Spatial multiplexing with a single transmitter over a wideband channel

Abstract

An apparatus comprising a wireless interface configured to wirelessly transmit a signal to a receiver; and a precoder unit configured to obtain a first data signal to be transmitted and a second data signal to be transmitted; and configured to perform a first multi-path precoding on the first data signal in accordance with a first set of paths between the apparatus and the receiver to obtain a first precoded signal; and configured to perform a second multi-path precoding on the second data signal in accordance with a second set of paths between the apparatus and the receiver to obtain a second precoded signal; wherein the precoder unit is configured to generate the first precoded signal and the second precoded signal such that the second precoded signal is delayed relative to the first precoded signal at the receiver. The apparatus is configured to transmit the first precoded signal and the second precoded signal with the same transmission radiation characteristic.

Description

Technical Field

[0001] This application relates to the field of wireless communication systems or networks, more particularly to the enhancement of communication between network entities of a communication network, and specifically to a transceiver concept for spatial multiplexing with a single transmitter over a broadband channel. Background Technology

[0002] Figure 1 This is a schematic diagram of an example of a terrestrial wireless network 100, as shown below. Figure 1 As shown in (a), it includes a core network 102 and one or more radio access networks RAN1, RAN2, ... RAN N . Figure 1 (b) is a schematic diagram of an example radio access network (RANn) that may include one or more base stations gNB1 to gNB5, each serving a specific area around the base station schematically shown by corresponding cells 1061 to 1065. The base stations are provided to serve users within the cell. One or more base stations may provide service to users on licensed and / or unlicensed bands. The term base station, BS, refers to gNB in ​​a 5G network, eNB in ​​UMTS / LTE / LTE-A / LTE-A Pro, or simply BS in other mobile communication standards. Users may be fixed or mobile devices. Base stations may be fixed or mobile devices, such as base stations mounted on drones, vehicles, balloons, relays (virtual antennas of base stations located elsewhere), or (LEO) satellites. The wireless communication system may also be accessed by mobile or fixed IoT devices connected to the base station or users. Mobile devices or IoT devices can include physical devices, such as ground-based vehicles like robots or cars, aircraft such as manned or unmanned aerial vehicles (UAVs), the latter also known as unmanned aircraft, buildings, and other items or devices that have embedded electronic devices, software, sensors, actuators, etc., and network connectivity that enables these devices to collect and exchange data on existing network infrastructure. Figure 1 (b) shows an exemplary view of five cells; however, RANn may include more or fewer such cells, and RANn may also include only one base station. Figure 1(b) shows two user UEs, UE1 and UE2, located in cell 1062 and served by base station gNB2, also referred to as user equipment UEs. Another user UE3 is shown in cell 1064, served by base station gNB4. Arrows 1081, 1082, and 1083 schematically represent uplink / downlink connections used for transmitting data from users UE1, UE2, and UE3 to base stations gNB2 and gNB4, or for transmitting data from base stations gNB2 and gNB4 to users UE1, UE2, and UE3. This can be implemented on licensed or unlicensed frequency bands. Furthermore, Figure 1 (b) illustrates two IoT devices 1101 and 1102 in cell 1064, which can be fixed or mobile devices. IoT device 1101 accesses the wireless communication system via base station gNB4 to receive and send data, as schematically indicated by arrow 1121. IoT device 1102 accesses the wireless communication system via user UE3, as schematically indicated by arrow 1122. Each base station gNB1 to gNB5 can connect to the core network 102, for example via the S1 interface, via corresponding backhaul links 1141 to 1145, which... Figure 1 (b) is schematically represented by an arrow pointing to the "core". The core network 102 can connect to one or more external networks. Furthermore, some or all of the individual base stations gNB1 to gNB5 can be interconnected via their respective backhaul links 1161 to 1165, for example, via the S1 or X2 interface or XN interface in the NR. Figure 1 (b) is schematically represented by an arrow pointing to “gNBs”.

[0003] For data transmission, a physical resource grid can be used. A physical resource grid can include a set of resource elements to which various physical channels and physical signals are mapped. For example, physical channels can include physical downlink, uplink, and sidelink shared channels (PDSCH, PUSCH, PSSCH) carrying user-specific data, also known as downlink, uplink, and sidelink payload data; physical broadcast channels (PBCH) carrying, for example, Master Information Block (MIB) and System Information Block (SIB); and physical downlink, uplink, and sidelink control channels (PDCCH, PUCCH, PSSCH) carrying, for example, downlink control information (DCI), uplink control information (UCI), and sidelink control information (SCI). For uplink, physical channels can further include physical random access channels (PRACH or RACH), which allow the UE to access the network once it has synchronized and acquired the MIB and SIB. Physical signals can include reference signals or symbols (RS), synchronization signals, etc. A resource grid can include frames or radio frames with a specific duration in the time domain and a given bandwidth in the frequency domain. A frame can have a number of subframes of a predetermined length, for example, 1 millisecond. Each subframe can include 12 or 14 OFDM symbols from one or more time slots, depending on the cyclic prefix (CP) length. A frame can also include fewer OFDM symbols, for example, when using a shortened transmission time interval (sTTI) or a micro-slotted / non-slotted frame structure that includes only a few OFDM symbols.

[0004] The wireless communication system can be any single-tone or multi-carrier system using frequency division multiplexing, such as orthogonal frequency division multiplexing (OFDM), orthogonal frequency division multiple access (OFDMA), or any other IFFT-based signal with or without CP, such as DFT-s-OFDM. Other waveforms, such as non-orthogonal waveforms used for multiple access, can be used, for example, using filter bank multicarrier (FBMC), generalized frequency division multiplexing (GFDM), or universal filtered multicarrier (UFMC). The wireless communication system can operate, for example, according to the LTE-Advanced pro standard, or 5G, or NR (New Radio) standard, or NR-U, or New Radio Unlicensed standard.

[0005] Figure 1 The wireless network or communication system described herein can be a heterogeneous network with different overlapping networks, such as a macro cell network, where each macro cell includes a network of macro base stations such as gNB1 to gNB5 and small cell base stations such as femtocells or picocells. Figure 1 (Not shown in the image).

[0006] In addition to the aforementioned terrestrial wireless networks, non-terrestrial wireless communication networks also exist, including spaceborne transceivers such as satellites, and / or airborne transceivers such as unmanned aerial vehicle (UAV) systems. Non-terrestrial wireless communication networks or systems can be referenced in conjunction with the above. Figure 1 The described land systems operate in a similar manner, for example, according to the LTE-Advanced Pro standard or the new 5G or NR radio standards.

[0007] Note that the information in the above sections is only used to enhance the understanding of the background of the present invention, and therefore may contain information that does not constitute prior art known to those skilled in the art.

[0008] Starting with the existing technology as described above, it may be necessary to improve data transmission, i.e., to increase the data throughput of wireless communication networks. Attached Figure Description

[0009] The embodiments of the present invention will now be described in further detail with reference to the accompanying drawings:

[0010] Figure 1 A schematic diagram illustrating an example of a wireless communication system is shown;

[0011] Figure 2 This is a schematic diagram of a wireless communication system that includes a transmitter and one or more receivers;

[0012] Figure 3a A schematic block diagram of a wireless communication network according to an embodiment is shown;

[0013] Figure 3b It shows in Figure 3a A schematic block diagram of communication performed in a wireless communication network;

[0014] Figure 4a A schematic diagram of multi-user media access control in a multi-user (MU) - single-input multiple-output (SIMO) configuration is shown.

[0015] Figure 4b A schematic diagram of a multi-user multiple-input multiple-output (MIMO) MAC is shown;

[0016] Figure 5a A schematic diagram of a multi-user broadcast channel in MU-MISO (Multiple-Input Single-Output) broadcasting is shown;

[0017] Figure 5b A schematic diagram of MU-MIMO broadcasting is shown;

[0018] Figure 6a -f illustrates the energy in both line-of-sight (LOS) and non-LOS paths;

[0019] Figure 7This is a schematic diagram of normalized power in a signal that is ideally matched to the channel according to an embodiment;

[0020] Figure 8 This is a schematic diagram of the normalized power in a signal having two delayed components according to an embodiment;

[0021] Figure 9 This is a schematic diagram of a transmitter-side windowing method for shortening the applied channel impulse response according to an embodiment;

[0022] Figure 10 Based on the embodiments Figure 9 Examples of the original and shortened channel impulse response of the technique;

[0023] Figure 11 An example of a computer system is shown on which the units or modules and steps of the method described in the present invention can be executed.

[0024] Figure 12a A schematic block diagram of at least a portion of a communication network is shown, in which devices precode signals based on channel conditions or path groups to different receivers;

[0025] Figure 12b A schematic block diagram of at least a portion of a communication network is shown, wherein two or more devices act as transmitters of signals, and a receiver receives two signals; and

[0026] Figure 12c It shows the combination of Figure 12a and Figure 12b A schematic block diagram of at least a portion of the communication network of an embodiment. Detailed Implementation

[0027] Embodiments of the invention will now be described in more detail with reference to the accompanying drawings, wherein the same or similar elements have the same reference numerals.

[0028] Embodiments of the present invention may be as follows: Figure 1 The description includes implementations in wireless communication systems involving base stations and users, such as mobile terminals or IoT devices. Figure 2 This is a schematic diagram of a wireless communication system, including a transmitter 400, such as a base station, and one or more receivers 4021 to 402. n Such as a user equipment (UE). Transmitter 400 and receiver 402 can communicate via one or more wireless communication links or channels 404a, 404b, 404c, such as radio links. Transmitter 400 may include one or more antennas ANT coupled to each other. TAlternatively, it may include an antenna array with multiple antenna elements, a signal processor 400a, and a transceiver 400b. The receiver 402 includes one or more antennas ANTs coupled to each other. R Or an antenna array with multiple antennas, signal processors 402a1, 402a n and transceivers 402b1, 402b n Base station 400 and UE 402 can communicate via corresponding first wireless communication links 404a and 404b, such as radio links using Uu interfaces, while UE 402 can communicate with each other via a second wireless communication link 404c, such as a radio link using a PC5 interface. When UEs are not served by the base station and are not connected to the base station, for example, when they are not in an RRC connection state, or more generally, when there is no SL resource allocation configuration or assistance provided by the base station, UEs can communicate with each other via sidelinks. The system, one or more UEs 402, and base station 400 can operate in accordance with the teachings of the invention described herein.

[0029] Beamforming is a known technique in mobile communication systems. Beamforming involves forming and guiding one or more lobes and / or nulls along a given direction using a set of antenna structures, antenna panels, antenna arrays, etc. By using beamforming, individual data signals can be transmitted in different directions, thus taking advantage of multipath propagation to one or more receivers.

[0030] The embodiments described herein relate to precoding different signals to be transmitted simultaneously according to different multipath components. For illustrative reasons, some embodiments are described as implementing precoding to achieve an offset in time or a delay in the delay domain, such that the signal arrives at the receiver with a delay. However, the embodiments are not limited to achieving a delay, but also relate to an offset in the Doppler domain, which may be implemented alternatively or in addition to the delay. That is, the embodiments relate to precoding different signals differently to include an offset in the delay / Doppler domain at the receiver. Furthermore, in the event of relative movement between the transmitter and receiver, some paths used for multipath propagation may remain (almost) unchanged.

[0031] When assessing channel state, assessments based on delay and / or Doppler shift may be more time-stable compared to phase shift and similar metrics.

[0032] The embodiments described herein relate to structures or radiation patterns that benefit from the same or similar advantages without altering the shape of the beam. These embodiments can be understood as simulating or replicating the multipath propagation of different data signals by implementing offsets in the delay / Doppler domain between data signals, such that at the receiver of the data signals, the same or at least similar results can be obtained even if the transmitter does not perform dynamic beamforming.

[0033] The embodiments involve using the same transmit radiation characteristics to transmit a first precoded signal and a second precoded signal. As "same transmit radiation characteristics," it can be understood that the radiation characteristics have the same or at least similar directionality and / or the same or at least similar polarization. Similar directionality can be understood as having lobes that cover or point towards the receiver, for example, this is correct for an omnidirectional radiation pattern. Furthermore, this includes slightly altering the direction or location of the formed lobes, for example, when the maximum radiated power varies slightly as it propagates in space while the receiver remains within the lobe. This can be understood as using the same transmission beam and / or transmission polarization, while not excluding minor variations therein.

[0034] Figure 3a A schematic block diagram of a wireless communication network according to an embodiment is shown. The wireless communication network 300 includes a device 302, which may be a device used in the wireless communication network 100, such as a UE, a base station, an IoT device, etc.

[0035] Device 302 can be configured, for example, to transmit signals within wireless communication network 300 to communicate with receiver 304. Receiver 304 can be implemented to utilize multipath propagation in wireless communication network 300, which can be achieved through different clusters 3061 to 306 that allow for individual scattering and / or channel delay. i Obtained. Device 304 may be a receiving device, such as a device configured for separating spatial data streams or performing beamforming, such as a UE or base station.

[0036] Device 302 includes a wireless interface 308. The wireless interface 308 may include one or more antennas, antenna elements, panels, configurations, antenna groups, and / or panels, or combinations thereof. Device 302 includes a combination of... Figure 3b The pre-encoder unit 312 is explained in more detail.

[0037] Figure 3b It shows in Figure 3a This is a schematic block diagram of communication performed in a wireless communication network 300. Specifically, refer to pre-encoder unit 312. Pre-encoder unit 312 is configured to acquire data signals 3141 and 3142. Data signals 3141 and 3142 can be obtained, for example, from converter units 3161 and 3162, respectively configured to transform the frequency domain representation of data signal 3141 into a time domain representation. Alternatively, pre-encoder unit 312 can receive the frequency domain representation. Optionally, converter units 3161 and / or 3162 can be implemented as part of pre-encoder unit 312.

[0038] Data signals 3141 and 3142 can be pre-coded to obtain pre-coded data signals 3221 and 3222 using pre-encoder entities 3181 and 3182 respectively. Pre-encoder entities 3181 and 3182 can be configured to pre-encode corresponding data signals 3141 and 3142 according to a corresponding set of paths 324 between devices 302 and 306. Pre-encoder units 3181 and 3182 can be implemented, for example, as matched filters. First and second subsets, each having multiple at least two paths 324, can be selected from a plurality of distinguishable paths, for example, at least two, at least three, at least five, at least ten, or even more. That is, each pre-encoder entity 318 is configured to implement multipath pre-coding of the corresponding data signals 3141 and 3142. Signals 3221 and 3222 can be transmitted within the same or at least associated frequency range, i.e., in an analog multipath or multibeam transmission manner. The set of selected paths can be equal, but can also vary relative to at least one path until a set of paths is selected such that the set of paths is disjoint. Different sets of paths can be selected such that signals 3221 and 3222 interfere with each other with a low amount or even a minimal amount.

[0039] The pre-encoder unit 312 can be configured to obtain a pre-coded signal 3221 based on a first matched filter 3181, for example, a filter matched with the multipath components of a first set of paths. The pre-encoder unit 312 can also be configured to obtain a pre-coded signal 3222 based on another filter 3182 matched with the multipath components of a second set of paths. That is, pre-encoder entities 3181 and 3182 can be implemented as matched filters.

[0040] Device 302 can be configured to obtain channel impulse response information indicating the multipath components of a first set of paths and the multipath components of a second set of paths. For example, the device can receive or determine the channel impulse response providing all naming information. The device can obtain the information based on pilot / reference symbols previously transmitted in the uplink and / or downlink directions. Alternatively or additionally, the device can obtain the information based on information indicating a representation of the radio channel, such as transforming complex coefficients to a suitable domain to represent the radio channel, e.g., time domain, frequency domain, time-frequency domain, delay / Doppler domain, and / or spatial domain, where angular transmit spectrum and / or angular receive spectrum can be provided, e.g., based on the direction of arrival (DoA) or the direction of departure (DoD). Alternatively or additionally, the device can obtain the information based on a report from a receiver, i.e., the receiver can provide the requested information. Alternatively or additionally, the device can have prior knowledge of the channel impulse response information, e.g., when a time-invariant channel is present or when such a channel is assumed. Reports received from the receiver can be compressed using lossless or lossy decompression. Alternatively or additionally, the report may include a description of the radio propagation environment, for example, in the form of MPC (Multipath Component) and / or using filter coefficients / transmission strategies applied at the transmitter using a specific precoder. The latter may resemble codebook-based precoding, where precoder units are instructed to apply appropriate precoding techniques, and the meaning of codebook entries is pre-agreed.

[0041] Pre-encoder unit 312 is configured to generate pre-encoded signals 3221 and 3222, such that pre-encoded signal 3222 is offset in the delay / Doppler domain relative to pre-encoded signal 3221. Pre-encoder unit 312 may include offset unit 326 to offset the output of pre-encoder entity 3182 in the delay / Doppler domain, for example, by implementing a time delay or frequency / Doppler shift, the output represented as signal 3222'. Although delay unit 326 is represented as part of pre-encoder unit 312, offset unit 326 may also be a separate entity and / or may be implemented as part of pre-encoder entity 3182. For example, to implement the offset, a ZAK transform may be used.

[0042] The delay obtained in the precoded signal 3222 is related to the delay that is perceptible or effective at device 304. According to an embodiment, the precoder unit can be configured to obtain a precoded signal 3222 with a delay relative to the precoded signal 3221, such that, within a tolerance of, for example, up to 30%, up to 20%, or 10%, or even less, the delay corresponds to one of the fractions or algebraic fractions of the symbol duration, such as a / b of the OFDM symbol length. Alternatively, the delay e can be a fraction of the length of the guard interval within the said tolerance range. An integer ratio can be selected such that the delay is at least a sampling distance in the analog / digital / conversion (ADC) or an equivalent representation in the digital domain. This equivalent representation may be the result of filtering stages in the ADC unit, which use intermediate sampling or shift sampling but provide a certain amount of effective sampling for digital signal processing in the receiver unit. A fraction or algebraic fraction can be understood as an operation of dividing a first real value by a second real value.

[0043] According to the embodiment, the delay to be implemented can be selected to correspond to the following within the tolerance range:

[0044] - An algebraic fraction of the duration of the symbol;

[0045] - An algebraic fraction of the length of the protection interval;

[0046] - The algebraic fraction or multiple of the correlation or effective length of the channel impulse response between the device and the receiver; and

[0047] - A multiple of the sampling rate of the pre-encoder unit;

[0048] According to the embodiment, the offset in the Doppler domain to be implemented can be selected so that it corresponds to the following within the tolerance range:

[0049] - The algebraic fraction of the effective Doppler shift in the correlated Doppler spectrum;

[0050] - Algebraic fraction of the length of the correlated channel impulse response

[0051] - An algebraic fraction or multiple of the subcarrier spacing of the wireless network in which the device operates; and

[0052] - Algebraic fraction of the system bandwidth of the wireless network in which the device operates

[0053] The offset in the Doppler domain may be greater than the subcarrier spacing. For example, it may be at most the modulation system bandwidth or the maximum Doppler spread.

[0054] The fraction of the effective Doppler frequency shift in the correlated Doppler spectrum may be equivalent to the effective channel impulse response.

[0055] In other words, by delaying signal 3222 in time relative to precoded signal 3221, device 304 can receive signals 3221 and 3222 as if they were transmitted via different beams in different directions. By applying precoded signals 3221 and 3222 to wireless interface 308 to combine precoded signals 3221 and 3222 to obtain combined signal 332 through channel 328, the signal and external interference 334, represented as additive white Gaussian noise (AWGN), can be further affected before the signal reaches receiver 304.

[0056] Device 302 is configured to transmit precoded signals 3221 and 3222 having the same transmission radiation characteristics as wireless interface 308. That is, if device 302 is capable of beamforming, it uses the same beam or beamforming configuration to transmit the precoded signals 3221 and 3222. If device 302 is not capable of beamforming, the implemented radiation and / or transmission characteristics are used.

[0057] Therefore, device 302 can use a single beam or a subset of a beam set that can be formed with a device having the transmitting radiation characteristics of wireless interface 308 to simulate the multi-beam transmission of signals 3221 and 3222.

[0058] Notice, Figure 3b The order of the components shown is not a limitation of the embodiment. For example, IFFT may not be performed to generate input for the pre-encoder; IFFT may be performed after pre-encoding or may be skipped, for example, when signals X1 and / or X2 are provided in the time domain. Alternatively or additionally, offset unit 326 may be implemented before pre-encoder 3182 and / or before converter unit 3162.

[0059] When transmitting data between a wireless transmitter and a wireless receiver, improvements in spectral efficiency for each channel can be achieved through various means, such as high code rates, higher-order modulation (e.g., QPSK, M-QAM), AOM (angular orbital momentum) over a finite distance, and spatial multiplexing (MIMO) with a system SINR > 10 dB.

[0060] In the latter case, spatial multiplexing and MIMO (MUX) multi-antenna configurations are used on both the transmitter and receiver sides to create multiple-input multiple-output channels. 5G radio systems, considering transmissions in millimeter-wave bands such as FR2 (24-52 GHz), require so-called beamforming on both the transmitter and receiver sides to achieve sufficient coverage for the radio link. This is typically accomplished by multiple array antennas integrated into an antenna panel, allowing the energy to be focused for transmission or reception by using a combined network of phase shifters and / or attenuators for each antenna element or group of antenna elements, coherently stimulating or receiving several or all antenna elements of the panel. Spatial and energy constraints in end-user equipment (UEs) led to the consensus in 3GPP standard Rel-15 that a UE can only use one beam for transmission at a time, and that transmitting multiple spatial data streams from a single UE is not supported. The solution proposed in this invention disclosure enables a UE / transmitter with a single spatial beam to transmit multiple spatial streams simultaneously by mapping multiple spatial streams to different delay characteristics of the propagation channel connecting the transmitter and receiver locations. By utilizing this method, the spectral efficiency per channel can be increased for a specific user / UE or a group of UEs.

[0061] The proposed solution is relevant to any type of communication system that allows the utilization of multipath resolution, or due to the large signal bandwidth used for transmission, such as Nx100MHz or 1GHz or higher, or transmission systems with sufficiently high signal sampling rates, allowing for targeted excitation or matching of the MPC of the propagation channel, such as a 100MHz transmission bandwidth with Nx100MHz sampling, at least high enough to obtain good time path resolution. The proposed solution is particularly suitable for the following application scenarios:

[0062] (1) Single Tx and multiple Rx – similar to narrowband MIMO:

[0063] A communication system having a transmitter equipped with a single transmit antenna and a receiver equipped with multiple antennas, wherein the transmitter precodes multiple streams by means of a time-delay precoder that matches the multipath components of the propagation channel, so that the receiver can separate the signals by their spatial and / or temporal characteristics.

[0064] (2) Single Tx and single Rx-tap delay linear filters to separate the streams located at T0 and T1:

[0065] A communication system having a transmitter equipped with a single transmit antenna and a single receive antenna, wherein the transmitter precodes multiple streams by a time-delay precoder matched to the multipath components of the propagation channel, so that the receiver can separate the signals by their time characteristics.

[0066] (3) MU-MIMO using coordinated TD-MUX filters at multiple Tx points in the uplink

[0067] A communication system having multiple transmitters, each equipped with a single transmit antenna, and receivers using one or more receive antennas, wherein the transmitters precode a single or multiple streams using a time-delay precoder matched to the multipath components of an extended MU-MIMO / MU-MISO propagation channel, so that the receiver can separate the signal by its temporal and / or spatial characteristics. The delay precoders of the multiple UEs should preferably be synchronized; otherwise, a feedback mechanism for optimizing delay precoder adjustments is required between the receiver and the transmitting multiple UEs.

[0068] Depending on whether the receiver is equipped with a single effective receive antenna (e.g., an omnidirectional antenna, a horn antenna, or an antenna array forming a receive beam) or multiple receive antenna ports, delay precoding is necessary so that multiple streams can be used separately, for example, in the time domain only (single receive antenna) or in the time and / or spatial domains (multiple receive antennas). Separation in the spatial domain means that the same tap or narrowband channels with equal frequencies experience phase and / or amplitude differences in OFDM at, for example, different receive antennas, thus allowing the application of MIMO signal processing techniques. Alternatively, this can be implemented alternatively or additionally in the downlink.

[0069] (4) Multiple TRPs in the downlink (DL) to a receiver with a single Rx antenna

[0070] A communication system with distributed transmitters, each equipped with a single transmit antenna and a single receive antenna at the UE in the downlink (DL), where each transmitter precodes one or more streams individually or jointly (joint precoding requires not only time synchronization between TRPs but also phase synchronization for coherent delay precoding—this is similar to or equivalent to coherent CoMP (Coordinated Multipoint) in the DL). When coherent CoMP is applied in the DL, the effective channel becomes a single-tap channel with a flat frequency response if optimization is performed. The only difference is that the SNR of each OFDM subcarrier depends on the quality of the narrowband MIMO channel, matched to the multipath components of the propagation channel by a time-delay precoder so that the receiver can separate the signals transmitted from different TRPs by their time characteristics. For this transmission scheme, the precoders must be time-synchronized at least in terms of the applied windowing. Furthermore, joint or distributed power allocation helps optimize MUX performance. Due to the macroscopic separation of multiple TRPs or different MPCs or under different access delays, a richer multipath channel with potentially longer effective access delays can be utilized in delay precoding schemes.

[0071] (5) Multiple TRPs in the downlink (DL) to multiple receivers with one or more Rx antennas

[0072] A communication system with distributed transmitters, each equipped with a single transmit antenna, and receivers on the UE side in the downlink (DL) with one or more receive antennas, wherein each transmitter individually or jointly precodes one or more streams (jointly requiring not only time synchronization between TRPs, but also phase synchronization even for coherent delay precoding—which would be similar to or equivalent to coherent CoMP in DL), using a time-delay precoder matched to the multipath components of the propagation channel, so that the receiver can separate the transmitted signal from different TRPs by their temporal and / or spatial (multiple receiver) characteristics. In this multi-user DL scenario, each receiver should receive its intended signal / stream with improved SINR compared to no-delay precoding. This is achieved by delaying the signal used for each UE receiver, which allows the effective channel taps used for each UE receiver to be separated in the time domain by windowing and / or in the spatial domain by sufficient phase difference between the multiple receive antennas of each UE, thus performing MIMO signal processing.

[0073] For this transmission scheme, the precoder must be time-synchronized, at least in terms of the applied delay windowing. Furthermore, joint or distributed power allocation helps optimize MUX performance. Due to the macroscopic separation of multiple TRPs or different MPCs, or under different access delays, a richer multipath channel with potentially longer effective access delays can be utilized in delay precoding schemes. Appropriate delay distribution with overall channel matching among multiple TRPs and multiple UEs allows for globally effective block-by-block channel orthogonalization among users in the DL, achieving at least a lateral SIR > 10 dB, justifying spatial multiplexing.

[0074] So far, how has this problem been solved?

[0075] To date, MIMO has always required the use of multiple antennas on both the transmitting and receiving sides. A classic example is:

[0076] - Narrowband single-user MIMO (SU-MIMO) between a multi-antenna transmitter and a multi-antenna receiver, where all processing is performed at the receiver and / or transmitter.

[0077] Multi-user MIMO (MU-MIMO) is a base station (BS) that can have multiple antennas, and a terminal / UE that has one or more antennas. Most of the processing is done on the receiver and / or transmitter side equipped with multiple antennas.

[0078] - Wideband MIMO or MIMO-OFDM applies the same technology as described above, but uses OFDM to divide the wideband MIMO channel into many parallel narrowband MIMO channels without generating inter-channel interference (even in a multipath environment, given moderate mobility / Tx / Rx / relative velocity of reflecting objects in the propagation environment, CP-OFDM subcarriers remain orthogonal).

[0079] Time-reversed (TR) precoding has been popularized due to its simplicity, particularly on the receiver side, as only a single tapped filter is needed on the detector side. An example of the idea behind TR precoding is using the conjugate inverse of the tapped-delay channel as a precoder. Therefore, the effective channel observed by the receiver is the autocorrelation function of the channel, resulting from the convolution of the channel with its conjugate inverse. However, precoding can also be performed in the frequency domain, leading OFDM systems to use the power-scaled conjugate of each subchannel as a precoder, similar to MRT precoding [Lo99].

[0080] TR precoding in scientific literature:

[0081] Experimental studies of TR precoding are shown in [EKPP10], demonstrating its practical applicability in measurements. Key facts: 250MHz bandwidth at a center frequency of 2.45GHz. See [EKPP10] Figure 6a -d indicates the effect of TR precoding on the channel impulse response (CIR). SU-MIMO, MU-MIMO

[0082] Experimental results for a 380MHz bandwidth at a 680MHz center frequency (spanning 490MHz to 870MHz) are also shown in [WWH+11]. The text paragraphs based on [HYW+11] introduce applications of Time Reversed Division Multiplexing (TRDM), but only in the context of multiple users distinguishable by unrelated tap delay profiles or channel responses.

[0083] • In [HYW+11], the time-reversal division multiple access scheme in a multipath channel has already been introduced. Similarly, considering multiple users in the case of a single antenna, our approach is significantly different from that in [HYW+11].

[0084] ● In [FTY12], TR precoding is applied to MISO and MIMO systems.

[0085] • In [DHCG13] and [MHML15], the MISO / MIMO OFDM precoding scheme was considered.

[0086] • A SIMO system was considered in [TH15]. A novel TR precoder was proposed based on the receive covariance matrix of a multi-antenna receiver. According to the formula in [TH15], the number of data streams that can be transmitted is equal to the number of receiving antennas. Wrt This invention clarifies that the scheme in [TH15] cannot send more than one stream to a receiver with a single antenna, therefore this invention is not included in [TH15]. The TR transmission scheme is taken from [WWH+11].

[0087] TR precoding in patent documents:

[0088] - [HL17], titled "Multi-user Time-Reversal Partial Multiple Access Uplink System with Parallel Interference Cancellation"

[0089] - The first statement was based on multiple users, so it does not conflict with the idea we put forward.

[0090] Additional notes:

[0091] -with subcarrier bandwidth B (SC) For example, B as a "standard" LTE configuration (SC) =15kHz, our symbol rate / duration is If the symbol rate T (SY) Delay τ greater than CIR L This makes T (SY) >τ L This avoids ISI. Please note that τ L This represents the delay of the Lth path, specifically the path with the maximum delay when the amplitude exceeds a certain threshold, such as hot + receiver noise. In the example in the literature, the symbol rate is much greater than the CIR, making T... (SY) >>τ L This is a valid assumption for 5G OFDM systems.

[0092] Rate backoff factor: The symbol transmission rate differs from the symbol rate given by the bandwidth. Typically, in high-bandwidth systems, the symbol transmission rate is less than the symbol rate given by the bandwidth to avoid ISI.

[0093] Objective: Within the CIR, or in other words, within the assumed symbol duration T of the OFDM system. (SY) Internal transmission of two symbols → corresponds to a rate backoff factor of 1 / 2.

[0094] Related to this, Figure 4a This illustrates multi-user media access control in a multi-user (MU) - single-input multiple-output (SIMO) configuration, while Figure 4b The MU-MIMO MAC (Media Access Control) is shown. Furthermore, Figure 5aThis illustrates a multi-user broadcast channel in MU-MISO (Multiple-Input Single-Output) broadcasting, while Figure 5b This demonstrates MU-MIMO broadcasting.

[0095] also, Figure 6a An example plot is shown, illustrating the relative power on the vertical axis over a delay in μs to plot the line-of-sight (LOS) with the original CIR. Figure 6b The LOS equivalent CIR with TR (time reversal) precoding is shown. Figure 6c The corresponding non-LOS (NLOS) equivalent CIR with TR precoding is shown, while Figure 6d The NLOS equivalent CIR with TR is shown. Figure 6e A schematic diagram of the CIR obtained in the example office is shown, in which Figure 6f The taps of the pre-equalized channel are shown.

[0096] According to an embodiment, the pre-encoder unit 312 is configured to obtain channel information related to the multipath propagation of a signal from the device to the receiver. The pre-encoder unit 312 and the device 302 can each be configured to select a corresponding set of paths from the multipath propagation. For example, this multipath propagation can be derived from the reference signal (RS) of the device 302 itself or from feedback from other communication links (base stations) that report channel state information (CSI) to the device 302. That is, the device 302 can determine the corresponding information itself, or it can receive information already determined at a communication partner.

[0097] According to an embodiment, interface 308 can be configured to form at least one beam from a set of beams using beamforming technology. Device 302 can be configured to transmit both precoded signal 3221 and precoded signal 3222 using a single beam from the beam set or a subset of the beam set. Using a beam set can be achieved by using a superimposed beam of two beams belonging to that set. Essentially, the transmitted radiation characteristics can be understood as beams or combinations of beams forming new, combined, or superimposed beams. That is, a single beam can be a single beam or a superposition of beams.

[0098] According to the embodiments and as follows Figure 3b As shown, the pre-encoder unit 312 may include two or more branches 3361, 3362, each branch 336 configured to obtain corresponding data signals 3141, 3142 and to generate corresponding pre-encoded signals 3221, 3222' / 3222. At least one path 336 may include a corresponding offset unit 326. According to an embodiment, the offset units in different branches 336 may provide different delays for the signals. For example, the offset unit 326 may be implemented as a delay filter.

[0099] The time / frequency difference between precoded signals 3221 and 3222, performed by offset unit 326 for the undelayed / unoffset version or the less delayed / offset version, can be set based on different considerations. Considering a time delay, the delay could be at most the maximum channel delay between device 302 and receiver 304. Alternatively, the delay could be set to the duration of at most the symbols of the precoded signals 3221 and / or 3222, where the symbol duration may be longer than the channel delay.

[0100] The delay of the precoded signal 3222 relative to the precoded signal 3221 can be at most the symbol sampling rate at receiver 304. The context for choosing this delay is that the receiver samples the received signal at a specific sampling rate / bandwidth, and the effective signal representation in the digital time domain after analog-to-digital conversion (ADC) may or should allow the creation of a digital time delay structure. In principle, this delay structure could also be implemented in the analog domain; however, the determination of the delay and value of the signal combination can generally be performed in the digital domain. The value of the symbol sampling rate at receiver 304 can be known at device 302.

[0101] The embodiments involve a scenario where, with more than one receiving antenna and the antenna spacing exceeds its narrowband coherence distance, the receiver can distinguish multiple streams by creating spatial characteristics of an effective MIMO channel, just as a transmitter can transmit different streams from different antennas with different beams simply by using the delay precoding technique described in this disclosure. Narrowband coherence distance refers to the wavelength at which the physical antenna spacing (wrt) causes the phase difference to be below a certain threshold.

[0102] In conjunction with application scenario 1.), device 302 can be configured to generate signals 332 and 3222 respectively, such that the bandwidth occupied by the signals is lower than the achievable or permissible conceivable bandwidth. Alternatively or additionally, receiver 304 can be configured to sample the received combined data signals to parse the transmitted signals 3221 and 3222 to obtain a corresponding data stream with a signal bandwidth lower than the achievable signal bandwidth. For example, the described high-resolution delay precoding can be implemented at a medium system bandwidth, such as 100 MHz or below.

[0103] In application scenario 4.)a.), a "tap" can be understood as the concentration of different signal taps within a time delay window. The signal does not necessarily need to perfectly match the channel delay and form a single tap almost entirely surrounded by nearby echo attenuation, such as... Figure 7 As shown.

[0104] Implementation examples may involve time delay / Doppler (DD) pre-encoder designs.

[0105] The design of delay / Doppler pre-encoders (DDPs) can follow the following standards:

[0106] Spatially multiplexed data streams should be pre-encoded so that they are efficiently mapped to:

[0107] - Specific delay clusters in the propagation environment (delay clusters are paths with similar delay lengths given a time window) or / and

[0108] - Selected multipath component (MPC) with significant power visible in the power delay / Doppler profile, and / or

[0109] - Selected taps with appropriate (time) distances between each other fully separate all "non-DD matched" power components from the target received signal window where the useful power should be concentrated.

[0110] The following paragraphs present some potential implementations of the time-delay precoder to provide practical insights into the feasibility of the proposed technique. Examples of delay component implementations are described in detail, exemplarily. Similarly, the same mechanism can be applied to Doppler component implementations caused by the relative motion of the transmitter, receiver, or reflecting object in the propagation environment, resulting in a carrier frequency shift and thus energy spillover from the OFDM subcarrier to adjacent subcarriers. By applying path-specific Doppler compensation, the signal at the receiver is effectively perceived as Doppler-free or at least with reduced Doppler spread.

[0111] Example 1: Precoder design with a single transmit antenna and a single receive antenna

[0112] Consider a broadband wireless communication system with a transmitter (Tx) and a receiver (Rx), such as Figure 3b As shown in the diagram. Tx and Rx are each equipped with a single antenna. In Tx, the data stream X1 = [x 11 ,x 12 ,…,x 1N ] T It is passed to the precoder to transmit via the wireless broadband channel h = [h1, h2, ..., h L ] T Transmission is performed, where h is a channel vector with L channel taps. The second data stream X2 = [x 21 ,x 22 ,…,x 2N ] T It is processed in the same way as the first data stream, but its pre-coded output signal is delayed for a certain period of time before transmission.

[0113] We assume the system bandwidth is wide enough to handle many wireless multipath components. Applying the precoder described above results in the effective channel in the system having most of the energy concentrated near the main peak / tap as observed from the receiver side, and the remaining energy components in the delay window are significantly reduced by extending them into the time domain. In other words, if the channel is described by a tapped delay line model, the effective channel after applying the precoder will result in a main tap with a certain delay having much higher power than the other taps. In such a system, the precoder can be designed as a matched filter similar to the channel impulse response (a time-reversed and phase-conjugate version of the channel impulse response), i.e. The effective channel is then derived through convolution of the channel impulse response and the precoder, i.e. Where g is an effective channel with a maximum tap power of g1. An example of a generated effective channel is shown below. Figure 7 As shown in the figure, the main tap has a power that is about 15 dB higher than the other taps.

[0114] Note that under high SNR conditions, it is desirable to transmit two or more data streams instead of a single data stream to achieve higher system throughput for a given total transmission power across all data streams. In this case, the scheme described above enables us to transmit two data streams, each with half the transmission power, to achieve higher throughput than a traditional single-stream transmission scheme.

[0115] Figure 7 This is an example of an effective channel after applying a matched filter to the channel impulse response, as shown in [EKPP10]. Figure 3b In this design, the second data stream (X2) is delayed relative to the first data stream by a certain duration. This delay is also a design parameter, and it plays a significant role in... Figure 3b This is described as a functional block. Typically, the delay can be chosen, for example, less than the sampling duration, such that the peak power of the effective channel experienced by the second data stream occurs less than one sampling duration later than the first data stream. For example, this is in... Figure 8 The diagram shows an example where, for simplicity, the delay is assumed to be half the sampling duration. Let g1 q denote the highest power tap g1 of the q-th data stream. The signal received over two consecutive half-sampling durations can be written as:

[0116]

[0117] Where y = [y1, y2] T and n = [n1, n2] T These represent the received signal and noise for two consecutive half-sampling durations, respectively; g I1 and g I2These are the effective channel coefficients of the first and second data streams that cause inter-symbol interference, as shown in the figure. Therefore, given the received signal y (signal 332 after passing through the channel) and the estimated channel tap, the data stream x can be directly detected using a conventional MMSE (Minimum Mean Square Error) receiver. 11 and x 21 .

[0118] In other words, device 302 can be configured to transmit precoded signals 3221 and 3222 as a superposition of precoded signals in the time domain. That is, at least a portion of the corresponding precoded signals 3221 and 3222 can be transmitted at the same time, which is different from transmitting different precoded signals in different time slots, time intervals, etc.

[0119] The embodiments can also involve a single transmitting antenna and a single receiving antenna, in addition to a single transmitting antenna and a single receiving antenna. Extending this to multiple receiving antennas is straightforward. For simplicity, we assume two receiving antennas. Following the notation in Example 1, let the superscript (n) denote the nth receiving antenna. The signals received by the two receiving antennas over two sampling durations can be written as...

[0120]

[0121] Given the received signal and the estimated channel taps, the transmitted data stream can be estimated using a conventional MMSE receiver.

[0122] According to an embodiment, the pre-encoder unit is configured to apply windowing to pre-encode data signals 3141 and / or 3142. This can allow for reduced computational complexity by limiting the pre-encoded signals 3221 and / or 3222 to taps or power portions, which include, for example... Figure 9 As shown, a large amount of energy is filtered while other portions, including energy levels below a threshold, are filtered.

[0123] In other words, the example involves a precoder design using windowing. In Example 1, the precoder is designed as a matched filter of the channel impulse response. If the channel impulse response is very long, the computational complexity of the precoder becomes very high. To reduce complexity, windowing can be applied to taps with power above a certain threshold, such as... Figure 9 As shown in the diagram. A precoder is then designed to match the channel taps that survive windowing. This enhances high-power taps and suppresses taps outside the window.

[0124] Example 4: Precoder design using a channel shortening filter

[0125] The goal of a channel shortening filter is to compress channel energy into a short duration of L samples. In other words, it generates an effective channel, i.e., a cascade of the channel and the channel shortening filter, which compresses most of the energy into fewer adjacent taps. The performance metric of a channel shortening filter can be designed as the ratio of channel energy within a shortened window of length L samples to channel energy outside this window, called the shortened SNR (SSNR).

[0126] The energy of an effective channel can be divided into two parts: signal energy and interference energy. The signal energy component is the energy of the channel within the target's shortened window. The interference energy is the energy of the channel outside the target's shortened window. Let g = [g Δ ,g Δ+1 ,…g L ] T Indicates an effective channel. The signal energy component g of the channel. win Interference energy component g of the channel wall Can be written as

[0127] g win =g(Δ,Δ+1,...,L) s )

[0128] and

[0129] g wall =g(L s+1 ,...,L),

[0130] Where Δ is the equalization delay. The output SSNR of the effective channel response can be written as:

[0131]

[0132] The SSNR-maximizing filter can be solved using the generalized eigenvalue solution given by [MYR96][CE10].

[0133]

[0134] Examples of raw and shortened channel impulse responses (effective channel) are as follows: Figure 10 As shown, the original channel impulse response and the shortened channel impulse response.

[0135] In addition to reporting on channel information and / or multipath components, embodiments may involve signaling between transmitter 302 and receiver 304. For example, one entity may determine that the channel is good enough (e.g., the SNR is above a certain threshold, such as 10 dB), and one or more additional signals may be combined. Figure 3a and Figure 3bThe described delay / Doppler precoding is used for transmission. For example, the device can be configured to transmit capability information indicating that device 302 is configured to transmit at least two precoded signals with the same transmission radiation characteristics of wireless interface 308. For example, such capability information may be a partial CIR report. Device 302 can be configured to transmit capability information to include information relating to at least one of the device's location, scenario, and mobile cluster. Alternatively or additionally, device 302 can be configured to receive capability information indicating that a receiver is capable of decoding combinations of precoded signals 3221, 3222 and possible additional precoded signals. Device 302 can be configured to select to either transmit a combination of precoded signals or not based on capability information. That is, device 302 can implement the described precoding if the device is notified to the receiver that it can simultaneously decode precoded signals (within the applied delay) and if the channel includes quality at least a quality threshold. Alternatively or additionally, device 302 can directly or indirectly notify receiver 304 that it is capable of performing the described precoding. Device 302 can implement the described precoding upon request or with some permission. When a request message indicating that the device is requested to send a precoded signal 322 is received, the device can be configured to operate according to the request. The request message can be generated by the receiver 304 and / or different nodes, such as a network coordinator.

[0136] The device can be configured to acquire channel information. The channel information may include channel state information (CSI), which indicates, for example, the existence of one or more multipath components (MPCs) between the device and the receiver. The channel information may include channel quality information, such as information related to each or at least a portion of the channel identified by the channel state information. The channel information may indicate the channel quality between the device and the receiver. The channel information may indicate that the channel quality is above a channel quality threshold. The device can be configured to transmit precoded signals 3221, 3222 and optionally additional combinations of precoded signals, having the same transmit radiation characteristics of the wireless interface 308 based on the channel quality information. Therefore, the CSI may be sufficient or helpful in determining whether two streams mapped to the MPC can be successfully transmitted.

[0137] Reference again Figure 8Simultaneously, two or even more precoded signals can be transmitted, with corresponding, preferably explicitly defined, delays applied to other precoded signals. For example, a third precoded signal based on a third path between the device and the receiver may include a time offset, i.e., a delay, which differs from the delay applied in offset unit 326. In the combined signal, therefore, the corresponding components based on the precoded signals may also be delayed relative to each other. Device 302 can be configured to transmit delay information indicating the time delay of at least the symbols between precoded signals 3221 and 3222, i.e., information representing the delay Δt of the application implemented by offset unit 326.

[0138] Delay information, such as τ 1,2 This allows the receiver to be instructed on where to search for or detect peaks in the signal, thereby enhancing decoding. Such enhancements are particularly advantageous in scenarios with high loads or traffic in channels that may experience significant interference, especially in unlicensed frequency bands.

[0139] Device 302 may include a single transmit antenna, a single transmit array, or a single active antenna or antenna port for transmitting wireless signals in a multiplexing node. That is, even though it includes only a single antenna, device 302 can still be configured to perform multiple-input multiple-output communication mode / spatial data stream multiplexing.

[0140] In other words, the implementation involves the necessary conditions for signaling notification:

[0141] 1. Channel impulse response (CIR), preferably with high resolution in the time (delay) domain, must be obtained and available at the transmitter side.

[0142] This can be obtained from previously transmitted pilot signals, such as in 5G NR, which could be SRS in the uplink or CSI-RS in the downlink or DM-RS in either the uplink or downlink direction.

[0143] In 5G NR or other systems, the channel may be estimated in the frequency domain, such as the complex coefficients of each OFDM subcarrier, and the channel impulse response may be obtained by transforming to the time domain, such as by FFT / DFT.

[0144] The uplink / downlink pilots should be configured to cover as much bandwidth as possible, as higher bandwidth will increase the estimated CIR time / delay resolution.

[0145] The receiver needs to report the CIR or the transmitter needs to estimate the CIR using channel properties, such as channel reciprocity or any other reconstruction, such as detection of the main scatterer or second-order statistics, as well as additional signal processing or prior knowledge in the CIR, such as fixed wireless access or backhaul.

[0146] CIR reports can be compressed in a lossless or lossy manner, such as using codebooks for different channel components (time, space, delay, Doppler, frequency).

[0147] 2. Delayed multiplexing capability – RX and / or TX can notify each other whether they have delayed multiplexing capability.

[0148] This information requires new signaling. This can be communicated via new metrics, such as new UE capabilities, or indirectly, such as by testing or monitoring UE performance.

[0149] Optimized CIR Report

[0150] CIR reports (e.g., via delayed Doppler representation) can be optimized by classifying UEs into aligned location, scene, and mobility clusters to reduce the range of values ​​in the CIR. This can be used to improve resolution with fixed quantization ranges (offset, bit range, bit width) or to reduce report size without losing important information.

[0151] ● Classification can be performed by the transmitter based on prior or supplementary information. The transmitter must notify the receiver.

[0152] ● Classification can be performed at the receiver side: a larger, more complete range can be recorded and compressed using appropriate categories (e.g., selecting the appropriate quadrant). The receiver must signal the category being used.

[0153] ●Dynamically adjust the range. This can be determined by the transmitter or by the receiver adaptively transmitting signals.

[0154] Information requested at Rx

[0155] In order to successfully perform symbol detection at the receiver, the following additional information is required compared to traditional systems such as LTE / 5G:

[0156] 1. Number of delay-multiplexed symbols / layers

[0157] o Implement new signaling for this information

[0158] This can be an N-bit value. Some examples are listed below:

[0159] ● The maximum delay precoding uses two symbols. Using this single bit is sufficient to indicate whether one symbol (traditional) or two symbols (proposed) are transmitted.

[0160] ● The maximum delay precoding symbol count is 4 or 2. N Then 2 bits or N bits are needed respectively.

[0161] o may have the following options:

[0162] ● The receiver decides, for example, based on a high received SNR or suitable CIR conditions, to increase throughput by using the proposed scheme and signals to the transmitter that two or more symbols should use the proposed scheme for delay precoding. For example, the BS is the receiver and the UE is the transmitter. (Short version: Network Control)

[0163] ●BS is configured to generate CIR measurement reports, which are triggered when the CIR meets certain criteria at the receiver, such as: applicable to TDMux, significant scattering, short pulse response, high Doppler spread, etc.

[0164] ● The transmitter, such as the UE, can make its own decisions based on a metric, such as channel quality measurement, i.e., using a proposed scheme to perform delay precoding on two or more symbols, for example, the BS is the transmitter and the UE is the receiver, or vice versa. This can be controlled by the network or the UE. In the case where the UE is the transmitter, the network usually makes the decision.

[0165] At the same time, this signal can be used to indicate whether the proposed solution is applied. For example, to reduce complexity, an additional field can be used to indicate that this is a direct extension.

[0166] 2. Timing of Peak / Tap / Tap Clusters – An example using symbols with 2 delay pre-coded symbols, where the delay / interval between the first peak corresponding to symbol 1 and the second peak corresponding to symbol 2 is τ. 1,2 This indicates that it is optional in the following sense. Without this signaling, the receiver detects the two highest peaks and separates them through appropriate signal processing for channel equalization and decoding. Using the additional signaling described below, additional lateral constraints are imposed, such as the second peak must be added to the first peak by τ. 1,2 Within a certain threshold. Therefore, this feedback increases the probability of successful decoding by the receiver.

[0167] o Implement new signaling for this information

[0168] oτ 1,2 It can be directly signaled as a value, for example in microseconds or nanoseconds, or indirectly, for example, in multiples of the symbol duration, or via an index from a predefined time grid.

[0169] According to an embodiment, a device such as receiver 304 may be configured to obtain capability information indicating a plurality of precoded symbols of a data signal transmitted by a transmitter. For example, the capability information may indicate the maximum number of precoded symbols of different data signals currently or potentially transmitted by the transmitter using the described precoding, such as symbols of delay and / or frequency shift. Device 304 may include a wireless interface configured to receive wireless signals, such as an antenna and / or panel, combinations thereof, etc. Device 304 may include a decoder unit configured to sample the combined data signal, such as signal 332 already transmitted through channel 332, to obtain a sampled representation of the combined data signal. The decoder unit may be configured to identify a number of offset symbols in the sampled representation, for example, by detecting the combined... Figure 8 The number of offset signals can be based on capability information. That is, the receiver can include information indicating the number of peaks it must search for and / or information expecting these peaks in time and / or frequency. The decoder unit can be configured to separate multiple offset data signals based on the combined data signal 332 to obtain at least a first data stream and a second data stream. That is, the decoder can decode the signal based on capability information.

[0170] Device 304 can be configured to determine quality information that indicates to the transmitter, for example, that the channel quality of device 302 is above a quality threshold. Device 304 can also be configured to send a request or command to a transmitter of a wireless signal to transmit symbols of another signal as multiple time-delayed versions of the symbols.

[0171] Further embodiments relate to wireless communication networks, such as network 300, in which one or more of devices 302 may be arranged. Additionally, one or more devices 304 may be arranged. Optionally, receiver 304 may be implemented to operate based on capability information.

[0172] The embodiments described herein relate to precoded signals with multiple time delays transmitted by a transmitter using the same transmit radiation characteristics. As described, this can allow for increased throughput on the channel.

[0173] The further embodiments described herein allow for low requirements on the receiver, such as device 304. Alternatively, or in addition to time delaying the precoded signal at the transmitter, the network can be operated such that the transmission of signals from different devices or different antenna panels is scheduled to be combined with... Figure 8The described similar approach arrives asynchronously. That is, precoded signals are not generated at the same device; different devices can provide such signals. For such a proposal, the wireless communication network may include a coordinator configured to coordinate the first and second devices, such that the first and second devices transmit their signals so that they arrive at the receiver with a time delay relative to each other. The receiver may be configured to receive different signals having the same antenna reception characteristics, i.e., having the same receive beam or antenna configuration. This can be understood as receiving signals of the same spatial resolution.

[0174] The coordinating device can be executed individually or in groups, thereby controlling the group to achieve group-specific time delays for its signals. Through such control, in response to instructions received directly or indirectly from the coordinator, the device can deviate from the timing of signal transmission, such that signal arrival includes an offset relative to the synchronization schedule. Therefore, the device can deviate from frequency correction by applying Doppler domain bias.

[0175] Alternatively or additionally, the coordinator can be configured to coordinate the first and second devices with respect to time delay and time anchor. This mechanism may include a so-called delay spread parameter, which may describe an spread and / or delay instance of the channel impulse response at the target receiver, e.g., between the centers of the main delay taps or near the main power concentration in the time domain, and / or delay tap advance, e.g., once a delay spread is achieved through precoding of a single user / equipment, delay tap advance will allow one receiver delay to be offset relative to another by instructing the devices to do so. For example, a device may be instructed to apply a specific time delay, but may deviate from this instruction by one or more parameters within a specific interval, e.g., slightly increasing or decreasing the time delay. The coordinator unit, which may be arranged as part of a base station but may also be different and, in particular, a separate entity, may be configured to provide the first and / or second devices with information relating to a target value of the parameter indicating the delay to be applied. The first and / or second devices may be adapted to operate according to the target value.

[0176] Such operations, which relate to deviations from synchronization behavior in communication, can be implemented alternatively or by adding to the precoding of multiple signals described at the same device.

[0177] In other words, in the uplink, two or more users can perform precoding on the transmitted signals so that the signals received at the base station can be distinguished by delay, thereby allowing for differentiation between users with a very simple receiver architecture. This can enhance communication if the spatial resolution at the receiver is insufficient, for example, if the beam used by the receiver does not allow two or more users to be spatially separated. Embodiments involve precoding, for example, in a delay domain performed across an individual or a group of users. Embodiments also involve allowing the user set and the base station to jointly determine delay control with respect to a time anchor, such as a specific absolute or relative time, and / or Doppler control relative to a frequency anchor relative to the offset in the Doppler domain, such as a specific frequency. In conjunction with the above description, target values / KPIs (Key Performance Indicators) such as effective signal spread can be used as feedback parameters in the standard; for example, 80% (or other suitable value) of the total received signal power from a device (UE) or MIMO layer transmitting from one or more UEs should be within a specific layout spread. Alternatively or additionally, other parameters may be used.

[0178] • A high system SINR at receiver k is denoted as γ k Above the threshold γ (tr) , making γ k >γ (tr) For example, γ (tr) =10dB, at a given transmission bandwidth, switching to spatial multiplexing instead of increasing modulation and coding schemes becomes advantageous in terms of spectral efficiency.

[0179] ● In order to separate the data streams transmitted simultaneously using radio, the rank (spatial degrees of freedom) of the effective channel must be >1. This is usually achieved by multiple Tx and multiple Rx antennas. This is effective even in narrowband channels if the antennas are sufficiently separated, taking advantage of rich multipaths and the superposition of signals with random phase and amplitude at the receiving antenna.

[0180] ● Due to the wide bandwidth of the transmitted broadband signal and the resulting high time resolution, paths and / or groups of paths can be resolved in the time domain or the delay domain.

[0181] ● We propose a concept for transmitting filter design that matches the delay structure of the correlated path groups connecting Tx and Rx positions, thereby mapping different data streams onto these separable multipath components (MPCs) at the receiver side.

[0182] ● This method allows spatial multiplexing to be utilized using only a single transmitter antenna. The aim is to increase the physical layer's transmission throughput, meaning the total rate of spatially multiplexed transmissions should be greater than the rate of single-stream transmissions. This decision can be based on measured single-stream SNR or SINR, or a reference signal such as CSI-RS, SRS, or other measurement reports such as RSRP. It can also be based on predicted SINR or the total rate of multiplexed transmissions, or the spatial structure of the channel, such as through the structure of delay components.

[0183] ●→Related, such as UE UL in FR2

[0184] 1. The embodiment has the following advantages: a transmitter with a single transmit antenna can create MIMO-like spatial characteristics without the need for multiple transmit antennas required by a state-of-the-art MIMO transmission scheme.

[0185] 2. The proposed scheme can be applied to radio transmission systems with wide system bandwidths, such as Nx 100MHz or several GHz, as well as systems with narrower bandwidths but operating WRT signal generation, allowing for a much higher transmitter sampling rate, but at least a Nyquist sampling rate, to separate the path input in the time domain. For example, a 20MHz wide transmit signal can be created using a sampling rate of 100 or 400MHz, which is equivalent to an oversampling rate of 5 or 20 times, allowing for better channel matching in delay precoding compared to the minimum time resolution required for sampling a 20MHz signal at the Nyquist rate. That is, the device can be configured to generate a transmit signal with an effective signal bandwidth lower than the achievable signal bandwidth at a given sampling rate supported by the digital-to-analog converter of the precoder unit. At the transmitter, a higher sampling rate than actually required to satisfy the Nyquist criterion for a specific bandwidth can be used to better match the precoding filter with the channel impulse response in the time domain. At the receiver, a higher sampling rate than Nyquist can be used to better resolve the MPC, which forms a portion of the effective channel impulse response after precoding and is transmitted via the wireless channel.

[0186] 3. The proposed solution will allow for spatial reuse without requiring multiple transmit antennas or multiple beams to be formed simultaneously by one or more antenna arrays.

[0187] 4. Single-beam / single-antenna transmitters can increase throughput simply by using the proposed multiplexing method, without the need for additional hardware such as transceiver chains.

[0188] 5. The proposed method can be used on existing UEs by implementing a delay / Doppler precoder with a suitable transmitter sampling rate.

[0189] While the embodiments described herein relate to wireless devices such as device 302 communicating with receivers such as device 304, the embodiments are not limited to point-to-point communication as indicated by a coordination group, whereby the group is controlled to implement packet time delay / Doppler offset of its signals. Alternatively or additionally, and as described below, transceivers or devices may precode signals to address two or more receivers in an uplink scenario. Optionally, the two receivers may perform joint processing on the received signals. Alternatively or additionally, receivers may receive precoded signals from different transmitters. For example, different transmitters may be coordinated to address two or more receivers.

[0190] Figure 12a A schematic block diagram of at least a portion of a communication network 12001 is shown, in which device 302 precodes signals 3221 and 3222 according to channel conditions or path groups to different receivers 3041 and 3042. According to an embodiment, device 302 can precode more than two signals. For example, a third precoded signal can be precoded to receiver 3041 or 3042 according to channel conditions, or according to channel conditions between device 302 and another receiver (not shown). As explained, device 302 can implement different, possibly separate, sets of multipath components to obtain precoded signals 3221 and 3222, and then transmit them jointly.

[0191] Optionally, receivers 3041 and 3042 can exchange copies of the signals they receive by exchanging signal 344. Signal 344 may include or enable one or more of the following:

[0192] a. Exchange of decoding results

[0193] b. Exchange of intermediate signal processing results, such as I / Q values, soft bits, and preprocessed received signals.

[0194] c. Forward all received signals, such as those from a distributed antenna system (DAS), to the central baseband processing unit.

[0195] d. Local processing of the streams / data that each receiver and exchange intends to receive / process can be at least part of auxiliary information to help other base stations decode their intended messages—such as auxiliary feedback. For example, this could be a guess about messages sent to other BSs or sharing correctly decoded messages so that other BSs can better eliminate interference from messages sent to another BS / receiver through successive interference cancellation (SIC).

[0196] The embodiments can also operate without swaps, but can be enhanced by swaps to allow joint detection.

[0197] That is, receiver 3041 can send a copy of the signal it receives to receiver 3042 and / or receiver 3042 can send a copy of the signal it receives to receiver 3041. This can allow for enhanced decoding of the signal.

[0198] In other words, the embodiments involve multiplexing from one UE to several BSs in an uplink UL, dual connectivity (DC), or multiple connectivity (MC). Precoding can be performed based on the channel impulse response between UE 302 and BS1 (3041) and between UE 302 and BS2 (3042). In particular, a specific precoding, such as delay precoding, must be matched to the channel associated with the target BS, while it should be offset relative to other base stations so that the received signals at the BS receiver are well separated in, for example, the delay domain. Since the signals received at other BSs are not concentrated in, for example, the delay domain, and due to the different delay spread and tap (MPC) numbers and tap positions between the UE and other BSs, the precoded data of the other BSs will be spread in the delay domain, and the choice of delay difference / offset can be determined such that the received power concentration in, for example, the delay domain of another stream is significantly offset, or, if possible, offset to the maximum distance. The terms “maximum” and “quite large” may be influenced at least by the channel impulse response structure, which may be very different or very similar between UE and BS1 and between UE and BS2.

[0199] Furthermore, the embodiments involve joint processing at two or more BSs in the uplink, such that when the precoding of the two (or more) streams 3221 and 3222 is completed, the streams can be separated via independent paths at multiple BSs through MIMO processing in the delay domain reception.

[0200] Figure 12b A schematic block diagram of at least a portion of a communication network 12002 is shown, in which two or more devices 3021 and 3022 act as transmitters of signals, and a receiver 304 receives both signals. This implements a scenario similar to a downlink. Transmitters 3021 and 3022 can operate as a virtual single transmitter based on synchronization or coordination provided, for example, by a coordinating node 342. The coordinating node can allow both devices 3021 and 3022 to obtain the requested information and operate in a coordinated manner, synchronously or in unison. This may involve or imply joint processing where timing can be closely synchronized, coarsely synchronized, loosely synchronized, or not synchronized at all (in time and / or frequency) but still coordinated. However, synchronization can be handled individually or jointly in the time / delay and / or frequency / Doppler domain.

[0201] In other words, with Figure 12aIn the same uplink scenario, two or more BSs can precode their signals to the same UE, thereby enabling the use of delay domains and different strip delay line filters to separate the superposition of streams.

[0202] Figure 12c A schematic block diagram of at least a portion of the communication network 12003 is shown, wherein Figure 12a and Figure 12b The embodiments are combined by implementing synchronous (tightly synchronized, coarsely synchronized, loosely synchronized, or not synchronized at all) transmitters 3021 and 3022 and more than one receiver 3041 and 3042, wherein receivers 3041 and 3042 can receive signals from each of devices 3021 and 3022 respectively. On the one hand, those signals 322 of device 3021... 11 and 322 12 And on the other hand, signal 322 21 and 322 22 It can be pre-encoded to include the offset in the delay / Doppler domain. Devices 3041 and 3042 and / or devices 3021 and 3022 can exchange signals 3441 and / or 3442 with respect to their respective received signals, as in combination. Figure 12a The concept of network 12003 can be implemented alternatively or additionally in the communication direction from devices 3041 and / or 3042 to devices 3021 and / or 3022. The selection of the path set can be chosen to anticipate low or even minimal interference between different precoded signals.

[0203] Although in the described embodiments, such as Figure 12a In the embodiments described in -c, some devices are illustrated as having one antenna, while others are illustrated as having two antennas, but the embodiments are not limited to the number of antennas shown. Each device may include a single or group (for a group of devices) number of antennas, antenna elements, antenna arrangements, antenna panels, etc. That is, all transmitters and all receivers can operate using one or more transmit and / or receive antennas.

[0204] In other words, in the case of multiple UEs, two BSs are respectively (one BS is transmitting to one UE, i.e.) Figure 3aMultiple instances of the signal (or joint transmission between two BSs preparing signals to be transmitted to two UEs) precode the signal for each UE. If this is done fully or adequately, it is almost equivalent to CoMP joint transmission in DL. In the context of the described embodiments, the jointly or individually precoded signals, for example in the delay domain, should only match a portion of the MPC provided by the channel impulse response between the transmit antenna and the intended receive antenna, and combined with the delay offset between the two streams, such that the power received by the UE receiver is offset from each other and spread to allow for efficient signal separation.

[0205] The selection of multipath components for precoding can be based on considerations of interference. For example, different path groups can be selected so that signals 3221 and 3222 cause low or minimal interference to each other.

[0206] Note that although receiver or device 304 is indicated as a base station, device 304 can be any other device capable of performing multipath communication, such as a user equipment, base station, or repeater. Note that although device 302 is indicated as a UE, device 302 can be any other device capable of performing multipath communication, such as a user equipment, base station, or repeater. Devices 302 and / or 304 can be fixed, but can also be mobile entities in terrestrial or non-terrestrial networks.

[0207] The embodiments of the present invention have been described in detail above. Each embodiment and aspect can be implemented individually or in combination of two or more embodiments or aspects.

[0208] The above embodiments relating to various aspects of the invention are described in an environment where communication takes place between a transmitter, such as a gNB or UE, and a receiver, such as a UE and a gNB. However, the invention is not limited to this type of communication; rather, the above principles can also be applied to device-to-device communication, such as D2D, V2V, and V2X communication. In this scenario, communication is conducted via a sidelink between the devices. The transmitter is a first UE, and the receiver is a second UE communicating using sidelink resources.

[0209] According to embodiments, a wireless communication system may include a terrestrial network or a non-terrestrial network, or a network or network segment that uses aircraft or space vehicles or combinations thereof as receivers.

[0210] According to embodiments, the User Equipment (UE) can be a mobile terminal, a fixed terminal, a cellular IoT-UE, a vehicle-mounted UE, a vehicle-mounted group leader (GL) UE, an IoT device, a narrowband IoT device, an NB-IoT device, a WiFi non-access point station, a non-AP STA (e.g., 802.11ax or 802.11be), a ground-based vehicle, an aircraft, a drone, a mobile base station, a roadside unit, a building, or any other item or device with network connectivity that enables the item / device to communicate using a wireless communication network, such as a sensor or actuator, and / or a base station (BS), which can be implemented as a mobile or non-mobile base station, and can be a macro cell base station, a small cell base station, a central unit of a base station, a distributed unit of a base station, a roadside unit, a UE, a group leader (GL), a relay, a remote radio head, an AMF (Agency Foundry), an SMF (Small Medium Foundry), a core network entity, a mobile edge computing entity, a network slice in the NR or 5G core context, or a WiFi AP. STA, such as 802.11ax, 802.11ad / ay, or 802.11be, or any one or more of the Transmitter / Receiver Points (TRPs) that enable an article or device to communicate using a wireless communication network, the article or device having network connectivity to communicate using a wireless communication network.

[0211] Although certain aspects of the described concepts have been described in the context of the apparatus, these aspects clearly also represent a description of the corresponding method, where a block or device corresponds to a method step or a feature of a method step. Similarly, aspects described in the context of a method step also represent a description of a corresponding block, item, or feature of the corresponding apparatus.

[0212] The various elements and features of this invention can be implemented in hardware using analog and / or digital circuitry, in software by instructions executed by one or more general-purpose or special-purpose processors, or as a combination of hardware and software. For example, embodiments of this invention can be implemented in the environment of a computer system or another processing system. Figure 11An example of a computer system 500 is shown. Units or modules, and the steps of methods performed by these units, can be executed on one or more computer systems 500. The computer system 500 includes one or more processors 502, such as dedicated or general-purpose digital signal processors. The processors 502 are connected to a communication infrastructure 504, such as a bus or network. The computer system 500 includes a main memory 506, such as random access memory (RAM), and an auxiliary memory 508, such as a hard disk drive and / or a removable storage drive. The auxiliary memory 508 may allow computer programs or other instructions to be loaded into the computer system 500. The computer system 500 may further include a communication interface 510 to allow software and data to be transferred between the computer system 500 and external devices. Communication can be electronic, electromagnetic, optical, or other forms of signals that can be processed by the communication interface. Communication can use wires or cables, optical fibers, telephone lines, cellular telephone links, RF links, and other communication channels 512.

[0213] The terms "computer program medium" and "computer-readable medium" are generally used to refer to tangible storage media, such as removable storage units or hard disks installed in hard disk drives. These computer program products are means for providing software to computer system 500. The computer program, also known as computer control logic, is stored in main memory 506 and / or auxiliary memory 508. The computer program may also be received via communication interface 510. When executed, the computer program enables computer system 500 to implement the present invention. In particular, when executed, the computer program enables processor 502 to implement the processes of the present invention, such as any methods described herein. Therefore, such a computer program can represent a controller of computer system 500. When implementing this disclosure using software, the software can be stored in a computer program product and loaded into computer system 500 using a removable storage drive, an interface such as communication interface 510, etc.

[0214] The hardware or software implementation can be executed using digital storage media, such as cloud storage, floppy disks, DVDs, Blu-rays, CDs, ROMs, PROMs, EPROMs, EEPROMs, or FLASH memories, which store electronically readable control signals that cooperate (or are capable of cooperating with) a programmable computer system to execute corresponding methods. Therefore, digital storage media can be computer-readable.

[0215] Some embodiments of the invention include a data carrier having electronically readable control signals, which is capable of cooperating with a programmable computer system to perform one of the methods described herein.

[0216] Typically, embodiments of the present invention can be implemented as a computer program product having program code that, when run on a computer, is operable to perform one of the methods. The program code may, for example, be stored on a machine-readable medium.

[0217] Other embodiments include a computer program stored on a machine-readable medium for performing one of the methods described herein. In other words, embodiments of the methods of the present invention are therefore computer programs having program code for performing one of the methods described herein when the computer program is run on a computer.

[0218] Therefore, a further embodiment of the method of the present invention is a data carrier (or digital storage medium, or computer-readable medium) having a computer program recorded thereon for performing one of the methods described herein. Therefore, a further embodiment of the method of the present invention is a data stream or signal sequence representing a computer program for performing one of the methods described herein. The data stream or signal sequence may, for example, be configured to be transmitted via a data communication connection, such as via the Internet. Further embodiments include processing means, such as a computer or programmable logic device, configured or adapted to perform one of the methods described herein. Further embodiments include a computer having a computer program mounted thereon for performing one of the methods described herein.

[0219] In some embodiments, a programmable logic device (e.g., a field-programmable gate array) may be used to perform some or all of the functions of the methods described herein. In some embodiments, the field-programmable gate array may cooperate with a microprocessor to perform one of the methods described herein. Generally, these methods are preferably performed by any hardware device.

[0220] The above embodiments are merely illustrative of the principles of the present invention. It should be understood that modifications and variations to the arrangements and details described herein will be apparent to those skilled in the art. Therefore, the intent is to be limited only by the scope of the appended claims and not by the specific details presented in the description and explanation of the embodiments herein.

[0221] List of abbreviations:

[0222]

[0223] References

[0224]

Claims

1. A wireless communication device (302), comprising: The wireless interface (308) is configured to wirelessly transmit signals to the receiver; The pre-encoder unit (312) is configured as follows: Obtain the first data signal to be sent and the second data signal to be sent; as well as Perform a first multipath precoding on the first data signal according to a first set of paths between the device and the receiver to obtain a first precoded signal (3221); and The second data signal is subjected to a second multipath precoding based on a second set of paths between the device and the receiver to obtain a second precoded signal (3222); The precoder unit is configured to generate the first precoded signal (3221) and the second precoded signal (3222), such that the second precoded signal (3222) includes the offset of the receiver in the delay / Doppler domain relative to the first precoded signal (3221), wherein the offset includes at least one of delay in the time domain and frequency shift in the Doppler domain; The device is configured to transmit the first precoded signal (3221) and the second precoded signal (3222) with the same transmission radiation characteristics of the wireless interface (308).

2. The apparatus of claim 1, wherein, The wireless communication device is one of a base station (BS) and a user equipment (UE), and the receiver is the other of the base station (BS) and the user equipment (UE).

3. The apparatus of claim 1, wherein, The device is configured to use a single beam having the aforementioned transmission radiation characteristics to simulate multi-beam transmission of a signal to a receiver, the single beam being used to transmit the first precoded signal (3221) and the second precoded signal (3222), the single beam being a single beam or a superposition of beams.

4. The apparatus of claim 1, wherein, The pre-encoder unit is configured to obtain channel information related to the multipath propagation of signals from the device to the receiver; And it is used to select the first group of paths and the second group of paths from multi-path propagation.

5. The apparatus of claim 1, wherein, The wireless interface is configured to form at least one beam from a set of beams using beamforming technology; wherein the device is configured to transmit a first precoded signal (3221) and a second precoded signal (3222) using a single beam or a subset of a beam set.

6. The apparatus of claim 1, wherein, The precoder unit (312) includes a first branch (3361) having a first precoder (3181), the first precoder (3181) being configured to obtain the first data signal or a signal derived therefrom, and the first branch (3361) being configured to generate the first precoded signal (3221) based on the first precoder (3181); and The precoder unit includes a second branch (3362) having a second precoder (3182) and an offset filter (326), the offset filter (326) being configured to provide the offset in the delay / Doppler domain, the second branch (3362) being configured to obtain the second data signal or a signal derived therefrom, and the second branch being configured to generate the second precoded signal (3222) based on the second precoder (3182) and the offset filter (326).

7. The device according to claim 1, wherein The precoder unit (312) is configured to obtain the second precoded signal (3222) offset by a delay (Δt) in the delay domain relative to the first precoded signal (3221), the delay being at most the maximum channel delay between the device and the receiver; and / or The pre-encoder unit (312) is configured to obtain the second pre-encoded signal (3222) with an offset of a frequency shift in the Doppler domain relative to the first pre-encoded signal (3221), the frequency shift being at most the maximum Doppler spread of the wireless network operated by the device.

8. The apparatus of claim 1, wherein, The precoder unit (312) is configured to obtain the second precoded signal (3222) offset by a delay (Δt) in the delay domain relative to the first precoded signal (3221), the delay being at most the duration of a symbol of the first or second precoded signal (3221; 3222).

9. The apparatus of claim 1, wherein, The precoder unit (312) is configured to obtain the second precoded signal (3222) offset by a delay (Δt) in the delay domain relative to the first precoded signal (3221), the delay being at most the symbol sampling rate at the receiver.

10. The device according to claim 1, wherein, The precoder unit (312) is configured to obtain the second precoded signal (3222), offset by a delay (Δt) relative to the first precoded signal (3221), the delay corresponding to one of the following within a tolerance range: - An algebraic fraction of the duration of the symbol; - An algebraic fraction of the length of the protection interval; - An algebraic fraction or multiple of the correlation or effective length of the channel impulse response between the device and the receiver; and - A multiple of the sampling rate of the pre-encoder unit; and / or The pre-encoder unit (312) is configured to obtain a second pre-encoded signal (3222) offset by a frequency shift in the Doppler domain relative to the first pre-encoded signal (3221), the frequency shift corresponding to one of the following within a tolerance range: - The algebraic fraction of the effective Doppler shift in the correlated Doppler spectrum; - The algebraic fraction of the length of the relevant channel impulse response; - An algebraic fraction or multiple of the subcarrier spacing of the wireless network in which the device operates; and - An algebraic fraction of the system bandwidth of the wireless network in which the device operates.

11. The apparatus of claim 1, wherein, The device is configured to transmit the first precoded signal (3221) and the second precoded signal (3222) as a superposition in the time domain.

12. The device according to claim 1, wherein, The precoder unit is configured to obtain the first precoded signal (3221) based on a first filter that matches the multipath components of the first group of paths; and to obtain the second precoded signal (3222) based on a second filter that matches the multipath components of the second group of paths.

13. The device according to claim 12, wherein, The device is configured to obtain channel impulse response information indicating the multipath components of the first set of paths and the second set of paths based on at least one of the following: Pilot and / or reference symbols previously transmitted in the uplink and / or downlink directions; Information indicating the representation of a radio channel; The receiver's report; as well as The prior knowledge of the channel impulse response information.

14. The device according to claim 13, wherein, The device is configured to obtain channel impulse response information indicating a first channel impulse response and a second channel impulse response based on a report from the receiver, wherein the report is compressed using lossless or lossy compression.

15. The device according to claim 1, wherein, The precoder unit is configured to apply windowing to precode the first data signal and the second data signal.

16. The device according to claim 1, wherein, The precoder unit is configured to precode the data signal based on at least a third path between the device and the receiver to obtain a third precoded signal, thereby including a time offset at the receiver relative to the first precoded signal (3221) and the second precoded signal (3222).

17. The device according to claim 1, wherein, The device is configured to transmit a wireless signal comprising a first component based on the first precoded signal (3221) and a second component based on the second precoded signal (3222); The pre-encoder unit (312) is configured to generate the first pre-encoded signal (3221) and the second pre-encoded signal (3222) such that the first component and the second component are offset relative to each other in the delay / Doppler domain at the receiver.

18. The device according to claim 1, wherein, The device is configured to transmit capability information indicating that the device is configured to transmit the first precoded signal (3221) and the second precoded signal (3222) with the same transmission radiation characteristics of the wireless interface.

19. The device according to claim 18, wherein, The device is configured to send the capability information to include information related to at least one of the device's location, scenario, and mobile cluster.

20. The device according to claim 1, wherein, The device is configured to receive capability information indicating that the receiver is capable of decoding a combination of the first precoded signal (3221) and the second precoded signal (3222), wherein the device is configured to select to transmit the first precoded signal (3221) and the second precoded signal (3222) with the same transmission radiation characteristics of the wireless interface or without based on the capability information.

21. The device according to claim 1, wherein, The device is configured to receive a request message indicating that the device is requested to transmit the first precoded signal (3221) and the second precoded signal (3222) with the same transmission radiation characteristics of the wireless interface; wherein the device is configured to operate according to the request.

22. The device according to claim 1, wherein, The device is configured to obtain channel information indicating a channel between the device (302) and the receiver, the channel information indicating a channel quality higher than a channel quality threshold; and to transmit the first precoded signal (3221) and the second precoded signal (3222) with the same transmission radiation characteristics of the wireless interface based on the channel information.

23. The device according to claim 1, wherein, The device is configured to transmit delay information representing the time delay between symbols of at least the first precoded signal (3221) and the second precoded signal (3222).

24. The device according to claim 1, wherein, The device includes a single transmit antenna or antenna array or active antenna or antenna port for transmitting the signal in a multiplexing mode.

25. The apparatus of claim 1, adapted to deviate from the transmission of a signal relative to timing advance and / or frequency correction in response to an instruction received from a coordinator, such that the arrival of the signal at the receiver side includes an offset relative to the coordination or synchronization schedule.

26. The device according to claim 1, wherein, The device is configured to generate a transmission signal with an effective signal bandwidth lower than that achievable at a given sampling rate supported by the digital-to-analog converter of the pre-encoder unit (312).

27. A wireless communication device configured to obtain capability information indicating a number of offset symbols of a data signal transmitted by a transmitter, the device comprising: The wireless interface is configured to receive wireless signals. The decoder unit is configured to sample the combined data signal received through the wireless interface to obtain a sampled representation of the combined data signal; Used to identify a number of offset symbols in the sampled representation; the number of offset symbols is based on the capability information, wherein the combined data signal includes a first precoded signal and a second precoded signal that are respectively multipath precoded according to a first set of paths and a second set of paths; The decoder unit is configured to separate multiple offset data signals based on the combined data signals to obtain at least a first data stream and a second data stream; The signal is offset in the delay / Doppler domain, wherein the offset includes at least one of delay in the time domain and frequency shift in the Doppler domain.

28. The device according to claim 27, wherein, The device is configured to determine quality information indicating that the channel quality of a wireless signal transmitter is higher than a quality threshold; and to send a request to the wireless signal transmitter requesting the transmission of symbols of another signal transmitted by the transmitter as multiple time-delayed versions of the symbols.

29. The device according to claim 27, wherein, The device is configured to sample the combined data signals to parse the transmitted signals, which have a signal bandwidth lower than the achievable signal bandwidth, i.e., a sampling rate higher than that required to satisfy the Nyquist criterion.

30. A wireless mobile communication network (300), comprising: At least one wireless communication device according to claim 1; as well as Receiver.

31. The wireless mobile communication network according to claim 30, wherein, The receiver is a wireless communication device according to claim 27.

32. A method for operating a device, the method comprising: Obtain the first data signal to be sent and the second data signal to be sent; The first data signal is precoded using a first multipath method based on a first set of paths between the device and the receiver to obtain a first precoded signal (3221); The second data signal is subjected to a second multipath precoding based on the second set of paths between the device and the receiver to obtain a second precoded signal (3222). The first precoded signal (3221) and the second precoded signal (3222) are generated such that the second precoded signal (3222) includes an offset relative to the first precoded signal (3221) in the delay / Doppler domain at the receiver, wherein the offset includes at least one of a delay in the time domain and a frequency shift in the Doppler domain; and The first precoded signal (3221) and the second precoded signal (3222) are transmitted with the same transmission radiation characteristics of the wireless interface.

33. A method for operating a device, the method comprising: The ability to obtain information indicating multiple offset symbols of a data signal transmitted by the transmitter, offset in the delay / Doppler domain: The combined data signals received wirelessly are sampled to obtain a sampled representation of the combined data signals, wherein the received combined data signals include a first precoded signal and a second precoded signal that are respectively multipath precoded according to a first set of paths and a second set of paths, and wherein the offset includes at least one of a delay in the time domain and a frequency shift in the Doppler domain. Identify a number of offset symbols in the sampled representation; the number of offset symbols is based on the capability information; Multiple offset data signals are separated based on the combined symbolic data signals to obtain at least a first data stream and a second data stream.

34. A computer-readable digital storage medium having a computer program having program code stored thereon, which, when run on a computer, performs the method according to claim 32 or 33.

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