System and method for channel sounding and channel state information feedback for distributed multiple-input multiple-output precoding

Abstract

Systems and methods for channel sounding and channel state information (CSI) feedback for distributed multiple-input multiple-output (MIMO) precoding are provided. A first wireless communication device of the plurality of wireless communication devices may transmit a first reference signal to a wireless communication node. The first wireless communication device may receive a second reference signal from the wireless communication node. A first wireless communication device may send a report to a wireless communication node that includes signaling indicating channel correlation information associated with a plurality of wireless communication devices.

Description

Technical Field

[0001] The present disclosure relates generally to wireless communications, including but not limited to systems and methods for channel sounding and channel state information (CSI) feedback for distributed multiple input / multiple output (MIMO) precoding. Background Art

[0002] Currently, the Third Generation Partnership Project (3GPP), a standards organization, is developing a new radio interface called 5G New Radio (5G NR) and the Next Generation Packet Core Network (NG-CN or NGC). 5G NR will have three main components: the 5G Access Network (5G-AN), the 5G Core Network (5G GC), and the User Equipment (UE). To facilitate the implementation of diverse data services and requirements, the various elements of the 5GC (also known as network functions) have been simplified, with some being software-based and others hardware-based, allowing for adaptation as needed. Summary of the Invention

[0003] The exemplary embodiments disclosed herein are intended to solve problems associated with one or more problems existing in the prior art and to provide additional features that will become apparent when reference is made to the following detailed description in conjunction with the accompanying drawings. According to various embodiments, exemplary systems, methods, devices, and computer program products are disclosed herein. However, it should be understood that these embodiments are presented by way of example and not limitation, and it will be apparent to those of ordinary skill in the art reading this disclosure that various modifications may be made to the disclosed embodiments while remaining within the scope of this disclosure.

[0004] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A first wireless communication device among multiple wireless communication devices (e.g., UEs) may send / transmit / provide / signal / transmit a first reference signal to a wireless communication node (e.g., a base station (BS), a distributed node, a gNB, or a transmission and reception point (TRP)). The first wireless communication device may receive / obtain / acquire / derive a second reference signal from the wireless communication node. The first wireless communication device may send a report to the wireless communication node. The report may include / contain signaling indicating / indicating channel correlation information associated with the multiple wireless communication devices.

[0005] In some implementations, the first reference signal may include a sounding reference signal (SRS). In some implementations, the second reference signal may include a precoded channel state information reference signal (CSI-RS).

[0006] In some implementations, the channel correlation information may include a matrix having dimensions. In some implementations, at least one of the dimensions may be determined based on the number of the plurality of wireless communication devices. In some implementations, at least one of the dimensions may be related to the number of antennas, the number of streams, or the number of panels of any one of the plurality of wireless communication devices. In some implementations, at least one of the dimensions may be determined based on a number configured by the wireless communication node for the first wireless communication device.

[0007] In some implementations, the matrix may be composed of multiple codebook vectors. In some embodiments, the matrix may be composed of multiple quantization vectors. In some implementations, the signaling may include / contain multiple indices that map to a basis for representing the channel correlation information. In some implementations, the signaling may include multiple parameters for quantizing the channel correlation information.

[0008] At least one aspect relates to a system, method, apparatus, or computer-readable medium. A wireless communication node (e.g., a base station) may receive a first reference signal from each of a plurality of wireless communication devices (e.g., a user equipment terminal). The wireless communication node may transmit a second reference signal to at least a first one of the plurality of wireless communication devices. The wireless communication node may receive a report from the first wireless communication device. The report may include signaling indicating channel correlation information associated with the plurality of wireless communication devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Various exemplary embodiments of the present solution are described in detail below with reference to the following diagrams or drawings. The drawings are provided for illustrative purposes only and depict only exemplary embodiments of the present solution to facilitate the reader's understanding of the present solution. Therefore, the drawings should not be construed as limiting the breadth, scope, or applicability of the present solution. It should be noted that for clarity and ease of illustration, the drawings are not necessarily drawn to scale.

[0010] Figure 1 shows an exemplary cellular communication network in which the techniques disclosed herein may be implemented according to embodiments of the present disclosure;

[0011] Figure 2 A block diagram illustrating an exemplary base station and user terminal equipment according to some embodiments of the present disclosure is shown;

[0012] Figure 3 An example of a distributed massive Multiple Input Multiple Output (MIMO) network according to some embodiments of the present disclosure is shown;

[0013] Figure 4 An exemplary flow chart of a channel information acquisition process according to some embodiments of the present disclosure is shown;

[0014] Figure 5 shows an exemplary grid of time-frequency domain resource elements according to some embodiments of the present disclosure;

[0015] Figure 6 illustrates exemplary operations using Hadamard products according to some embodiments of the present disclosure; and

[0016] Figure 7 A flowchart of an exemplary method for channel sounding and channel state information (CSI) feedback for distributed MIMO precoding according to an embodiment of the present disclosure is shown. DETAILED DESCRIPTION

[0017] 1. Mobile Communication Technology and Environment

[0018] Figure 1An exemplary wireless communication network and / or system 100 is shown in which the techniques disclosed herein may be implemented in accordance with an embodiment of the present disclosure. In the following discussion, the wireless communication network 100 may be any wireless network, such as a cellular network or a narrowband Internet of Things (NB-IoT) network, and is referred to herein as "network 100". This exemplary network 100 includes a base station 102 (hereinafter referred to as "BS 102"; also referred to as a wireless communication node) and a user terminal device 104 (hereinafter referred to as "UE 104"; also referred to as a wireless communication device), which may communicate with each other via a communication link 110 (e.g., a wireless communication channel), and also includes cell clusters 126, 130, 132, 134, 136, 138, and 140 covering a geographic area 101. In Figure 1 1 , BS 102 and UE 104 are within the respective geographic boundaries of cell 126. Each of the other cells 130, 132, 134, 136, 138, and 140 may include at least one base station operating within its allocated bandwidth to provide adequate wireless coverage for its intended users.

[0019] For example, BS 102 may operate under an allocated channel transmission bandwidth to provide sufficient coverage to UE 104. BS 102 and UE 104 may communicate via downlink radio frames 118 and uplink radio frames 124, respectively. Each radio frame 118 / 124 may be further divided into subframes 120 / 127, which may contain data symbols 122 / 128. In the present disclosure, BS 102 and UE 104 are described as non-limiting examples of "communication nodes," which may generally implement the methods disclosed herein. Depending on various implementations of the present solution, these communication nodes may be capable of wireless and / or wired communication.

[0020] Figure 2 A block diagram of an exemplary wireless communication system 200 for transmitting and receiving wireless communication signals (e.g., OFDM / OFDMA signals) according to some embodiments of the present solution is shown. The system 200 may include components and elements configured to support known or conventional operating functions, which need not be described in detail herein. In an exemplary embodiment, the system 200 may be used in a wireless communication environment (e.g., Figure 1 The wireless communication environment 100 of FIG. 1 may be used to communicate (eg, transmit and receive) data symbols, as described above.

[0021] System 200 generally includes a base station 202 (hereinafter referred to as "BS 202") and a user terminal device 204 (hereinafter referred to as "UE 204"). BS 202 includes a BS (base station) transceiver module 210, a BS antenna 212, a BS processor module 214, a BS memory module 216, and a network communication module 218, each of which is coupled and interconnected as needed via a data communication bus 220. UE 204 includes a UE (user equipment) transceiver module 230, a UE antenna 232, a UE memory module 234, and a UE processor module 236, each of which is coupled and interconnected as needed via a data communication bus 240. BS 202 communicates with UE 204 via a communication channel 250, which can be any wireless channel or other medium suitable for data transmission as described herein.

[0022] As will be understood by those skilled in the art, the system 200 may also include Figure 2 . It will be understood by those skilled in the art that the various exemplary blocks, modules, circuits, and processing logic described in conjunction with the embodiments disclosed herein can be implemented in hardware, computer-readable software, firmware, or any practical combination thereof. In order to clearly illustrate this interchangeability and compatibility of hardware, firmware, and software, various exemplary components, blocks, modules, circuits, and steps are generally described in terms of their functionality. Whether such functionality is implemented as hardware, firmware, or software may depend on the specific application and the design constraints imposed on the overall system. A person skilled in the art who is familiar with the concepts described herein can implement such functionality in an appropriate manner for each specific application, but such implementation decisions should not be construed as limiting the scope of this disclosure.

[0023] According to some embodiments, the UE transceiver 230, which may be referred to herein as an "uplink" transceiver 230, includes a radio frequency (RF) transmitter and an RF receiver, both of which include circuitry coupled to an antenna 232. A duplex switch (not shown) may alternatively couple the uplink transmitter or receiver to the uplink antenna in a time-division duplex manner. Similarly, according to some embodiments, the BS transceiver 210, which may be referred to herein as a "downlink" transceiver 210, includes an RF transmitter and an RF receiver, both of which include circuitry coupled to an antenna 212. A downlink duplex switch may alternatively couple the downlink transmitter or receiver to the downlink antenna 212 in a time-division duplex manner. The operation of the two transceiver modules 210 and 230 may be coordinated in time such that the downlink transmitter is coupled to the downlink antenna 212 while the uplink receive circuitry is coupled to the uplink antenna 232 to receive transmissions on the wireless transmit link 250. Instead, the operations of the two transceivers 210 and 230 may be coordinated in time such that the uplink transmitter is coupled to the uplink antenna 232 while the downlink receiver is coupled to the downlink antenna 212 to receive transmissions on the wireless transmission link 250. In some embodiments, there is tight time synchronization with minimal guard time between duplex direction switches.

[0024] The UE transceiver 230 and the base station transceiver 210 are configured to communicate via a wireless data communication link 250 and are used in conjunction with an appropriately configured RF antenna arrangement 212 / 232 that can support specific wireless communication protocols and modulation schemes. In some exemplary embodiments, the UE transceiver 210 and the base station transceiver 210 are configured to support industry standards such as Long Term Evolution (LTE) and emerging 5G standards. However, it should be understood that the present disclosure is not necessarily limited to application to a particular standard and related protocols. Instead, the UE transceiver 230 and the base station transceiver 210 can be configured to support alternative or additional wireless data communication protocols, including future standards or variations thereof.

[0025] According to various embodiments, BS 202 may be, for example, an evolved Node B (eNB), a serving eNB, a target eNB, a home base station, or a pico base station. In some embodiments, UE 204 may be embodied as various types of user equipment, such as a mobile phone, a smartphone, a personal digital assistant (PDA), a tablet computer, a laptop computer, a wearable computing device, or the like. Processor modules 214 and 236 may be implemented or embodied using a general-purpose processor, a content-addressable memory, a digital signal processor, an application-specific integrated circuit, a field programmable gate array, any suitable programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof, designed to perform the functions described herein. In this manner, a processor may be implemented as a microprocessor, a controller, a microcontroller, a state machine, or the like. A processor may also be implemented as a combination of computing devices, such as a combination of a digital signal processor and a microprocessor, a plurality of microprocessors, one or more microprocessors combined with a digital signal processor core, or any other such configuration.

[0026] Furthermore, the steps of the methods or algorithms described in conjunction with the embodiments disclosed herein may be embodied directly in hardware, firmware, or software modules executed by processor modules 214 and 236, respectively, or any practical combination thereof. Memory modules 216 and 234 may be implemented as RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, a hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. In this regard, memory modules 216 and 234 may be coupled to processor modules 210 and 230, respectively, such that processor modules 210 and 230 can read information from and write information to memory modules 216 and 234, respectively. Memory modules 216 and 234 may also be integrated into their respective processor modules 210 and 230. In some embodiments, memory modules 216 and 234 may each include a cache memory for storing temporary variables or other intermediate information during execution of instructions by processor modules 210 and 230, respectively. Memory modules 216 and 234 may also each include non-volatile memory for storing instructions to be executed by processor modules 210 and 230, respectively.

[0027] The network communication module 218 generally represents the hardware, software, firmware, processing logic and / or other components of the base station 202 that enable the base station transceiver 210 to communicate bidirectionally with other network components and communication nodes configured to communicate with the base station 202. For example, the network communication module 218 can be configured to support Internet or WiMAX services. In a typical deployment, the network communication module 218 provides an 802.3 Ethernet interface so that the base station transceiver 210 can communicate with a traditional Ethernet-based computer network, but is not limited to this scenario. In this manner, the network communication module 218 may include a physical interface for connecting to a computer network (e.g., a mobile switching center (MSC)). As used herein, the terms "configured for," "configured to," and variations thereof, with respect to a particular operation or function, refer to a device, component, circuit, structure, machine, signal, etc. that is physically constructed, programmed, formatted, and / or arranged to perform that particular operation or function.

[0028] The Open Systems Interconnection (OSI) model is a conceptual and logical layout that defines the network communication methods used by systems (e.g., wireless communication devices, wireless communication nodes) that can openly interconnect and communicate with other systems. The model is divided into seven subcomponents or layers, each of which represents a set of conceptual services provided to the layers above and below it. The OSI model also defines logical networks and effectively describes computer data packet transmission through the use of different layer protocols. The OSI model is also referred to as the seven-layer OSI model or seven-layer model. In some embodiments, the first layer may be the physical layer. In some embodiments, the second layer may be the medium access control (MAC) layer. In some embodiments, the third layer may be the radio link control (RLC) layer. In some embodiments, the fourth layer may be the packet data convergence protocol (PDCP) layer. In some embodiments, the fifth layer may be the radio resource control (RRC) layer. In some embodiments, the sixth layer may be a Non Access Stratum (NAS) layer or an Internet Protocol (IP) layer, and the seventh layer may be other layers.

[0029] Various exemplary embodiments of the present solution are described below with reference to the accompanying drawings to enable one of ordinary skill in the art to make and use the present solution. As will be apparent to one of ordinary skill in the art, after reading this disclosure, various changes or modifications may be made to the embodiments described herein without departing from the scope of the present solution. Therefore, the present solution is not limited to the exemplary embodiments and applications described and illustrated herein. In addition, the specific order or hierarchy of steps in the methods disclosed herein are merely exemplary methods. Based on design preferences, the specific order or hierarchy of steps of the disclosed methods or processes may be rearranged without departing from the scope of the present solution. Thus, one of ordinary skill in the art will understand that the methods and techniques disclosed herein present various steps or actions in a sample order, and that the present solution is not limited to the specific order or hierarchy presented, unless otherwise expressly stated.

[0030] 2. System and method for channel sounding and CSI feedback for distributed MIMO precoding

[0031] refer to Figure 3 , an embodiment of a distributed massive multiple-input / multiple-output (MIMO) network 300 is shown. In certain environments, distributed massive MIMO (e.g., sometimes referred to as or known as advanced MIMO technology) may be introduced / discussed / utilized to provide ubiquitous data services (or form related visions) to individual access users (e.g., UE 104 or wireless communication devices). Compared with certain distributed MIMO technologies (e.g., standard distributed MIMO technologies), distributed massive MIMO is expected to frequently provide a relatively larger / larger / higher amount of macro-diversity gain by flexibly programming electromagnetic signal propagation, and this gain may be constructed / formed in a manner based on channel precoding (e.g., coherent) transmission at the physical layer. A series (or a certain number) of channel precoding schemes / methods / approaches / configurations based on local channel state information can be designed or provided to support coherent transmission of distributed massive MIMO.

[0032] However, in multi-user scenarios / situations / environments, most applied channel precoding schemes may suffer / induce or cause performance loss, for example, performance loss caused by residual cross interference. In some distributed large-scale MIMO systems / environments, in order to successfully perform channel precoding without generating cross interference, a certain amount / a certain number of local channel state information (CSI) exchanges (e.g., sometimes referred to as channel information exchange (CIE)) may need to be performed between distributed nodes / local nodes / base stations 102 / access points (APs). For example, distributed precoding in a distributed large-scale MIMO environment may involve the acquisition of complete channel information (e.g., the amount of channel state information), which may cause or result in a relatively heavy communication overhead / load for implementing CIE between BS102 / distributed nodes. In addition, due to various requirements for latency and communication overhead, the ideal channel state information (CSI) exchange strategy may be at least partially prohibited, blocked or restricted. Therefore, the system and method of the technical solution can provide the techniques, features and / or operations discussed herein to reduce the amount of CIE for distributed large-scale MIMO.

[0033] refer to Figure 4 , an exemplary flow chart 400 of a channel information acquisition process is shown. Flow chart 400 may include features, operations, or processes performed by BS 102 (e.g., a distributed node, gNB, TRP, local node, or AP) and UE 104. BS 102 may communicate with UE 104 (and other UEs 104) to exchange / transmit / provide information or data. In general, BS 102 may receive a sounding signal from UE 104. BS 102 may send a sounding signal to UE 104. BS 102 may receive feedback from UE 104. For example, BS 102 and UE 104 may perform the features discussed herein to reduce the amount of CIE in / with the distributed massive MIMO network 300.

[0034] Example steps for UL sounding signal

[0035] In various implementations, UE 104 may transmit / send / provide / transmit a sounding signal (e.g., an uplink (UL) sounding signal or a first sounding signal) to BS 102 / distributed node. BS 102 may receive / obtain / acquire / obtain the sounding signal from UE 104. In some implementations discussed herein, a signal (or at least a portion of a signal containing a pilot) sent by BS 102 and / or UE 104 that includes / contains a pilot for channel estimation may be referred to as a reference signal or training symbol. In some cases, the UL sounding signal may be referred to or referenced as a Sounding Reference Signal (SRS), which is a specific class of reference signal / training symbol. In some configurations, the UL sounding signal may include at least one pilot. The pilots discussed in this disclosure may correspond to or be provided as predefined signals to estimate / determine channel information between BS 102 and UE 104.

[0036] refer to Figure 5 , shows an exemplary grid 500 of time-frequency domain resource elements. In some configurations, if pilots of (UL) sounding signals (or reference signals) from various UEs 104 are transmitted over the same resource elements (e.g., time-frequency resources), UEs 104 may utilize predetermined orthogonal pilot sequences intended / used for, or configured to separate / split / partition / classify at least one received signal at base station 102 into pilot sequence components from multiple UEs 104. In some arrangements, if the inner product between pilot sequences composed of real / complex numbers is zero, each pilot sequence may be referred to as an orthogonal pilot sequence. Otherwise, each such pilot sequence may be referred to as a non-orthogonal pilot sequence. In some arrangements, the pilot sequences transmitted by a particular UE 104 may be referred to as pilot sequence components. In some cases, UEs 104 may utilize predetermined non-orthogonal pilot sequences, for example, if / when the pilots carried in the UL sounding signal occupy / are located in / on different resource elements.

[0037] Example steps for DL ​​sounding signal

[0038] After receiving the UL sounding signals from one or more UEs 104, BS 102 may process the UL sounding signals of UEs 104 to determine / identify channel response and / or perform precoding. In response to determining the channel response and / or completing precoding, BS 102 may send a DL sounding signal (e.g., sometimes referred to as a second sounding signal) with a precoded pilot to UE 104 (and other UEs 104).

[0039] In some cases, the DL sounding signal may correspond to or include a CSI reference signal (CSI-RS), which may be another category of reference signal / training symbol. In some configurations, the pilot may be integrated into the CSI-RS. In some configurations, the pilot may be integrated into one or more training symbols. In some cases, the precoded pilot may be referred to as a precoded CSI-RS / training symbol. Each / independent BS 102 / distributed node (e.g., labeled m) may transmit / send / provide an original / initial UL pilot sequence based on the original / initial UL pilot sequence. and received / acquired pilot sequence Estimate / determine the channel response of UE 104 (e.g., labeled k) For example, BS 102 may use the following formula / function to determine the channel response:

[0040]

[0041] In formula (1), the labeled f may represent or indicate a function designed / configured / set for channel estimation (e.g., channel information estimation). In some cases, if the pilots of the UL sounding signal are transmitted on two or more layers, the BS 102 may (or is expected to) separate the received pilots (of the UL sounding signal from the UE 104) into multiple / different components according to the layer dimension before performing channel estimation.

[0042] After or in response to separating the received pilot, BS 102'm' may perform / conduct / implement / initiate arrive For example, the transformation of the original DL pilot sequence For example, in response to the separated received pilot, BS 102 may mask / precode the original DL pilot sequence using the following formula:

[0043]

[0044] The element Φ(...) of formula (2) can represent or indicate a transformation function, wherein the element It can represent the Hadamard product or operation. In some cases, the normalization function Can be regarded as In this case, formula (2) can be updated or replaced by the following formula:

[0045]

[0046] In formula (3), the operator ‖…‖ (eg, representing modulus) may output the modulus value of the input quantity. The variable M may express, represent, or represent the total number of BSs 102 / distributed nodes.

[0047] refer to Figure 6 , illustrating exemplary operations 600 using Hadamard products. Generating masked / precoded pilot sequences The process / operation 600 may be performed by / via the use of a Hadamard product. Figure 6 In the embodiment of FIG. 5 , BS 102 may be a distributed node “1”, and The length of 1 can be 4. BS102 can be and The Hadamard product between the two is used to generate the mask / precoded pilot sequence

[0048] Example steps for feeding back CSI reports

[0049] In various implementations, the UE 104 (or other UEs 104) may receive / obtain a DL sounding signal from the BS 102. In response to receiving the DL sounding signal, the UE 104 may determine signaling (e.g., channel correlation information) indicating / reflecting the degree / level / magnitude of channel correlation between or associated with each user equipment 104. After determining the signaling indicating the channel correlation information, the UE 104 may provide / signal / transmit feedback messages / information / data to the BS 102. In some cases, the channel correlation may be represented in the form of a matrix having certain dimensions. In some configurations, the matrix may comprise dimensions K×N, where K and N may be the number of correlation coefficients selected between streams / layers of the UE 104 and the number of correlation coefficients selected between antennas / layers / streams of a particular user equipment 104, respectively. In some configurations, the matrix may comprise dimensions K×N×T, where K, N, and T may be the number of selected correlation coefficients between streams / layers of the UE 104, the number of selected correlation coefficients between antennas / layers / streams of a particular UE 104, and / or the number of time periods or basic time units, respectively. The feedback may include a channel state information (CSI) report related to or associated with signaling indicating channel correlation information.

[0050] For example, in certain environments / systems / scenarios, the pilot in the DL sounding signal may be described / presented / indicated / expressed as follows:

[0051]

[0052] Based on or according to and (e.g., using equation (4)), UE 104 (e.g., UE k ) can be obtained from the following measurement quantities / acquire the channel correlation vector :

[0053]

[0054] K′ may represent the length of the channel correlation vector, which may represent or be considered as the length of the channel correlation vector of the UE 104 (eg, UE k ) at least a portion of the feedback content of the precoding vector Φ(H). In some configurations, the values ​​of the parameters k, K', and K may be in the following order: 1 ≤ k ≤ K' ≤ K (e.g., a criterion regarding the values ​​of k, K', and K). k ) can be represented / marked as follows:

[0055]

[0056] In some implementations, the parameter K′ may be predetermined / predefined and / or signaled / provided by the BS 102 before starting / performing / executing / initiating the UL feedback procedure. In some configurations, the parameter may be configured for each UE 104 (e.g., similar between certain UEs 104 or unique between UEs 104), such that, for example, the BS 102 may dynamically adjust / update / refine the parameter to achieve effective load balancing between the UEs 104. In some scenarios, for example, the parameter K′ may be a common / shared parameter for all UEs 104, a group of UEs 104, or at least a plurality of UEs 104.

[0057] In response, UE 104 (e.g., UE k ) can be determined for / belong to UE 104 may send a replacement vector to BS 102 that matches the vector Parameters S associated with the BS 102 and / or UE 104. In various implementations, one or more types of codebooks (e.g., precoding matrix codebooks) may be introduced / provided / indicated / configured to / for the base station 102 and / or UE 104. Depending on the codebook type, the base station 102 and / or UE 104 may perform different functions / operations. In some cases, various codebook types may be predefined / preconfigured for the BS 102 and / or UE 104. In some configurations, the BS 102 may send / provide control signaling to inform the UE 104 of the codebook type to be used.

[0058] For example, if a first codebook type (eg, codebook type I, as shown in Table 1) is introduced / provided, BS 102 may select a codebook type according to its The (codeword) vector indexed by K′ and v is determined by the similarity of K′ and v. v may represent the content fed back by UE 104 to base station 102. The codeword index v may be a sub-signaling field and / or parameter included in the signaling indicating the channel correlation. In some cases, if Table 2 of the second codebook type (e.g., codebook type II) is adopted / introduced, then UE 104 (e.g., UE k ) can be parameter n=(n1…n K′) is signaled to BS 102, for example to form / construct / generate In this case, for example, the signaling indicating the channel correlation may carry / include an integer set n for the vector quantizer instead of the codeword index v.

[0059] In some implementations, when When the amplitude factor is added in the quantization process of , for example, the parameters n and c of the third codebook type (eg, codebook type III, exemplified or shown in Table 3) are (c1 ... c K′ ) can be performed by UE 104 (e.g., UE k ) is signaled / provided / transmitted to the base station 102. For example, if the number of UEs 104 (eg, users) scheduled for CSI feedback is 4, then the UE k Can be configured to calculate / calculate / determine each H k (H j ) * and / or H j (H k ) * Items / elements, as shown / provided in Table 4. The superscripts k and j may be limited or associated with the number of scheduled UEs 104 and the predetermined set, respectively. In some implementations, the index k may belong to or be included in the closed integer interval [1, 4]. In this embodiment, when feedback mode I in Table 5 is enabled, under the condition / criteria / parameter that the set index is configured as 0, the predetermined sets (e.g., {1, 2, 3, 4}, {2, 3, 4}, {3, 4}, and {4}) may be assigned to UE1, UE2, UE3, and UE4, respectively. In some cases, for example, if feedback mode II in Table 6 is enabled, the set index of each UE 104 may be flexibly / dynamically configured / adjusted / updated, with the condition / requirement that the union / combination of the predetermined sets of the four UEs 104 is complete in order to reconstruct the correlation matrix of Table 4.

[0060] In some implementations, continuing or referring to the above embodiment, if 6, 3, and 0 are assigned as set indices for UE2, UE3, and UE4, respectively, then the set index for UE1 may be 7, thereby setting or enabling the entries indexed by (k=1, j=1), (k=1, j=2), (k=1, j=3), (k=1, j=4), (k=2, j=2), (k=2, j=3), (k=2, j=4), (k=3, j=3), (k=3, j=4), and (k=4, j=4). UE 104 may provide feedback to BS 102 including the indexed entries. Based on or using the entries, BS 102 may generate / form / construct a channel correlation matrix.

[0061] In some configurations, when codebook type 1 and feedback mode 1 are used / selected, for example, if the index is set to 0, the following vector may be constructed / generated.

[0062]

[0063] In some cases, the construction of (vector) u1 may be terminated / cancelled. In response to terminating the construction of u1, UE 104 (eg, UE1, continuing the previous embodiment) may continue to search / find / identify vector u of the same dimension. v , which minimizes the following (norm) distance:

[0064] d=‖u1-u v ‖ p ,p>0

[0065] The vector u can be provided in Table 1 v As discussed in this paper, the vector u v The subscript v of may be information transmitted to BS102 / distributed nodes. Similar to the above, for example, if codebook type II and feedback mode II are selected, vectors u1 and u2 may be generated as follows: n :

[0066]

[0067] In this embodiment, the set index of feedback mode II of UE1 may be 7, and (N1, N2, N3, N4) may be predetermined. As an alternative to the norm distance, the correlation coefficient may be considered and / or used to evaluate / determine the relationship between u1 and u n The similarity level between, for example, can be expressed as follows:

[0068]

[0069] In some configurations, regardless of the metric used herein, (n1, n2, n3, n4) may be the amount delivered / transmitted / provided / sent by the UE 104 to the BS 102. In some cases, if the system (e.g., the BS 102 and / or the UE 104) supports the feedback modes discussed above, dedicated signaling from the UE 104 (and / or the BS 102) may be added to indicate which mode is enabled / selected / indicated for ongoing feedback. In various configurations, for example, other combinations of the number of UEs 104, codebook types, and / or feedback modes may be implemented using features, operations, or techniques of the technical solutions, and for simplicity, a relatively small number of embodiments are provided herein.

[0070] Table 1 Codebook Type I

[0071]

[0072]

[0073] Table 2 Codebook Type II

[0074]

[0075] Table 3 Codebook Type III

[0076]

[0077] Table 4 (Channel) Correlation Matrix

[0078]

[0079] Table 5 Feedback Mode I

[0080]

[0081]

[0082] Table 6 Feedback Mode II

[0083]

[0084] Now refer to Figure 7 , a flow chart of an exemplary method 700 for channel sounding and channel state information (CSI) feedback for distributed MIMO precoding is shown. The method 700 may be performed or implemented by one or more network elements (e.g., at least one UE 104 and at least one BS 102 / distributed node), such as in conjunction with Figure 1-6 In summary, method 700 may include, at operation 702, transmitting a first reference signal. At operation 704, method 700 may include receiving the first reference signal. At operation 706, method 700 may include transmitting a second reference signal. At operation 708, method 700 may include receiving the second reference signal. At operation 710, method 700 may include transmitting a report. At operation 712, method 700 may include receiving a report.

[0085] Still refer to Figure 7 , further detailing, in operation 702, at least one of the various wireless communication devices (e.g., a first UE among multiple UEs) may send / transmit / provide / signal / transmit a first reference signal (e.g., a sounding reference signal (SRS)) to a wireless communication node (e.g., a BS, a gNB, a TRP, a distributed node, a local node, or an access point (AP)).

[0086] At operation 704, the wireless communication node may receive / obtain a first reference signal from the wireless communication device. In various implementations, the first reference signal may include or correspond to a sounding reference signal (SRS).

[0087] At operation 706, the wireless communication node may transmit a second reference signal to the wireless communication device. At operation 708, the wireless communication device may receive the second reference signal from the wireless communication node. In various implementations, the second reference signal may include or correspond to a channel state information reference signal (CSI-RS).

[0088] At operation 710, a wireless communication device may send a report (e.g., feedback) to a wireless communication node. The report may include signaling indicating channel correlation information associated with multiple wireless communication devices (e.g., signaling reflecting channel correlation between wireless communication devices or users). At operation 712, the wireless communication node may receive the report from the wireless communication device, thereby avoiding, for example, information exchange with other wireless communication nodes (e.g., between wireless communication nodes).

[0089] In various implementations, the channel correlation information may include a matrix having dimensions (e.g., a vector). In some configurations, at least one of the dimensions of the matrix may be based on or determined according to the number of wireless communication devices, for example, to reduce / minimize feedback overhead. In some configurations, at least one of the dimensions may be related to the number of antennas, the number of streams, and / or the number of panels of any one of the wireless communication devices.

[0090] In some configurations, at least one of the dimensions may be determined based on a number (e.g., K') configured by the wireless communication node for the first wireless communication device among the other wireless communication devices. In some configurations, the matrix may be composed of / constituted from a plurality of codebook vectors (e.g., codebook type I, etc.). In some configurations, the matrix is ​​composed of / constituted from various quantization vectors (e.g., codebook type II, codebook type III, etc.).

[0091] In some configurations, the signaling may include various indices that map to bases for representing channel correlation information, for example, to reduce feedback overhead. In some configurations, the signaling may include multiple parameters for quantizing channel correlation information, such as for a tradeoff between feedback overhead and information accuracy.

[0092] Although various arrangements of the present solution have been described above, it should be understood that these arrangements are presented by way of example only and not limitation. Similarly, the various diagrams may depict an exemplary architecture or configuration, which are provided to enable those of ordinary skill in the art to understand the exemplary features and functions of the present solution. However, such persons will understand that the present solution is not limited to the exemplary architectures or configurations shown, but can be implemented using various alternative architectures and configurations. In addition, as those of ordinary skill in the art will understand, one or more features of some arrangements can be combined with one or more features of another arrangement described herein. Therefore, the breadth and scope of the present disclosure should not be limited by any of the exemplary arrangements described above.

[0093] It should also be understood that any reference to an element herein using designations such as "first," "second," etc., does not generally limit the quantity or order of those elements. Rather, these designations may be used herein as a convenient means of distinguishing between two or more elements or instances of an element. Thus, a reference to a first and a second element does not mean that only two elements may be used, or that the first element must precede the second element in some manner.

[0094] Furthermore, persons of ordinary skill in the art will appreciate that information and signals may be represented using any of a variety of different technologies and methods. For example, the data, instructions, commands, information, signals, bits, and symbols mentioned in the above description may be represented by voltage, current, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.

[0095] Those skilled in the art will further understand that any of the various exemplary logic blocks, modules, processors, means, circuits, methods, and functions described in conjunction with the various aspects disclosed herein may be implemented by electronic hardware (e.g., digital implementation, analog implementation, or a combination of the two), firmware, various forms of programs or design code containing instructions (for convenience, referred to herein as "software" or "software modules"), or any combination of these technologies. In order to clearly illustrate this interchangeability of hardware, firmware, and software, the above generally describes various exemplary components, blocks, modules, circuits, and steps from a functional perspective. Whether such functionality is implemented as hardware, firmware, or software, or a combination of these technologies, depends on the specific application and the design constraints imposed on the overall system. Those skilled in the art may implement the described functionality in various ways for each specific application, and such implementation decisions do not depart from the scope of this disclosure.

[0096] Furthermore, those skilled in the art will appreciate that the various exemplary logic blocks, modules, devices, components, and circuits described herein may be implemented within or performed by an integrated circuit (IC), which may include a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA), or other programmable logic device, or any combination thereof. The logic blocks, modules, and circuits may also include an antenna and / or a transceiver to communicate with various components within a network or within a device. A general purpose processor may be a microprocessor, but alternatively, the processor may be any conventional processor, controller, or state machine. A processor may also be implemented as a combination of computing devices, for example, a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other suitable configuration to perform the functions described herein.

[0097] If implemented in software, these functions may be stored as one or more instructions or codes on a computer-readable medium. Therefore, the steps of the method or algorithm disclosed herein may be implemented as software stored on a computer-readable medium. Computer-readable media include both computer storage media and communication media, and communication media include any medium capable of transmitting a computer program or code from one place to another. The storage medium can be any available medium that can be accessed by a computer. By way of example and not limitation, such computer-readable media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage device, or any other medium that can be used to store desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0098] In this document, the term "module" as used herein refers to software, firmware, hardware, and any combination of these elements for performing the associated functions described herein. Additionally, for the purposes of discussion, various modules are described as discrete modules; however, as will be apparent to one of ordinary skill in the art, two or more modules may be combined to form a single module that performs the associated functions arranged according to the present solution.

[0099] In addition, memory or other storage, and communication components can be used in the arrangement of this solution. It should be understood that, for the sake of clarity, the above description has described the arrangement of this solution with reference to different functional units and processors. However, it is apparent that any suitable functional distribution can be adopted between different functional units, processing logic elements or domains, without departing from the content of this solution. For example, the function shown as being performed by a separate processing logic element or controller can be performed by the same processing logic element or controller. Therefore, reference to a specific functional unit is only a reference to a suitable means for providing the described function, and does not indicate a strict logical or physical structure or organization.

[0100] Various modifications to the embodiments described in this disclosure will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments without departing from the scope of this disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the novel features and principles disclosed herein, as set forth in the following claims.

Claims

1. A wireless communication method, comprising: A first wireless communication device among the plurality of wireless communication devices sends a first reference signal to the wireless communication node; receiving, by the first wireless communication device, a second reference signal from the wireless communication node; as well as The first wireless communication device sends a report to the wireless communication node, the report including signaling indicative of channel correlation information associated with the plurality of wireless communication devices.

2. The wireless communication method according to claim 1, wherein: The first reference signal includes a sounding reference signal SRS.

3. The wireless communication method according to claim 1, wherein: The second reference signal includes a precoded channel state information reference signal CSI-RS.

4. The wireless communication method according to claim 1, wherein: The channel correlation information includes a matrix having dimensions. The wireless communication method according to claim 4 , wherein: At least one of the dimensions is determined based on a number of the plurality of wireless communication devices. The wireless communication method according to claim 4 , wherein: At least one of the dimensions is related to the number of antennas, the number of streams, or the number of layers of any one of the plurality of wireless communication devices.

7. The wireless communication method according to claim 4, wherein: At least one of the dimensions is determined based on a number configured by the wireless communication node for the first wireless communication device.

8. The wireless communication method according to claim 4, wherein: The matrix is ​​composed of a plurality of codebook vectors.

9. The wireless communication method according to claim 4, wherein: The matrix is ​​composed of a plurality of quantized vectors.

10. The wireless communication method according to claim 1, wherein: The signaling includes a plurality of indices mapped to a basis for representing channel correlation information.

11. The wireless communication method according to claim 1, wherein: The signaling includes a plurality of parameters for quantifying channel correlation information.

12. A wireless communication method, comprising: The wireless communication node receives a first reference signal from each of the plurality of wireless communication devices; The wireless communication node transmits a second reference signal to at least a first wireless communication device among the plurality of wireless communication devices; as well as The wireless communication node receives a report from the first wireless communication device including signaling indicative of channel correlation information associated with the plurality of wireless communication devices.

13. A wireless communication device comprising a processor and a memory, wherein: The processor is configured to read code from the memory and implement the method of any one of claims 1 to 12.

14. A computer program product comprising computer-readable program medium code stored thereon, which, when executed by a processor, causes the processor to implement the method of any one of claims 1 to 12.

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