Communication method and device and computer readable storage medium

Abstract

The invention provides a communication method and device and a computer readable storage medium, and the method comprises the steps: obtaining a first symbol sent to a high-speed user and a second symbol sent to at least one low-speed user, the high-speed user being a user whose moving speed exceeds a first threshold, and the second symbol being a user whose moving speed exceeds a second threshold; the at least one low-speed user is a user whose moving speed is lower than a first threshold; placing the first symbol in a plurality of resource blocks of a delay Doppler domain; converting the first symbols located in the time delay Doppler domain into third symbols located in the time-frequency domain, wherein the third symbols are distributed at different frequency domain positions of the time-frequency domain; placing the second symbol in a plurality of resource blocks in a time-frequency domain to obtain a total sending symbol in the time-frequency domain, the frequency domain position of the second symbol and the frequency domain position of the third symbol being mutually staggered; and sending the total sending symbol. The invention provides a scheme capable of enabling network equipment to serve high-speed users and low-speed users at the same time.

Description

Technical Field

[0001] This application relates to the field of communication technologies, and in particular, to a communication method, an apparatus, and a computer-readable storage medium. Background Art

[0002] With the continuous development of high-mobility terminals such as unmanned aerial vehicles, autonomous driving, high-speed trains, and low-earth orbit satellites, higher requirements are put forward for aspects such as data transmission rate and transmission delay. However, communication of high-mobility terminal devices often causes severe Doppler frequency shift, which will cause serious interference to the Orthogonal Frequency-Division Multiplexing (OFDM) waveform, resulting in a serious decline in system performance. To meet the requirements of reliable communication for future high-mobility terminals, the Orthogonal Time Frequency Space (OTFS) technology introduces the delay-Doppler domain. In high-speed mobile scenarios, compared with OFDM, the OTFS system exhibits more excellent performance, including characteristics such as higher spectral efficiency.

[0003] In the OTFS system, channel estimation aims to solve the challenges of dynamic changes in spectrum and delay in high-mobility scenarios to obtain accurate channel state information. In the delay-Doppler domain, the traditional channel estimation method is that each user sends a single high-power pulse. After resource mapping in the delay-Doppler domain, the pilot and data symbols are converted to the time-frequency domain together, and then converted to the time domain to send the signal. The receiving end estimates the OTFS channel response by setting a reasonable threshold.

[0004] However, in the prior art, when the resource blocks in the entire delay-Doppler domain are occupied by high-speed user symbols, the network device cannot serve low-speed users simultaneously. Summary of the Invention

[0005] This application provides a solution that enables a network device to serve high-speed users and low-speed users simultaneously.

[0006] To achieve the above object, this application provides the following technical solutions:

[0007] In a first aspect, a communication method is provided. The communication method includes: obtaining a first symbol sent to a high-speed user and a second symbol sent to at least one low-speed user, where the high-speed user is a user with a moving speed exceeding a first threshold, and the at least one low-speed user is a user with a moving speed lower than the first threshold; placing the first symbol in a plurality of resource blocks in the time-delay Doppler domain; converting the first symbol located in the time-delay Doppler domain into a third symbol located in the time-frequency domain, and the third symbol is distributed at different frequency domain positions in the time-frequency domain; placing the second symbol in the plurality of resource blocks in the time-frequency domain to obtain a total transmission symbol located in the time-frequency domain, and the frequency domain position where the second symbol is located is interleaved with the frequency domain position where the third symbol is located; and transmitting the total transmission symbol.

[0008] Optionally, a first pilot symbol in the third symbol is located at the same one or more time domain positions, and a second pilot symbol in the second symbol is located at the one or more time domain positions.

[0009] Optionally, the placing the first symbol in a plurality of resource blocks in the time-delay Doppler domain includes: dividing M×N first resource blocks in the time-delay Doppler domain into p×q second resource blocks, where M, N, p, and q are all positive integers, and M is divisible by p, and N is divisible by q; placing the first symbol in a target second resource block, where the first symbol includes a data symbol, a pilot symbol, and a guard interval symbol; and repeatedly placing the target second resource block in the first resource block after rotating it according to a target rotation factor.

[0010] Optionally, the repeatedly placing the target second resource block in the first resource block after rotating it according to a target rotation factor includes: repeatedly placing the rotated target second resource block p times in the time-delay dimension and q times in the Doppler dimension in the first resource block.

[0011] Optionally, the following formula is used to rotate the target second resource block:

[0012]

[0013] where represents the rotated target first resource block, l = 0, …, M - 1, k = 0, …, N - 1, represents the target second resource block, l′ = 0, …, M / p - 1, k′ = 0, …, N / q - 1, c = 0, …, p - 1, d = 0, …, q - 1, index = 1, (·) p represents the modulo operation with respect to p, represents the floor operation.

[0014] Optionally, the time interval between adjacent second pilot symbols in the second symbol is inversely proportional to the Doppler frequency of the channel.

[0015] In a second aspect, the present application also discloses a channel estimation method, which includes: receiving total received symbols, where the total received symbols are obtained after the total transmitted symbols are transmitted through a wireless channel; and respectively performing channel estimation on the channels of the high-speed user and the at least one low-speed user according to the total received symbols.

[0016] Optionally, the respectively performing channel estimation on the channels of the high-speed user and the low-speed user according to the total received symbols includes: detecting the first symbol by using the second symbol as noise in the time-delay Doppler domain, and performing channel estimation on the high-speed user according to the detected first symbol; deleting the detected first symbol in the time-delay Doppler domain, and converting the remaining second symbols to the time-frequency domain to perform channel estimation on the at least one low-speed user.

[0017] In a third aspect, the present application also discloses a communication device, which includes: an acquisition module, configured to acquire a first symbol sent to a high-speed user and a second symbol sent to at least one low-speed user, where the high-speed user is a user with a moving speed exceeding a first threshold, and the at least one low-speed user is a user with a moving speed lower than the first threshold; a first placement module, configured to place the first symbol in a plurality of resource blocks in the time-delay Doppler domain; a conversion module, configured to convert the first symbol located in the time-delay Doppler domain into a third symbol located in the time-frequency domain, and the third symbol is distributed at different frequency domain positions in the time-frequency domain; a second placement module, configured to place the second symbol in a plurality of resource blocks in the time-frequency domain to obtain a total transmitted symbol located in the time-frequency domain, and the frequency domain position where the second symbol is located is interleaved with the frequency domain position where the third symbol is located; and a transmission module, configured to transmit the total transmitted symbol.

[0018] In a fourth aspect, the present application also discloses a channel estimation device, which includes: a receiving module, configured to receive total received symbols, where the total received symbols are obtained after the total transmitted symbols are transmitted through a wireless channel; and a channel estimation module, configured to respectively perform channel estimation on the channels of the high-speed user and the at least one low-speed user according to the total received symbols.

[0019] In a fifth aspect, a computer-readable storage medium is provided, on which a computer program is stored, and the computer program is run by a processor to execute any method provided in the first aspect or the second aspect.

[0020] In a sixth aspect, a communication device is provided, including a memory and a processor. A computer program that can run on the processor is stored on the memory, and the processor runs the computer program to execute any one of the methods provided in the first aspect.

[0021] In a seventh aspect, a communication device is provided, including a memory and a processor. A computer program that can run on the processor is stored on the memory, and the processor runs the computer program to execute any one of the methods provided in the second aspect.

[0022] In an eighth aspect, a computer program product is provided, on which a computer program is stored. The computer program is run by a processor to execute any one of the methods provided in the first aspect or the second aspect.

[0023] In a ninth aspect, an embodiment of the present application further provides a chip (or a data transmission device). A computer program is stored on the chip, and when the computer program is executed by the chip, the steps of the above method are implemented.

[0024] In a tenth aspect, an embodiment of the present application further provides a system chip, which is applied to a terminal. The chip system includes at least one processor and an interface circuit. The interface circuit and the at least one processor are interconnected by a line. The at least one processor is configured to execute instructions to execute any one of the methods provided in the first aspect or the second aspect.

[0025] Compared with the prior art, the technical solution of the present application has the following beneficial effects:

[0026] In the technical solution of the present application, the first symbol sent to a high-speed user is placed in multiple resource blocks in the time-delay Doppler domain; the first symbol located in the time-delay Doppler domain is converted into a third symbol located in the time-frequency domain, and the third symbol is distributed at different frequency domain positions in the time-frequency domain; the second symbol is placed in multiple resource blocks in the time-frequency domain to obtain the total transmission symbol located in the time-frequency domain. The frequency domain position where the second symbol is located is staggered with the frequency domain position where the third symbol is located; the total transmission symbol is sent. The technical solution of the present application combines the channel characteristics experienced by the signal sent to the high-speed user and the signal sent to the low-speed user. The first symbol (i.e., data and pilot) sent to the high-speed user is placed in the time-delay Doppler domain and OTFS transmission is adopted; the data and pilot sent to the low-speed user are placed in the time-frequency domain and OFDM transmission is adopted. By designing the symbol placement scheme for high-speed users, the high-speed user symbols can be concentrated at certain frequency points after being transformed into the time-frequency domain, and the symbols of low-speed users are placed at the remaining subcarrier frequencies, so as to achieve data orthogonality between users in the time-frequency domain and meet the requirement that the network device serves high-speed users and low-speed users simultaneously. In addition, the pilot structure in the time-frequency domain in the technical solution of the present application is simple, and the solution is simple and easy to implement.

[0027] Further, in the technical solution of the present application, M×N first resource blocks in the time-delay Doppler domain are divided into M / p×N / q second resource blocks, where M, N, p, and q are all positive integers, and M is divisible by p, and N is divisible by q; the first symbol is placed in the target second resource block, and the first symbol includes a data symbol, a pilot symbol, and a guard interval symbol; the target second resource block is repeatedly placed in the first resource block after being rotated according to the target rotation factor. The technical solution of the present application realizes that the high-speed user data and pilots are interference-free in the time-delay Doppler domain, and after converting them to the time-frequency domain, the symbols between users can still be orthogonal. Moreover, when the total transmitted symbols in the time-frequency domain are converted to the time domain using an ideal waveform and passed through a wireless channel, and then the received symbols are converted back to the time-frequency domain, the symbols of high-speed users do not interfere with each other, improving the communication quality. Description of the Drawings

[0028] Figure 1 is a schematic diagram of the modulation and demodulation process of an OTFS system in the prior art;

[0029] Figure 2 is a flowchart of a communication method provided by an embodiment of the present application;

[0030] Figure 3 is a schematic diagram of the distribution of the first symbol in the time-delay Doppler domain provided by an embodiment of the present application;

[0031] Figure 4 is a schematic diagram of the distribution of the second symbol in the time-frequency domain provided by an embodiment of the present application;

[0032] Figure 5 is a schematic diagram of the distribution of the total transmitted signal in the time-frequency domain provided by an embodiment of the present application;

[0033] Figure 6 is a schematic diagram of the change curve of the bit error rate and the signal-to-noise ratio provided by an embodiment of the present application;

[0034] Figure 7 is another schematic diagram of the change curve of the bit error rate and the signal-to-noise ratio provided by an embodiment of the present application;

[0035] Figure 8 is a schematic diagram of the structure of a communication device provided by an embodiment of the present application;

[0036] Figure 9 is a schematic diagram of the hardware structure of a communication device provided by an embodiment of the present application. Detailed Embodiments

[0037] The communication system applicable to the embodiments of the present application includes, but is not limited to, Long Term Evolution (LTE) systems, 5th-generation (5G) systems, New Radio (NR) systems, as well as future evolved systems or multi-communication convergence systems. Among them, the 5G system can be a Non-StandAlone (NSA) 5G system or a StandAlone (SA) 5G system. The technical solution of the present application is also applicable to different network architectures, including but not limited to relay network architectures, dual-connection architectures, Vehicle-to-Everything architectures, etc.

[0038] This application mainly relates to the communication between terminal devices and network devices. Among them:

[0039] The network device in the embodiments of the present application can also be referred to as an access network device. For example, it can be a base station (BaseStation, BS) (also referred to as base station equipment). A network device is a device deployed in a Radio Access Network (RAN) to provide wireless communication functions. For example, the device providing base station functions in the 2nd-Generation (2G) network includes a Base Transceiver Station (BTS), the device providing base station functions in the 3rd-Generation (3G) network includes a NodeB, the device providing base station functions in the 4th-Generation (4G) network includes an evolved NodeB (eNB), in a Wireless Local Area Networks (WLAN), the device providing base station functions is an Access Point (AP), the device providing base station functions in NR is a next generation NodeBase station (gNB), and a next-generation evolved NodeB (ng-eNB). Among them, the communication between the gNB and the terminal device uses NR technology, and the communication between the ng-eNB and the terminal device uses Evolved Universal Terrestrial Radio Access (E-UTRA) technology. Both the gNB and the ng-eNB can be connected to the 5G core network. The network device in the embodiments of the present application also includes devices providing base station functions in future new communication systems, etc.

[0040] The terminal equipment in the embodiments of the present application may refer to various forms of access terminals, user units, user stations, mobile stations, mobile stations (Mobile Station, MS), remote stations, remote terminals, mobile devices, user terminals, wireless communication devices, user agents or user devices. The terminal equipment may also be a cellular phone, cordless phone, Session Initiation Protocol (SIP) phone, Wireless Local Loop (WLL) station, Personal Digital Assistant (PDA), handheld device with wireless communication function, computing device or other processing device connected to a wireless modem, vehicle-mounted device, wearable device, terminal equipment in the future 5G network or terminal equipment in the future evolved Public Land Mobile Network (PLMN), etc. The embodiments of the present application are not limited thereto. The terminal equipment may also be referred to as User Equipment (UE), terminal, etc.

[0041] As described in the background art, in the prior art, when the resource blocks in the entire time-delay Doppler domain are occupied by high-speed user symbols, the network device cannot serve low-speed users simultaneously.

[0042] The technical solution of the present application combines the channel characteristics experienced by the signals sent to high-speed users and the signals sent to low-speed users, places the first symbol (i.e., data and pilot) sent to high-speed users in the time-delay Doppler domain and uses OTFS transmission; places the data and pilot sent to low-speed users in the time-frequency domain and uses OFDM transmission. By designing the symbol placement scheme for high-speed users, the high-speed user symbols can be concentrated at certain frequency points after being transformed into the time-frequency domain, and the symbols of low-speed users are placed at the remaining subcarrier frequencies, thereby realizing data orthogonality between users in the time-frequency domain and meeting the requirement that the network device serves high-speed users and low-speed users simultaneously. In addition, the time-frequency domain pilot structure in the technical solution of the present application is simple and the scheme is easy to implement.

[0043] In the embodiments of the present application, regarding OTFS and symbols: by sampling the time axis and frequency axis at intervals of T (seconds) and Δf (Hz) respectively, the time-frequency signal plane is discretized into an M×N grid (for some integers M, N>0), and the time-frequency signal plane is as shown in formula (1),

[0044] Λ = {(mΔf, nT), m = 0,..., M - 1, n = 0,..., N - 1} (1)

[0045] The modulated time-frequency domain samples X[m,n], where m = 0, ..., M-1 and n = 0, ..., N-1, are transmitted through an OTFS frame with a duration T f = NT, and the bandwidth B = MΔf. The delay-Doppler plane is discretized into an M×N information grid, and the delay-Doppler plane is shown in Equation (2):

[0046]

[0047] where 1 / MΔf and 1 / NT represent the quantization steps of the delay axis and the Doppler axis, respectively.

[0048] In the embodiments of this application, regarding OTFS modulation and demodulation, reference can be made to Figure 1 the shown process.

[0049] The modulator first maps a set of NM information symbols {x[l,k], l = 0, ..., M-1, k = 0, …, N-1} from a modulation alphabet of size Q, such as Quadrature Amplitude Modulation (QAM) symbols, arranges them on the delay-Doppler information grid Γ, and obtains the transmitted signal X [l,k] in the delay-Doppler domain. The symbols X DD [l,k] in the time-frequency domain grid are obtained using the Inverse Symplectic Finite Fourier Transform (ISFFT). Next, the transmitted signal X TF [m,n] is subjected to a Heisenberg transform using the transmit pulse g tx (t) to obtain the time-domain signal s(t). TF [m,n] is subjected to a Heisenberg transform using the transmit pulse g

[0050] The time-domain signal s(t) is transmitted through a wireless channel with a baseband channel impulse response h(τ,v), where h(τ,ν) characterizes the channel response to a pulse with a delay τ and a Doppler shift ν. The demodulator performs a Wigner transform on the received signal r(t) (implementing a receive filter with the pulse response g rx (t)). Then sampling is performed to obtain the signal Y TF [m,n] in the time-frequency domain. Then, a Symplectic Finite Fourier Transform (SFFT) is performed on Y TF [m,n] to obtain the symbols Y DD [m,n] in the delay-Doppler domain for symbol detection.

[0051] To make the above objects, features, and advantages of the present application more apparent and understandable, the following provides a detailed description of specific embodiments of the present application with reference to the accompanying drawings.

[0052] See Figure 2 , the method provided by the present application specifically includes the following steps:

[0053] Step 201: Obtain a first symbol sent to a high-speed user and a second symbol sent to at least one low-speed user; wherein, the high-speed user is a user with a moving speed exceeding a first threshold, and the at least one low-speed user is a user with a moving speed lower than the first threshold;

[0054] Step 202: Place the first symbol in multiple resource blocks in the time-delay Doppler domain;

[0055] Step 203: Convert the first symbol in the time-delay Doppler domain into a third symbol in the time-frequency domain, and the third symbol is distributed at different frequency domain positions in the time-frequency domain;

[0056] Step 204: Place the second symbol in multiple resource blocks in the time-frequency domain to obtain the total transmission symbol in the time-frequency domain, and the frequency domain position where the second symbol is located is interleaved with the frequency domain position where the third symbol is located;

[0057] Step 205: Transmit the total transmission symbol.

[0058] It should be noted that the sequence numbers of the steps in this embodiment do not represent the limitation of the execution order of each step.

[0059] It can be understood that in specific implementations, the communication method can be implemented in the form of a software program, and this software program runs in a processor integrated inside a chip or a chip module. This method can also be implemented in a way that combines software and hardware, and the present application does not make any restrictions.

[0060] The communication method of the embodiment of the present application can be used in a network device, and specifically, each step of the above method can be executed by a modulator of the network device. Correspondingly, each step of the channel estimation method can be executed by a demodulator of the terminal device.

[0061] In this embodiment, the channel experienced by the second symbol sent to the low-speed user has no Doppler frequency shift, and the second symbol can be directly placed in the resource blocks in the time-frequency domain without going through the conversion in the time-delay Doppler domain. The first symbol sent to the high-speed user can be placed in the resource blocks in the time-delay Doppler domain.

[0062] It should be noted that the specific value of the first threshold can be set according to the actual application scenario, and the present application does not make any restrictions on this.

[0063] In the embodiments of the present application, it is considered that a network device serves 1 high-speed user and M / 2 low-speed users, where M is a positive integer greater than or equal to 2. Let u = 0 be the high-speed user, and u = 1,..., M / 2 be the low-speed users. The first symbols sent to the high-speed user are placed in M×N resource blocks in the time-delay Doppler domain, and the second symbols sent to the low-speed users are placed in M×N resource blocks in the time-frequency domain.

[0064] Specifically, the M×N first symbols in the time-delay Doppler domain sent to the high-speed user are l ∈ {0,..., M - 1}, k ∈ {0,..., N - 1}.

[0065] Furthermore, the M×N-dimensional first resource blocks in the time-delay Doppler domain are divided into pq -dimensional second resource blocks. Among them, M / p ≥ 2l max +1, and N / q ≥ 2k max +1, where l max and k max respectively represent the maximum time-delay index and the maximum Doppler index. The symbols on the -dimensional second resource blocks are expressed as

[0066] Taking M = 8, N = 8, p = 2, and q = 1 as an example, please refer to Figure 3 Figure a in it, which shows the distribution of the first symbols in the second resource blocks. Specifically, the first pilot symbols, data symbols, and guard intervals in the first symbols are respectively arranged in the -dimensional target second resource blocks in the time-delay Doppler domain. The target second resource blocks are selected from p×q second resource blocks. Specifically, the positions occupied by the first pilot symbols, guard intervals, and data symbols are arranged in the target second resource blocks respectively.

[0067] More specifically, the first pilot symbol x Pilot in the first symbols is placed at the position [l′ Pilot , k′ Pilot of the target second resource block, and this position satisfies 0 ≤ l′ Pilot -l max ≤ l′ Pilot ≤ l′ Pilot +l max ≤ M - 1, 0 ≤ k′ Pilot -2k max ≤ k′ Pilot ≤ k′ Pilot +2k max ≤ N - 1. A guard interval is set between the first pilot symbol and the data symbol to reduce the interference between the two. The first symbols in the target second resource block can be expressed as:

[0068]

[0069] Furthermore, the target second resource block with the target rotation factor is rotated and then repeatedly placed in the first resource block. The distribution of the first symbol in the M×N-dimensional first resource block is as shown in Figure 3 Figure b in the figure. That is to say, the rotated target second resource block is repeatedly placed p times in the time delay dimension and q times in the Doppler dimension in the first resource block.

[0070] Specifically, after multiplying by the corresponding rotation factor according to formula (4), it is arranged p times along the time delay dimension and q times along the Doppler dimension to obtain the first symbol in the M×N-dimensional first resource block, that is:

[0071]

[0072] where l = 0, …, M−1, k = 0, …, N−1, l′ = 0, …, M / p−1, k′ = 0, …, N / q−1, c = 0, …, p−1, d = 0, …, q−1, index = 0, …, pq−1, (·) p represents taking the modulus with respect to p represents the floor operation.

[0073] In a specific implementation manner of step 203, the first symbol in the time delay-Doppler domain is converted to the time-frequency domain by using the ISFFT to obtain the third symbol as shown in formula (5):

[0074]

[0075] where m ∈ {0, …, M−1}, n ∈ {0, …, N−1}.

[0076] In a specific implementation manner of step 204, since there is no Doppler frequency shift in the channel experienced by the low-speed user's transmitted signal, the second symbol sent by the network device to the low-speed user can be directly placed in the time-frequency domain and jointly form the total transmitted signal with the third symbol converted to the time-frequency domain by the high-speed user. Among them, the second symbol and the third symbol are orthogonally placed on the time-frequency domain plane.

[0077] Specifically, M / 2 low-speed users share (M / 2)×N time-frequency domain resource blocks in an orthogonal manner. The nth (n = 0, …, N−1) symbol x u (n) sent by the network device to the u-th (u = 1, …, M / 2) low-speed user is placed on the [2(u−1), n]th resource block in the time-frequency domain, and the mapping scheme is:

[0078]

[0079] The second pilot symbol in the second symbol is placed in the time - frequency domain according to the OFDM block pilot design scheme, as Figure 4 shown. Among them, the second pilot symbol and the data symbol are respectively the two parts of × and □, and different shading represents the resource blocks occupied by different low - speed users. The second pilot symbols of different low - speed users are located at the same one or more time - domain positions, as Figure 4 shown in. The second pilot symbols of M / 2 low - speed users are all located on two time - domain symbols.

[0080] Furthermore, in order to track the characteristics of the time - varying channel, the frequency at which the second pilot signal is placed must be consistent with the coherence time. Since the coherence time of the channel is inversely proportional to the Doppler frequency f Doppler , the time interval S t between adjacent second pilot symbols is inversely proportional to the Doppler frequency f Doppler . Specifically, as shown in formula (7):

[0081]

[0082] Furthermore, the network device obtains the total transmission signal X on each time - frequency domain resource block according to the third symbol of the high - speed user and the second symbol TF of the low - speed user in the time - frequency domain:

[0083]

[0084] Specifically, please refer to Figure 5 . In the time - frequency domain, the third symbol is only concentrated in the resource blocks of some frequency sub - carriers, that is, Figure 5 some rows in the time - frequency domain grid. The positions with diagonal shading represent the resource blocks occupied by the third symbol, and other shading represents the resource blocks occupied by the second symbols of M / 2 low - speed users. The third symbol is only arranged in the even rows in the time - frequency domain plane, and the second symbol is arranged in the odd rows in the time - frequency domain plane. Through the above arrangement method, it can be ensured that the position of the block pilot sent to the low - speed user is not affected by the high - speed user data.

[0085] Specifically, the channel response of the u (u = 0, …, M / 2) - th user in the delay - Doppler domain is h u (τ, ν), where τ is the delay and ν is the Doppler shift. Since the delay - Doppler domain equivalent channel has a sparse characteristic and there are a small number of propagation paths between the transmitter and the receiver, the channel response h u (τ, ν) in the delay - Doppler domain can be expressed as:

[0086]

[0087] Among them, P u is the number of propagation paths, h u,i , τ u,i and ν u,i are the channel gain, time delay, and Doppler frequency shift corresponding to the i-th (1 ≤ i ≤ P u ) propagation path of the u-th user, respectively. are independent and identically distributed random variables, The time delay and Doppler frequency shift of the i-th propagation path are:

[0088]

[0089] Each OTFS frame has M × N symbols. To effectively suppress the interference caused by fractional time delay and fractional Doppler frequency shift, M and N need to be large enough, and T ≥ max{τ u,i , 1 ≤ i ≤ P u , 0 ≤ u ≤ U}, Δf ≥ max{ν u,i , 1 ≤ i ≤ P u , 0 ≤ u ≤ U}.

[0090] Assume that the transmit pulse g tx (t) and the receive pulse g rx (t) satisfy the biorthogonal condition. The input-output relationship of the u-th user in the time-frequency domain is:

[0091]

[0092] Among them, is the additive white Gaussian noise (AWGN) in the time-frequency domain.

[0093] The above embodiments illustrate the modulation process during the transmission of pilots and data at the transmitter. Then, for the receiver, it can perform channel estimation on the channels of low-speed users or high-speed users according to its own services. For example, if the terminal device itself is in a high-speed moving state and it is a high-speed user, it estimates the channel of the high-speed user based on the received signal; correspondingly, if the terminal device itself is in a stationary state or a low-speed moving state and it is a low-speed user, it estimates the channel of the low-speed user based on the received signal.

[0094] At the receiver, applying the SFFT to the total received signal obtains the received signal of the high-speed user in the time-delay Doppler domain:

[0095]

[0096] Among them, The symbol sent to the u-th user The symbol after SFFT conversion to the delay-Doppler domain, and the channel h w,0 (τ, ν) is:

[0097] h w,0 (τ, ν) = ∫ τ′ ∫ ν′ h u (τ′, ν′) w(τ - τ′, ν - ν′) e -j2πτv dτ′dν′ (13)

[0098] where

[0099] In this embodiment, the receiving end estimates the channel according to the received signal First, the channel of high-speed users is estimated, and then the channel of low-speed users is estimated. Among them, when the high-speed user detects its target symbol (i.e., the first symbol), the target symbol of the low-speed user (i.e., the second symbol) is regarded as noise. When detecting the low-speed user signal, the successive interference cancellation (SIC) technology is adopted. After demodulating the target symbol of the high-speed user in the delay-Doppler domain, the target symbol of the high-speed user is deleted, and then the target symbols of the remaining low-speed users are converted to the time-frequency domain for channel estimation and data detection.

[0100] It should be noted that the network device can also serve a larger number of high-speed users, and the first symbols of multiple high-speed users occupy multiple resource blocks in the delay-Doppler domain. The network device can also serve more than M / 2 low-speed users, and the resources of more than M / 2 low-speed users will overlap in the time-frequency domain. This application does not limit this.

[0101] For more specific implementation manners of the embodiments of this application, please refer to the foregoing embodiments, and details are not described herein again.

[0102] The following gives the system link simulation results of this new orthogonal multiple access pilot access scheme based on the OTFS system, so as to verify the advantages and feasibility of the present invention. Table 1 shows the basic parameter configurations of the simulation.

[0103] Table 1

[0104] (M,N) (48,32) Modulation method QPSK Carrier frequency 4 GHz Subcarrier spacing 1.5 kHz Pilot power 32 dB Detection method MMSE

[0105] Figure 6 and Figure 7When (M, N) = (48, 32), the modulation method is Quadrature Phase Shift Keying (QPSK), and the pilot signal-to-noise ratio in the time-delay Doppler domain is 32 dB, the curve of the Bit Error Rate (BER) of the OTFS link changing with the signal-to-noise ratio after using the technical solution of this application is given.

[0106] It can be seen from Figure 6 that the BER performance of high-speed users in the time-delay Doppler domain adopting the technical solution of this application is basically close to that under ideal channel estimation. Among them, in an environment with a relatively poor signal-to-noise ratio, this solution remains close to the case of ideal channel estimation; in an environment with a relatively good signal-to-noise ratio, the estimation result of this solution converges due to the influence of noise superposition on the estimation, but still has a relatively high degree of system reliability. Taking BER = 10 -2 as an example, the performance of high-speed users of this solution differs from that under ideal channel estimation by about 1 dB.

[0107] It can be seen from Figure 7 that the BER performance of low-speed users in the time-frequency domain of this solution is similar to that under ideal channel estimation and the performance trend is consistent. Taking BER = 0.03 as an example, the performance of low-speed users of this solution differs from that under ideal channel estimation by less than 1 dB. When the system orthogonally and parallelly transmits high-speed users and low-speed users, the overall performance of the system is still similar to that of ideal channel estimation and the convergence is consistent.

[0108] Through the above simulation analysis, the technical solution of this application can, while orthogonally and parallelly transmitting high-speed users and low-speed users, keep the transmission performance of high-speed users and low-speed users at a relatively ideal level.

[0109] Please refer to Figure 8 , Figure 8 which shows a communication device 80. The communication device 80 may include:

[0110] An acquisition module 801, configured to acquire a first symbol sent to a high-speed user and a second symbol sent to at least one low-speed user, where the high-speed user is a user with a moving speed exceeding a first threshold, and the at least one low-speed user is a user with a moving speed lower than the first threshold;

[0111] A first placement module 802, configured to place the first symbol in a plurality of resource blocks in the time-delay Doppler domain;

[0112] A conversion module 803, configured to convert the first symbol located in the time-delay Doppler domain into a third symbol located in the time-frequency domain, and the third symbol is distributed at different frequency domain positions in the time-frequency domain;

[0113] A second placement module 804, configured to place a second symbol in multiple resource blocks in the time-frequency domain to obtain a total transmission symbol located in the time-frequency domain, where the frequency-domain position of the second symbol is interleaved with the frequency-domain position of a third symbol;

[0114] A transmission module 805, configured to transmit the total transmission symbol.

[0115] In a specific implementation, the above communication device 80 may correspond to a chip with a communication function in a terminal device, such as a System-On-a-Chip (SOC), a baseband chip, etc.; or correspond to a chip module including a chip with a communication function in a terminal device; or correspond to a chip module with a data processing function chip, or correspond to a network device.

[0116] Other related descriptions of the communication device 80 may refer to the relevant descriptions in the foregoing embodiments, and will not be elaborated here.

[0117] An embodiment of the present application also discloses a channel estimation device, which may specifically include a receiving module and a channel estimation module. The receiving module is configured to receive a total received symbol, where the total received symbol is obtained after the total transmission symbol is transmitted through a wireless channel; the channel estimation module is configured to perform channel estimation on the channels of a high-speed user and at least one low-speed user respectively according to the total received symbol.

[0118] Regarding each device and product described in the above embodiments, each module / unit included therein can be a software module / unit, a hardware module / unit, or can be partially a software module / unit and partially a hardware module / unit. For example, for each device and product applied to or integrated into a chip, each module / unit included therein can be implemented in the form of hardware such as circuits. Or, at least some of the modules / units can be implemented in the form of software programs that run on a processor integrated inside the chip, and the remaining (if any) part of the modules / units can be implemented in the form of hardware such as circuits; for each device and product applied to or integrated into a chip module, each module / unit included therein can be implemented in the form of hardware such as circuits. Different modules / units can be located in the same component (such as a chip, a circuit module, etc.) or different components of the chip module. Or, at least some of the modules / units can be implemented in the form of software programs that run on a processor integrated inside the chip module, and the remaining (if any) part of the modules / units can be implemented in the form of hardware such as circuits; for each device and product applied to or integrated into a terminal device, each module / unit included therein can be implemented in the form of hardware such as circuits. Different modules / units can be located in the same component (such as a chip, a circuit module, etc.) or different components inside the terminal device. Or, at least some of the modules / units can be implemented in the form of software programs that run on a processor integrated inside the terminal device, and the remaining (if any) part of the modules / units can be implemented in the form of hardware such as circuits.

[0119] An embodiment of the present application also discloses a storage medium, which is a computer-readable storage medium, on which a computer program is stored. When the computer program runs, it can execute the steps of the method shown in the foregoing embodiments. The storage medium can include a read-only memory (ROM), a random access memory (RAM), a magnetic disk, an optical disk, etc. The storage medium can also include a non-volatile memory or a non-transitory memory, etc.

[0120] Please refer to Figure 9 , an embodiment of the present application also provides a schematic diagram of the hardware structure of a communication device. The device includes a processor 901, a memory 902, and a transceiver 903.

[0121] The processor 901 may be a general-purpose central processing unit (CPU), a microprocessor, an application-specific integrated circuit (ASIC), or one or more integrated circuits for controlling the execution of the program of the solution of the present application. The processor 901 may also include multiple CPUs, and the processor 901 may be a single-CPU processor or a multi-CPU processor. The processor here may refer to one or more devices, circuits, or processing cores for processing data (such as computer program instructions).

[0122] The memory 902 may be a ROM or other type of static storage device that can store static information and instructions, a RAM, or other type of dynamic storage device that can store information and instructions. It may also be an electrically erasable programmable read-only memory (EEPROM), a compact disc read-only memory (CD-ROM), or other optical disc storage, optical disc storage (including compact discs, laser discs, optical discs, digital versatile discs, Blu-ray discs, etc.), magnetic disk storage media, or any other medium that can be used to carry or store the desired program code in the form of instructions or data structures and can be accessed by a computer. The embodiments of the present application do not impose any restrictions on this. The memory 902 may exist independently (in this case, the memory 902 may be located outside the device or inside the device), or may be integrated with the processor 901. Among them, the memory 902 may contain computer program code. The processor 901 is used to execute the computer program code stored in the memory 902, so as to implement the method provided by the embodiments of the present application.

[0123] The processor 901, the memory 902, and the transceiver 903 are connected through a bus. The transceiver 903 is used to communicate with other devices or communication networks. Optionally, the transceiver 903 may include a transmitter and a receiver. The device in the transceiver 903 for implementing the receiving function may be regarded as a receiver, and the receiver is used to execute the receiving steps in the embodiments of the present application. The device in the transceiver 903 for implementing the sending function may be regarded as a transmitter, and the transmitter is used to execute the sending steps in the embodiments of the present application.

[0124] When Figure 9When the structural schematic diagram shown is used to illustrate the structure of the terminal device involved in the above embodiments, the processor 901 is used to control and manage the actions of the terminal device. For example, the processor 901 is used to support the network device in performing the actions executed in other processes described in the embodiments of the present application. The processor 901 can communicate with other network entities through the transceiver 903. For example, it communicates with the above-mentioned network device. The memory 902 is used to store the program code and data of the terminal device.

[0125] It should be understood that the term "and / or" in this article is only a description of the association relationship between associated objects, indicating that there can be three relationships. For example, A and / or B can represent: A exists alone, A and B exist simultaneously, and B exists alone. In addition, the character " / " in this article indicates that the associated objects before and after are in an "or" relationship.

[0126] The term "a plurality of" that appears in the embodiments of the present application refers to two or more.

[0127] The descriptions such as the first and the second that appear in the embodiments of the present application are only for schematic and distinguishing description objects, without an order, and do not represent a special limitation on the number of devices in the embodiments of the present application, and cannot constitute any limitation to the embodiments of the present application.

[0128] The "connection" that appears in the embodiments of the present application refers to various connection methods such as direct connection or indirect connection to achieve communication between devices, and the embodiments of the present application do not make any limitations on this.

[0129] The above embodiments can be implemented in whole or in part by software, hardware, firmware, or any other combination. When implemented using software, the above embodiments can be implemented in whole or in part in the form of a computer program product. The computer program product includes one or more computer instructions or computer programs. When the computer instructions or computer programs are loaded or executed on the computer, the processes or functions described in the embodiments of the present application are generated in whole or in part. The computer can be a general-purpose computer, a special-purpose computer, a computer network, or other programmable devices. The computer instructions can be stored in a computer-readable storage medium, or transmitted from one computer-readable storage medium to another computer-readable storage medium. For example, the computer instructions can be transmitted from one website, computer, server, or data center to another website, computer, server, or data center in a wired or wireless manner.

[0130] It should be understood that in various embodiments of the present application, the magnitudes of the serial numbers of the above processes do not mean the order of execution. The execution order of each process should be determined by its function and internal logic, and should not constitute any limitation to the implementation process of the embodiments of the present application.

[0131] In several embodiments provided by the present application, it should be understood that the disclosed methods, devices, and systems can be implemented in other ways. For example, the device embodiments described above are merely illustrative; for example, the division of the units is only a logical function division, and there can be other division methods in actual implementation; for example, multiple units or components can be combined or integrated into another system, or some features can be ignored or not executed. Another point is that the displayed or discussed couplings or direct couplings or communication connections to each other can be through some interfaces, and the indirect couplings or communication connections of the devices or units can be in electrical, mechanical, or other forms.

[0132] The units described as separate components may or may not be physically separated, and the components displayed as units may or may not be physical units, that is, they can be located in one place or distributed to multiple network units. Some or all of the units can be selected according to actual needs to achieve the purpose of the solution of this embodiment.

[0133] In addition, the functional units in each embodiment of the present application can be integrated in a processing unit, or each unit can be physically included separately, or two or more units can be integrated in one unit. The above integrated units can be implemented in the form of hardware or in the form of hardware plus software functional units.

[0134] The above integrated units implemented in the form of software functional units can be stored in a computer-readable storage medium. The above software functional units stored in a storage medium include several instructions for causing a computer device (which can be a personal computer, a server, or a network device, etc.) to execute some steps of the methods described in each embodiment of the present application.

[0135] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application. Therefore, the protection scope of the present application should be subject to the scope defined by the claims.

Claims

1. A communication method, characterized in that, Including: Obtaining a first symbol sent to a high-speed user and a second symbol sent to at least one low-speed user, where the high-speed user is a user with a moving speed exceeding a first threshold, and the at least one low-speed user is a user with a moving speed lower than the first threshold; Placing the first symbol in a plurality of resource blocks in the time-delay Doppler domain; Converting the first symbol located in the time-delay Doppler domain into a third symbol located in the time-frequency domain, and the third symbol is distributed at different frequency-domain positions in the time-frequency domain; Placing the second symbol in a plurality of resource blocks in the time-frequency domain to obtain a total transmission symbol located in the time-frequency domain, and the frequency-domain position where the second symbol is located is interleaved with the frequency-domain position where the third symbol is located; Transmitting the total transmission symbol.

2. The communication method according to claim 1, wherein The first pilot symbols in the third symbol are located at the same one or more time-domain positions, and the second pilot symbols in the second symbol are located at the one or more time-domain positions.

3. The communication method according to claim 1, wherein The placing the first symbol in a plurality of resource blocks in the time-delay Doppler domain includes: Dividing M×N first resource blocks in the time-delay Doppler domain into p×q second resource blocks, where M, N, p, and q are all positive integers, and M is divisible by p, and N is divisible by q; Placing the first symbol in a target second resource block, and the first symbol includes data symbols, pilot symbols, and guard interval symbols; Repeatedly placing the target second resource block in the first resource block after rotating it according to a target rotation factor.

4. The communication method according to claim 3, wherein The repeatedly placing the target second resource block in the first resource block after rotating it according to a target rotation factor includes: Repeatedly placing the rotated target second resource block p times in the time-delay dimension and q times in the Doppler dimension in the first resource block.

5. The communication method according to claim 3, wherein Rotating the target second resource block using the following formula: Among them, represents the rotated target first resource block, where l = 0, …, M - 1, k = 0, …, N - 1, represents the target second resource block, where l′ = 0, …, M / p - 1, k′ = 0, …, N / q - 1, c = 0, …, p - 1, d = 0, …, q - 1, index = 1, (·) p represents the modulo operation with respect to p, represents the floor operation.

6. The communication method according to claim 1, characterized in that, The time interval between adjacent second pilot symbols in the second symbol is inversely proportional to the Doppler frequency of the channel.

7. A channel estimation method based on the communication method according to any one of claims 1 to 6, characterized in that Including: Receiving a total received symbol, where the total received symbol is obtained after the total transmission symbol is transmitted through a wireless channel; Performing channel estimation on the channels of the high-speed user and the at least one low-speed user according to the total received symbol.

8. The channel estimation method according to claim 7, wherein The performing channel estimation on the channels of the high-speed user and the low-speed user according to the total received symbol includes: Detecting the first symbol by using the second symbol as noise in the time-delay Doppler domain, and performing channel estimation on the high-speed user according to the detected first symbol; Deleting the detected first symbol in the time-delay Doppler domain, and converting the remaining second symbol to the time-frequency domain to perform channel estimation on the at least one low-speed user.

9. A communication device, characterized in that, Including: An obtaining module, configured to obtain a first symbol sent to a high-speed user and a second symbol sent to at least one low-speed user, where the high-speed user is a user with a moving speed exceeding a first threshold, and the at least one low-speed user is a user with a moving speed lower than the first threshold; A first placing module, configured to place the first symbol in a plurality of resource blocks in the time-delay Doppler domain; A conversion module, configured to convert the first symbol in the time-delay Doppler domain into a third symbol in the time-frequency domain, and the third symbol is distributed at different frequency domain positions in the time-frequency domain; A second placement module, configured to place the second symbol in a plurality of resource blocks in the time-frequency domain to obtain a total transmission symbol in the time-frequency domain, and the frequency domain position where the second symbol is located is interleaved with the frequency domain position where the third symbol is located; A transmission module, configured to transmit the total transmission symbol.

10. A channel estimation device for the communication method according to any one of claims 1 to 6, characterized in that, Comprising: A receiving module, configured to receive a total received symbol, where the total received symbol is obtained after the total transmission symbol is transmitted through a wireless channel; A channel estimation module, configured to respectively perform channel estimation on the channels of the high-speed user and the at least one low-speed user according to the total received symbol.

11. A computer-readable storage medium having a computer program stored thereon, characterized in that, When the computer program is run by a processor, it executes the steps of the communication method according to any one of claims 1 to 6, or executes the steps of the channel estimation method according to claim 7 or 8.

12. A communication device, comprising a memory and a processor, wherein a computer program that can run on the processor is stored on the memory, characterized in that, When the processor runs the computer program, it executes the steps of the communication method according to any one of claims 1 to 6, or executes the steps of the channel estimation method according to claim 7 or 8.

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