Device and method for decoding channel code in communication system or broadcasting system

Abstract

In embodiments, provided is an electronic device in a communication system or a broadcasting system. The electronic device may comprise at least one processor, and a memory for storing instructions. The instructions, when executed by the at least one processor, may cause the electronic device to: acquire a signal encoded through a channel code; acquire a first input sequence for the signal; determine a change region in the first input sequence on the basis of a lifting size for the channel code and the number of bits to be encoded in a code block; acquire second candidate input sequences corresponding to combinations in which each value of the change region is different on the basis of the first input sequence; and provide a final decoding result by decoding each candidate input sequence from at least some of the second candidate input sequences.

Description

Device and method for decoding channel codes in a communication system or broadcasting system

[0001] The present disclosure relates to a communication system or a broadcasting system. More specifically, the present disclosure relates to a device and method for decoding a channel code in a communication system or a broadcasting system.

[0002] Typically, when transmitting and receiving data between a transmitter and a receiver in a communication and broadcasting system, link performance can be significantly degraded by various forms of noise, fading, and inter-symbol interference (ISI) present in the communication channel. Therefore, to implement high-speed digital communication or broadcasting systems that require high data throughput and reliability, such as next-generation mobile communications, digital broadcasting, and portable Internet, it is necessary to develop technologies to overcome noise, fading, and inter-symbol interference. To overcome errors that may occur in the communication channel at the receiver, error detection codes and error correcting codes (ECC) are utilized. Error correction codes used in communication between a transmitter and receiver are generally referred to as channel coding or forward error correction (FEC). The transmitter encodes the information vector to be transmitted, generates a codeword vector, and transmits it. The receiver performs a series of processing on the received signal, then decodes the processed signal to estimate the information vector.

[0003] Various channel coding techniques are used in communications and broadcasting systems. Current methods include convolutional codes, turbo codes, low-density parity-check coding (LDPC) codes, and polar codes. Turbo and LDPC codes are channel coding techniques that perform iterative decoding. They excel particularly at long-length encodings, and are therefore used in various communications and broadcasting systems.

[0004] Turbo codes were the first channel coding technique to demonstrate performance approaching channel capacity using a decoding algorithm with realistic complexity. Turbo code systems perform decoding by repeatedly exchanging messages between two component decoders, also known as turbo processing. This decoding method shows excellent performance, especially when processing long information and codeword vectors. Because of these advantages, 3GPP (3 rd Generation Partnership Project) 4th generation (4 th It is adopted and used to process information of the data channel of LTE (Long-Term Evolution) generation, 4G.

[0005] LDPC codes are also known as channel coding techniques that achieve performance close to the channel capacity with a decoding algorithm of realistic complexity. In particular, the decoding called belief-propagation (BP) is suitable for parallelizing each detailed operation, which is advantageous in achieving high throughput. Due to these advantages, LDPC codes are used in various communication and broadcasting systems such as IEEE 802.11n / ad Wi-Fi, DVB-T2 / C2 / S2, ATSC 3.0, and especially recently in the 5th generation (5G) th It is also adopted and used in the 3GPP New Radio (NR) system, which is a 5G (5th generation) mobile communication system.

[0006] The above information may be provided as background art to aid in understanding the present disclosure. No claim or determination is made as to whether any of the above-described matters constitute prior art related to the present disclosure.

[0007] In embodiments, an electronic device in a communication system or a broadcasting system is provided. The electronic device may include at least one processor and a memory storing instructions. The instructions, when executed by the at least one processor, may cause the electronic device to obtain a signal encoded through a channel code, obtain a first input sequence for the signal, determine a change region among the first input sequence based on a lifting size for the channel code and a number of bits to be encoded in a code block, obtain second candidate input sequences corresponding to combinations in which each value of the change region is different based on the first input sequence, and decode each candidate input sequence from at least a part of the second candidate input sequences, thereby providing a final decoding result.

[0008] In embodiments, an electronic device in a communication system or a broadcasting system is provided. The electronic device may include at least one processor and a memory storing instructions. The instructions, when executed by the at least one processor, may cause the electronic device to obtain a signal encoded through a channel code, obtain a first input sequence for the signal, determine a change region among a systematic part and a parity part of the first input sequence based on a result of decoding belief-propagation for the first input sequence, obtain second candidate input sequences corresponding to combinations in which each value of the change region is different based on the first input sequence, and decode each candidate input sequence from at least some of the second candidate input sequences, thereby providing a final decoding result.

[0009] In embodiments, an electronic device in a communication system or a broadcasting system is provided. The electronic device may include at least one processor and a memory storing instructions. The instructions, when executed by the at least one processor, may cause the electronic device to obtain a signal encoded through a channel code, obtain a first input sequence for the signal, determine a change region among puncturing bits of a systematic part and puncturing bits of a parity part of the first input sequence, obtain second candidate input sequences corresponding to combinations in which each value of the change region is different based on the first input sequence, and decode each candidate input sequence from at least a part of the second candidate input sequences, thereby providing a final decoding result.

[0010] In embodiments, a decoding method for a channel code in a communication system is provided. The method includes the steps of receiving a signal encoded and transmitted with a used channel code, generating a first decoder input sequence (or vector, array, etc.) from the signal, generating at least one modified second decoder input sequence by modifying at least one element in the first decoder input sequence, performing decoding on each of the at least one modified second decoder input sequence, and determining a final decoding result based on results of the decoding performed on each of the at least one modified second decoder input sequence, wherein at least one element to be modified in the first decoder input sequence can be selected from a limited region determined in consideration of a structure of the channel code.

[0011] In embodiments, a method for decoding a channel code in a communication system is provided. The method may include the steps of receiving a signal encoded and transmitted with a used channel code, generating a first decoder input sequence (or vector, array, etc.) from the signal, performing decoding on the first decoder input sequence, checking a second decoder output sequence generated or updated by the decoding, checking or determining one or more element positions based on the second decoder output sequence, modifying at least one element of the first decoder input sequence based on the element positions checked or determined based on the second decoder output sequence to generate at least one modified third decoder input sequence(s), performing decoding on each of the at least one modified third decoder input sequence(s), and determining a final decoding result based on results of decoding performed on each of the at least one modified third decoder input sequence(s).

[0012] In embodiments, a decoding method for a channel code in a communication system is provided. The method may include the steps of receiving a signal encoded and transmitted with a used channel code, generating a first decoder input sequence (or a vector, an array, etc.) from the signal, generating at least one modified second decoder input sequence by adding one or more elements to the first decoder input sequence, performing decoding on each of the at least one modified second decoder input sequence, and determining a final decoding result based on results of the decoding performed on each of the at least one modified second decoder input sequence. At least one element to be modified in the first decoder input sequence may be selected from a limited region determined in consideration of the structure of the channel code.

[0013] Figure 1 shows an example of a wireless communication system.

[0014] Fig. 2 shows an example of a configuration of a device performing communication in a wireless communication system.

[0015] Figure 3 shows an example of a parity check matrix of an LDPC (low density parity check) code.

[0016] Figure 4 shows an example of a binary graph corresponding to a parity check matrix.

[0017] Figure 5 shows an example of a series of operations for channel encoding.

[0018] Figure 6 shows an example of a series of operations for channel decryption.

[0019] Figure 7 shows an example of the ensemble decoding procedure.

[0020] Figure 8 is a block diagram for ensemble decoding.

[0021] Figure 9 shows an example of a search range for the location of the log likelihood ratio (LLR) to be changed in ensemble decoding.

[0022] Figure 10 shows an example of a limitation on the position of the LLR to be changed in ensemble decoding.

[0023] Figure 11 shows an example of a restriction on the position of an LLR to be changed for ensemble decoding in an intrinsic LLR sequence including a systematic puncture bit.

[0024] Figure 12 shows an example of a restriction on the position of the LLR to be changed for ensemble decoding in an intrinsic LLR sequence that does not include systematic puncture bits.

[0025] Figure 13 shows an example of performance according to restrictions on the location of LLRs to be changed for ensemble decoding.

[0026] Figure 14 shows an example of performance according to restrictions on the location of LLRs to be changed for ensemble decoding.

[0027] Figure 15 is a block diagram for limiting the position of LLR to be changed according to the post-LLR sequence.

[0028] Figure 16 shows examples of restrictions on the position of LLR to be changed according to the post-LLR sequence.

[0029] Figure 17 shows an example of the performance of limiting the position of the LLR to be changed according to the post-LLR sequence.

[0030] Figure 18 shows an example of the performance of limiting the position of the LLR to be changed according to the post-LLR sequence.

[0031] Figure 19 shows an example of the performance of limiting the position of the LLR to be changed according to the post-LLR sequence.

[0032] Figure 20 is a block diagram for ensemble decoding using signal expansion.

[0033] Figure 21 is a block diagram for ensemble decoding using signal expansion.

[0034] Figures 22 to 25 show examples of ensemble decoding using signal expansion.

[0035] Figure 26 shows an example of the performance of ensemble decoding using signal expansion.

[0036] Figure 27 shows an example of a wireless communication system.

[0037] Figure 28 shows network entities according to distributed deployment.

[0038] Figure 29 shows an example of function split of network entities.

[0039] Hereinafter, embodiments of the present invention will be described in detail with the attached drawings.

[0040] The terms used in this disclosure are used only to describe specific embodiments and may not be intended to limit the scope of other embodiments. The singular expression may include plural expressions unless the context clearly indicates otherwise. Terms used herein, including technical or scientific terms, may have the same meaning as commonly understood by those of ordinary skill in the art described in this disclosure. Terms defined in general dictionaries among the terms used in this disclosure may be interpreted as having the same or similar meaning in the context of the relevant technology, and shall not be interpreted in an idealized or overly formal sense unless explicitly defined in this disclosure. In some cases, even if a term is defined in this disclosure, it cannot be interpreted to exclude embodiments of the present disclosure.

[0041] The various embodiments of the present disclosure described below illustrate a hardware-based approach as an example. However, since the various embodiments of the present disclosure include techniques utilizing both hardware and software, the various embodiments of the present disclosure do not exclude a software-based approach.

[0042] In the following description, terms referring to signals (e.g., signal, information, message, signaling), terms referring to data types (e.g., list, set, subset), terms for operational states (e.g., step, operation, procedure), terms referring to data (e.g., packet, user stream, information, bit, symbol, codeword), terms referring to resources (e.g., symbol, slot, subframe, radio frame, subcarrier, resource element (RE), resource block (RB), bandwidth part (BWP), occasion), terms referring to channels, terms referring to network entities, terms referring to components of devices, etc. are examples for convenience of description. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used. In addition, the terms '...bu', '...gi', '...mul', '...che', etc. used below may mean at least one shape structure or a unit that processes a function.

[0043] In describing the embodiments, descriptions of technical details that are well known in the technical field to which the present invention pertains and are not directly related to the present invention will be omitted. This is to avoid obscuring the gist of the present invention by omitting unnecessary explanations and to convey the gist more clearly.

[0044] For the same reason, some components in the attached drawings are highlighted, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0045] The advantages and features of the present invention, and the methods for achieving them, will become clearer with reference to the embodiments described in detail below together with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below and may be implemented in various different forms. These embodiments are provided only to complete the disclosure of the present invention and to fully inform those skilled in the art of the scope of the invention, and the present invention is defined only by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0046] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the computer or the processor of the other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0047] Additionally, each block may represent a module, segment, or portion of code that contains one or more executable instructions for performing a specific logical function(s). It should also be noted that in some alternative implementation examples, the functions described in the blocks may occur out of order. For example, two blocks depicted in succession may actually be executed substantially concurrently, or the blocks may sometimes be executed in reverse order, depending on their respective functions.

[0048] Here, the term '~ unit' used in this embodiment means a software or hardware component such as an FPGA or ASIC, and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to regenerate one or more processors. Thus, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, the components and '~ units' may be implemented to regenerate one or more CPUs within a device or a secure multimedia card.

[0049] Hereinafter, various embodiments will be described in detail with reference to the attached drawings. At this time, it should be noted that the same components in the attached drawings are represented by the same reference numerals as much as possible. In addition, it should be noted that the attached drawings of the present invention are provided to help understand the present invention, and the present invention is not limited to the form or arrangement illustrated in the drawings. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present invention will be omitted. In the following description, only the parts necessary for understanding the operation according to various embodiments of the present invention will be described, and the description of other parts will be omitted so as not to distract from the gist of the present invention.

[0050] In addition, in the present disclosure, expressions such as "more than" or "less than" may be used to determine whether a specific condition is satisfied or fulfilled, but this is merely a description for expressing an example and does not exclude descriptions such as "more than" or "less than." A condition described as "more than" may be replaced with "more than," a condition described as "less than" may be replaced with "less than," and a condition described as "more than and less than" may be replaced with "more than and less than." In addition, hereinafter, "A" to "B" mean at least one of elements from A (including A) to B (including B). hereinafter, "C" and / or "D" mean at least one of "C" or "D," that is, including {"C", "D", "C" and "D"}.

[0051] Although the present disclosure describes various embodiments using terms used in some communication standards (e.g., 3rd Generation Partnership Project (3GPP), European Telecommunications Standards Institute (ETSI), extensible radio access network (xRAN), open-radio access network (O-RAN), etc.), these are merely examples for explanation. The various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0052] The present disclosure relates to a method and apparatus for decoding data with effective and superior error-correction performance in a communication and broadcasting system using turbo codes and low-density parity-check codes (LDPC codes), which gradually update a posterior probability or a metric equivalent thereto for codeword bits through an iterative decoding operation. The present disclosure relates to a communication technique and system for converging a 5G communication system to support a higher transmission rate than a 4G system with IoT technology. The present disclosure can 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 technology. The present disclosure provides an apparatus and method for efficiently decoding bits, symbols, signals, etc. encoded with channel codes such as low-density parity-check (LDPC) codes, turbo codes, etc. and transmitted through a channel in a communication or broadcasting system. In addition, the present disclosure provides an apparatus and method for efficiently realizing and implementing ensemble decoding, which determines a final result by decoding two or more modified LLR sequences generated by changing the value of at least one element in a log-likelihood ratio (LLR) sequence input to a decoder. Specifically, the ensemble decoding method and device according to an embodiment of the present disclosure are characterized in that they determine at least one element whose value is to be changed based on a limited range in consideration of the structure and characteristics of the code being used.In addition, the ensemble decoding method and device according to the embodiment of the present disclosure are characterized in that they attempt decoding based on a decoder input LLR sequence and determine at least one element whose value is to be changed based on a decoder output LLR sequence obtained thereby.

[0053] FIG. 1 illustrates an example of a wireless communication system according to various embodiments of the present disclosure. FIG. 1 illustrates a transmitter (110) and a receiver (120) as part of devices or nodes that utilize a wireless channel in the wireless communication system. Although FIG. 1 illustrates one transmitter (110) and one receiver (120), the wireless communication system may include multiple transmitters or multiple receivers. In addition, for convenience of explanation, the transmitter (110) and the receiver (120) are described as separate entities in the present disclosure, but the functions of the transmitter (110) and the receiver (120) may be interchangeable. For example, in the case of an uplink of a cellular communication system, the transmitter (110) may be a terminal, and the receiver (120) may be a base station or a part of a base station (e.g., a digital unit (DU), a distributed unit (DU), a radio unit (RU), a massive multiple input multiple output (MMU) unit). In the case of downlink, the transmitter (110) may be a base station or a part of the base station (e.g., DU (digital unit), DU (distributed unit), RU, MMU), and the receiver (120) may be a terminal.

[0054] The base station is a network infrastructure that provides wireless access to the terminal. The base station has coverage defined based on the distance at which a signal can be transmitted. In addition to the base station, the base station includes an 'access point (AP)', a 'RAN (radio access network) node', an 'eNodeB (eNB)', and a '5G node (5 th The term "network node" may be referred to as "next generation node (gNB)", "wireless point", "transmission / reception point (TRP)", "communication node", "wireless communication device", "wireless communication equipment", "network node", "network entity", or other terms having equivalent technical meaning.

[0055] The terminal is a device used by a user and communicates with the base station via a wireless channel. The link from the base station to the terminal is referred to as a downlink (DL), and the link from the terminal to the base station is referred to as an uplink (UL). In addition, although not shown in FIG. 1, the terminal and another terminal may communicate with each other via a wireless channel. In this case, the link between the terminal and another terminal (device-to-device link, D2D) is referred to as a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some other embodiments, the terminal may be operated without user intervention. In one embodiment, the terminal is a device that performs machine type communication (MTC) and may not be carried by the user. The above terminal may be referred to as a terminal, or other terms such as 'user equipment (UE),' 'customer premises equipment (CPE),' 'mobile station,' 'subscriber station,' 'remote terminal,' 'wireless terminal,' 'electronic device,' or 'user device,' or other terms having equivalent technical meanings.

[0056] According to one embodiment, the transmitter (110) can generate a codeword by encoding information bits based on a turbo code. The receiver (120) can decode the signal of the received codeword based on the turbo code. For example, the receiver (120) can use the turbo decoding method according to the present invention and check with a concatenated CRC (cyclic redundancy check) code to determine whether the decoding result is normal. The transmitter (110) and the receiver (120) perform encoding and decoding using a structure of a turbo code known to each other (trellis, linear feedback shift register, etc.). For example, the structure of the turbo code may include a trellis, linear feedback shift register, etc. defined in the 3GPP LTE standard.

[0057] According to one embodiment, the transmitter (110) may generate a codeword by encoding information bits based on an LDPC code, and the receiver (120) may decode a signal of the received codeword based on the LDPC code. For example, the receiver (120) may use an LDPC decoding method according to embodiments of the present disclosure. The receiver (120) may perform a syndrome check to determine whether the decoding result is normal. The transmitter (110) and the receiver (120) may perform LDPC encoding and decoding, respectively, using a parity check matrix known to each other. For example, the parity check matrix may include a parity check matrix defined in the 3GPP NR standard.

[0058] Fig. 2 illustrates an example of a configuration of a device performing communication in a wireless communication system. That is, the configuration illustrated in Fig. 2 can be understood as the configuration of a receiving terminal (120). Terms such as "...unit" and "...unit" used hereinafter refer to a unit that processes at least one function or operation, and this can be implemented using hardware, software, or a combination of hardware and software.

[0059] Referring to FIG. 2, the device may include a communication unit (210), a storage unit (220), and a control unit (230).

[0060] The communication unit (210) can perform functions for transmitting and receiving signals via a wireless channel. For example, the communication unit 210 can perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the communication unit (210) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the communication unit (210) can restore a reception bit stream by demodulating and decoding a baseband signal. In addition, the communication unit (210) can up-convert a baseband signal into an RF (radio frequency) band signal and transmit it through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal.

[0061] To this end, the communication unit (210) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In addition, the communication unit (210) may include a plurality of transmission and reception paths. Furthermore, the communication unit (210) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit (210) may be composed of a digital unit and an analog unit, and the analog unit may be composed of a plurality of sub-units according to operating power, operating frequency, etc. In addition, the communication unit (210) may include a decoding unit to perform decoding according to embodiments of the present disclosure.

[0062] The communication unit (210) transmits and receives signals as described above. Accordingly, the communication unit (210) may be referred to as a “transmitter,” a “receiver,” or a “transceiver.” In addition, in the following description, transmission and reception performed through a wireless channel are used to mean that processing as described above is performed by the communication unit (210). In addition, when the device of FIG. 2 is a base station, the communication unit (210) may further include a backhaul communication unit for communication with other network entities connected through a backhaul network. For example, the communication unit 210 may include at least one transceiver configured to transmit or receive signals.

[0063] The storage unit (220) can store data such as basic programs, application programs, and setting information for the operation of the receiver (120). The storage unit (220) can be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. In addition, the storage unit (220) can provide stored data upon request from the control unit (230).

[0064] The control unit (230) can control the overall operations of the device (e.g., the receiver (120)). For example, the control unit (230) can transmit and receive signals through the communication unit (210). In addition, the control unit (230) can record or read data in the storage unit (220). The control unit (230) can perform functions of a protocol stack required by a communication standard. To this end, the control unit (230) can include at least one processor or microprocessor, or can be a part of a processor. According to various embodiments, the control unit (230) can control the device to perform operations according to various embodiments described below.

[0065] The configuration of the receiver (120) illustrated in FIG. 2 is merely an example, and the implementation examples of devices performing embodiments of the present disclosure are not limited to the configuration illustrated in FIG. 2. In some embodiments, some configurations may be added, deleted, or changed.

[0066] In detailing the present disclosure, commonly used mathematical symbols will be used to avoid ambiguity. These mathematical symbols will be readily understandable to those skilled in the art to which the present disclosure pertains. Representative examples of commonly known mathematical symbols used in the present disclosure include the following:

[0067]

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[0070]

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[0079] Turbo codes and low-density parity-check codes (LDPC codes) are error-correction codes that have performance close to the channel capacity. Because of their excellent performance and characteristics suitable for implementation, turbo codes and LDPC codes are used in various communication and broadcasting systems. For example, turbo codes are used in the 4th generation (4G) of 3GPP. th generation, 4G) LTE (Long-Term Evolution) mobile communication system standard, and LDPC code is adopted and used in the 5th generation (5) of 3GPP. th Generation, 5G) NR (New Radio) mobile communication system standard has been adopted and is being used.

[0080] Below, embodiments of the present invention are described based on a communication or broadcasting system using LDPC codes. However, these are merely examples to avoid redundant descriptions of different channel coding techniques and to simplify the explanation. The various embodiments described can be easily modified and applied to communication systems and / or broadcasting systems that use other channel coding techniques, including turbo codes.

[0081]

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[0087] Figure 4 shows an example of a binary graph corresponding to a parity check matrix.

[0088]

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[0090] LDPC codes are used in various communication and broadcasting systems, and are designed and used to satisfy requirements given according to the characteristics of the system.

[0091] For example, one of the required characteristics of channel codes for communication systems is code length flexibility. In a communication system, the number of information bits to be transmitted can vary with each transmission depending on the message to be transmitted. For example, when transmitting multimedia information such as video, the number of information bits may be large. Conversely, when transmitting text messages, the number of information bits may be small. Furthermore, in a communication system, the amount of communication resources, such as time and frequency, available for the transmission of specific information may vary with each transmission for various reasons. For example, the total amount of available communication resources may change, or the amount of communication resources allocated to transmit a given piece of information from the total available communication resources may change. Since the number of bits to be transmitted varies with each transmission, the channel code used in a communication system must be designed to flexibly handle encoding and decoding in situations where the number of input and output bits of the code change.

[0092] Another desirable characteristic of channel codes for communication systems is rate flexibility. In communication systems, especially mobile communication systems, the channel quality between the transmitter and receiver constantly changes. For example, if the receiver physically moves, the distance between the transmitter and receiver may change, resulting in channel conditions such as path loss and multipath fading. When the channel quality is good, the transmitter can increase the code rate (i.e., reduce the number of parity bits) to efficiently utilize communication resources and achieve error-free encoding / decoding. Conversely, when the channel quality is poor, the transmitter can decrease the code rate (i.e., increase the number of parity bits) to increase the probability of overcoming the poor channel quality. Therefore, channel codes used in communication systems must be designed to flexibly change the code rate according to the situation.

[0093] LDPC codes for practical communication and broadcasting systems are designed to have the above-mentioned required characteristics (flexible code length adjustment, flexible code rate adjustment). For example, LDPC codes that satisfy the above-mentioned required characteristics are designed and used in 3GPP NR mobile communication systems.

[0094] Figure 5 illustrates an example of a series of operations for channel encoding. Hereinafter, a device that performs a series of operations for channel encoding is referred to as a transmitting device. However, the term "transmitting device" is only intended to refer to a device that performs signal processing for signal transmission, and the term is not interpreted to exclude receiving signals from other devices.

[0095] Referring to FIG. 5, the transmitting device (500) may perform segmentation (510), outer encoding (520), zero-filling (530), LDPC encoding (540), code rate adjustment (550), interleaving (560), concatenation (570), and / or modulation (580) to transmit an input bit sequence by LDPC encoding and modulation. The components illustrated in FIG. 5 are components that perform encoding and modulation on the input bit sequence, and this is only an example, and in some cases, some of the components illustrated in FIG. 5 may be omitted or changed, and other components may be added.

[0096] The transmitter (500) determines code parameters to be used for the LDPC code based on given scheduling parameters, such as the number of input bits, the number of final output bits, and the code rate, which is the relationship between them, for encoding and modulation. For example, the code parameters may include at least one of a parity check matrix of the LDPC code to be used, information about the parity check matrix, information for segmentation, information for code rate adjustment (e.g., shortening, puncturing, repetition, etc.), information for bit interleaving, and / or information for modulation.

[0097] The information bits that the transmitting device (500) intends to transmit may be referred to as a transport block (TB). Accordingly, the number of bits in a transport block may be referred to as a transport block size (TBS). The transport block may be a result obtained by encoding with an external concatenation code, such as a cyclic redundancy check (CRC) code.

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[0108] Length generated by the above code rate adjustment The bit sequence of may be transmitted through a bit interleaved coded modulation (BICM) technique, and in this case, the transmitting device (500) may perform interleaving (560) to appropriately map the bits to the modulation symbols. Interleaving may be performed on the bit sequence whose code rate is adjusted.

[0109] If the transmission block is segmented into two or more code blocks through segmentation (510), the transmitting device (500) can perform concatenation (570). The outputs of the series of encoding processes for each code block can be combined into one. Here, the individual results of the code blocks can be simply sequentially concatenated, or the results of the code blocks can be mixed and concatenated according to a predetermined pattern.

[0110] The transmitter (500) may perform bit-unit operations (e.g., segmentation (510), outer encoding (520), zero-filling (530), LDPC encoding (540), code rate adjustment (550), interleaving (560), and concatenation (570)) and then perform modulation (580). Baseband signals to be transmitted (hereinafter, baseband signals) may be generated through modulation (580). The modulation method of modulation (580) may be, for example, BPSK (binary phase shift keying). -BPSK, QPSK (quadrature phase shift keying), 16-QAM (quadrature amplitude modulation), 64-QAM, 256-QAM, or 1024QAM may be used, and any other modulation technique may be applied to transmit the signal. As a non-limiting example, various additional operations may be performed before, after, or within the modulation (580) to enable the receiving device to effectively demodulate and restore the signal, which will be described later. The baseband signals may be transmitted on a carrier of the band to be used for transmission. Through the above series of operations, the bits of the transmission block are encoded and modulated and then transmitted.

[0111] Although functional configurations for LDPC encoding (e.g., LDPC encoding (540)) are described in FIG. 5, the transmitting device (500) may further include configurations for controlling the operation of the transmitting device in some cases.

[0112] According to one embodiment, the transmitting device (500) may additionally include a communication unit. The communication unit performs functions for transmitting and receiving signals via a wireless channel. For example, the communication unit performs baseband signal and bit-to-bit conversion functions according to the physical layer specifications of the system. For example, when transmitting data, the communication unit generates complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the communication unit restores the reception bit stream by demodulating and decoding the baseband signal. In addition, the communication unit up-converts the baseband signal into an RF (radio frequency) band signal and transmits it through an antenna, and down-converts the RF band signal received through the antenna into a baseband signal. According to various embodiments, the transmitting device (500) may transmit an LDPC encoded signal to a receiving device (600) described below.

[0113] To this end, the communication unit may include a transmitting filter, a receiving filter, an amplifier, a mixer, an oscillator, a digital-to-analog converter (DAC), an analog-to-digital converter (ADC), etc. In addition, the communication unit may include a plurality of transmitting and receiving paths. Furthermore, the communication unit may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit may be composed of a digital unit and an analog unit, and the analog unit may be composed of a plurality of sub-units according to operating power, operating frequency, etc.

[0114] Figure 6 illustrates an example of a series of operations for channel decoding. Hereinafter, a device that performs the series of operations for channel decoding is referred to as a receiving device. However, the term "receiving device" is only intended to refer to a device that performs signal processing for signal transmission, and the term is not interpreted to exclude transmitting signals to other devices.

[0115] Referring to FIG. 6, the receiving device (600) may perform demodulation (610), de-concatenation (620), deinterleaving (630), code rate de-adjustment (640), HARQ soft-combining (650), LDPC decoding (660), zero removal (670), outer decoding (680), and / or de-segmentation (690) to estimate accurate information bits from the received signal.

[0116] The receiving device (600), like the transmitting device (500), checks or determines various parameters necessary for the receiving operation based on scheduling information, code parameters, etc. The following series of processes performed by the receiver are performed based on the various parameters checked and determined in this manner.

[0117] The receiving device (600) can perform demodulation (610). Demodulation (610) may include several processes depending on the case. For example, demodulation (610) may be subdivided into a process of obtaining a channel estimation result based on a received signal and a soft demapping process of determining values ​​(e.g., log-likelihood ratio (LLR) or indices having equivalent technical meaning) required for FEC (forward error control) decoding corresponding to the codeword bits transmitted from the demodulated signal or symbol based on the channel estimation result. In this case, each demodulation operation may be subdivided into each channel measurement block, soft demapping block, etc. Of course, further subdivision is possible depending on the structure of the system.

[0118] From now on, operations are described assuming a receiving device (600) that calculates and processes LLR values ​​for codeword bits. However, the metric value used by the receiving device to process a signal is not limited to LLR, and any value equivalent thereto may be used.

[0119]

[0120]

[0121]

[0122] For example, when rate adjustment using a circular buffer is performed in a 3GPP NR LDPC encoding system, the receiving device (600) can generate an LLR sequence for the parent code by performing rate inverse adjustment (640) through the following process.

[0123]

[0124]

[0125]

[0126]

[0127]

[0128]

[0129]

[0130]

[0131]

[0132]

[0133]

[0134]

[0135]

[0136]

[0137]

[0138] In mobile communication systems, HARQ operations can be performed to ensure data integrity and efficiently utilize overall communication transmission resources. In this case, the receiving device transmits the HARQ LLR sequence for each code block. It operates using separate memory, etc.

[0139]

[0140]

[0141]

[0142] If there is no HARQ operation of the receiving device (600), HARQ soft-combining (670) can be omitted.

[0143]

[0144]

[0145]

[0146] The estimated bit sequence for the code block obtained after LDPC decoding may include shortened bits without a fixed amount of information due to zero filling (530) performed in the transmitting device (500). Therefore, the receiving device (600) may perform zero removal (670) to exclude the shortened bits from the estimated bit sequence as a reverse process of the zero filling (530) performed in the transmitting device (500).

[0147] The receiving device (600) can perform external decoding (680). If external encoding (520) is performed on the code block, the bit sequence obtained as a result of LDPC decoding can be decoded based on the external encoding. As a non-limiting example, if an error detection code such as a CRC code is concatenated, the receiving device (600) can additionally check the validity of the bit sequence obtained by LDPC decoding.

[0148] If a transmission block is composed of multiple code blocks, inverse segmentation (690) may be performed to derive a final result by concatenating the results of each code block. This process may be understood as the reverse process of segmentation (510) performed in the transmitting device (500).

[0149] The components illustrated in the above drawing 6 are components that perform functions corresponding to the components illustrated in the drawing 6, and this is only an example, and some of them may be omitted or changed depending on the case, and other components may be added.

[0150]

[0151]

[0152]

[0153]

[0154]

[0155] In other embodiments, LLR may be defined differently. For example, the numerator and denominator may be switched in the fractional value taking the log of Equation 3. Such LLR is simply a case of switching the signs of the defined LLR as in Equation 3 (i.e., changing + to - and - to +). Although the present disclosure describes the operation of the invention by considering the LLR defined as in Equation 3, the invention may be applied without any difference if the sign is switched even if the LLR is defined differently.

[0156]

[0157] The process of setting the LLR values ​​for the shortened codeword bits and the punctured codeword bits through the code rate de-adjustment (640) in the receiving device (600) is based on the reliability expressed as the absolute value of the LLR. The receiving device (600) does not receive the shortened bits, but can clearly know that the value is 0. Therefore, the LLR value for the shortened bits can be set to a positive value greater than a certain value (e.g., a positive infinite value) to indicate that the bit value is 0 and that the certainty or reliability thereof is high. In an actual implementation, it can be set to any positive number that the data type used in the receiving device (600) can express. On the other hand, since the receiving device (600) cannot know any information about the punctured bits, the LLR value for the shortened bits is determined to be 0. An LLR value of 0 means that the probability of the two values ​​that the codeword bits can have is equal to 0.5.

[0158]

[0159] LDPC decoding (660) can be performed through repeated belief propagation based on the intrinsic LLR sequence as described above. Hereinafter, an example of belief propagation decoding of an LDPC code is described. The structure and architecture of the decoder, the algorithm used, etc. can be configured in various ways, and the scope of application of the embodiments of the present invention is not limited to a specific implementation method below. The embodiments of the present disclosure can be applied to various decoding architectures and algorithms, and such application methods will be clearly understood by those skilled in the art to which the present disclosure pertains.

[0160]

[0161]

[0162]

[0163]

[0164]

[0165] The AP-LLR sequence set as above is updated at each iteration by the repeated belief-propagation operation of LDPC decoding. This process can be understood as a message passing operation between a variable node (hereinafter VN) and a check node (hereinafter CN) on a bipartite graph corresponding to a parity check matrix (or sub-parity check matrix).

[0166]

[0167]

[0168]

[0169]

[0170]

[0171]

[0172] The C2V message calculation by the above mathematical expression 7 can be approximated and transformed in various ways. In one embodiment, the C2V message calculation as in the above mathematical expression 7 can be calculated as in the following mathematical expression 8 using the so-called min-sum approximation method.

[0173]

[0174]

[0175]

[0176]

[0177]

[0178]

[0179]

[0180]

[0181]

[0182]

[0183]

[0184]

[0185] Syndrome screening It performs a syndrome check on all elements of the estimated codeword vector. However, since what is of interest from the perspective of the receiving device (600) are the information bits included in the estimated codeword vector, the receiving device (600) can determine the validity of the decoding result by utilizing only some of the syndrome check formulas without using the entire estimated codeword vector.

[0186]

[0187] The above series of processes reflects all possible guesses about low-confidence bits into the decoder input, and then expects that iterative belief-propagation decoding will succeed for the input that reflects the correct guess among them. This opportunistic decoding operation is called by various names, such as ensemble decoding, quasi maximum-likelihood (quasi-ML, QML) decoding, afterburner decoding, saturate decoding, and / or equivalent technical terms. Hereinafter, in the present disclosure, this technique is referred to as ensemble decoding and embodiments are described.

[0188] Figure 7 illustrates an example of the ensemble decoding process. Figure 7 conceptually illustrates the process of an ensemble decoding technique, which estimates a low-confidence LLR using all possible methods, as described above, and then trust-propagates the result to verify its validity.

[0189]

[0190] The candidate LLR sequences modified as described above can be independently decoded. As discussed above, the decoding of LDPC codes is performed through a trust-propagation process based on intrinsic LLR sequences. Since the modified candidate LLR sequences are generated with all possible combinations of codeword bits, it is clear that one of them corresponds to the correct codeword bit. Therefore, the modified candidate LLR sequence, whose LLR absolute value is changed to the maximum or highest value for the correct codeword bit, transmits the correct message to other codewords through the iterative message exchange decoding operation, thereby increasing the probability of successful decoding. Therefore, After performing each decoding based on the modified candidate LLR sequence for the dog, a syndrome check, a check using the concatenated CRC code, etc. are performed, and if the decoding is successfully completed, the estimate obtained by the decoding can be regarded as the result of the final successful decoding. In this way, the decoder for ensemble decoding can increase the probability of successful decoding and improve error-correction performance by performing multiple decodings based on a plurality of modified candidate LLR sequences and combining the results.

[0191] Figure 8 is a block diagram for ensemble decoding. A component for LDPC decoding (660) in a decoder (e.g., a receiving device (600)) can perform ensemble decoding.

[0192]

[0193] Below, based on various examples, we propose a method for improving an ensemble decoding method and device. Conventional ensemble decoding methods determine the location of an LLR to be modified by aligning elements of an intrinsic LLR sequence. This disclosure identifies the following problems or areas for improvement in conventional methods.

[0194] - Conventional ensemble decoding methods and devices identify the locations of LLRs whose values ​​will change based on the intrinsic LLR sequence. While this method appears reasonable, it may not guarantee an improvement in the final decoding result.

[0195] - Conventional ensemble decoding methods and devices perform an operation that compares the absolute values ​​of all LLRs to determine the location of the LLR whose value will be changed. This operation, which is not performed in conventional decoding, causes additional complexity and delay.

[0196] Embodiments of the present invention improve upon the problems of conventional ensemble decoding methods and devices based on the structure and characteristics of LDPC codes. Various embodiments of the present invention are introduced below.

[0197] An ensemble decoding method and device according to one embodiment of the present invention is characterized in that, when determining an LLR position for which a value is to be changed based on a given intrinsic LLR sequence, the search range of the LLR to be changed is limited to information bits (or information bits and shortened bits), or to some area that is judged to be helpful for trust-propagation decoding.

[0198] Figure 9 shows an example of a search range for the position of the LLR to be changed in ensemble decoding.

[0199] Figure 10 shows an example of a limitation on the position of the LLR to be changed in ensemble decoding.

[0200]

[0201]

[0202] The reason why the information bit range excluding the puncturing and shortening bits in the embodiment of the present invention is determined as the search range of the LLR whose value is to be changed is because a general LDPC code is designed to prioritize improvement of information bits over parity bits. For example, the 3GPP NR LDPC code is designed with the goal of error correction and recovery for information bits, and accordingly, it is designed so that the VNs corresponding to the information bits receive messages from more neighboring CNs. In other words, the LDPC code is designed so that the VNs corresponding to the information bits have a high degree. If the absolute value of the information bit LLR corresponding to a VN having a high degree is large, it can have a more positive effect on other bits in repetitive message exchange by reliable propagation. The decoder according to the embodiment of the present disclosure can determine the search range to change the LLR value of the information bit corresponding to a VN having a high degree.

[0203]

[0204]

[0205] FIG. 12 illustrates an example of a limitation on the positions of LLRs to be changed for ensemble decoding in an intrinsic LLR sequence that does not include a systematic puncture bit. FIG. 12 specifically illustrates a search range of LLRs whose values ​​can be changed based on an intrinsic LLR sequence according to embodiments of the present disclosure when the intrinsic LLR sequence does not include an LLR for a systematic puncture bit.

[0206]

[0207]

[0208]

[0209]

[0210] Figure 14 illustrates an example of performance according to restrictions on the positions of LLRs to be changed for ensemble decoding. Figure 14 illustrates the results of evaluating the error-correction performance of a conventional method (e.g., method 1) and a method (e.g., method 2) using restrictions on the positions of LLRs to be changed according to embodiments of the present disclosure, depending on the code dimension and code rate in a 5G NR LDPC code system.

[0211]

[0212]

[0213]

[0214] In other words, the first method and the second method are the same in that they generate candidate LLR sequences transformed through all possible patterns (the values ​​at each position are divided into 0 and 1 to represent combinations of possible cases) at the position where the LLR value is changed, and obtain the final decoding result through decoding for each candidate LLR sequence (in other words, ensemble decoding). In other words, the first method and the second method differ in that they set different search ranges for finding LLR positions to be changed for ensemble decoding. For reference, the graph (1400) also includes the result of normal decoding (normal BP) without applying ensemble decoding.

[0215] As illustrated in FIG. 14, the decoder according to embodiments of the present disclosure can provide almost the same error-correction performance with low complexity by considering a relatively small search range rather than considering the entire range of bits transmitted through a wireless channel (e.g., bits according to code rate adjustment) (or an area including shortened bits by zero filling (530) in addition to the entire range of transmitted bits). As confirmed through the graph (1300) of FIG. 13 and the graph (1400) of FIG. 14, according to one embodiment, the lifting size (e.g., Z) for LDPC and the number of bits to be encoded in a code block (e.g., K or K bBy limiting the search range according to Z), the same error-correction performance can be achieved with a smaller number of operations. For example, the decoder can determine the search range based on the lifting size and the number of bits to be encoded. For example, the size of the search range can be a value obtained by subtracting twice the lifting size from the number of bits to be encoded. This is because twice the lifting size is punctured in the systematic part of the encoding region (e.g., N). A specified number of change regions (i.e., positions where the LLR value is to be changed) can be determined within the search range. For example, the change regions can be determined as positions corresponding to the upper p bits having a lower absolute value of the LLR value among the bits in the search range.

[0216] Fig. 15 is a block diagram for limiting the position of an LLR to be changed according to a post-LLR sequence. The ensemble decoding method and device according to one embodiment of the present disclosure determines the position of the LLR to be changed based on the AP-LLR sequence finally obtained when decoding fails after attempting decoding based on a given intrinsic LLR sequence. In other words, the search range (or the position of the LLR to be changed for ensemble decoding) mentioned through Figs. 8 to 14 can be limited based on the obtained AP-LLR sequence. The decoder performs decoding based on the intrinsic LLR sequence, and determines which position of the LLR ultimately failed to converge and thus caused the decoding to fail through the decoding result, thereby performing pre-compensation. In the above embodiment, decoding performance can be improved by changing the LLR that ultimately contributes to the decoding failure.

[0217] Referring to Fig. 15, a general decoding (1510) can be performed on a given intrinsic LLR sequence (1501). If the decoding (1510) is successful, the result obtained from the decoder is output as the final result (1503). If the decoding (1510) fails, the decoder can obtain an updated AP-LLR (1502) through iterative trust-propagation decoding.

[0218]

[0219] According to embodiments of the present disclosure, a decoder selects the position of an LLR whose value is to be changed based on an updated AP-LLR sequence after performing repeated belief propagation for a preset maximum number of repeated decoding iterations, and this part is differentiated from the conventional method (i.e., the first method). This method may be referred to as the third method in the present disclosure. According to embodiments of the present disclosure, even if the position of an LLR whose value is to be changed is determined based on the AP-LLR sequence, modified candidate LLR sequences are generated by changing the corresponding position element of the intrinsic LLR sequence (1501). In other words, the modified candidate LLR sequences can be generated by replacing the value of each position of a change region with candidate values ​​(e.g., an LLR value corresponding to 0, an LLR value corresponding to 1) based on the intrinsic LLR sequence (1501). In terms of the LLR sequence input for decoding according to trust-propagation, the intrinsic LLR sequence (1501) may be referred to as a first input sequence, and the transformed candidate LLR sequences may be referred to as second candidate input sequences.

[0220] In the method for determining the position of an LLR whose value is to be changed based on an AP-LLR sequence according to embodiments of the present disclosure (i.e., the third method), the search range of the AP-LLR sequence can be determined by a method different from the first method. In the conventional method, the intrinsic LLR sequence used as a search target includes an LLR (value 0) for a punctured bit, which is not considered as the position of the LLR whose value is to be changed. However, the third method according to embodiments of the present disclosure is based on the AP-LLR sequence obtained after decoding. The AP-LLR for the punctured bit among all encoded bits can be updated by an iterative trust-propagation operation.

[0221] Due to the above update, unlike the LLR position selection method based on the intrinsic LLR sequence (1501), the punctured bits can be understood as positions that can significantly affect the actual decoding performance. In the third method, the punctured bits can also be considered as positions where the value of the LLR can be changed. According to the third method, the punctured bits considered as positions where the value can be changed for ensemble decoding can include systematic punctured bits (e.g., information bits) and general punctured bits (e.g., parity bits). Examples of FIG. 16 are described for explanation of the punctured bits.

[0222] Figure 16 illustrates examples of restrictions on the location of LLRs to be changed according to the post-LLR sequence. Figure 16 illustrates examples of search ranges according to the third method.

[0223] Referring to Fig. 16, an AP-LLR sequence (e.g., an AP-LLR sequence (1502)) can be largely divided into a systematic part (e.g., a part for information bits) and a parity part. The systematic part can be further divided into a systematic puncturing part, a shortening part, and a remainder part. The parity part can be divided into a part in which the LLR is updated by iterative decoding and a part in which it is not. The AP-LLR sequence can be a result of decoding performed according to trust propagation. Decoding according to trust propagation can include a VN update and a CN update. The probability update according to the VN update and the CN update can be performed according to the above-described [Mathematical Formula 6] to [Mathematical Formula 12]. The length of the AP-LLR sequence is equal to N, which is the length of the parent code vector for the LDPC code. The above AP-LLR sequence can be divided into a systematic part (e.g., a part for information bits) and a parity part. Depending on the lifting size set for the LDPC code, some bits among the bits of the entire code length N are punctured. The punctured bits are set to have an LLR value corresponding to '0', but variable nodes corresponding to the punctured bits can be updated through the reliable-propagation decoding. Due to the above update, the LLR of the variable node corresponding to at least one of the punctured bits may no longer be fixed. In other words, the LLR for some or all of the punctured bits can be updated by an iterative reliable-propagation decoding operation. Since the bits punctured in the systematic part are for information bits, restoration of the information bit part must be necessarily performed, and therefore the AP-LLR of the corresponding part can be necessarily updated.

[0224] Referring to the first example (1610), the decoder can determine the position of the LLR to be changed by using the entire range of LLRs in which the AP-LLR is updated as a search range. The entire range in which the AP-LLR is updated corresponds to the entire systematic part and the area excluding the punctured part in the parity part. The search range may include the systematic punctured bits, the remaining systematic bits, the parity bits in which the AP-LLR is updated, and the shortened bits. In the first example (1610), the change area is illustrated as including the area of ​​the shortened bits according to zero filling (e.g., zero filling (530)), but embodiments of the present disclosure are not limited thereto. The AP-LLR for the shortened bits generally does not affect determining the position of the LLR to be changed. As a non-limiting example, the search range, i.e., the change area, may not include the area of ​​the shortened bits according to zero filling (e.g., zero filling (530)).

[0225] Referring to the second example (1620), the decoder can determine the position of the LLR to be changed by using the LLR of the systematic range in which the AP-LLR is updated as a search range. This search range can include the systematic puncturing bits, the remaining systematic bits, and the shortened bits. In other words, unlike the first example (1610), the decoder according to the second example (1620) can exclude the area corresponding to the parity bits in which the AP-LLR is updated from the search range for ensemble decoding. In the second example (1620), the search range is illustrated as including the area of ​​the shortened bits according to zero filling (e.g., zero filling (530)), but embodiments of the present disclosure are not limited thereto. The AP-LLR for the shortened bits generally does not affect the determination of the position of the LLR to be changed. As a non-limiting example, the search range, i.e., the search range, may not include the area of ​​shortened bits due to zero filling (e.g., zero filling (530)).

[0226] Referring to the third example (1630), the decoder can determine the position of the LLR whose value is to be changed by using the LLR for the systematic puncturing bit for which the AP-LLR is updated as a search range. This search range may include all or part of the systematic puncturing bits. For example, the 3GPP NR LDPC code is designed to effectively restore the systematic puncturing bits, and accordingly, the VNs corresponding to the systematic puncturing bits are designed to receive messages from more neighboring CNs. That is, the LDPC code is designed such that the VNs corresponding to the systematic puncturing bits have a high degree. If the absolute value of the LLR of the information bit corresponding to the VN having a high degree is large, it can have a more positive effect on other bits in the repetitive message exchange by reliable propagation. The above embodiment of the present disclosure determines the search range to change the LLR value of the information bit corresponding to the VN having a high degree based on this basis. According to one embodiment, the decoder may determine at least some of the systematic puncturing bits as a change region for ensemble decoding. For example, the decoder may identify at least one VN among variable nodes corresponding to the systematic puncturing bits according to a degree of a base graph for an LDPC code. For example, the decoder may identify the top X VNs when sorted based on the degree. As another example, the decoder may identify VNs having a degree greater than or equal to a threshold value. The decoder may determine a bit position corresponding to the identified VN as a decoding region for the ensemble decoding.

[0227] Fig. 17 illustrates an example of the performance of restricting the positions of LLRs to be changed according to the post-LLR sequence. Fig. 17 shows the results of evaluating the error-correction performance of a conventional method (e.g., method 1) and a method (e.g., method 3) that uses restrictions on the positions of LLRs to be changed using AP-LLR according to embodiments of the present disclosure, depending on the code dimension and code rate in a 5G NR LDPC code system.

[0228]

[0229] As illustrated in FIG. 17, it can be confirmed that almost similar error-correction performance is achieved for various code dimensions and code rates even though the search ranges are set differently according to examples of the third method (e.g., the first example (1610), the second example (1620), and the third example (1630)). Since the search range of the third example (1630) is the narrowest, ensemble decoding according to the third example (1630) may be advantageous for implementation in terms of providing the same and / or similar performance with low complexity.

[0230] Figure 18 illustrates an example of the performance of limiting the position of an LLR to be changed according to a post-LLR sequence. Figure 18 illustrates an evaluation of the error-correction performance of two embodiments of the present disclosure that determine the position of an LLR to be changed based on intrinsic LLR and AP-LLR in a 5G NR LDPC code system.

[0231]

[0232]

[0233] As illustrated in FIG. 18, it can be confirmed that the method for determining a change area based on AP-LLR according to embodiments of the present disclosure achieves better performance (i.e., a lower curve in FIG. 18) than the method for determining a change area based on intrinsic LLR. However, the method for determining the position of an LLR to be changed based on AP-LLR (e.g., the third method) may have higher complexity and delay than the method based on intrinsic LLR (e.g., the second method) because it performs one-time decoding based on intrinsic LLR. Therefore, one of the two methods can be effectively selected depending on the conditions, environment, and requirements of the LDPC code system.

[0234] Figure 19 illustrates an example of the performance of limiting the position of an LLR to be changed according to a post-LLR sequence. Figure 19 illustrates an evaluation of the error-correction performance of two embodiments of the present invention that determine the position of an LLR to be changed based on intrinsic LLR and AP-LLR in a 4G LTE turbo code system.

[0235]

[0236]

[0237] As illustrated in FIG. 19, it can be confirmed that the method for determining a change area based on AP-LLR according to embodiments of the present disclosure achieves better performance (i.e., a lower curve in FIG. 19) than the method for determining a change area based on intrinsic LLR. However, the method for determining the position of an LLR to be changed based on AP-LLR (e.g., the third method) may have higher complexity and delay than the method based on intrinsic LLR (e.g., the second method) because it performs one-time decoding based on intrinsic LLR. Therefore, one of the two methods can be effectively selected depending on the conditions, environment, and requirements of the turbo code system.

[0238] FIG. 20 and FIG. 21 are block diagrams for ensemble decoding using signal expansion. The span decoding method and device according to one embodiment of the present disclosure performs decoding by adding a virtual LLR value to the punctured bit position of a given intrinsic LLR sequence. That is, the present embodiment performs decoding at a changed position in an area separated by the same distance due to the virtual signal based on the received signal. In this case, the range to which the signal is added can be selected to include bits punctured in the systematic (e.g., information bits) or bits punctured in the parity. This method (hereinafter, the fourth method) ultimately provides the effect of lowering the code rate as the parity bit of the given signal is virtually expanded, which means improved decoding performance compared to the existing method.

[0239] Referring to Fig. 20, a general decoding (2010) is performed on a given intrinsic LLR sequence (2001). If the decoding (2010) is successful, the estimate obtained from the decoder is output as the final result (2002). Although not shown in Fig. 20, if the decoding (2010) fails, the intrinsic LLR sequence (2001) can be used for virtual expansion (2020). The decoder virtually adds LLR values ​​at the punctured bit positions of the given signal. At this time, the positions where the values ​​are changed may reflect the structural characteristics of the code or may be selected arbitrarily, rather than using the intrinsic LLR values ​​of the given signal and the values ​​calculated by the decoding.

[0240] Referring to FIG. 21, unlike FIG. 20, instead of performing general decoding, the decoder can perform virtual expansion (2020) directly from a given LLR sequence (e.g., intrinsic LLR sequence (2101)). The decoder can virtually add an LLR value to at least one of the punctured bits of the given LLR sequence (e.g., intrinsic LLR sequence (2101)). The decoder according to embodiments of the present disclosure can utilize either the method according to FIG. 20 or the method according to FIG. 21.

[0241]

[0242] A decoder according to an embodiment of the fourth method can select a location to add an LLR value based on the locations of puncture bits of a given LLR sequence (e.g., an intrinsic LLR sequence (2001)). The fourth method may be understood as not limiting a location to change an LLR value for ensemble decoding within the given LLR sequence, but rather finding a location to additionally generate a candidate pattern for ensemble decoding, in addition to the given LLR sequence.

[0243]

[0244]

[0245] In the embodiment of the present disclosure, the process of selecting a location to change a value using intrinsic or AP LLR is omitted, so that the implementation and realization process is simplified, and thus the implementation complexity and delay due to decoding can be reduced.

[0246] Figures 22 to 25 illustrate examples of ensemble decoding using signal expansion. Figures 22 to 25 illustrate areas where LLR values ​​will change according to the fourth method.

[0247]

[0248]

[0249] represents the bit index of the i-th position within the change area. N b Z can correspond to the code length N. Z can correspond to the lifting size for LDPC. E represents the number of bits according to the code rate adjustment (e.g., the number of bits transmitted over a wireless channel), and F represents the number of bits shortened according to zero filling (e.g., zero filling (530)). q represents the size of the change region.

[0250]

[0251]

[0252] represents the bit index of the i-th position within the change area. N b Z can correspond to the code length N. Z can correspond to the lifting size for LDPC. E represents the number of bits according to the code rate adjustment (e.g., the number of bits transmitted over a wireless channel), and F represents the number of bits shortened according to zero filling (e.g., zero filling (530)). q represents the size of the change region.

[0253] In Figs. 24 and 25, the search range of LLRs whose values ​​can be changed is specifically illustrated when an LLR for a systematic puncture bit is not included in a given intrinsic LLR sequence. Fig. 24 has the same parity part operation as Fig. 22, but since there is no systematic puncture bit, in this case, the change range of the LLR can be determined according to Equation 15.

[0254]

[0255] represents the bit index of the i-th position within the change area. N b Z can correspond to the code length N. Z can correspond to the lifting size for LDPC. E represents the number of bits according to the code rate adjustment (e.g., the number of bits transmitted over a wireless channel), and F represents the number of bits shortened according to zero filling (e.g., zero filling (530)). q represents the size of the change region.

[0256] Fig. 25 is a case where the systematic puncture bit and the punctured entire parity bit are not included, and the LLR change range can be determined according to mathematical expression 16.

[0257]

[0258] represents the bit index of the i-th position within the change area. N b Z can correspond to the code length N. Z can correspond to the lifting size for LDPC. E represents the number of bits according to the code rate adjustment (e.g., the number of bits transmitted over a wireless channel), and F represents the number of bits shortened according to zero filling (e.g., zero filling (530)). q represents the size of the change region.

[0259] Figure 26 illustrates an example of the performance of ensemble decoding using signal expansion. Figure 26 illustrates an evaluation of the error-correction performance of the above embodiment of the present invention and a method for determining the position of an LLR whose value is to be changed based on the previously proposed AP-LLR sequence according to the code dimension and code rate in a 5G NR LDPC code system.

[0260]

[0261]

[0262] As illustrated in FIG. 26, it can be confirmed that the method of considering a small search range by the fourth method achieves error-correction performance similar to the method of considering a search range by using the AP-LLR sequence by the third method. That is, although the decoding performance is similar, since there is no comparison operation of LLR values ​​for determining a change area, the fourth method may be advantageous in terms of shortening the delay time due to decoding and reducing implementation complexity.

[0263] Figure 27 shows an example of a wireless communication system.

[0264] Referring to FIG. 27, FIG. 27 illustrates a base station (2710) and a terminal (2720) as some of the nodes utilizing a wireless channel in a wireless communication system. Although FIG. 27 illustrates only one base station, the wireless communication system may further include other base stations identical or similar to the base station (2710). For example, the base station (2710) may correspond to a transmitting device (500), and the terminal (2720) may correspond to a receiving device (600). In another example, the base station (2710) may correspond to a receiving device (600), and the terminal (2720) may correspond to a transmitting device (500).

[0265] The base station (2710) is a network infrastructure that provides wireless access to the terminal (2720). The base station (2710) has coverage defined based on the distance at which a signal can be transmitted. In addition to the base station, the base station (2710) includes an 'access point (AP)', a 'radio access network (RAN) node', an 'eNodeB (eNB)', and a '5G node (5 th The term "network node" may be referred to as "next generation node (gNB)", "wireless point", "transmission / reception point (TRP)", "communication node", "wireless communication device", "wireless communication equipment", "network node", "network entity", or other terms having equivalent technical meaning.

[0266] The terminal (2720) is a device used by a user and communicates with the base station (2710) via a wireless channel. The link from the base station (2710) to the terminal (2720) is referred to as a downlink (DL), and the link from the terminal (2720) to the base station (2710) is referred to as an uplink (UL). In addition, although not shown in FIG. 27, the terminal (2720) and another terminal may communicate with each other via a wireless channel. In this case, the link between the terminal (2720) and another terminal (device-to-device link, D2D) is referred to as a sidelink, and the sidelink may be used interchangeably with the PC5 interface. In some other embodiments, the terminal (2720) may be operated without the intervention of a user. In one embodiment, the terminal (2720) is a device that performs machine type communication (MTC) and may not be carried by the user. Additionally, according to one embodiment, the terminal (2720) may be an NB (narrowband)-IoT (internet of things) device.

[0267] The terminal (2720) may be referred to as a terminal, or other terms such as 'user equipment (UE),' 'customer premises equipment (CPE),' 'mobile station,' 'subscriber station,' 'remote terminal,' 'wireless terminal,' 'electronic device,' or 'user device,' or other terms having equivalent technical meanings.

[0268] The base station (2710) can perform beamforming with the terminal (2720). The base station (2710) and the terminal (2720) can transmit and receive wireless signals in a relatively low frequency band (e.g., frequency range 1 (FR 1) of NR). In addition, the base station (2710) and the terminal (2720) can transmit and receive wireless signals in a relatively high frequency band (e.g., FR 2 (or, FR 2-1, FR 2-2, FR 2-3), FR 3 of NR), millimeter wave (mmWave) band (e.g., 26 GHz, 28 GHz, 30 GHz, 38 GHz, 60 GHz)). To improve channel gain, the base station (2710) and the terminal (2720) can perform beamforming. Here, the beamforming can include transmission beamforming and reception beamforming. The base station (2710) and the terminal (2720) can assign directionality to transmitted or received signals. To this end, the base station (2710) and the terminal (2720) can select serving beams through beam search or beam management procedures. After the serving beams are selected, subsequent communications can be performed through resources that have a QCL relationship with the resources that transmitted the serving beams.

[0269] If large-scale characteristics of a channel carrying a symbol on a first antenna port can be inferred from a channel carrying a symbol on a second antenna port, the first antenna port and the second antenna port can be evaluated to have a QCL relationship. For example, the large-scale characteristics may include at least one of delay spread, Doppler spread, Doppler shift, average gain, average delay, and a spatial receiver parameter.

[0270] Although both the base station (2710) and the terminal (2720) are described as performing beamforming in FIG. 27, the embodiments of the present disclosure are not necessarily limited thereto. In some embodiments, the terminal may or may not perform beamforming. Furthermore, the base station may or may not perform beamforming. That is, either only one of the base station and the terminal may perform beamforming, or neither the base station nor the terminal may perform beamforming.

[0271] Fig. 28 illustrates network entities according to a distributed arrangement. For example, the network entities may include a digital unit (DU) and a radio unit (RU) (2820) (or a massive multiple input multiple output (MMU) unit). For example, the network entities may be connected via a fronthaul. Unlike the backhaul between a base station and a core network, the fronthaul refers to entities (e.g., DU (2810), RU (2820)) between a wireless LAN and a base station. Although Fig. 28 illustrates an example of a fronthaul structure between a DU (2810) and one RU (2820), this is merely for convenience of explanation and the present disclosure is not limited thereto. In other words, embodiments of the present disclosure may also be applied to a fronthaul structure between one DU and multiple RUs. For example, embodiments of the present disclosure may be applied to a fronthaul structure between one DU and two RUs. Additionally, the embodiments of the present disclosure can also be applied to a fronthaul structure between one DU and three RUs.

[0272] Referring to FIG. 28, the base station (2710) may include a DU (2810) and a RU (2820). The fronthaul (2815) between the DU (2810) and the RU (2820) is F xIt can be operated through an interface. For the operation of the fronthaul (2815), for example, an interface such as an enhanced common public radio interface (eCPRI), radio over ethernet (ROE) can be used. Depending on the implementation, in addition to a digital unit (DU), the DU (2810) may be referred to as a baseband unit (BBU), a digital BBU, a baseband digital unit, a digital processing unit, a digital processing circuit, a baseband processing circuit, a baseband processing unit, and / or equivalent technical terms thereof. Depending on the implementation, in addition to a radio unit (RU), the RU (2820) may be referred to as a remote unit, a radio demote head (RRH), a radio processing circuit, a radio processing unit, an antenna integrated radio, an air radio device, an air scale communication device, a radio device, a radio communication device, and / or equivalent technical terms thereof. Also, according to the implementation example, the network entity connected to the DU (2810) in the present disclosure is described as the RU (2810), but it is of course possible for a massive multiple input multiple output (MMU) unit to be connected to the DU (2810) instead of the RU (2810).

[0273] As communication technology advances, mobile data traffic increases, significantly increasing the bandwidth requirements for the fronthaul between the digital unit and the wireless unit. In deployments such as C-RAN (centralized / cloud radio access network), the DU performs functions for the packet data convergence protocol (PDCP), radio link control (RLC), media access control (MAC), and physical (PHY) layers, while the RU can be implemented to perform functions for the PHY layer in addition to the radio frequency (RF) layer. The DU (2810) can be responsible for upper layer functions of the wireless network.

[0274] For example, DU (2810) can perform functions of MAC layer and part of PHY layer. Here, part of PHY layer means functions performed at a higher level among the functions of PHY layer, and may include, for example, channel encoding (or channel decoding), scrambling (or descrambling), modulation (or demodulation), layer mapping (or layer demapping). According to an embodiment, if DU (2810) complies with O-RAN standard, it may be referred to as O-DU (O-RAN DU). DU (2810) may be replaced and expressed as a first network entity for a base station (e.g., gNB) in embodiments of the present disclosure, if necessary. RU (2820) may be in charge of lower layer functions of a wireless network. For example, RU (2820) may perform part of PHY layer and RF functions. Here, a part of the PHY layer refers to functions of the PHY layer that are performed at a relatively lower level than the DU (2810), and may include, for example, iFFT transform (or FFT transform), CP insertion (CP removal), and digital beamforming. The RU (2820) may be referred to as an 'access unit (AU)', an 'access point (AP)', a 'transmission / reception point (TRP)', a 'remote radio head (RRH)', a 'radio unit (RU)', or other terms having equivalent technical meanings thereto. According to an embodiment, when the RU (2820) complies with the O-RAN standard, it may be referred to as an O-RU (O-RAN RU). The RU (2820) may be represented by being replaced with a second network entity for a base station (e.g., gNB) in embodiments of the present disclosure, as needed.

[0275] Although the base station (2710) is described in FIG. 28 as including a DU (2810) and a RU (2820), the embodiments of the present disclosure are not limited thereto. The base station according to the embodiments may be implemented in a distributed deployment according to a centralized unit (CU) configured to perform functions of upper layers of an access network (e.g., packet data convergence protocol (PDCP), radio resource control (RRC)) and a distributed unit (DU) configured to perform functions of lower layers. For example, the digital unit (DU) (2810) may be implemented by separating it into the CU and the DU. Between the core (e.g., 5GC (5G core) or NGC (next generation core)) network and the radio network (RAN), the base station may be implemented in a structure in which the CU, DU, and RU are arranged in that order. The interface between the CU and the distributed unit (DU) may be referred to as an F1 interface.

[0276] A centralized unit (CU) can be connected to one or more DUs and can be responsible for functions at a higher layer than the DU. For example, the CU can be responsible for functions at the radio resource control (RRC) and packet data convergence protocol (PDCP) layers, while the DU and RU can be responsible for functions at lower layers. The DU can perform some functions (high PHY) of the radio link control (RLC), media access control (MAC), and physical (PHY) layers, while the RU can be responsible for the remaining functions (low PHY) of the PHY layer. In addition, for example, a digital unit (DU) can be included in a distributed unit (DU) depending on the implementation of a distributed deployment of the base station. Hereinafter, unless otherwise defined, the operations of DU (digital unit) and RU are described, but various embodiments of the present disclosure can be applied to both a base station arrangement including a CU and an arrangement in which the DU is directly connected to the core network (i.e., a base station in which the CU and DU are integrated into one entity (e.g., an NG-RAN node)).

[0277] According to one embodiment, a node performing LDPC decoding in a receiving device (600) according to embodiments of the present disclosure may be a DU (2810), an RU (2820), and / or another node (e.g., an MMU, a BBU). Depending on which node the channel decoding block is performed in, the functional separation of the distributed arrangement may be defined in various ways, and a detailed description thereof is described through FIG. 29. As a device for decoding an uplink signal according to LDPC encoding, the receiving device (600) may be a DU (2810), an RU (2820), and / or another node (e.g., an MMU, a BBU).

[0278] Figure 29 shows an example of function split of network entities. As wireless communication technology advances (e.g., 5G (5 th With the introduction of 5G communication systems (or NR (new radio) communication systems), the frequency bands used have increased further. As the cell radius of base stations has become significantly smaller, the number of RUs required for installation has also increased. Furthermore, in 5G communication systems, the amount of data transmitted has increased by a factor of up to ten, significantly increasing the transmission capacity of wired networks transmitted to the fronthaul. Due to the factors described above, the installation cost of wired networks in 5G communication systems may increase significantly. Therefore, in order to lower the transmission capacity of wired networks and reduce the installation cost of wired networks, 'function split' can be utilized, which transfers some of the functions of the modem of the DU to the RU to lower the transmission capacity of the fronthaul. Although described as RU below, the function split described below can be equally applied not only to RUs but also to the relationship between the MMU and the DU.

[0279] To reduce the burden on the DU, the role of the RU, which is traditionally solely responsible for RF functions, can be expanded to include some physical layer functions. As the RU performs higher-layer functions, its throughput increases, which can increase transmission bandwidth in the fronthaul while reducing latency requirements due to response processing. However, as the RU performs higher-layer functions, virtualization gains decrease, and the RU's size, weight, and cost increase. Considering the trade-offs between the advantages and disadvantages described above, implementing an optimal functional separation is required.

[0280] Referring to Figure 29, the functional separations in the physical layer below the MAC layer are illustrated. For the downlink (DL) that transmits signals to terminals through a wireless network, the base station can sequentially perform channel encoding / scrambling, modulation, layer mapping, antenna mapping, RE mapping, digital beamforming (e.g., precoding), iFFT transform / CP insertion, and RF transform. For the uplink (UL) that receives signals from terminals through a wireless network, the base station can sequentially perform RF transform, FFT transform / CP removal, digital beamforming (pre-combining), RE demapping, channel estimation, layer demapping, demodulation, and decoding / descrambling. The separation of uplink and downlink functions can be defined in various types depending on the needs of vendors, discussions in standards, etc., according to the above-described trade-offs.

[0281] In the first functional separation (2905), the RU performs the RF function, and the DU performs the PHY function. The first functional separation is one in which the PHY function is not actually implemented in the RU, and may be referred to as Option 8, for example. In the second functional separation (2910), the RU performs iFFT conversion / CP insertion in the DL and FFT conversion / CP removal in the UL of the PHY function, and the DU performs the remaining PHY functions. As an example, the second functional separation (2910) may be referred to as Option 7-1. In the third functional separation (2920a), the RU performs iFFT conversion / CP insertion in the DL and FFT conversion / CP removal and digital beamforming in the UL of the PHY function, and the DU performs the remaining PHY functions. As an example, the third functional separation (2920a) may be referred to as Option 7-2x Category A. In the fourth functional separation (2920b), the RU performs up to digital beamforming in both the DL and UL, and the DU performs upper PHY functions after the digital beamforming. For example, the fourth functional separation (2920b) may be referred to as Option 7-2x Category B. In the fifth functional separation (2925), the RU performs up to RE mapping (or RE demapping) in both the DL and UL, and the DU performs upper PHY functions after RE mapping (or RE demapping). For example, the fifth functional separation (2925) may be referred to as Option 7-2. In the sixth functional separation (2930), the RU performs up to modulation (or demodulation) in both the DL and UL, and the DU performs upper PHY functions after modulation (or demodulation). For example, the sixth functional separation (2930) may be referred to as Option 7-3. In the 7th functional separation (2940), the RU performs encoding / scrambling (or decoding / descrambling) in both the DL and UL, and the DU performs subsequent upper PHY functions up to modulation (or demodulation).For example, the seventh functional separation (2940) may be referred to as Option 6.

[0282] In one embodiment, when a large amount of signal processing is expected, such as in the FR 1 MMU, functional separation at a relatively high layer (e.g., the fourth functional separation (2920b)) may be required to reduce fronthaul capacity. In addition, functional separation at too high a layer (e.g., the sixth functional separation (2930)) may complicate the control interface and cause a burden on the implementation of the RU due to the inclusion of a large number of PHY processing blocks within the RU. Therefore, appropriate functional separation may be required depending on the arrangement and implementation method of the DU and the RU.

[0283] In one embodiment, if the DU cannot process precoding of data received from the RU (i.e., if the RU has limited precoding capability), the third functional separation (2920a) or a lower functional separation (e.g., the second functional separation (2910)) may be applied. Conversely, if the DU has the capability to process precoding of data received from the DU, the fourth functional separation (2920b) or a higher functional separation (e.g., the sixth functional separation (2930)) may be applied.

[0284] The O-RAN standard distinguishes the types of O-RUs depending on whether the precoding function is located at the interface of the O-DU or the O-RU interface. For example, the RU may perform operations according to the functional separation of the third functional separation (2920a) (which may be referred to as category A (CAT-A)) or the fourth functional separation (2920b) (which may be referred to as category B (CAT-B)) for performing beamforming processing. In other words, an O-RU that does not perform precoding (i.e., has low complexity) may be referred to as a CAT-A O-RU. An O-RU that performs precoding may be referred to as a CAT-B O-RU. Additionally, for example, channel estimation may also be performed in the O-RU instead of the O-DU. To improve uplink performance, the O-RU may operate according to the sixth functional separation (2930) (Option 7-3).

[0285] Hereinafter, the upper-PHY refers to the physical layer processing handled in the DU of the fronthaul interface. For example, the upper-PHY may include FEC encoding / decoding, scrambling, and modulation / demodulation. The lower-PHY refers to the physical layer processing handled in the RU of the fronthaul interface. For example, the lower-PHY may include FFT / iFFT, digital beamforming, PRACH (physical random access channel) extraction and filtering. However, the above-described criteria do not exclude embodiments through other functional separations. The functional configuration, signaling, or operation of FIGS. 5 to 14b described below may be applied not only to the third functional separation (2920a), the fourth functional separation (2920b), but also to other functional separations (e.g., the sixth functional separation (2930).

[0286] In Fig. 29, the cues between the DU and the RU are also shown. For example, channel estimation can be performed in the O-RU instead of the O-DU. To improve uplink performance, the O-RU may also operate according to the sixth functional separation (2930) (Option 7-3).

[0287] In embodiments, an electronic device in a communication system or a broadcasting system is provided. The electronic device may include at least one processor and a memory storing instructions. The instructions, when executed by the at least one processor, may cause the electronic device to obtain a signal encoded through a channel code, obtain a first input sequence for the signal, determine a change region among the first input sequence based on a lifting size for the channel code and a number of bits to be encoded in a code block, obtain second candidate input sequences corresponding to combinations in which each value of the change region is different based on the first input sequence, and decode each candidate input sequence from at least a part of the second candidate input sequences, thereby providing a final decoding result.

[0288] For example, the change region may be determined based on the size of the LLR value at a corresponding position of the first input sequence within the search range. The size of the search range may be determined based on the number of bits to be encoded in the code block, the number of shortened filling bits for transmission of the signal, and the number of systematic puncturing bits corresponding to twice the lifting size.

[0289] For example, the search range may correspond to the positions of bits to be encoded in the code block, from the next position of the systematic puncture bits corresponding to twice the lifting size, to the positions of the bits from which the filling bits are excluded.

[0290] For example, the search range may correspond to the positions of bits to be encoded in the code block from the beginning of the code block, excluding the filling bits and the systematic puncturing bits corresponding to twice the lifting size.

[0291] For example, the channel code may include an LDPC (low density parity check) code. The lifting size may be determined according to an index associated with a parity check matrix of the LDPC code. The number of bits to be encoded in the code block may be determined according to the base graph of the LDPC code and the lifting size.

[0292] For example, the first input sequence may represent an estimated intrinsic log-likelihood ratio (LLR) before VN (variable node) update and CN (check node) update according to belief-propagation are performed.

[0293] In embodiments, an electronic device in a communication system or a broadcasting system is provided. The electronic device may include at least one processor and a memory storing instructions. The instructions, when executed by the at least one processor, may cause the electronic device to obtain a signal encoded through a channel code, obtain a first input sequence for the signal, determine a change region among a systematic part and a parity part of the first input sequence based on a result of decoding belief-propagation for the first input sequence, obtain second candidate input sequences corresponding to combinations in which each value of the change region is different based on the first input sequence, and decode each candidate input sequence from at least some of the second candidate input sequences, thereby providing a final decoding result.

[0294] For example, the change region may be determined based on the size of the LLR value at a corresponding position in the sequence according to the result of the decoding within the search range. The search range may include systematic puncturing bits.

[0295] For example, the search range may correspond to the location of bits updated through VN (variable node) update and CN (check node) update according to the trust propagation.

[0296] For example, the search range may correspond to the positions of bits from which shortened filling bits are excluded for transmission of the signal in a systematic portion corresponding to the number of bits to be encoded in the code block.

[0297] For example, the search range may correspond to the positions of systematic puncturing bits corresponding to twice the lifting size within the systematic portion corresponding to the number of bits to be encoded in the code block.

[0298] For example, the channel code may include an LDPC (low density parity check) code. The systematic portion and the parity portion may be determined according to a lifting size for the LDPC code and a base graph of the LDPC code.

[0299] For example, the first input sequence may represent an estimated intrinsic log-likelihood ratio (LLR) before the VN (variable node) update and the CN (check node) update according to the belief propagation are performed. The result of decoding the first input sequence may represent a posteriori LLR after the VN update and the CN update according to the belief propagation are performed.

[0300] In embodiments, an electronic device in a communication system or a broadcasting system is provided. The electronic device may include at least one processor and a memory storing instructions. The instructions, when executed by the at least one processor, may cause the electronic device to obtain a signal encoded through a channel code, obtain a first input sequence for the signal, determine a change region among puncturing bits of a systematic part and puncturing bits of a parity part of the first input sequence, obtain second candidate input sequences corresponding to combinations in which each value of the change region is different based on the first input sequence, and decode each candidate input sequence from at least a part of the second candidate input sequences, thereby providing a final decoding result.

[0301] For example, the change region may be determined based on the size of the LLR value at a corresponding position of the first input sequence within the search range. The search range may correspond to the positions of at least some of the punctured bits of the parity portion, and may not correspond to the positions of the punctured bits of the systematic portion.

[0302] For example, the search range may correspond to the positions of at least some of the puncture bits of the systematic portion, and may not correspond to the positions of the puncture bits of the parity portion.

[0303] For example, the number of the second candidate input sequences may be determined as a power of 2 according to the number of bit indices corresponding to the change area.

[0304] For example, the search range may be different from the area of ​​bits transmitted over the wireless channel among the entire encoding area for the channel code.

[0305] For example, the channel code may include an LDPC (low density parity check) code. The systematic portion and the parity portion may be determined according to a lifting size for the LDPC code and a base graph of the LDPC code.

[0306] For example, the first input sequence may represent an estimated intrinsic log-likelihood ratio (LLR) before VN (variable node) update and CN (check node) update according to belief-propagation are performed.

[0307] In embodiments, a decoding method for a channel code in a communication system is provided. The method includes the steps of receiving a signal encoded and transmitted with a used channel code, generating a first decoder input sequence (or vector, array, etc.) from the signal, generating at least one modified second decoder input sequence by modifying at least one element in the first decoder input sequence, performing decoding on each of the at least one modified second decoder input sequence, and determining a final decoding result based on results of the decoding performed on each of the at least one modified second decoder input sequence, wherein at least one element to be modified in the first decoder input sequence can be selected from a limited region determined in consideration of a structure of the channel code.

[0308] In embodiments, a method for decoding a channel code in a communication system is provided. The method may include the steps of: receiving a signal encoded and transmitted with a used channel code; generating a first decoder input sequence (or vector, array, etc.) from the signal; performing decoding on the first decoder input sequence; identifying a second decoder output sequence generated or updated by the decoding; identifying or determining one or more element positions based on the second decoder output sequence; modifying at least one element of the first decoder input sequence based on the element positions identified or determined based on the second decoder output sequence to generate at least one modified third decoder input sequence(s); performing decoding on each of the at least one modified third decoder input sequence(s); and determining a final decoding result based on results of decoding performed on each of the at least one modified third decoder input sequence(s).

[0309] In embodiments, a decoding method for a channel code in a communication system is provided. The method may include the steps of receiving a signal encoded and transmitted with a used channel code, generating a first decoder input sequence (or a vector, an array, etc.) from the signal, generating at least one modified second decoder input sequence by adding one or more elements to the first decoder input sequence, performing decoding on each of the at least one modified second decoder input sequence, and determining a final decoding result based on results of the decoding performed on each of the at least one modified second decoder input sequence. At least one element to be modified in the first decoder input sequence may be selected from a limited region determined in consideration of the structure of the channel code.

[0310] The present disclosure aims to improve the decoding performance of channel codes, such as turbo codes and low-density parity-check codes (LDPC codes), which gradually update a posterior probability, a posteriori log-likelihood ratio (AP-LLR), etc. of codeword bits through iterative processing in a communication or broadcasting system. Theoretically, channel codes have low error-correction performance when the code dimension (the number of information bits to be encoded, the encoder input length) and the code length (the number of codeword bits obtained by encoding, the encoder output length) are short. Specifically, even at the same code rate (the ratio of the code dimension to the code length), the error-correction performance when the code dimension and length are short is lower than that when the code dimension and length are long. In addition, turbo codes and LDPC codes are characterized by a greater degradation in performance when the code dimension and length are short. Accordingly, the present disclosure considers the problem of effectively improving the low error-correction performance that occurs when the dimension and length of channel codes, such as turbo codes and LDPC codes, are short. Specifically, the various embodiments of the present disclosure primarily aim to achieve superior error-correction performance with simpler operations than conventional methods for turbo codes and LDPC codes with short code dimensions and lengths.

[0311] One embodiment of a method for decoding a channel code performed by a receiver in a communication and broadcasting system of the present disclosure comprises the steps of: receiving a signal encoded and transmitted with a channel code used; generating an original decoder input sequence (or vector, array, etc.) such as a log-likelihood ratio (LLR) sequence from the signal; generating at least one modified decoder input sequence by modifying at least one element in the original decoder input sequence; performing decoding based on each of the at least one modified decoder input sequence; and determining a final decoding result based on results obtained from decoding performed on each of the at least one modified decoder input sequence; wherein at least one element to be modified in the original decoder input sequence is determined within a limited range determined based on a structure and characteristics of the channel code used.

[0312] One embodiment of a method for decoding a channel code performed by a receiver in a communication and broadcasting system of the present disclosure is characterized by including the steps of: receiving a signal encoded and transmitted with a channel code used; generating an original decoder input sequence (or vector, array, etc.) such as a log-likelihood ratio (LLR) sequence from the signal; performing decoding based on the original decoder input sequence; obtaining a decoder output sequence generated by a decoder when decoding based on the original decoder input sequence fails; determining a position at which a value of at least one element is to be changed based on the decoder output sequence; generating at least one or more modified decoder input sequences by changing at least one element of the original decoder input sequence based on the position of the element at which the value is to be changed; performing decoding based on each of the at least one or more modified decoder input sequences; and determining a final decoding result based on results obtained from decoding performed on each of the at least one or more modified decoder input sequences.

[0313] A decoding device and method according to various embodiments of the present disclosure generate at least two modified decoder input sequences based on an original decoder input sequence, perform decoding based on each of them, and then combine the results to significantly improve decoding performance. In particular, the decoding device and method according to various embodiments of the present disclosure lower the complexity by searching a smaller range than conventional decoding methods and devices when determining elements to be modified in the original decoder input sequence. Therefore, the various embodiments of the present disclosure achieve an error-correction performance at a nearly similar level while minimizing additional complexity and delay compared to conventional methods when generating a modified decoder input sequence.

[0314] A decoding device and method according to various embodiments of the present disclosure generate at least two modified decoder input sequences based on an original decoder input sequence, perform decoding based on each of them, and then combine the results to significantly improve decoding performance. In particular, a decoding device and method according to various embodiments of the present disclosure determines an element to be modified in the original decoder input sequence based on a decoder output sequence obtained after one decoding. Various embodiments of the present disclosure achieve a better error-correction performance while reducing complexity and delay compared to conventional methods by using a method of modifying a decoding input sequence based on the decoding output sequence.

[0315] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0316] For one or more embodiments, at least one of the components described in one or more of the preceding drawings may be configured to perform one or more operations, techniques, processes, and / or methods as described herein. For example, a processor (e.g., a baseband processor) described herein with respect to one or more of the preceding drawings may be configured to operate according to one or more examples described herein. For another example, circuitry associated with a user equipment (UE), a base station, a network element, and the like, as described above with respect to one or more of the preceding drawings, may be configured to operate according to one or more examples described herein.

[0317] Any of the embodiments described above may be combined with any other embodiment (or combination of embodiments) unless explicitly stated otherwise. The foregoing description of one or more implementations provides examples and descriptions, but is not intended to be exhaustive or limit the scope of the embodiments to the precise forms disclosed. Modifications and variations are possible in light of the above teachings or may be learned from practicing various embodiments.

[0318] 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.

[0319] When implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured to be executed by one or more processors in an electronic device. The one or more programs include instructions that cause the electronic device to execute methods according to embodiments described in the claims or specification of the present disclosure. The one or more programs may be provided as a computer program product. The computer program product may be traded between a seller and a buyer as a commodity. The computer program product may be distributed in the form of a machine-readable storage medium (e.g., compact disc read only memory (CD-ROM)), or may be distributed online (e.g., downloaded or uploaded) via an application store (e.g., Play Store™) or directly between two user devices (e.g., smart phones). In the case of online distribution, at least a portion of the computer program product may be temporarily stored or temporarily created in a device-readable storage medium, such as the memory of a manufacturer's server, an application store's server, or an intermediary server.

[0320] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage devices, compact disc-ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage devices, magnetic cassettes, or may be stored in memories formed by a combination of some or all of these. In addition, each configuration memory may include multiple copies.

[0321] Additionally, the program may be stored on an attachable storage device that is accessible via a communication network, such as the Internet, an intranet, a local area network (LAN), a wide area network (WAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device implementing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device implementing an embodiment of the present disclosure.

[0322] In the specific embodiments of the present disclosure described above, components included in the disclosure are expressed singularly or plurally, depending on the specific embodiment presented. However, the singular or plural expressions are selected to suit the presented situation for convenience of explanation, and the present disclosure is not limited to singular or plural components. Components expressed in plural may be composed of singular elements, or components expressed in singular may be composed of plural elements.

[0323] According to embodiments, one or more of the components or operations of the aforementioned components may be omitted, or one or more other components or operations may be added. Alternatively or additionally, a plurality of components (e.g., modules or programs) may be integrated into a single component. In such a case, the integrated component may perform one or more functions of each of the plurality of components identically or similarly to those performed by the corresponding component among the plurality of components prior to the integration. According to embodiments, the operations performed by a module, program, or other component may be executed sequentially, in parallel, iteratively, or heuristically, or one or more of the operations may be executed in a different order, omitted, or one or more other operations may be added.

[0324] Meanwhile, although the detailed description of the present disclosure has described specific embodiments, it is obvious that various modifications are possible within the scope of the present disclosure.

Claims

1. In electronic devices in communication systems or broadcasting systems; at least one processor; and Contains memory that stores instructions, The above instructions, when executed by the at least one processor, cause the electronic device to: Obtaining a signal encoded through a channel code, Obtain a first input sequence for the above signal, Based on the lifting size for the channel code and the number of bits to be encoded in the code block, a change region is determined among the first input sequence, Obtain second candidate input sequences corresponding to combinations in which each value of the change area is different based on the first input sequence, causing each candidate input sequence to be decoded from at least some of the second candidate input sequences, thereby providing a final decoded result; Electronic devices.

2. In claim 1, The above change region is determined based on the size of the LLR value at the corresponding position of the first input sequence within the search range, The size of the above search range is determined based on the number of bits to be encoded in the code block, the number of shortened filling bits for transmission of the signal, and the number of systematic puncturing bits corresponding to twice the lifting size. Electronic devices.

3. In claim 2, The above search range corresponds to the positions of the bits to be encoded in the code block, from the next position of the systematic puncture bits corresponding to twice the lifting size, to the positions of the bits from which the filling bits are excluded. Electronic devices.

4. In claim 2, The above search range corresponds to the positions of bits from the beginning of the code block to be encoded in the code block, excluding the filling bits and the systematic puncturing bits corresponding to twice the lifting size. Electronic devices.

5. In claim 1, The above channel code includes a LDPC (low density parity check) code, The above lifting size is determined according to the index associated with the parity check matrix of the LDPC code, The number of bits to be encoded in the above code block is determined according to the base graph of the LDPC code and the lifting size. Electronic devices.

6. In claim 1, The first input sequence above represents an estimated intrinsic LLR (log-likelihood ratio) before VN (variable node) update and CN (check node) update according to belief-propagation are performed. Electronic devices.

7. In electronic devices in communication systems or broadcasting systems; at least one processor; and Contains memory that stores instructions, The above instructions, when executed by the at least one processor, cause the electronic device to: Obtaining a signal encoded through a channel code, Obtain a first input sequence for the above signal, Based on the result of decoding the belief-propagation for the first input sequence, a change region is determined among the systematic part and the parity part of the first input sequence, Obtain second candidate input sequences corresponding to combinations in which each value of the change area is different based on the first input sequence, causing each candidate input sequence to be decoded from at least some of the second candidate input sequences, thereby providing a final decoded result; Electronic devices.

8. In claim 7, The above change area is determined according to the size of the LLR value at the corresponding position of the sequence according to the result of the decoding within the search range, The above search range includes systematic perforation bits, Electronic devices.

9. In claim 8, The above search range corresponds to the location of the bits updated through the VN (variable node) update and the CN (check node) update according to the above trust propagation. Electronic devices.

10. In claim 8, The above search range corresponds to the positions of bits from which the shortened filling bits for transmission of the signal are excluded in the systematic part corresponding to the number of bits to be encoded in the above code block. Electronic devices.

11. In claim 8, The above search range corresponds to the positions of systematic puncture bits corresponding to twice the lifting size within the systematic part corresponding to the number of bits to be encoded in the code block. Electronic devices.

12. In claim 7, The above channel code includes a LDPC (low density parity check) code, The above systematic part and the above parity part are determined according to the lifting size for the LDPC code and the base graph of the LDPC code. Electronic devices.

13. In claim 7, The above first input sequence represents the estimated intrinsic LLR (log-likelihood ratio) before the VN (variable node) update and CN (check node) update according to the trust propagation are performed, The result of decoding for the first input sequence is a posteriori LLR after the VN update and the CN update according to the trust propagation are performed. Electronic devices.

14. In electronic devices in communication systems or broadcasting systems; at least one processor; and Contains memory that stores instructions, The above instructions, when executed by the at least one processor, cause the electronic device to: Obtaining a signal encoded through a channel code, Obtain a first input sequence for the above signal, Determine a change area among the punctured bits of the systematic part and the punctured bits of the parity part of the first input sequence, Obtain second candidate input sequences corresponding to combinations in which each value of the change area is different based on the first input sequence, causing each candidate input sequence to be decoded from at least some of the second candidate input sequences, thereby providing a final decoded result; Electronic devices.

15. In claim 14, The above change region is determined based on the size of the LLR value at the corresponding position of the first input sequence within the search range, The above search range corresponds to the positions of at least some of the punctured bits of the parity portion, and does not correspond to the positions of the punctured bits of the systematic portion. Electronic devices.

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