMI component can be included in the DCI (or Level 1 DCI) and the signaling is a first PMI DCI field. In this case, the additional assumption can be included as a code point of the first PMI DCI field.

[0168] Therefore, when this additional assumption is detected at the UE, the UE does not attempt to decode the second DL control information, which includes the subband PMI, and assumes the previous (most recent) signaling and received precoded information. This scheme helps save DL control overhead because, for example, when the gNB / network does not appear to require changes to the UL precoder, the second DL control information (which may include the subband PMI) is not signaled.

[0169] Variation of Implementation 2 using the above additional assumptions ( Figure 7 DCI 720) can be used Figure 8As shown in 800. In this illustrative example, additional assumption 805 is signaled as one of the two-valued information (DL control information 1) included in DCI 801. Other options can be used as previously disclosed. When this additional assumption is signaled (in DCI field 803), the second DL control information (represented as precoded information including the subband PMI) is not signaled. Therefore, upon detecting assumption 805, the UE can assume the precoder (PMI) signaled in the most recently decoded / received precoded information (e.g., from the most recently decoded / received UL license). Otherwise, the new / updated precoded information is signaled. In this case, the UE should receive / decode the second DL control information including the precoded information based on the decoded UL resource allocation in DCI 802 or 803.

[0170] Any of the above embodiments for supporting subband precoding is applicable to dynamic beamforming and can therefore be combined with mechanisms for semi-dynamic beamforming (such as those illustrated in Tables 1 and 2). That is, for the purpose of precoder / beamformer cycling, dynamic beamforming can be associated with DL control signaling mechanisms for subband precoding, while semi-dynamic beamforming is associated with DL control mechanisms for indicative precoder groups.

[0171] Additionally, when dynamic and semi-dynamic beamforming can be dynamically configured for the UE, the UE can also be configured via higher-layer (RRC) signaling through a single precoder used for all allocated RBs (“wideband” precoding) or subband precoding. In this case, the RRC parameter is used to configure the UE through “wideband” precoding (a single precoder used for all allocated RBs) or subband precoding (potentially multiple precoders, each used for a subset of allocated RBs). For example, the binary RRC parameter SubbandPrecodingEnabled can be used. When its value is “TRUE” or “ON”, the UE is configured using subband precoding. In this case, multiple PMIs (including one PMI, depending on the implementation) can be used, depending on one of the four aforementioned implementations for subband precoding. When its value is “FALSE” or “OFF”, the UE is configured using “wideband” precoding. In this case, a single PMI is used regardless of UE resource allocation.

[0172] The above exemplary embodiments regarding signaling support for facilitating switching between dynamic and semi-dynamic beamforming, as well as embodiments for supporting subband precoding, are applicable not only to single-level precoder structures (and therefore, to single-level codebooks) but also to two-level precoder structures (and therefore, to two-level codebooks).

[0173] For the third component (i.e., an implementation with a two-level codebook based on a two-level precoder), the precoding vector or matrix is ​​associated with two indices (e.g., i1 and i2), where the first index indicates a wideband component and the second index indicates a possible subband component. An example of such a precoder structure is... (Similar to the Rel.12 LTE DL MIMO codebook), where, For broadband (i.e., single-stage precoder) Therefore, it is also i1, used for all allocated RB), and It can be wideband or subband (i.e., single-stage - two pre-encoders) Therefore, it is also i2, which can be used for different allocated RBs, depending on whether "wideband" precoding or subband precoding is configured for the UE. This pair of indices (i1, i2) corresponds to the precoder (vector or matrix) in the configured precoding codebook. First precoder (Together with its associated PMI value i1) can correspond to a pre-encoder group, wherein the second pre-encoder (Together with its associated PMI value i2) can correspond to The selection and linear combination of precoder groups. In the case of a dual-polarized antenna, the second precoder... (Together with its associated PMI value i2) it may also include co-phase operations between two polarization groups.

[0174] Furthermore, a two-dimensional two-level precoder or codebook can be utilized (especially those geometrically related to two-dimensional or rectangular arrays). In this case, the first PMI value i1 can be derived from two indices (i 1，1 i 1，2 The precoder structure is composed of two elements, each corresponding to one of the two dimensions. Therefore, the corresponding precoder structure can be written as... (Similar to the Rel.13 LTE DL MIMO codebook). Here, For broadband (i.e., single-stage precoder) Therefore, it is also (i 1，1 i 1，2 ), for all allocated RB) and It can be wideband or subband (i.e., single-stage - two pre-encoders) Therefore, it is also i2, which can be used for different allocated RBs, depending on whether "wideband" precoding or subband precoding is configured for the UE. This index group (i 1，1 i 1，2 , i2) corresponds to the precoder (vector or matrix) in the configured precoder codebook. First precoder (together with its associated PMI value (i 1，1 i 1，2)) can correspond to a pre-encoder group, wherein the second pre-encoder (Together with its associated PMI value i2) can correspond to The selection and linear combination of precoder groups. In the case of a dual-polarized antenna, the second precoder... (Together with its associated PMI value i2) it may also include co-phase operations between two polarization groups.

[0175] The following implementation for a two-stage precoder or codebook is applicable to one-dimensional or two-dimensional precoders. For a two-dimensional precoder or codebook structure, the first PMI value i1 can be derived from two indices (i 1，1 i 1，2 Therefore, the first-level precoder can be associated with these two indices:

[0176] For example, to configure the UE interchangeably with dynamic or semi-dynamic beamforming for a two-stage precoder, several alternative implementations simulating the above-described embodiments and examples for a single-stage precoder are possible. For a two-stage precoder or codebook, this pair of PMI values ​​(i1, i2) (or for a two-dimensional precoder, (i...)...) 1，1 i 1，2 i2) can provide natural support for dynamic and semi-dynamic beamforming. When dynamic beamforming is configured, the PMI signaling given to the UE includes i1 (which is composed of (i) for the QR codebook. 1，1 i 1，2 The signaling to the UE for the PMI consists of both i1 and i2. When semi-dynamic beamforming is configured, the signaling to the UE for the PMI only includes i1 (which is composed of i1 for the two-dimensional precoder). 1，1 i 1，2 (i2) constitutes the value of the second pre-encoder. (Together with its associated PMI value i2) indicates the precoder group that the UE should perform a loop on for its UL data transmission.

[0177] In a first implementation, the UE is configured semi-statically with dynamic or semi-dynamic beamforming via higher-layer (e.g., RRC) signaling. An example of this implementation is performing transmission scheme or transmission mode configuration via at least one RRC parameter. In this case, the value of the RRC parameter indicates whether the UE is configured with dynamic or semi-dynamic beamforming.

[0178] In this first embodiment, the PMI field (mentioned above), which is part of the DCI in the UL license, can be used for both dynamic and semi-dynamic beamforming. Depending on whether the UE is configured with dynamic or semi-dynamic beamforming (i.e., according to the setting of higher-level parameters indicating whether the UE is configured with dynamic or semi-dynamic beamforming, or more generally, the first or second transmission scheme), the PMI field can assume different assumptions. When the UE is configured with dynamic beamforming, the PMI field indicates the precoded matrix or vector that should be used by the UE for licensed UL data transmission. In this case, the PMI field i includes two indices (which are composed of (i...) for the QR code book...) 1，1 i 1，2 The PMI field i1 consists of the codebook and its i2. When the UE is configured with semi-dynamic beamforming, the PMI field i can indicate the selection of a precoding matrix or vector group that the UE should use for permitted UL data transmission. In this case, the PMI field i only includes the i1 of the same codebook.

[0179] For example, the RRC or higher-level parameter BeamformingScheme is used to indicate whether the UE is configured with dynamic beamforming or semi-dynamic beamforming. When the parameter BeamformingScheme indicates "dynamic" (i.e., dynamic beamforming), PMI = (i1, i2) indicates that the UE is requested (should) use the precoder. For use in UL data transmission. The PMI can be jointly encoded as a single PMI parameter i, or it can be indicated as two separate parameters. When the parameter BeamformingScheme indicates "semi-dynamic" (i.e., semi-dynamic beamforming), PMI = i1 indicates a request for the UE to (should) use i1 (e.g., ...). The associated pre-encoder group is used for UL data transmission. For the QR code book, i1 is composed of (i 1，1 i 1，2 )constitute.

[0180] Additionally, when dynamic and semi-dynamic beamforming can be configured semi-statically for the UE via higher-layer signaling, the UE can also be configured via higher-layer (RRC) signaling through a single precoder for all allocated RBs (“wideband” precoding) or subband precoding. In this case, the RRC parameter is used to configure the UE through “wideband” precoding (a single precoder for all allocated RBs) or subband precoding (potentially multiple precoders, each for a subset of allocated RBs). For example, the binary RRC parameter SubbandPrecodingEnabled can be used. When its value is “TRUE” or “ON”, the UE is configured using subband precoding. In this case, multiple PMIs (including one PMI, depending on the implementation) can be used according to one of the four aforementioned embodiments for subband precoding. When its value is “FALSE” or “OFF”, the UE is configured using “wideband” precoding. In this case, a single PMI is used regardless of UE resource allocation.

[0181] In the second embodiment, the UE is configured dynamically via dynamic or semi-dynamic beamforming, either via a MAC control element (MAC CE) or via a UL license transmitted on the DL control channel.

[0182] An example of this second implementation utilizes a DCI parameter to instruct the UE to select a transmission scheme or mode (dynamic or semi-dynamic) (or more generally, a first or second transmission scheme) to be used by the UE for licensed UL data transmission. In this example, the PMI field, which is part of the DCI in the UL license, can be used for both dynamic and semi-dynamic beamforming. The PMI field is also required depending on the value of the DCI parameter (i.e., whether the UE is configured with dynamic or semi-dynamic beamforming, or more generally, the first or second transmission scheme). When the UE is configured with dynamic beamforming, the PMI field indicates the precoding matrix or vector to be used by the UE for licensed UL data transmission. When the UE is configured with semi-dynamic beamforming, the PMI field may indicate the selection of a precoding matrix or vector group to be used by the UE for licensed UL data transmission. The DCI field BeamformingScheme takes a value of 0 (indicating, for example, semi-dynamic beamforming) or a value of 1 (indicating, for example, dynamic beamforming).

[0183] Another example of this second implementation is to utilize only one PMI field as part of the DCI in the UL license. In this case, considering the B-bit PMI field (where N... H ≤2 B The total N associated H One possible hypothesis, N HSome of the assumptions N H，d This can be used to indicate the selection of pre-encoders for dynamic beamforming, while the rest (N) H，sd =N H -N H，d (One hypothesis) can be used to indicate the selected precoder set for semi-dynamic beamforming.

[0184] To facilitate sub-band precoding used in two-stage precoding, the simulation is adapted for use in a single-stage precoder. Figure 6 , Figure 7 and Figure 8 Several alternative implementations of the above-described embodiments and examples can be extended to adapt to a pair of PMI values ​​(i1, i2), where i1 (which can be derived from (i...) for a QR code book... 1，1 i 1，2 i1 is the broadband and i2 is the subband. In this case, i1 (which is composed of (i) used for the QR code book) 1，1 i 1，2 The number of bits associated with the (i) structure remains the same, regardless of the number of PMIs or UE resource allocation. That is, only one DCI field requires signaling i1 (which can be generated by (i) used for the QR code book). 1，1 i 1，2 The number of bits associated with i2 is independent of the number of PMIs or UE resource allocation. Only the number of bits associated with i2 can be scaled or changed based on the number of PMIs or UE resource allocation. Therefore, the precoded information includes only one i1 (which consists of (i...) used for the QR codebook). 1，1 i 1，2 The parameters consist of multiple possible i2 values ​​(each i2 value corresponds to an RB group). Specifically, for implementation 2, which uses second-level DL control information including sub-band PMI... Figure 7 (720), i1 can be included in the DCI (or the first-level DCI), because i1 (which can be generated by the (i) used for the QR code book) 1，1 i 1，2 The structure is broadband. Since i2 is a sub-band, the sub-band PMI included in the second-level DL control information includes i2 for all sub-bands corresponding to the allocated UL resources.

[0185] Any of the implementations used to support subband precoding is suitable for dynamic beamforming and can therefore be combined with mechanisms for semi-dynamic beamforming. That is, for the purpose of precoder / beamformer cycling, dynamic beamforming can be associated with a DL control signaling mechanism for subband precoding, while semi-dynamic beamforming is associated with a DL control mechanism for indicating precoder groups or sets.

[0186] Additionally, when dynamic and semi-dynamic beamforming can be dynamically configured for the UE, the UE can also be configured via higher-layer (RRC) signaling through a single precoder for all allocated RBs (“wideband” precoding) or subband precoding. In this case, the RRC parameter is used to configure the UE through “wideband” precoding (a single precoder for all allocated RBs) or subband precoding (potentially multiple precoders, each for a subset of allocated RBs). For example, the binary RRC parameter SubbandPrecodingEnabled can be used. When its value is “TRUE” or “ON”, the UE is configured using subband precoding. In this case, multiple PMIs (including one PMI, depending on the implementation) can be used according to one of the four aforementioned embodiments for subband precoding. When its value is “FALSE” or “OFF”, the UE is configured using “wideband” precoding. In this case, a single PMI is used regardless of UE resource allocation.

[0187] For the fourth component (i.e., supporting reciprocity-based UL transmission), when UL-DL channel reciprocity is feasible, such as in TDD scenarios, the UE can obtain an estimate of the UL channel from the DL CSI-RS measurement. In this case, the UE can calculate its own precoder for a given resource allocation. This eliminates the need for the DCI field of the precoder information via DL control channel signaling.

[0188] Therefore, in one implementation (4.1), the UL-licensed DCI only includes the number of transport layers without any PMI (i.e., transport rank). However, it should be noted that although the UE can obtain an estimate of the UL channel to derive its precoder, this precoder calculation may be inaccurate due to the lack of UL interference information (primarily intra-cell interference, which can only be obtained at the gNB via SRS measurements). This is particularly relevant in UL multi-user MIMO (MU-MIMO). To address this problem, several implementations are proposed in this disclosure—one or a combination of these implementations may be utilized.

[0189] In another implementation (4.2), the same or similar precoding information as described in component 2 or 3 may be used. That is, the DCI for UL licensing includes precoding information including one or more PMIs, depending on whether “wideband” or subband precoding and / or UE resource allocation is configured. All implementations for the DCI field of precoding information given in component 2 or 3 are applied.

[0190] In another implementation (4.3), the precoding information DCI field, which is a single field, is included via DL control channel signaling. This single field may indicate a precoder group or set. The precoder group may be obtained from a predefined codebook and is defined as a subset of all precoders in the codebook. This precoder subset selection may be performed for each rank value indicated to the UE via the transmission RI or TRI. In this case, for a given RI (or TRI) value, the PMI (or TPMI) indicates a precoder subset or group specific to the RI (or TRI) value. Optionally, this precoder subset selection may be performed on a codebook associated with all possible values ​​of RI (or TRI). In this case, a single precoder subset or group may be defined, which may include precoders from one codebook (associated with one value of RI / TRI) or multiple codebooks (associated with multiple values ​​of RI / TRI). Therefore, the PMI / TPMI can be interpreted without any reference or with only a partial reference to RI / TRI.

[0191] The precoder set or group may include precoders that the UE should select or combine. That is, since the UE can obtain an estimate of the UL channel via CSI-RS by utilizing DL-UL channel reciprocity, this UL channel estimate can be used to select or obtain precoders from a combination of precoder subsets or groups indicated via PMI. This restriction on the precoder subset can be used by the gNB to configure the UE to select a precoder considering knowledge of intra-cell UL interference caused by gNB scheduling. For example, such precoder selection can minimize intra-cell interference caused by the UE to other UEs or by other UEs to this UE. Alternatively, the single field can indicate a precoder set that the UE should avoid. This avoidance of the precoder subset can be used by the gNB to configure the UE to avoid selecting a precoder considering knowledge of intra-cell UL interference caused by gNB scheduling. For example, such precoder selection can exacerbate intra-cell interference caused by the UE to other UEs or by other UEs to this UE.

[0192] In this embodiment, the same signaling mechanism as that used for semi-dynamic beamforming can be used. For example, if a single-level precoder or codebook is used, a precoding group DCI signaling mechanism similar to that in Table 1 or Table 2 for semi-dynamic beamforming can be utilized, as shown in Table 3. Here, G p This represents the p-th group of B precoders.

[0193] Example precoding information table for TDD scenarios: Level 1 precoder

[0194] Table 3

[0195]

[0196]

[0197] If a two-level precoder or codebook is used, the PMI field in the precoding information field of the signaling to the UE only includes the first PMI i1, which also represents the precoder group (which can be generated by (i) used for the two-level precoder). 1，1 i 1，2 (Construction). This precoding group signaling is "wideband", meaning that only one field is signaled for any UE resource allocation.

[0198] Any of the three implementations described above can be used in TDD scenarios where DL-UL channel reciprocity is feasible. Optionally, at least two of these three implementations can be supported and configured for the UE via higher-layer (RRC) signaling.

[0199] When DL CSI-RS is used for UL CSI acquisition (particularly for precoder calculation), the UE can be configured via at least one CSI-RS resource for this purpose. This CSI-RS resource configuration may be the same as or different from the resource configuration used for DL ​​CSI acquisition. Typical CSI-RS resource parameters may include in this resource configuration, such as the number of CSI-RS ports, temporal behavior (periodic, semi-persistent, or aperiodic), subframe configuration (which includes subframe frequency shift and periodicity – applicable to periodic and semi-persistent CSI-RS), EPRE (energy per RE) or power level, CSI-RS mode (within a time slot / subframe, which also includes frequency density), and when more than one CSI-RS resource can be configured, and the number of NZP CSI-RS resources (K≥1).

[0200] If the same CSI-RS resource configuration is used for UL CSI acquisition as for DL ​​CSI acquisition, higher-level (RRC) parameters can be used to indicate whether the CSI-RS resource configuration corresponds to DL or UL measurements (e.g., CSI, channel, or interference measurements – note that UL and DL interference profiles are typically non-reciprocal). Optionally, this indication can be included in the resource settings or measurement settings for UL CSI acquisition. Optionally, indications from UL measurements distinguishing the use of a CSI-RS between DL measurements can be avoided by configuring the UE with K ≥ 1 CSI-RS resources and dynamically signaling the CSI-RS resource index to the UE via MAC CE or UL-related DCI. This CSI-RS resource index indicates which N (e.g., N = 1) of the K configured CSI-RS resources is allocated to the UE for UL CSI measurement / acquisition. In this case, each of the K CSI-RS resources can be assigned its own parameters (such as the number of ports, subframe configuration where applicable, mode, etc.).

[0201] When a UE is configured via CSI-RS resources for UL CSI measurements, constraints can also be imposed on CSI or precoder calculations. For example, the number of UE antenna ports used for CSI calculations using DL CSI-RS can be set to the number of SRS antenna ports used for the corresponding SRS resource settings. Another possible constraint that the UE can assume is the bandwidth of the CSI-RS transmission. When configuring CSI-RS resources for UL measurements, its transmission bandwidth can be set to the UL transmission bandwidth, the RB associated with the UL resource allocation included in the UL-related DCI (especially associated with aperiodic CSI-RS), or a pre-configured value (via higher-level / RRC, MAC CE, or L1 DL control signaling such as DCI).

[0202] To facilitate the use of DL-UL channel reciprocity for UL transmission, several alternative implementation methods can be used.

[0203] In one implementation, in addition to "Subband PMI" (one PMI for each subband within the allocated resource / RB) and "Wideband PMI" (one PMI for all subbands within the allocated resource / RB), an additional "No PMI" configuration and / or "Set / Group of Precoders" configuration may be added. This PMI configuration can be used in conjunction with the transport scheme configuration.

[0204] In another implementation, a separate UL transmission scheme can be defined in addition to existing transmission schemes. For example, a reciprocity-based transmission scheme (or transmission scheme 3) can be defined in addition to "dynamic beamforming" (or transmission scheme 1) and "semi-dynamic beamforming" (or transmission scheme 2, such as a diversity-based transmission scheme). For example, when the UE is configured with a reciprocity-based transmission scheme (or transmission scheme 3), the UE can interpret the precoding information (PMI) in the UL-related DCI as an indicator of a set / group of precoders for the UE. Based on DL channel measurements from CSI-RS, the UE can obtain an estimate of the UL channel via DL-UL channel reciprocity. This UL channel estimate can then be used to select or obtain precoders from or from combinations of precoder subsets or groups indicated via the PMI. Through this process, the UE can compute a single precoder for all allocated RBs, or compute a precoder for each of the allocated RBs. This precoder computation can be specified to or left to the UE implementation.

[0205] In another implementation, a separate configuration can be defined as indicating that the UE is configured using either "reciprocity-based" or "non-reciprocity-based" UL transport or precoder calculation or PMI mode (or simply PMI interpretation). This configuration can be signaled via higher-layer (RRC) or L1 / L2 control signaling (DCI or MAC CE). Similarly, when the UE is configured using "non-reciprocity-based" operation, the UE can interpret the precoding information (PMI) in the UL-related DCI as an indicator of a set / group of precoders for the UE. Based on DL channel measurements from CSI-RS, the UE can obtain an estimate of the UL channel via DL-UL channel reciprocity. This UL channel estimate can then be used to select or obtain precoders from or from a combination of precoder subsets or groups indicated via the PMI. Similarly, through this process, the UE can calculate a single precoder for all allocated RBs, or calculate a precoder for each of the allocated RBs. This precoder calculation can be specified to or left to the UE implementation.

[0206] Implementation 4.3 of the fourth component is described assuming the use of a single PMI / TPMI indicating the allocated precoder subset / group. Therefore, if the UE applies frequency-selective precoding to the corresponding UL transmission, the UE assumes the same precoder subset / group for all allocated RBs. However, for high-frequency scenarios where allocated RBs can span a wide frequency range, a single precoder group for all allocated RBs may be insufficient. Therefore, in a variant of this implementation, multiple PMIs / TPMIs may be included in the UL-related DCI, where each PMI / TPMI indicates the allocation of a precoder group / subgroup for a specific subband. That is, the precoder group / subset allocation is frequency-selective. For this variant, any implementation of the second component regarding the signaling subband PMI / TPMI in the UL-related DCI is applied. In this case, the subband size or configuration used for precoder group / subset allocation may be the same as or different from the subband size or configuration used for precoder allocation.

[0207] For the fifth component (i.e., supporting dual-waveform UL transmission), the UL transmission can support OFDM (CP-OFDM, i.e., OFDM with a cyclic prefix) and DFT-S-OFDM (DFT extended OFDM), where DFT-S-OFDM is used for single-stream transmission. In this case, several possible implementations can be described as follows.

[0208] In one implementation (5.1), when the UE is configured with UL SU-MIMO, the UE uses CP-OFDM to transmit UL data on the physical uplink channel (analogous to LTE PUSCH), regardless of the transmission rank (number of transmission layers). When the UE is configured with single-stream transmission (non-UL SU-MIMO, without rank adaptation capability), the UE can be configured with either CP-OFDM or DFT-S-OFDM. This configuration can be signaled via higher-layer (RRC) signaling, MAC control element (MAC CE), or L1DL control signaling (included in the UL-related DCI).

[0209] In a variant of implementation 5.1 (implementation 5.2), for single-stream transmission, the UE can select its own multiple access scheme (waveform) via uplink channel (to the network or gNB) signaling, rather than receiving configuration signaling. This signaling can be included as part of UL data transmission or as a separate UL transmission (such as a transmission on the UL control channel).

[0210] In another variation of Implementation 5.1 (Implementation 5.3), in addition to the description of Implementation 5.1, the following additional UE processing is supported. When the UE is configured with UL SU-MIMO, a fallback transmission scheme based on DFT-S-OFDM single-stream transmission is supported. This fallback transmission can be dynamically scheduled for the UE via a UL-related DCI different from that used for UL SU-MIMO transmission. The size of this fallback DCI can be significantly smaller than the size of the UL SU-MIMO transmission and is located in the same search space as or a different search space (e.g., a common search space) than the search space used for UL SU-MIMO transmission. This fallback transmission scheme can be the same as or different from the fallback transmission scheme used for single-stream transmission associated with non-UL SU-MIMO transmission. For example, this transmission scheme can be used when a UE configured with UL SU-MIMO transmission is in a coverage-limited situation.

[0211] In another implementation (5.4), when the UE is configured with UL SU-MIMO, the UE uses CP-OFDM for rank-2 (dual-layer transmission) and above to transmit UL data on the physical uplink channel (analogous to LTE PUSCH). For rank-1 (single-layer transmission), the UE can be configured to transmit using either CP-OFDM or DFT-S-OFDM. This configuration can be signaled via higher-layer (RRC) signaling, MAC CE, or L1 DL control signaling. For the last scheme (via L1 DL control signaling), the UL-related DCI associated with UL SU-MIMO transmission includes a one-bit DCI field indicating which waveform (CP-OFDM or DFT-S-OFDM) is used when the value of RI is 1, or these two assumptions (CP-OFDM or DFT-S-OFDM) are jointly encoded with other assumptions such as RI and / or precoding assumptions.

[0212] Additionally, when the UE transmits using DFT-S-OFDM, a single precoder (frequency-nonselective precoder) is used.

[0213] For this implementation, when the UE is configured with single-stream transmission (non-UL SU-MIMO, without rank adaptive capability), the UE can be configured using CP-OFDM or DFT-S-OFDM. Similarly, this configuration can be signaled via higher-layer (RRC) signaling, MAC control element (MAC CE), or L1 DL control signaling (included in UL-related DCI).

[0214] For all the above implementations, whenever DFT-S-OFDM is used, a single-carrier version of DFT-S-OFDM (single-carrier FDMA, SC-FDMA) in which the UE is configured to transmit over a continuous set of PRBs can be used.

[0215] For all the above implementations, whenever a single-stream transmission is used, transmission diversity or single-port transmission can be used.

[0216] The name of the UL transmission channel or waveform is exemplary and may be replaced with other names or labels without changing the substance and / or function of the implementation.

[0217] Figure 9 A flowchart of an exemplary method 900 according to an embodiment of the present disclosure is shown, wherein a UE receives a UL license for UL transmission, the UL license for UL transmission including pre-encoded information fields associated with a plurality of pre-encoded encoders. For example, method 900 may be performed by UE 116.

[0218] Method 900 begins with the UE receiving a UL license for UL transmission (step 901) and decoding a precoding information field in the DCI associated with the UL license, wherein the precoding information field includes at least a PMI corresponding to a plurality of precoders (step 902). The composition of the precoding information field depends on the function of the PMI (step 903). If the PMI is used for subband precoding indication, the number of PMIs is at least equal to the number of precoders, and at least one PMI is associated with a subband corresponding to at least one RB (step 904). In one option, as indicated in the UL Resource Allocation (RA) field of the DCI, the number of PMIs may be fixed, and the number of RBs for each subband depends on the allocated RBs. For example, the number of PMIs is at least two, and the DCI also includes a subband indicator field for one of the PMIs. In another option, at least one PMI associated with a subband is transmitted separately from the DCI including the RA field. If the PMI is used for precoder group indication, the number of PMIs is one, and the PMI indication includes a group of multiple precoders (step 905). In this scenario, the UE selects a precoder from the group, or obtains a precoder from a combination of at least two precoders in the group, for use in licensed UL transmissions. Based on this function, a precoder is determined for each of the allocated RBs (step 906). The UE further precodes the data stream and then transmits the data stream on the UL channel (step 907). The UL channel may be a UL control channel (analogous to LTE PUCCH), a UL data channel (analogous to LTE PUSCH), or a combination of both.

[0219] Figure 10A flowchart of an exemplary method according to an embodiment of this disclosure is shown, wherein the BS generates a precoded information field having at least one PMI (labeled UE-k) for the UE. For example, method 1000 may be performed by BS 102.

[0220] Method 1000 begins with the BS generating a precoding information DCI field for UE-k with at least one PMI (step 1001). The composition of the precoding information field depends on the function of the PMI (step 1002). If the PMI is used for subband precoding indication, the number of PMIs is at least equal to the number of precoders, and at least one PMI is associated with a subband corresponding to at least one RB (step 1003). In one option, as indicated in the UL Resource Allocation (RA) field of the DCI, the number of PMIs may be fixed, and the number of RBs for each subband depends on the allocated RBs. For example, the number of PMIs is at least two, and the DCI also includes a subband indicator field for one of the PMIs. In another option, at least one PMI associated with a subband is transmitted separately from the DCI including the RA field. If the PMI is used for precoder group indication, the number of PMIs is one, and the PMI indication includes a group of multiple precoders (step 1004). Based on this function, the BS generates a UL license with DCI for use in UL transmission to UE-k (step 1005), and transmits the UL license to UE-k on the DL channel (step 1006). This transmission can be accomplished via a combination of the DL control channel (simulated as LTE PDCCH or ePDCCH) or the DL control channel and the DL data channel (simulated as LTE PDSCH).

[0221] Although Figure 9 and Figure 10 Examples of methods for receiving configuration information and configuring the UE are shown respectively, but it is possible to modify them. Figure 9 and Figure 10 Various changes can be made. For example, although shown as a series of steps, the various steps in each figure may overlap, occur in parallel, occur in different orders, occur multiple times, or not be performed in one or more embodiments.

[0222] While this disclosure has been described by way of exemplary embodiments, various changes and modifications may be made or suggested to those skilled in the art. This disclosure is intended to include such changes and modifications that fall within the scope of the appended claims.

Claims

1. A method for transmitting uplink data by a user equipment (UE), the method comprising: Receive uplink UL configuration information from the base station; Based on the UL configuration information, determine the UL transmission waveform between the Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) waveform and the Discrete Fourier Transform-Spread Spectrum-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) waveform; and The uplink data is transmitted using the aforementioned transmission waveform. The CP-OFDM waveform or the DFT-S-OFDM waveform is configured to transmit the uplink data when the number of UL transport layers on the physical UL channel is 1.

2. The method according to claim 1, wherein, When the number of UL transport layers on the physical UL channel is greater than 1, only the CP-OFDM waveform is configured.

3. The method according to claim 1, wherein, The UL configuration information is received via higher-level signaling.

4. The method according to claim 1, wherein, The uplink data includes the sounding reference signal (SRS).

5. A user equipment (UE), comprising: transceiver; as well as A processor, operatively connected to the transceiver, The processor is configured to: Receive uplink UL configuration information from the base station; Based on the UL configuration information, determine the UL transmission waveform between the Cyclic Prefix-Orthogonal Frequency Division Multiplexing (CP-OFDM) waveform and the Discrete Fourier Transform-Spread Spectrum-Orthogonal Frequency Division Multiplexing (DFT-S-OFDM) waveform; and Uplink data is transmitted using the aforementioned transmission waveform. The CP-OFDM waveform or the DFT-S-OFDM waveform is configured to transmit the uplink data when the number of UL transport layers on the physical UL channel is 1.

6. The UE according to claim 5, wherein, When the number of UL transport layers on the physical UL channel is greater than 1, only the CP-OFDM waveform is configured.

7. The UE according to claim 5, wherein, The UL configuration information is received via higher-level signaling.

8. The UE according to claim 5, wherein, The uplink data includes the sounding reference signal (SRS).

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