Electronic devices, methods, apparatuses, and storage media for wireless communication systems

Abstract

The present disclosure relates to electronic devices, methods and storage media for wireless communication systems. Embodiments of the present disclosure carry reference signals on only some of the communication resources for channel estimation. According to embodiments of the present disclosure, a channel state on the communication resources carrying the reference signals is estimated; using the estimated channel state of the communication resources, a channel path condition from a transmitter to a receiver is estimated. From the estimated channel path condition, the channel state of the transmitter to the receiver on other communication resources can be derived.

Description

[0001] This application is a divisional application of the application with the application number 201880072249.X, the application date of November 14, 2018, and the invention patent application name of "Electronic device, method, apparatus and storage medium for wireless communication system".

[0002] Cross Reference to Related Applications

[0003] The present disclosure claims priority to Chinese Patent Application No. 201711125720.0, filed on November 15, 2017, the disclosure of which is incorporated herein in its entirety as part of the present disclosure. TECHNICAL FIELD

[0004] The present disclosure relates generally to wireless communication systems, and in particular, to techniques for channel estimation. BACKGROUND

[0005] With the development and wide application of mobile Internet technology, wireless communication has never before met the voice and data communication needs of people. With the increase of frequency bands (such as 26 GHz, 60 GHz or higher frequency bands), wireless channels will inevitably suffer greater path loss, atmospheric absorption loss and other negative effects than low frequency bands (such as 2 GHz). In order to provide higher communication quality and capacity, wireless communication systems have adopted various technologies at different levels.

[0006] In recent years, Massive Multi-Input Multi-Output (MIMO) technology and millimeter wave (mmWave) technology have been considered as part of the key technologies of future 5G, and have attracted widespread attention from academia and industry. The millimeter wave frequency band has a large amount of available spectrum resources, which can meet the increasing traffic demand of mobile communication. In addition, due to the shorter wavelength of millimeter waves, according to antenna theory, the antenna size of the millimeter wave system is also smaller, which makes it possible to place several hundred or even thousands of antennas in a small space, which is more conducive to the application of large-scale antenna technology in real systems.

[0007] Furthermore, in massive MIMO (Massively Multi-Signal) antenna technology, beamforming can effectively compensate for the excessive path fading in millimeter-wave channels, making the application of millimeter-wave technology in mobile communications possible. Beamforming can increase the directivity of antenna transmission and / or reception, providing beamforming gain to compensate for wireless signal loss. To this end, 3GPP introduced the concept of beam management in the 5G standard, one important process of which is beam sweeping. In beam sweeping technology, the matching transmit and receive beams between the base station and the terminal equipment are found through the beam sweeping process, thereby establishing a beam pair link (BPL) between the base station and the terminal equipment.

[0008] In millimeter-wave communication, the introduction of large-scale antenna arrays greatly increases the dimension of the channel matrix (number of receiver antennas multiplied by number of transmitter antennas), making direct estimation of the channel matrix highly complex and incurring significant overhead for the reference signal. Summary of the Invention

[0009] In response to the above, this disclosure provides electronic devices, methods, apparatus, and storage media for wireless communication systems.

[0010] One aspect of this disclosure relates to an electronic device for a receiver in a wireless communication system. According to one embodiment, the electronic device may include processing circuitry. This processing circuitry may be configured to estimate channel states on communication resources carrying a reference signal from a transmitter, wherein the reference signal is distributed across communication resources in a first frequency domain range of the communication system, the frequency domain resources of the communication system being divided into a plurality of orthogonal frequency domain ranges encompassing the first frequency domain range; and to estimate channel path conditions from the transmitter to the receiver using the estimated channel states of the communication resources. The channel states from the transmitter to the receiver on communication resources in other frequency domain ranges are derived from the estimated channel path conditions.

[0011] One aspect of this disclosure relates to an electronic device for a receiver end of a wireless communication system. According to one embodiment, the electronic device may include processing circuitry. This processing circuitry may be configured to estimate channel states on communication resources carrying reference signals based on reference signals from a transmitter, wherein the reference signals are distributed in the frequency domain at predetermined intervals, and the predetermined intervals are determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system; and to estimate channel path conditions from the transmitter to the receiver using the estimated channel states of the communication resources. The channel states from the transmitter to the receiver on other communication resources are derived from the estimated channel path conditions.

[0012] One aspect of this disclosure relates to an electronic device for a transmitter in a wireless communication system. According to one embodiment, the electronic device may include processing circuitry. This processing circuitry may be configured to determine that a reference signal will be disposed only on communication resources within a first frequency domain range of the communication system; and to transmit the reference signal to a receiver via the communication resources within the first frequency domain range. The frequency domain resources of the communication system are divided into a plurality of orthogonal frequency domain ranges encompassing the first frequency domain range. The channel path condition from the transmitter to the receiver is derived based on channel estimation on the communication resources within the first frequency domain range, and the channel state from the transmitter to the receiver on communication resources in other frequency domain ranges is derived from the estimated channel path condition.

[0013] One aspect of this disclosure relates to an electronic device for a transmitter end of a wireless communication system. According to some embodiments, the electronic device may include processing circuitry. This processing circuitry may be configured to transmit a reference signal to a receiver end of the wireless communication system via communication resources, wherein the reference signal is distributed in the frequency domain at predetermined intervals, and the predetermined intervals are determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system. The channel state on the communication resources carrying the reference signal can be estimated based on the reference signal from the transmitter end. The channel path condition from the transmitter to the receiver can be estimated using the estimated channel state on the communication resources. The channel state from the transmitter to the receiver on other communication resources can be derived from the estimated channel path condition.

[0014] Another aspect of this disclosure relates to a method for a receiver in a wireless communication system. According to some embodiments, the method includes estimating channel states on communication resources carrying the reference signal based on a reference signal from a transmitter, wherein the reference signal is distributed over communication resources in a first frequency domain range of the communication system, the frequency domain resources of the communication system being divided into a plurality of orthogonal frequency domain ranges encompassing the first frequency domain range; and estimating channel path conditions from the transmitter to the receiver using the estimated channel states of the communication resources. The channel states from the transmitter to the receiver on communication resources in other frequency domain ranges can be derived from the estimated channel path conditions.

[0015] Another aspect of this disclosure relates to a method for a receiver in a wireless communication system. According to some embodiments, the method may include estimating channel states on communication resources carrying reference signals based on reference signals from a transmitter, wherein the reference signals are distributed in the frequency domain at predetermined intervals, and the predetermined intervals are determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system; and estimating channel path conditions from the transmitter to the receiver using the estimated channel states of the communication resources. The channel states from the transmitter to the receiver on other communication resources are derived from the estimated channel path conditions.

[0016] Another aspect of this disclosure relates to a method for a transmitter in a wireless communication system. According to some embodiments, the method may include determining that a reference signal will be deployed only on communication resources within a first frequency domain range of the communication system; and transmitting the reference signal to a receiver via the communication resources within the first frequency domain range. The frequency domain resources of the communication system are divided into a plurality of orthogonal frequency domain ranges encompassing the first frequency domain range. The channel path condition from the transmitter to the receiver is derived based on channel estimation on the communication resources within the first frequency domain range. The channel state from the transmitter to the receiver on communication resources in other frequency domain ranges is derived from the estimated channel path condition.

[0017] Another aspect of this disclosure relates to a method for a transmitter in a wireless communication system. According to some embodiments, the method may include transmitting a reference signal to a receiver in the wireless communication system via communication resources. The reference signal is distributed in the frequency domain at predetermined intervals, and the predetermined intervals are determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system. The channel state on the communication resources carrying the reference signal is estimated based on the reference signal from the transmitter. The channel path condition from the transmitter to the receiver is estimated using the estimated channel state on the communication resources. The channel state from the transmitter to the receiver on other communication resources is derived from the estimated channel path condition.

[0018] Another aspect of this disclosure relates to a computer-readable storage medium storing one or more instructions. In some embodiments, the one or more instructions, when executed by one or more processors of an electronic device, can cause the electronic device to perform methods according to various embodiments of this disclosure.

[0019] Another aspect of this disclosure relates to various apparatuses, including components or units for performing operations of methods according to embodiments of this disclosure.

[0020] Another aspect of this disclosure relates to a computer program product comprising instructions that, when executed by one or more processors, cause the one or more processors to perform methods according to various embodiments of this disclosure.

[0021] Another aspect of this disclosure relates to a computer program containing instructions that, when executed by one or more processors, cause the one or more processors to perform methods according to various embodiments of this disclosure.

[0022] The above overview is provided to summarize some exemplary embodiments to provide a basic understanding of the aspects of the subject matter described herein. Therefore, the features described above are merely examples and should not be construed as narrowing the scope or spirit of the subject matter described herein in any way. Other features, aspects, and advantages of the subject matter described herein will become apparent from the following detailed description, taken in conjunction with the accompanying drawings. Attached Figure Description

[0023] A better understanding of this disclosure can be obtained by considering the following detailed description of the embodiments in conjunction with the accompanying drawings. The same or similar reference numerals are used in the drawings to denote the same or similar parts. The drawings, together with the following detailed description, are incorporated in and form a part of this specification to illustrate embodiments of the disclosure and explain the principles and advantages of the disclosure. Wherein:

[0024] Figure 1The conceptual structure of a base station is illustrated schematically.

[0025] Figure 2 The conceptual structure of the user equipment is illustrated schematically.

[0026] Figure 3 An exemplary beamforming operation is illustrated schematically.

[0027] Figure 4a and 4b The diagrams illustrate the configurations of the base station and user equipment in a single-user system, respectively.

[0028] Figure 5 An exemplary communication system is shown.

[0029] Figure 6A An exemplary electronic device for a receiver end is shown according to an embodiment of the present disclosure.

[0030] Figure 6B An exemplary electronic device for a transmitter end is shown according to an embodiment of the present disclosure.

[0031] Figure 7 This is a schematic diagram of the transceiver structure of a millimeter-wave massive MIMO antenna system.

[0032] Figure 8 This is a schematic diagram of a millimeter-wave channel model.

[0033] Figure 9 A conceptual flowchart of channel estimation according to an embodiment of this disclosure is shown.

[0034] Figure 10 This is a schematic diagram of a sparse pilot pattern in the frequency domain.

[0035] Figure 11 A conceptual flowchart of channel path condition estimation according to an embodiment of the present disclosure is shown.

[0036] Figure 12 This is a schematic diagram of a DFT result, where L = 1.

[0037] Figure 13 This is a schematic diagram of a DFT result, where L = 3.

[0038] Figure 14 This is a schematic diagram of a reference signal to time-frequency resource mapping example according to one embodiment.

[0039] Figure 15 This is a schematic diagram of a reference signal to time-frequency resource mapping example according to another embodiment.

[0040] Figure 16This is a schematic diagram comparing channel estimation simulation results with pilots inserted only on half the bandwidth, where the real part is SNR = -10dB.

[0041] Figure 17 A schematic diagram comparing channel estimation simulation results with full-band pilot insertion, where the real part is SNR = -10dB.

[0042] Figure 18 This is a diagram illustrating the performance simulation comparison of MSE.

[0043] Figure 19 An application example of downlink CSI-RS transmission in an asymmetric scenario is shown.

[0044] Figure 20 An application example of uplink CSI-RS transmission in an asymmetric scenario is shown.

[0045] Figure 21 An application example of uplink SRS transmission in a symmetrical scenario is shown.

[0046] Figure 22 An application example of downlink SRS transmission in a symmetrical scenario is shown.

[0047] Figure 23 This paper presents an application example of downlink CSI-RS transmission in another asymmetric scenario.

[0048] Figure 24 An application example of DMRS downlink transmission is shown.

[0049] Figure 25 This demonstrates an application example of DMRS uplink transmission.

[0050] Figure 26 A block diagram of an example structure of a personal computer that may be used as an information processing device in embodiments of this disclosure;

[0051] Figure 27 A block diagram illustrating a first example of a illustrative configuration of a gNB to which the techniques of this disclosure may be applied;

[0052] Figure 28 A block diagram illustrating a second example of a illustrative configuration of a gNB to which the techniques of this disclosure may be applied;

[0053] Figure 29 A block diagram illustrating an example of a schematic configuration of a smartphone to which the technologies of this disclosure can be applied; and

[0054] Figure 30 A block diagram illustrating an example of a schematic configuration of a car navigation device to which the techniques of this disclosure can be applied.

[0055] While the embodiments described in this disclosure may be readily modified and alternatively implemented, specific embodiments thereof are shown by way of example in the accompanying drawings and are described in detail herein. However, it should be understood that the drawings and the detailed description thereof are not intended to limit the embodiments to the specific forms disclosed, but rather are intended to cover all modifications, equivalents, and alternatives that fall within the spirit and scope of the claims. Detailed Implementation

[0056] The following description illustrates representative applications of the devices and methods described herein. These examples are provided merely to provide context and aid in understanding the described embodiments. Therefore, it will be apparent to those skilled in the art that the embodiments described below can be practiced without some or all of the specific details provided. In other instances, well-known process steps have not been described in detail to avoid unnecessarily obscuring the described embodiments. Other applications are also possible, and the scope of this disclosure is not limited to these examples.

[0057] Typically, a wireless communication system includes at least a base station and a user equipment (UE), with the base station providing communication services to one or more UEs.

[0058] In this disclosure, the term "base station" is used in its full breadth of its usual meaning and includes at least a wireless communication station used as part of a wireless communication system or radio system to facilitate communication. As examples, a base station may be an eNB of the 4G communication standard, a gNB of the 5G communication standard, a remote radio head, a wireless access point, a drone control tower, or a communication device performing similar functions. Examples of base station applications will be described in detail below with reference to the accompanying drawings.

[0059] In this disclosure, the term "user equipment" or "UE" is used in its full breadth of its usual meaning and includes at least a terminal device used as part of a wireless communication system or radio system to facilitate communication. As examples, a UE can be a terminal device or component thereof, such as a mobile phone, laptop, tablet computer, in-vehicle communication device, etc. Application examples of UEs will be described in detail in later sections.

[0060] In this disclosure, the term "transmitter end" / "transmitter terminal" has the full breadth of its usual meaning and generally refers to one end of a transmitted signal stream in a communication system. Depending on the direction of the signal stream in the communication system, such as uplink / downlink signal transmission, "transmitter end" / "transmitter terminal" can refer to the "base station" or "user equipment" end in the communication system. Similarly, the term "receiver end" / "receiver terminal" has the full breadth of its usual meaning and can accordingly refer to the "user equipment" or "base station" end in a communication system.

[0061] It should be noted that although the following description of embodiments of this disclosure is primarily based on a communication system including a base station and user equipment, these descriptions can be extended accordingly to communication systems including a transmitter and a receiver. For example, depending on the direction of the signal flow in the communication system, the operation of the transmitter may correspond to the operation of the base station or the operation of the user equipment, and the operation of the receiver may correspondingly correspond to the operation of the user equipment or the operation of the base station.

[0062] Base stations and UEs can have multiple antennas supporting MIMO technology. The use of MIMO technology enables base stations and UEs to utilize spatial domains to support spatial multiplexing, beamforming, and transmit diversity. Spatial multiplexing can be used to simultaneously transmit different data streams on the same frequency. These data streams can be sent to a single UE to increase the data rate (referred to as SU-MIMO technology) or to multiple UEs to increase the overall system capacity (referred to as MU-MIMO technology). This is achieved by spatially precoding each data stream (i.e., performing amplitude scaling and / or phase adjustment) and then transmitting each spatially precoded stream over the downlink (DL) from the base station to the UE via multiple transmit antennas. The spatially precoded data streams arrive at one or more UEs with distinct spatial signatures, allowing each UE to receive the data streams via its multiple antennas and recover one or more data streams destined for that UE. On the uplink (UL) from the UE to the base station, each UE transmits the spatially precoded data streams through its multiple antennas, allowing the base station to receive the data streams via its antennas and identify the source of each spatially precoded data stream.

[0063] In wireless communication systems, typically, at the transmitting end (e.g., base station) and the receiving end (e.g., user equipment), each antenna is connected to a radio frequency (RF) link for transmission and reception. Generally speaking, in operation, at the transmitting end, the data stream to be transmitted first undergoes baseband processing, and then is converted into an RF signal via the RF link for transmission through the corresponding antenna. At the receiving end, the corresponding RF link processes the received RF signal into a baseband signal, and then performs further baseband processing to obtain the desired data stream.

[0064] Typically, in baseband data processing, to facilitate the multiplexing of multiple data streams using the same transmission resources via radio frequency links and corresponding antennas, a digital precoding architecture is mainly employed. The amplitude of the transmitted signal on each radio frequency link is adjustable to reduce interference between multiple data signals carried on the same transmission resources. This processing before data is transmitted via radio frequency links and antennas can be referred to as baseband digital processing of the data at the transmitting end.

[0065] For the digital precoding matrix used in digital precoding, there are generally two design approaches: codebook-based and non-codebook-based. In the codebook-based design, the digital precoding matrix must be selected from a pre-defined codebook. In the non-codebook-based design, there is no such constraint. The base station and user end can design the precoding matrix based on Channel State Information (CSI). The digital precoding process described above can be considered part of the baseband digital processing section of wireless communication.

[0066] For example, Figure 1 The diagram schematically illustrates a conceptual structure of a prior art base station. For example... Figure 1 As shown, in the digital precoding architecture, the base station is equipped with M antennas (M is an integer and M≥1), and each antenna has a corresponding radio frequency link. Under the control of the controller, the digital precoder acquires K data streams (K is an integer and K≥1) and performs digital precoding on these K data streams (for example, by passing the K data streams through a digital precoding matrix B of size M×K). The encoded data is then transmitted to one or more users via the radio frequency link and antennas.

[0067] Accordingly, the user end can have various configuration options to perform corresponding baseband digital processing after receiving the encoded data through the radio frequency link in order to obtain the desired data stream.

[0068] Figure 2 A user terminal configured with multiple antennas is shown. For example... Figure 2 As shown, the user terminal is configured with N antennas (N is an integer and N≥1). Each antenna transmits the received data to the digital precoder via a corresponding RF link. Under the control of the controller, the digital precoder uses a digital precoding matrix W of, for example, size Ku×N (Ku is an integer and Ku≧1) to digitally precode the received data, thereby obtaining single-channel (when Ku=1) or multiple-channel data (when Ku>1).

[0069] For the digital precoding matrix used in digital precoding, there are generally two design approaches: codebook-based and non-codebook-based. In the codebook-based design, the digital precoding matrix must be selected from a pre-defined codebook. In the non-codebook-based design, there is no such constraint. The base station and user end can design the precoding matrix based on Channel State Information (CSI). The digital precoding process described above is generally considered to belong to the baseband digital processing part of wireless communication.

[0070] Furthermore, in wireless communication systems, especially high-frequency systems such as millimeter-wave communication systems, a directional beam can be formed using as few as one RF link by connecting multiple phase shifters and antennas to each RF link, thereby realizing an analog beamforming scheme. Analog beamforming training refers to the process of optimizing the RF configuration information of the base station and user equipment (e.g., the configuration values ​​of the phase shifters of the base station and user equipment, also known as the weight vectors for the phase shifters), its main function being to improve the signal-to-noise ratio (SNR) of the user equipment. Taking the downlink as an example, the base station forms a directional transmit beam by configuring the values ​​of multiple phase shifters connected to its multiple antennas, and the user equipment forms a directional receive beam by configuring the values ​​of multiple phase shifters connected to its multiple antennas. The base station's transmit beam and the user equipment's receive beam constitute a beam pair in the downlink. The downlink beamforming training process is the process of finding an optimal beam pair consisting of the optimal base station transmit beam and the optimal user equipment receive beam. Similarly, in the uplink, the base station's receive beam and the user equipment's transmit beam also constitute a beam pair.

[0071] The following is combined with Figure 3 This section provides a brief introduction to the beam scanning process in wireless communication systems. Figure 3 The right-hand arrow indicates the downlink direction from base station 100 to terminal device 104, and the left-hand arrow indicates the uplink direction from terminal device 104 to base station 100. For example... Figure 3 As shown, base station 100 includes n t_DL downlink transmit beams (n t_DL For any natural number greater than or equal to 1, Figure 3 Example n t_DL =9), terminal device 104 includes n r_DL downlink receiving beams (n r_DL For natural numbers greater than or equal to 1, Figure 3 Example n r_DL =5). Additionally, in Figure 3 In the wireless communication system shown, the number n of uplink receiving beams of base station 100 r_UL And the coverage area of ​​each beam is the same as that of the downlink transmit beam, and the number of uplink transmit beams n of the terminal device 104. t_UL Furthermore, the coverage area of ​​each beam is the same as that of the downlink receiving beam. It should be understood that, depending on system requirements and settings, the coverage area and number of uplink receiving beams and downlink transmitting beams of the base station can differ, and the same applies to terminal equipment.

[0072] like Figure 3 As shown, during downlink beam scanning, the n of base station 100 t_DLEach of the downlink transmit beams 102 sends n to the terminal device 104. r_DL A downlink reference signal, terminal device 104 via n r_DL Each downlink receiving beam receives the n... r_DL One downlink reference signal. In this way, the n of base station 100 t_DL Each downlink transmit beam sequentially sends n to terminal device 104 t_DL ×n r_DL Each downlink reference signal is received by the terminal device 104, and each downlink receiving beam 106 receives n. t_DL One downlink reference signal, namely n of terminal device 104 r_DL The downlink receiving beams receive a total of n signals from base station 100. t_DL ×n r_DL One downlink reference signal. Terminal device 104 to this n t_DL ×n r_DL The downlink reference signal is measured (e.g., the received signal power of the downlink reference signal is measured (e.g., RSRP)). The downlink transmit beam of the base station 100 and the downlink receive beam of the terminal device 104 when the measurement result is better or the best are determined as the downlink matched transmit and receive beam pair, and the downlink beam pair link (hereinafter referred to as BPL) is established.

[0073] During uplink beam scanning, similar to downlink beam scanning, the n of terminal device 104... t_UL Each of the uplink transmit beams 106 sends n to the base station 100. r_UL One uplink reference signal, base station 100 via n r_UL Each uplink receiving beam receives the n... r_UL One uplink reference signal. In this way, the n of the terminal device 104 t_UL Each uplink transmit beam sequentially sends n to base station 100 t_UL ×n r_UL Each uplink reference signal is received by each uplink receiving beam 102 of base station 100. t_UL One uplink reference signal, namely n of base station 100 r_UL The uplink receive beams received a total of 104 n signals from the terminal equipment. r_UL ×n t_UL One uplink reference signal. Base station 100 to this n r_UL ×n t_UL The uplink reference signal is measured (e.g., the received signal power of the uplink reference signal is measured (e.g., RSRP)), so that the uplink transmit beam of the terminal device 104 and the uplink receive beam of the base station 100 when the measurement result is better or better are determined as the uplink matched transmit and receive beam pair, and the uplink beam pair link is established.

[0074] It should be understood that the coverage and number of uplink receiving beams and downlink transmitting beams of a base station may be different, and the coverage and number of uplink transmitting beams and downlink receiving beams of a terminal device may be different, but the above-mentioned determination operation can still be performed similarly.

[0075] The receive and transmit beams of base stations and terminal equipment can be generated using DFT (Discrete Fourier Transform) vectors. The following explanation uses the downlink transmit beam on the base station side as an example; the uplink receive beam on the base station side and the transmit / receive beams on the terminal equipment side can also be generated using a similar method.

[0076] For example, suppose that n are equipped on the base station side t With one transmitting antenna, the equivalent channel from the base station to the terminal device can be represented as an n... t A vector H of size 1. The DFT vector u can be represented as:

[0077]

[0078] Where the length of the DFT vector u is n t C represents the parameter used to adjust the beamwidth and shaping gain, and "T" represents the transpose operator.

[0079] Multiplying the equivalent channel H from the base station to the terminal device by the DFT vector u yields a transmit beam of the base station (e.g., Figure 3 (One of the downlink transmit beams shown).

[0080] In one embodiment, the parameter C used to adjust the beamwidth and shaping gain in the above formula can be represented by the product of two parameters O2 and N2. By adjusting the two parameters O2 and N2 respectively, the beamwidth and shaping gain can be adjusted. Generally, the number of antennas n t The larger the value of O2, or the larger the parameter C (e.g., the product of O2 and N2), the stronger the spatial directivity of the resulting beam, but the narrower the beamwidth is generally. In one embodiment, O2 = 1 and N2 = 1 can be set, so the resulting DFT vector u is n t A vector in which all elements are 1.

[0081] After completing the downlink and uplink beam scanning processes, the established BPL is used for subsequent data and / or control signal transmission. The process described above, which uses beam scanning to determine the matched transmit / receive beam pairs between the base station and terminal equipment, is sometimes also referred to as beam training.

[0082] Millimeter-wave communication systems have various operating modes, such as point-to-point mode, single-user mode, and multi-user mode. Point-to-point mode can be used for backhaul between base stations (BS), while single-user and multi-user modes can be used for communication between a base station and one or more user equipments (UE). In terms of implementation architecture, it can include purely analog beamforming architectures (e.g., fully connected architectures or sub-connected architectures without digital precoding), fully connected hybrid analog-digital precoding architectures, and sub-connected hybrid analog-digital precoding architectures.

[0083] Figure 4a and Figure 4b The configurations of the base station and user end in a single-user system are shown separately. For example... Figure 4a and Figure 4b As shown, each RF link at both the user and base station ends is connected to a set of phase shifters, which in turn are connected to their respective antennas. The values ​​of a set of phase shifters (e.g., phase values) can be indicated by a set of configuration parameters, such as a DFT vector, also known as a weight vector or beam vector. In this paper, we denote the weight vector at the base station end as f and the weight vector at the user end as w. Since the phase shifters in this example only adjust the phase of the signal without changing the amplitude, the amplitude of each element in the weight vector is 1. In millimeter-wave communication systems with this structure, due to the limited number of RF links, neither the base station nor the user end can directly estimate channel state information. Therefore, typical analog beamforming schemes employ a method based on an analog Tx / Rx codebook. The codebook is a set of weight vectors. Let the base station codebook be F with a size of P (containing P weight vectors) and the user codebook be W with a size of Q (containing Q weight vectors). Then the weight vectors of the base station must be selected from the base station codebook F, and the weight vectors of the user must be selected from the user codebook W.

[0084] When conducting millimeter-wave communication between the base station and the user end, the specific weight vector in the codebook to be used must be determined beforehand through beam training. Beam training can, for example, use a maximum signal-to-noise ratio criterion to determine the weight vector used to form the optimal beam, which can be expressed by the following formula:

[0085] {w opt f opt}=argmax|w H Hf|where w∈W, f∈F

[0086] In the above formula, Let W represent the downlink channel between the base station and the user terminal, where W is the candidate set (codebook) of weight vectors at the user terminal, F is the candidate set (codebook) of weight vectors at the base station, and w... opt f opt These are the determined optimal weight vectors for the user end and the base station end, respectively.

[0087] Due to the high path attenuation characteristic of millimeter-wave channels, the number of scatterers in millimeter-wave multipath channels is relatively small. Therefore, the millimeter-wave channel H can typically be modeled as...

[0088]

[0089] Where N and M represent the number of antennas equipped at the user terminal and the base station, respectively. cl N represents the number of scatterers. ray The number of sub-radii contained in each scatterer, α i，l a represents the channel coefficient of the corresponding scattering path. UE and a BS Let θ and φ represent the antenna response vectors of the user terminal and the base station, respectively, and let θ and φ be the angles of arrival in the horizontal and vertical directions, respectively.

[0090] In millimeter-wave communication, there is a significant discrepancy between the number of radio frequency (RF) links and the number of antennas in both transmitters and receivers, with the number of RF links typically being much smaller than the number of antennas. Transmitters and receivers can multiply a single RF link by multiple antennas, using massive MIMO (Massively Large Array) antennas with simulated beamforming techniques to generate extremely high directional gain. Therefore, in millimeter-wave communication, it is often necessary to estimate the equivalent baseband channel matrix from the transmitter's RF link to the receiver's RF link. This equivalent baseband matrix has low dimensionality and is easy to estimate. The receiver can then estimate the equivalent baseband matrix and coherently demodulate the data transmitted by the transmitter.

[0091] Furthermore, Orthogonal Frequency Division Multiplexing (OFDM) has become the mainstream wireless communication technology due to its numerous advantages. For example, it is foreseeable that in next-generation mobile communication networks, OFDM will be combined with millimeter-wave communication and massive MIMO (Multiple-Input Multiple-Output) antennas. OFDM divides a relatively wide bandwidth used for communication into multiple narrowband subcarriers, each subcarrier corresponding to a flat-fading channel. In a system combining MIMO and OFDM, each subcarrier will correspond to a channel matrix, requiring estimation of the channel matrices for all subcarriers.

[0092] Several methods for estimating the channel matrix in millimeter-wave communication have been proposed. For example, due to the high path attenuation and reflection attenuation in millimeter-wave transmission, its channel exhibits sparsity, meaning the number of transmission paths is relatively small. Some known techniques estimate the channel matrix by introducing compressed sensing or further performing precoding design, but these methods have high implementation complexity and poor practicality.

[0093] Furthermore, traditional channel estimation methods used in orthogonal frequency division multiplexing (OFDM) systems involve transmitting pilot signals (reference signals) on certain subcarriers at regular intervals. The receiver first estimates the channel matrix corresponding to the subcarriers containing the pilot signals, and then estimates the channel matrix corresponding to the remaining subcarriers through interpolation. The use of interpolation requires the pilot signals to be inserted across the entire frequency band, resulting in significant pilot transmission overhead. However, in millimeter-wave communication, the bandwidth used is much larger, requiring a large number of subcarriers containing pilot signals in each transmitted OFDM symbol, thus sacrificing data rate.

[0094] On the other hand, to ensure the accuracy of the interpolation results, traditional interpolation methods rely on the channel's correlation bandwidth for the selection of frequency domain pilot spacing. This spacing is typically chosen as a multiple (e.g., 10 times, 20 times) of the channel's maximum delay spread, followed by the reciprocal. This results in a relatively dense pilot distribution in the frequency domain, leading to significant pilot transmission overhead and reduced data rate.

[0095] To reduce the pilot transmission overhead of traditional interpolation channel estimation methods, this disclosure proposes a novel channel estimation method by leveraging the sparsity of communication channels. Specifically, considering the sparsity of communication channels, this disclosure describes how improved channel estimation is achieved using an improved distribution of the reference signal in the frequency and / or time domains, and / or an improved channel path condition estimate.

[0096] Specifically, the embodiments of this disclosure essentially involve carrying reference signals on only a portion of the communication resources for channel estimation. According to embodiments of this disclosure, the channel state on the communication resources carrying the reference signals is estimated; using the estimated channel state of the communication resources, the channel path condition from the transmitter to the receiver is estimated. Thus, the channel state from the transmitter to the receiver on other communication resources can be derived from the estimated channel path condition.

[0097] The embodiments disclosed herein can be implemented in various ways and can be applied to various wireless communication systems, especially wireless communication systems with channel sparsity.

[0098] According to some embodiments, embodiments of this disclosure are particularly preferred for use in millimeter-wave orthogonal frequency division multiplexing systems, utilizing the sparsity of the millimeter-wave channel itself and its even stronger sparsity after beamforming to achieve improved channel estimation.

[0099] According to some embodiments, the embodiments of this disclosure can also be used in wireless communication systems that primarily communicate via a direct path. For example, in addition to millimeter-wave systems having the characteristic of a direct path, scenarios have emerged in traditional decimeter-wave / centimeter-wave systems where aircraft communicate with ground base stations. In such cases, the communication between the aircraft and the base station is also mostly a direct path with few obstacles, which is also suitable for the settings of this disclosure.

[0100] It should be noted that the above application scenarios are merely exemplary, and the embodiments disclosed herein can also be used in other wireless channel systems with channel sparsity.

[0101] According to one embodiment, an electronic device for a receiver in a wireless communication system is proposed. The electronic device may include processing circuitry. This processing circuitry is configured to estimate channel states on communication resources carrying a reference signal based on a reference signal from a transmitter, wherein the reference signal is distributed across communication resources in a first frequency domain range of the communication system, the frequency domain resources of the communication system being divided into multiple orthogonal frequency domain ranges encompassing the first frequency domain range; and to estimate channel path conditions from the transmitter to the receiver using the estimated channel states of the communication resources. The channel states from the transmitter to the receiver on communication resources in other frequency domain ranges are derived from the estimated channel path conditions.

[0102] According to one embodiment, an electronic device for a transmitter end of a wireless communication system is proposed. The electronic device may include processing circuitry. This processing circuitry may be configured to determine that a reference signal will be disposed only on communication resources within a first frequency domain range of the communication system; and to transmit the reference signal to a receiver end via the communication resources within the first frequency domain range. The frequency domain resources of the communication system are divided into a plurality of orthogonal frequency domain ranges encompassing the first frequency domain range. The channel path condition from the transmitter end to the receiver end is derived based on channel estimation on the communication resources within the first frequency domain range, and the channel state from the transmitter to the receiver on communication resources in other frequency domain ranges is derived from the estimated channel path condition.

[0103] According to one embodiment, an electronic device for a receiver end of a wireless communication system is proposed. The electronic device may include processing circuitry. This processing circuitry may be configured to estimate the channel state on communication resources carrying the reference signal based on a reference signal from a transmitter, wherein the reference signal is distributed in the frequency domain at predetermined intervals, and the predetermined intervals are determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system; and to estimate the channel path condition from the transmitter to the receiver using the estimated channel state of the communication resources. The channel state from the transmitter to the receiver on other communication resources is derived from the estimated channel path condition.

[0104] According to one embodiment, an electronic device for a transmitter end of a wireless communication system is proposed. The electronic device may include processing circuitry. This processing circuitry may be configured to transmit a reference signal to a receiver end of the wireless communication system via communication resources, wherein the reference signal is distributed in the frequency domain at predetermined intervals, and the predetermined intervals are determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system. The channel state on the communication resources carrying the reference signal can be estimated based on the reference signal from the transmitter end. The channel path condition from the transmitter to the receiver can be estimated using the estimated channel state on the communication resources. The channel state from the transmitter to the receiver on other communication resources can be derived from the estimated channel path condition.

[0105] It should be noted that the above embodiments can also be implemented in combination with each other. For example, when the frequency domain resources are divided into orthogonal frequency domain ranges, the reference signals can also be distributed at predetermined intervals in the frequency domain.

[0106] The basic implementation of embodiments of the present disclosure will now be described in detail with reference to the accompanying drawings. It should be noted that these basic implementations are equally applicable to the transmitter / receiver embodiments described above, as well as to other embodiments of the present disclosure.

[0107] Terminology Overview

[0108] The term "communication resources" has different meanings in different communication systems. For example, "communication resources" can refer to time-domain and / or frequency-domain resources. Taking LTE as an example, each LTE frame (10ms) can be divided into 10 equal-sized subframes. Each subframe (1ms) can include two consecutive time slots, and each time slot includes a resource block (RB). Resource blocks can be represented by a resource grid, which can be divided into multiple resource elements (REs). For example, each resource block contains 12 consecutive subcarriers in the frequency domain, and for each normal cyclic prefix in an OFDM symbol, each resource block contains 7 consecutive OFDM symbols in the time domain. That is, each resource block contains 84 resource elements. In such an LTE frame, symbols for user data or reference signals are assigned corresponding resource elements. However, besides time-frequency resources, "communication resources" can also refer to spatial domain resources or code domain resources, etc.

[0109] A reference signal is a known signal provided by the transmitter to the receiver for channel estimation or channel sounding. It can be used for various measurements to determine the actual channel conditions experienced by radio signals from the base station to the UE. Compared to theoretical methods such as geolocation estimation, channel estimation based on reference signals is more accurate. Reference signals are of great importance for mobility management, resource allocation, MIMO operation, and data demodulation.

[0110] Based on transmission direction, reference signals can be typically divided into uplink reference signals and downlink reference signals. In the time and / or frequency domains, reference signals are multiplexed with the user data stream in uplink or downlink frames, occupying certain communication resources within the frame. Downlink reference signals are predefined signals transmitted from the base station to the UE, occupying specific downlink communication resources (e.g., specific resource elements in a time-frequency resource block), and are used for downlink channel estimation, downlink channel sounding, cell search, etc. Examples of downlink reference signals include, but are not limited to, cell reference signals (CRS), data demodulation reference signals (DMRS), and channel state information reference signals (CSI-RS). Uplink reference signals are predefined signals transmitted from the UE to the base station, occupying specific uplink communication resources (e.g., specific resource elements in a time-frequency resource block), and are used for uplink channel estimation, uplink channel quality measurement, etc. Examples of uplink reference signals include, but are not limited to, DMRS and sounding reference signals (SRS). In one example, CSI-RS is used for downlink channel state feedback.

[0111] In the communication system disclosed herein, different reference signals typically have different use cases and purposes. For example, DMRS can be transmitted primarily along with PUCCH, PDCCH, PUSCH, or PDSCH to enable the base station to perform channel state estimation and correlation demodulation. SRS can be transmitted periodically or aperiodically to enable the base station to perform channel state estimation in order to support uplink-dependent channel scheduling and link adaptation.

[0112] Generally, channel measurements are performed through multiple ports. Typically, each port corresponds one-to-one with a reference signal. Reference signals from different ports can be transmitted using the same communication resources or different communication resources. When transmitting reference signals from multiple ports (e.g., CSI-RS) using the same communication resources (e.g., time-frequency resources), to distinguish the reference signals from different ports at the receiving end, the reference signals on each port are transmitted using orthogonal code division multiplexing of the same reference signal sequence, or different reference signal sequences are used for each port.

[0113] According to some embodiments, the communication system is an OFDM-based communication system, and the communication resources correspond to subcarriers. This will be described in detail below; however, it should be understood that the implementations described below can be applied equally to other types of communication resources. As an example, an OFDM-based non-orthogonal multiple access (NOMA) communication system can also be used.

[0114] In embodiments of this disclosure, the reference signal can be a CSI-RS / SRS, a reference signal specifically used for channel estimation; or a DMRS, a reference signal interpolated into the data for demodulation (which can be interpolated more sparsely and less frequently than existing ones). The receiver can use the DMRS on a subset of subcarriers to obtain the channel on other subcarriers carrying the data and use it for demodulation. Of course, depending on the specific communication system being applied, the reference signal can also be other types of reference signals.

[0115] System Configuration

[0116] Figure 5 A schematic diagram of a communication system 0200 according to an embodiment of the present disclosure is shown. The communication system 0200 may include a communication device 0210 and a communication device 0220 that can wirelessly communicate with each other. Although Figure 5 The diagram shows a communication device 0210 and a communication device 0220 communicating, but the communication device 0210 can communicate with multiple communication devices 0220, and the communication device 0220 can communicate with multiple communication devices 0210 (e.g., in the case of multi-point collaboration).

[0117] The communication device 0210 may include electronic device 0211 and antenna 0213. Furthermore, the communication device 0210 may also include other components not shown, such as a radio frequency link, baseband processing unit, network interface, processor, memory, controller, etc. Electronic device 0211 may be associated with antenna 0213. For example, electronic device 0211 may be directly or indirectly (e.g., possibly connected to other components in between) connected to antenna 0213, transmitting and receiving radio signals via antenna 0213.

[0118] Electronic device 0211 may include processing circuitry 0212. Furthermore, electronic device 0211 may also include input / output interfaces and memory, etc. The processing circuitry 0212 in electronic device 0211 can output signals (digital or analog) to other components in communication device 0210, and can also receive signals (digital or analog) from other components in communication device 0210. In addition, the processing circuitry 0212 can also control some or all of the operation of other components in communication device 0210.

[0119] The processing circuit 0212 can be in the form of a general-purpose processor or a special-purpose processing circuit, such as an ASIC. For example, the processing circuit 0212 can be constructed from circuitry (hardware) or a central processing unit (such as a central processing unit (CPU)). Furthermore, the processing circuit 0212 can carry a program (software) for making the circuitry (hardware) or the central processing unit function. This program can be stored in memory (such as in a communication device 0210 or electronic device 0211) or in an externally connected storage medium, and can be downloaded via a network (such as the Internet).

[0120] Although Figure 5 The diagram shows electronic device 0211 separated from antenna 0213, but electronic device 0211 can also be implemented to include antenna 0213. Furthermore, electronic device 0211 can also be implemented to include one or more other components of communication device 0210, or electronic device 0211 can be implemented as communication device 0210 itself. In practical implementation, electronic device 0211 can be implemented as a chip (such as an integrated circuit module comprising a single wafer), a hardware component, or a complete product.

[0121] Communication device 0220 may include electronic device 0221 and antenna 0223, and electronic device 0221 includes processing circuitry 0222. Furthermore, the above description of the structure of communication device 0210 also applies to communication device 0220, and will not be repeated here.

[0122] The communication system 0200 can be a cellular communication system, a machine-type communication (MTC) system, an ad hoc network, or a cognitive radio system (e.g., IEEE P802.19.1a and a spectrum access system (SAS)).

[0123] Communication device 0210 can be implemented as a base station (BS), small cell, Node B, e-NodeB (eNB), g-NodeB (gNB), relay, etc. in a cellular communication system; a terminal device in a machine-type communication system; a sensor node in an ad hoc network; or a coexistence manager (CM) or SAS in a cognitive radio system. For example, communication device 0210 can preferably be implemented as any type of node gNB, such as a macro gNB (associated with a macro cell) and a small gNB (associated with a small cell). A small gNB can be a gNB covering a cell smaller than a macro cell, such as a pico gNB, micro gNB, and femtocell gNB. Alternatively, communication device 0210 can be implemented as any other type of base station, such as an eNB, Node B, and base transceiver station (BTS). Communication device 0210 may include: a subject configured to control wireless communication (also called a base station device); and one or more remote radio heads (RRHs) located at a different location from the subject. In addition, the various types of terminals described later can all function as communication devices 0210 by temporarily or semi-persistently performing base station functions.

[0124] Communication device 0220 can be implemented as a terminal device or user equipment (UE). For example, communication device 0220 can be implemented as a mobile terminal (such as a smartphone, tablet PC, laptop PC, portable gaming terminal, portable / dongle-type mobile router, and digital camera device), drone, or vehicle terminal (such as a car navigation device). Communication device 0220 can also be implemented as a terminal performing machine-to-machine (M2M) communication (also known as a machine-type communication (MTC) terminal). Furthermore, communication device 0220 can be a wireless communication module (such as an integrated circuit module comprising a single chip) installed on each of the aforementioned terminals. Communication device 0220 can also be implemented as a smart meter, smart home appliance, or a Geolocation Capability Object (GCO) or Citizens Broadband Radio Service Device (CBSD) in a cognitive radio system.

[0125] For simplicity, the processing of communication devices 0210 and 0220 will be described below assuming that communication device 0210 is a base station and communication device 0220 is a user equipment. Communication from communication device 0210 to communication device 0220 is referred to as downlink, and communication from communication device 0220 to communication device 0210 is referred to as uplink. Note that when communication device 0210 is not a base station and communication device 0220 is not a user equipment, such as in the case of proximity-based service communication between two user equipments or wireless communication between two base stations, communication devices 0210 and 0220 may also perform the processing described below. Furthermore, some or all of the processing performed by communication devices 0210 and 0220 described below may be performed by processing circuits 0212 and 0222, or may be performed by processing circuits 0212 and 0222 controlling other components in communication devices 0210 and 0220 and / or components in other devices.

[0126] Implementation of Electronic Devices

[0127] The electronic device described in this disclosure can also be implemented in various other ways. According to some embodiments, the processing circuitry of the electronic device may include various units to implement the embodiments according to this disclosure. For example, the processing circuitry of the electronic device at the receiver end may include various estimation units to implement the various estimation operations described herein. The processing circuitry of the electronic device at the transmitter end may include transmitting and receiving units to implement the various operations performed at the transmitter end as described herein.

[0128] Figure 6A An exemplary electronic device 600 for a receiver end is illustrated according to an embodiment of the present disclosure. In one embodiment, the electronic device 600 may be implemented as a receiver or part thereof, or may be implemented as a device or part thereof for controlling a receiver or otherwise associated with a receiver.

[0129] Figure 6A The illustrated electronic device 600 may include processing circuitry 601, which may refer to various implementations of digital circuitry systems, analog circuitry systems, or mixed-signal (a combination of analog and digital signals) circuitry systems that perform functions in a computing system. The processing circuitry may include, for example, circuitry such as integrated circuits (ICs), application-specific integrated circuits (ASICs), portions or circuitry of a single processor core, an entire processor core, a single processor, programmable hardware devices such as field-programmable gate arrays (FPGAs), and / or systems comprising multiple processors.

[0130] In one embodiment, the processing circuit 601 includes at least a channel state estimation unit 602 and a channel path state estimation unit 603. The various operations described below can be implemented by units 602 and 603 of the electronic device 600 or other possible units.

[0131] In one embodiment, the channel state estimation unit 602 can estimate the channel state on the communication resource carrying the reference signal based on the reference signal from the transmitter, and the channel path state estimation unit 603 can estimate the channel path state from the transmitter to the receiver using the estimated channel state of the communication resource. The corresponding estimation process will be described in detail below.

[0132] The processing circuitry may also include a unit for determining the channel state from the transmitter to the receiver on other communication resources using the estimated channel path conditions. Of course, such a unit may also be located outside the processing circuitry or the electronic equipment. The corresponding processing will be described in detail below.

[0133] Electronic device 600 may also include, for example, a communication unit 604 and a memory 605.

[0134] The communication unit 604 can be configured to communicate with the receiving end under the control of the processing circuit 601. In one example, the communication unit 604 can be implemented to include communication components such as the antenna array and / or radio frequency link described above. In one embodiment, the communication unit can provide the estimation results obtained in the processing circuit 601 to the base station electronic equipment. In one embodiment, the communication unit can also transmit and receive information for beamforming processing, and may even include a processing unit for performing beamforming processing. Of course, such a processing unit can be located outside the communication unit.

[0135] The communication unit 604 is drawn with a dashed line because it can also be located outside the electronic device 600.

[0136] Memory 605 can store various information generated by processing circuit 601 (e.g., information about beam training, information about target channel direction, and basic compensation phase information), programs and data for operation of electronic device 600, data to be transmitted by communication unit 604, etc. Memory 605 is drawn with dashed lines because it can be located either within processing circuit 601 or outside electronic device 600. Memory 605 can be volatile memory and / or non-volatile memory. For example, memory 605 can include, but is not limited to, random access memory (RAM), dynamic random access memory (DRAM), static random access memory (SRAM), read-only memory (ROM), and flash memory.

[0137] Figure 6BAn exemplary electronic device for a transmitter end is shown according to an embodiment of the present disclosure. Figure 6B The electronic device 610 shown can process circuit 611, which can be implemented in various ways as described above.

[0138] In one embodiment, the processing circuit 611 may include a transmitting unit 612 and a receiving unit 613. The various operations described below may be implemented by units 612 and 613 or other possible units.

[0139] In one embodiment, the transmitting unit 612 can transmit the reference signal to the receiver using some communication resources, and the receiving unit 613 can receive any information from the receiver regarding the estimation results, such as the estimated channel state, the estimated channel path condition, etc.

[0140] The electronic device 610 may also include, for example, a communication unit and a memory as described above.

[0141] It should be noted that the above-mentioned units are merely logical modules divided according to their specific functions, and are not intended to limit the specific implementation method. For example, they can be implemented in software, hardware, or a combination of both. In actual implementation, the above-mentioned units can be implemented as independent physical entities, or they can be implemented by a single entity (e.g., a processor (CPU or DSP, etc.), integrated circuit, etc.).

[0142] It should be noted that the arrangement of the above-described units is merely exemplary and not limited to the aforementioned situations. For example, considering that the estimation process can also be performed on both the receiver and transmitter sides, some functions of the estimation unit at the receiver end can also be at least partially distributed at the transmitter end, performing further calculations by receiving feedback information from the receiver. Furthermore, for example, the transmitting and receiving units at the transmitter end can also be arranged at the receiver end.

[0143] It should be noted that the transmitter and receiver mentioned above can correspond to various parties in a wireless communication system. For example, the transmitter can correspond to a base station, and the receiver can correspond to a user equipment; this operation is particularly applicable to downlink communication transmission. Similarly, the transmitter can correspond to a user equipment, and the receiver can correspond to a base station; this operation is particularly applicable to uplink communication transmission.

[0144] Transceiver Architecture and Configuration

[0145] Transceiver architectures based on millimeter-wave and massive MIMO antennas, such as... Figure 7 As shown, where N RF，t N RF，r N represents the number of RF links in the transmitter and the number of RF links in the receiver, respectively. t Nr These represent the number of antennas on the transmitter and the number of antennas on the receiver, respectively. The transmitter's analog beamforming module will... RF，t Data streams from each RF link are mapped to N t On the root transmitting antenna, the mapping matrix can be represented as F RF The matrix has a dimension of N. t ×N RF，t Similarly, the receiver will send N r Data from the root receiving antenna is mapped to N RF，r On a radio frequency link, the mapping matrix can be represented as W RF The matrix has a dimension of N. r ×N RF，r Since beamforming does not generate power gain, F RF W RF The magnitude of each column as a column vector should be normalized to 1.

[0146] Therefore, the mathematical model for transmitting and receiving signals can be expressed as follows:

[0147]

[0148] Where x and y are the transmit vector of the transmitter RF link and the receive vector of the receiver RF link, respectively, with vector dimensions N. RF，t ×1, N RF，r ×1. H is the channel matrix, with a matrix dimension of N. r ×N t n is the noise vector of the receiver antenna, with dimension N. r ×1.

[0149] Here, the equivalent baseband channel matrix is ​​defined as...

[0150]

[0151] The equivalent baseband channel matrix H is visible. BB The dimension is N RF，r ×N RF，t Its dimension is much smaller than the dimension N of the channel matrix H. r ×N t Therefore, to simplify the calculation, the estimated equivalent baseband channel matrix H will be used. BB Instead of the channel matrix H.

[0152] Here, the beamforming matrix can be represented as Therefore, the equivalent baseband channel matrix can be expressed as

[0153]

[0154] Note that each element in the matrix has the same form. The channel estimation proposed in this disclosure is performed on one of these elements, but it is applicable to elements at any position in the matrix.

[0155] Therefore, to make the following description clearer, we will assume H in the following description. BB The dimension is 1×1, which is the number of radio frequency links N between the transmitter and receiver. RF，t =N RF，r =1, at this time F RF W RF All of them degenerate into vectors, denoted here as f, w, and H. BB Degenerate into a scalar, denoted as H BB Furthermore, to simplify the explanation, the antenna arrays of the transmitter and receiver are assumed to be arranged with equal one-dimensional half-wavelength spacing in the following text. However, this method is still applicable to antennas with non-linear arrangements.

[0156] Millimeter Wave Multipath Channel Model and Simplified Channel Model

[0157] The channel model of a millimeter-wave multiple-input multiple-output system in a multipath frequency-selective fading channel can be expressed as follows:

[0158]

[0159] Where f represents the frequency, L is the number of paths in the channel, and α l θ rl θ tl , τ l Let represent the complex gain, angle of arrival, angle of departure, and propagation delay of the l-th path, respectively. a(θ) is the response vector of the antenna array, which can be expressed as:

[0160]

[0161] Where N is the number of antennas in the antenna array, and θ represents the angle of arrival or the angle of departure. This channel model is as follows: Figure 8 As shown, it can be understood as the sum of the responses of each path in the transmission channel, where each path includes parameters such as complex gain, angle of arrival, angle of departure, and transmission delay.

[0162] Now consider the representation of the equivalent baseband channel in an orthogonal frequency division multiplexing system under this model.

[0163]

[0164] Where k represents the subcarrier index and Δf represents the subcarrier frequency interval.

[0165] Based on this model, the intensity parameter β of the l-th path can be defined. l With delay parameter Δ l

[0166]

[0167] Δ l =-2πτ l Δf

[0168] Therefore, the equivalent baseband channel can be simplified to...

[0169]

[0170] Note β l Δ l None of them are related to k.

[0171] Meanwhile, due to the sparsity of the millimeter-wave channel after beamforming, the total number of paths L can be assumed to be very small. Therefore, it is only necessary to estimate L and β. l Δ l With l = 1, 2, ..., L, the equivalent baseband channel H of all subcarriers can be obtained. BB (k). This is the basic idea behind this publication.

[0172] The following will refer to Figure 9 To summarize channel estimation according to embodiments of the present disclosure, Figure 9 This is a channel estimation process according to embodiments of this disclosure. It should be noted that... Figure 9 The steps shown can be performed by either the receiver or the transmitter.

[0173] In step 901, a reference signal is transmitted. In the context of this specification, the reference signal may also be referred to as a pilot signal; these terms are interchangeable.

[0174] In embodiments of this disclosure, the distribution of the transmitted reference signal may differ significantly from conventional methods.

[0175] According to some embodiments, the reference signal can be deployed only on a portion of the communication resources of the communication system; and the reference signal can be transmitted to the receiver via that portion of the communication resources. For example, Figure 10 As shown, the reference signal may be distributed only on a portion of the communication resources of the communication system (such as the first frequency range), which is only a small part of the entire frequency range.

[0176] According to one embodiment, the reference signal may be distributed over communication resources in a first frequency domain range of the communication system, wherein the frequency domain resources of the communication system are divided into a plurality of orthogonal frequency domain ranges that include the first frequency domain range.

[0177] According to some embodiments, the communication system is an OFDM-based communication system, and the communication resources correspond to subcarriers. This will be described in detail below; however, it should be understood that the implementations described below can be applied equally to other types of communication resources.

[0178] Now, assuming the indices of all subcarriers in the communication band are 0, 1, ..., (K-1), where K is the total number of subcarriers, the subcarrier index of the pilot transmitted for each channel estimation can be expressed as:

[0179] k0+k′K p k′=0,1,…,(K s -1)

[0180] Where K p K represents the subcarrier index difference between adjacent reference signals. s Let k be the number of subcarriers containing the reference signal, and k0 be the minimum index of all subcarriers containing the reference signal.

[0181] In embodiments of this disclosure, the distribution interval of the transmitted reference signals may be significantly different from that of conventional methods.

[0182] According to one embodiment, the reference signal can be distributed at predetermined intervals in the frequency domain. Here, K p This corresponds to the predetermined interval. Frequency domain pilot interval K p The selection of parameters can affect the estimation performance of the above methods and can be set in various ways.

[0183] According to some embodiments, the predetermined interval can be determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system.

[0184] According to some embodiments, the number of subcarriers containing the reference signal can be determined based on the accuracy of the channel estimation and the total bandwidth of the first frequency domain range expected to be occupied by the subcarriers containing the reference signal.

[0185] The predetermined interval and the number of subcarriers are set with consideration of the channel estimation performance of the embodiments of this disclosure. An example of the setting of the predetermined interval and the number of subcarriers will be described in detail below.

[0186] In step 902, the channel state on the communication resource carrying the reference signal is estimated based on the received reference signal (pilot).

[0187] After the receiver receives the pilot signal transmitted by the transmitter, it can estimate the channel state information of the subcarrier (communication resource) of the transmitted pilot signal based on the received pilot signal.

[0188] Channel state information can be estimated in various ways. Here, we take the least squares criterion as an example; the estimation process can be expressed as follows:

[0189]

[0190] in This represents the channel estimation result, where s indicates the index is k0+k′K. p The values ​​of the pilot signals on the subcarriers are taken here, and for convenience, s = 1 for all subcarriers. Through the pilot transmission and channel estimation process described above, the channel state information obtained by the receiver is now...

[0191] In step 903, the channel path condition from the transmitter to the receiver is estimated using the estimated channel state of the communication resources.

[0192] According to some embodiments, channel path conditions may include the number of paths, the phase parameter of each path, and the strength parameter of each path. Of course, depending on the specific application environment, channel path conditions may also include other types of parameters.

[0193] Channel path condition estimation can be achieved using various suitable methods. The following will refer to... Figure 11 This describes channel path condition estimation according to some embodiments of the present disclosure.

[0194] In step 1001, the spectrum of the estimated channel state data of the subcarriers is obtained for use in estimating the number of paths and the phase parameters of each path.

[0195] It should be noted that in the following description, the path delay parameter is used as an example to illustrate the path phase parameter. However, it should be noted that the path phase parameter is not limited to the path delay parameter. It can also indicate other types of path phase-related parameters, as long as such parameters can be obtained from the spectrum.

[0196] According to some embodiments, the spectrum is obtained by performing a time-frequency transformation on data of the estimated channel states of the subcarriers. This time-frequency transformation can be performed using various suitable techniques, such as DFT, FFT, etc.

[0197] Specifically, previously obtained channel state estimation results can be used. Complete the estimation of the total number of paths L and the delay parameter Δ for each path. l Estimate the values ​​of l = 1, 2, ..., L.

[0198] According to the simplified channel model, it can be... Represented as

[0199]

[0200] According to the above formula, we can Consider it as the sum of L complex sinusoidal digital signals, where the digital frequency corresponding to the l-th path is K. p Δ l Therefore, it can be analyzed using the Discrete Fourier Transform (DFT). The spectrum is analyzed to determine the frequency components to estimate L, and the frequency corresponding to each frequency component is further extracted to estimate the delay parameter Δ for each path. l .

[0201] Preferably, to ensure computational efficiency, the Fast Discrete Fourier Transform (FFT) is used instead of the DFT. However, it should be understood that this is not necessary. If the computational efficiency of the DFT meets the requirements, there is no need to use the FFT to replace the DFT.

[0202] First, the computation length of the FFT needs to be determined. To ensure the accuracy of the spectrum obtained from the FFT, a 1024-point FFT is used here. Therefore, it is necessary to... Zero-padding is performed to ensure a total of 1024 points. Conversely, to reduce the FFT sidelobe effect caused by zero-padding, a window function needs to be added after zero-padding. Therefore, the data before performing the 1024-point FFT can be represented as follows:

[0203]

[0204] Where w(k′) is the window function used, the following explanation will take the selection of w(k′) as a Hamming window as an example.

[0205] It should be noted that the aforementioned zero-padding and windowing operations are merely exemplary. The spectrum-related operations described in this disclosure can also be performed without such operations or while still including other operations. Typically, the selection of spectrum-related operations in this disclosure depends on the desired spectral accuracy. Generally, if the spectral accuracy basically meets the requirements, the aforementioned windowing operation can be omitted.

[0206] In step 1002, the total number of paths and the phase parameters of each path are determined by analyzing the spectrum obtained after the transformation.

[0207] According to some embodiments, the frequency components are analyzed using a peak search method to determine the total number of paths.

[0208] According to some embodiments, the number of paths corresponds to the number of peaks in the spectrum of the data that are above a predetermined threshold, and the phase parameter of each path is determined based on the spectrum of the peak corresponding to that path.

[0209] According to some embodiments, during the determination of the number of paths L, an upper limit can be set for the total number of paths L, which can be set in any suitable manner. Due to the sparsity of millimeter-wave channels after beamforming, it is assumed here that L does not exceed 4, that is, at most 4 peaks appear in the spectrum. Then, a peak search threshold is set, and peaks in the spectrum with amplitudes exceeding the threshold can be identified as corresponding to a frequency component or a path.

[0210] This predetermined threshold can be set in any suitable manner. For example, it can be set based on prior knowledge or on some application parameters. According to some embodiments, the predetermined threshold is determined based on the number of subcarriers containing the reference signal and the signal-to-noise ratio at the receiver.

[0211] As an example, the threshold can be empirically set to...

[0212]

[0213] SNR represents the signal-to-noise ratio of the receiver.

[0214] If the peak value exceeding the threshold exceeds the upper limit of the set L, then L is taken as its upper limit value, and the largest L peak values ​​are used to estimate the delay parameters.

[0215] Figure 12 This example demonstrates a 1024-point FFT result with L=1. Because L=1, the FFT spectrum contains only a single peak. The FFT result of a noisy channel estimate will produce a noise-induced peak outside the main peak, but its amplitude is usually small and will not exceed a threshold. For a peak that exceeds the threshold, assume the corresponding FFT index is... The delay parameter of the path corresponding to this peak can be estimated as follows:

[0216]

[0217] Figure 13 An example of a 1024-point FFT result with L=3 is shown. The graph contains three correct peaks, and simultaneously, due to noise, one noise peak exceeding the threshold appears. However, since the amplitude of the noise peak is often small, simulations verify that even with the appearance of a noise peak, the estimation error of this method is only slightly affected. Furthermore, the probability of the noise peak appearing is very low.

[0218] In addition to using FFT or DFT, other signal spectrum analysis or frequency component extraction methods can also be used to estimate the number of paths and delay parameters.

[0219] In step 1003, path strength parameters for each channel path are estimated.

[0220] According to some embodiments, the strength parameter of each path is estimated based on the estimated channel state of the subcarrier, the number of paths, and the phase parameter of each path.

[0221] According to some embodiments, the intensity parameter of each path is estimated by solving a system of linear equations based on the estimated channel state of the subcarrier, the number of paths, the phase parameter of each path, and the intensity parameter of each path established according to the multipath channel model.

[0222] As an example, at least through the above method, the receiver estimates the total number of paths L and the delay parameter Δ. l Let l = 1, 2, ..., L. Then, the receiver will determine the values ​​based on L and Δ. l as well as The intensity parameter β for each path l Make an estimate.

[0223] Based on the simplified channel model, we can obtain information about β. l linear equation system

[0224]

[0225] in

[0226]

[0227] Based on this system of linear equations, its solution β can be estimated using the least squares method. l

[0228]

[0229] This yields the value of β l The estimate.

[0230] Note that the dimension of matrix E is K. s ×L, thus E H The dimension of E is L×L. Since the value of L is very small, the above process involves matrix E. H The computational complexity of the E inversion operation is also relatively low.

[0231] Here, the least squares method is used for β. l In addition to estimation, methods such as the minimum mean square error (MMSE) can be used to estimate forms of...

[0232] Hx = y

[0233] The method for solving the system of equations for β lAn estimation is performed, where H is a matrix, x and y are vectors, H and y are known, and x is the vector to be estimated.

[0234] It should be noted that any other suitable method can also be used for β. l Make an estimate.

[0235] In step 904, the channel state information of all subcarriers will be recovered.

[0236] According to some embodiments, the estimated channel path conditions from the transmitter to the receiver can be directly substituted into the corresponding signal model of the communication system to obtain channel state information on communication resources in other frequency domains.

[0237] As an example, the receiver uses the estimated total number of paths L and the path delay parameter Δ l With strength parameter β l The channel state information of all subcarriers can be recovered using the following formula.

[0238]

[0239] Therefore, by employing the improved channel estimation method of this disclosure, the channel state from all the transmitters to the receivers in other communication resource / frequency ranges can be recovered.

[0240] In embodiments of this disclosure, the setting of the predetermined interval of the reference signal and / or the number of subcarriers carrying the reference signal affects the channel estimation performance. In specific implementations, these can be set in various ways.

[0241] As an example, the parameter K corresponding to the predetermined interval p It can be set as follows.

[0242] Based on the delay parameter Δ l The estimation method has an estimable range of [missing information].

[0243]

[0244] Therefore, for the delay τ l It needs to meet the following requirements.

[0245]

[0246] To ensure Δ l K does not exceed the estimated range. p Need to meet

[0247]

[0248] Where σ maxLet K be the maximum delay spread of the channel, and Δf be the frequency domain spacing between adjacent communication resources in the communication system. The above equation gives K. p The upper bound of the value is determined by the maximum delay spread of the channel.

[0249] At the same time, due to the Δ corresponding to two adjacent points on the spectrum l The difference is

[0250]

[0251] K p The larger the value, the greater the Δ value corresponding to different paths in the 1024-FFT spectrum. l The higher the resolution, the better. Therefore, preferably, the maximum value of the interval can reach the reciprocal of the product of the maximum delay spread and the subcarrier interval.

[0252] The following will describe, for example, the setting of the number of subcarriers / pilots.

[0253] For example, in K p When the total number of pilots K is fixed, s As K increases, the estimation accuracy will also improve accordingly. This is because when K... s When the value is increased, the sidelobe effect caused by zero-padding in the 1024-point FFT decreases, and the main lobe width narrows, which will increase the total number of paths L and the path delay parameter Δ. l The estimation accuracy. In addition, in estimating the intensity parameter β... l The accuracy of the least squares estimation method used will also vary with K. s It increases with the increase of K. s Increasing the value will also increase the pilot overhead.

[0254] Conversely, if K s If the value is too small, the sidelobe amplitude corresponding to the peak of the FFT spectrum will be large and the main lobe width will be large, resulting in a large estimation error. Here, we assume that the number of FFT points used in path estimation is 2. n (1024-FFT corresponds to n=10), in order to ensure the estimation accuracy K s Should meet

[0255]

[0256] For example, if a 1024-FFT is used, at least K is required. s The value is 16.

[0257] In summary, regarding K p With K s The selection of K should first be based on the maximum delay spread of the channel and the subcarrier spacing. pThe upper bound is chosen, and a larger K is selected without exceeding the upper bound. p Furthermore, based on the selected number of FFT points, K is determined. s The lower bound is determined by considering both bandwidth and pilot overhead limitations, and K is chosen to be as large as possible based on this lower bound. s It can improve the accuracy of channel estimation.

[0258] The bandwidth occupied by the frequency band including the pilot is approximately K. p K s The bandwidth of each subcarrier, if in K s When taking the minimum value, K p K s If the bandwidth corresponding to each subcarrier still exceeds the expected total bandwidth, then it can be reduced by decreasing K. p The value of K makes p K s The bandwidth corresponding to each subcarrier is less than the expected total bandwidth.

[0259] Distribution of Reference Signals over Time and Frequency Resources

[0260] The above mainly describes the distribution of the reference signal in the frequency domain. It should be noted that, in addition to frequency domain resources, the reference signal can also be distributed in the time domain resources in a specific way.

[0261] According to some embodiments, the reference signal can be distributed across at least one time slot, thereby enabling the joint estimation of the channel state of a subcarrier containing the reference signal using the reference signal distributed across at least one time slot.

[0262] According to some embodiments, the reference signal is distributed across the entire transmission frequency band in a specific time slot, and is distributed only within a portion of the frequency band in other time slots besides the specific time slot; and wherein the number of paths and the phase parameter of each path are estimated using the reference signal in the specific time slot, and the intensity parameter of each path is updated using the estimated number of paths and the phase parameter of each path in the time slot immediately following the specific time slot.

[0263] In one implementation, the number of paths, as well as the phase and intensity parameters of each path, can be estimated simultaneously within a specific time slot. In the next adjacent time slot, the intensity parameters of the path in the next time slot can be estimated using the estimation results of the number of paths and the path phase parameters of the previous time slot.

[0264] Therefore, the path parameter report can report the number of paths, phase, and intensity after the first time slot is measured. Subsequent reports within the predetermined time period can only report the intensity. The base station can then combine the previously reported number of paths and phase to restore the current channel state.

[0265] According to some embodiments, the reference signal is distributed only within a portion of the frequency band in all time slots.

[0266] According to some embodiments, for even-numbered and odd-numbered time slots, the reference signal is alternately distributed across a lower frequency half-band or a higher frequency half-band; and

[0267] Specifically, the number of paths and the phase parameter of each path are estimated using a reference signal in one of the even-numbered and odd-numbered time slots, and the intensity parameter of each path is updated using the estimated number of paths and the phase parameter of each path in the other of the even-numbered and odd-numbered time slots following that time slot.

[0268] In one implementation, the number of paths, as well as the phase and intensity parameters of each path, can be estimated simultaneously in one of the even and odd time slots. In the other of the even and odd time slots following this time slot, the estimation results of the number of paths and the path phase parameters of the previous time slot can be used to estimate the intensity parameters of the paths in that other time slot.

[0269] The following will serve as an example to describe how the reference signal is distributed across time-frequency resources. This distribution can also be referred to as a mapping from the reference signal to time-frequency resources.

[0270] The following exemplifies a reference signal-to-time-frequency resource mapping method according to an embodiment of the present disclosure, with a single-layer data transmission mode. The following mapping method is applicable to the design of reference signals for channel estimation in millimeter-wave OFDM systems, such as CSI-RS, DM-RS, and uplink sounding reference signals (SRS).

[0271] Figure 14 An embodiment of the present disclosure is shown, which can be represented as follows:

[0272]

[0273]

[0274]

[0275]

[0276]

[0277]

[0278] In this method, pilots are distributed across only a portion of the frequency band in all time slots. In this example, in even-numbered time slots, pilots are distributed across the lower half of the bandwidth; in odd-numbered time slots, pilots are distributed across the higher half of the bandwidth. The pilot overhead in this example is only one-quarter of that in conventional single-layer transmission.

[0279] Under this reference signal mapping method, the receiver can recover the full-band channel state information in each time slot using pilots distributed only on half the bandwidth. Furthermore, the receiver can also perform joint channel estimation using pilots from multiple time slots. For example, when the channel time-varying nature is within a controllable range, the simplest method is for the receiver to average the channel estimation results from two adjacent time slots. Because there are differences between the theoretical model and the actual channel, transmitting pilots only on half the bandwidth will introduce errors in the estimation of the other half of the bandwidth where pilots are not transmitted. Jointly estimating the channel using pilots from two adjacent time slots can compensate for this error, thereby improving the estimation accuracy.

[0280] Figure 15 An embodiment of the present disclosure is shown, which can be represented as follows:

[0281]

[0282]

[0283]

[0284]

[0285]

[0286]

[0287] In this mapping method, pilots for some time slots are distributed across the entire frequency band, while pilots for other time slots are distributed across a portion of the frequency band. In this example, pilots are distributed across the entire frequency band in even-numbered time slots and across half the frequency band in odd-numbered time slots. The pilot overhead in this example is three-eighths of the pilot overhead of conventional single-layer transmission.

[0288] Similar to the first example, using the reference signal mapping method in this example, the receiver can perform channel estimation using only pilots within a single time slot, or it can estimate the channel using multiple time slots. For example, it can be assumed that the number of paths and the path delay remain constant between every two time slots (if a high-speed mobile user moves at a speed of 100 m / s, and each time slot is 0.5 ms, then the user moves 0.1 m between two time slots. Based on the propagation speed of electromagnetic waves, the change in path delay after two time slots is less than 1 ns, which has a negligible impact on the delay parameters), and only the intensity parameters of each path will change. In this way, the receiver can use pilots distributed across the entire frequency band in even-numbered time slots to estimate the number of paths and the delay parameters, and then use the previously obtained number of paths and delay parameters in subsequent odd-numbered time slots to estimate only the intensity parameters of each path. This method can also be applied to the mapping method in the first example.

[0289] Channel Estimation Feedback

[0290] After performing the channel estimation described above, the receiver can feed back the obtained channel estimation results, such as channel path conditions, to the transmitter so that the transmitter can perform subsequent processing, such as allocating resources for subsequent data transmission or for demodulation processing.

[0291] Alternatively, according to some embodiments, the estimated parameters can be fed back to the transmitter, which then performs channel path condition estimation.

[0292] In existing communication systems, such as LTE, after the User Equipment (UE) completes channel estimation based on the Channel State Information Reference Signal (CSI-RS), it can feed back the channel state information (CSE) of each subcarrier or other channel-related information to the base station. The base station then determines relevant parameters such as modulation scheme, coding scheme, time-frequency resource scheduling scheme, and precoding matrix and transmission mode for the MIMO antenna system in single-user or multi-user scenarios based on the channel information, and notifies the UE of this information via signaling. However, if the UE were to feed back the CSE information of each subcarrier to the base station, the amount of information required would be large, resulting in significant additional communication overhead. Therefore, in LTE, the UE calculates the Channel Quality Identifier (CQI), Precoding Matrix Index (PMI), and Rank Identifier (RI) based on the estimated channel and feeds this information back to the base station. While this reduces additional communication overhead, the base station cannot obtain accurate downlink channel state information, and due to limitations in the UE's data processing capabilities and device power consumption, the fed-back CQI, PMI, and RI information can only be obtained through rough estimation.

[0293] According to the embodiments of this disclosure, several parameters involved in the channel estimation method proposed in this disclosure are fed back, including the total number of paths, the delay of each channel path, and the strength parameters of each channel path, so that the complete channel state information can be represented by several parameters. Then, the base station can directly calculate the complete channel state information based on the parameters and determine the optimal transmission mode (including the modulation mode, time and frequency resource scheduling, and precoding matrix of multiple input multiple output antennas mentioned above).

[0294] It should be noted that the channel parameters related to channel estimation involved in this disclosure are exemplary. In some applications, they can replace existing channel-related parameters, such as CQI, PMI, RI, etc., and be fed back and processed. In other applications, they can coexist with existing channel-related parameters, such as CQI, PMI, RI, etc., and can serve as a useful supplement to existing channel-related parameters.

[0295] Depending on the transmission method of the reference signal, the channel estimation parameters can be fed back using a corresponding transmission method. The following will exemplarily describe the feedback of channel estimation parameters obtained through CSI-RS.

[0296] As an example, if the UE's channel estimation is performed based on CSI-RS, the UE still needs to provide channel information feedback to the base station after the channel estimation. Here, the UE can determine this by specifying the number of transmission paths L and the path delay parameter β. l and path strength parameter Δ l The feedback requires a total of 2L+1 parameters. After receiving 2L+1 parameters, the base station can recover the channel of all subcarriers.

[0297] Example of feedback information encoding method: First, set the maximum value of L to L max Assume L max If the value is ≤4, then 2 bits can be allocated for L in the control channel resources fed back by the UE to the base station. The UE uses these 2 bits to feed back L. Then, in subsequent uplink control channel resources, L Δ... l Provide feedback, due to Δ l For a real number, it can be represented by L 8-bit numbers δ l Represents each Δ l The value of is also transmitted, along with a 3-bit amplitude factor r, for each Δ. l It can be calculated from a fixed-point number and an amplitude factor, such as Therefore, L Δ feedbacks are provided. l The required uplink control channel resources total 8L+3 bits. Finally, in the subsequent uplink control channel resources, L β bits are allocated... l Provide feedback. Due to β lFor complex numbers, the real and imaginary parts need to be transmitted separately. The encoding method for the real or imaginary part is the same as that for Δ. l Similarly, a total of 2L 8-bit numbers and 1 3-bit amplitude factor are needed, therefore L beta numbers are fed back. l The required uplink control channel resources total 16L+3 bits. Under this coding scheme, transmitting all 2L+1 parameters requires a total of 24L+8 bits, or 3L+1 bytes.

[0298] Due to sparsity, the value of L is very small, which allows the UE to feed back the complete subcarrier channel to the transmitter with very little channel information feedback overhead.

[0299] The distribution of CSI-RS required to complete the above process can also be distributed only in a portion of the overall frequency band. The UE estimates the 2L+1 parameters required for feedback based on the CSI-RS in the portion of the frequency band, and the base station recovers the channel of the entire frequency band based on these 2L+1 parameters.

[0300] Feedback of channel estimation results can be achieved through various devices.

[0301] According to some embodiments, the receiver further includes a radio frequency link and a transceiver antenna, the radio frequency link and the transceiver antenna being configured to feed back channel state information on communication resources in the first frequency domain range estimated by the processing circuit to the transmitter.

[0302] According to some embodiments, the receiver's electronic equipment further includes a transceiver antenna configured to feed back the estimated channel path conditions to the transmitter.

[0303] After the transmitter receives the feedback channel information and restores the channels of each subcarrier, it can determine the relevant transmission parameters based on the channel state and feed them back to the UE. For example, one or more parameters such as modulation scheme, coding scheme, time-frequency resource scheduling, precoding matrix indication, rank indication, and channel quality indication can be determined from the subcarrier channel. The transmitter then feeds back the above information to the UE through the downlink control channel.

[0304] It should be pointed out that it is not necessary to restore the entire frequency band before making a decision. For example, based on the utilization of frequency band resources, only the available frequency bands can be restored for frequency resource selection.

[0305] According to some embodiments, the receiver's transceiver antenna is further configured to receive transmission resource allocation information from the transmitter, and the processing circuit is configured to control signal transmission and reception on the allocated transmission resources, wherein the transmission resources are determined based on the channel state of communication resources from the transmitter to the receiver in various frequency domain ranges. The transmission resource allocation information may include information such as resource location indication and modulation / coding scheme.

[0306] According to some embodiments, the communication resource frequency domain range of the communication system is located in the frequency band corresponding to millimeter waves or micrometer waves. Millimeter waves typically correspond to extremely high frequencies (EHF), 30-300 GHz, with wavelengths of 10-1 mm, while micrometer waves typically correspond to ultra-high frequencies, 300-3000 GHz, with wavelengths of 1-0.1 mm.

[0307] Simulation results

[0308] This section presents a simulation verification of channel estimation based on channel sparsity according to embodiments of this disclosure. The simulation parameters used are as follows: OFDM system bandwidth of 250MHz, number of subcarriers of 1024, and carrier frequency of 30GHz; transmitter and receiver antennas of 128 and 16 respectively, and RF links of 1 for both; the beam selection method used by the transceivers is based on the single-link-to-single-link gain maximization criterion, i.e.

[0309]

[0310] Where f and w are the beamforming vectors used by the receiver and transmitter, respectively, and they are selected from a column of the DFT matrix with dimensions of 128×128 and 16×16, respectively, with a magnitude of 1.

[0311] Figure 16 The image shows a comparison of channel estimation results based on traditional interpolation and sparse pilot channel estimation under a channel model with L=50 (before beamforming), where the pilot spacing K is... p =16, total number of pilots K s =32, meaning pilot signals are transmitted only on half the bandwidth. The results show that the interpolation method can only estimate half the channel bandwidth, and due to the sparse pilot distribution, the estimation results of the interpolation method have a large error. Meanwhile, the sparse pilot channel estimation method can more accurately recover the channel across the entire frequency band.

[0312] Similarly, in Figure 17 Simulation parameter K s =64, other parameters remain the same as Figure 9 The simulation is the same, except that pilots are transmitted across the entire frequency band. The results show that the interpolation method still cannot accurately estimate the channel due to the sparsity of the pilots. However, sparse pilot channel estimation can...Figure 9 To obtain a more accurate estimate based on this, the reason is K s It has doubled in size.

[0313] also, Figure 18 Simulation results for the mean square error (MSE) of sparse pilot channel estimation and interpolation channel estimation are presented, where MSE is defined as...

[0314]

[0315] in This is the channel estimation result for the k-th subcarrier. (From...) Figure 18 It can be seen that, under the same pilot overhead, the MSE performance of sparse pilot channel estimation is significantly better than that of interpolation methods. When K s When the SNR is low, interpolation methods cannot effectively recover the channel, while sparse pilot channel estimation can still achieve good MSE performance under these conditions. Furthermore, it can be seen that sparse pilot channel estimation still achieves good MSE performance even with low SNR, indicating that this method has good resistance to noise effects.

[0316] Compared with conventional interpolation methods, the channel estimation according to the embodiments of this disclosure significantly reduces pilot overhead.

[0317] Furthermore, according to embodiments of this disclosure, the transmitter can transmit pilot patterns with a sparser distribution. According to embodiments of this disclosure, the transmitter can transmit pilots only in a portion of the communication resources / frequency range, instead of transmitting pilots in the entire communication resources / frequency range.

[0318] Furthermore, the embodiments according to this disclosure have low computational complexity and are highly feasible.

[0319] The foregoing has described various exemplary electronic devices according to embodiments of the present disclosure. It should be noted that embodiments of the present disclosure may also relate to methods for a receiver and a transmitter in a wireless communication system.

[0320] Another aspect of this disclosure relates to a method for a receiver in a wireless communication system. According to some embodiments, the method includes estimating channel states on communication resources carrying the reference signal based on a reference signal from a transmitter, wherein the reference signal is distributed over communication resources in a first frequency domain range of the communication system, the frequency domain resources of the communication system being divided into a plurality of orthogonal frequency domain ranges encompassing the first frequency domain range; and estimating channel path conditions from the transmitter to the receiver using the estimated channel states of the communication resources. The channel states from the transmitter to the receiver on communication resources in other frequency domain ranges can be derived from the estimated channel path conditions.

[0321] Another aspect of this disclosure relates to a method for a receiver in a wireless communication system. According to some embodiments, the method may include estimating channel states on communication resources carrying reference signals based on reference signals from a transmitter, wherein the reference signals are distributed in the frequency domain at predetermined intervals, and the predetermined intervals are determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system; and estimating channel path conditions from the transmitter to the receiver using the estimated channel states of the communication resources. The channel states from the transmitter to the receiver on other communication resources are derived from the estimated channel path conditions.

[0322] Another aspect of this disclosure relates to a method for a transmitter in a wireless communication system. According to some embodiments, the method may include determining that a reference signal will be deployed only on communication resources within a first frequency domain range of the communication system; and transmitting the reference signal to a receiver via the communication resources within the first frequency domain range. The frequency domain resources of the communication system are divided into a plurality of orthogonal frequency domain ranges encompassing the first frequency domain range. The channel path condition from the transmitter to the receiver is derived based on channel estimation on the communication resources within the first frequency domain range. The channel state from the transmitter to the receiver on communication resources in other frequency domain ranges is derived from the estimated channel path condition.

[0323] Another aspect of this disclosure relates to a method for a transmitter in a wireless communication system. According to some embodiments, the method may include transmitting a reference signal to a receiver in the wireless communication system via communication resources. The reference signal is distributed in the frequency domain at predetermined intervals, and the predetermined intervals are determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system. The channel state on the communication resources carrying the reference signal is estimated based on the reference signal from the transmitter. The channel path condition from the transmitter to the receiver is estimated using the estimated channel state on the communication resources. The channel state from the transmitter to the receiver on other communication resources is derived from the estimated channel path condition.

[0324] It should be noted that these method embodiments can be implemented in any manner. For example, they can be implemented in any suitable way by corresponding devices, circuits, apparatuses, etc. in the receiver and / or transmitter. The specific implementation methods will not be described here.

[0325] It should be understood that the operation or function of these electronic devices can be combined with each other to achieve more or fewer operation or function than described. The operational steps of the methods can also be combined with each other in any suitable order to similarly achieve more or fewer operation than described.

[0326] The following examples illustrate various application instances of channel estimation according to embodiments of this disclosure.

[0327] First Application Example

[0328] According to embodiments of this disclosure, the channel estimation technique of this disclosure can be applied in combination with beamforming processing in a wireless communication system.

[0329] According to some embodiments, the communication system is a millimeter-wave communication system. The electronic device at the receiver end is implemented as a user equipment or a base station, and also includes a transceiver antenna. The transceiver antenna includes multiple antennas and a phase shifter coupled to each antenna. The processing circuit controls the phase setting of the phase shifter to form a beam pointing towards the transmitter based on the beam scanning result between the receiver and the transmitter. The transceiver antenna uses the beam to receive a reference signal from the transmitter end for the processing circuit to perform channel estimation.

[0330] For example, in such application scenarios, the reference signal can be distributed on communication resources as a channel state information reference signal (CRI-RS).

[0331] For example, in extremely high frequency bands such as millimeter waves, it is necessary to simulate beam pairs for auxiliary communication scenarios (channel sparsity caused by high frequency). The method disclosed in this paper is used to perform channel estimation within the beam pair, that is, first perform beam scanning and pairing, and then estimate the channel (equivalent baseband channel HBB) within the paired beam.

[0332] The following will refer to the appendix Figures 19-22 This example application scenario briefly describes the basic operations, which mainly involve downlink and uplink operations. Here, gNB refers to, for example, a base station, and UE refers to, for example, a user equipment. Depending on the specific signal flow direction, they can respectively indicate the transmitter and / or receiver. It should be noted that this is merely exemplary; the transmitter and receiver can have various other implementations, as long as they can interact and communicate with each other.

[0333] In such application scenarios, different processing methods can be adopted according to the symmetry of the uplink and downlink channels.

[0334] According to some embodiments, in asymmetric situations, such as uplink / downlink channel asymmetry or uplink / downlink beampair asymmetry in an FDD system, a first device (e.g., a transmitter) transmits reference signals on a number of concentrated sub-bands, a second device (e.g., a receiver) measures the reference signals in the sub-bands, determines and feeds back path parameters, and the first device recovers the channel on other frequency bands from the first device to the second device based on the fed-back path parameters.

[0335] According to some embodiments, in a symmetrical case, such as a TDD system with symmetrical uplink and downlink channels or symmetrical uplink and downlink beam pairs, a first device (e.g., a transmitter) transmits reference signals on a set of sub-bands, a second device (e.g., a receiver) measures the reference signals of the sub-bands, the second device determines and recovers, based on path parameters, a channel from the first device to the second device that includes a frequency band different from the set of sub-bands, and determines, based on channel reciprocity, a channel from the second device to the first device that includes other frequency bands.

[0336] Figure 19 An application example of downlink CSI-RS transmission in an exemplary asymmetric scenario is shown.

[0337] First, the base station transmits multiple transmit beams, and the user equipment uses multiple receive beams to receive them in order to complete the downlink beam scan and determine the downlink beam pair containing the strongest base station transmit beam and the corresponding user receive beam.

[0338] This determination process can be achieved using various known beam pair scanning methods. For example, it can be achieved using various beamforming training methods, such as the beamforming training methods described above, and therefore will not be described in detail here.

[0339] Then, by using the determined transmit and receive beam pairs, the base station and user equipment can perform an embodiment according to this disclosure to make appropriate channel estimation for subsequent data transmission.

[0340] The base station determines to use the strongest transmit beam for transmission, carrying the downlink reference signal on communication resources within the first frequency domain of the communication system. Thus, the beamformed reference signal is transmitted downlink to the user side.

[0341] The physical resources where the reference signal is located can be flexibly configured in various ways. For example, they can be determined based on factors such as resource availability. This eliminates the need to place the reference signal at a fixed resource location as in existing technologies, thus enabling greater flexibility in resource utilization.

[0342] Communication resources in the first frequency domain can be utilized to transmit downlink reference signals from the base station to the user terminal, such as... Figure 19The dashed lines in the diagram illustrate this. It should be noted that, in this flexibly configured example, the communication resources within the first frequency domain range can be communicated to the user in various ways. For example, the user can be informed via broadcast messages, dedicated messages, or other notification information.

[0343] As another embodiment, the physical resources where the reference signal is located can also be pre-fixed through a communication protocol. In this case, the physical resources do not need to be notified to the user, because the user already knows this in advance.

[0344] The user equipment can receive downlink reference signals on communication resources in the first frequency domain range using the strongest receiving beam, and estimate the channel state of the communication resources in the first frequency domain range. This estimation operation can be performed as described in the embodiments of this disclosure above.

[0345] User equipment can determine downlink path parameters based on the estimated channel state of communication resources in the first frequency domain range, for example, as described in the embodiments of this disclosure above, by using the estimated channel state of communication resources in the first frequency domain range to estimate the channel path conditions from the base station to the user side, thereby determining the downlink path parameters.

[0346] Then, the user side can notify the base station side of the downlink path parameters.

[0347] It should be noted that the above operations are exemplary. According to another embodiment, the determination of downlink path parameters can also be performed at the base station side, such as... Figure 19 As shown by the dashed line.

[0348] In this case, the user side can notify the base station side of the estimated channel state of the communication resources in the first frequency domain range. The base station side can then determine the downlink path parameters based on the estimated channel state of the communication resources in the first frequency domain range. For example, as described in the embodiments of this disclosure above, the estimated channel state of the communication resources in the first frequency domain range can be used to estimate the channel path condition from the base station to the user side, thereby determining the downlink path parameters.

[0349] The base station restores the downlink channel state of communication resources in other frequency domains of the communication system based on the determined downlink path parameters, as described in the embodiments of this disclosure above.

[0350] The base station can determine downlink resource scheduling, modulation and coding schemes, baseband precoding, MU-MIMO user pairing, and other multi-antenna processing for data transmission to the user equipment based on the downlink channel status of communication resources in various frequency domains of the communication system. It then provides the determined downlink resource indications to the user side. Specifically, the base station may perform at least one of the following: identify the resource block corresponding to the subcarrier with the larger amplitude from the equivalent baseband channels on each recovered subcarrier, schedule the resource block to the user equipment for transmission service, determine a suitable modulation and coding scheme based on the equivalent baseband channel of the resource block, determine a matching downlink precoding matrix based on the equivalent baseband channel of the resource block, and identify other user equipment with good orthogonality of the equivalent baseband channels on the resource block for MU-MIMO transmission.

[0351] Therefore, the base station can transmit downlink data through downlink beam pairs.

[0352] Figure 20 An application example of determining the uplink channel using uplink SRS transmission in an exemplary asymmetric scenario is shown.

[0353] First, the user equipment transmits multiple transmit beams, and the base station uses multiple receive beams to receive them in order to complete the uplink beam scan and determine the uplink beam pair containing the strongest user transmit beam and the corresponding base station receive beam.

[0354] This determination process can be achieved using various known beamforming methods. For example, it can be achieved using various beamforming training methods, such as those described above, and therefore will not be described in detail here.

[0355] Then, by using the determined transmit and receive beam pairs, the user side and the base station can perform appropriate channel estimation according to embodiments of this disclosure for subsequent data transmission.

[0356] The user determines to use the strongest transmit beam for transmission, carrying the uplink reference signal on communication resources within the first frequency domain of the communication system. Thus, the beamformed reference signal is transmitted uplink to the base station.

[0357] As mentioned above, communication resources in the first frequency domain range can be notified from the base station to the user terminal, such as... Figure 20 The dotted line indicates this. For example, the user can be informed via broadcast information or other notification information. As another embodiment, the physical resources where the reference signal is located can also be pre-fixed via a protocol. In this case, the physical resources do not need to be notified to the user because the user is already aware of this.

[0358] The base station can receive uplink reference signals on communication resources in the first frequency domain range using the strongest receiving beam, and estimate the channel state of the communication resources in the first frequency domain range. This estimation operation can be performed as described in the embodiments of this disclosure above.

[0359] The base station can determine uplink path parameters based on the estimated channel state of communication resources in the first frequency domain range. For example, as described in the embodiments of this disclosure above, the base station can use the estimated channel state of communication resources in the first frequency domain range to estimate the channel path conditions from the base station to the user side, thereby determining the uplink path parameters.

[0360] Then, the base station can restore the uplink channel state of communication resources in other frequency domain ranges in the communication system based on the determined uplink path parameters, as described in the embodiments of this disclosure above.

[0361] According to other embodiments, the determination of uplink path parameters and / or the determination of uplink channel states of communication resources in other frequency domains can also be performed on the user side, as described above. This typically depends on the processing capabilities, operating modes, etc. of the base station and the user side.

[0362] The base station can determine uplink resource scheduling, scheduling coding scheme, baseband precoding, MU-MIMO user pairing, and other multi-antenna processing for data transmission to the user equipment based on the uplink channel status of communication resources in various frequency domains of the communication system. It also provides uplink resource indications to the user side.

[0363] Therefore, users can transmit uplink data through uplink beam pairs.

[0364] Figure 21 This example illustrates an application instance where the uplink channel is determined via uplink SRS transmission in a symmetrical scenario.

[0365] First, the user transmits multiple transmit beams, and the base station uses multiple receive beams to receive them, thus completing an uplink beam scan to determine the uplink beam pair containing the strongest user transmit beam and the corresponding base station receive beam. In the presence of symmetry, this allows for the corresponding determination of the downlink beam pair, namely the user receive beam and the base station transmit beam, which are identical to the user transmit beam and the base station receive beam, respectively.

[0366] It should be noted that the determination of the transmit and receive beam pairs can also be achieved in other ways. For example, alternatively, it can be initiated by the base station side, such as... Figure 21As shown by the dashed lines in the diagram. Specifically, the base station transmits multiple transmit beams, and the user uses multiple receive beams to complete the downlink beam scan, determining the downlink beam pair containing the strongest base station transmit beam and the corresponding user receive beam. Due to channel symmetry, the uplink beam pair is the same as this downlink beam pair, thereby correspondingly determining the base station receive beam and the user transmit beam, which are the same as the base station transmit beam and the user receive beam, respectively.

[0367] This determination process can be achieved using various known beamforming methods. For example, it can be achieved using various beamforming training methods, such as those described above, and therefore will not be described in detail here.

[0368] Then, by using the determined transmit and receive beam pairs, the user side and the base station can perform appropriate channel estimation according to embodiments of this disclosure for subsequent data transmission.

[0369] The user determines to use the strongest transmit beam for transmission, carrying the uplink reference signal on communication resources within the first frequency domain of the communication system. Thus, the beamformed reference signal is transmitted uplink to the base station.

[0370] As described above, communication resources within the first frequency domain range can be notified to the user from the base station. For example, this can be done through broadcast information or other notification methods. Alternatively, the physical resources containing the reference signal can be pre-defined via a protocol; in this case, the physical resources do not need to be notified to the user, as the user is already aware of this.

[0371] The base station can receive uplink reference signals on communication resources in the first frequency domain range using the strongest receiving beam, and estimate the channel state of the communication resources in the first frequency domain range. This estimation operation can be performed as described in the embodiments of this disclosure above.

[0372] The base station can determine uplink path parameters based on the estimated channel state of communication resources in the first frequency domain range. For example, as described in the embodiments of this disclosure above, the base station can use the estimated channel state of communication resources in the first frequency domain range to estimate the channel path conditions from the user side to the base station, thereby determining the uplink path parameters.

[0373] Then, the base station can restore the uplink channel state of communication resources in other frequency domain ranges in the communication system based on the determined uplink path parameters, as described in the embodiments of this disclosure above.

[0374] According to other embodiments, the determination of uplink path parameters and / or the determination of uplink channel states for communication resources in other frequency domains can also be performed on the user side, as described above. This typically depends on the processing capabilities, operating modes, etc., of both the base station and the user side.

[0375] The base station can determine uplink resource scheduling, scheduling coding scheme, baseband precoding, MU-MIMO user pairing, and other multi-antenna processing for data transmission to the user equipment based on the uplink channel status of communication resources in various frequency domains of the communication system. It also provides uplink resource indications to the user side.

[0376] Therefore, users can perform uplink data transmission through the determined beam pair.

[0377] Figure 22 This example demonstrates an application instance of obtaining the downlink channel via uplink SRS transmission in a symmetrical scenario.

[0378] First, transmit and receive beam pairs can be determined by leveraging symmetry. Specifically, the base station transmits multiple transmit beams, and the user receives them using multiple receive beams to complete a downlink beam scan, identifying the downlink beam pair containing the strongest base station transmit beam and the corresponding user receive beam. Due to channel symmetry, the uplink beam pair is identical to this downlink beam pair. Therefore, the base station receive beam and the user transmit beam can be determined accordingly, and they are identical to the base station transmit beam and the user receive beam, respectively.

[0379] It should be noted that the determination of the transmit and receive beam pairs can also be achieved in other ways. For example, alternatively, it can be initiated by the user side, such as... Figure 22 As shown by the dashed lines, the user transmits multiple transmit beams, and the base station uses multiple receive beams to receive them, thus completing an uplink beam scan to determine the uplink beam pair containing the strongest user transmit beam and the corresponding base station receive beam. In the presence of symmetry, this allows for the corresponding determination of the downlink beam pair, namely the user receive beam and the base station transmit beam, which are identical to the user transmit beam and the base station receive beam, respectively.

[0380] This determination process can be achieved using various known beamforming methods. For example, it can be achieved using various beamforming training methods, such as those described above, and therefore will not be described in detail here.

[0381] Then, by using the determined transmit and receive beam pairs, the user side and the base station can perform appropriate channel estimation according to embodiments of this disclosure for subsequent data transmission.

[0382] Relying on the beam / channel symmetry / reciprocity of the communication system, the downlink channel state can be estimated simultaneously with uplink channel estimation, further simplifying the estimation process. For example, it can be obtained by referring to... Figure 21 The uplink channel estimation is performed simultaneously with the downlink channel estimation.

[0383] Specifically, after the base station can restore the uplink channel state of communication resources in other frequency domains of the communication system based on the determined uplink path parameters, the base station can also determine the downlink channel state of communication resources in each frequency domain of the communication system based on channel symmetry and the restored uplink channel state of communication resources in each frequency domain of the communication system.

[0384] The base station can determine downlink resource scheduling, scheduling coding scheme, baseband precoding, MU-MIMO user pairing, and other multi-antenna processing for data transmission to the user equipment based on the downlink channel status of communication resources in various frequency domains of the communication system. It also provides downlink resource indications to the user side.

[0385] Therefore, the base station can perform downlink data transmission through the determined beam pairs.

[0386] It should be noted that the above-mentioned symmetry-based application examples can also utilize symmetry to perform uplink channel estimation while performing downlink channel estimation.

[0387] It should be noted that the above-described beam pair application examples are merely exemplary, and the channel estimation according to the embodiments of this disclosure can also be used in combination with various current and future beamforming techniques in various ways.

[0388] Second Application Example

[0389] The embodiments of this disclosure are also particularly suitable for applications of wireless communication systems where communication between the transmitter and receiver has a large number of direct paths. Because of the presence of a small number of obstacles, the channels can be sparsely arranged, and the embodiments of this disclosure can be applied based on this sparsity.

[0390] Besides the direct-path characteristic of millimeter-wave systems, traditional decimeter-wave / centimeter-wave systems are now seeing scenarios where aircraft communicate with ground base stations. In these cases, the communication path between the aircraft and the base station is mostly direct, with few obstacles obstructing the view. Furthermore, the method disclosed herein can also be used for direct channel estimation in aviation communication scenarios between base stations and aircraft, and between base stations and ordinary users / users in open environments such as rural areas (where there is less obstruction leading to sparse channel conditions).

[0391] According to some embodiments, the electronic device is implemented as an aircraft and further includes an altitude determination unit configured to determine the current flight altitude of the aircraft and provide it to the processing circuit. The processing circuit is configured to estimate the channel state on communication resources in the first frequency domain range and estimate the channel path condition from the transmitter to the receiver when it is determined that the flight altitude is higher than a predetermined threshold.

[0392] Figure 23 This is an example of an application instance where the downlink channel is determined via downlink CSI-RS transmission in an exemplary asymmetric scenario. Here, gNB indicates the base station, and UE indicates a drone or other similar high-altitude flying device.

[0393] First, the UE side notifies the base station side of the flight altitude information.

[0394] Drones can determine their altitude in various ways. Generally, it's measured using ultrasonic sensors (which measure distance to the ground, but are less common) or barometers (altitude affects atmospheric pressure). Horizontal coordinates are determined by the drone's GPS module. While a drone's GPS module can also provide altitude information, mainstream drones tend to use barometers because low-cost GPS devices have too low a data refresh rate; data lag during high-speed movement can cause the drone to lose altitude.

[0395] According to the embodiments, the base station can determine the operating mode of the UE by analyzing the flight altitude information sent by the UE. For example, when the flight altitude information is lower than a certain altitude threshold, the base station can consider the UE to be a normal UE. In this case, the method disclosed herein is not used, but a traditional method is used for channel estimation. On the other hand, when the flight altitude information is greater than or equal to the certain altitude threshold, the UE is considered to be a high-altitude flight device, such as a drone. Since the communication between them conforms to an unobstructed communication scenario, the embodiments of this disclosure can be applied for channel estimation, and so on.

[0396] It should be noted that transmitting this flight altitude information is optional. In other implementations, the UE can directly inform the base station that it is a drone through other means. In this case, the base station can directly use the embodiments of this disclosure to perform channel estimation, etc., without having to perform the determination as described above.

[0397] Then, the base station carries downlink reference signals on communication resources in the first frequency domain range of the communication system.

[0398] The physical resources where the reference signal is located can be flexibly configured in various ways. For example, they can be determined based on factors such as resource availability.

[0399] Communication resources within the first frequency domain can be utilized to transmit downlink reference signals from the base station to the user terminal. It should be noted that communication resources within the first frequency domain can be communicated to the user terminal in various ways. For example, they can be communicated via broadcast information, dedicated information, or other notification information. Furthermore, they can also be transmitted to the user terminal through a different channel than the downlink reference signal.

[0400] As another embodiment, the physical resources where the reference signal is located can also be pre-fixed through a protocol. In this case, the physical resources do not need to be notified to the user, because the user is already aware of this situation in advance.

[0401] The UE can receive downlink reference signals on communication resources within a first frequency domain range and estimate the channel state of the communication resources within that first frequency domain range. This estimation operation can be performed as described in the embodiments of this disclosure above.

[0402] The user side can determine downlink path parameters based on the estimated channel state of communication resources in the first frequency domain range. For example, as described in the embodiments of this disclosure above, the channel path conditions from the base station to the user side are estimated using the estimated channel state of communication resources in the first frequency domain range, thereby determining the downlink path parameters.

[0403] Then, the user side can notify the base station side of the downlink path parameters.

[0404] According to another embodiment, the downlink path parameters can be determined at the base station side. In this case, the user side can notify the base station side of the estimated channel state of the communication resources in the first frequency domain range, and the base station side can determine the downlink path parameters based on the estimated channel state of the communication resources in the first frequency domain range, for example, as described in the embodiments of this disclosure above, by using the estimated channel state of the communication resources in the first frequency domain range to estimate the channel path conditions from the base station to the user side, thereby determining the downlink path parameters.

[0405] The base station restores the downlink channel state of communication resources in other frequency domains of the communication system based on the determined downlink path parameters, as described in the embodiments of this disclosure above.

[0406] The base station can determine downlink resource scheduling, scheduling coding scheme, baseband precoding, MU-MIMO user pairing, and other multi-antenna processing for data transmission to the user equipment based on the downlink channel status of communication resources in various frequency domains of the communication system. It also provides downlink resource indications to the user side.

[0407] Therefore, the base station can transmit downlink data through downlink beam pairs.

[0408] In asymmetric scenarios, uplink path estimation and transmission between user equipment and base station can also be referenced as in the first application example. Figure 20 The execution is carried out in that way, except that the determination of the beam pair is omitted, which will not be explained in detail here.

[0409] It should be noted that communication between the aircraft user equipment and the base station may also exhibit channel symmetry. In this symmetrical scenario, uplink / downlink channel estimation and transmission between the user equipment and the base station can also be performed as described in the first embodiment. Figure 21 and 22 The procedure is performed as described, except that the determination of the beam pair is omitted, which will not be explained in detail here.

[0410] It should be noted that the second application example described above is mainly based on aircraft. However, it should be understood that the UE can also represent a regular user equipment in an open environment, and channel estimation / transmission can be performed similarly, except that the user equipment does not need to provide altitude information in this case.

[0411] Third Application Example

[0412] The embodiments of this disclosure can also be applied to the data demodulation process. The channel estimation method proposed in this disclosure can be used to demodulate data, in which case the reference signal used in the estimation process is the demodulation reference signal (DM-RS).

[0413] The following will combine Figures 24-25 This description illustrates the application of channel estimation techniques according to embodiments of the present disclosure during data demodulation using DMRS. In the accompanying drawings, gNB indicates a base station, and UE indicates a user equipment, such as a mobile phone. It should be noted that this is merely exemplary, and the transmitter and receiver can have various other implementations, as long as they communicate with each other.

[0414] Figure 24 This is an application example of DMRS downlink transmission.

[0415] First, the base station provides downlink resource indications to the user terminal. Downlink resource indications can be provided in various ways, such as DCI.

[0416] Downlink resources can be flexibly configured in various ways. For example, they can be determined based on factors such as resource availability. As another embodiment, the downlink source can also be pre-fixed via a protocol, in which case the physical resources do not need to be notified to the user, because the user is already aware of this situation.

[0417] Then, the base station carries DMRS on some subcarriers of the scheduled downlink data resource block, while carrying downlink data on other subcarriers. Downlink data signals can be carried and transmitted in various ways, such as by being carried and transmitted via PDSCH.

[0418] The user side can receive downlink data signals on designated downlink data resource blocks and estimate the channel state of some subcarriers. This estimation operation can be performed as described in the embodiments of this disclosure above, i.e., by analyzing the downlink data signal to obtain the DMRS as a reference signal, and then estimating the channel state of some subcarriers based on the obtained DMRS.

[0419] The user side can determine the downlink path parameters based on the estimated channel state of some subcarriers. For example, as described in the embodiments of this disclosure above, the channel path conditions from the base station to the user side are estimated using the estimated channel state of communication resources in the first frequency domain range, thereby determining the downlink path parameters.

[0420] Then, the user side can restore the downlink channel state of other subcarriers on the downlink data resource block based on the determined downlink path parameters, as described in the embodiments of this disclosure above.

[0421] Then, the user side can use the downlink channel state of all subcarriers on the downlink data resource block to demodulate the data on the downlink data resource block.

[0422] Further processing can be performed based on the data demodulation results. For example, a HARQ (Hybrid Automatic Repeat Request) process might be initiated based on the data demodulation results.

[0423] Figure 25 This is an application example of DMRS uplink transmission.

[0424] First, the base station provides the uplink resource indication to the user terminal. The uplink resource indication can be provided in various ways, such as as a DCI containing UL grants.

[0425] Uplink resources can be flexibly configured in various ways. For example, they can be determined based on factors such as resource availability. As another embodiment, the uplink source can also be pre-fixed via a protocol, in which case the physical resources do not need to be notified to the user, because the user is already aware of this situation.

[0426] Then, on the user side, DMRS is carried on some subcarriers of the scheduled uplink data resource block, while uplink data is carried on other subcarriers. Uplink data signals can be carried and transmitted in various ways, such as by being carried and transmitted via PUSCH.

[0427] The base station can receive uplink data signals on the allocated uplink data resource blocks and estimate the channel state of some subcarriers. This estimation operation can be performed as described in the embodiments of this disclosure above, i.e., by analyzing the uplink data signals to obtain the DMRS as a reference signal, and then estimating the channel state of some subcarriers based on the obtained DMRS.

[0428] The base station can determine uplink path parameters based on the estimated channel state of some subcarriers, for example, as described in the embodiments of this disclosure above, by using the estimated channel state of communication resources in a first frequency domain range to estimate the channel path conditions from the base station to the user side, thereby determining the uplink path parameters.

[0429] Then, the base station can restore the uplink channel state of other subcarriers on the uplink data resource block based on the determined uplink path parameters, as described in the embodiments of this disclosure above.

[0430] Then, the user side can use the uplink channel state of all subcarriers on the uplink data resource block to demodulate the data on the uplink data resource block.

[0431] Further processing can be performed based on the data demodulation results. For example, a HARQ (Hybrid Automatic Repeat Request) process might be initiated based on the data demodulation results.

[0432] It should be noted that the above application examples are merely exemplary. The embodiments of this disclosure can also be implemented in any other suitable manner within the above application examples, and the advantageous effects obtained by the embodiments of this disclosure can still be achieved. Furthermore, the embodiments of this disclosure can also be applied to other similar application examples, and the advantageous effects obtained by the embodiments of this disclosure can still be achieved.

[0433] It should be understood that the machine-executable instructions in a machine-readable storage medium or program product according to embodiments of this disclosure can be configured to perform operations corresponding to the above-described device and method embodiments. Embodiments of the machine-readable storage medium or program product will be clear to those skilled in the art when referring to the above-described device and method embodiments, and therefore will not be described again. Machine-readable storage media and program products used to carry or include the above-described machine-executable instructions also fall within the scope of this disclosure. Such storage media may include, but are not limited to, floppy disks, optical disks, magneto-optical disks, memory cards, memory sticks, etc.

[0434] Furthermore, it should be understood that the aforementioned series of processes and devices can also be implemented via software and / or firmware. In the case of implementation via software and / or firmware, data can be transferred from storage media or networks to computers with dedicated hardware architectures, such as… Figure 26 The general-purpose personal computer 1300 shown is equipped with the programs that constitute the software, and the computer is able to perform various functions when various programs are installed. Figure 26 This is a block diagram illustrating an example structure of a personal computer as an information processing device that may be employed in embodiments of this disclosure. In one example, the personal computer may correspond to the exemplary terminal device described above according to this disclosure.

[0435] existFigure 26 In this system, the central processing unit (CPU) 1301 performs various processes based on the program stored in the read-only memory (ROM) 1302 or the program loaded into the random access memory (RAM) 1303 from the storage section 1308. The RAM 1303 also stores, as needed, the data required when the CPU 1301 performs various processes.

[0436] CPU 1301, ROM 1302 and RAM 1303 are connected to each other via bus 1304. Input / output interface 1305 is also connected to bus 1304.

[0437] The following components are connected to the input / output interface 1305: input section 1306, including a keyboard, mouse, etc.; output section 1307, including a display, such as a cathode ray tube (CRT), liquid crystal display (LCD), etc., and speakers, etc.; storage section 1308, including a hard disk, etc.; and communication section 1309, including a network interface card, such as a LAN card, modem, etc. The communication section 1309 performs communication processing via a network, such as the Internet.

[0438] As needed, drive 1310 is also connected to input / output interface 1305. Removable media 1311, such as disks, optical disks, magneto-optical disks, semiconductor memories, etc., are installed on drive 1310 as needed, so that computer programs read from them can be installed into storage section 1308 as needed.

[0439] When the above series of processes are implemented by software, the program constituting the software is installed from a network such as the Internet or a storage medium such as removable media 1311.

[0440] Those skilled in the art will understand that such storage media are not limited to Figure 26 The illustrated removable medium 1311 stores a program and is distributed separately from the device to provide the program to the user. Examples of removable media 1311 include magnetic disks (including floppy disks (registered trademark)), optical disks (including optical disc read-only memory (CD-ROM) and digital versatile disks (DVD)), magneto-optical disks (including mini-disk (MD) (registered trademark)), and semiconductor memory. Alternatively, the storage medium may be ROM 1302, a hard disk included in storage section 1308, etc., containing programs and distributed to the user along with the device containing them.

[0441] The technology disclosed herein can be applied to a variety of products. For example, the base station mentioned in this disclosure can be implemented as any type of evolved Node B (gNB), such as macro gNB and small gNB. Small gNB can be a gNB that covers a cell smaller than a macro cell, such as pico gNB, micro gNB, and femtocell gNB. Alternatively, the base station can be implemented as any other type of base station, such as NodeB and Base Transceiver Station (BTS). The base station may include: a subject configured to control wireless communication (also called base station equipment); and one or more remote radio heads (RRHs) located in a different location from the subject. In addition, the various types of terminals described below can operate as base stations by temporarily or semi-persistently performing base station functions.

[0442] For example, the terminal devices mentioned in this disclosure, also referred to in some examples as user equipment, can be implemented as mobile terminals (such as smartphones, tablet PCs, laptop PCs, portable gaming terminals, portable / dongle-type mobile routers, and digital camera devices) or in-vehicle terminals (such as car navigation devices). User equipment can also be implemented as terminals performing machine-to-machine (M2M) communication (also known as machine-type communication (MTC) terminals). Furthermore, user equipment can be a wireless communication module (such as an integrated circuit module comprising a single chip) installed on each of the aforementioned terminals.

[0443] The following will refer to Figures 27 through 30 Examples are described based on this disclosure.

[0444] [Example of a base station]

[0445] It should be understood that the term "base station" as used in this disclosure has the full breadth of its usual meaning and includes at least a wireless communication station used as part of a wireless communication system or radio system to facilitate communication. Examples of base stations may include, but are not limited to, the following: a base station may be one or both of a base transceiver unit (BTS) and a base station controller (BSC) in a GSM system; one or both of a radio network controller (RNC) and a Node B in a WCDMA system; an eNB in ​​LTE and LTE-Advanced systems; or a corresponding network node in a future communication system (e.g., a gNB, eLTE eNB, etc., that may appear in a 5G communication system). Some functions of the base station in this disclosure may also be implemented as an entity that controls communication in D2D, M2M, and V2V communication scenarios, or as an entity that plays a role in spectrum coordination in cognitive radio communication scenarios.

[0446] First Example

[0447] Figure 27 This is a block diagram illustrating a first example of a schematic configuration of a gNB to which the technologies of this disclosure can be applied. The gNB 1400 includes a plurality of antennas 1410 and a base station device 1420. The base station device 1420 and each antenna 1410 can be connected to each other via RF cables. In one implementation, the gNB 1400 (or base station device 1420) herein may correspond to the aforementioned electronic devices 300A, 1300A, and / or 1500B.

[0448] Each of the antennas 1410 includes one or more antenna elements (such as multiple antenna elements included in a multiple-input multiple-output (MIMO) antenna) and is used by the base station equipment 1420 to transmit and receive wireless signals. Figure 27 As shown, the gNB 1400 may include multiple antennas 1410. For example, the multiple antennas 1410 may be compatible with multiple frequency bands used by the gNB 1400.

[0449] The base station equipment 1420 includes a controller 1421, a memory 1422, a network interface 1423, and a wireless communication interface 1425.

[0450] The controller 1421 can be, for example, a CPU or a DSP, and operates various higher-level functions of the base station equipment 1420. For example, the controller 1421 generates data packets based on data in signals processed by the wireless communication interface 1425, and transmits the generated packets via the network interface 1423. The controller 1421 can bundle data from multiple baseband processors to generate bundled packets and transmit the generated bundled packets. The controller 1421 may have logical functions that perform controls such as radio resource control, radio bearer control, mobility management, admission control, and scheduling. This control can be performed in conjunction with nearby gNBs or core network nodes. The memory 1422 includes RAM and ROM, and stores programs executed by the controller 1421 and various types of control data (such as terminal lists, transmission power data, and scheduling data).

[0451] Network interface 1423 is a communication interface for connecting base station equipment 1420 to core network 1424. Controller 1421 can communicate with core network nodes or other gNBs via network interface 1423. In this case, gNB 1400 and core network nodes or other gNBs can be connected to each other via logical interfaces (such as S1 and X2 interfaces). Network interface 1423 can also be a wired communication interface or a wireless communication interface for wireless backhaul. If network interface 1423 is a wireless communication interface, it can use a higher frequency band for wireless communication compared to the frequency band used by wireless communication interface 1425.

[0452] Wireless communication interface 1425 supports any cellular communication scheme (such as LTE and LTE-Advanced) and provides wireless connectivity to terminals located in the cell of gNB 1400 via antenna 1410. Wireless communication interface 1425 typically includes, for example, a baseband (BB) processor 1426 and RF circuitry 1427. BB processor 1426 can perform, for example, encoding / decoding, modulation / demodulation, and multiplexing / demultiplexing, and performs various types of signal processing at layers such as L1, Media Access Control (MAC), Radio Link Control (RLC), and Packet Data Convergence Protocol (PDCP). Instead of controller 1421, BB processor 1426 may have some or all of the above-described logical functions. BB processor 1426 may be a memory storing communication control programs, or a module including a processor and associated circuitry configured to execute programs. Update programs can change the functionality of BB processor 1426. The module may be a card or blade inserted into a slot in base station equipment 1420. Alternatively, the module may be a chip mounted on a card or blade. Meanwhile, the RF circuit 1427 may include, for example, a mixer, a filter, and an amplifier, and transmits and receives wireless signals via the antenna 1410. Although Figure 27 An example of an RF circuit 1427 connected to an antenna 1410 is shown, but this disclosure is not limited to the illustration, and an RF circuit 1427 can be connected to multiple antennas 1410 simultaneously.

[0453] like Figure 27 As shown, the wireless communication interface 1425 may include multiple BB processors 1426. For example, the multiple BB processors 1426 may be compatible with multiple frequency bands used by the gNB 1400. Figure 27 As shown, the wireless communication interface 1425 may include multiple RF circuits 1427. For example, the multiple RF circuits 1427 may be compatible with multiple antenna elements. Although Figure 27An example is shown in which the wireless communication interface 1425 includes multiple BB processors 1426 and multiple RF circuits 1427, but the wireless communication interface 1425 may also include a single BB processor 1426 or a single RF circuit 1427.

[0454] Second Example

[0455] Figure 28 This is a block diagram illustrating a second example of a schematic configuration of a gNB to which the technologies of this disclosure can be applied. The gNB 1530 includes multiple antennas 1540, a base station device 1550, and an RRH 1560. The RRH 1560 and each antenna 1540 can be connected to each other via RF cables. The base station device 1550 and the RRH 1560 can be connected to each other via high-speed lines such as fiber optic cables. In one implementation, the gNB 1530 (or base station device 1550) herein may correspond to the aforementioned electronic devices 300A, 1300A, and / or 1500B.

[0456] Each of the antennas 1540 includes one or more antenna elements (such as multiple antenna elements included in a MIMO antenna) and is used by the RRH 1560 to transmit and receive wireless signals. Figure 28 As shown, the gNB 1530 may include multiple antennas 1540. For example, the multiple antennas 1540 may be compatible with multiple frequency bands used by the gNB 1530.

[0457] Base station equipment 1550 includes a controller 1551, a memory 1552, a network interface 1553, a wireless communication interface 1555, and a connection interface 1557. The controller 1551, memory 1552, and network interface 1553 are related to a reference... Figure 27 The controller 1421, memory 1422 and network interface 1423 described are the same.

[0458] Wireless communication interface 1555 supports any cellular communication scheme (such as LTE and LTE-Advanced) and provides wireless communication to terminals located in the sector corresponding to RRH 1560 via RRH 1560 and antenna 1540. Wireless communication interface 1555 may typically include, for example, a BB processor 1556. In addition to the BB processor 1556 being connected to the RF circuitry 1564 of RRH 1560 via connection interface 1557, the BB processor 1556 is connected to the reference... Figure 27 The BB processor 1426 is described as identical. Figure 28 As shown, the wireless communication interface 1555 may include multiple BB processors 1556. For example, the multiple BB processors 1556 may be compatible with multiple frequency bands used by the gNB 1530. Although Figure 28An example is shown in which the wireless communication interface 1555 includes multiple BB processors 1556, but the wireless communication interface 1555 may also include a single BB processor 1556.

[0459] Connection interface 1557 is an interface for connecting base station device 1550 (wireless communication interface 1555) to RRH 1560. Connection interface 1557 may also be a communication module for communication in the aforementioned high-speed line connecting base station device 1550 (wireless communication interface 1555) to RRH 1560.

[0460] The RRH 1560 includes a connectivity interface 1561 and a wireless communication interface 1563.

[0461] Connection interface 1561 is an interface for connecting RRH 1560 (wireless communication interface 1563) to base station equipment 1550. Connection interface 1561 can also be a communication module for communication in the aforementioned high-speed line.

[0462] Wireless communication interface 1563 transmits and receives wireless signals via antenna 1540. Wireless communication interface 1563 typically includes, for example, RF circuitry 1564. RF circuitry 1564 may include, for example, a mixer, filter, and amplifier, and transmits and receives wireless signals via antenna 1540. Although Figure 28 An example of an RF circuit 1564 connected to an antenna 1540 is shown, but this disclosure is not limited to the illustration, and an RF circuit 1564 can be connected to multiple antennas 1540 simultaneously.

[0463] like Figure 28 As shown, the wireless communication interface 1563 may include multiple RF circuits 1564. For example, the multiple RF circuits 1564 may support multiple antenna elements. Although Figure 28 An example is shown in which the wireless communication interface 1563 includes multiple RF circuits 1564, but the wireless communication interface 1563 may also include a single RF circuit 1564.

[0464] [Example regarding user equipment]

[0465] First Example

[0466] Figure 29This is a block diagram illustrating an example of a schematic configuration of a smartphone 1600 to which the technologies of this disclosure can be applied. The smartphone 1600 includes a processor 1601, a memory 1602, a storage device 1603, an external connection interface 1604, a camera device 1606, a sensor 1607, a microphone 1608, an input device 1609, a display device 1610, a speaker 1611, a wireless communication interface 1612, one or more antenna switches 1615, one or more antennas 1616, a bus 1617, a battery 1618, and an auxiliary controller 1619. In one implementation, the smartphone 1600 (or processor 1601) herein may correspond to the terminal devices 300B and / or 1500A described above.

[0467] The processor 1601 may be, for example, a CPU or a system-on-a-chip (SoC), and controls the application layer and other functions of the smartphone 1600. The memory 1602 includes RAM and ROM, and stores data and programs executed by the processor 1601. The storage device 1603 may include storage media such as semiconductor memory and hard disks. The external connectivity interface 1604 is an interface for connecting external devices, such as memory cards and Universal Serial Bus (USB) devices, to the smartphone 1600.

[0468] The camera device 1606 includes an image sensor (such as a charge-coupled device (CCD) and complementary metal-oxide-semiconductor (CMOS)) and generates captured images. The sensor 1607 may include a set of sensors, such as a measurement sensor, a gyroscope sensor, a magnetometer sensor, and an accelerometer sensor. The microphone 1608 converts sound input to the smartphone 1600 into an audio signal. The input device 1609 includes, for example, a touch sensor, keypad, keyboard, buttons, or switches configured to detect touches on the screen of the display device 1610 and receive operations or information input from the user. The display device 1610 includes a screen (such as a liquid crystal display (LCD) and an organic light-emitting diode (OLED) display) and displays the output image of the smartphone 1600. The speaker 1611 converts the audio signal output from the smartphone 1600 into sound.

[0469] The wireless communication interface 1612 supports any cellular communication scheme (such as LTE and LTE-Advanced) and performs wireless communication. The wireless communication interface 1612 typically includes, for example, a BB processor 1613 and RF circuitry 1614. The BB processor 1613 can perform, for example, encoding / decoding, modulation / demodulation, and multiplexing / demultiplexing, and performs various types of signal processing for wireless communication. Meanwhile, the RF circuitry 1614 can include, for example, mixers, filters, and amplifiers, and transmits and receives wireless signals via antenna 1616. The wireless communication interface 1612 can be a single chip module on which the BB processor 1613 and RF circuitry 1614 are integrated. Figure 29 As shown, the wireless communication interface 1612 may include multiple BB processors 1613 and multiple RF circuits 1614. Although Figure 29 An example is shown in which the wireless communication interface 1612 includes multiple BB processors 1613 and multiple RF circuits 1614, but the wireless communication interface 1612 may also include a single BB processor 1613 or a single RF circuit 1614.

[0470] In addition to cellular communication schemes, wireless communication interface 1612 can support other types of wireless communication schemes, such as short-range wireless communication schemes, near-field communication schemes, and wireless local area network (LAN) schemes. In this case, wireless communication interface 1612 may include a BB processor 1613 and RF circuitry 1614 for each wireless communication scheme.

[0471] Each of the antenna switches 1615 switches the connection destination of the antenna 1616 among multiple circuits (e.g., circuits for different wireless communication schemes) included in the wireless communication interface 1612.

[0472] Each of the antennas 1616 includes one or more antenna elements (such as multiple antenna elements included in a MIMO antenna) and is used by the wireless communication interface 1612 to transmit and receive wireless signals. Figure 29 As shown, the smartphone 1600 may include multiple antennas 1616. Although Figure 29 An example is shown in which the smartphone 1600 includes multiple antennas 1616, but the smartphone 1600 may also include a single antenna 1616.

[0473] Furthermore, the smartphone 1600 may include an antenna 1616 for each wireless communication scheme. In this case, the antenna switch 1615 can be omitted from the configuration of the smartphone 1600.

[0474] Bus 1617 connects processor 1601, memory 1602, storage device 1603, external connection interface 1604, camera device 1606, sensor 1607, microphone 1608, input device 1609, display device 1610, speaker 1611, wireless communication interface 1612, and auxiliary controller 1619 to each other. Battery 1618 supplies power to... Figure 29 The various blocks of the smartphone 1600 shown are powered, and the feeders are partially shown as dashed lines in the figure. The auxiliary controller 1619 operates the minimum necessary functions of the smartphone 1600, for example, in sleep mode.

[0475] Second example

[0476] Figure 30 This is a block diagram illustrating an example of a schematic configuration of a car navigation device 1720 to which the technology of this disclosure can be applied. The car navigation device 1720 includes a processor 1721, a memory 1722, a Global Positioning System (GPS) module 1724, a sensor 1725, a data interface 1726, a content player 1727, a storage medium interface 1728, an input device 1729, a display device 1730, a speaker 1731, a wireless communication interface 1733, one or more antenna switches 1736, one or more antennas 1737, and a battery 1738. In one implementation, the car navigation device 1720 (or processor 1721) herein may correspond to the aforementioned terminal devices 300B and / or 1500A.

[0477] The processor 1721 can be, for example, a CPU or a SoC, and controls the navigation functions and other functions of the car navigation device 1720. The memory 1722 includes RAM and ROM, and stores data and programs executed by the processor 1721.

[0478] GPS module 1724 uses GPS signals received from GPS satellites to measure the location (such as latitude, longitude, and altitude) of car navigation device 1720. Sensor 1725 may include a set of sensors, such as a gyroscope sensor, a geomagnetic sensor, and an air pressure sensor. Data interface 1726 is connected to, for example, an in-vehicle network 1741 via a terminal not shown, and acquires data generated by the vehicle (such as vehicle speed data).

[0479] Content player 1727 reproduces content stored on storage media (such as CDs and DVDs), which is inserted into storage media interface 1728. Input device 1729 includes, for example, a touch sensor, button, or switch configured to detect touch on the screen of display device 1730, and receives operations or information input from the user. Display device 1730 includes a screen such as an LCD or OLED display and displays images or reproduced content for navigation functions. Speaker 1731 outputs sound for navigation functions or reproduced content.

[0480] The wireless communication interface 1733 supports any cellular communication scheme (such as LTE and LTE-Advanced) and performs wireless communication. The wireless communication interface 1733 typically includes, for example, a BB processor 1734 and RF circuitry 1735. The BB processor 1734 can perform, for example, encoding / decoding, modulation / demodulation, and multiplexing / demultiplexing, and performs various types of signal processing for wireless communication. Meanwhile, the RF circuitry 1735 can include, for example, a mixer, filters, and amplifiers, and transmits and receives wireless signals via antenna 1737. The wireless communication interface 1733 can also be a chip module on which the BB processor 1734 and RF circuitry 1735 are integrated. Figure 30 As shown, the wireless communication interface 1733 may include multiple BB processors 1734 and multiple RF circuits 1735. Although Figure 30 An example is shown in which the wireless communication interface 1733 includes multiple BB processors 1734 and multiple RF circuits 1735, but the wireless communication interface 1733 may also include a single BB processor 1734 or a single RF circuit 1735.

[0481] In addition to cellular communication schemes, the wireless communication interface 1733 can support other types of wireless communication schemes, such as short-range wireless communication schemes, near-field communication schemes, and wireless LAN schemes. In this case, for each wireless communication scheme, the wireless communication interface 1733 may include a BB processor 1734 and an RF circuit 1735.

[0482] Each of the antenna switches 1736 switches the connection destination of the antenna 1737 among multiple circuits (such as circuits for different wireless communication schemes) included in the wireless communication interface 1733.

[0483] Each of the antennas 1737 includes one or more antenna elements (such as multiple antenna elements included in a MIMO antenna) and is used by the wireless communication interface 1733 to transmit and receive wireless signals. Figure 30 As shown, the car navigation device 1720 may include multiple antennas 1737. Although Figure 30An example is shown in which the car navigation device 1720 includes multiple antennas 1737, but the car navigation device 1720 may also include a single antenna 1737.

[0484] Furthermore, the car navigation device 1720 may include an antenna 1737 for each wireless communication scheme. In this case, the antenna switch 1736 can be omitted from the configuration of the car navigation device 1720.

[0485] Battery 1738 via feeder to Figure 30 The various blocks of the car navigation device 1720 shown are powered, and the feeders are partially shown as dashed lines in the figure. Battery 1738 accumulates the power supplied from the vehicle.

[0486] The technology disclosed herein can also be implemented as an in-vehicle system (or vehicle) 1740 including one or more blocks of an automotive navigation device 1720, an in-vehicle network 1741, and a vehicle module 1742. The vehicle module 1742 generates vehicle data (such as vehicle speed, engine speed, and fault information) and outputs the generated data to the in-vehicle network 1741.

[0487] Exemplary embodiments of the present disclosure have been described above with reference to the accompanying drawings; however, the present disclosure is by no means limited to the examples described above. Various changes and modifications can be made by those skilled in the art within the scope of the appended claims, and it should be understood that such changes and modifications naturally fall within the technical scope of the present disclosure.

[0488] For example, the multiple functions included in one unit in the above embodiments can be implemented by separate devices. Alternatively, the multiple functions implemented by multiple units in the above embodiments can be implemented by separate devices respectively. In addition, one of the above functions can be implemented by multiple units. Needless to say, such a configuration is included within the scope of the present disclosure.

[0489] In this specification, the steps described in the flowchart include not only processes executed sequentially in the stated order, but also processes executed in parallel or individually, rather than necessarily sequentially. Furthermore, even within the steps of sequential processing, needless to say, the order can be appropriately altered.

[0490] While this disclosure and its advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of this disclosure as defined by the appended claims. Furthermore, the terms "comprising," "including," or any other variations thereof used in embodiments of this disclosure are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

Claims

1. An electronic device for a receiver in a wireless communication system, comprising: The processing circuit is configured as follows: The channel state on communication resources carrying the reference signal is estimated based on a reference signal from the transmitter, wherein the frequency domain resources of the communication system are divided into multiple orthogonal frequency domain ranges, and the reference signal is distributed in the communication resources of the lower frequency domain range of the communication system; and Using the channel state of the communication resources in the lower frequency domain that has been estimated, the channel path condition from the transmitter to the receiver is estimated; The channel state from the transmitter to the receiver in the higher frequency domain communication resources is derived from the estimated channel path conditions. Furthermore, the channel state of the subcarriers containing the reference signals is jointly estimated using reference signals distributed over at least one time slot. The distribution of the reference signal, which is distributed in at least one time slot, is such that: in the specific time slot, the reference signal is distributed across the entire transmission frequency band; and in the remaining time slots, excluding the specific time slot, the reference signal is distributed only within a portion of the frequency band. The number of paths and the phase and intensity parameters of each path are estimated using a reference signal in the specific time slot, and the intensity parameters of each path are updated using the previously estimated number of paths and the phase parameters of each path in the time slot immediately following the specific time slot.

2. The electronic device as claimed in claim 1, wherein, The reference signal is distributed at predetermined intervals in the communication resources of the lower frequency domain.

3. The electronic device as claimed in claim 2, wherein, The predetermined interval is determined based on the maximum delay spread of the channel and the frequency domain spacing of adjacent communication resources in the communication system.

4. The electronic device as claimed in any one of claims 1-3, wherein, The upper limit of the predetermined interval between adjacent subcarriers in a subcarrier carrying a reference signal is determined by the maximum time delay spread of the channel and the system frequency spacing of the subcarriers.

5. The electronic device as claimed in any one of claims 1-3, wherein, The number of subcarriers containing the reference signal is determined based on the accuracy of channel estimation and the total bandwidth of communication resources in the lower frequency range expected to be occupied by the subcarriers containing the reference signal.

6. The electronic device as claimed in any one of claims 1-3, wherein, The channel path condition includes at least one of the following: the number of paths, the phase parameter of each path, and the intensity parameter of each path.

7. The electronic device as claimed in claim 6, wherein, The number of paths and the phase parameters of each path are estimated based on the spectrum of channel state data of the estimated lower frequency range of communication resources.

8. The electronic device of claim 7, wherein the number of paths corresponds to the number of peaks in the spectrum of the data that are above a predetermined threshold, and the phase parameter of each path is determined based on the spectrum of the peak corresponding to the path.

9. The electronic device of claim 7 or 8, wherein the intensity parameter of each path is estimated based on the channel state of the estimated lower frequency domain communication resources, the number of paths, and the phase parameter of each path.

10. The electronic device of claim 9, wherein the intensity parameter of each path is estimated by solving a system of linear equations relating the channel state of the estimated subcarriers, the number of paths, the phase parameter of each path, and the intensity parameter of each path established according to a multipath channel model.

11. A method for a receiver in a wireless communication system, comprising: The channel state on communication resources carrying the reference signal is estimated based on a reference signal from the transmitter, wherein the frequency domain resources of the communication system are divided into multiple orthogonal frequency domain ranges, and the reference signal is distributed in the communication resources of the lower frequency domain range of the communication system; and Using the channel state of the communication resources in the lower frequency domain that has been estimated, the channel path condition from the transmitter to the receiver is estimated; The channel state from the transmitter to the receiver on high-frequency communication resources is derived from the estimated channel path conditions. Furthermore, the channel state of the subcarriers containing the reference signals is jointly estimated using reference signals distributed over at least one time slot. The distribution of the reference signal, which is distributed in at least one time slot, is such that: in the specific time slot, the reference signal is distributed across the entire transmission frequency band; and in the remaining time slots, excluding the specific time slot, the reference signal is distributed only within a portion of the frequency band. The number of paths and the phase and intensity parameters of each path are estimated using a reference signal in the specific time slot, and the intensity parameters of each path are updated using the previously estimated number of paths and the phase parameters of each path in the time slot immediately following the specific time slot.

12. A non-transitory computer storage medium storing instructions that, when executed, cause a device to perform the method according to claim 11.

13. An apparatus for a wireless communication system, comprising: processor, and A non-transitory computer storage medium storing instructions that, when executed, cause a processor to perform the method according to claim 11.

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