Communication method and communication apparatus

Abstract

A method is provided. The method includes: receiving a first reference signal and a second reference signal; obtaining first channel information and second channel information by performing channel measurements using the first reference signal and the second reference signal, respectively, wherein the first reference signal is transmitted on first frequency domain resources indicated by a first sampling sequence, the second reference signal is transmitted on second frequency domain resources indicated by a second sampling sequence, and the first sampling sequence and the second sampling sequence are comb coprime sequences; obtaining time delays of a full channel based on the first channel information and the second channel information; and obtaining third channel information based on the time delays, wherein the third channel information comprises full channel information.

Description

[0001] COMMUNICATION METHOD AND COMMUNICATION APPARATUS

[0002] TECHNICAL FIELD

[0003] The present disclosure generally relates to the field of wireless communication, and in particular, to a communication method and a communication apparatus.

[0004] BACKGROUND

[0005] Modem wireless systems support multiple-input multiple-output (MIMO) with orthogonal frequencydivision multiplexing (OFDM) which allows to serve many users simultaneously. For channel estimation in uplink channel, sounding reference signals (SRS) are used which located in some OFDM symbols over the whole bandwidth of the channel with some regular combs.

[0006] This background information is provided to reveal information believed by the applicant to be of possible relevance to the present disclosure. No admission is necessarily intended, nor should be construed, that any of the preceding information constitutes prior art against the present disclosure.

[0007] SUMMARY

[0008] This present disclosure provides a communication method and apparatus for channel estimation.

[0009] According to a first aspect, a method may be applied to a network side, for example, a base station (BS), a component (for example, a circuit, a chip, or a chip system) in a BS, or a logical module or software that can implement all or some functions of a BS on a network side. For example, the method is applied to a BS.

[0010] In the method, the BS receives a first reference signal and a second reference signal; obtains first channel information and second channel information by performing channel measurements using the first reference signal and the second reference signal, respectively, wherein the first reference signal is transmitted on first frequency domain resources indicated by a first sampling sequence, the second reference signal is transmitted on second frequency domain resources indicated by a second sampling sequence, and the first sampling sequence and the second sampling sequence are comb coprime sequences; obtains time delays of a full channel based on the first channel information and the second channel information; and obtains third channel information based on the time delays, wherein the third channel information comprises full channel information.

[0011] In such case, the BS may receive reference signals in given frequency domain resources based on coprime sequences. Since the first sampling sequence and the second sampling sequence are coprime sequences, the first frequency domain resources and the second frequency domain resources may be sparsely distributed on given frequency domain resources, which means that the first frequency domain resources and the second frequency domain resources may be limited within a certain number of frequency domain resources, and the remaining frequency domain resources may be used for transmitting reference signals to other users, thereby improving the utilization of the resources. In addition, the BS performs channel measurement and obtains time delays estimation of a full channel. Based on the comb coprime sequences, larger number of time delays may be obtained, thereby improving the accuracy of channel estimation.

[0012] In some other embodiments, the method in the first aspect may be applied at a terminal side, for example, a terminal or a module in a terminal, a circuit or a chip (for example, a modem (modem) chip, also referred to as a baseband (baseband) chip, or a system on chip (system on chip, SoC) chip or a system in package (system in package, SIP) chip that includes a modem core) that is responsible for a communication function in a terminal, or a logical module or software that can implement all or some functions of the terminal.

[0013] In a possible design, obtaining the time delays of the full channel based on the first channel information and the second channel information comprises: obtaining a covariance matrix based on the first channel information and the second channel information; obtaining a first vector by vectorizing the covariance matrix; and obtaining the time delays based on the first vector. The covariance matrix may be a submatrix of covariance matrix of the full channel or a partial covariance matrix of the full channel.

[0014] Based on the covariance matrix and the first vector, larger number of time delays may be obtained effectively.

[0015] In a possible design, obtaining the time delays based on the first vector comprises: obtaining a second vector by processing the first vector; and obtaining the time delays based on the second vector.

[0016] Processing the first vector may help the BS to obtain the time delays efficiently.

[0017] In a possible design, obtaining the time delays based on the second vector comprises: obtaining the time delays based on the second vector using compressed sensing or least squares.

[0018] In such case, larger number of time delays may be obtained.

[0019] In a possible design, the BS further obtains coefficients estimation, and obtaining the third channel information based on the time delays comprises: obtaining first dictionary information based on the time delays, wherein the first dictionary information is for indicating steering vectors of the full channel; and obtaining the third channel information based on the coefficients estimation and the first dictionary information.

[0020] Based on the coefficients estimation, the BS may obtain the full channel information efficiently.

[0021] In a possible design, obtaining the coefficients estimation comprises: obtaining second dictionary information for indicating steering vectors of channels in the full channel corresponding to the first sampling sequence and the second sampling sequence; obtaining frequency response information for indicating frequency response of the channels corresponding to the first sampling sequence and the second sampling sequence; and obtaining the coefficients estimation based on the second dictionary information and the frequency response information.

[0022] In such case, the BS may obtain the coefficients estimation based on the second dictionary information and the frequency response information, and the coefficients estimation may be obtained effectively.

[0023] In a possible design, the first sampling sequence has a step of C * Pt, and the second sampling sequence has a step of C * P2, where C is a regular transmission comb value, Pris a first coprime step value, P2is a second coprime step value, C, P and P2are positive integers, and P1is coprime to P2.

[0024] In such case, the first frequency domain resources and the second frequency domain resources may be sparsely distributed on given frequency domain resources, thereby improving the utilization of the resources. In a possible design, a number of elements in the first sampling sequence is approximately^ / ^ — 1), and a number of elements in the second sampling sequence is approximately (f — 1).

[0025] In such case, elements in the first sampling sequence may be determined based on a minimum of values of elements in the first sampling sequence, the step of the first sampling sequence, and the number of elements in the first sampling sequence. Elements in the second sampling sequence may be determined similarly.

[0026] In a possible design, P1and P2are determined based on a quantity of resource units in the frequency domain resources.

[0027] In a possible design, Pxand P2satisfy: Nsc« (2P2— 1) • CPr, where Nscis the quantity of the resource units in the frequency domain resources.

[0028] In a possible design, the first frequency domain resources comprise multiple first frequency units, and indices of the first frequency units are determined based on a starting position of the first frequency units, the regular transmission comb value C , and the first coprime step value PTand the second frequency domain resources comprise multiple second frequency units, and indices of the second frequency units are determined based on a starting position of the second frequency units, the regular transmission comb value C , and the second coprime step value P2.

[0029] In a possible design, the BS further transmitting first information for indicating at least one of: time domain resources for transmitting the first reference signal and / or the second reference signal, quantity of time domain units in the time domain resources for transmitting the first reference signal and / or the second reference signal, a starting position of the first frequency domain resources and / or a starting positing of the second frequency domain resources, the regular transmission comb value C, the first coprime step value P±, the second coprime step value P2, or an index of the first information associated to the first reference signal and / or the second signal.

[0030] I this case, the UE may receive the first information and determine the first sampling sequence and / or the second sampling sequence based on the first information.

[0031] According to a second aspect, a communication method is described. The method may be applied at a terminal side, for example, a terminal or a module in a terminal, a circuit or a chip (for example, a modem (modem) chip, also referred to as a baseband (baseband) chip, or a system on chip (system on chip, SoC) chip or a system in package (system in package, SIP) chip that includes a modem core) that is responsible for a communication function in a terminal, or a logical module or software that can implement all or some functions of the terminal. For example, the method is applied to a user equipment (UE) which is an example of the terminal.

[0032] In this method, the UE determines a first sampling sequence and a second sampling sequence, wherein the first sampling sequence is for indicating first frequency domain resources, the second sampling sequence is for indicating second frequency domain resources, and the first sampling sequence and the second sampling sequence are coprime sequences; transmits a first reference signal on the first frequency domain resources based on the first sampling sequence; and transmits a second reference signal on the second frequency domain resources based on the second sampling sequence.

[0033] In some other embodiments, the method in the second aspect may be applied to a network side, for example, a base station (BS) or a component (for example, a circuit, a chip, or a chip system) in a BS on a network side.

[0034] In a possible design, the first sampling sequence has a step of C * P , and the second sampling sequence has a step of C * P2, Pi , where C is a regular transmission comb value, Pj is a first coprime step value, P2is a second coprime step value, C, fyand P2are positive integers, and fy is coprime to P2.

[0035] In a possible design, a number of elements in the first sampling sequence is approximately (2P2- 1) and a number of elements in the second sampling sequence is P±— 1).

[0036] In a possible design, fy and P2are determined based on a quantity of resource units in the frequency domain resources.

[0037] In a possible design, fy and2satisfy: Nsc« (2P2- 1) ■ CP1;where Nscis the quantity of the resource units in the frequency domain resources.

[0038] In a possible design, the first frequency domain resources comprise multiple first frequency units, and indices of the first frequency units are determined based on a starting position of the first frequency units, the regular transmission comb value C , and the first coprime step value Pr; and the second frequency domain resources comprise multiple second frequency units, and indices of the second frequency units are determined based on a starting position of the second frequency units, the regular transmission comb value C , and the second coprime step value P2.

[0039] In a possible design, the UE further receives first information for indicating at least one of: time domain resources for transmitting the first reference signal and / or the second reference signal, quantify of time domain units in the time domain resources for transmitting the first reference signal and / or the second reference signal, a starting position of the first frequency domain resources and / or a starting positing of the second frequency domain resources, the regular transmission comb value C, the first coprime step value P1?the second coprime step value P2, or an index of the first information associated to the first reference signal and / or the second signal, wherein determining the first sampling sequence and the second sampling sequence comprises: determining the first sampling sequence and the second sampling sequence based on the first information.

[0040] According to a third aspect, a communication apparatus is described. The communication apparatus has a function of implementing the first aspect. For example, the communication apparatus includes a corresponding module, unit, or means (means) for performing operations in the first aspect. The module, unit, or means may be specifically implemented by using software, may be implemented by using hardware, or may be implemented by using software in combination with hardware.

[0041] According to a fourth aspect, a communication apparatus is described. The communication apparatus has a function of implementing the second aspect. For example, the communication apparatus includes a corresponding module, unit, or means (means) for performing operations in the second aspect. The module, unit, or means may be specifically implemented by using software, may be implemented by using hardware, or may be implemented by using software in combination with hardware.

[0042] According to a fifth aspect, another a communication apparatus is described. The communication apparatus includes a memory and one or more processors. The memory is configured to store a part or all of a necessary computer program or instructions for implementing a function in the first aspect. The one or more processors may execute the computer program or the instructions, and when the computer program or the instructions is / are executed, the communication apparatus is enabled to implement the method in any possible design or implementation of the first aspect.

[0043] In some embodiments, the communication apparatus may further include an interface circuit, and the processor is configured to communicate with another apparatus or component through the interface circuit.

[0044] The communication apparatus may be network side, for example, a base station (BS) or a component (for example, a circuit, a chip, or a chip system) in a BS on a network side.

[0045] According to a sixth aspect, another a communication apparatus is described. The communication apparatus includes a memory and one or more processors. The memory is configured to store a part or all of a necessary computer program or instructions for implementing a function in the second aspect. The one or more processors may execute the computer program or the instructions, and when the computer program or the instructions is / are executed, the communication apparatus is enabled to implement the method in any possible design or implementation of the second aspect.

[0046] The communication apparatus may be a terminal, a module in a terminal, or a chip responsible for a communication function in a terminal, for example, a modem chip (also referred to as a baseband chip) or an SoC chip or an SIP chip that includes a modem module.

[0047] According to a seventh aspect, a communication system is described, the communication system comprising a first communication apparatus configured to implement the method in any possible design or implementation of the first aspect and a second communication apparatus configured to implement the method in any possible design or implementation of the second aspect.

[0048] According to an eighth aspect, a computer-readable storage medium is described. The computer-readable storage medium stores computer-readable instructions, and when a computer reads and executes the computer- readable instructions, the computer is enabled to perform the method in any one of the possible designs of the first aspect to the second aspect.

[0049] According to a ninth aspect, this application provides a computer program product. When a computer reads and executes the computer program product, the computer is enabled to perform the method in any one of the possible designs of the first aspect to the second aspect.

[0050] This application encompasses various embodiments, including not only method embodiments, but also other embodiments such as apparatus embodiments and embodiments related to non- transitory computer readable storage media. Embodiments may incorporate, individually or in combinations, the features disclosed herein.

[0051] BRIEF DESCRIPTION OF THE DRAWINGS

[0052] For a better understanding of the various described embodiments, reference should be made to the Detailed Description below, in conjunction with the following drawings in which like reference numerals refer to corresponding parts throughout the figures. FIG. 1 illustrates an example communication system in which embodiments of the present disclosure may be implemented;

[0053] FIG. 2 illustrates another example communication system in which embodiments of the present disclosure may be implemented;

[0054] FIG. 3 illustrates an example communication system in which an apparatus wirelessly communicates with another apparatus, in accordance with some embodiments of the present disclosure;

[0055] FIG. 4 illustrates an example apparatus in accordance with some embodiments of the present disclosure;

[0056] FIG. 5 illustrates an example apparatus in accordance with some embodiments of the present disclosure;

[0057] FIG. 6 is a schematic diagram illustrating reference signal mapping of regular comb-like structure in accordance with some embodiments of the present disclosure;

[0058] FIGS. 7A-7C are schematic diagrams illustrating sampling effects using different sampling patterns in accordance with some embodiments of the present disclosure;

[0059] FIG. 8 illustrates a device interaction diagram in accordance with some embodiments of the present disclosure;

[0060] FIG. 9 is a schematic diagram illustrating communication of parameters for channel estimation in accordance with some embodiments of the present disclosure;

[0061] FIGS. 10A and 10B are schematic diagrams illustrating properties of difference between samplings in accordance with some embodiments of the present disclosure;

[0062] FIG. 11 is a schematic diagram illustrating properties of Gram matrix obtained based on difference between samplings in accordance with some embodiments of the present disclosure;

[0063] FIG. 12 is a schematic diagram illustrating an example of resource allocation where both samplings are assigned into one OFDM symbol in accordance with some embodiments of the present disclosure;

[0064] FIG. 12 is a schematic diagram illustrating an example of resource allocation where two samplings are assigned into two OFDM symbols in accordance with some embodiments of the present disclosure; and

[0065] FIG. 13 is a schematic diagram illustrating simulation results with different sampling manners in accordance with some embodiments of the present disclosure.

[0066] DETAILED DESCRIPTION

[0067] Numerous details are described herein to provide a thorough understanding of the example embodiments illustrated in the accompanying drawings. However, some embodiments may be practiced without many of the specific details, and the scope of the claims is only limited by those features and aspects specifically recited in the claims. Furthermore, well-known processes, components, and materials have not necessarily been described in exhaustive detail so as to avoid obscuring pertinent aspects of the embodiments described herein.

[0068] The solutions described in this disclosure are applicable to a wide range of communication networks, such as a future generation network, or a legacy (e.g., 5G, fourth generation (4G), third generation (3G) or second generation (2G)) network. The solutions may also be implemented in Wi-Fi, non-terrestrial network (NTN), cloud and edge computing service, sensing services, or distributed or self-organized networks. In an example, the solutions may be applied to automated manufacturing systems in smart factories. In another example, the solutions may be applied to other intelligent vertical scenarios such as ports, delivery systems and medical systems.

[0069] FIG. 1 illustrates an example communication system in which embodiments of the present disclosure may be implemented. The communication system 100 includes a radio access network (RAN) 120, one or more communication electronic devices (EDs) 110a, 110b, 110c, HOd, I lOe, 11 Of, 110g, 11 Oh, HOi, HOj (collectively referred to as 110), a core network (CN) 130, a Public Switched Telephone Network (PSTN) 140, the Internet 150, and other networks 160.

[0070] The RAN 120 may include, but is not limited to, a future generation RAN, or a legacy RAN such as, but not limited to, 5G, 4G, 3G or 2G radio access network. The RAN 120 may be, for example, an Evolved Universal Mobile Telecommunications System (UMTS) Terrestrial Radio Access Network (E-UTRAN), a NextGen RAN (NG RAN), or some other type of RAN. Examples of RAN 120 based on the evolution of telecommunications standards include, but are not limited to, Global System for Mobile Communications (GSM) and Code Division Multiple Access (CDMA) for 2G, Universal Mobile Telecommunications System (UMTS) based on Wideband Code Division Multiple Access (WCDMA) and CDMA2000 for 3G, Long-Term Evolution (LTE) and Worldwide Interoperability for Microwave Access (WiMAX) for 4G, and NR for 5G. In some implementations, the RAN 120 may use any radio access technology (RAT) in the wireless interface between the one or more EDs 110 and the RAN 120. In some implementations, the term “radio access” may refer to the future generation air interface standards which may include both terrestrial networks (TNs) and non-terrestrial networks (NTNs). These networks will be described in greater detail below in conjunction with various implementations.

[0071] The one or more communication EDs 110 (also referred to as “user equipment”) are configured to connect (e.g. be communicatively coupled) with each other or to one or more network nodes 170a, 170b (collectively referred to as 170) in the RAN 120.

[0072] The CN 130 is a part of the communication system 100 and consists of network nodes (e.g. 170a, 170b) which provide support for the network features and telecommunication services. In some implementations, the CN 130 may be dependent on the RAT used in the communication system 100. In other implementations, the CN 130 may be access-agnostic, that is, the CN 130 may be independent of the RAT used in the communication system 100. There are different types of CN 130 for different 3GPP system generations. For example, the CN 130 is the Evolved Packet Core (EPC) in 4G, also known as the Evolved Packet System (EPS). In another example, the CN 130 is the 5G Core (5GC) which was developed as part of the 5G System (5GS). The CN 130 also enables integration of different 3GPP and non-3GPP access types. In some implementations and referring to FIG. 1, the CN 130 also provides the interface towards external networks that may include the PSTN 140, the Internet 150, and other networks 160 in the communication system 100.

[0073] In general, the communication system 100 facilitates interaction between multiple wireless or wired elements. The communication system 100 may transmit different types of content, such as voice, data, video, and / or text, through different transmission methods such as, but not limited to, broadcast, multicast, groupcast, and unicast. Additionally, the communication system 100 operates by allocating and / or sharing resources, such as carrier spectrum bandwidth, among its constituent elements.

[0074] The communication system 100 may provide a wide range of communication services and applications including, but not limited to, Enhanced Mobile Broadband (eMBB) services, Ultra-Reliable Low-Latency Communication (URLLC) services, Massive Machine Type Communication (mMTC) services, Integrated Sensing And Communication (ISAC), immersive communication, Ultra-massive Machine-Type Communication (uMTC), hyper reliable and low-latency communication, ubiquitous connectivity, integrated artificial intelligence (Al) and communication, and other services that can be provided by a future generation communication system. The communication system 100 may provide other services and applications such as, but not limited to, earth monitoring, remote sensing, passive sensing and positioning, navigation and tracking, autonomous delivery and mobility and the like.

[0075] The communication system 100 may include a terrestrial communication system (or network) and / or a nonterrestrial communication system (or network). The communication system 100 may provide a high degree of availability and robustness through a joint operation of the terrestrial communication system and the non-terrestrial communication system. For example, integrating a non-terrestrial communication system (or components thereof) into a terrestrial communication system can result in a heterogeneous network comprising multiple layers. The heterogeneous network may achieve better overall performance through efficient multi-link joint operation, more flexible functionality sharing, and faster physical layer link switching between terrestrial networks and nonterrestrial networks. The terrestrial communication system and the non-terrestrial communication system could be considered as sub-systems of the communication system 100.

[0076] FIG. 2 illustrates another example communication system 100 in which embodiments of the present disclosure may be implemented. The communication system 100 includes EDs 110a, 110b, 110c, 11 Od (collectively referred to as ED 110), RANs 120a, 120b, one or more CNs 130, a PSTN 140, the Internet 150, and other networks 160. Additionally, the communication system 100 may also include a non-terrestrial network (NTN) 120c.

[0077] The RANs 120a and 120b may include network nodes 170a and 170b respectively. Examples of network nodes 170a, 170b include base stations, which can be generally referred to as terrestrial network (TN) devices or terrestrial transmit and receive points (T-TRPs) 170a and 170b (collectively referred to as 170). In this context, the terms "TRP" and "base station" are used interchangeably unless otherwise specified. For simplicity, this disclosure primarily refers to network nodes as base stations; however, unless explicitly stated otherwise, references to TRP are considered non-limiting and interchangeable. The T-TRPs 170a, 170b may be base stations mounted on a building or tower.

[0078] In one implementation, the NTN 120c includes a RAN node such as a base station 172, which may be generally referred to as an NTN device, a non-terrestrial node, a non-terrestrial network device, a non-terrestrial base station, or a non-terrestrial transmit and receive point (NT-TRP) 172.

[0079] In some implementations, the NT-TRP 172 is not attached to the ground, for example, as in the case of an airborne base station. An airborne base station may be implemented using communication equipment supported or carried by a flying device. For example, a flying device may include, but is not limited to, an airborne platform (such as a blimp or an airship), balloon, drone (such as quadcopter), and other types of aerial vehicles. In some implementations, an airborne base station may be supported or carried by an unmanned aerial system (UAS) or an unmanned aerial vehicle (UAV), such as a drone. An airborne base station may be a moveable or mobile base station that can be flexibly deployed in different locations to meet network demand. A satellite base station is another example of a non-terrestrial base station. A satellite base station may be implemented using communication equipment supported or carried by a satellite. A satellite base station may also be referred to as an orbiting base station. High altitude platforms are yet another example of non-terrestrial base stations, including international mobile telecommunication base stations.

[0080] As referred to herein, and unless specified otherwise, a “TRP” may also refer to a T-TRP or an NT-TRP, a “T-TRP” may also refer to a “TN TRP”, and an “NT-TRP” may also refer to an “NTN TRP”. The NTN 120c may be considered a RAN, sharing operational aspects with RANs 120a, 120b. The NTN 120c may include at least one NTN device and at least one corresponding terrestrial network device. The at least one NTN device may function as a transport layer device and the at least one corresponding terrestrial network device may function as a RAN node, communicating with the ED 110 via the NTN device. Additionally, there may be an NTN gateway on the ground (referred to as a terrestrial network device) that also functions as a transport layer device facilitating communication with both the NTN device and the RAN node. The RAN node may communicate with the ED 110 via the NTN device and the NTN gateway. In some implementations, the NTN gateway and the RAN node may be located within the same device.

[0081] A base station 170 (also referred to as a TRP as stated above) is a network element within a radio access network responsible for radio transmission and reception in one or more cells to or from the ED (such as a user equipment). In different implementations, the base station 170 may also be known as a base transceiver station (BTS), a radio base station, a network node, a network device, a device on the network side, a transmit / receive node, a Node B, an evolved NodeB (eNodeB or eNB), a Home eNodeB, a next Generation NodeB (gNB), a transmission point (TP), a site controller, an access point (AP), a wireless router, a relay station, a terrestrial node, a terrestrial network device, a terrestrial base station, a non-terrestrial node, a non-terrestrial network device, a non-terrestrial base station, and a positioning node, among other possibilities. The base station 170 may be a macro base station (BS), a pico BS, a relay node, a donor node, or combinations thereof. When the base station 170 performs (or is configured to perform) a method described herein, it may be interpreted as the base station itself, one or more modules (or units) in the base station, a circuit or chip, or a combination thereof, performing the method. For example, the circuit or chip may include a modem chip, also referred to as a baseband chip, a system on chip (SoC) including a modem core, system in package (SIP)), and the like, and may be responsible for one or more communication functions within the base station.

[0082] The EDs llOa-HOd and TRPs 170a- 170b, 172 are examples of communication equipment configured to implement some or all of the operations and / or implementations described herein. The TRP 170a forms part of the RAN 120a, which may include other TRPs, and / or other devices. Also, the TRP 170b forms part of the RAN 120b, which may include other TRPs, and / or other devices. Each TRP 170a, 170b may transmit and / or receive wireless signals within a particular geographic region or area, sometimes referred to as a “cell” or a “coverage area”. The TRPs 170a- 170b may be responsible for allocating and / or configuring resources and transmission and / or reception in a set of cell(s). A cell is a radio network object that can be uniquely identified by a cell identification that is broadcasted over a geographical region or area from base stations associated with the cell. A cell can work in either frequency-division duplex (FDD) or time-division duplex (TDD) mode. A cell may be further divided into cell sectors, and base stations 170a- 170b may, for example, employ one or more transceivers to provide services to one or more sectors. Some implementations may include pico or femto cells if supported by the radio access technology. In some implementations, one or more transceivers could be used for each cell, such as with Multiple-Input Multiple- Output (MIMO) technology. The number of RANs 120a-120b shown is merely an example. Any number of RANs may be contemplated when designing the communication system 100.

[0083] A base station may be a single element, as shown in the figures, or multiple elements distributed throughout the corresponding RAN, or otherwise configured. In some implementations, a plurality of RAN nodes coordinate to assist the ED 110 in implementing radio access, and different RAN nodes separately implement and handle different functions of the base station. For example, the RAN node may be a central unit (CU), a distributed unit (DU), a CU- control plane (CP), a CU-user plane (UP), or a radio unit (RU), etc. The CU and the DU may be separately deployed, or included within the same element (e.g., a baseband unit (BBU)). The RU may be included in a radio frequency device or a radio frequency unit (e.g., a remote radio unit (RRU), an active antenna unit (AAU), or a remote radio head (RRH)). In different systems, the CU (or the CU-CP, the CU-UP), the DU, or the RU may be known by different names, but their functions are understood by a person skilled in the art. For example, in an open radio access network (ORAN) system, a CU may be referred to as an open CU (O-CU), a DU may be referred to as an open DU (O-DU), and a CU-CP may be referred to as an open CU-CP (O-CU-CP). The CU-UP may also be referred to as an open CU- UP (O-CU-UP), and the RU may also be referred to as an open RU (O-RU). Any one of the CU (or the CU-CP, the CU-UP), the DU, and the RU may be implemented using a software module, a hardware module, or a combination of a software module and a hardware module.

[0084] Furthermore, communication between different devices / apparatuses in various implementations of this disclosure may refer to direct communication (that is, without the need of forwarding by another device / apparatus), or may refer to communication(s) between different devices / apparatuses via another device / apparatus (that is, requiring forwarding by another device / apparatus). Alternatively, such communication(s) may involve one functional unit inside a device / apparatus using another functional unit within the device / apparatus to communicate with another device / apparatus. In other words, phrases such as "sending (or transmitting) information to... (an ED or a base station)" in this disclosure may be understood as a destination endpoint of the information being an ED or a base station, including, sending / transmitting information directly or indirectly to an ED or a base station. Similarly, phrases like "receiving information from... (an ED or a base station)" may be understood as a source endpoint of the information being an ED or a base station, including directly or indirectly receiving information from an ED or a base station. Between the source endpoint that sends the information and the destination endpoint, necessary processing such as, but not limited to, format conversion, digital-to-analog conversion, amplification, and filtering may be performed on the information. However, the destination endpoint may understand valid information from the source endpoint. A similar understanding applies to other descriptions in this disclosure without reiterating details already described. In the present disclosure, the terms "send" and "transmit" may be used interchangeably in different implementations of this disclosure.

[0085] The ED 110 is used to connect people, objects, machines, and other entities. The ED 110 may be widely used in various scenarios including, but not limited to, cellular communications, device-to-device (D2D), vehicle to everything (V2X), peer-to-peer (P2P), machine-to-machine (M2M), machine-type communication (MTC), internet of things (loT), virtual reality (VR), augmented reality (AR), mixed reality (MR), metaverse, digital twin, industrial control, self-driving, remote medical, smart grid, smart furniture, smart office, smart wearable, smart transportation, smart city, drones, robots, remote sensing, passive sensing, positioning, navigation and tracking, and autonomous delivery and mobility.

[0086] Each ED 110 represents any suitable end user device for wireless operation and may include devices such as (or may be referred to as, but not limited to) a user equipment (UE) or a user device or a terminal device, a wireless transmit / receive unit (WTRU), a mobile station, a fixed or mobile subscriber unit, a cellular telephone, a station (STA), an MTC device, a personal digital assistant (PDA), a smartphone, a laptop, a computer, a tablet, a wireless sensor, a consumer electronics device, a smart book, a vehicle, a car, a truck, a bus, a train, or an loT device, wearable devices (such as a watch, a pair of glasses, head mounted equipment, etc.), an industrial device, or an apparatus (such as a module, modem, or chip) in the forgoing devices, among other possibilities. Future generation EDs 110 may be referred to by other terms. When an ED 110 performs (or is configured to perform) a method described herein, it may be interpreted as the ED itself, one or more modules (or units) in the ED, a circuit or chip, or a combination thereof, performing the method. For example, the circuit or chip may include a modem chip, also referred to as a baseband chip, a system on chip (SoC) including a modem core, system in package (SIP)), or the like, and may be responsible for one or more communication functions in the ED.

[0087] Each ED 110 connected to TRPs 170a- 170b, and / or TRPs 172 can be dynamically or semi-statically turned- on (i.e. established, activated, or enabled), turned-off (i.e. released, deactivated, or disabled) and / or configured in response to one or more of: connection availability and connection necessity.

[0088] Any ED 110 may be alternatively or additionally configured to interface, access, or communicate with any of the TRPs 170a, 170b and 172, the Internet 150, the CN 130, the PSTN 140, the other networks 160, or any combination thereof. In some examples, the ED 110a may communicate an uplink (UL) and / or downlink (DL) transmission over a terrestrial air interface 190a with station-TRP 170a. In some examples, the EDs 110a, 110b, 110c, and 1 lOd may also communicate directly with one another via one or more sidelink (SL) air interfaces 190b. In some examples, the EDs 110a, HOd may communicate using an UL and / or DL transmission over a non-terrestrial air interface 190c with NT-TRP 172.

[0089] An air interface (such as, for example, 190a, 190b, 190c) generally includes a number of components and associated parameters that collectively specify how a transmission is to be sent and / or received over a wireless i i communications link between two or more communicating devices such as EDs and base station(s). For example, an air interface may include one or more components defining the waveform(s), frame structure(s), multiple access scheme(s), protocol(s), coding scheme(s) and / or modulation scheme(s) for conveying information (such as, data) over a wireless communications link. The air interfaces 190a and 190b may use similar communication technology that may include any suitable radio access technology.

[0090] The non-terrestrial air interface 190c can enable communication between the EDs 110a, HOd and one or more NT-TRPs 172 via a wireless link or simply a link. For some examples, the link is a dedicated connection for unicast transmission, a connection for broadcast transmission, or a connection between a group of EDs 110 and one or more NT-TRPs 172 for multicast transmission.

[0091] The TRPs 170a- 170b, 172 may communicate with one another over one or more air interfaces 190e, 190f using wireless communication links (such as radio frequency (RF), microwave, infrared (IR), etc.) or wired communication links. The air interfaces 190e, 190f may utilize any suitable radio access technology, and may be substantially similar to the air interfaces 190a, 190c over which the EDs 110a-l lOd communicate with one or more ofthe TRP 170a-170b, 172 or they may be substantially different. For example, the communication system 100 may implement one or more channel access methods, such as Time Division Multiple Access (TDMA), Frequency Division Multiple Access (FDMA), Code Division Multiple Access (CDMA), Single Carrier Frequency Division Multiple Access (SC-FDMA), Low Density Signature Multicarrier Code Division Multiple Access (LDS-MC- CDMA), Non-Orthogonal Multiple Access (NOMA), Pattern Division Multiple Access (PDMA), Lattice Partition Multiple Access (LPMA), Resource Spread Multiple Access (RSMA), and Sparse Code Multiple Access (SCMA).

[0092] The RANs 120a and 120b are in communication with the CN 130 to provide the EDs 110a 110b, and 110c with various services such as voice, data, multimedia, and other services. The RANs 120a and 120b and / or the CN 130 may be in direct or indirect communication with one or more other RANs (not shown), which may or may not be directly served by the CN 130, and may employ different radio access technologies from RAN 120a and / or RAN 120b. The CN 130 may also serve as a gateway access between (i) the RANs 120a and 120b and / or the EDs 110a 110b, and 110c, and (ii) other networks (such as the PSTN 140, the Internet 150, and the other networks 160). In addition, some or all of the EDs 110a 110b, and 110c may include functionality for communicating with different wireless networks over different wireless links using different wireless technologies and / or protocols. For example, the EDs 110a 110b, and 110c communicate using different cellular communications protocols, such as, but not limited to, a Global System for Mobile Communications (GSM) protocol, a code-division multiple access (CDMA) network protocol, a Push-to-Talk (PTT) protocol, a PTT over Cellular (POC) protocol, a Universal Mobile Telecommunications System (UMTS) protocol, a 3GPP Long Term Evolution (LTE) protocol, a 5G protocol, a New Radio (NR) protocol, and the like. Instead of wireless communication (or in addition thereto), the EDs 110a 110b, and 110c may communicate using wired communication channels to a service provider or switch (not shown), and / or to the Internet 150. The PSTN 140 may include circuit switched telephone networks for providing plain old telephone service (POTS). The Internet 150 may include a network of computers and subnets (intranets) or both, and incorporate protocols, such as internet protocol (IP), transmission control protocol (TCP), user datagram protocol (UDP). The EDs 110a 110b, and 110c may be multimode devices capable of operation according to multiple radio access technologies, and may incorporate one or multiple transceivers necessary to support such.

[0093] In addition, the communication system 100 may include a sensing agent (not shown) to manage the sensed data from ED 110 and / or any one of TRPs 170a, 170b, 172. In one implementation, the sensing agent may be part of any one of TRPs 170a, 170b, 172. In another implementation, the sensing agent is a separate node that can communicate with the CN 130 and / or the RAN 120 (such as any one of TRPs 170a, 170b, 172).

[0094] FIG. 3 illustrates an example communication system (e.g. the communication system 100) in which an apparatus 310 wirelessly communicates with another apparatus 320 in accordance with some embodiments of the present disclosure. The apparatus 310 may be an electronic device (such as ED 110). The apparatus 320 may be a network node (e.g. the network node 170) such as a T-TRP 170 a, 170b or an NT-TRP 172. Although only one apparatus 310 and one apparatus 320 are shown in this figure, the number of apparatus 310 and / or number of apparatus 320 can vary, potentially including one or more of each. For example, a single ED 110 may be served by a single T-TRP 170 (or a single NT-TRP 172), or by multiple T-TRPs 170 (or multiple NT-TRPs 172). Similarly, a single ED 110 may be served by one or more T-TRPs 170 and one or more NT-TRPs 172. Similarly, a single T-TRP 170 (or a single NT-TRP 172) may serve one or more EDs 110.

[0095] The apparatus 310 may include one or more processors 210. For clarity and to avoid overcrowding the illustration, only a single processor 210 is illustrated. The apparatus 310 may fiirther include a transmitter 201 and a receiver 203 coupled to one or more antennas 204. For clarity, only a single antenna 204 is illustrated. One, some, or all of the antennas 204 may alternatively be panels. In some implementations, the transmitter 201 and the receiver 203 are separate from each other. In other implementations, the transmitter 201 and the receiver 203 may be integrated into a single unit, for example, as a transceiver. The transceiver is configured to modulate data or other content for transmission by the one or more antennas 204 or a network interface controller (NIC). The transceiver may also be configured to demodulate data or other content received by the one or more antennas 204. A transceiver may include any suitable structure for generating signals for wireless or wired transmission and / or for processing signals received through wireless or wired communication. Each antenna 204 includes any suitable structure for transmitting and / or receiving wireless or wired signals. The apparatus 310 may include a memoiy 208. In some implementations, the apparatus 310 may include multiple memories 208. Only a single transmitter 201 , receiver 203, processor 210, memory 208, and antenna 204 is illustrated for simplicity, but the apparatus 310 may include one or more other components. In some implementations of the present disclosure, the transceiver (or transmitter 201 and / or receiver 203) may be viewed as an interface circuit.

[0096] The memoiy 208 is configured to store instructions used to perform operations described herein. The memoiy 208 may also be configured to store data that is used, generated, or collected by the apparatus 310. For example, the memory 208 can store software instructions or modules configured to implement some or all of the functionalities and / or operations described herein and that which are executed by the one or more processors 210.

[0097] The apparatus 310 may further include one or more input / output devices (not shown) or interfaces. The input / output devices or interfaces facilitate interaction with a user or other devices in the network. Each input / output device or interface includes suitable components for facilitating transmission of information to a user and reception of information from a user, and for various network interface communications. Such components may include, but are not limited to, a speaker, microphone, keypad, keyboard, display, touch screen, and the like.

[0098] The processor 210 may be configured to perform (or control the apparatus 310 to perform) operations (or methods) described herein as being performed by the apparatus 310. For example, the processor 210 performs or controls the apparatus 310 to perform the operations of: a) receiving one or more transport blocks (TBs), b) using a resource for decoding at least one of the received TBs, c) releasing the resource for decoding another of the received TBs, and / or d) receiving configuration information configuring a resource. For example, the operations may include tasks related to: preparing a transmission for UL transmission to the apparatus 320, processing DL- transmissions received from the apparatus 320, and handling SL transmission to and from another apparatus 310. Processing operations related to preparing a transmission for UL transmission may include operations such as, but not limited to, encoding, modulating, transmit beamforming, and generating symbols for transmission. Processing operations related to processing DL transmissions may include operations such as, but not limited to, receive beamforming, demodulating and decoding received symbols. Processing operations related to processing SL transmissions may include operations such as, but not limited to, transmit / receive beamforming, modulating / demodulating and encoding / decoding symbols. Depending upon the implementation, a DL transmission may be received by the receiver 203, possibly using receive beamforming, and the processor 210 may extract signaling from the DL transmission (such as by detecting and / or decoding the signaling). An example of signaling may be a reference signal transmitted by the apparatus 320. In some implementations, the processor 210 implements the transmit beamforming and / or the receive beamforming based on the indication of beam direction, such as beam angle information (BAI), received from the apparatus 320. In some implementations, the processor 210 may be configured to perform operations relating to network access (such as initial access) and / or downlink synchronization, which includes operations for detecting a synchronization sequence, decoding and obtaining the system information, and the like. In some implementations, the processor 210 may perform channel estimation, such as using a reference signal received from the apparatus 320.

[0099] Although not illustrated, in some implementations, the processor 210 may either be a part of the transmitter 201 or a part of the receiver 203 or a part of both the transmitter 201 and the receiver 203. Although not illustrated, in some implementations, the memory 208 may be a part of the processor 210.

[0100] The processor 210, along with the processing components of the transmitter 201 and the receiver 203, may each be implemented by one or more processors that may be the same or different. These processors are configured to execute instructions stored in a memory (such as in the memory 208).

[0101] The apparatus 320 includes one or more processors 260 (only one processor 260 is illustrated). The apparatus 320 may further include one or more transmitters 252 and one or more receivers 254 coupled to one or more antennas 256. Only a single antenna 256 is illustrated to avoid clutter in the illustration. One, some, or all of the antennas 256 may alternatively be panels. In some implementations, the transmitter 252 and the receiver 254 are separate from each other. In other implementations, the transmitter 252 and the receiver 254 may be integrated into a single unit such as, for example, as a transceiver. The apparatus 320 may further include a memory 258. In some implementations, the apparatus 320 may include multiple memories 258. The apparatus 320 may further include a scheduler 253. Only a single transmitter 252, receiver 254, processor 260, memory 258, antenna 256 and scheduler 253 is illustrated for simplicity, however the apparatus 320 may include one or more other components. In some implementations, the transceiver (or transmitter 252 and / or receiver 254) may be viewed as an interface circuit.

[0102] In some implementations, various components of the apparatus 320 may be distributed. For example, some of the modules of the apparatus 320 may be located remotely from the equipment housing the antennas 256 for the apparatus 320 (and therefore also can be viewed as one or more nodes). These modules, which can be considered as one or more nodes, may be coupled to the equipment that houses the antennas 256 over a communication link (not shown), sometimes referred to as front haul, such as the Common Public Radio Interface (CPRI). Therefore, in some implementations, the term apparatus 320 may also refer to network-side nodes that perform processing operations such as, but not limited to, determining the location of the apparatus 310, resource allocation (scheduling), message generation, and encoding / decoding, and that which are not necessarily part of the equipment that houses the antennas 256 of the apparatus 320. The nodes may also be coupled to other apparatuses 320. In some implementations, the apparatus 320 may actually be a plurality of nodes that are operating together to serve the apparatus 310, such as through the use of coordinated multipoint transmissions, or through the use of ORAN system as described above in the disclosure.

[0103] The processor 260 is configured to perform operations including those related to: preparing a transmission for DL transmission to the apparatus 310, processing an UL transmission received from the apparatus 310, preparing a transmission for backhaul transmission to another apparatus 320, and processing a transmission received over backhaul from another apparatus 320. Processing operations related to preparing a transmission for DL or backhaul transmission may include operations such as, but not limited to, encoding, modulating, precoding (such as MIMO precoding), transmit beamforming, and generating symbols for transmission. Processing operations related to processing received transmissions in the UL or over backhaul may include operations such as, but not limited to, receive beamforming, demodulating received symbols, and decoding received symbols. The processor 260 may also be configured to perform operations related to network access (such as initial access) and / or DL synchronization, such as generating the content of synchronization signal blocks (SSBs), generating the system information, and the like. In some implementations, the processor 260 is further configured to generate an indication of beam direction, such as BAI, which may be scheduled for transmission by the scheduler 253 which will be described below. In some implementations, the processor 260 implements the transmit beamforming and / or receive beamforming based on beam direction information (such as BAI) received from another apparatus 320. The processor 260 is configured to perform other network side processing operations described herein, such as, but not limited to, determining the location of the apparatus 310, determining where to deploy another apparatus 320, and the like. In some implementations, the processor 260 may generate signaling data, to configure one or more parameters of the apparatus 310 and / or one or more parameters of another apparatus 320. Any signaling data generated by the processor 260 is sent by the transmitter 252. In some implementations, the apparatus 320 implements physical layer processing. In some implementations, the apparatus 320 may perform higher layer functions such as those at the Medium Access Control (MAC) or Radio Link Control (RLC) layers in addition to physical layer processing.

[0104] In the apparatus 320, the scheduler 253 may be coupled to the processor 260 or integrated within the processor 260. In some implementations, the scheduler 253 may be integrated within the apparatus 320 or may be operated separately from the apparatus 320. The scheduler 253 may schedule UL, DL, SL, and / or backhaul transmissions, including issuing scheduling grants and / or configuring scheduling-free (such as “configured grant”) resources.

[0105] The apparatus 320 may further include a memory 258 that is configured to store instructions for performing the operations described herein. The memory 258 may also store data that is used, generated, or collected by the apparatus 320. For example, the memory 258 can store software instructions or modules configured to implement some or all of the functionalities and / or implementations described herein and that which are executed by the processor 260.

[0106] Although not illustrated, the processor 260 may be implemented as part of the transmitter 252 and / or a part of the receiver 254. Although not illustrated, in some implementations, the processor 260 may implement the scheduler 253 and the memory 258 may be implemented as part of the processor 260.

[0107] The processor 260, the scheduler 253, the processing components of the transmitter 252, and the processing components of the receiver 254 may each be implemented by the same or different processors that are configured to execute instructions stored in a memory, such as in the memory 258.

[0108] The apparatus 320 and / or the apparatus 310 may include other components not shown or described herein for the sake of clarity.

[0109] Note that the term “signaling”, as used herein, may alternatively be referred to as control signaling, control message, control information, or message for simplicity. Signaling between a base station (such as the TRP 170a, 170b, 172) and a UE or sensing device (such as ED 110), or signaling between different UEs or sensing devices (such as between ED 110a and ED 110b) may be carried in physical layer signaling (also called dynamic signaling), which is transmitted in a physical layer control channel. For DL, the physical layer signaling may be known as downlink control information (DCI) which is transmitted in a physical downlink control channel (PDCCH). For UL, the physical layer signaling may be known as uplink control information (UCI) which is transmitted in a physical uplink control channel (PUCCH). For SL, signaling between different UEs or sensing devices (such as between ED 110a and ED 110b) may be known as SL control information (SCI) which is transmitted in a physical sidelink control channel (PSCCH). Signaling may be carried in a higher layer (such as higher than physical layer) signaling, which is transmitted in a physical layer data channel, such as in a physical downlink shared channel (PDSCH) for downlink signaling, in a physical uplink shared channel (PUSCH) for uplink signaling, and in a physical sidelink shared channel (PSSCH) for SL signaling. Higher layer signaling may also be called static signaling, or semi-static signaling. The higher layer signaling may include radio resource control (RRC) protocol signaling or media access control - control element (MAC-CE) signaling. Signaling may be included in a combination of physical layer signaling and higher layer signaling. It is noted that in the present disclosure, “information”, when different from “message”, may be carried within a single message, or may be carried in multiple separate messages.

[0110] FIG. 4 illustrates an example apparatus 410 in accordance with some embodiments of the present disclosure. The apparatus 410 may be a communication device or an apparatus implemented in a communication device such as the ED 110 or the TRPs 170a, 170b, 172. For example, the apparatus 410 implemented in an ED may be an integrated circuit, which in some instances may be referred to as a chip, a modem, a modem chip, a baseband chip, or a baseband processor. In some implementations, one or more integrated circuits can be packaged into a system- on-chip, a system-in-package, or a multi-chip module. The apparatus 410 can include one or more integrated circuits and other discrete components. In some implementations, the apparatus 410 may be a module within the ED 110, or within the apparatus 310. In some implementations, the apparatus 410 may be a module within one of the TRPs 170a, 170b, 172, or the apparatus 320.

[0111] In an example, the apparatus 410 may include one or more processors 411, and an interface circuit 412. The apparatus 410 may further include a memory 413. The one or more processors 411 are configured to process signals and execute one or more communication protocols. The memory 413 is configured to store at least a part of corresponding computer program instructions and / or data. In an example, the one or more processors 411 execute the computer program instructions stored in the memory 413 to implement related operations (for example, inputting, outputting, receiving, and transmitting) in the method embodiments disclosed herein. In some implementations, the memory 413 being configured to store the corresponding computer program instructions and / or data may mean that the memory 413 is configured to store all of the corresponding computer program instructions and / or data for execution by the one or more processors 411. In some implementations, the memory 413 being configured to store the corresponding computer program instructions and / or data may mean that the memory 413 is configured to store a part of the corresponding computer program instructions and / or data. For example, the part of the corresponding computer program instructions and / or data may include computer program instructions and / or data that need to be currently executed by the one or more processors 411. Thus, the memory 413 may store different parts of computer program instructions and / or data for a plurality of times for the one or more processors 411 to perform related operations in the method embodiments disclosed herein. As a communication interface, the interface circuit 412 is configured to implement communication with another component. For example, the interface circuit 412 may communicate a signal with another apparatus or system, such as a radio frequency processing apparatus or another processor. The signal may include or carry information intended as a payload, such as user data, control information, etc. The signal may also include or carry information useful to a receiver, but not necessarily as a payload, such as a pilot signal or reference signal. Communicating the signal may include transmitting the signal to another component or device. Communicating the signal may additionally or alternatively include receiving the signal from another component or device. Transmitting the signal may include outputting the signal to a component or device that is directly or indirectly coupled to the interface circuit 412. Receiving the signal may include inputting or obtaining the signal from a component or device that is directly or indirectly coupled to the interface circuit 412. Optionally, to reduce a load of the one or more processors, a baseband signal processing circuit 414 may also be also provided to implement processing of at least a part of baseband signals, including signal demodulation, modulation, encoding, decoding, or the like.

[0112] The apparatus 410 may be the processor 210 (or 260) within the apparatus 310 (or 320) in some scenarios, or may be included within the processor 210 (or 260) within the apparatus 310 (or 320) in some scenarios. The apparatus 410 may be a baseband chip or may include a baseband chip. In some implementations, the apparatus 410 may be independently packaged into a chip. In some implementations, the apparatus 310 (or 320) includes different types of chips. The apparatus 410 may be packaged into a processor chip (for example, an SoC chip or an SIP chip) with the different types of chips. In some implementations, the apparatus 410 may be packaged into a chip with some or all of circuits of a radio frequency processing system that may further be included in the apparatus 310 (or 320).

[0113] FIG. 5 illustrates an example apparatus 510 in accordance with some implementations of the present disclosure. The apparatus 510 may include modules or units configured to implement methods and / or implementations described herein. In some implementations, the apparatus 510 includes a processing unit 512 and a communication unit 513. For example, the apparatus 510 may further include a storage unit 511 configured to store apparatus program code (or instructions) and / or data.

[0114] The apparatus 510 may be an ED side apparatus, for example, an ED or a module in an ED, or a circuit or a chip responsible for a communication function in an ED. In some implementations, the apparatus 510 may be the apparatus 310. The processing unit 512 may be the processor 210. The communication unit 513 may include a receiving unit and / or a transmitting unit. The receiving unit and / or the transmitting unit may be the transmitter 201 and / or the receiver 203 respectively. The storage unit 511 may be the memory 208.

[0115] The apparatus 510 may be a base station side apparatus, for example, a base station or a module in a base station, or a circuit or a chip responsible for a communication function in a base station. In some implementations, the apparatus 510 may be the apparatus 320. The processing unit 512 may be the processor 260 (the scheduler 253 may also be included). The communication unit 513 may include a receiving unit and / or a transmitting unit. The receiving unit and / or the transmitting unit may be the transmitter 252 and / or the receiver 254 respectively. The storage unit 511 may be the memory 258.

[0116] In some implementations, when the apparatus 510 is an ED 110 or a module in an ED 110, a function of the apparatus 510 may be implemented by one or more processors. For example, the processor may include a modem chip, or a system on chip (SoC) chip or an SIP chip that includes a modem core. A function of the communication unit 513 may be implemented by a transceiver circuit.

[0117] In some implementations, when the apparatus 510 is a circuit or a chip that is responsible for a communication function in an ED 110, such as a modem chip, a system on chip (SoC) chip or an SIP chip that includes a modem core, a function of the processing unit 512 may be implemented by a circuit system within the chip which includes one or more processors. A function of the communication unit 513 may be implemented by an interface circuit or a data transceiver circuit on the chip.

[0118] It may be understood that the units in the apparatus 510 may be logical or functional. Each function may correspond to one functional unit, or two or more functions may be integrated into a single functional unit. In actual implementation, all or some of the units may be integrated into a single physical entity, or may be distributed across different physical entities. In addition, the functional units may be implemented in the form of hardware, software, or a combination of hardware and software. Whether a function is implemented in the form of hardware or software depends on particular applications and design constraint conditions of the technical solutions. A person skilled in the art may use different methods to implement the described functions for specific applications, but it should not be considered that the implementation goes beyond the scope of this disclosure.

[0119] In an example, a functional unit in any one of the apparatuses may be configured as one or more integrated circuits for implementing the methods disclosed herein, for example, as one or more application-specific integrated circuits (ASICs), one or more central processing units (CPUs), one or more microprocessors or microprocessor units (MPUs), one or more microcontrollers or microcontroller units (MCUs), one or more digital signal processors (DSPs), one or more field programmable gate arrays (FPGAs), or a combination of these.

[0120] In an example, the storage unit 511 may include a random access memory (RAM), a flash memoiy, a readonly memory (ROM), a programmable read-only memoiy (PROM), an electrically erasable programmable readonly memory (EEPROM), and / or a register.

[0121] A processor may be referred to as a processor system, an application processor, a baseband processor, a processor circuit, or a processor core. The processor may include one or a combination of one or more central processing units (CPUs), one or more digital signal processors (DSPs), one or more microprocessors or microprocessor units (MPUs), one or more microcontrollers or microcontroller units (MCUs), one or more graphics processing units (GPUs), one or more field programmable gate arrays (FPGAs), one or more artificial intelligence (Al) processors, or one or more neural network processing units (NPUs).

[0122] Memory or a storage unit may include one or more of the following storage media: a random access memory (RAM), a static random access memory (static RAM, SRAM), a dynamic random access memory (dynamic RAM, DRAM), a phase-change memory (PCM), a resistive random access memory (resistive RAM, ReRAM), a magnetoresistive random access memoiy (magneto-resistive RAM, MRAM), a ferroelectric random access memory (ferroelectric RAM, FRAM), a cache, a register, a read-only memory (ROM), a flash memory, an erasable programmable read-only memory (erasable programmable ROM, EPROM), a hard disk, and the like. In an example, computer program instructions used to execute embodiments may be stored in a non-volatile memory, for example, at least a part of a memory or storage unit (for example, one or more of a ROM, a flash memory, an EPROM, or a hard disk). When a terminal runs, a part or all of corresponding computer program instructions may be loaded to a memory that has a higher transmission speed with the processor, for example, at least a part of a memoiy or a storage unit (for example, one or more of a RAM, an SRAM, a DRAM, a PCM, a RERAM, an MRAM, a FRAM, a cache, or a register), so that the processor executes the computer program instructions to perform the steps in the method embodiments disclosed herein.

[0123] Example concepts of some terms used herein are illustrated below.

[0124] Coprime integers: in number theory, two integers a and b are coprime, relatively prime or mutually prime if the only positive integer that is a divisor of both of them is 1. Comb-coprime combs: invented nonregular comb based on regular comb, inside which apply sampling created as concatenated coprime sequences (steps of sequences are coprime numbers).

[0125] Coprime comb sampling: sampling based on comb-coprime comb.

[0126] Comb-coprime sequence: sequence of resource element indexes inside one OFDM symbol for pilot mapping generated by concatenating several sequences with coprime step values.

[0127] For channel estimation in uplink channel, as one example, sounding reference signals (SRSs) may be used, where SRSs are located in some OFDM symbols over the whole bandwidth of the channel with some regular combs. In conventional solutions for channel estimation, combs are used to minimize the number of resource elements (REs) for SRS mapping and channel estimation, and cyclic shift of SRS sequence is used to maximize the number of available sequences to increase the number of supported users. For example, two cases of comb2 SRS mapping to the resource grid for a single user equipment (UE) and two UEs are illustrated in FIG. 6. Here comb2 means the comb value equals to two, that is, a distance between starting positions of two adjacent REs carrying the SRS on the same symbol is two REs (that is, one RE is between two adjacent REs carrying the SRSs on the same symbol, and actually one white block between two adjacent REs may be for other use). The term “comb” throughout the text will be of the same meaning unless otherwise defined. Regular transmission combs are generally applied in a wireless system. As shown in the right side of FIG. 6, in the case of comb2, it is possible to multiplex maximum 2 SRSs in one OFDM symbol. Without considering cyclic shift, it means that maximum two users can be served in one OFDM symbol.

[0128] A chosen transmission comb depends on the wireless channel (simply put, channel) characteristic. In general, a length of a comb window should be larger than a channel impulse response (CIR) length. Sparse measurements may be performed by a sparse sampling matrix. The sparse sampling matrix is P e CN x 1with K positions equal to 1 and (N - K) positions equal to 0, where N and K are integers greater than 1. Sparse measured frequency channel Hsmay be rewritten from full channel matrix H and the sparse sampling matrix as: Hs= P O H => FH• Hs— FH■ P) ® (FH• H) = wp© h, where h represents channel response in time domain. If a large comb is used, it may introduce non-controllable channel estimation interference.

[0129] To elaborate the interference, FIGS. 7A to 7C illustrate possible outputting results for different sampling patterns. Here, a sampling pattern may refer to a pattern with positions of reference signals for channel estimation being 1 and other positions being 0, since the transmission of the reference signals on the allocated REs would be like sampling of the allocated channels. FIGS. 7A to 7C also illustrate channel impulse response (CIR) intersection depending on comb value and cyclic shift. In FIGS. 7A to 7C, x-axis represents time, and y-axis represents CIR magnitude. As shown in FIG. 7A, in case of comb4, there is no intersection, and such sampling may lead to good channel estimation. However, if a comb value becomes larger, the distance in the time domain that can be distinguished by the system may become smaller. As shown in FIG. 7B, in case of comb8, there is an intersection which reflects self-interference (i.e., interference between different elements of CIR on a same symbol sent to a particular user), and such sampling may lead to poor channel estimation. If cyclic shift (CS) is used on the basis of FIG. 7A, the distance in the time domain that can be distinguished by the system would become even smaller, as shown in FIG. 7C, in case of comb4 and CS=2, there is also an intersection which reflects inter- interference (i.e. interference between different users), and such sampling may also lead to poor channel estimation. It can be seen that the CIR intersection depends on a comb value and a cyclic shift, which may be determined based on wireless channel characteristic. In addition, since CIR has a sparse structure (that is, non-zero elements in CIR are sparse), compressive sensing approaches can be used to restore CIR with smaller number of REs.

[0130] However, in conventional solutions for channel estimation, time delays of the channel may not be estimated accurately or efficiently, resulting in inaccuracy in channel estimation. In addition, regular transmission combs in frequency are used for mapping SRS, resulting in high mapping density.

[0131] In view of any of the above technical problems, embodiments of the present disclosure propose some solutions for channel estimation. The objective of the embodiments of the present disclosure is to improve the utilization of the resources for transmitting the reference signal(s) in channel estimation, and to improve the accuracy of channel estimation.

[0132] Various embodiments of the present disclosure will be described below by way of example. Methods of the embodiments of the present disclosure may be performed by a transmitting device and a receiving device. The transmitting device and the receiving device may be different devices in different communication scenarios. For example, in downlink communication, the transmitting device may be a network device such as BS, and the receiving device may be a terminal device such as UE. In uplink communication, the transmitting device may be a terminal device such as UE, and the receiving device may be a network device such as BS. The following embodiments will be illustrated by taking an example where the transmitting device is a UE and the receiving device is a BS.

[0133] Reference is now made to FIG. 8, which illustrates a device interaction diagram in accordance with some embodiments of the present disclosure. The device interaction involves a UE and a BS.

[0134] In step 801, the UE determines a first sampling sequence and a second sampling sequence. The first sampling sequence is for indicating first frequency domain resources, the second sampling sequence is for indicating second frequency domain resources. The first sampling sequence and the second sampling sequence are coprime sequences. The first frequency domain resources may be a first set of subcarriers, and the second frequency domain resources may be a second set of subcarriers. The first frequency domain resources and the second frequency domain resources may not be overlapped, or may be overlapped at a small quantity of frequency domain resources (e.g. at a sub-carrier).

[0135] In step 802, the UE transmits a first reference signal on the first frequency domain resources based on the first sampling sequence. Accordingly, the BS receives the first reference signal. The first sampling sequence may indicate position of the first reference signal. For example, the first sampling sequence indicates indices of subcarriers for transmitting the first reference signal.

[0136] In step 803, the UE transmits a second reference signal on the second frequency domain resources based on the second sampling sequence. Accordingly, the BS receives the second reference signal. The second sampling sequence may indicate position of the second reference signal. For example, the second sampling sequence indicates indices of sub-carriers for transmitting the second reference signal. The first reference signal and the second reference signal may be sounding reference signal (SRS) or demodulation reference signal (DMRS), and the first reference signal and the second reference signal are not limited thereto.

[0137] It is noted that step 802 may be performed before or after step 803, or may be performed at the same time with step 803, which is not limited in the present disclosure.

[0138] In step 804, the BS obtains first channel information and second channel information by performing channel measurements using the first reference signal and the second reference signal, respectively. The first channel information may include a channel matrix of a first channel estimated by the first reference signal. The second channel information may include a channel matrix of a second channel estimated by the second reference signal. The first channel and the second channel may each be a subset of a full channel in a MIMO system. The full channel in the MIMO system may include all channels between the BS and the UE.

[0139] In step 805, the BS obtains time delays estimation of a full channel based on the first channel information and the second channel information.

[0140] In step 806, the BS obtains third channel information based on the time delays estimation. The third channel information includes full channel information. The full channel information may include frequency response information (i.e. first frequency response information) of the full channel or channel matrix of the full channel.

[0141] In such case, the UE transmits reference signals in given frequency domain resources based on coprime sequences. Since the first sampling sequence and the second sampling sequence are coprime sequences, the first frequency domain resources and the second frequency domain resources may be sparsely distributed on given frequency domain resources, which means that the first frequency domain resources and the second frequency domain resources may be limited within a certain number of frequency domain resources, and the remaining frequency domain resources may be used for transmitting reference signals to other users, thereby improving the utilization of the resources. In addition, the BS performs channel measurement and obtains time delays estimation of a full channel. Based on the comb coprime sequences, larger number of time delays may be obtained, thereby improving the accuracy of channel estimation.

[0142] For example, the first sampling sequence is a set of sub-carrier indices which is represented as The second sampling sequence is a set of sub-carrier indices which is represented as Q2. The UE transmits the first reference signal on the sub-carriers based on Qr. Accordingly, the BS receives the first reference signal. The UE transmits the second reference signal on the sub-carriers based on Q2. Accordingly, the BS receives the second reference signal. The BS then performs channel measurements with all BS antennas using the first reference signal and the second reference signal, respectively. In this way, the BS obtains the first channel information including a partial channel matrix H1= H (Qt, : ) , and the BS obtains the second channel information including a partial channel matrix H2= H(Q2, : ), where H E CNSC*NRX represents full channel matrix, Nscrepresents number of subcarriers in band, NRXrepresents number of antenna elements in receiving array (i.e. number of BS antennas in uplink measurement). The BS further estimates, based on Hrand H2, time delays of the full channel to obtain frequency response of the full channel. In some embodiments, step 805 of obtaining time delays of a full channel based on the first channel information and the second channel information includes: obtaining a covariance matrix based on the first channel information and the second channel information, obtaining a first vector by vectorizing the covariance matrix, and obtaining the time delays based on the first vector.

[0143] Based on the covariance matrix and the first vector, larger number of time delays may be obtained effectively.

[0144] The covariance matrix may be a submatrix of covariance matrix of the full channel.

[0145] The covariance matrix may be a multi-rank covariance matrix with rank close to the rank of the wireless channels. In wireless channels, covariance matrix for single antenna is of rank one. In such case, coprime sampling method may not be directly applicable to channel estimation of wireless channels. In some embodiments of the present disclosure, the BS obtains, based on the first channel information and the second channel information, multirank covariance matrix with rank close to the rank of the wireless channels, and makes comb coprime sampling applicable in channel estimation.

[0146] In the above example, the BS obtains a covariance matrix RQ by: where RQ E cl0ilxlb2l , Qris the first sampling sequence, Q2is the second sampling sequence, and R = HHHis Full covariance matrix.

[0147] In this way, the covariance matrix RQ is obtained by averaging over antenna elements of BS array. Alternatively, the BS may obtain the covariance matrix RQ by averaging over frequencies.

[0148] In a case where the number of receiving antenna elements is large enough, structure of the covariance matrix may be close to Toeplitz structure, which may be ideal for further processing. Full covariance matrix R = HHHapproximately has Toeplitz positive semidefinite structure and therefore may be represented in following form:

[0149] R ® SMSH, where columns of 5 are steering vectors. The matrix S may be represented as:

[0150] S' = [sTwhere s nk) satisfies: sk= [1k) exp(2m2AfTk) ... exp(2mNscAfTk)]T, where A / is subcarrier spacing, i is imaginary unit, are time delays to be estimated, M e Rank* Rank ;s a rea] diagonal matrix, and diagonal element mkkrepresent power of k-th time delay.

[0151] The BS may obtain a first vector by vectorizing the covariance matrix. In the above example, the BS may obtain a first vector VQ by vectorizing the covariance matrix RQ:

[0152] VQ= vec(RQ), where vec( ) represents matrix vectorization by concatenation of matrix column into single vector,

[0153] VQ ~ SQm, where m is a vector of diagonal elements of matrix M, m = [mnm22■ ■■mRankRank]T.

[0154] SQ = = )0S(Q2> '■ )L where o represents Khatri-Rao product (i.e. column wise Kronecker product).

[0155] Each element of matrix SQ is complex exponent and satisfies: where (qt— q2)prepresents the difference between elements of the QltQ2samplings corresponding to the p-th row of the matrix SQ, i is the imaginary unit, 1 < p < Nsc, and 1 < q < Rank.

[0156] In an implementation, the step of the BS obtaining the time delays estimation based on the first vector includes: obtaining a second vector by processing the first vector; and obtaining the time delays based on the second vector. Processing the first vector may help the BS to obtain or estimate the time delays efficiently.

[0157] Processing the first vector may be sorting the first vector in ascending order or descending order of differences between row index and column index of RQ elements.

[0158] In the above example, the BS obtains a second vector VQSby sorting the first vector VQ in ascending order.

[0159] In an implementation, the step of the BS obtaining the time delays estimation based on the second vector includes: obtaining the time delays based on the second vector using compressed sensing or least squares. In such case, larger number of time delays may be obtained.

[0160] The BS may obtain the time delays estimation by searching non-zero coefficients of the second vector representation in fixed dictionary using compressed sensing or least squares. In this way, the BS may obtain the time delays estimation efficiently. Alternatively, other parametric methods can also be used to estimate the time delays.

[0161] In the above example, the second vector VQSis represented as:

[0162] VQS ~ QSm'

[0163] Vector m and / or time delays estimation {r4— tRank} are obtained from compressive sensing problem of searching non-zero coefficients of the second vector VQSin third dictionary information.

[0164] The third dictionary information may include a third dictionary matrix. The third dictionary matrix may be obtained based on a first dictionary matrix in first dictionary information. The first dictionary matrix may be oversampled. In an example, the first dictionary matrix is a Fourier matrix. The Fourier matrix is the matrix of discrete Fourier transformation where each element of the Fourier matrix is a complex exponent. The third dictionary matrix may include a set of rows in the first dictionary matrix. The index of the set of rows in the first dictionaiy matrix may be obtained by calculating all possible differences between q1and q2, where q1G Q1(q26 Q2.

[0165] In an example, the first dictionary matrix is represented as D , and an (p, q)th element of this matrix is oversampling = 0 ... Nsc0 — 1, k = 1 ... Rank. In case of oversampled, size of the Fourier matrix is Nsc by NscO. In case of non-oversampled, size of the Fourier matrix is Nsc by Nsc. SQSmay be obtained by sorting SQ in ascending order.

[0166] In some embodiments, the BS further obtains coefficients estimation, and the BS obtains first dictionary information based on the time delays. The first dictionaiy information is for indicating steering vectors of the full channel. In such case, the BS obtains the third channel information based on the coefficients estimation and the first dictionary information. Based on the coefficients estimation, the BS may obtain the full channel information efficiently.

[0167] For example, first dictionary information is matrix S that is estimation of matrix S.

[0168] In such case, S includes dictionary columns with indexes corresponding to the time delays estimation from dictionary

[0169] In the above example, after obtaining the coefficients estimation x and the first dictionary information, the BS obtains h which is a frequency response (i.e., first frequency response) of the full channel, hf may be obtained by: hf = Sx. In this way, the full channel information is obtained by the BS.

[0170] In an implementation, the BS obtains second dictionary information for indicating steering vectors of channels in the full channel corresponding to the first sampling sequence and the second sampling sequence. The BS further obtains frequency response information (i.e. second frequency response information) for indicating frequency response (i.e. second frequency response) of the channels corresponding to the first sampling sequence and the second sampling sequence. In such case, the BS may obtain the coefficients estimation based on the second dictionary information and the frequency response information, and the coefficients estimation may be obtained effectively.

[0171] The second dictionary information and the second frequency response information may be obtained based on the first sampling sequence and the second sampling sequence. The second dictionary information is a set of S rows of the first dictionary, where the rows correspond to the measured subcarriers. Indices of the rows may each be an element in intersection of both samplings k e Q±U Q2The BS may obtain the coefficients estimation based on the relationship in which the value of the second frequency response equals to the production of multiplying the value of second dictionary information by the value of the coefficients estimation.

[0172] In the above example, the BS obtains the second dictionary information including a second dictionaiy S(Q1 U Q2, ) for indicating steering vectors of channels in the full channel corresponding to the first sampling sequence QI and the second sampling sequence Q2. The BS further obtains frequency response hQon receiving antennas or receiving antenna beams at frequencies indicated by the first sampling sequence QI and the second sampling sequence Q2, and hQis represented as hQ= hffXh U Q2), where hf *) represents frequency response of the channel.

[0173] Since hQ, S Q1 U Q2, : ), and the coefficients estimation x satisfy the relationship hQ= S((?l U Q2, )x, x can be obtained by LS or CS method, which is not limited in the present disclosure.

[0174] In some embodiments, the first sampling sequence has a step of C * Px, and the second sampling sequence has a step of C * P2, where C is a regular transmission comb value, Ptis a first coprime step value, P2is a second coprime step value, C, Ptand P2are positive integers, and Pris coprime to P2. In the above example, since Pris coprime to P2, Q U Q2which is the unity of the first sampling sequence and the second sampling sequence Q2may be comb-coprime sequence. Since U Q2is coprime sequence, the first frequency domain resources and the second frequency domain resources may be sparsely distributed on given frequency domain resources, thereby improving the utilization of the resources. In the above example, the first sampling sequence Qj satisfies Qj = Br: CPX: Eltwhere Bris the minimum of values of elements in the first sampling sequence Qr, where is the maximum of values of elements in the first sampling sequence Qt, and the second sampling sequence satisfies Q2= B2: CP2: E2, where B2is the minimum of values of elements in the second sampling sequence Q2. where E2is the maximum of values of elements in the second sampling sequence Q2.

[0175] BltEltB2, E2values are different for different ports to be measured. In this way, non- intersecting samplings QltQ2assigned to different ports in a single OFDM symbol may be provided. In other word, intersection between samplings for different ports may be avoided.

[0176] In some embodiments, a maximum of values of elements in the first sampling sequence is (2CP1P2— CP1+ 1), and a maximum of values of elements in the second sampling 'sequence is (CP-jP2— CP2+ 1). In this way, the first frequency domain resources and the second frequency domain resources may be limited within a certain number of frequency domain resources, thereby reducing the number of frequency domain resources for transmitting the first reference signal and the second reference signal.

[0177] In some embodiments, a number of elements in the first sampling sequence is (2P2— 1) or approximately(2P2- 1), and a number of elements in the second sampling sequence is (PA— 1) or approximately (Pi — 1). fri such case, elements in the first sampling sequence may be determined based on the minimum of values of elements in the first sampling sequence, the step of the first sampling sequence, and the number of elements in the first sampling sequence. Elements in the second sampling sequence may be determined similarly.

[0178] In some embodiments, Prand P2are determined based on a quantity of resource units in the frequency domain resources. Pxand P2may satisfy: 1) • CP1+ C, the quantity of the resource units in the frequency domain resources. Approximately, Q2) « Nsc.

[0179] ( CPAP2- CP2) is approximately equal which is half of the number of the sub-carries, and (2CP1P2— CPj) is approximately equal to Nscwhich is the number of the sub-carries. In this way, the first reference signal may be distributed over half of the sub-carriers, and the second reference signal may be distributed over the sub-carriers, thereby reducing the number of frequency domain resources for transmitting the first reference signal and the second reference signal, and channel estimation may be performed effectively.

[0180] In some embodiments, the first frequency domain resources comprise multiple first frequency units, and indices of the multiple first frequency units are determined based on a starting position of the multiple first frequency units, the regular transmission comb value, and the first coprime step value Pr. The second frequency domain resources comprise multiple second frequency units, and indices of the multiple second frequency units are determined based on a starting position of the multiple second frequency units, the regular transmission comb value , and the second coprime step value P2.

[0181] In this way, indices of the multiple first frequency units and / or indices of the multiple second frequency units may be determined.

[0182] For example, the first frequency domain resources comprise multiple first frequency units. Index of each first frequency unit may be determined based on the starting position of the multiple first frequency units, the regular transmission comb value, and the first coprime step value P±.

[0183] In some embodiments, the BS further transmits first information to the UE. The first information may indicate at least one of: time domain resources for transmitting the first reference signal and / or the second reference signal, quantity of time domain units in the time domain resources for transmitting the first reference signal and / or the second reference signal, a starting position of the first frequency domain resources and / or a starting positing of the second frequency domain resources, the regular transmission comb value C, the first coprime step value Pr, the second coprime step value P2, or an index of the first information associated to the first reference signal and / or the second signal. Accordingly, the UE receives the first information and determines the first sampling sequence and the second sampling sequence based on the first information.

[0184] The first information may be carried in a parameter set. The BS may transmit the parameter set to the UE. As shown in FIG. 9, the BS may transmit the A-th parameter set to the #-th UE, where the parameter set may include parameters indicating a starting position of the first frequency domain resources, quantity of time domain units for transmitting the first reference signal, a value of a regular transmission comb, a value of the step of the first sampling sequence and / or a value of the step of the second sampling sequence, starting position in frequency domain of the first sampling sequence and / or the second sampling sequence, time domain resources for transmitting the first reference signal and / or the second reference signal, or an index of parameters for the UE.

[0185] It should be noted that, the listed parameters may not all transmitted to UE. Some parameters can be predefined for UE, or some parameters may be determined based on other parameters. In this case, the UE may not receive corresponding parameters from the BS.

[0186] In an implementation, the parameter set includes a parameter indicating time domain resources for transmitting the first reference signal and / or the second reference signal. In such case, the parameter may indicate starting position(s) of the time domain resources for transmitting the first reference signal and / or the second reference signal. For example, the first information includes a parameter NSymbStart#. NSymbStart# is an index of a first OFDM symbol which is the beginning of a symbol set. The symbol set includes multiple OFDM symbols inside one slot for SRS transmission. NSymbStart# c Nlxl.

[0187] In the multiple OFDM symbols, symbols 8 to 13 may be with a normal cyclic shift, symbols 8 to 11 may be with an extended cyclic shift.

[0188] In an implementation, the parameter set includes a parameter indicating quantity of time domain units in the time domain resources for transmitting the first reference signal and / or the second reference signal.

[0189] For example, the first information includes a parameter NSymb#. NSymb# is the total number of OFDM symbols in a slot for SRS transmission. NSymb# c Nlxl. The OFDM symbols may be consecutive symbols in a slot.

[0190] The OFDM symbols may be with a normal cyclic shift in a case of NSymb# from 0 to 6, and may be with an extended cyclic shift in a case of NSymb# from 0 to 4. In an implementation, the parameter set includes a parameter indicating time domain resources for transmitting the first reference signal and / or the second reference signal.

[0191] For example, the first information includes a parameter CoPrimeSymb. CoPrimeSymb is an array of OFDM symbol indices inside which NSymb# symbols for pilot transmission are allocated. CoPrimeSymb e N2xM, where M is the maximum number of UEs served simultaneously in the given cell. Each column in CoPrimeSymb is the vector including two elements where the first element indicates a first symbol index for transmitting the first reference signal, and the second element indicates a second symbol index for transmitting the second reference signal.

[0192] In an implementation, the parameter set includes a parameter indicating the regular transmission comb value C.

[0193] For example, the first information includes a parameter Ncomb# which is a regular transmission comb value. Ncomb# e Nlxl. Ncomb# may equal to 2, 8, or 16, which correspond to comb2, comb8, and combl6, respectively.

[0194] In an implementation, the parameter set includes a parameter indicating the first coprime step value Prand / or the second coprime step value P2. In such case, value of the step of the first sampling sequence and / or a value of the step of the second sampling sequence may be obtained.

[0195] For example, the first information includes a parameter CoPrime which is a set of coprime steps (i.e. the foregoing mentioned coprime step values). The parameter Coprime may be in a form of a vector. In an example, CoPrime e Nlx2

[0196] In an implementation, the parameter set includes a parameter indicating a starting position of the first frequency domain resources and / or a starting positing of the second frequency domain resources.

[0197] In one example, the first information includes a parameter CoprimeOffset. CoprimeOffset indicates BTwhich is the index of the first sub-carrier in the first sampling sequence In addition, CoprimeOffset also indicates B2which is the index of the first sub-carrier in the second sampling sequence Q2. Here, the first sub-carrier refers to the sub-carrier at the starting position of the multiple sub-carriers for transmitting the reference signal.

[0198] In another example, the first information includes a parameter CoprimeOffset, and CoprimeOffset is an array of RE offsets for each coprime sequence from the beginning on the allocated bandwidth. In such case, CoPrimeOffset c N2xM, where M is the maximum number of UEs served simultaneously in the given cell. Each column in CoPrimeOffset is a vector with RE indices for the first (i.e. starting or beginning) positions of coprime sequences.

[0199] In an implementation, the parameter set includes a parameter indicating an index of parameters for the UE. The index or ID is for indicating a parameter corresponding to a given UE.

[0200] For example, the first information includes a parameter which is an index of column inside CoPrimeOffset and CoPrimeSymb for SRS mapping of A-th UE (i.e., any UE from the M UEs).

[0201] In some embodiments, the BS may transmit M parameter sets to M UEs, where M is the maximum number of served users (UEs) in the given cell. The UE mentioned above belongs to the M UEs. One parameter set may correspond to one UE.

[0202] Embodiments of the present disclosure may be based on the fact of Q12has partially continuous range, where Q12is a set including differences between elements of first and second coprime samplings. Q12= e Qi> <?2eQz) is set of difference sampling, where qr— q2is the difference between q1and q2, <7i is an element in Q±, and q2is an element in Q2.

[0203] FIGS. 10A and 10B illustrate properties of sorted set <?12. In the case where vector c and time delays {TI —TRank} are found from compressive sensing, set Q12is used to form sensing matrix of compressed sensing problem, where set (?12is the set of rows of oversampled in general case of Fourier matrix sampling. sort(Q12) is formed by sorting Q12in ascending order. In FIG. 10A, x-axis is index of(?12elements, y-axis is value of Q12 elements. As seen from FIG. 10A, a maximum difference between elements of Q12is higher than Nsc, which may help improve the accuracy of channel estimation.

[0204] In FIG. 10B, x-axis is index of Q12 elements, and diff(sort(Q12y) in y-axis is the difference between neighboring elements in Q12. As seen from FIG. 10B, a length of continuous range with difference ones is (PA■ P2+ Pi + P2— 1) which approximately equals to Nsc / 2. In this way, the accuracy of channel estimation may be further improved.

[0205] FIG. 11 illustrates an absolute value of the first column of Gram matrix of the third dictionary matrix. The Gram matrix G may be obtained by: G — D3D3, where D3is the third dictionary matrix. The quality of Q12may be numerically characterized by coherence values (i.e., maximum absolute values of non-diagonal element in the Gram matrix). In FIG. 11, x-axis is index of the rows in the Gram matrix, and y-axis is magnitude of elements in the Gram matrix. As shown in FIG. 11 , in case of no oversampling, based on the Toeplitz structure of Gram matrix, the absolute value of the first column of Gram matrix is close to the ideal case where the values of magnitude of the elements are 1, 0, 0, ...0. In this case, the third dictionary (i.e. sampled Fourier matrix) is applicable. Elements in the sampled Fourier matrix may be set of rows indexes from Q12.

[0206] The following is an example of determining indices of resource elements for SRS sequence mapping. In this example, all subcarriers inside a given OFDM symbol are divided into a subarray in accordance with a given parameter Ncomb#.

[0207] The following is an example where NSymbStart# = 9 (i.e., the tenth OFDM symbols in a slot), NSyrnb# = 1 (i.e. the comb-coprime comb will be done inside one OFDM symbol), CoPrimeSymb = [1 l]r, Ncomb# = 8 (i.e. comb-coprime comb will be generated based on regular comb8. Comb8 splits range of all subcarriers inside one symbol to the 8 subarrays with step 8, i.e. 8 x Comb8 arrays), CoPrime =

[1112] , CoprimeOffset =

[0110] , NCoPrimeComb# = 1.

[0208] Indices in the first sampling sequence for the A-th UE are determined by:

[0209] Qcombi(k>f)=CoPrimeOffset(l, fc) + P1* Ncomb# * f , where f = 0,1, 2, 3 fc) ~ 1 , where

[0210] / Max(t fc) is natural number such that QCombi(k,fMAX(l, k)) < N(l, k), QCombi(k,fMAX(.l, k') + 1) > N(l, / c), where N(l, k) = min(CoPrimeOffset(l, k) + Ncomb# * (2 * CoPrime(l) * CoPrime(2) — CoPrime(l)), Nsc).

[0211] In this case, sub-carriers indicated by the first sampling sequence Qrare distributed over the fall band.

[0212] Indices in the second sampling sequence Q2for the A-th UE are determined by:

[0213] Qcombz(k>f) = CoPrimeOffset(2, fc) + P2* Ncomb# * f, In a case where CoPrimeOffset(2, k) then / = 0, 1, 2 ... fMAX(2, k) , where fMAX(2, k) is natural number such that QComb2(k,fMAX(2, k')) < N(2, k) , Qcomb2(k,fMAX(2, k) + 1) > N(2, k) , where N(2, k) = min(CoPrimeOffset(2, k) + Ncomb# * (CoPrime(l) * CoPrime(2) - CoPrime(2)), iVsc / 2).

[0214] In this case, sub-carriers indicated by the first sampling sequence Q2are distributed over half of the full band.

[0215] In a case where CoPrimeOffset(2, k) , then 0 < f < fMAX(2, k) , is natural number such that Qcomb2^,fMAX(2, k)>) < N(2, k) , Qcomb2^,fMAX(2lk) + 1) > N(2, k) , where N(2, k) = min(CoPrime0ffset(2, k) + Ncomb# * (CoPrime(l) * CoPrime(2) - CoPrime(2)), Nsc) .

[0216] In this case, sub-carriers indicated by the second sampling sequence Q2are distributed over another half of the full band.

[0217] In an implementation, each offset indicated by the parameter CoPrimeOffset is an absolute offset which is the sum of two parts:

[0218] CoPrimeOffset where CoPrimeOffset(i, k) is the parameter CoPrimeOffset for the k-th UE, C (i, k) is regular Comb index, 1 < C(i, k) < NComb# (because regular combs begin with 1 ... NComb#);

[0219] L(i, k) represents...,

[0220] H is an indicator of the half of the frequency band used by the second sampling, and value of H equals to 0 or 1. The value of H equals to 0 refers to that the reference signal or the sampling is distributed over a first half of the frequency band, and the value of H equals to 1 refers to that the reference signal or the sampling is distributed over a second half of the frequency band. For example, for second sampling, H = 0.

[0221] In addition, Prand P2are coprime numbers that satisfy the following condition: — « (ZP^ — Pi).

[0222] The slot may be of 5G NR slot structure. The above example of comb-coprime comb is done inside one OFDM symbol. In a case where comb-coprime comb is done inside more than one OFDM symbol, the procedure inside each additional symbol may refer to the procedure in the one OFDM symbol.

[0223] Two samplings of one user can be assigned to one OFDM symbol or two different OFDM symbols. FIG. 12 illustrates an example where both samplings are assigned into one OFDM symbol. In this example, Ncomb# = 8, Pi, P2= 8,9. Ports 1...8 may be antenna ports of UE1 ... UE8, and each of UE1 ... UE8 has a single antenna, for example. The first frequency domain resources indicated by first sampling for Port 1 ... 8 marked with “Comb8#l” is distributed over the subcarriers in a symbol, and the step of the first sampling sequence for Port 1 ... 8 equals to Ncomb# x p1= 8 x 8 = 64. The second RS “Comb8#2, H = 0” is distributed over half of the subcarriers in the same symbol, and the step of the second sampling Ncomb# x p2= 8 x 9 = 72. As described above, H = 0 refers to that the RS is distributed over a first half of the subcarriers the same symbol, and H = 1 refers to that the RS is distributed over a second half of the subcarriers the same symbol. In addition, the white part may be used for first frequency domain resources of a UE with second frequency domain resources in other OFDM symbol.

[0224] FIG. 13 illustrates an example where two samplings are assigned into two OFDM symbols. In this example, Ncomb# = 8, P P2 = 8,9. Ports 1...8 may be antenna ports of UE1 ... UE8, and each ofUEl ... UE8 has a single antenna. The first frequency domain resources indicated by the first sampling for Port 1 ... 8 marked with “Comb8# 1 ” is distributed over the subcarriers in a symbol (i.e. symbol 1), and the step of the first sampling sequence for Port 1 ... 8 equals to Ncomb# * P = 8 x 8 = 64. The second RS marked with “Comb8#2, H = 0” is distributed over half of the subcarriers in another symbol (i.e. symbol 2), and the step of the second sampling sequence equals to Ncomb# x P2= 8 x 9 = 72. In addition, the white part may be used by another UE’s first frequency domain resources and second frequency domain resources.

[0225] FIG. 14 illustrates some simulation results in accordance with some embodiments of the present disclosure. The simulation is performed to demonstrate the advantage of two comb-coprime sampling compared to regular transmission comb. The results were obtained at realizations of 308.901 UMa NLOS channels for multi user (MU) case. For the comparison, the cumulative density function (CDF) of cell throughput may be calculated for different types of frequency sampling with different SNR: proposed two comb-coprime sampling with OdB SNR, regular comb4 with high SNR, regular comb4 with low SNR, and regular comb36 with OdB SNR. The parameters for simulations are in the following Table.

[0226] Table 1

[0227] In the simulation, the SNR is calculated in dependence of number of subcarriers by: SNRN[dB] = SNRM[dB] + log10M - log10N, where TV, M are numbers of subcarriers involved different measurement procedures. For example M = I <2i I + I <221 for Coprime Based measurement, N - Nsc / Comb for regular Comb based measurement. This formula provides equal total power, while number of subcarriers involved in the measurement may be changed.

[0228] In the simulation, comparison was made between the proposed solution with OdB SNR, comb4 with 3 OdB SNR, comb4 with -8dB SNR, and comb36 with OdB SNR. As shown in FIG. 14, comb4 with 30dB SNR make the quality of channel estimation and spectral efficiency close to the ideal value.

[0229] Comb4 with -8dB SNR correspond to the same total transmitted power for proposed method with 0 dB SNR. In case of comb36 with OdB SNR, number of subcarriers and the SMR are the same as the proposed solution. However, comb36 with OdB SNR case with regular structure may not allow to get good channel estimation and spectral efficiency.

[0230] It is noted that the use of the values given in the simulation parameters is not a limitation. The parameters of number of subcarriers, number of BS antennas, number of UEs in group, the number of OFDM symbols, the steps of coprime sequences can be varied. The subcarrier spacing and regular transmission comb values can vary also but the regular comb value should change according the CIR length for the current subcarrier spacing.

[0231] The proposed solutions can be implemented in uplink channel estimation or downlink channel estimation, which is not limited in the present disclosure.

[0232] In some embodiments, the proposed sparse measurement procedure uses coprime sampling technique inside regular comb (dense mapping of "pseudo-random" samplings), thereby decreasing the length of pilot sequence for one UE and decrease the number of resource elements (REs) per antenna used in channel estimation procedure. Channel estimation may be performed on small number of samples compared with using regular transmission comb.

[0233] The proposed solutions may require IComb times less samples compared with conventional solutions. The density of pilot sequence mapping on the resource grid for multi user case may be increased, thereby increasing the number of simultaneously served users. Taps of channel response may be estimated with small number of samples. In this way, huge number of taps may be estimated potentially by the proposed solution. 2CP1P2 « P2® P, then P = Nsc / 2C, |<2i | + |<?21 ~ 3P = 2> ]Nsc / 2C i.e. inversely proportional to the square root of Comb.

[0234] The present disclosure encompasses various embodiments, including not only method embodiments, but also other embodiments such as apparatus embodiments and embodiments related to non-transitory computer readable storage media. Embodiments may incorporate, individually or in combinations, the features disclosed herein.

[0235] Although this disclosure refers to illustrative embodiments, this is not intended to be construed in a limiting sense. Various modifications and combinations of the illustrative embodiments, as well as other embodiments of the disclosure, will be apparent to persons skilled in the art upon reference to the description.

[0236] Features disclosed herein in the context of any particular embodiments may also or instead be implemented in other embodiments. Method embodiments, for example, may also or instead be implemented in apparatus, system, and / or computer program product embodiments. In addition, although embodiments are described primarily in the context of methods and apparatus, other implementations are also contemplated, as instructions stored on one or more non-transitory computer-readable media, for example. Such media could store programming or instructions to perform any of various methods consistent with the present disclosure.

[0237] Some embodiments of the present disclosure provide a computer-readable storage medium (e.g., a non- transitory computer-readable storage medium). The computer-readable storage medium has stored thereon program instructions that, when run on a network device / terminal device, cause the network device / terminal device to execute one or more steps of the method for beam management as described in any one of the above embodiments.

[0238] For example, the computer-readable storage medium includes, but is not limited to, a magnetic storage device (e.g., a hard disk, a floppy disk or a magnetic tape), an optical disk (e.g., a compact disk (CD), or a DVD), a smart card, and a flash memory device (e.g., an erasable programmable read-only memory (EPROM), a card, a stick or a key driver). Various computer-readable storage media described in the embodiments of the present disclosure may represent one or more devices and / or other machine-readable storage media, which are used for storing information. The term "computer-readable storage medium" may include, but is not limited to, wireless channels and various other media capable of storing, containing and / or carrying instructions and / or data.

[0239] Some embodiments of the present disclosure further provide a computer program product. The computer program product includes program instructions carried on a non-transitory computer-readable storage medium. When executed on a network device / terminal device, the computer program instructions cause the network device / terminal device to perform one or more steps of the method for data transmission as described in the above embodiments.

[0240] Beneficial effects of the computer-readable storage medium and the computer program product are the same as the beneficial effects of the method for data transmission as described in some of the above embodiments, and details will not be repeated here.

[0241] The foregoing descriptions are merely specific implementations of the present disclosure, but the protection scope of the present disclosure is not limited thereto. Any changes or replacements within the technical scope of the present disclosure shall be included in the protection scope of the present disclosure. Therefore, the protection scope of the present disclosure shall be subject to the protection scope of the claims.

[0242] In some aspects of the present disclosure, there is provided a computer program comprising instructions. The instructions, when executed by a processor, may cause the processor to implement a method of the present disclosure.

[0243] In some aspects of the present disclosure, there is provided an integrated circuit. The integrated circuit includes one or more logic circuits for executing the steps of the method for data transmission of the present disclosure.

[0244] In some aspects of the present disclosure, there is provided an apparatus comprising means (e.g., at least one processor) to implement a method of the present disclosure. The apparatus may be device (that is, a terminal device or a network device) or a module or component in the device. The at least one processor may execute instructions stored in a computer-readable medium to implement the method.

[0245] The apparatus may be a communication device or an apparatus implemented in a communication device. For example, the apparatus implemented in a communication device may be an integrated circuit, which in some contexts may be known by other colloquial names, such as chip, modem, modem chip, baseband chip, or baseband processor. In some implementations, one or more integrated circuits can be packaged into a system-on-chip, a system-in-package, or a multi-chip module. The apparatus may comprise one or more integrated circuits or comprise one or more integrated circuits and other discrete components.

[0246] It will be appreciated that any module, component, or device disclosed herein that executes instructions may include, or otherwise have access to, a non-transitory computer / processor readable storage medium or media for storage of information, such as computer / processor readable instructions, data structures, program modules and / or other data. A non-exhaustive list of examples of non-transitory computer / processor readable storage media includes magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, optical disks such as compact disc read-only memory (CD-ROM), digital video discs or digital versatile discs (i.e., DVDs), Blu-ray Disc™, or other optical storage, volatile and non-volatile, removable and non-removable media implemented in any method or technology, random-access memory (RAM), read-only memory (ROM), electrically erasable programmable read-only memory (EEPROM), flash memory or other memory technology. Any such non-transitory computer / processor storage media may be part of a device / apparatus or accessible or connectable thereto. Computer / processor readable / executable instructions to implement a method, an application or a module described herein may be stored or otherwise held by such non-transitory computer / processor readable storage media.

[0247] It could be noted that the message in the disclosure could be replaced with information, which may be carried in one single message, or be carried in more than one separate message.

[0248] The terms “apparatus” and “device” are used exchangeable.

[0249] In the present disclosure, the terms “a” or “an” are defined to mean “at least one”, that is, these terms do not exclude a plural number of items, unless stated otherwise.

[0250] In the present disclosure, terms such as “substantially”, “generally” and “about”, which modify a value, condition or characteristic of a feature of an example embodiment, should be understood to mean that the value, condition or characteristic is defined within tolerances that are acceptable for the proper operation of the example embodiment for its intended application.

[0251] In the present disclosure, unless stated otherwise, the terms “connected” and “coupled”, and derivatives and variants thereof, refer herein to any structural or functional connection or coupling, either direct or indirect, between two or more elements. For example, the connection or coupling between the elements can be acoustical, mechanical, optical, electrical, thermal, logical, or any combinations thereof.

[0252] In the present disclosure, expressions such as “match”, “matching” and “matched”, including variants and derivatives thereof, are intended to refer herein to a condition in which two or more elements are either the same or within some predetermined tolerance of each other. That is, these terms are meant to encompass not only “exactly” or “identically” matching the two elements but also “substantially”, “approximately” or “subjectively” matching the two or more elements, as well as providing a higher or best match among a plurality of matching possibilities.

[0253] In the present disclosure, the expression “based on” is intended to mean “based at least partly on”, that is, this expression can mean “based solely on” or “based partially on”, and so should not be interpreted in a limited manner. More particularly, the expression “based on” could also be understood as meaning “depending on”, “representative of’, “indicative of’, “associated with” or similar expressions.

[0254] In the present disclosure, the terms "system" and "network" may be used interchangeably in different embodiments of this application. "At least one" means one or more, and "a plurality of means two or more. The term "and / or" describes an association relationship of associated objects, and indicates that three relationships may exist. For example, A and / or B may indicate the following three cases: Only A exists, both A and B exist, and only B exists, where A and B may be singular or plural. The character " / " indicates an "or" relationship between associated objects. "At least one of the following items (pieces)" or a similar expression thereof indicates any combination of these items, including a single item (piece) or any combination of a plurality of items (pieces). For example, "at least one of A, B, or C" includes: only A; only B; only C; A and B; A and C; B and C; or A, B, and C, and "at least one of A, B, and C" may also be understood as including: only A; only B; only C; A and B; A and C; B and C; or A, B, and C. In addition, unless otherwise specified, ordinal numbers such as "first" and "second" in embodiments of this application are used to distinguish between a plurality of objects, and are not used to limit a sequence, a time sequence, priorities, or importance of the plurality of objects.

[0255] A person skilled in the art should understand that embodiments of this application may be provided as a method, an apparatus (or system), computer-readable storage medium, or a computer program product. Therefore, this application may use a form of a hardware-only embodiment, a software-only embodiment, or an embodiment with a combination of software and hardware. Moreover, this application may use a form of a computer program product that is implemented on one or more computer-usable storage media (including but not limited to a disk memory, an optical memory, and the like) that include computer-usable program code.

[0256] This application is described with reference to the flowcharts and / or block diagrams of the method, the device (system), and the computer program product according to this application. It should be understood that computer program instructions may be used to implement each process and / or each block in the flowcharts and / or the block diagrams and a combination of a process and / or a block in the flowcharts and / or the block diagrams. The computer program instructions may be provided for a general-purpose computer, a dedicated computer, an embedded processor, or a processor of another programmable data processing device and enable a machine to execute the instructions. When executed by any computer or the processor of a programmable data processing device, the instructions cause the apparatus to implement specific functions as described in one or more procedures in the flowcharts and / or one or more blocks in the block diagrams. The computer program instructions may alternatively be stored in a computer-readable memory that can indicate a computer or another programmable data processing device to work in a specific manner, so that the instructions stored in the computer-readable memory generate an artifact that includes an instruction apparatus. The instruction apparatus implements a specific function in one or more procedures in the flowcharts and / or one or more blocks in the block diagrams.

[0257] The computer program instructions may alternatively be loaded onto a computer or another programmable data processing device, so that a series of operations and steps are performed on the computer or the another programmable device, so that computer- implemented processing is generated. Therefore, the instructions executed on the computer or on another programmable device provide steps for implementing specific functions as described in one or more procedures in the flowcharts and / or one or more blocks in the block diagrams.

[0258] It is clear that a person skilled in the art can make various modifications and variations to this application without departing from the scope of this disclosure. This disclosure is intended to cover these modifications and variations of this application provided that they fall within the scope of protection defined by the following claims and their equivalent technologies.

Claims

CLAIMS1. A communication method, comprising: receiving a first reference signal and a second reference signal; obtaining first channel information and second channel information by performing channel measurements using the first reference signal and the second reference signal, respectively, wherein the first reference signal is transmitted on first frequency domain resources indicated by a first sampling sequence, the second reference signal is transmitted on second frequency domain resources indicated by a second sampling sequence, and the first sampling sequence and the second sampling sequence are comb coprime sequences; obtaining time delays of a full channel based on the first channel information and the second channel information; and obtaining third channel information based on the time delays, wherein the third channel information comprises full channel information.

2. The method of claim 1, wherein obtaining the time delays of the full channel based on the first channel information and the second channel information comprises: obtaining a covariance matrix based on the first channel information and the second channel information; obtaining a first vector by vectorizing the covariance matrix; and obtaining the time delays based on the first vector.

3. The method of claim 2, wherein obtaining the time delays based on the first vector comprises: obtaining a second vector by processing the first vector; and obtaining the time delays based on the second vector.

4. The method of claim 3, wherein obtaining the time delays based on the second vector comprises: obtaining the time delays based on the second vector using compressed sensing or least squares.

5. The method of any one of claims 1 to 4, further comprising: obtaining coefficients estimation, wherein obtaining the third channel information based on the time delays comprises: obtaining first dictionary information based on the time delays, wherein the first dictionary information is for indicating steering vectors of the full channel; and obtaining the third channel information based on the coefficients estimation and the first dictionary information.

6. The method of claim 5, wherein obtaining the coefficients estimation comprises: obtaining second dictionary information for indicating steering vectors of channels in the full channel corresponding to the first sampling sequence and the second sampling sequence; obtaining frequency response information for indicating frequency response of the channels corresponding to the first sampling sequence and the second sampling sequence; and obtaining the coefficients estimation based on the second dictionary information and the frequency responseinformation.

7. The method of any one of claims 1 to 6, wherein the first sampling sequence has a step of C * P1 ;and the second sampling sequence has a step of C * P2, where C is a regular transmission comb value,is a first coprime step value, P2is a second coprime step value, C, Prand P2are positive integers, and P1is coprime to P2.

8. The method of claim 7, wherein a number of elements in the first sampling sequence is(2P2— 1), and a number of elements in the second sampling sequence is (P±— 1).

9. The method of claim 7 or 8, wherein Prand P2are determined based on a quantity of resource units in the frequency domain resources.

10. The method of claim 9, wherein Prand P2satisfy:Nsc« (2P2~ 1) • CP±, where Nscis the quantity of the resource units in the frequency domain resources.

11. The method of any one of claims 7 to 10, wherein the first frequency domain resources comprise multiple first frequency units, and indices of the multiple first frequency units are determined based on a starting position of the multiple first frequency units, the regular transmission comb value C , and the first coprime step value P , and / or the second frequency domain resources comprise multiple second frequency units, and indices of the second frequency units are determined based on a starting position of the multiple second frequency units, the regular transmission comb value C , and the second coprime step value P2.

12. The method of any one of claims 1 to 11, further comprising: transmitting first information for indicating at least one of: time domain resources for transmitting the first reference signal and / or the second reference signal, quantity of time domain units in the time domain resources for transmitting the first reference signal and / or the second reference signal, a starting position of the first frequency domain resources and / or a starting positing of the second frequency domain resources, the regular transmission comb value C, a first coprime step value Pi, a second coprime step value P2, or an index of the first information associated to the first reference signal and / or the second signal.

13. A communication method, comprising: determining a first sampling sequence and a second sampling sequence, wherein the first sampling sequence is for indicating first frequency domain resources, the second sampling sequence is for indicating second frequency domain resources, and the first sampling sequence and the second sampling sequence are coprimesequences; transmitting a first reference signal on the first frequency domain resources based on the first sampling sequence; and transmitting a second reference signal on the second frequency domain resources based on the second sampling sequence.

14. The method of claim 13, wherein the first sampling sequence has a step of C * P15and the second sampling sequence has a step of C * P2, Pi , where C is a regular transmission comb value, P1is a first coprime step value, P2is a second coprime step value, C, Pi and P2are positive integers, and P1is coprime to P2.

15. The method of claim 14, wherein a number of elements in the first sampling sequence is (2P2— 1) and a number of elements in the second sampling sequence is (Pt — 1).

16. The method of claim 14 or 15, wherein PTand P2are determined based on a quantity of resource units in the frequency domain resources.

17. The method of claim 16, wherein and P2satisfy:Nsc» (2P2- 1) • CPltwhere Nscis the quantity of the resource units in the frequency domain resources.

18. The method of any one of claims 14 to 17, wherein the first frequency domain resources comprise multiple first frequency units, and indices of the multiple first frequency units are determined based on a starting position of the multiple first frequency units, the regular transmission comb value C , and the first coprime step value Ptand / or the second frequency domain resources comprise multiple second frequency units, and indices of the multiple second frequency units are determined based on a starting position of the multiple second frequency units, the regular transmission comb value C , and the second coprime step value P2.

19. The method of any one of claims 13 to 18, further comprising: receiving first information for indicating at least one of: time domain resources for transmitting the first reference signal and / or the second reference signal, quantify of time domain units in the time domain resources for transmitting the first reference signal and / or the second reference signal, a starting position of the first frequency domain resources and / or a starting positing of the second frequency domain resources, a regular transmission comb value C, a first coprime step value P15a second coprime step value P2, or an index of the first information associated to the first reference signal and / or the second signal, wherein determining the first sampling sequence and the second sampling sequence comprises:determining the first sampling sequence and the second sampling sequence based on the first information.

20. A communication apparatus, configured to perform the method according to any one of claims 1 to 19.

21. The communication apparatus of claim 20, comprising: a receiving unit configured to receive a first reference signal and a second reference signal; and a processing unit configured to: obtain first channel information and second channel information by performing channel measurements using the first reference signal and the second reference signal, respectively, wherein the first reference signal is transmitted on first frequency domain resources indicated by a first sampling sequence, the second reference signal is transmitted on second frequency domain resources indicated by a second sampling sequence, and the first sampling sequence and the second sampling sequence are comb coprime sequences; obtain time delays of a full channel based on the first channel information and the second channel information; and obtain third channel information based on the time delays, wherein the third channel information comprises full channel information.

22. The communication apparatus of claim 20, comprising: a processing unit configured to determine a first sampling sequence and a second sampling sequence, wherein the first sampling sequence is for indicating first frequency domain resources, the second sampling sequence is for indicating second frequency domain resources, and the first sampling sequence and the second sampling sequence are coprime sequences; and a transmitting unit configured to: transmit a first reference signal on the first frequency domain resources based on the first sampling sequence, and transmit a second reference signal on the second frequency domain resources based on the second sampling sequence.

23. The communication apparatus of claim 20, comprising: an interface circuit configured to receive a first reference signal and a second reference signal; and one or more processors configured to: obtain first channel information and second channel information by performing channel measurements using the first reference signal and the second reference signal, respectively, wherein the first reference signal is transmitted on first frequency domain resources indicated by a first sampling sequence, the second reference signal is transmitted on second frequency domain resources indicated by a second sampling sequence, and the first sampling sequence and the second sampling sequence are comb coprime sequences; obtain time delays of a full channel based on the first channel information and the second channel information; andobtain third channel information based on the time delays, wherein the third channel information comprises full channel information.

24. The communication apparatus of claim 20, comprising: one or more processors configured to determine a first sampling sequence and a second sampling sequence, wherein the first sampling sequence is for indicating first frequency domain resources, the second sampling sequence is for indicating second frequency domain resources, and the first sampling sequence and the second sampling sequence are coprime sequences; and an interface circuit configured to: transmit a first reference signal on the first frequency domain resources based on the first sampling sequence, and transmit a second reference signal on the second frequency domain resources based on the second sampling sequence.

25. The communication apparatus of claim 23 or 24, wherein the interface circuit comprises one or more transceivers.

26. An apparatus comprising: one or more processors; and a memory storing instructions which, when executed by the one or more processors, cause the apparatus to perform the method of any one of claims 1 to 19.

27. A communication system comprising a first communication apparatus configured to perform the method of any one of claims 1 to 12 and a second communication apparatus configured to perform the method of any one of claims 13 to 19.

28. A computer-readable storage medium having instructions stored thereon which, when executed by one or more processors, cause the one or more processors to perform the method of any one of claims 1 to 19.

29. A computer program product storing instructions which, when executed, cause an apparatus to perform the method of any one of claims 1 to 19.

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