OFDM-based compressed data spreading transmission method and apparatus

Abstract

The present disclosure relates to a communication technique and system thereof that integrates a 5G communication system with IoT technology to support a higher data transmission rate after the 4G system. The present disclosure is applicable to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security and safety-related services, etc.) based on 5G communication technology and IoT-related technology. A method of a transmitter of a communication system of the present disclosure is characterized in that it transmits configuration information for signal transmission to a receiver, checks resources for signal transmission, transmits scheduling information indicating the resources to the receiver, converts a transmission signal into a compressed signal corresponding to the configuration information, spreads the compressed signal multidimensionally, maps a part of the spread compressed signal to the resources corresponding to the scheduling information, converts the spread compressed signal to generate an orthogonal frequency-division multiplexing (OFDM) signal, and transmits the generated OFDM signal to the receiver.

Description

[Technical Field]

[0001] The present disclosure relates to techniques for processing signals in wireless communication systems, and more particularly to methods and apparatus for transmitting signals for data transmission in orthogonal frequency division multiplexing (OFDM) based systems. [Background technology]

[0002] Since the commercialization of 4G communication systems, efforts have been made to develop improved 5G or pre-5G communication systems to meet the ever-increasing demand for wireless data traffic. For this reason, 5G or pre-5G communication systems are referred to as beyond-4G network (Beyond 4G Network) communication systems or post-LTE (long term evolution) systems. To achieve high data transmission rates, 5G communication systems are being considered for implementation in ultra-high frequency (mmWave) bands (e.g., the 60 GHz (80 GHz) band). To mitigate radio wave path loss and increase radio wave propagation distance in ultra-high frequency bands, beamforming, massive MIMO, full dimensional MIMO (FD-MIMO), array antennas, analog beamforming, and large scale antenna technologies are being discussed for 5G communication systems. In addition, to improve the system's network, technologies being developed for 5G communication systems include advanced small cells, improved small cells, cloud radio access networks (cloud RAN), ultra-dense networks, device-to-device communication (D2D), wireless backhaul, moving networks, cooperative communication, CoMP (Coordinated Multi-Points), and interference cancellation.In addition, 5G systems are being developed with advanced coding modulation (ACM) methods such as FQAM (Hybrid FSK and QAM Modulation) and SWSC (Sliding Window Superposition Coding), as well as advanced connection technologies such as FBMC (Filter Bank Multi Carrier), NOMA (non-orthogonal multiple access), and SCMA (sparse code multiple access).

[0003] Meanwhile, the Internet is evolving from a human-centered network where humans generate and consume information to an IoT (Internet of Things) network where information is exchanged and processed among distributed components such as objects. IoE (Internet of Everything) technology, which combines IoT with big data processing technology using connections to cloud servers, is also emerging. To realize IoT, technological elements such as sensing technology, wired and wireless communication and network infrastructure, service interface technology, and security technology are required. Recent research has focused on sensor networks for connecting objects, machine-to-machine (M2M) communication, and machine-type communication (MTC). In an IoT environment, intelligent IT (Internet Technology) services can be provided that create new value in people's lives by collecting and analyzing data generated between connected objects. By integrating and combining existing IT (information technology) with various industries, IoT can be applied to areas such as smart homes, smart buildings, smart cities, smart or connected cars, smart grids, healthcare, smart home appliances, and advanced medical services.

[0004] Therefore, various attempts are being made to apply 5G communication systems (5th generation communication systems or New Radio (NR)) to IoT networks. For example, technologies such as sensor networks, machine-to-machine (M2M) communication, and MTC (machine-type communication) are being implemented using 5G communication techniques such as beamforming, MIMO, and array antennas. The application of cloud radio access networks (cloud RAN) as the aforementioned big data processing technology is also an example of the fusion of 3eG and IoT technologies.

[0005] Furthermore, in order to realize a higher data transmission rate in future communication systems, methods of transmitting signals in an ultra-high frequency band are being studied. Summary of the Invention [Problem to be solved by the invention]

[0006] An object of the present disclosure is to provide a method and apparatus for transmitting data that is robust against noise in a system in which the internal noise of the transmitter and receiver is large, such as in the ultra-high frequency or terahertz wave band. [Means for solving the problem]

[0007] To solve the above problems, the present invention is a method for a transmitter in a wireless communication system, which is characterized by including the steps of transmitting configuration information for signal transmission to a receiver, converting the transmission signal into a compressed signal corresponding to the configuration information, multi-dimensionally spreading the compressed signal, mapping a portion of the spread signal in time and frequency according to scheduling information, multiplexing it with other signals to generate an OFDM signal, and transmitting the generated OFDM signal.

[0008] The method further includes transmitting or allowing the transmitter to recognize the degree of Doppler spread or channel spread or corresponding profile information by channel information feedback from the receiver.

[0009] Also, the present invention provides a method for a receiver in a wireless communication system, characterized by including the steps of receiving setting information for signal reception from a transmitter, receiving scheduling information for signal reception from the transmitter, restoring the received signal based on the setting information and the scheduling information, and decompressing the restored signal to obtain transmission information.

[0010] The transmitter of the wireless communication system includes a transceiver unit, and a controller connected to the transceiver unit that transmits configuration information for signal transmission to a receiver, generates a transmission signal based on the configuration information, transmits control information including resource allocation information instructing the receiver of signal allocation resources, generates a transmission signal by applying multidimensional spreading to modulation symbols to be transmitted, and controls the receiver to transmit the generated transmission signal using the signal allocation resources.

[0011] The receiver of the wireless communication system includes a transceiver unit and a controller connected to the transceiver unit, which receives configuration information for signal transmission from a transmitter, stores samples for signal processing for generating a transmission signal based on the configuration information, receives control information including resource allocation information indicating signal allocation resources from the transmitter, receives a received signal from the transmitter using the signal allocation resources, and restores compressed data information in the received signal. [Effects of the Invention]

[0012] According to one embodiment of the present disclosure, transmission data is compressed and then multidimensionally spread before being transmitted, thereby achieving excellent signal restoration capability in a system with a lot of internal noise, and in particular, enabling effective signal restoration even when only a portion of the spread signal is transmitted. [Brief explanation of the drawings]

[0013] [Figure 1] 1 is a diagram showing the basic structure of a time-frequency domain, which is a radio resource domain in which data or control channels of a 5G system are transmitted. [Figure 2] A diagram showing the structure of frames, subframes and slots in a 5G system. [Figure 3] FIG. 1 is a diagram showing an example of a resource grid of a dD domain proposed in the present invention. [Figure 4] FIG. 1 is a diagram showing an example of diffusion into the tf domain proposed in the present invention. [Figure 5] FIG. 1 is a diagram showing an example of tf domain resource allocation proposed in the present invention. [Figure 6] FIG. 2 is a diagram illustrating a transmission operation of a transmitter proposed in the present invention. [Figure 7] FIG. 2 is a diagram illustrating the receiving operation of the receiver proposed in the present invention. [Figure 8] FIG. 10 shows the performance of an example of the proposed invention. [Figure 9] FIG. 10 is another diagram illustrating the performance of an example of the proposed invention. [Figure 10] FIG. 10 is another diagram illustrating the performance of an example of the proposed invention. [Figure 11] FIG. 10 is another diagram illustrating the performance of an example of the proposed invention. [Figure 12] FIG. 10 is another diagram illustrating the performance of an example of the proposed invention. [Figure 13] FIG. 2 is a block diagram illustrating the structure of a transmitter according to an embodiment of the present disclosure. [Figure 14] FIG. 2 is a block diagram illustrating the structure of a receiver according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE INVENTION

[0014] Hereinafter, embodiments of the present disclosure will be described in detail with reference to the accompanying drawings.

[0015] In the description of the embodiments, technical content that is well known in the technical field to which the present disclosure pertains and is not directly related to the present disclosure will be omitted in order to more clearly convey the gist of the present disclosure without obscuring it.

[0016] For the same reason, some components in the accompanying drawings are exaggerated, omitted, or schematically illustrated, and the size of each component does not entirely reflect the actual size. In each drawing, the same or corresponding components are given the same reference numerals.

[0017] The advantages and features of the present disclosure, as well as methods for achieving them, will become clearer with reference to the following detailed description of the embodiments in conjunction with the accompanying drawings. However, the present disclosure is not limited to the embodiments described below, and may be embodied in various other forms. The embodiments of the present disclosure are provided solely to complete the disclosure and to fully convey the scope of the invention to those skilled in the art to which the present disclosure pertains. The present disclosure is defined only by the scope of the claims. The same reference symbols refer to the same elements throughout the specification.

[0018] It will be understood that each block of the process flow diagram and combinations of the flow diagrams can be implemented by computer program instructions. These computer program instructions can be loaded into a processor of a general-purpose computer, special-purpose computer, or other programmable data processing device, such that the instructions, executed by the processor of the computer or other programmable data processing device, create means for performing the functions described in the flow diagram blocks. These computer program instructions can also be stored in computer-usable or computer-readable memory that can direct a computer or other programmable data processing device to implement the functions in a particular way, such that the instructions stored in the computer-usable or computer-readable memory can produce an article of manufacture incorporating instruction means for performing the functions described in the flow diagram blocks. Computer program instructions may be embodied on a computer or other programmable data processing device such that a series of operational steps are performed on the computer or other programmable data processing device to create a computer-implemented process, causing the computer or other programmable data processing device to perform the instructions, which may provide steps for performing the functions described in the flowchart blocks.

[0019] Also, each block may represent a module, segment, or portion of code that includes one or more executable instructions for performing a specific logical function. Also, it should be noted that in some alternative implementations, the functions noted in the blocks may occur out of order. For example, two blocks shown in succession may in fact be performed substantially simultaneously, or the blocks may often be performed in reverse order depending on the function involved.

[0020] In this embodiment, the term "module" refers to software or hardware components such as a field programmable gate array (FPGA) or an application specific integrated circuit (ASIC), and the "module" may perform either function. However, the term "module" is not limited to software or hardware. The "module" may be configured to reside on an addressable storage medium or to implement one or more processors. Accordingly, in some embodiments, the "module" includes components such as software components, object-oriented software components, class components, and task components, as well as processes, functions, attributes, procedures, subroutines, program code segments, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The components and functions provided by the "module" may be combined into a smaller number of components and "modules" or further separated into additional components and "modules." Furthermore, the components and "modules" may be embodied to implement one or more CPUs within a device or a secure multimedia card. In some embodiments, the "module" may also include one or more processors.

[0021] The operating principle of the present technical concept will be described in detail below with reference to the accompanying drawings. In the following description of the present technical concept, if a detailed description of related known functions or configurations is deemed to obscure the gist of the present invention, such detailed description will be omitted. Furthermore, the terms used below are defined in consideration of the functions of the present invention, and may vary depending on the intentions or practices of users or operators. Therefore, the definitions should be based on the entire contents of this specification.

[0022] Hereinafter, a base station is an entity that allocates resources to a terminal, and may be at least one of a gNode B, an eNode B, a Node B, a BS (Base Station), a radio access unit, a base station controller, or a node on a network. A terminal may include a UE (User Equipment), an MS (Mobile Station), a cellular phone, a smartphone, a computer, or a multimedia system that may have a communication function. Of course, the present disclosure is not limited to these examples. Hereinafter, the present disclosure describes a technique for a terminal to receive broadcast information from a base station in a wireless communication system. This disclosure is directed to a 4G (4G) th 5G (5 generation) system to support higher data transmission rates th The present disclosure relates to a communication technique and system that integrates a 5G (5G generation) communication system with IoT (Internet of Things) technology. The present disclosure may be applied to intelligent services (e.g., smart homes, smart buildings, smart cities, smart cars or connected cars, healthcare, digital education, retail, security and safety-related services, etc.) based on 5G communication technology and IoT-related technologies.

[0023] In the following description, terms indicating broadcast information, control information, communication coverage, status changes (e.g., events), network entities, messages, and device components are used as examples for the convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0024] For the sake of convenience, some of the terms and names defined in the 3GPP (3rd generation partnership project) LTE or NR standard may be used below. However, the present invention is not limited to the above terms and names and may be equally applied to systems conforming to other standards.

[0025] Wireless communication systems have evolved from their initial voice-centric service offerings to broadband wireless communication systems that provide high-speed, high-quality packet data services, such as communication standards such as 3GPP® High Speed Packet Access (HSPA), LTE (or Evolved Universal Terrestrial Radio Access (E-UTRA)), LTE-Advanced (LTE-A), LTE-Pro, 3GPP®2 High Rate Packet Data (HRPD), Ultra Mobile Broadband (UMB), and IEEE 1102.16e.

[0026] In an LTE system, which is a representative example of a broadband wireless communication system, an orthogonal frequency division multiplexing (OFDM) scheme is adopted in the downlink (DL), and a single carrier frequency division multiple access (SC-FDMA) scheme is adopted in the uplink (UL). The uplink refers to a radio link through which a terminal transmits data or control signals to a base station, and the downlink refers to a radio link through which a base station transmits data or control signals to a terminal. In the above multiple access scheme, time-frequency resources for transmitting data or control information for each user are allocated and operated so as not to overlap with each other, i.e., so as to establish orthogonality, thereby separating the data or control information of each user.

[0027] The future communication system after LTE, i.e., the 5G communication system, must be able to freely reflect various requirements of users and service providers, and must support services that meet various requirements. Services being considered for the 5G communication system include Enhanced Mobile Broadband (eMBB), massive Machine Type Communication (mMTC), and Ultra Reliability Low Latency Communication (URLLC).

[0028] According to some embodiments, eMBB aims to provide a data transmission rate that is even higher than the data transmission rates supported by existing LTE, LTE-A, or LTE-Pro. For example, in a 5G communication system, eMBB must be able to provide a maximum downlink peak data rate of 20 Gbps and a maximum uplink peak data rate of 10 Gbps from the perspective of a single base station. At the same time, it must provide an increased user perceived data rate. To meet these requirements, improved transmission and reception technologies, including improved multiple input multiple output (MIMO) transmission technology, are required. In addition, the data transmission rate required in a 5G communication system can be met by using a frequency band of 3 to 6 GHz or above 6 GHz with a frequency bandwidth wider than 20 MHz, instead of the 2 GHz band currently used by LTE.

[0029] At the same time, mMTC is being considered to support application services such as the Internet of Things (IoT) in 5G communication systems. To efficiently provide the Internet of Things, mMTC may be required to support large-scale terminal connection support within a cell, improve terminal coverage, improve battery life, and reduce terminal costs. The Internet of Things provides communication functions by being attached to various sensors and devices, so a large number of terminals (e.g., 1,000,000 terminals / km) within a cell will be required. 2 ) must be able to support this. In addition, due to the characteristics of the service, devices that support mMTC are likely to be located in shadow areas where cells cannot cover, such as underground areas of buildings, so they may require wider coverage than other services provided by 5G communication systems. Devices that support mMTC must be low-cost devices, and since device batteries are difficult to replace, they may require a very long battery life.

[0030] Finally, URLLC requires mission-critical cellular-based wireless communication services, such as those used for remote control of robots or machinery, industrial automation, unmanned aerial vehicles, remote health care, and emergency alerts, to provide ultra-low latency and ultra-reliable communications. For example, URLLC services must meet air interface latency of less than 0.5 milliseconds and at the same time, must be able to provide up to 10 -5The following packet error rate requirements are required. Therefore, for services that support URLLC, a 5G system must provide a smaller transmit time interval (TTI) than other services, and at the same time, a design requirement is required to allocate wider resources in the frequency band. However, the above-mentioned mMTC, URLLC, and eMBB are merely examples of different service types, and the service types to which the present disclosure is applicable are not limited to these examples.

[0031] The services considered in the above-mentioned 5G communication system need to be integrated and provided based on one framework, i.e., for efficient resource management and control, it is preferable that the services are integrated, controlled, and transmitted in one system rather than being operated independently.

[0032] The frame structure of the 5G system will be described in more detail below with reference to the drawings.

[0033] FIG. 1 is a diagram showing the basic structure of a time-frequency domain, which is a radio resource domain in which data or control channels of a 5G system are transmitted.

[0034] Referring to FIG. 1, the horizontal axis represents the time domain and the vertical axis represents the frequency domain. In the time and frequency domains, the basic unit of a resource is a resource element (RE) (100), which may be defined as one OFDM symbol (110) on the time axis and one subcarrier (120) on the frequency axis. In the frequency domain,

number

[0035] FIG. 2 is a diagram illustrating the structure of frames, subframes, and slots in a 5G system.

[0036] Referring to FIG. 2, an example of a structure of a frame (200), subframes (210), and slots (220) is shown. One frame (200) may be defined as 10 ms. One subframe (210) may be defined as 1 ms, and one frame (200) may consist of a total of 10 subframes (210). One slot (220, 230) may be defined as 14 OFDM symbols (i.e., the number of symbols per slot is 14).

number

[0037] In the example of Figure 2, the subcarrier spacing setting value μ = 0 (240) and μ = 1 (250) are shown. When μ = 0 (240), one subframe 210 may consist of one slot 2220, and when μ = 1 (250), one subframe (210) may consist of two slots (230). In other words, the number of slots per subframe is determined by the setting value μ for the subcarrier spacing.

number

number

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[0038] [Table 1]

[0039] In NR, one component carrier (CC) or serving cell may be configured with a maximum of 250 or more RBs. Therefore, if a terminal always receives signals over the entire serving cell bandwidth, as in an LTE system, power consumption of the terminal becomes significant. To address this issue, a base station can configure one or more bandwidth parts (BWPs) in the terminal and support the terminal in changing the signal reception area within the cell. In NR, a base station can configure an initial BWP, which is the bandwidth of CORESET #0 (or common search space, CSS), in the terminal via a master information block (MIB). The base station then configures the terminal's first BWP via radio resource control (RRC) signaling and can subsequently notify at least one BWP configuration information that can be indicated by downlink control information (DCI). The base station can then inform the terminal of which band to use by announcing a BWP ID via DCI. If the terminal is unable to receive DCI in the currently assigned BWP after a certain time has elapsed, the terminal may return to the basic bandwidth (default BWP) and attempt to receive DCI.

[0040] Next, we will explain in detail the downlink control information (DCI) in the 5G system.

[0041] In a 5G system, scheduling information for uplink data (or physical uplink data channel (PUSCH)) or downlink data (or physical downlink data channel (PDSCH)) is transmitted from a base station to a terminal via DCI. The terminal can monitor a fallback DCI format and a non-fallback DCI format for the PUSCH or PDSCH. The fallback DCI format may be configured with fixed fields predefined between the base station and the terminal, and the non-fallback DCI format may include configurable fields.

[0042] The DCI may be transmitted on a physical downlink control channel (PDCCH) that is a physical downlink control channel after undergoing channel coding and modulation processes. A cyclic redundancy check (CRC) is attached to the DCI message payload, and the CRC is scrambled with a radio network temporary identifier (RNTI) corresponding to the identity of the terminal. Different RNTIs are used depending on the purpose of the DCI message, for example, UE-specific data transmission, power control command, or random access response. That is, the RNTI is not explicitly transmitted, but is transmitted after being included in the CRC calculation process. Upon receiving a DCI message transmitted on the PDCCH, the terminal checks the CRC using the assigned RNTI, and if the CRC check result is correct, the terminal knows that the message was transmitted to the terminal.

[0043] DCI format 1_0 may be used as an alternative DCI for scheduling a PDSCH, and in this case, the CRC may be scrambled with the C-RNTI. DCI format 1_0 with the CRC scrambled with the C-RNTI may include, for example, the information in Table 2 below.

[0044] [Table 2]

[0045] DCI format 1_1 may be used as a non-alternative DCI for scheduling a PDSCH, and in this case, the CRC may be scrambled with the C-RNTI. DCI format 1_1 with the CRC scrambled with the C-RNTI may include, for example, the information in Table 3 below.

[0046] [Table 3]

[0047] In the transmission process of an OFDM signal in a 5G system, encoded symbols (or encoded bits) are converted into modulated symbols through modulation, and M modulated symbols are then converted into parallel signals using a serial-to-parallel (S / P) converter. The converted M symbols are mapped to desired subcarrier positions and then converted into an OFDM signal using an inverse fast Fourier transform (IFFT). The converted time samples are converted into serial time samples using a parallel-to-serial (P / S) converter, concatenated with a cyclic prefix, and then passed through a digital-to-analog converter (DAC) and radio frequency (RF) to generate a signal. This OFDM signal can be transmitted from low to high frequency bands. However, when a high frequency band is used, the high sampling rate, wide bandwidth, and low hardware efficiency require very high power consumption, so the receiver cannot remain active all the time and can only wake up for a short time when receiving data. In order for the receiver to wake up and receive and process data within a very short time interval while minimizing performance degradation, sufficient additional information must be present before receiver signal processing begins. In existing cellular communication systems, a portion of the resources (typically 20% or more) is used to transmit and receive pilot signals to assist in acquiring channel information necessary for time, frequency, and / or Doppler synchronization and demodulation.

[0048] The bottleneck phenomena that occur when processing signals in such high frequency bands in a short time are as follows: First, phase noise occurs, which is a change in phase due to internal noise generated in RF devices, and this causes a serious degradation of receiver performance. That is, when the frequency band used for signal transmission and reception is significantly higher, it is much more difficult to achieve the same level of reception accuracy using the same amount of resources for pilot signals. Therefore, a method is needed to obtain desired data channel information from signals damaged by such noise while minimizing the required overhead.

[0049] In the following, "d" denotes the delay domain of the channel, "D" denotes the Doppler domain of the channel, "t" denotes the time domain of the channel, and "f" denotes the frequency domain of the channel. "dD" denotes the two-dimensional domain of delay and Doppler, and "tf" denotes the two-dimensional domain of time and frequency.

[0050] According to the method proposed in this invention, the transmitter allocates a dD resource grid (i.e., N d ×N D In fact, the data packets are mapped onto the tf resource grid (i.e., N F ×N T For this purpose, the transmitter and receiver use the second-order statistics (2 nd order statistics), i.e., Doppler spread L D (in symbols) and delay spread L dTo obtain information about the channel state information (sample unit), the receiver or transmitter feeds back the channel information obtained based on the channel and / or signal (e.g., channel state information reference signal (CSI-RS), synchronization signal, etc.) to the transmitter or receiver, or obtains the corresponding channel information using an obtainable channel and signal (e.g., sounding reference signal (SRS)). As a result, the number of two-dimensional resources available in the dD domain is reduced to N d ×N D =N F / L d ×N T / L D As stated above.

[0051] 3 is a diagram showing an example of a resource grid in the dD domain. The dD domain has Nd (307) block resources that indicate delay and Nd blocks that indicate Doppler. D It may be expressed as a two-dimensional grid (301) consisting of (303) block resources. One block (311) in the two-dimensional grid is L d 305 and L D The resource is divided equally into 309 two-dimensional dD domain resources having a length of p(1) to p(N). This division may be performed according to the time delay and Doppler spread of the channel, and the information on the division may be determined by the base station based on the maximum allowable delay and moving speed of the designed terminal and may be preset in higher layer signaling, or may be set based on the channel known by channel estimation using SRS or CSI-RS between the transmitter and receiver and feedback on the channel and may include at least one of the following methods indicated by higher layer signaling. The divided resources are referred to as p(1) to p(N). d ,N D ) block resources may be configured.

[0052] The method proposed in the present invention is as follows: A transmitter first converts a transmission symbol (or transmission information) into binary information by sparse mapping. Here, binary information refers to a value of 0 or 1, and sparse mapping refers to mapping using a converted vector containing a very small number of 1s. There are various methods for sparse mapping, but one example is a method of converting a specific position of a converted vector into 1. For example, by converting a 2-bit transmission symbol into a 4-bit sparse vector, 00 can be converted into 1000, 01 into 0100, 10 into 0010, and 11 into 0001. Here, since each converted sparse vector contains one 1, the sparseness K is expressed as 1.

[0053] The transformed vector is then mapped to a dD resource grid and transformed into a tf-domain signal, after which a portion of the transformed tf-domain signal is selected by scheduling and transmitted as an OFDM signal.

[0054] The receiver first receives the OFDM symbols and converts them into dD domain signals. The receiver uses a CS (compressed sensing)-based reception algorithm, and can check the presence or absence of dD domain signal information for each dD block resource to recover the desired binary signal using CS energy sensing. The recovered binary signal is then converted back to the original symbols by sparse demapping.

[0055] Next, the proposed transmission method will be described in more detail. If a binary transmission vector (i.e., one or more transmission symbols) transmitted in the delay-Doppler domain is denoted by s, the sparse vector p may be obtained by a function f(s; b; M; K). That is, each b-bit stream corresponding to each binary transmission vector s is converted into an M-dimensional sparse vector (where, for example, M=bN) by a mapper with rarity K. d N D / N s , Ns is mapped to the length of s). As a result, the maximum number of resources in the dD domain is N d ×N D The blocks are sparse matrix p, and data (0 or 1) is mapped to each block. Therefore, the mapped p can be expressed as the following sparse matrix P:

[0056]

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[0057] where 1 LDxLd L D / 2 and L d / means a matrix where the second value is 1 and the rest are 0. By spreading the sparse matrix P into the tf domain, a two-dimensional transmitted signal X can be generated as shown in Equation 2 below.

[0058]

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[0059] Here, AoB means the Hadamard product between the A and B matrices. F NF is a Fourier transform matrix of size N, Φ is a selection matrix for selecting m columns in the tf domain, and Φ' is a matrix obtained by permuting Φ in the dD domain. Φ is responsible for selecting a frequency band, and the transmitter uses Φ to perform additional compression in the frequency domain to configure guard bands for user multiplexing and / or potential interference management between adjacent channels.

[0060] Using the above procedure, a total of two stages of compression are applied to the s-vector transmission, the first of which is rarefaction compression in the dD domain, and the second of which is frequency band mapping compression in the tf domain.

[0061] 4 is a diagram showing an example of spreading to the tf domain proposed in the present invention. That is, as shown in FIG. 4, the p blocks configured in FIG. 3 are spread in two dimensions of time 403 and frequency 405. Here, since the transformation to the tf domain is performed by the size of the FFT, the information of all p blocks is uniformly spread in the two-dimensional resource 401. However, it may be impossible to actually transmit all of this information in a communication system. In a communication system, transmitting a signal using a specific frequency resource is necessary for multiplexing with other users and / or for configuring guard bands.

[0062] FIG. 5 is a diagram showing an example of tf domain resource allocation proposed in the present invention. The spread p block information is actually transmitted in a partial region 507 in the band of time 503 and frequency 505 as shown in FIG. 5. At this time, in the first compression (sparse compression in the dD domain) described above, the method is determined by a higher layer signal or a predetermined rule, and in the second compression (signal transmission in a partial region of the tf domain), the transmitter uses a control channel or a higher layer signal to transmit to the receiver the position and length of the frequency band in which the signal is transmitted. Specifically, the information for the first compression is L d and / or L D The length of N d and / or N D The number of N F and / or N T The information for the second compression may include at least one of information regarding the number of sparse vectors, the length of the sparse vector, the method or rule of sparse mapping, the sparseness K, etc. In addition, the information for the second compression may include information regarding the frequency band in which the signal is transmitted, the position of the subcarrier, the frequency resource and / or time resource expressed in a predetermined or set unit, and the position of the time symbol.

[0063] The transmitted signal is received by the receiver through the channel. When this signal is expressed as a vector, the received vector y at symbol n is n may be expressed as Equation 3.

[0064]

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[0065] where G n denotes the channel matrix, and x n means the n-th row vector of the X matrix, and z is a noise vector meaning additive white Gaussian noise. Here, the channel matrix G can be decomposed as shown in the following equation 4.

[0066]

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[0067] where Λ n The matrix represents the frequency channel values in a diagonal form. That is, if the frequency channel vector is h n When

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[0068]

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[0069] The signal compressed into the dD domain is N T symbols are transmitted, so N T A matrix of symbols

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[0070]

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[0071] This is the transformation of the received signal into the dD domain. U is

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number

[0072]

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[0073] Here, in order to restore the received signal using the CS algorithm, Equation 7 is separated into a submatrix, and applying this results in Equation 8.

[0074]

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[0075] Here, the conversion symbol means a conversion such as the following formula 9.

[0076]

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[0077] Finally, the transformed equation 9 can be expressed as follows:

[0078]

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[0079] G is the dD domain channel response, and G is expressed identically for all dD domain resource blocks due to the two-dimensional cyclic correlation property between tf and the dD domain. The receiver can select the resource block with the highest energy for each resource block using Equation 10. This can be expressed mathematically as Equation 11.

[0080]

number

[0081] Because the P matrix is composed of 0s and 1s, the receiver's operation is equivalent to sensing the energy of resource blocks mapped with 1s using a dD channel. Therefore, without using a pilot signal, the receiver can recover the transmitted signal by observing the dD domain where the energy of all channels is received. Also, because a single data symbol is not mapped to a specific resource in the tf domain but is distributed across multiple tf resources, it can be more robust against interference caused by phase noise. The received signal is equivalent to the two-dimensional convolution of the channel impulse response with the rarefaction vector in the dD domain. Consequently, information is conveyed by the presence or absence of a signal in a specific resource block in the dD domain resource grid.

[0082] FIG. 6 is a diagram showing the transmission operation of the transmitter proposed in the present invention. Referring to FIG. 6, the transmitter sets configuration information for compressed transmission of the method proposed in the present invention and transmits it to the receiver using an upper layer signal (601). The configuration information for compressed transmission includes L d and / or L D The length of N d and / or N D The number of N F and / or N TThe scheduling information may include at least one of information regarding the number of sparse vectors, the length of the sparse vector, the method or rule for sparse mapping, the sparseness K, etc., and some of the information may be predetermined and not be transmitted. Then, the transmitter determines specific scheduling information, particularly allocation information on the frequency axis, and transmits the information to the receiver via a control channel or higher layer signaling (603). The scheduling information may include information for the second compression as described above, such as information regarding frequency band resources and / or time resources on which the signal converted by the method proposed in the present invention is transmitted.

[0083] The transmitter then converts the transmission signal into a sparse vector using the method described above (605) and maps it to a preconfigured dD domain block resource (607). The transmitter then converts the signal mapped using the method described above into a tf domain signal (609) and allocates (or maps) it to a tf domain resource based on scheduling information such as the frequency allocation determined in step 603 (611). At this time, the transmitter can multiplex the converted signal with other signals. The transmitter then converts the converted signal into an OFDM signal and transmits it to the receiver (613).

[0084] Figure 7 is a diagram showing the receiving operation of the receiver proposed in the present invention. Referring to Figure 7, the receiver receives configuration information for compressed transmission such as sparse vector compression or mapping rules, dD domain resource configuration information, etc. from the transmitter by an upper layer signal (701). The configuration information for compressed transmission includes: d and / or L D The length of N d and / or N D The number of N F and / or N TThe scheduling information may include at least one of the number of tf vectors, the length of the sparse vector, the method or rule for sparse mapping, the sparseness K, etc., and some of this information may be predetermined and not need to be transmitted. The receiver then receives scheduling information (i.e., OFDM signal allocation information) in the actual tf domain via an upper layer signal or a control channel (703). The scheduling information may include information for the second compression, such as frequency band resources and / or time resources on which the signal converted by the method proposed in the present invention is transmitted. The receiver receives the OFDM signal according to the scheduling information received in step 703. The receiver then recovers the transmitted dD domain sparse vector using a method for measuring the energy magnitude for each dD domain resource block through signal processing as proposed in the present invention to recover the original signal, and then recovers the original signal by sparse vector demapping using the recovered sparse vector.

[0085] Figure 8 is a diagram showing the performance of an example of the proposed invention when the length of the symbols used for data transmission is variable.

[0086] In Figure 8, the number of symbols N t The packet error rate (PER) performance was shown in terms of the signal-to-noise ratio (SNR) when using 20, 40, 60, and 80 dD domain resource blocks. This is because the size of the dD domain resource block used for transmission is constant, but the L constituting the block varies. D This means that the length of the signal is different when transmitting the signal. From this result, we can observe the effect of inter-block interference in the dD domain with a certain Doppler spread. According to Figure 8, the N t It can be seen that if we use = 60 and 80, we can achieve a PER of 0.001. tIf is small, around 20-40, performance will be degraded even if the SNR is high, and PER will not improve. This is because errors occur due to the interference between resource blocks that occurs in the dD domain, which is a phenomenon similar to the inter-symbol interference in the tf domain. In other words, to effectively perform the method proposed in this invention, it is necessary to allocate the dD domain block resource (L ) based on the Doppler spread statistics of the channel to avoid such interference. D , L d It is important to properly configure the magnitude of the eigenvalue (i.e., the magnitude of eigenvalue) so that the transmitter and receiver can acquire the channel state before performing the proposed invention.

[0087] Figure 9 is another diagram showing the performance of an example of the proposed invention, with varying frequency band sizes at different Doppler velocities.

[0088] In FIG. 9, the technique proposed in the present invention is shown to be a Doppler frequency (f D ) and the compression ratio m (%) in the frequency axis. As can be seen from the results in Figure 9, the appropriate Doppler domain block distance L D It can be seen that when setting , it is possible to achieve 0.1 PER (a general data transmission requirement in cellular networks) even when transmitting using frequency resources of only about 40% of the bandwidth. If the Doppler frequency is further reduced (as the terminal speed becomes slower), it can be seen that the data transmission requirement can be achieved even when using only subcarriers of about 10% of the bandwidth. Therefore, the proposed method demonstrates that a high level of frequency domain compression is possible.

[0089] Figure 10 is another diagram showing the performance of an example of the proposed invention, where the degree of sparse mapping and the size of the time symbols used for transmission are varied.

[0090] In Figure 10, the number of time symbols to transmit the signal, N tThe PER performance results according to the sparseness of the dD domain are shown when N is changed. Here, the sparseness ratio α is used to compare the sparseness, which means the number of blocks actually used for transmission among all M blocks. t If is very large (e.g., N t =80), 0.1 PER can be achieved even if α>0.5, but N t The smaller is, the more sensitive is the PER to the scarcity ratio α. For example, N t If =40, a PER of 0.01 cannot be achieved even if the signal is transmitted to only one or two blocks out of 100.

[0091] Figure 11 is another diagram showing the performance of an example of the proposed invention. Figure 11 shows the performance of the proposed method under different channel conditions.

[0092] In Fig. 11, the maximum delay spread (D max ) and the number of taps in the channel (N tap ) PER performance due to channel characteristics is shown by SNR. For example, N tap is 20, and D max was 70, and the 20 taps were uniformly randomly distributed across the 70 taps to produce a channel with high selectivity in the frequency domain. tap D is the same max It can be observed that, while maintaining D, the average delay interval between taps increases, ultimately further increasing the selectivity of the channel. max As the ,decrease, the channel selectivity decreases.,As a result, the SNR required for reception at the 0.01PER point decreases by 2 dB due to the increase in,channel selectivity, but the impact of the tf domain channel change is small.,This means that the proposed method is insensitive to the phase noise added by the tf domain.

[0093] Fig. 12 shows the performance of the fifth embodiment of the proposed invention, and compares the performance with various existing techniques.

[0094] Figure 12 compares the PER performance of our multi-dimensional sparse vector compression (M-PVS) with existing technologies such as OFDM [1], SVC

[22] , and PL-SVC [3] ([1] Zaidi, Ali, et al., “5G Physical Layer: Principles, Models, and Technology Components,” Academic Press, 2018; [2] H. Ji et al., “Sparse Vector Coding of Control Channel for Ultra-Reliable and Low Latency Communications,” IEEE Trans. Wireless Commun., 2017; [3] H. Ji, et al., “Pilot-Less Sparse Vector Coding for Short Packet Transmission,” IEEE Commun. Lett., vol. 8, no. 4, 2019.). OFDM uses 30% of the resources used for transmitting signals as overhead for transmitting two-dimensional pilot signals. Although SVC (sparse vector coding) requires pilot symbols for decoding, it transmits without pilot symbols, resulting in the same resources used for SVC and pilot-less sparse vector coding (PL-SVC). As a result, SVC cannot be efficiently decoded without pilot symbols, resulting in the lowest performance. In PL-SVC, the main assumption of the decoding algorithm is that the channel coefficients are nearly constant throughout the data transmission period. Therefore, even at high SNRs, performance degradation is observed due to Doppler-induced channel variations. Compared to OFDM, the method proposed in this invention (M-SVC) has lower spectral efficiency, but it can achieve better PER performance without the overhead of pilot signals in the tf domain and, as a result, without channel estimation.This is very useful for systems where energy efficiency is more important than spectral efficiency, such as data networks using mmWave or terahertz spectrum, where frequency bandwidth resources are very limited.In addition, each execution step of the proposed M-SVC can be processed at high speed using software in the transceiver without additional hardware.

[0095] The transceiver, memory and processor of the terminal and base station for implementing the above-described embodiments are shown in Figures 13 and 14, respectively.

[0096] 13 is a block diagram illustrating a structure of a transmitter according to an embodiment of the present disclosure, which may be a base station or a terminal.

[0097] 13, the transmitter may include a data signal generator 1300, a multiplexer 1310, a control signal generator 1320, an RF signal generator 1330, and a memory / controller 1340. However, the components of the transmitter are not limited to the above examples, and for example, a terminal may include more or fewer components than the above components. In addition, the data signal generator 1300, the multiplexer 1310, the control signal generator 1320, the RF signal generator 1330, and the memory / controller 1340 may be implemented in the form of a single chip.

[0098] According to an embodiment of the present disclosure, the data signal generator 1300 is a device that modulates transmission symbols to generate transmission samples. The control signal generator 1320 is a device that modulates control information to generate transmission samples. The multiplexer 1310 is a device that multiplexes the generated data and control signals. The RF signal generator 1330 is a device that converts digital signals to analog signals, up-converts them to RF signals, and transmits the generated signals to an antenna. The signals may include control information and data. The RF signal generator 1330 may also be referred to as a transmitter, transceiver, etc.

[0099] According to an embodiment of the present disclosure, the memory / controller 1340 may store programs and data necessary for the operation of the base station. The memory / controller 1340 may also store control information or data included in a signal transmitted by a transmitter. The memory / controller 1340 may be configured as a storage medium, such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media. The memory / controller 1340 may also be configured with a plurality of memories and a processor. According to an embodiment of the present disclosure, the memory / controller 1340 may store information, data, and programs for fast data processing. The operations performed by the multiplexer 1310, the control signal generator 1320, and the data signal generator 1300 may also be performed by the memory / controller 1340.

[0100] According to an embodiment of the present disclosure, the memory / control unit 1340 can control a series of processes according to the operation of the transmitter according to the embodiment of the present disclosure described above.

[0101] 14 is a block diagram illustrating the structure of a receiver according to an embodiment of the present disclosure, which may be a terminal or a base station.

[0102] 14, the terminal may include an RF signal receiver 1440, a data signal receiver 1400, a demultiplexer 1410, a control signal receiver 1420, and a memory / controller 1440. However, the components of the terminal are not limited to the above example, and for example, the terminal may include more or fewer components than the above components. Furthermore, the RF signal receiver 1430, the data signal receiver 1400, the demultiplexer 1410, the control signal receiver 1420, and the memory / controller 1440 may be implemented in the form of a single chip.

[0103] According to an embodiment of the present disclosure, the RF signal receiver 1430 can receive a signal from a transmitter. The signal can include control information and data. To this end, the RF signal receiver 1430 can be configured as an RF receiver that downconverts and amplifies the frequency of the received signal. The RF signal receiver 1430 can also be referred to as a receiver, a transceiver, or the like. The received signal is transmitted via a demultiplexer 1410, with the control channel transmitted to the control signal receiver 1420 and the data channel transmitted to the data signal receiver 1400. The memory / control unit 1440 can then recover the data signal from the control channel based on the recovered command.

[0104] According to an embodiment of the present disclosure, the memory / controller 1440 may store programs and data necessary for the operation of the receiver. The memory / controller 1440 may also store control information or data included in a signal transmitted by a transmitter. The memory / controller 1440 may be configured with a storage medium such as a ROM, a RAM, a hard disk, a CD-ROM, a DVD, or a combination of storage media. The memory / controller 1440 may also be configured with a plurality of memories. According to an embodiment of the present disclosure, the memory / controller 1440 may store information, data, and programs for accelerating data signal processing. The operations performed by the demultiplexer 1410, the control signal receiver 1420, and the data signal receiver 1400 may also be performed by the memory / controller 1440.

[0105] According to an embodiment of the present disclosure, the memory / controller 1440 can control a series of processes so that the base station can operate according to the above-described embodiment of the present disclosure.

[0106] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software.

[0107] When embodied as software, a computer-readable storage medium or computer program product may be provided that stores one or more programs (software modules). The one or more programs stored in the computer-readable storage medium or computer program product are configured for execution by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to perform a method according to the embodiments described in the claims or specification of the present disclosure.

[0108] Such programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, ROM (Read Only Memory), Electrically Erasable Programmable Read Only Memory (EEPROM), magnetic disc storage device, Compact Disc-ROM (CD-ROM), Digital Versatile Discs (DVDs) or other forms of optical storage, magnetic cassette, or in memory configured as a combination of some or all of these. Also, each of these memory configurations may be included in multiple instances.

[0109] The program may also be stored in an attachable storage device accessible through a communication network such as the Internet, an intranet, a local area network (LAN), a wide LAN (WLAN), or a storage area network (SAN), or a combination thereof. Such a storage device can be connected to an apparatus that performs an embodiment of the present disclosure through an external port. Alternatively, a separate storage device on the communication network can be connected to an apparatus that performs an embodiment of the present disclosure.

[0110] In the specific examples of the present disclosure described above, the elements included in the present disclosure are expressed in singular or plural form depending on the specific examples presented. However, the expressions singular or plural are selected appropriately according to the presented circumstances for the convenience of explanation, and the present disclosure is not limited to singular or plural elements, and elements expressed in plural form may be composed of singular elements, and elements expressed in singular form may be composed of plural elements.

[0111] Meanwhile, the embodiments of the present disclosure disclosed in the specification and drawings are merely presented as specific examples to easily explain the technical content of the present disclosure and facilitate understanding of the present disclosure, and are not intended to limit the scope of the present disclosure. That is, it will be apparent to those skilled in the art that other modifications based on the technical concepts of the present disclosure are possible. In addition, the above-described embodiments may be combined with each other as necessary. For example, a base station and a terminal may be operated by combining one embodiment of the present disclosure with a part of another embodiment. In addition, the embodiments of the present disclosure may be applied to other communication systems, and other modifications based on the technical concepts of the embodiments may also be possible. For example, the embodiments may be applied to an LTE system, a 5G system, an NR system, etc. [Explanation of symbols]

[0112] 1300 Data Signal Generator 1310 multiplexer 1320 Control Signal Generator 1330 RF Signal Generator 1340 Memory / Control Unit 1400 Data Signal Receiver 1410 Demultiplexer 1420 Control signal receiver 1430 RF signal receiver 1440 Memory / Control Unit

Claims

1. 1. A method in a transmitter of a communication system, comprising: transmitting configuration information for signal transmission to a receiver; identifying resources for signal transmission and transmitting scheduling information indicating said resources to said receiver; Mapping information included in a signal to be transmitted to a corresponding sparse vector according to the setting information, and converting the signal to be transmitted into a sparse vector; mapping the rarefaction vector to a delay-Doppler domain; converting the mapped sparse vector in the delay-Doppler domain into a signal in the time-frequency domain; mapping a portion of the signal in the time-frequency domain to the resources indicated by the scheduling information; transforming the time-frequency domain signal to generate an orthogonal frequency-division multiplexing (OFDM) signal, and transmitting the generated OFDM signal to the receiver.

2. The method of claim 1, wherein the configuration information includes at least one of information related to a delay-Doppler domain configuration or a sparse mapping rule.

3. The method described in claim 2, characterized in that the delay-Doppler domain setting includes at least one of the number of resources on the delay axis, the number of resources on the Doppler axis, the symbol unit of the delay axis, and the sample unit of the Doppler axis.

4. Mapping the rare vector to the delay-Doppler domain comprises:

4. The method of claim 3, further comprising the step of mapping each bit of the sparse vector to a resource block that constitutes the delay-Doppler domain.

5. 1. A method for a receiver in a communication system, comprising: receiving configuration information for signal reception from a transmitter; receiving scheduling information for the signal reception from the transmitter, the scheduling information indicating resources for signal reception; receiving, from the transmitter, an orthogonal frequency-division multiplexing (OFDM) signal from the resource; converting the received OFDM signal into a delay-Doppler domain signal; determining whether the delay-Doppler domain signal exists in each resource block using compressed sensing, and reconstructing a sparse vector corresponding to information contained in the received OFDM signal based on the determination; and applying sparse demapping on the reconstructed sparse vector to obtain the information.

6. The method of claim 5, wherein the configuration information includes at least one of information related to delay-Doppler domain configuration or sparse mapping rules.

7. The method described in claim 6, characterized in that the delay-Doppler domain setting includes at least one of the number of resources on the delay axis, the number of resources on the Doppler axis, the symbol unit of the delay axis, and the sample unit of the Doppler axis.

8. The method described in claim 5, characterized in that the rare vector is a vector that contains a very small number of 1s and the remainder is 0s.

9. 1. A transmitter for a communication system, comprising: a transmitter / receiver; Transmitting setting information for signal transmission to the receiver; identifying resources for signal transmission and transmitting scheduling information indicating the resources to the receiver; Mapping a sparse vector corresponding to information included in a signal to be transmitted according to the setting information, and converting the signal to be transmitted into a sparse vector; Mapping the rarefaction vector into the delay-Doppler domain; converting the mapped rarefaction vector in the delay-Doppler domain into a signal in the time-frequency domain; Mapping a portion of the signal in the time-frequency domain to the resources indicated by the scheduling information; a controller configured to convert the time-frequency domain signal to generate an orthogonal frequency-division multiplexing (OFDM) signal, and transmit the generated OFDM signal to the receiver.

10. The transmitter of claim 9, wherein the configuration information includes at least one of information related to a delay-Doppler domain configuration or a sparse mapping rule.

11. The transmitter described in Claim 9, characterized in that the delay-Doppler domain setting includes at least one of the number of resources on the delay axis, the number of resources on the Doppler axis, the symbol unit of the delay axis, and the sample unit of the Doppler axis.

12. The transmitter of claim 9, wherein the control unit further controls to map each bit of the sparse vector to a resource block that configures the delay-Doppler domain.

13. 1. A receiver for a communication system, comprising: a transmitter / receiver; receiving setting information for signal reception from the transmitter; receiving scheduling information for the signal reception from the transmitter, the scheduling information indicating resources for signal reception; receiving, from a transmitter, an orthogonal frequency-division multiplexing (OFDM) signal from the resource; converting the received OFDM signal into a delay-Doppler domain signal; determining whether the delay-Doppler domain signal exists in each resource block using compressed sensing, and reconstructing a sparse vector corresponding to information contained in the received OFDM signal based on the determination; and a controller configured to apply sparse demapping on the reconstructed sparse vector to obtain the information.

14. The receiver of claim 13, wherein the configuration information includes at least one of information related to a delay-Doppler domain configuration or a sparse mapping rule.

15. The receiver described in claim 14, characterized in that the delay-Doppler domain setting includes at least one of the number of resources on the delay axis, the number of resources on the Doppler axis, the symbol unit of the delay axis, and the sample unit of the Doppler axis.

16. The receiver of claim 13, wherein the rare vector is a vector containing a very small number of ones and the remainder being zeros.

17. The method described in claim 1, characterized in that the rare vector is a vector that contains a very small number of 1s and the remainder is 0s.

18. A transmitter as described in Claim 9, characterized in that the rare vector is a vector containing a very small number of 1s and the remainder containing 0s.

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