Method and base station for enhancing multi-user MIMO through channel state information reporting

Abstract

The present disclosure relates to enhancing multi-user MIMO through channel state information reporting. Methods and systems for configuring multi-user multiple input multiple output (MU-MIMO) operations by a base station and multiple UEs include: requesting sounding reference signal (SRS) or channel state information (CSI) data from each of the multiple UEs; configuring a precoder matrix based on the SRS or CSI data from each UE, the precoder matrix allocating multiple precoded CSI reference signal (CSI-RS) resources for each UE; scheduling the precoded CSI-RS resources for each UE; receiving a CQI report from each UE based on the precoded CSI-RS resource received by the corresponding UE; generating a CQI matrix from the CQI report of each UE; selecting a UE subset from the multiple UEs based on the CQI matrix; and scheduling DL resources for the UE subset, the DL resources including reference signals.

Description

[0001] Priority claim

[0002] This application claims priority under 35 U.S.C. §119(e) to U.S. patent application serial number 63 / 248,419 filed on September 24, 2021, the entire contents of which are hereby incorporated by reference into this document. Technical Field

[0003] The present disclosure relates generally to wireless communications. Background Art

[0004] For fifth generation (5G) new radio (NR) networks, multi-user multiple input multiple output (MU-MIMO) enables a base station (e.g., a node, an evolved node eNB, a next generation node gNB, etc.) to send data streams to multiple users simultaneously on the same time-frequency resources. MU-MIMO enhances network or cell throughput. In particular, in high correlation channel scenarios, the UE supports a limited number of download (DL) data streams, and therefore the network switches from single-user MIMO (SU-MIMO) to MU-MIMO, thereby providing data streams to different users with low cross-correlation due to the physical distance between the users. In general, MU-MIMO increases the number of resources by increasing the spatial dimension. For example, by using a time-frequency space grid instead of a time-frequency grid, the same UE has more resources to use, thereby increasing the throughput of the UE. Summary of the invention

[0005] This patent application describes a data processing system and process for enhancing multi-user MIMO through channel state information (CSI) reporting. As described herein, a UE is configured to assist a base station (e.g., a gNB, a node, an eNB, etc.) in selecting one or more UEs from a set of UEs for MU-MIMO using CSI reports. Alternatively or additionally, the base station is configured to generate (e.g., refine, configure, determine, etc.) a DL precoder to improve MU-MIMO operation, such as increasing overall data throughput, selecting better UEs from a set of available UEs, and minimizing interference between UEs connected to the base station during MU-MIMO operation of the base station.

[0006] Typically, 5G NR provides MIMO enhancements to enable MU-MIMO. For example, Type II CSI feedback enables the UE to send more accurate channel state feedback (e.g., CSI). NR Type II refers to the use of a Type II codebook, in which a beam group is selected for a channel and each beam in the group is linearly combined for transmitting data. In contrast, the NR Type I codebook refers to the selection of a single beam in a beam group for communication. The precoder matrix (or precoder) indicates which beams of the UE are selected for communication, and therefore can indicate the co-phase and amplitude scaling of the selected beams of the corresponding UE. The UE can report this configuration to the base station using a precoding matrix indicator (PMI).

[0007] CSI is used to determine the downlink (DL) precoder for performing MU-MIMO. Typically, in a time division duplex (TDD) system, the UE uses an uplink (UL) sounding reference signal (SRS) to estimate the quality of the downlink channel, assuming channel reciprocity. The UE sends this data to the base station, which designs the MU-MIMO DL precoder based on the DL channel estimate from each UE. In some specific implementations, each UE designs a corresponding precoder. The non-zero power CSI reference signal (NZP-CSI-RS) supports both channel measurement and interference measurement.

[0008] For MU-MIMO, the base station receives a set of estimated DL channels (called super channels) between a given number (K) of UEs and the base station. The super channel is based on the number of antennas at each UE and the base station. The base station receives information indicating the state of each UE channel that enables the super channel to generate a DL precoder for MU-MIMO, so that each UE receives the corresponding data stream with limited interference from the data streams of other connected UEs. In some specific implementations, the base station schedules a subset of available UEs for MU-MIMO.

[0009] The systems and processes described in this document can achieve one or more of the following advantages, as well as other advantages. The proposed system and method enable a base station to accurately estimate the super channel of a selected UE group (including a set of all available UEs or a subset of available UEs) for MU-MIMO. The methods and systems disclosed herein enable a base station to determine a precoder based on a super channel of a set of potentially connected UEs for MU-MIMO. The base station precoder based on the super channel is more accurate than the UE-based precoder generation. For example, for Type II CSI feedback, each UE sends the generated precoder to the base station. The precoder generated by the UE is typically based on the channel between the UE and the base station, not the super channel. In addition, in order to limit overhead, the precoder generated by the UE is quantized, which results in some information loss. In addition, for the case of SRS-based channel estimation, each DL channel is estimated by the base station from the UL SRS signal of each corresponding UE. However, due to different radio frequency (RF) impairments at the UE and the base station, the DL channel is not the same as the UL channel. The methods and systems described herein enable the DL channel to be estimated in a manner that captures the interference experienced by the UE. Even with calibration, estimating the DL channel from the UL signal as is typically performed may not capture the interference experienced at the UE.

[0010] The technology disclosed in this application is implemented through one or more specific implementations, which are described in the Examples section of this document.

[0011] The details of one or more specific implementations are described in the following figures and detailed description. The technology described herein can be implemented by one or more wireless communication systems, components of wireless communication systems (e.g., stations, access points, user equipment, base stations, etc.), or other systems, devices, methods, or non-transitory computer-readable media, etc. Other features and advantages will be apparent in the detailed description and drawings and claims. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] Figure 1 An exemplary wireless communication system according to various implementations herein is shown.

[0013] Figure 2 Examples of computing devices according to various implementations are shown.

[0014] Figure 3 It shows that the UE such as Figure 1 to Figure 2 An example of the UE performing CSI reporting.

[0015] Figure 4 An exemplary process for enhancing MU-MIMO through CSI reporting is shown.

[0016] Figure 5An exemplary process for selecting a subset of available UEs for enhanced MU-MIMO is shown.

[0017] Fig. 6A An exemplary process for enhancing precoder refinement for MU-MIMO through CSI reporting is shown.

[0018] Figure 6B An exemplary process for enhancing precoder refinement for MU-MIMO through CSI reporting is shown.

[0019] Like reference symbols in the various drawings indicate like elements. DETAILED DESCRIPTION

[0020] Figure 1 An example of a wireless communication system 100 is illustrated. For convenience and not limitation, the exemplary system 100 is described in the context of Long Term Evolution (LTE) and fifth generation (5G) new air interface (NR) communication standards, as defined by the third generation partnership project (3GPP) technical specifications. More specifically, the wireless communication system 100 is described in the context of a non-standalone (NSA) network that combines both LTE and NR, such as an E-UTRA (Evolved Universal Terrestrial Radio Access)-NR dual connection (EN-DC) network and a NE-DC network. However, the wireless communication system 100 may also be an independent (SA) network that combines only NR. In addition, other types of communication standards are also possible, including future 3GPP systems (e.g., sixth generation (6G)) systems, IEEE 802.16 protocols (e.g., WMAN, WiMAX, etc.), etc.

[0021] like Figure 1 As shown, system 100 includes UE 101a and UE 101b (collectively referred to as "UE 101"). In this example, UE 101 is shown as a smart phone (e.g., a handheld touch screen mobile computing device that can connect to one or more cellular networks), but may also include any mobile or non-mobile computing device, such as a consumer electronic device, a mobile phone, a smart phone, a feature phone, a tablet computer, a wearable computer device, a personal digital assistant (PDA), a pager, a wireless handheld device, a desktop computer, a laptop computer, an in-vehicle infotainment (IVI), an in-vehicle entertainment (ICE) device, an instrument panel (IC), a head-up display (HUD) device, an on-board diagnostic (OBD) device, a dashtop mobile equipment (DME), a mobile data terminal (MDT), an electronic engine management system (EEMS), an electronic / engine electronic control unit (ECU), an electronic / engine electronic control module (ECM), an embedded system, a microcontroller, a control module, an engine management system (EMS), a networked or "smart" appliance, an MTC device, an M2M, an IoT device, etc.

[0022] UE 101 may be configured to be connected to, for example, communicatively coupled to, RAN 110. In a specific implementation, RAN 110 may be NG RAN or 5G RAN, E-UTRAN or a traditional RAN, such as UTRAN or GERAN. As used herein, the term "NG RAN" or the like may refer to RAN 110 operating in NR or 5G system 100, while the term "E-UTRAN" or the like may refer to RAN 110 operating in LTE or 4G system or 5G system 100. Multiple UEs 101 utilize connections (or channels) 103 and 104, respectively, each connection including a physical communication interface or layer (discussed in further detail below).

[0023] In this example, connection 103 and connection 104 are shown as air interfaces to achieve communication coupling, and may be consistent with a cellular communication protocol, such as a GSM protocol, a CDMA network protocol, a PTT protocol, a POC protocol, a UMTS protocol, a 3GPP LTE protocol, an advanced long term evolution (LTE-A) protocol, an LTE-based unlicensed spectrum access (LTE-U), a 5G protocol, a NR protocol, an NR-based unlicensed spectrum access (NR-U) protocol, and / or any other communication protocol discussed herein. In a specific implementation, UE 101 may directly exchange communication data via a ProSe interface 105. The ProSe interface 105 may alternatively be referred to as a SL interface 105, and may include one or more logical channels, including but not limited to PSCCH, PSSCH, PSDCH, and PSBCH.

[0024] UE 101b is shown configured to access AP 106 (also referred to as "WLAN node 106," "WLAN 106," "WLAN terminal 106," "WT 106," etc.) via connection 107. Connection 107 may include a local wireless connection, such as a connection consistent with any IEEE 802.11 protocol, wherein AP 106 will include Wireless Fidelity. router. In this example, AP 106 is shown connected to the Internet without being connected to the core network of the wireless system (described in further detail below). In various specific implementations, UE 101b, RAN 110, and AP 106 may be configured to utilize LWA operation and / or LWIP operation. LWA operation may involve UE 101b in RRC_CONNECTED state being configured by RAN nodes 111a-b to utilize radio resources of LTE and WLAN. LWIP operation may involve UE 101b using WLAN radio resources (e.g., connection 107) via an IPsec protocol tunnel to authenticate and encrypt packets (e.g., IP packets) sent over connection 107. IPsec tunneling may include encapsulating the entire original IP packet and adding a new packet header, thereby protecting the original header of the IP packet.

[0025] The RAN 110 includes one or more AN nodes or RAN nodes 111a and 111b (collectively referred to as "RAN nodes 111") that enable connections 103 and 104. As used herein, the terms "access node", "access point", etc. may describe equipment that provides radio baseband functions for data and / or voice connections between a network and one or more users. These access nodes may be referred to as BS, gNB, RAN nodes, eNB, NodeB, RSU, TRxP or TRP, etc., and may include ground stations (e.g., terrestrial access points) or satellite stations that provide coverage within a geographic area (e.g., a cell). As used herein, the terms "NG RAN node" and the like may refer to a RAN node 111 (e.g., a gNB) operating in an NR or 5G system 100, while the terms "E-UTRAN node" and the like may refer to a RAN node 111 (e.g., an eNB, gNB, etc.) operating in an LTE or 4G system or a 5G system 100. According to various specific implementations, the RAN node 111 may be implemented as one or more of dedicated physical devices such as a macrocell base station and / or a low power (LP) base station for providing a femtocell, picocell or other similar cell with a smaller coverage area, smaller user capacity or higher bandwidth than a macrocell.

[0026] In some implementations, all or part of the RAN node 111 may be implemented as one or more software entities running on a server computer as part of a virtual network that may be referred to as a CRAN and / or a virtual baseband unit pool (vBBUP). In these implementations, the CRAN or vBBUP may implement a RAN functional split, such as a PDCP split, where the RRC and PDCP layers are operated by the CRAN / vBBUP, while other L2 protocol entities are operated by individual RAN nodes 111; a MAC / PHY split, where the RRC, PDCP, RLC, and MAC layers are operated by the CRAN / vBBUP, and the PHY layer is operated by individual RAN nodes 111; or a "lower PHY" split, where the RRC, PDCP, RLC, MAC layers, and upper portions of the PHY layers are operated by the CRAN / vBBUP, and the lower portions of the PHY layers are operated by individual RAN nodes 111.

[0027] Any of the RAN nodes 111 may serve as a termination point for the air interface protocol and may be the first point of contact for the UE 101. In some implementations, any of the RAN nodes 111 may perform various logical functions of the RAN 110, including but not limited to functions of a radio network controller (RNC), such as radio bearer management, uplink and downlink dynamic radio resource management and data packet scheduling, and mobility management.

[0028] In some implementations, UE 101 may be configured to communicate with each other or with any of RAN nodes 111 on a multi-carrier communication channel using OFDM communication signals according to various communication techniques, such as but not limited to OFDMA communication techniques (e.g., for downlink communication) or SC-FDMA communication techniques (e.g., for uplink and ProSe or sidelink communication), although the scope of the implementation is not limited in this respect. OFDM signals may include multiple orthogonal subcarriers.

[0029] In some implementations, a downlink resource grid may be used for downlink transmissions from any of the RAN nodes 111 to the UE 101, while uplink transmissions may utilize similar techniques. The grid may be a time-frequency grid, referred to as a resource grid or a time-frequency resource grid, which is a physical resource in the downlink in each time slot. For OFDM systems, such a time-frequency plane representation is common practice, which makes radio resource allocation intuitive. Each column and each row of the resource grid corresponds to an OFDM symbol and an OFDM subcarrier, respectively. The duration of the resource grid in the time domain corresponds to a time slot in a radio frame. The smallest time-frequency unit in the resource grid is represented as a resource element. Each resource grid includes a plurality of resource blocks, which describe the mapping of certain physical channels to resource elements. Each resource block includes a set of resource elements; in the frequency domain, this may represent the minimum amount of resources that can currently be allocated. Such resource blocks are used to transmit several different physical downlink channels.

[0030] According to various specific implementations, UE 101 and RAN node 111 communicate data (e.g., transmit data and receive data) through a licensed medium (also referred to as a "licensed spectrum" and / or a "licensed band") and an unlicensed shared medium (also referred to as an "unlicensed spectrum" and / or an "unlicensed band"). The licensed spectrum may include channels operating in a frequency range of approximately 400 MHz to approximately 3.8 GHz, and the unlicensed spectrum may include a 5 GHz band. NR in the unlicensed spectrum may be referred to as NR-U, and LTE in the unlicensed spectrum may be referred to as LTE-U, License Assisted Access (LAA), or MulteFire.

[0031] To operate in the unlicensed spectrum, the UE 101 and the RAN node 111 may operate using LAA, eLAA, and / or feLAA mechanisms. In these implementations, the UE 101 and the RAN node 111 may perform one or more known medium sensing operations and / or carrier sensing operations to determine whether one or more channels in the unlicensed spectrum are unavailable or otherwise occupied before transmitting in the unlicensed spectrum. The medium / carrier sensing operations may be performed according to a listen-before-talk (LBT) protocol.

[0032] LBT is a mechanism by which equipment (e.g., UE 101, RAN node 111, etc.) senses the medium (e.g., a channel or carrier frequency) and transmits when the medium is sensed to be idle (or when a particular channel in the medium is sensed to be unoccupied). The medium sensing operation may include a CCA that utilizes at least an ED to determine whether other signals are present on the channel in order to determine whether the channel is occupied or idle. The LBT mechanism allows cellular / LAA networks to coexist with existing systems in unlicensed spectrum and with other LAA networks. ED may include sensing RF energy over a period of time on an expected transmission band and comparing the sensed RF energy to a predefined or configured threshold.

[0033] The PDSCH carries user data and higher layer signaling to multiple UEs 101. The PDCCH carries, among other information, information about the transport format and resource allocation related to the PDSCH channel. It may also inform multiple UEs 101 about the transport format, resource allocation, and HARQ information related to the uplink shared channel. Typically, downlink scheduling (allocation of control and shared channel resource blocks to UEs 101b within a cell) may be performed at any one of the RAN nodes 111 based on channel quality information fed back from any one of the UEs 101. Downlink resource allocation information may be sent on the PDCCH for (e.g., allocated to) each of the UEs 101.

[0034] PDCCH uses CCE to transmit control information. Before being mapped to resource elements, the PDCCH complex-valued symbols can first be organized into quadruplets, which can then be arranged using a sub-block interleaver for rate matching. One or more of these CCEs can be used to transmit each PDCCH, where each CCE can correspond to a set of nine physical resource elements, called REGs. Four quadrature phase shift keying (QPSK) symbols can be mapped to each REG. Depending on the size of the DCI and channel conditions, one or more CCEs can be used to transmit the PDCCH. There may be four or more different PDCCH formats defined in LTE with different numbers of CCEs (e.g., aggregation levels, L=1, 2, 4, or 8).

[0035] Some implementations may use the concept of resource allocation for control channel information, which is an extension of the above concept. For example, some implementations may utilize EPDCCH that uses PDSCH resources for control information transmission. One or more ECCEs may be used to transmit EPDCCH. Similar to the above, each ECCE may correspond to nine sets of four physical resource elements, referred to as EREGs. In some cases, ECCEs may have other numbers of EREGs.

[0036] The RAN nodes 111 may be configured to communicate with each other via an interface 112. In a specific implementation where the system 100 is an LTE system, the interface 112 may be an X2 interface 112. The X2 interface may be defined between two or more RAN nodes 111 (e.g., two or more eNBs, etc.) connected to the EPC 120, and / or between two eNBs connected to the EPC 120. In some specific implementations, the X2 interface may include an X2 user plane interface (X2-U) and an X2 control plane interface (X2-C). The X2-U may provide a flow control mechanism for user packets transmitted over the X2 interface, and may be used to transmit information about the delivery of user data between eNBs. For example, the X2-U may provide specific sequence number information about user data transmitted from the MeNB to the SeNB; information about the successful in-sequence delivery of PDCP PDUs from the SeNB to the UE 101 for user data; information about PDCP PDUs that are not delivered to the UE 101; information about the current minimum expected buffer size at the SeNB for transmitting user data to the UE; and the like. X2-C can provide intra-LTE access mobility functions, including context transfer from source eNB to target eNB, user plane transmission control, etc.; load management functions; and inter-cell interference coordination functions.

[0037] In a specific implementation where the system 100 is a 5G or NR system, the interface 112 may be an Xn interface 112. The Xn interface is defined between two or more RAN nodes 111 (e.g., two or more gNBs, etc.) connected to the 5GC 120, between a RAN node 111 (e.g., a gNB) and an eNB connected to the 5GC 120, and / or between two eNBs connected to the 5GC 120. In some specific implementations, the Xn interface may include an Xn user plane (Xn-U) interface and an Xn control plane (Xn-C) interface. The Xn-U may provide non-guaranteed delivery of user plane PDUs and support / provide data forwarding and flow control functions. The Xn-C may provide management and error handling functions for managing the functions of the Xn-C interface; mobility support for UE 101 in a connected mode (e.g., CM-CONNECTED) includes functions for managing UE mobility in a connected mode between one or more RAN nodes 111. The mobility support may include context transfer from the old (source) serving RAN node 111 to the new (target) serving RAN node 111; and control of the user plane tunnel between the old (source) serving RAN node 111 and the new (target) serving RAN node 111. The protocol stack of Xn-U may include a transport network layer built on an Internet Protocol (IP) transport layer, and a GTP-U layer on top of a UDP and / or IP layer for carrying user plane PDUs. The Xn-C protocol stack may include an application layer signaling protocol (referred to as the Xn Application Protocol (Xn-AP)) and a transport network layer built on SCTP. SCTP may be on top of the IP layer and may provide guaranteed delivery of application layer messages. In the transport IP layer, point-to-point transport is used to deliver signaling PDUs. In other specific implementations, the Xn-U protocol stack and / or the Xn-C protocol stack may be the same or similar to the user plane and / or control plane protocol stacks shown and described herein.

[0038] RAN 110 is shown as being communicatively coupled to a core network, in this specific implementation, to a core network (CN) 120. CN 120 may include a plurality of network elements 122 configured to provide various data and telecommunication services to customers / subscribers (e.g., users of a plurality of UEs 101) connected to CN 120 via RAN 110. The components of CN 120 may be implemented in one physical node or separate physical nodes, which include components for reading and executing instructions from a machine-readable or computer-readable medium (e.g., a non-transitory machine-readable storage medium). In some specific implementations, NFV may be used to virtualize any or all of the above-mentioned network node functions via executable instructions stored in one or more computer-readable storage media (described in further detail below). A logical instance of CN 120 may be referred to as a network slice, and a logical instance of a portion of CN 120 may be referred to as a network sub-slice. NFV architecture and infrastructure may be used to virtualize one or more network functions onto physical resources comprising a combination of industry-standard server hardware, storage hardware, or switches (alternatively performed by proprietary hardware). In other words, the NFV system may be used to perform a virtual or reconfigurable implementation of one or more EPC components / functions.

[0039] Generally speaking, the application server 130 may be an element that provides applications that use IP bearer resources with the core network (e.g., UMTS PS domain, LTE PS data services, etc.). The application server 130 may also be configured to support one or more communication services for the UE 101 via the EPC 120 (e.g., VoIP sessions, PTT sessions, group communication sessions, social network services, etc.).

[0040] In a specific implementation, CN 120 may be a 5GC (referred to as “5GC 120”, etc.), and RAN 110 may be connected to CN 120 via an NG interface 113. In a specific implementation, NG interface 113 may be divided into two parts: an NG user plane (NG-U) interface 114, which carries traffic data between RAN node 111 and UPF; and an S1 control plane (NG-C) interface 115, which is a signaling interface between RAN node 111 and AMF.

[0041] In a specific implementation, CN 120 may be a 5G CN (referred to as “5GC 120”, etc.), while in other specific implementations, CN 120 may be an EPC. In the case where CN 120 is an EPC (referred to as “EPC 120”, etc.), RAN 110 may be connected to CN 120 via an S1 interface 113. In a specific implementation, S1 interface 113 may be divided into two parts: an S1 user plane (S1-U) interface 114, which carries traffic data between RAN node 111 and S-GW; and an S1-MME interface 115, which is a signaling interface between RAN node 111 and MME.

[0042] Figure 2 Examples of platform 200 (or "device 200") according to various specific implementations are illustrated. In specific implementations, computer platform 200 may be suitable for use as UE 101, application server, and / or any other element / device discussed herein. Platform 200 may include any combination of components shown in the examples. The components of platform 200 may be implemented as integrated circuits (ICs), parts of ICs, discrete electronic devices, or other modules, logical components, hardware, software, firmware, or combinations thereof adapted in computer platform 200, or as components otherwise combined within the framework of a larger system. Figure 2 The block diagram is intended to show a high-level view of the components of computer platform 200. However, some of the components shown may be omitted, additional components may be present, and different arrangements of the components shown may occur in other implementations.

[0043] The application circuit 205 includes circuits such as, but not limited to, one or more processors (or processor cores), cache memory, and one or more of an LDO, an interrupt controller, a serial interface (such as SPI), I2C or a general purpose programmable serial interface module, an RTC, a timer-counter (including an interval timer and a watchdog timer), a general purpose I / O, a memory card controller (such as an SD MMC or similar controller), a USB interface, a MIPI interface, and a JTAG test access port.

[0044] The processor of the application circuit may include, for example, one or more processor cores, one or more application processors, one or more GPUs, one or more RISC processors, one or more ARM processors, one or more CISC processors, one or more DSPs, one or more FPGAs, one or more PLDs, one or more ASICs, one or more microprocessors or controllers, multi-threaded processors, ultra-low voltage processors, embedded processors, some other known processing elements, or any suitable combination thereof. In some specific implementations, the application circuit may include or may be a dedicated processor / controller for operating according to various specific implementations herein.

[0045] As an example, the processor of the application circuit 205 may include an Apple A series processor. The processor of the application circuit 205 may also be one or more of the following: based on Architecture Core TM Processors such as Quark TM 、Atom TM , i3, i5, i7 or MCU class processors, or available from Santa Clara, CA company( Another such processor is Intel Corporation, Santa Clara, CA); Advanced Micro Devices (AMD) Processor or Accelerated Processing Unit (APU); from Snapdragon by Technologies, Inc. TM Processor, Texas Instruments, Open Multimedia Applications Platform(OMAP) TM processors; MIPS-based designs from MIPS Technologies, Inc., such as the MIPS Warrior M-class, Warrior I-class, and Warrior P-class processors; ARM-based designs licensed from ARM Holdings, Ltd., such as the ARM Cortex-A, Cortex-R, and Cortex-M series processors; etc. In some implementations, the application circuit 205 can be part of a system on a chip (SoC), in which the application circuit 205 and other components are formed as a single integrated circuit.

[0046] Additionally or alternatively, the application circuit 205 may include circuits such as, but not limited to, one or more field programmable devices (FPDs) such as FPGAs, programmable logic devices (PLDs) such as complex PLDs (CPLDs), high capacity PLDs (HCPLDs), ASICs such as structured ASICs, programmable SoCs (PSoCs), and the like.

[0047] Baseband circuit 210 may be implemented, for example, as a solder-in substrate including one or more integrated circuits, a single packaged integrated circuit soldered to a main circuit board, or a multi-chip module containing two or more integrated circuits.

[0048] The RFEM 215 may include a millimeter wave (mmWave) RFEM and one or more sub-millimeter wave radio frequency integrated circuits (RFICs). In some implementations, the one or more sub-millimeter wave RFICs may be physically separated from the mmWave RFEM. The RFIC may include connections to one or more antennas or antenna arrays, and the RFEM may be connected to multiple antennas. In alternative implementations, both mmWave and sub-millimeter wave radio functionality may be implemented in the same physical RFEM 215 incorporating both mmWave antennas and sub-millimeter waves.

[0049] The memory circuit 220 may include any number and type of memory devices for providing a certain amount of system memory. For example, the memory circuit 220 may include one or more of the following: volatile memory including random access memory (RAM), dynamic RAM (DRAM) and / or synchronous dynamic RAM (SDRAM), non-volatile memory (NVM) including high-speed electrically erasable memory (commonly referred to as flash memory), phase change random access memory (PRAM), magnetoresistive random access memory (MRAM), etc.

[0050] Removable memory circuitry 223 may include devices, circuitry, housings / casings, ports or receptacles, etc., for coupling portable data storage devices to platform 200. These portable data storage devices may be used for mass storage, and may include, for example, flash memory cards (e.g., Secure Digital (SD) cards, micro SD cards, xD picture cards, etc.), as well as USB flash drives, optical disks, external HDDs, etc.

[0051] The platform 200 may further include an interface circuit (not shown) for connecting external devices to the platform 200. External devices connected to the platform 200 via the interface circuit include a sensor circuit 221 and an electromechanical component (EMC) 222, and a removable memory device coupled to a removable memory circuit 223.

[0052] Sensor circuitry 221 comprises a device, module, or subsystem that is intended to detect events or changes in its environment, and to send information about the detected events (sensor data) to some other device, module, subsystem, etc. Examples of such sensors include, among others: an inertial measurement unit (IMU) including an accelerometer, a gyroscope, and / or a magnetometer; a microelectromechanical system (MEMS) or a nanoelectromechanical system (NEMS) including a three-axis accelerometer, a three-axis gyroscope, and / or a magnetometer; a level sensor; a flow sensor; a temperature sensor (e.g., a thermistor); a pressure sensor; a barometric pressure sensor; a gravity meter; an altimeter; an image capture device (e.g., a camera or a lensless aperture); a light detection and ranging (LiDAR) sensor; a proximity sensor (e.g., an infrared radiation detector, etc.), a depth sensor, an ambient light sensor, an ultrasonic transceiver; a microphone or other similar audio capture device; etc.

[0053] EMC 222 includes devices, modules or subsystems whose purpose is to enable platform 200 to change its state, position and / or orientation or to move or control mechanisms or (sub) systems. In addition, EMC 222 can be configured to generate and send messages / signaling to other components of platform 200 to indicate the current state of EMC 222.

[0054] In some implementations, the interface circuit may connect the platform 200 to the positioning circuit 245. The positioning circuit 245 includes circuits for receiving and decoding signals transmitted / broadcasted by a positioning network of a GNSS. Examples of navigation satellite constellations (or GNSS) may include GPS of the United States, GLONASS of Russia, Galileo system of the European Union, BeiDou navigation satellite system of China, regional navigation systems or GNSS augmentation systems (e.g., NAVIC, QZSS of Japan, DORIS of France, etc.), etc.

[0055] In some implementations, the interface circuit can connect the platform 200 with a near field communication (NFC) circuit 240. The NFC circuit 240 is configured to provide contactless short-range communication based on the radio frequency identification (RFID) standard, where magnetic field sensing is used to enable communication between the NFC circuit 240 and an NFC-enabled device (e.g., an “NFC touch point”) external to the platform 200.

[0056] Driver circuitry 246 may include software and hardware elements for controlling particular devices embedded in, attached to, or otherwise communicatively coupled to platform 200. Driver circuitry 246 may include various drivers to allow other components of platform 200 to interact with or control various input / output (I / O) devices that may be present within or connected to platform 200.

[0057] A power management integrated circuit (PMIC) 225 (also referred to as “power management circuit 225”) can manage the power provided to various components of platform 200. Specifically, PMIC 225 can control power source selection, voltage scaling, battery charging, or DC-DC conversion with respect to baseband circuit 210. PMIC 225 is typically included when platform 200 is capable of being powered by battery 230.

[0058] In some implementations, the PMIC 225 may control or otherwise be part of various power saving mechanisms of the platform 200. For example, if the platform 200 is in the RRC_Connected state, in which the platform is still connected to the RAN node because it expects to receive traffic soon, then after a period of inactivity, the platform may enter a state known as discontinuous reception mode (DRX). During this state, the platform 200 may be powered off for short intervals, thereby saving power. If there is no data traffic activity for an extended period of time, the platform 200 may transition to the RRC_Idle state, in which the device is disconnected from the network and does not perform operations such as channel quality feedback, handover, etc. The platform 200 enters a very low power state and performs paging, in which the device wakes up periodically again to listen to the network, and then powers off again. The platform 200 may not receive data in this state; in order to receive data, the platform must transition back to the RRC_Connected state. Additional power saving modes may prevent the device from using the network for longer than the paging interval (which can range from a few seconds to several hours). During this time, the device is completely unable to connect to the network and can be completely powered off. Any data sent during this time will be significantly delayed, and it is assumed that the delay is acceptable.

[0059] The battery 230 can power the platform 200, but in some examples, the platform 200 can be mounted in a fixed location and can have a power source coupled to a power grid. The battery 230 can be a lithium-ion battery, a metal-air battery such as a zinc-air battery, an aluminum-air battery, a lithium-air battery, etc. In some implementations, such as in V2X applications, the battery 230 can be a typical lead-acid car battery.

[0060] The user interface circuit 250 includes various input / output (I / O) devices present within or connected to the platform 200, and includes one or more user interfaces designed to implement user interaction with the platform 200 and / or peripheral component interfaces designed to implement interaction with peripheral components of the platform 200.

[0061] Figure 3 An example of a MU-MIMO communication environment 300 is shown with two UEs 310, 312. The UEs 310, 312 may include, for example, Figure 1 to Figure 2UE 101a to UE 101b described in the previous section. UE 310, 312 is configured to communicate with a base station (e.g., Figure 1 to Figure 2 11a to one of the nodes 111b described above). UE 310, 312 is configured for Type II CSI feedback. Type II CSI feedback enables each of UE 310, 312 to send more accurate channel state feedback (CSI) 314. The base station uses CSI feedback 314 to generate a DL precoder for MU-MIMO communication with each of UE 310, 312.

[0062] The CSI feedback 314 is shown in two parts. The first part 314a includes a non-zero power CSI reference signal (NZP-CSI-RS) for channel measurement (CM). The second part 314b includes NZP-CSI-RS resources for interference measurement (IM). In a time division duplex (TDD) system, the UE 310, 312 uses an UL sounding reference signal (SRS) to estimate the DL channel, thereby assuming channel reciprocity. The UE 310, 312 can use the corresponding channel estimates to generate corresponding DL precoders, which can each be indicated to the base station using a corresponding PMI.

[0063] The base station is configured to receive a respective channel estimate from each of the UEs 310, 312 and determine a super channel DL estimate for MU-MIMO communications. Rather than using separate precoders for the respective UEs 310, 312, the base station is configured to determine a precoder for each UE, which improves overall MU-MIMO performance, as described herein. The super channel estimate represents an estimate of the overall MU-MIMO channel, taking into account the impact of one UE on another UE for any UE selected for MU-MIMO. The result is that the base station selects a precoder for the respective UEs 310, 312, each precoder limiting interference between UEs while also maximizing throughput for each UE.

[0064] To determine the super channel DL estimate, the base station receives channel estimation information 314 from each UE, including IM 314a and CM 314b. The super channel including the estimated DL channel set between UE (K) and the base station is defined as shown in equation (1):

[0065]

[0066] Where N u is the number of antennas at a UE (such as UE 310, 312), dl is the download, and N bis the number of antennas at the base station. In this particular example, all UEs have the same number of receive antennas. However, this need not be the case. The base station uses (dl) The knowledge of P is used to design the DL precoder P for MU-MIMO (dl) , so that each UE 301, 312 receives the corresponding data stream with limited interference from the data stream of another UE. Although two UEs 310, 312 are shown, the UE set can be increased to ten or more. Additionally or alternatively, the base station can schedule a subset of UEs 310, 312 (e.g., Ks outside of K) for MU-MIMO communication. For example, if there are ten UEs in the set, the UEs 310, 312 can be the selected UE subset.

[0067] Given H (dl) The super channel estimation and the determined MU-MIMO precoder P (dl) , UE 310, 312 may further assist the base station in selecting a subset of UEs for MU-MIMO. UE 310, 312 may also send data to the base station to enable the base station to refine the DL precoder to improve MU-MIMO operation. Typically, for a given DL MU-MIMO precoder and a set of co-scheduled UEs 310, 312, the base station estimates the quality of the MU-MIMO channel by sending NZP-CSI-RS for channel measurement (CM) 314a and NZ-CSI-RS resources for interference measurement (IM) 314b to each UE. In this example, MU-MIMO is performed with two UEs 310, 312, but other numbers of UEs may be used. The base station sends one NZP-CSI-RS for CM 314a and one NZP-CSI-RS for IM 314b for each UE 310, 312. UE 310 uses block 302 to measure the signal power from its own NZP-CSI-RS for CM. UE 310 uses block 304 to measure interference from the NZP-CSI-RS of UE 312. Additionally, UE 312 uses block 306 to measure interference from the NZP-CSI-RS of UE 310. UE 312 uses block 308 to measure signal power from its own NZP-CSI-RS for the CM.

[0068] After measuring each signal, each UE 310, 312 performs post-processing on the measurement results to calculate the relevant channel metric. For example, the channel metric includes the signal to interference plus noise ratio (SINR), the reference signal received power (RSRP), or a similar channel metric. The UE sends feedback to the base station, such as a channel quality indicator (CQI), a rank indicator (RI), and / or a PMI as previously described. The base station derives the MU-MIMO quality based on the CSI report from each respective UE 310, 312.

[0069] The base station is further configured to overcome several limitations imposed by determining the MU-MIMO configuration based on CSI reports from each individual UE 310, 312. For example, the CSI-RS resources may not be precoded. If the CSI-RS resources from each UE are precoded, an analog beamformer may be used instead of a digital beamformer. If an analog beamformer is used, the base station and UE 310, 312 perform SRS-based channel estimation. In addition, a particular CSI report at a given UE may not reflect the impact of co-scheduling other UEs. Typically, a single value is used for each reporting quantity (such as CQI). If the base station co-schedules multiple UEs, the base station may not be able to accurately locate which UE (or UEs) adversely affects MU-MIMO performance and which UE (or UEs) can be scheduled without adversely affecting MU-MIMO performance (or even improving throughput).

[0070] To overcome these potential limitations, a base station is configured as now described. The base station determines a downlink precoder for a given number of UEs (e.g., K UEs). The base station selects a subset of one or more UEs from the given number of UEs for coordinated scheduling for MU-MIMO communication. In general, is the NZP-CSI-RS resource allocated to the kth UE for scheduling MU-MIMO communication. The base station allocates multiple precoded CSI-RS resources for this specific UE, as shown in formula (2):

[0071]

[0072] in It is the encoder of the lth UE among the K UEs. A specific selected UE (e.g., UE 310 or 312) post-processes each CSI-RS measurement result to determine the value of the metric used for CQI selection. The selected UE determines the CQI for each CSI-RS resource. The selected UE reports the determined CQI (in this case, K CQIs) to the base station. Ideally, one determined CQI should be larger and the other CQI value should be smaller because these CQI values ​​correspond to CSI-RS resources precoded in the null space of the UE's channel. Typically, CQI values ​​are from 0 to 15. A low CQI (e.g., 0-3) means that there is a low signal to interference plus noise ratio (SINR) region. A high CQI (e.g., 10-15) means a medium to high SINR operating area. For a given UE-k, CSI-RS resource-k should provide a higher CQI than CSI-RS resource-m, where m=1, 2, ..k-1, k+1, ..K. Resource-k is represented by P k (dl) precoding, the resource is in the direction of the UE-k channel, and resource-m is precoded with P m (dl) precoding, the resource is in the direction of the UE-m channel which is orthogonal to the UE-k channel (e.g., the null space of UE-k). Therefore, with the correct precoding, the CQI k CQI m Much bigger.

[0073] Once the CQI value is determined, the base station determines the set of UEs to be used for MU-MIMO. The base station has K 2 CQI values ​​(e.g., K values ​​per UE). The base station uses the CQI values ​​to determine which UE subset to select. The base station generates a CQI matrix Where [Q] i，k ∈{0, 1, ..., 15}, i, k = 1, 2, ..., K. The diagonal elements of the CQI matrix represent the CQI of the corresponding CSI-RS resource precoded in the direction of the desired channel of each UE (e.g., UE 310, 312). The non-diagonal elements of the CQI matrix represent the CQI of the CSI-RS resource precoded in the zero direction of the channel of the corresponding UE 310, 312.

[0074] The base station is configured to select the UE subset using a selection process, as described in further detail later. For example, the base station may select the UE subset based on the Q sThe utility function of the matrix selects a subset of UEs (such as UEs 310, 312) from the set of UEs. Typically, each UE provides a vector of CQIs (e.g., of length Kx1). The base station constructs a Q matrix (of size KxK). Once the base station selects a subset of UEs, the base station maintains the Q matrix of the selected UEs. s (a matrix subset of Q).

[0075] The base station is configured to refine the MU-MIMO precoder for MU-MIMO communication. The base station generates multiple precoders for the same UE. For example, the base station is configured to switch between a zero forcing (ZF) precoder and a minimum mean square error (MMSE) based precoder. The zero forcing precoder is designed to completely eliminate multi-user interference regardless of noise. The MMSE precoder is designed to minimize the mean square error (MMSE) between the actual transmitted signal and the processed precoded signal; therefore, interference and noise are taken into account. The base station periodically sends precoded CSI-RS resources to the UE and then updates the Q (or Q) of the UE (or a subset of co-scheduled UEs). s ) matrix to generate the precoder.

[0076] To enable UEs to perform MU-MIMO, the base station performs the following actions. The base station performs an optimization process for MU-MIMO UE selection. The purpose of the optimization process is to maximize the utility function of the matrix Q that depends on the set of UEs. The base station determines a specific number K to be selected from the set of K UEs. s In some implementations, the subset K s includes fewer UEs than K. In some implementations, the subset K s Equal to K.

[0077] The optimization process is as follows. Usually, The value of is the selection vector. This means that if the kth UE is selected, then [a] k =1, otherwise 0. Then, Therefore, formula (3) is as follows:

[0078]

[0079] The complexity of this expression depends on the specific utility function used, but the optimization process is generally a combinatorial problem. The utility function may depend on the diagonal elements of the Q matrix to represent the received signal strength at each UE, on the off-diagonal elements to represent the received interference strength at each UE, or on both diagonal and off-diagonal elements. One example includes defining a reward utility function such as If, for each selected UE, the diagonal elements of Q are large and the off-diagonal elements of Q are small, the utility value (or reward) is high.

[0080] In some implementations, the base station performs an iterative process for MU-MIMO UE selection. For example, depending on the base station processing power and time constraints, the maximum number of UEs to be selected may be limited. Therefore, the base station performs a dimensionality reduction step. The dimensionality reduction step may be based on, but not limited to, the received signal power strength of each UE, which is quantified by the diagonal elements of the Q matrix (diag(Q)) and then selects the highest K s ≤K 0 <K value, where K 0 is an adjustment parameter that depends on the base station's capabilities. The base station then stores the corresponding The base station then selects Limited K 0 Select K s A subset of UEs, and by optimizing the utility f similar to formula (3) a (Q 0 ) to obtain the corresponding Q of each selected UE s matrix.

[0081] The base station may then repeatedly select different subsets K from K using random selection or a stopping criterion (eg, stopping further computation once a suitable combination is found). s to achieve the application of each possible combination of UEs or a subset of UE combinations. The base station may then select the one corresponding to the highest calculated utility value f a In some specific implementations, the base station determines f for all UE combinations. a The value of f a In some implementations, the base station sets a threshold r and selects the UE corresponding to the f that exceeds the threshold r. a In this case, the base station may select a subset of UEs without calculating the reward value for each possible combination of UEs. The base station may select any UE combination corresponding to a reward value that satisfies the threshold reward value r, without necessarily selecting the UE combination corresponding to the highest reward value.

[0082] The base station is configured to refine the precoder In some implementations, once the UE set K is determined s , the base station refines the precoder The base station maintains Q after precoding selection. s , and update Q over time s For example, the base station uses periodic CSI-RS resources to periodically monitor the diagonal elements and non-diagonal elements of the CQI matrix of each UE.

[0083] To refine the precoder, the base station may perform the following first process: The base station performs CQI-dependent linear precoding. Considering a general precoder The general precoder consists of two parts: To eliminate inter-UE interference and Used to eliminate interference within the UE. The base station can s In addition, the base station can change the outer precoder according to the non-diagonal elements of Q s The diagonal elements of are used to change the inner precoder. For example, if [Q s ] k，k Higher (for example, greater than 12), the base station uses (e.g., zero forcing) because zero forcing is effective and performs well at high SNRs (e.g., obtains near-optimal or optimal results). However, if [Q s ] k，k decreases over time, the base station updates the inner precoder to use a linear MMSE precoder, which is more robust but more complex (eg, includes additional computations relative to the ZF approach).

[0084] To refine the precoder, the base station may perform the following second process. In this process, the base station uses CQI related triggers for MU-MIMO channel estimation. The base station periodically requests the UE to send non-precoded SRS transmissions or requests the UE to report Type II CSI feedback to estimate the channel. The base station uses these updated values ​​to update the DL precoder. As an alternative to periodic requests that may increase overhead, once the Q s When the element in decreases to below the allowable threshold, the base station triggers an SRS or Type II CSI feedback request. The base station can specify which UEs should transmit SRS or Type II feedback to further reduce bandwidth consumption.

[0085] The base station can use the differential CQI matrix to reduce the overhead of the UE selection process, precoder refinement, or both. s Each element in uses 4 bits because there are 16 CQI indexes. In order to reduce the signaling overhead, the base station uses differential CQI. The differential CQI uses 4 bits for each diagonal element in the diagonal elements and only 2 bits for each non-diagonal element in the non-diagonal elements. In order to use differential CQI, each UE (e.g., UE 310, 312) determines the CQI of the diagonal elements according to formula (5):

[0086]

[0087] Where q(·) is the CQI mapping function. The UE then uses formula (6) to determine the CQI of the off-diagonal elements:

[0088]

[0089] UE determines the difference where q d (·) maps the difference into two bits. In this way, during UE selection, the base station uses the regular CQI report to determine the K to be scheduled by obtaining Q s A subset of UEs (Q s ). The base station then switches to differential CQI mode, where Q s The value of has diagonal values ​​based on 4-bit data and off-diagonal values ​​based on 2-bit data. The differential CQI mode is reported using a new reporting mode such as, for example, reportQuantity=muMimoCqi, where the base station allocates K re-encoded CSI-RS resources for the UE. The UE then only reports the CQI for each CSI-RS resource. In some implementations, an additional higher layer parameter (e.g., isSpatailCqi) is included so that the UE can determine how to report the CQI (e.g., using 4 bits or 2 bits).

[0090] Typically, each UE measures K (e.g., equal to the number of UEs) resources to report back K CQI values. In order to report back K CQI values ​​and use the proposed MU-MIMO enhancement, the base station requests each UE to report K reports. Each report is linked to a precoded, possibly multi-ported CSI-RS resource. The same resource group can be shared across UEs.

[0091] The process that the network can follow to obtain these reports is called the eMU-MIMO process. The eMU-MIMO process includes K resource sets to which CSI-RS resources are allocated by the base station for each UE. Typically, each resource set includes a single and precoded CSI-RS resource. The kth CSI-RS resource is precoded with the DL precoder of the kth UE. The precoder is derived from the channel, which is estimated from the uplink SRS. Each resource set is linked to a single report with reporting quantities criRiCqi. If these criteria are met, the base station constructs a CQI matrix (Q). If a memory device is used to store a utility function of the matrix or Q matrix, and the Q matrix is ​​used in MU-MIMO user scheduling and / or DL ​​MU-MIMO precoding, this indicates that the base station is configuring MU-MIMO as described herein.

[0092] The MU-MIMO scheduling scenario process is performed as now described. In this example, there are two UEs selected from four available UEs. For MU-MIMO operation, each UE generates four reports as requested by the base station or one report for each precoded CSI-RS resource. In this example, the first UE reports CQI = [H, L, L, L], where H and L refer to high and low values, respectively. This is a four-dimensional vector, with the kth element representing the report for the kth precoded CSI-RS resource (e.g., the kth resource is precoded by the DL precoder of the kth UE). The second UE reports CQI = [L, H, L, L]. The third UE and the fourth UE each report CQI = [L, L, L, L] or all low CQI values. For these reports from each UE, the base station schedules the first UE and the second UE because the network is using the CQI matrix in MU-MIMO scheduling selection.

[0093] An exemplary process for MU-MIMO precoder refinement is now described. Once the first UE and the second UE are scheduled, they are still requested to report CQI periodically. The first UE changes CQI(2)=L to CQI(2)=H. In other words, the first UE reports a high CQI to the base station on a second precoded CSI-RS resource that is assumed to be in the null space of the eigenmode of the first UE. The UE therefore indicates that the interference from the second UE has increased, and therefore the first UE reports an increased CQI. The base station then requests each of the first UE and the second UE to send an SRS to update their respective precoders, requesting the second UE to report CQI more frequently, and / or the first UE to experience a reduction in CQI for the second precoded CSI-RS resource. This is because the base station refines the precoder as described herein. The refinement is triggered by the CQI reported by the first UE, so that the precoder refinement depends on the CQI matrix.

[0094] Figure 4 An exemplary process 400 for UE selection and precoder generation by a base station for MU-MIMO operation is shown. In some implementations, a UE may include Figures 1 to 3 In some specific implementations, the base station includes a base station as described in Figure 1 to Figure 2 The nodes 111a to 111b or the network 120.

[0095] Process 400 includes: requesting (402) SRS or Type II CSI feedback for a given number K of UEs by a base station. In some embodiments, the number of UEs includes all UEs in the environment of the base station. In some embodiments, the base station selects a set of available UEs to determine an optimal UE subset for MU-MIMO and / or to determine a precoder refinement for MU-MIMO operation for the selected UEs. As described herein, if the number of available UEs is too large, the base station determines a set of candidate UEs as the UE set K based on the CQI report (e.g., by comparing one or more parameters of the report to one or more variable thresholds). Typically, this initial selection process is a rough approximation of candidate UEs for MU-MIMO operation. One or more parameters of the CQI may include an NZP-CSI-RS for IM and / or an NZP-CSI-RS for CM for the corresponding UE.

[0096] The base station optimizes (404) the initial precoder P (dl) , where P k (dl) =W k (inter) W k (intra) , as described previously. The initial precoder is the DL precoder for K UEs, and the base station then determines which K UEs to co-schedule for MU-MIMO s To obtain a CQI report for each UE, the base station schedules (406) precoded CSI-RS resources for each UE in the environment using an initial precoder. The corresponding UE post-processes each measurement result to derive a metric for CQI selection.

[0097] The base station receives (408) from each UE in the environment a respective CQI report based on the respective received precoded CSI-RS sent to the UE. The base station has K 2 CQI values ​​(K for each UE). For each UE, 1 CQI value should be larger, while K-1 should be smaller, because these CQI values ​​correspond to CSI-RS resources precoded with the null space of the UE's channel.

[0098] The base station generates (410) a CQI matrix Q from the CQI values. In some implementations, the base station generates a utility function based on the CQI matrix Q as described herein. The base station stores the matrix Q and / or the utility function in a memory repository. In some implementations, the base station applies the utility function to optimize the selection of the UE subset Ks as previously described. Figure 5The utility function is further described. For the matrix Q, the diagonal elements represent the CQI of the CSI-RS resources precoded in the direction of the desired channel of the UE, while the non-diagonal elements represent the CQI of the CSI-RS resources precoded in the zero direction of the channel of the UE.

[0099] The base station is configured to select (412) a subset of UEs Ks and maintain a CQI matrix Qs representing the selected subset of UEs Ks. As described herein, the selection is based on a utility / reward function or by testing each combination of values ​​until the best result is determined.

[0100] The base station schedules (414) DL resources for a subset of UEs using MU-MIMO, where the resources include reference signals and data (e.g., PDSCH, PDCCH, etc.). MU-MIMO operation continues with the UE transmitting data to the base station. The base station monitors (416) transmissions from the UE and updates the CQI matrix Qs for the selected subset of UEs based on the data transmissions between the base station and the UE. The base station performs this monitoring to determine whether the selected subset of UEs should be changed or whether the precoder should be reconfigured for the selected subset of UEs. For example, the base station determines (418) whether an element of the CQI matrix Qs is changing. If an element is changing (e.g., the value changes by more than 2 CQI indices), the base station is configured to trigger (420) new reference symbols and / or update the precoder for the selected UE. About FIG. 6A to FIG. 6B Describes updating the precoder.

[0101] Figure 5 An exemplary process 500 for selecting a set of UEs for MU-MIMO is shown. In some implementations, a UE may include Figures 1 to 3 In some specific implementations, the base station includes a base station as described in Figures 1 to 4 The nodes 111a to 111b or the network 120 described above. The selection of UEs by the base station is configured to optimize a utility function or reward function that depends on the value of the CQI report from each UE (e.g., the matrix Q), with K UEs selected from a set of K UEs. s The constraints of each UE.

[0102] The base station is configured to determine (502) which UEs are available in the environment. In one example, the set of available UEs may include any UE from which the base station receives a CQI report. The base station obtains (504) a selection vector. The selection vector is So that if the kth UE is selected, then [a] k =1, otherwise 0. Then, As previously described.

[0103] Compare (506) the number of available UEs with an adjustment parameter K that depends on the base station capabilities or time constraints. If the number of available UEs is too high to apply the utility function, the base station performs (508) a dimensionality reduction of K by picking UEs based on the diagonal of the CQI matrix Q and selecting the highest set of UEs K 0 <= K s < K, where K 0 is the desired number of UEs based on the adjustment parameter, and where Q 0 is the CQI matrix of K 0 UEs. 0

[0104] The base station searches (510) for Ks subsets of K UEs among each reward value of the Qs matrix for different possible UE combinations of K 0 UEs. As described herein, the base station applies the utility function by selecting K 0 (defined by the set 0 ) of UEs and obtains the corresponding Q matrix. The base station determines the reward for each combination of UEs s s If the diagonal elements of Qs are larger and the off-diagonal elements are smaller in relative terms, the value of the reward is higher.

[0105] The base station iterates through the combinations of UEs until an acceptable result is obtained. In a first example, the base station performs an exhaustive search of all available combinations. For example, the base station determines (512) whether all CQI matrices Qs are determined and whether at least one CQI matrix Qs meets a quality threshold. The quality threshold is met when the reward value of the utility function meets the threshold value. In some embodiments, once the reward threshold is met, the base station stops iterating, even if the selected subset Ks does not have the highest possible effect value. The base station selects (514) the subset of UEs Ks associated with the Qs having the best reward value among the Ks subsets searched.

[0106] FIG. 6A to FIG. 6B Exemplary processes 600, 620 include precoder refinement for MU-MIMO operation. In some embodiments, the UE may include Figures 1 to 3 UEs 101a through 101b. In some embodiments, the base station includes nodes 111a through 111b or network 120 as described with respect to Figures 1 to 5 . To refine the precoder for MU-MIMO operation, the base station maintains Q s , and updates it over time as the UE transmits data to the base station.

[0107] For process 600, the base station uses periodic CSI-RS resources to monitor the diagonal and off-diagonal elements of the CQI matrix Qs of the selected UE. The base station performs CQI-dependent linear precoding. As mentioned earlier, the base station change depends on Q s The outer precoder of the off-diagonal elements of s The base station checks (602) the off-diagonal elements of Qs and the diagonal elements of Qs. To optimize (604) the precoder, the base station compares the values ​​of the Qs matrix with a threshold value. If [Q s ] k，k is higher (e.g., meets threshold 606), the base station uses (608) zero-forcing optimization. s ] k，k decreases over time (eg, does not meet threshold 606), the base station updates (610) the inner precoder using a linear MMSE precoder.

[0108] For process 620, the base station uses periodic CSI-RS resources to monitor the diagonal elements and off-diagonal elements of the CQI matrix Qs of the selected UE. The base station determines (622) that the elements of Qs do not meet the threshold. The base station then triggers (624) an SRS or Type II CSI feedback request from the UE based on the elements of Qs not meeting the threshold. This reduces overhead compared to periodic requests for SRS or Type II CSI feedback from the base station. In some specific implementations, the base station may periodically request SRS or Type II CSI feedback to determine whether to update the precoder.

[0109] Example

[0110] In the following sections, additional exemplary embodiments are provided.

[0111] Embodiment 1 includes a base station for configuring a multi-user multiple input multiple output (MU-MIMO) operation between the base station and a plurality of UEs, the base station comprising: a circuit for sending data to the plurality of UEs and receiving data from the plurality of UEs; one or more processing devices; and a memory storing instructions that, when executed by the one or more processing devices, cause the one or more processing devices to perform operations including: requesting a sounding reference signal (SRS) or a channel state information (CSI) data from each of the plurality of UEs; and based on the SR from each UE, S or CSI data configures a precoder matrix, the precoder matrix allocates multiple precoded CSI reference signal (CSI-RS) resources for each UE; schedules the precoded CSI-RS resources for each UE in the multiple UEs; receives a CQI report based on the precoded CSI-RS resources received by the corresponding UE from each UE in the multiple UEs; generates a CQI matrix according to the CQI report of each UE in the multiple UEs; selects a UE subset from the multiple UEs based on the CQI matrix; and schedules DL resources for the UE subset, the DL resources including reference signals.

[0112] Embodiment 2 includes a base station according to embodiment 1 or any other embodiment of the present invention, wherein selecting the UE subset from the multiple UEs includes: generating a subset CQI matrix for each potential subset of the multiple potential subsets of the UEs among the multiple UEs; applying a reward function to at least one subset CQI matrix; based on applying the reward function, obtaining a reward value for the at least one subset CQI matrix; comparing the reward value with a threshold; and when the reward value meets the threshold, selecting the potential UE subset corresponding to the at least one subset CQI matrix as the UE subset.

[0113] Embodiment 3 includes a base station according to embodiments 1 to 2 or any other embodiment of the present invention, wherein applying the reward function includes: comparing the values ​​of the diagonal elements of the at least one subset CQI matrix with the values ​​of the non-diagonal elements of the at least one subset CQI matrix, wherein when the value of the diagonal element is relatively larger than the value of the non-diagonal element, the reward value is larger.

[0114] Embodiment 4 includes a base station according to embodiments 1 to 3 or any other embodiment of the present invention, wherein selecting the UE subset from the multiple UEs includes: generating a subset CQI matrix for each potential subset of the UEs among the multiple UEs; applying a reward function to each subset CQI matrix corresponding to each potential UE subset; obtaining a corresponding reward value for each subset CQI matrix; ranking each subset CQI matrix based on the corresponding reward value; and selecting the potential UE subset corresponding to the subset CQI matrix having a higher reward value than one or more other subset CQI matrices as the UE subset based on the ranking.

[0115] Embodiment 5 includes a base station according to embodiments 1 to 4 or any other embodiment of the present invention, wherein the operation further includes: receiving an additional CQI report based on the scheduled DL resources for the UE from at least one UE among the multiple UEs; updating the CQI matrix based on the additional CQI report; and updating the precoder matrix for one or more UEs among the multiple UEs, wherein the one or more UEs include the at least one UE.

[0116] Embodiment 6 includes a base station according to embodiments 1 to 5 or any other embodiment of the present invention, wherein the operation further includes: receiving an additional CQI report based on the scheduled DL resources for the UE from at least one UE among the multiple UEs; updating the CQI matrix based on the additional CQI report; and updating at least one reference symbol of the CSI-RS for one or more UEs among the multiple UEs.

[0117] Embodiment 7 includes a base station according to embodiments 1 to 6 or any other embodiment of the present invention, wherein the operation further includes: generating a second CQI matrix for the UE subset, wherein the DL resources are scheduled based on one or more values ​​of the second CQI matrix.

[0118] Embodiment 8 includes the base station according to embodiment 1 to 7 or any other embodiment herein, wherein the one or more values ​​of the second CQI matrix include a diagonal of the CQI matrix.

[0119] Embodiment 9 includes a base station according to embodiments 1 to 8 or any other embodiment of the present invention, wherein the operation also includes: generating a differential CQI matrix, wherein the differential CQI matrix uses four bits for each diagonal element of the differential CQI matrix and two bits for each non-diagonal element of the differential CQI matrix, wherein the differential CQI matrix includes the difference between the first CQI of the diagonal elements of the CQI matrix and the second CQI of the non-diagonal elements of the CQI matrix; and scheduling the DL resources, selecting the UE subset, or updating the precoder matrix based on the differential CQI matrix.

[0120] Embodiment 10 includes a base station according to embodiments 1 to 9 or any other embodiment herein, wherein the CQI report includes a number of CQI values ​​corresponding to the number of UEs in the plurality of UEs.

[0121] Embodiment 11 includes a base station according to embodiments 1 to 10 or any other embodiment of the present invention, wherein the precoded CSI-RS resources for each UE include CSI-RS resources for time-frequency resources allocated to the multiple UEs for MU-MIMO operation.

[0122] Embodiment 12 includes a base station according to embodiments 1 to 11 or any other embodiment of the present invention, wherein the operation further includes: updating the precoder matrix by performing the following operations: monitoring the diagonal elements and non-diagonal elements of the CQI matrix based on the periodic CSI-RS resources sent to the UE subset; when the difference between the diagonal elements and the non-diagonal elements of the CQI matrix exceeds a threshold, updating the precoder matrix using zero forcing optimization; and when the difference between the diagonal elements and the non-diagonal elements of the CQI matrix does not exceed the threshold, updating the precoder matrix using linear minimum mean square error (MMSE) optimization.

[0123] Embodiment 13 includes a base station according to embodiments 1 to 12 or any other embodiment of the present invention, wherein the operation further includes: updating the precoder matrix by performing the following operations: monitoring the diagonal elements of the CQI matrix based on the periodic CSI-RS resources sent to the UE subset; triggering an SRS or Type II CSI feedback request from the UE subset when the value of the diagonal element fails to meet a threshold value; and updating the precoder matrix based on a response to the SRS or the Type II CSI feedback request from each of the UEs.

[0124] Embodiment 14 includes a baseband processor for configuring multi-user multiple input multiple output (MU-MIMO) operations between a base station and a plurality of UEs, the baseband processor comprising: a circuit for sending data to the plurality of UEs and receiving data from the plurality of UEs; a processing device; and a memory storing instructions that, when executed by the processing device, cause the processing device to perform operations including: requesting sounding reference signal (SRS) or channel state information (CSI) data from each of the plurality of UEs; and based on the SRS or CSI data from each UE, Configure a precoder matrix that allocates multiple precoded CSI reference signal (CSI-RS) resources for each UE; schedule the precoded CSI-RS resources for each of the multiple UEs; receive a CQI report based on the precoded CSI-RS resources received by the corresponding UE from each of the multiple UEs; generate a CQI matrix based on the CQI report of each of the multiple UEs; select a UE subset from the multiple UEs based on the CQI matrix; and schedule DL resources for the UE subset, the DL resources including reference signals.

[0125] Embodiment 15 includes a baseband processor according to embodiment 14 or any other embodiment of the present invention, wherein selecting the UE subset from the multiple UEs includes: generating a subset CQI matrix for each potential subset of the multiple potential subsets of the UEs among the multiple UEs; applying a reward function to at least one subset CQI matrix; based on applying the reward function, obtaining a reward value for the at least one subset CQI matrix; comparing the reward value with a threshold; and when the reward value meets the threshold, selecting the potential UE subset corresponding to the at least one subset CQI matrix as the UE subset.

[0126] Embodiment 16 includes a baseband processor according to embodiments 14 to 15 or any other embodiment herein, wherein applying the reward function includes comparing the values ​​of the diagonal elements of the at least one subset CQI matrix with the values ​​of the non-diagonal elements of the at least one subset CQI matrix, wherein the reward value is greater when the value of the diagonal element is relatively greater than the value of the non-diagonal element.

[0127] Embodiment 17 includes a baseband processor according to embodiments 14 to 16 or any other embodiment of the present invention, wherein selecting the UE subset from the multiple UEs includes: generating a subset CQI matrix for each potential subset of the UEs among the multiple UEs; applying a reward function to each subset CQI matrix corresponding to each potential UE subset; obtaining a corresponding reward value for each subset CQI matrix; arranging each subset CQI matrix based on the corresponding reward value; and selecting the potential UE subset corresponding to the subset CQI matrix having a higher reward value than one or more other subset CQI matrices as the UE subset based on the arrangement.

[0128] Embodiment 18 includes a baseband processor according to embodiments 14 to 17, wherein the operation further includes: receiving an additional CQI report based on the scheduled DL resources for the UE from at least one UE among the multiple UEs; updating the CQI matrix based on the additional CQI report; and updating the precoder matrix for one or more UEs among the multiple UEs, wherein the one or more UEs include the at least one UE.

[0129] Embodiment 19 includes a baseband processor according to embodiments 14 to 18, wherein the operation further includes: receiving an additional CQI report based on the scheduled DL resources for the UE from at least one UE among the multiple UEs; updating the CQI matrix based on the additional CQI report; and updating at least one reference symbol of the CSI-RS for one or more UEs among the multiple UEs.

[0130] Embodiment 20 includes the baseband processor of embodiments 14 to 19, the operation further comprising generating a second CQI matrix for the UE subset, wherein the DL resources are scheduled based on one or more values ​​of the second CQI matrix.

[0131] Embodiment 21 may include a signal as described or related to any one of Embodiments 1 to 52, or a portion or component thereof.

[0132] Embodiment 22 may include a datagram, information element, packet, frame, segment, PDU or message, or a portion or component thereof, as described or associated with any one of Embodiments 1 to 20, or otherwise described in the present disclosure.

[0133] Embodiment 23 may include a signal encoded with data as described or associated with any one of Embodiments 1 to 20, or a portion or component thereof, or as otherwise described in this disclosure.

[0134] Embodiment 24 may include a signal encoded with a datagram, IE, packet, frame, segment, PDU or message as described or associated with any one of Embodiments 1 to 20, or a portion or component thereof, or otherwise described in the present disclosure.

[0135] Embodiment 25 may include an electromagnetic signal carrying computer-readable instructions, wherein execution of the computer-readable instructions by one or more processors will cause the one or more processors to perform a method, technique, or process, or portion thereof, as described or related to any one of Embodiments 1 to 24.

[0136] Embodiment 26 may include a computer program comprising instructions, wherein execution of the program by a processing element causes the processing element to perform a method, technique, or process, or a portion thereof, as described or related to any one of Embodiments 1 to 52.

[0137] Embodiment 27 may include signals in a wireless network as shown and described herein.

[0138] Embodiment 28 may include a method of communicating in a wireless network as shown and described herein.

[0139] Embodiment 29 may include a system for providing wireless communications as shown and described herein.

[0140] Embodiment 30 may include an apparatus for providing wireless communications as shown and described herein.

[0141] It is understood that the use of personally identifiable information should be subject to privacy policies and practices that are generally recognized to meet or exceed industry or government requirements for maintaining user privacy. Specifically, personally identifiable information data should be managed and processed to minimize the risk of unintentional or unauthorized access or use, and the nature of the authorized use should be clearly stated to users.

[0142] The specific implementation of the subject matter and functional operations described in this specification may be implemented in digital electronic circuits, in tangibly embodied computer software or firmware, in computer hardware (including the structures disclosed in this specification and their structural equivalents), or in a combination of one or more of them. The software specific implementation of the subject matter may be implemented as one or more computer programs. Each computer program may include one or more modules of computer program instructions encoded on a tangible non-transient computer-readable computer storage medium for data processing devices to execute or control the operation of the data processing device. Alternatively or additionally, the program instructions may be encoded in / on artificially generated propagation signals. In one example, the signal may be a machine-generated electrical signal, optical signal, or electromagnetic signal, which is generated to encode information for transmission to a suitable receiver device for execution by a data processing device. The computer storage medium may be a combination of a machine-readable storage device, a machine-readable storage substrate, a random or serial access memory device, or a computer storage medium.

[0143] The terms "data processing apparatus", "computer" and "computing device" (or equivalent forms as understood by those of ordinary skill in the art) refer to data processing hardware. For example, a data processing apparatus may encompass various apparatuses, devices and machines for processing data, including, for example, a programmable processor, a computer, or multiple processors or computers. The apparatus may also include a dedicated logic circuit, which includes, for example, a central processing unit (CPU), a field programmable gate array (FPGA) or an application-specific integrated circuit (ASIC). In some specific implementations, a data processing apparatus or a dedicated logic circuit (or a combination of a data processing apparatus or a dedicated logic circuit) may be based on hardware or software (or a combination of hardware and software). The apparatus may optionally include code that creates an execution environment for a computer program, such as code that constitutes a processor firmware, a protocol stack, a database management system, an operating system, or a combination of execution environments. The present disclosure contemplates the use of a data processing apparatus with or without a conventional operating system (e.g., LINUX, UNIX, WINDOWS, MAC OS, ANDROID or IOS).

[0144] A computer program, which may also be referred to or described as a program, software, software application, module, software module, script or code, may be written in any form of programming language. Programming languages ​​may include, for example, compiled languages, interpreted languages, declarative languages ​​or procedural languages. The program may be deployed in any form, including as a stand-alone program, module, component, subroutine or unit for use in a computing environment. A computer program may, but need not, correspond to a file in a file system. A program may be stored in a portion of a file that stores other programs or data (e.g., one or more scripts stored in a markup language document), in a single file dedicated to the program in question, or in multiple coordination files that store one or more modules, subroutines or code portions. A computer program may be deployed to execute on a computer or on multiple computers located at, for example, one site or distributed at multiple sites interconnected by a communication network. Although portions of the program shown in various figures may be shown as separate modules that implement various features and functions through various objects, methods or processes, the program may alternatively include multiple submodules, third-party services, components and libraries. On the contrary, the features and functions of various components may be combined into a single component as appropriate. The threshold for performing computational determination may be determined statically, dynamically, or both statically and dynamically.

[0145] Although this specification contains many specific implementation details, these details should not be construed as limitations on the scope of what is claimed, but rather should be viewed as descriptions of features that may be peculiar to a particular implementation. Certain features described in this specification in the context of different implementations may also be implemented in combination in a single implementation. Conversely, various features described in the context of a single implementation may also be implemented in multiple implementations individually or in any suitable sub-combination. In addition, although the previously described features may be described as functioning in certain combinations and even initially claimed as such, one or more features in a claimed combination may be removed from the combination in some cases, and a claimed combination may involve a sub-combination or a variation of a sub-combination.

[0146] Specific implementations of the subject matter have been described. Other implementations, modifications, and permutations of the implementations are within the scope of the following claims and will be apparent to those skilled in the art. Although operations are shown in a particular order in the drawings or claims, this should not be construed as requiring that such operations be performed in the particular order shown or in a sequential order, or that all of the operations shown (some operations may be considered optional) be performed to achieve the desired results. In some cases, multitasking or parallel processing (or a combination of multitasking and parallel processing) may be advantageous and may be performed as appropriate.

[0147] In addition, the division or integration of various system modules and components in the previously described specific implementations should not be understood as requiring such division or integration in all specific implementations, and it should be understood that the program components and systems can generally be integrated together in a single software product or packaged into multiple software products.

[0148] Therefore, the exemplary embodiments described above do not limit or restrict the present disclosure. Other changes, substitutions and modifications are also possible without departing from the spirit and scope of the present disclosure.

Claims

1. A base station, the base station being used to configure a multi-user multiple-input multiple-output (MU-MIMO) operation between the base station and a plurality of UEs, the base station include: A circuit configured to send data to the plurality of UEs and receive data from the plurality of UEs; one or more processing devices; and A memory storing instructions that, when executed by the one or more processing devices, cause the one or more processing devices to perform operations including: requesting a sounding reference signal (SRS) or channel state information (CSI) data from each of the plurality of UEs; configuring a precoder matrix based on the SRS or CSI data from each UE, the precoder matrix allocating a plurality of precoded CSI reference signal resources, i.e., precoded CSI-RS resources, for each UE; Scheduling the precoded CSI-RS resource for each UE among the multiple UEs; receiving, from each UE of the plurality of UEs, a channel quality indicator (CQI) report based on the precoded CSI-RS resource received by the UE; generating a CQI matrix from the CQI report for each of the plurality of UEs; selecting a subset of UEs from the plurality of UEs based on the CQI matrix; generating a second CQI matrix for the subset of UEs; as well as DL resources for the subset of UEs are scheduled based on one or more values ​​of the second CQI matrix, the DL resources comprising reference signals.

2. The base station of claim 1, wherein the subset of UEs is selected from the plurality of UEs include: generating a subset CQI matrix for each potential subset of the UEs in the plurality of UEs; applying a reward function to at least one subset CQI matrix; Based on applying the reward function, obtaining a reward value for the at least one subset CQI matrix; comparing the reward value to a threshold; as well as When the reward value satisfies the threshold, the potential subset of UEs corresponding to the at least one subset CQI matrix is ​​selected as the subset of UEs.

3. A base station according to claim 2, wherein applying the reward function includes comparing the values ​​of the diagonal elements of the at least one subset CQI matrix with the values ​​of the non-diagonal elements of the at least one subset CQI matrix, wherein the reward value is greater when the value of the diagonal element is relatively greater than the value of the non-diagonal element.

4. The base station of claim 1 , wherein the subset of UEs is selected from the plurality of UEs include: generating a subset CQI matrix for each potential subset of the UEs in the plurality of UEs; Applying a reward function to each subset CQI matrix corresponding to each potential subset of UEs; Obtain a corresponding reward value for each subset CQI matrix; arranging each subset CQI matrix based on the corresponding reward value; as well as The potential subset of UEs is selected as the subset of UEs based on the ranking, the potential subset of UEs corresponding to a subset CQI matrix having a higher reward value than one or more other subset CQI matrices.

5. The base station according to claim 1, wherein the operation further comprises: include: receiving, from at least one UE of the plurality of UEs, an additional CQI report based on scheduled DL resources for the UE; updating the CQI matrix based on the additional CQI report; as well as The precoder matrix is ​​updated for one or more UEs of the plurality of UEs, wherein the one or more UEs include the at least one UE.

6. The base station according to claim 1, wherein the operation further comprises: include: receiving, from at least one UE of the plurality of UEs, an additional CQI report based on scheduled DL resources for the UE; updating the CQI matrix based on the additional CQI report; as well as At least one reference symbol of the CSI-RS is updated for one or more of the plurality of the UEs.

7. The base station of claim 1, wherein the one or more values ​​of the second CQI matrix comprise a diagonal of the CQI matrix.

8. The base station according to claim 1, wherein the operation further comprises: include: generating a differential CQI matrix using four bits for each diagonal element of the differential CQI matrix and two bits for each off-diagonal element of the differential CQI matrix, the differential CQI matrix comprising differences between first CQIs for the diagonal elements of the CQI matrix and second CQIs for the off-diagonal elements of the CQI matrix; as well as Scheduling the DL resources, selecting the subset of UEs, or updating the precoder matrix is ​​based on the differential CQI matrix. 9 . The base station of claim 1 , wherein the CQI report comprises a number of CQI values ​​corresponding to the number of UEs in the plurality of UEs.

10. The base station of claim 1, wherein the precoded CSI-RS resources for each UE include CSI-RS resources for time-frequency resources allocated for MU-MIMO operation for the plurality of UEs.

11. The base station of claim 1 , the operations further comprising updating the precoder matrix by performing operations comprising: monitoring diagonal elements and off-diagonal elements of the CQI matrix based on the periodic CSI-RS resources sent to the subset of UEs; When the difference between the diagonal elements and the off-diagonal elements of the CQI matrix exceeds a threshold, updating the precoder matrix using zero forcing optimization; as well as When the difference between the diagonal elements and the off-diagonal elements of the CQI matrix does not exceed the threshold, The precoder matrix is ​​updated using a linear minimum mean square error (MMSE) optimization.

12. The base station of claim 1, the operations further comprising updating the precoder matrix by performing operations comprising: monitoring diagonal elements of the CQI matrix based on the periodic CSI-RS resources sent to the subset of UEs; When the value of the diagonal element fails to meet a threshold value, triggering an SRS or Type II CSI feedback request from the subset of UEs; as well as The precoder matrix is ​​updated based on a response from each of the UEs to the SRS or the Type II CSI feedback request.

13. A baseband processor for configuring a multi-user multiple input multiple output MU-MIMO operation between a base station and a plurality of UEs, the baseband processor include: A circuit configured to send data to the plurality of UEs and receive data from the plurality of UEs; Processing equipment; and A memory storing instructions that, when executed by the processing device, cause the processing device to perform operations including: requesting a sounding reference signal (SRS) or channel state information (CSI) data from each of the plurality of UEs; configuring a precoder matrix based on the SRS or CSI data from each UE, the precoder matrix allocating a plurality of precoded CSI reference signal resources, i.e., precoded CSI-RS resources, for each UE; Scheduling the precoded CSI-RS resource for each UE among the multiple UEs; receiving, from each UE of the plurality of UEs, a channel quality indicator (CQI) report based on the precoded CSI-RS resource received by the UE; generating a CQI matrix from the CQI report for each of the plurality of UEs; selecting a subset of UEs from the plurality of UEs based on the CQI matrix; generating a second CQI matrix for the subset of UEs; as well as DL resources for the subset of UEs are scheduled based on one or more values ​​of the second CQI matrix, the DL resources comprising reference signals.

14. The baseband processor of claim 13, wherein the subset of UEs is selected from the plurality of UEs include: generating a subset CQI matrix for each potential subset of the UEs in the plurality of UEs; applying a reward function to at least one subset CQI matrix; Based on applying the reward function, obtaining a reward value for the at least one subset CQI matrix; comparing the reward value to a threshold; as well as When the reward value satisfies the threshold, the potential subset of UEs corresponding to the at least one subset CQI matrix is ​​selected as the subset of UEs.

15. A baseband processor according to claim 14, wherein applying the reward function includes comparing the values ​​of the diagonal elements of the at least one subset CQI matrix with the values ​​of the non-diagonal elements of the at least one subset CQI matrix, wherein the reward value is greater when the value of the diagonal element is relatively greater than the value of the non-diagonal element.

16. The baseband processor of claim 13, wherein the subset of UEs is selected from the plurality of UEs include: generating a subset CQI matrix for each potential subset of the UEs in the plurality of UEs; Applying a reward function to each subset CQI matrix corresponding to each potential subset of UEs; Obtain a corresponding reward value for each subset CQI matrix; arranging each subset CQI matrix based on the corresponding reward value; as well as The potential subset of UEs is selected as the subset of UEs based on the ranking, the potential subset of UEs corresponding to a subset CQI matrix having a higher reward value than one or more other subset CQI matrices.

17. The baseband processor according to claim 13, wherein the operation further comprises: include: receiving, from at least one UE of the plurality of UEs, an additional CQI report based on scheduled DL resources for the UE; updating the CQI matrix based on the additional CQI report; as well as The precoder matrix is ​​updated for one or more UEs of the plurality of UEs, wherein the one or more UEs include the at least one UE.

18. The baseband processor of claim 13, wherein the operation further comprises: include: receiving, from at least one UE of the plurality of UEs, an additional CQI report based on scheduled DL resources for the UE; updating the CQI matrix based on the additional CQI report; as well as At least one reference symbol of the CSI-RS is updated for one or more of the plurality of the UEs.

19. A method for configuring a multi-user multiple input multiple output (MU-MIMO) operation between a base station and a plurality of UEs, the method include: requesting a sounding reference signal (SRS) or channel state information (CSI) data from each of the plurality of UEs; configuring a precoder matrix based on the SRS or CSI data from each UE, the precoder matrix allocating a plurality of precoded CSI reference signal resources, i.e., precoded CSI-RS resources, for each UE; Scheduling the precoded CSI-RS resource for each UE among the multiple UEs; receiving, from each UE of the plurality of UEs, a channel quality indicator (CQI) report based on the precoded CSI-RS resource received by the UE; generating a CQI matrix from the CQI report for each of the plurality of UEs; selecting a subset of UEs from the plurality of UEs based on the CQI matrix; generating a second CQI matrix for the subset of UEs; as well as DL resources for the subset of UEs are scheduled based on one or more values ​​of the second CQI matrix, the DL resources comprising reference signals.

20. The method of claim 19, wherein the subset of UEs is selected from the plurality of UEs include: generating a subset CQI matrix for each potential subset of the UEs in the plurality of UEs; applying a reward function to at least one subset CQI matrix; Based on applying the reward function, obtaining a reward value for the at least one subset CQI matrix; comparing the reward value to a threshold; as well as When the reward value satisfies the threshold, the potential subset of UEs corresponding to the at least one subset CQI matrix is ​​selected as the subset of UEs.

21. The method of claim 20, wherein applying the reward function comprises comparing values ​​of diagonal elements of the at least one subset CQI matrix with values ​​of off-diagonal elements of the at least one subset CQI matrix, wherein the reward value is greater when the values ​​of the diagonal elements are relatively greater than the values ​​of the off-diagonal elements.

22. The method of claim 19, wherein the subset of UEs is selected from the plurality of UEs include: generating a subset CQI matrix for each potential subset of the UEs in the plurality of UEs; Applying a reward function to each subset CQI matrix corresponding to each potential subset of UEs; Obtain a corresponding reward value for each subset CQI matrix; arranging each subset CQI matrix based on the corresponding reward value; as well as The potential subset of UEs is selected as the subset of UEs based on the ranking, the potential subset of UEs corresponding to a subset CQI matrix having a higher reward value than one or more other subset CQI matrices.

23. The method according to claim 19, further comprising: include: receiving, from at least one UE of the plurality of UEs, an additional CQI report based on scheduled DL resources for the UE; updating the CQI matrix based on the additional CQI report; as well as The precoder matrix is ​​updated for one or more UEs of the plurality of UEs, wherein the one or more UEs include the at least one UE.

24. The method according to claim 19, further comprising: include: receiving, from at least one UE of the plurality of UEs, an additional CQI report based on scheduled DL resources for the UE; updating the CQI matrix based on the additional CQI report; as well as At least one reference symbol of the CSI-RS is updated for one or more of the plurality of the UEs.

25. The method according to claim 19, further comprising: include: generating a differential CQI matrix using four bits for each diagonal element of the differential CQI matrix and two bits for each off-diagonal element of the differential CQI matrix, the differential CQI matrix comprising differences between first CQIs for the diagonal elements of the CQI matrix and second CQIs for the off-diagonal elements of the CQI matrix; as well as Scheduling the DL resources, selecting the subset of UEs, or updating the precoder matrix is ​​based on the differential CQI matrix.

26. The method of claim 19, further comprising updating the precoder matrix by performing operations comprising: monitoring diagonal elements and off-diagonal elements of the CQI matrix based on the periodic CSI-RS resources sent to the subset of UEs; When the difference between the diagonal elements and the off-diagonal elements of the CQI matrix exceeds a threshold, updating the precoder matrix using zero forcing optimization; as well as When the difference between the diagonal elements and the off-diagonal elements of the CQI matrix does not exceed the threshold, The precoder matrix is ​​updated using a linear minimum mean square error (MMSE) optimization.

27. The method of claim 19, the operations further comprising updating the precoder matrix by performing operations comprising: monitoring diagonal elements of the CQI matrix based on the periodic CSI-RS resources sent to the subset of UEs; When the value of the diagonal element fails to meet a threshold value, triggering an SRS or Type II CSI feedback request from the subset of UEs; as well as The precoder matrix is ​​updated based on a response from each of the UEs to the SRS or the Type II CSI feedback request.

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