Encoding diversity method and apparatus for code rate matching polar code in wireless communication system

Abstract

The present disclosure relates to a 5G or 6G communication system for supporting a data transmission rate higher than that of a 4G communication system such as LTE. A method for transmitting a polar code in a wireless communication system, according to an embodiment of the present disclosure, comprises the steps of: performing code rate matching interleaving and code rate matching on codeword bits corresponding to the polar code; grouping, into a first bit group and a second bit group including different numbers of bits, the codeword bits on which the code rate matching interleaving and code rate matching have been performed; performing channel interleaving on the first bit group and / or the second bit group; and allocating, to two or more fading channels, the two bit groups on which the channel interleaving has been performed, and transmitting same.

Description

Code diversity method and device for rate-matched polar codes in wireless communication systems

[0001] The present disclosure relates to a communication method and device using a polar code in a wireless communication system.

[0002] Looking back at the evolution of wireless communication over successive generations, technologies have primarily been developed for human-facing services such as voice, multimedia, and data. With the commercialization of 5G (5th-generation) communication systems, an explosive increase in connected devices is expected to be connected to communication networks. Examples of networked objects include vehicles, robots, drones, home appliances, displays, smart sensors installed in various infrastructures, construction equipment, and factory equipment. Mobile devices are expected to evolve into diverse form factors, including augmented reality glasses, virtual reality headsets, and holographic devices. In the 6th-generation (6G) era, efforts are being made to develop improved 6G communication systems to connect hundreds of billions of devices and objects and provide diverse services. For this reason, 6G communication systems are often referred to as "beyond 5G."

[0003] The 6G communication system, expected to be realized around 2030, will have a maximum transmission speed of terabytes per second (i.e., 1,000 gigabits per second) and a wireless latency of 100 microseconds (μsec). In other words, compared to 5G, the transmission speed in a 6G communication system will be 50 times faster, while the wireless latency will be reduced to one-tenth.

[0004] To achieve these high data rates and ultra-low latency, 6G communication systems are being considered for implementation in the terahertz band (e.g., from 95 gigahertz (GHz) to 3 terahertz (THz)). Compared to the millimeter wave (mmWave) band introduced in 5G, the terahertz band is expected to experience more severe path loss and atmospheric absorption, making it more crucial to ensure signal reach, or coverage, in this band. Key technologies to ensure coverage include radio frequency (RF) components, antennas, new waveforms that offer better coverage than OFDM (orthogonal frequency division multiplexing), beamforming, and multiple antenna transmission technologies such as massive multiple-input and multiple-output (MIMO), full-dimensional MIMO (FD-MIMO), array antennas, and large-scale antennas. In addition, new technologies such as metamaterial-based lenses and antennas, high-dimensional spatial multiplexing using orbital angular momentum (OAM), and reconfigurable intelligent surfaces (RIS) are being discussed to improve the coverage of terahertz band signals.

[0005] In addition, in order to improve frequency efficiency and system network, 6G communication systems are developing full duplex technology that utilizes the same frequency resources for uplink and downlink at the same time; network technology that integrates satellites and high-altitude platform stations (HAPS); network structure innovation technology that supports mobile base stations and enables optimization and automation of network operation; dynamic spectrum sharing technology through collision avoidance based on spectrum usage prediction; AI-based communication technology that utilizes artificial intelligence (AI) from the design stage and internalizes end-to-end AI support functions to realize system optimization; and next-generation distributed computing technology that realizes services with complexity that exceeds the limits of terminal computing capabilities by utilizing ultra-high-performance communication and computing resources (mobile edge computing (MEC), cloud, etc.). In addition, efforts are being made to further strengthen connectivity between devices, further optimize networks, promote softwareization of network entities, and increase the openness of wireless communications through the design of new protocols to be used in 6G communication systems, the implementation of hardware-based security environments, the development of mechanisms for the safe use of data, and the development of technologies for maintaining privacy.

[0006] Research and development of these 6G communication systems are expected to enable a new level of hyper-connected experience through the hyper-connectivity of 6G communication systems, which encompass not only connections between things but also connections between people and things. Specifically, 6G communication systems are expected to enable services such as truly immersive extended reality (Truly Immersive XR), high-fidelity mobile holograms, and digital replicas. Furthermore, services such as remote surgery, industrial automation, and emergency response, which are provided through enhanced security and reliability, will find application in diverse fields such as industry, healthcare, automotive, and home appliances.

[0007] Channel coding is a technology that utilizes redundant bits during data transmission to transmit messages with high reliability. For this purpose, the use of error-correcting codes is essential. Claude Shannon defined the maximum amount of information that can be transmitted for reliable communication as "channel capacity." Since then, numerous error-correcting codes have been studied to approach Shannon's channel capacity. Starting with classical codes such as Hamming, Bose-Chaudhuri-Hocquenghem (BCH), and Reed-Solomon (RS) codes, various modern codes such as turbo codes, low-density parity-check (LDPC), and polar codes have been newly proposed. LDPC codes and polar codes are known as representative capacity-approaching and capacity-achieving codes, respectively, and have been adopted as channel codes in the 5G NR (new radio) standard.

[0008] Among them, polar codes are error-correcting codes first proposed by Arikan in 2009. They are the first codes for which it has been theoretically proven that they asymptotically achieve channel capacity with low decoding complexity as the code length increases in various types of binary-input discrete memoryless channels (BI-DMC). When successive cancellation (SC) decoding is performed, there is no advantage in decoding performance compared to existing LDPC codes or turbo codes. However, decoding performance is greatly improved when successive cancellation list (SC-List: SCL) decoding and SCL decoding utilizing cyclic redundancy check (CRC) code / parity-check (PC) code are used. In particular, 3GPP (3 rd Through the 5G standardization process of the Generation Partnership Project, CRC and PC codes were simultaneously utilized to secure excellent decoding performance and error detection performance, and based on this, it was adopted as an error correction code for the control channel of ultra-wideband communication (enhanced mobile broadband: eMBB). Furthermore, polar codes are considered as a candidate for channel codes for B5G (beyond 5G) and 6G communication based on their strong decoding performance at short lengths.

[0009] Following 5G communications, B5G and 6G communications require in-depth research on code design and decoding technologies that can ensure superior performance for more practical channel models. 6G communications have high requirements for ultra-high bandwidth, ultra-high reliability, and ultra-low latency, as well as low-latency conditions and channel diversity. To ensure diversity, encoded signals can be transmitted through non-homogeneous (or non-ergodic) channels and resources. For example, 5G communications are considering scenarios such as frequency hopping, which allocates modulation codewords to two or more different resource blocks, or resource allocation types. If the given non-homogeneous channels can be effectively utilized to achieve greater diversity, this will complement the weaknesses of 5G-NR's bit-interleaved coded-modulation (BICM) design and lead to even better performance.

[0010] Various studies have been conducted on coded diversity transmission over block fading channels. Representative studies have focused on the number of fading blocks. When, the code rate In full-diversity (diversity- ) or guarantee the code rate Transmission methods with diversity-2 in. In particular, in the case of LDPC (low-density parity-check) codes, the code rate Diversity in - A root-LDPC code that obtains a high code rate is proposed. In , a generalized root protograph LDPC code with diversity-2 has been proposed. A diversity acquisition method for turbo codes has also been proposed in similar situations. However, since these codes are fundamentally designed to secure diversity performance in block fading channels, they have the disadvantage of not being able to guarantee performance in AWGN (additive white Gaussian noise) channels. For polar codes, research on diversity transmission methods is necessary, and in particular, research on the design of a BICM system suitable for various transmission environments is needed.

[0011] The present disclosure proposes a method and device for transmitting code diversity of rate-matched polar codes in a wireless communication system.

[0012] According to an embodiment of the present disclosure, a method for transmitting a polar code in a wireless communication system includes the steps of performing rate matching interleaving and rate matching on codeword bits corresponding to the polar code; grouping the codeword bits on which the rate matching interleaving and rate matching were performed into a first bit group and a second bit group including different numbers of bits; performing channel interleaving on at least one of the first bit group and the second bit group; and allocating and transmitting two bit groups on which the channel interleaving was performed to two or more fading channels.

[0013] According to an embodiment of the present disclosure, an electronic device for transmitting a polar code in a wireless communication system comprises: a transceiver; and at least one processor; wherein the at least one processor is configured to perform rate matching interleaving and rate matching on codeword bits corresponding to the polar code, group the codeword bits subjected to the rate matching interleaving and rate matching into a first bit group and a second bit group including different numbers of bits, perform channel interleaving on at least one of the first bit group and the second bit group, and assign and transmit two bit groups subjected to the channel interleaving to two or more fading channels.

[0014] The present disclosure provides a method and device for transmitting rate-matched polar codes with coding diversity in a wireless communication system, thereby presenting an enhanced polar code BICM design and transmission technology having a large decoding performance gain according to diversity gain in a block fading channel, thereby being flexibly applicable to various rate-matched polar codes and maintaining AWGN performance.

[0015] Figure 1 is a diagram illustrating the channel synthesis and channel separation process for polar codes.

[0016] Figure 2 is a diagram schematically showing the binary domination relationship for the indices of polar code separation channels (N=8).

[0017] Figure 3 is a diagram showing a sequence of bit indices of polar symbols sorted in ascending order of reliability in matrix form.

[0018] Figure 4 is a diagram illustrating the encoding process of a polar code.

[0019] Figure 5 is a diagram showing an example of a method for allocating a separate channel according to the length of an uplink control information (UCI) message.

[0020] Figure 6 is a diagram illustrating a subblock interleaver.

[0021] Figure 7 is a diagram illustrating a circular buffer for matching the code rate of polar codes.

[0022] Figure 8 is a diagram illustrating a triangular interleaver used as a channel interleaver.

[0023] Figure 9 is a drawing showing a block diagram of a block fading transmission and reception for transmission of encoded data.

[0024] FIG. 10 is a drawing showing an example of a block diagram of a polar coded BICM system in a wireless communication system.

[0025] Fig. 11 is a drawing showing an example of a block diagram of a polar coded BICM system in a wireless communication system.

[0026] Figure 12a is a diagram illustrating a modified SNR (signal noise rate)-BLER (block error rate) graph according to the diversity order.

[0027] Figure 12b is a diagram showing the results of simulating the decoding diversity order that can be achieved depending on the code rate.

[0028] Figure 13 is a drawing showing an example of a transmission block diagram of a perforated polar code.

[0029] Figure 14 is a drawing showing an example of a transmission block diagram of a shortened polar code.

[0030] Figure 15 shows the code word bits of the polar code. A diagram illustrating an example where a block is allocated as a fading channel and the fading channel is fading (i.e., dynamically perforated).

[0031] FIG. 16a and FIG. 16b are diagrams illustrating an example of rate-matched polar code transmission that is perforated (or shortened) through a block fading channel.

[0032] FIG. 17 is a block diagram illustrating an example of a bit-interleaved coded-modulation (BICM) system according to one embodiment of the present disclosure.

[0033] FIG. 18 is a diagram illustrating an example of shortened polar code transmission over a block fading channel according to one embodiment of the present disclosure.

[0034] FIG. 19 is a drawing illustrating an example of a BICM system transmission block diagram for a shortened polar code when using a code sequence with a rate-matching interleaver according to an embodiment of the present disclosure.

[0035] FIG. 20 is a diagram illustrating fading channel allocation of polar codes when a code sequence is used as a rate-matching interleaver according to one embodiment of the present disclosure.

[0036] FIG. 21 is a drawing illustrating an example of a BICM system transmission block diagram for a shortened polar code when a sub-block interleaver is used as a rate-matching interleaver according to one embodiment of the present disclosure.

[0037] FIG. 22 is a diagram illustrating polar code fading channel allocation when a subblock interleaver is used as a rate-matching interleaver according to one embodiment of the present disclosure.

[0038] FIG. 23 is a drawing illustrating an example of a BICM system transmission block diagram for a shortened polar code when a sub-block interleaver satisfying arbitrary binary domination is used as a rate-matching interleaver according to one embodiment of the present disclosure.

[0039] FIG. 24 is a drawing illustrating an example of a BICM system transmission block diagram for a perforated polar code according to one embodiment of the present disclosure.

[0040] FIG. 25a, FIG. 25b, and FIG. 25c illustrate the use of a code sequence interleaver as a rate-matching interleaver in a block fading channel according to an embodiment of the present disclosure, and parameters for grouping. go BLER of the shortened polar sign in case of = 10 -3 This is a diagram showing the results of the required SNR[db] achieved.

[0041] FIG. 26a and FIG. 26b illustrate a case in which a sub-block interleaver is used as a rate-matching interleaver in a block fading channel according to an embodiment of the present disclosure, and adaptive addition-fixing is applied, and the BLER of the shortened polar code is 10. -3 This is a diagram showing the results of the required SNR [dB] achieved.

[0042] FIG. 27 is a diagram showing the results of comparing the BLER performance of shortened polar codes according to a decoding method in a block fading channel according to one embodiment of the present disclosure.

[0043] FIG. 28a and FIG. 28b are diagrams showing the results of comparing the high-order modulation performance of a shortened polar code in an AWGN channel according to one embodiment of the present disclosure.

[0044] FIG. 29 is a flowchart illustrating the operation of an electronic device according to one embodiment of the present disclosure.

[0045] FIG. 30 is a structural diagram illustrating the structure of an encoding device according to an embodiment of the present disclosure.

[0046] The operating principles of the present disclosure are described in detail below with reference to the attached drawings. In the following description of the present disclosure, detailed descriptions of related known functions or configurations will be omitted if they are deemed to unnecessarily obscure the gist of the present disclosure. Furthermore, the terms described below are defined based on the functions of the present disclosure and may vary depending on the intent or custom of the user or operator. Therefore, their definitions should be based on the overall content of this specification.

[0047] For the same reason, some components in the attached drawings are omitted or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect the actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0048] The advantages and features of the present disclosure, and methods for achieving them, will become clearer with reference to the embodiments described below in detail with the accompanying drawings. However, the present disclosure is not limited to the embodiments disclosed below and may be implemented in various different forms. The various embodiments are provided to ensure that the present disclosure is complete and to fully convey the scope of the present disclosure to those skilled in the art, and the present disclosure is defined solely by the scope of the claims. Like reference numerals designate like elements throughout the specification.

[0049] At this time, it will be understood that each block of the processing flow diagrams and combinations of the flow diagrams 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 processor of the computer or other programmable data processing equipment create a means for performing the functions described in the flow diagram block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can direct 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 flow diagram 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).

[0050] 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.

[0051] The term "~unit" used in various embodiments of the present disclosure refers to a software or hardware component, and the "~unit" performs certain roles. However, the "~unit" is not limited to software or hardware. The "~unit" may be configured to reside 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, attributes, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functionality 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. Additionally, in various embodiments of the present disclosure, '~bu' may include one or more processors.

[0052] In this disclosure, phrases such as "A and / or B", "A or B", "at least one of A and B", "at least one of A or B", "A, B, or C", "at least one of A, B, and C", and "at least one of A, B, or C" can each include any one of the items listed together in that phrase, or all possible combinations thereof. Terms such as "first", "second", or "first" or "second" may be used merely to distinguish the corresponding component from other corresponding components and do not limit the corresponding components in any other respect (e.g., importance or order).

[0053] In embodiments of the present disclosure, a user equipment (UE) may be a terminal, a mobile station (MS), a cellular phone, a smartphone, a computer, or any other electronic device capable of performing a communication function. In addition, a base station (BS) is a network entity that performs resource allocation to a UE, and may be at least one of a Node B, an eNB (eNode B), a gNB (gNode B), a wireless access unit, a base station controller, or a node on a network.

[0054] Furthermore, the various embodiments of the present disclosure described below may be applied to other communication systems having similar technical backgrounds or channel configurations. Furthermore, the various embodiments of the present disclosure may be applied to other communication systems with some modifications, as determined by a person skilled in the art, without significantly departing from the scope of the present disclosure.

[0055] In specifically describing various embodiments of the present disclosure, the communication system may utilize a wireless communication system, and for example, may utilize a 5G communication system based on the 5G communication standard (NR (New RAN)) proposed by 3GPP (3rd generation partnership project long term evolution), a wireless communication standard standardization organization. In addition, it may be applied to other communication systems with similar technical backgrounds with slight modifications within a range that does not significantly deviate from the scope of the present disclosure, and this may be possible at the discretion of a person skilled in the technical field of the present disclosure. For the convenience of the following description, some terms and names defined in the 3GPP standard may be used. However, the present disclosure is not limited by the above terms and names, and may be equally applied to systems conforming to other standards.

[0056] 본 개시에서 사용되는 약어에 대한 설명은 아래와 같다.

[0057] - AWGNC: additive white Gaussian noise channel

[0058] - AEF: Additional extra freezing

[0059] - B-DMC: binary-input discrete memoryless channel

[0060] - BEC: binary erasure channel

[0061] - BFC: block fading channel

[0062] - BLER: block error rate

[0063] - BPSK: binary phase shift keying

[0064] - CRC: cyclic redundancy check

[0065] - CW: codeword

[0066] - DE: density evolution

[0067] - EF: extra-freezing

[0068] - EEF: extended extra-freezing

[0069] - FFC: fast fading channel

[0070] - IIoT: Industrial internet of things

[0071] - PUCCH: physical uplink control channel

[0072] - PUSCH: physical uplink shared channel

[0073] - QAM: quadrature amplitude modulation

[0074] - QPSK: quadrature phase shift keying

[0075] - SC: successive cancellation

[0076] - SCL: successive cancellation list

[0077] - SNR: signal-to-noise ratio

[0078] - URLLC: ultra-reliable low-latency communications

[0079] For conventional polar codes and 5G-NR codes that perform well in AWGNC or flat fading channels, the structural characteristics of polar codes can significantly degrade decoding performance when specific bit patterns simultaneously fade in non-ergodic block fading channels or multi-block fading channels. In BICM systems, a bit interleaver ensures that codeword bits are evenly distributed across fading blocks, which can secure a certain degree of diversity, but it does not approach the theoretical limit. In addition, there is a drawback in that high diversity cannot be guaranteed over a wide range of code rates for rate-matching polar codes.

[0080] To overcome this, a diversity-oriented polar code transmission method was proposed, which designs an allocation pattern to fading blocks to ensure that the information bits of the pre-designed AWGN code have high diversity. Specifically, We propose a code sequence-based interleaving as an optimal allocation pattern for in-block fading channels. Code rate-( when transmitting in block fading channel ) in diversity- An interleaver having , was found through a kind of greedy search. This technique proposed the first diversity sorting method for polar codes, but the code rate-( ) is specialized for very low code rates, and the overhead problem of having to store the optimal allocation pattern for each code parameter remained as a challenge to be overcome.

[0081] In this disclosure, we propose an enhanced polar coding BICM design and transmission technique that achieves significant performance gains in block fading channels while having wider 'diversity exceeding 2' and 'diversity 2' regions through a novel BICM transmission method that groups codeword bits and then performs individual interleaving. In particular, the method and apparatus proposed in this disclosure have the advantage of being flexibly applicable to various rate-matched polar codes, and can maintain AWGN performance while complying with (or complying with as much as possible with) existing codes.

[0082] Introduction to the ultra-wealthy

[0083] To help understand the embodiments of the present disclosure, polar symbols will first be explained.

[0084] Polar codes are codes that theoretically achieve channel capacity. They obtain polarized channels through channel combining and channel splitting, and select high-quality channels suitable for communication to transmit data. Referring to Figure 1, A vector (or source vector) is composed of information bits and frozen bits and has a dimension of is. The information bit has a binary value of one of {0, 1}, and the fixed bit is usually fixed to 0. After that, the generator matrix , is a codeword vector through multiplication with the Kronecker exponent (power) Creates ( ). At this time is the generating matrix my It means the number of 1s in the th row. And the codeword vector is modulated and iid (independent and identically distributed) channel in symbol units. ( Dog's independent channels The received signal vector passes through the (noted as ) This is it.

[0085] Considering BPSK modulation, the received signal of The th bit value Is It can be expressed as follows. At this time Vector and received signal vector One large combined channel connecting can be defined From The process of obtaining this is called channel synthesis.

[0086] Channel separation is A virtual split channel experienced by each source bit from ( : refers to the process of defining the separation channel indexes. The separation channel is When I entered Transition probability that outputs is defined by. In this case, it is possible to evaluate the reliability and capacity of the separated channels based on Genie-aided SC decoding. That is, as can be seen from the transition probability formula, all previously estimated source bits Assuming that the results are correct, the reliability and capacity of the separated channels can be evaluated sequentially (genie-aided SC decoding).

[0087] At this time Reliability of Based on this, the index can be sorted in order from the lowest quality separation channel to the highest quality separation channel, which is called a polar code sequence. That is, reliability The bits located at the front of the small sign sequence are sent with fixed values, The bits located at the rear of the code sequence are used for data transmission. Methods such as Bhattacharyya parameter estimation, density evolution, and Gaussian approximation can be used to design the code sequence.

[0088] However, these are separated channels by channel parameters (e.g. SNR (signal-to-noise power ratio)). ) may have different dominance relationships. For example, the index Reliability of the human separation channel For , SNR=0dB But at SNR=3dB can be. That is, the optimal information set composition may vary depending on the channel condition. At this time, the dominance relationship between some separate channels, i.e., the 'partial order', may be maintained regardless of the quality of the transmission channel. This means that the dominance relationship between some separate channels changes depending on the channel parameters, but the fixed dominance relationship between some separate channels is always maintained regardless of the channel parameters. This relationship can reduce the complexity of code design. Two of the well-known partial order rules for polar codes are as follows. First, the index , Consider two separate channels (where the binary expansion of each index is in parentheses) (where the MSB position index is , the LSB position index is 0).

[0089] PO (partial order) 1. The result of switching the 1 located in the upper position (i.e. closer to the MSB) and the 0 located in the lower position (i.e. closer to the LSB) is If, is always It has a lower capacity compared to It is expressed as .

[0090] for example, at If , since am.

[0091] PO (partial order) 2. Two-bit index , About And On the other hand, , and this relationship is called binary domination.

[0092] for example, at Back side since And 13 has a binary domination advantage over 5.

[0093] Figure 2 is a diagram schematically showing the binary domination relationship for the indices of polar code separation channels (N=8).

[0094] As described in Figure 1, the dimension is person A virtual split channel in a vector (or source vector) ( : Separation channel index) Separation channel index reliability can be sorted in ascending order according to the sign sequence can be expressed as

[0095] Figure 2 is a diagram schematically illustrating the binary dominance relationship of the separation channels of a polar code with N=8.

[0096] Referring to Figure 2, a separation channel with index 0 ( ) is a binary extension of , it has the lowest reliability among all the separate channels. Next is , i.e., separate channels with indices 1, 2, and 4 ( ) are the separation channels with index 0 ( ) is superior to binary domination. Following Is In binary domination, there is an upper hand. Also, Is to, Is In binary domination, It can be seen that it has binary domination advantage over all other separation channels.

[0097] Furthermore, the 5G-NR standard fundamentally reflects a fixed priority relationship between these separate channels to avoid channel-dependent code design. Furthermore, it flexibly adapts to various code lengths and rates. A single universal nested code (index) sequence for , and the sequence adopted in the 5G-NR standard is as shown in Figure 3.

[0098] Figure 3 is a diagram showing a sequence in which the bit indices of polar symbols are sorted in ascending order of reliability.

[0099] Figure 3 is a single code sequence defined in the 5G NR standard. , and Sequence is indicated by shaded silver.

[0100] for example, In code sequence If you need, It can be configured as follows. In this disclosure, the effectiveness of the method and device proposed in this disclosure can be evaluated by considering the 5G-NR code sequence.

[0101] By evaluating the quality of polarized separated channels through channel synthesis and separation, data is transmitted to highly reliable separated channels, and the received signal obtained through the channel is Based on this, the transmitted message can be estimated through an appropriate decoding method. Successive cancellation (SC) decoding is based on the following decision function. Based on this, the source bits are sequentially estimated one bit at a time. Estimation of SC decoder for is as shown in mathematical formula 1 below.

[0102] [Mathematical Formula 1]

[0103]

[0104] At this time, the decision function is as shown in mathematical formula 2 below.

[0105] [Equation 2]

[0106]

[0107] The above SC decoder makes a hard decision on the binary bit value according to the above decision function when estimating each bit, whereas the SCL decoder continuously Maintain a list of decryption paths for each dog and in the last step This method selects the path with the highest likelihood among the dog paths. The list of candidate paths is managed as follows.

[0108] The number of candidate paths in each sequential bit decoding step is Increasing by dog, and among these, the one with high likelihood (or low path metric) The dog path is selected and the next bit is processed. The surviving bit is decoded. Among the paths, the path with the highest likelihood is selected and the corresponding codeword is estimated. By utilizing cyclic redundancy check (CRC) or parity check (PC) codes in conjunction with these, the error correction and detection capabilities of the code can be significantly enhanced. 5G-NR considers different concatenation codes depending on the message length. This is described in detail below.

[0109] The encoding process of polar codes

[0110] Figure 4 is a diagram illustrating the encoding process of a polar code.

[0111] Figure 4 is an uplink transmission system model considering 5G-NR encoding, and illustrates the encoding chain of 5G polar codes.

[0112] Referring to FIG. 4, the encoding chain of a 5G polar code may include the following operations.

[0113] ① Code block segmentation (Only uplink (conditionally)))(410),

[0114] ② Mother code configuration (both UL, DL)

[0115] ③ CRC encoding (CRC encoding; (both UL, DL))(420),

[0116] ④ Input bits interleaver (only DL)

[0117] ⑤ Subchannel allocation and PC bits calculation (both UL, DL) (430)

[0118] ⑥ Polar encoding (both UL, DL) (440)

[0119] ⑦ Sub-block interleaver (both UL, DL) (450)

[0120] ⑧ Rate-matching (both UL, DL) (460)

[0121] ⑨ Channel interleaver ((Only UL))(470)

[0122] ⑩ concatenation (if needed) (480)

[0123] Vector in Fig. 2 (405) is the length is a message vector. If the message is long depending on the encoding parameters, the vector can be segmented into two sub-message vectors. If segmented, each sub-message vector (415) are concatenated before being modulated after undergoing the encoding process independently. The segmented length is In vector (415) is Bit CRCs are concatenated to produce a length of In vector (425). At this time, the target code rate and the actual code length to be transmitted (effective code length) By mother code length This is decided, and the length is In source vector (435) The positions of my information bits, fixed bits, parity bits, and CRC bits are determined. After that, the vector (435) is a codeword through polar encoding (440). ( Is (Inner product on the top), and the subblock interleaver (450) divides this codeword vector into 32 subblocks and then interleaves them in block units.

[0124] The length This output sequence (455) is the input of the code rate matching circular buffer (460), and the circular buffer selects one of the three modes (puncturing, shortening, repetition) that satisfies the condition and adjusts the length. Codeword that matches (465) is printed. For example, the hole is Applies when the last of the circular buffer Send only dog ​​bits (first (Does not transmit dog bits), the shortcut is It is used in the first Just send the dog bits (last (Does not transmit dog bits), repeats When the first ( ) additionally transmits bits.

[0125] Afterwards, the bits are rearranged again through channel interleaving (470), which is bit-by-bit interleaving, and this output If there is no division, it becomes the input of the modulator. If there is division, it becomes the output vector through the concatenation (480) process. (485) is the input of the modulator, and at this time the vector (If there is no division ) is binary data after the encoding process.

[0126] The modulator considers BPSK (binary phase shift keying) modulation unless otherwise specified, but the present invention includes the application of higher order modulation such as QAM (quadrature amplitude modulation). Modulation vector is then passed through the channel to be received signal vector This is the number of blocks in the channel. We assume both an in-block fading channel and an additive white Gaussian noise (AWGN) channel.

[0127] Below, the operations included in the encoding chain of the polar code are described in detail.

[0128] ① Code block segmentation (410)

[0129] The input is of size In vector (405), the output is of size In vector (415). Segmentation is not performed in Downlink (DL). ( : segmentation indicator), conditional segmentation is performed only for uplink control information (UCI) of sufficiently long length in uplink (UL) ( for UL (conditionally)). Parameters for which sign block segmentation is performed. The conditional expression is as shown in mathematical expression 3.

[0130] [Equation 3]

[0131]

[0132] In the division step, the information block is divided into two sub-blocks, an independent encoding process is performed for each sub-block, and then the two vectors are concatenated (480) before modulation. In the example of the present disclosure, in the case of a single block ( ) is mainly assumed and explained.

[0133] ② Mother code configuration (both UL, DL)

[0134] Transmitted message length (If there is no message splitting , if split ) and target code rate Based on the actual transmission codeword length is determined. At this time, the length Length is reduced through rate-matching techniques (460) such as puncturing, shortening, and repetition from the human parent code. Match it. At this time can be expressed as mathematical formula 4 below.

[0135] [Equation 4]

[0136]

[0137] Above is 10 (UL) or 9 (DL), is 5 (both UL, DL). Also ( ; is the number of CRC bits). However, to avoid applying excessive levels of puncturing or shortening, ( ) in this case Decide by

[0138] for example, In the case of the sign, since If we substitute this into the above mathematical equation 4, That is, the length of the parentheses is 2 6 =64. Instead of puncturing (or shortening) 58 bits from the parent polar code of length 128, 6 bits are repeatedly sent from the parent polar code of length 64. If the length of the parent polar code is N>E, the parent code is of length is punched (or shortened) for transmission of the code word. Back perforation, If so, it will be shortened.

[0139] Both puncturing and shortening transmit all but a portion of the parent code bits. The pattern of bits not to be transmitted is determined by a sub-vector of the output vector of the sub-block interleaver. In the case of puncturing, since the receiver has no information about the untransmitted bits of the parent code during decoding, the LLR of the corresponding bits is set to 0 and decoding is performed. The punctured bits change the channel polarization tendency, and in the u-domain, capacity-0 occurs, resulting in meaningless bits for data transmission. The set of indices of the punctured bits is called the puncturing pattern, and the set of indices of the source bits that are capacity-0 is called the incapable pattern. As will be described in detail later, when the number of punctured bits is U, the puncturing pattern is a sub-vector that includes the first U bits of the output vector of the sub-block interleaver.

[0140] ③ CRC encoding (CRC encoding; (both UL, DL)) (420)

[0141] The input is of size In vector (415), the output is of size In vector (425) is. is the length of the CRC code. CRC encoding is performed on both UL and DL, and the message length ( ) uses different CRC parity lengths. Specifically, very short UCIs (i.e., ) does not use CRC. Short-length UCI (i.e., ) contains a 6-bit CRC, a medium-long length UCI (i.e., ) uses an 11-bit CRC. DL uses a 24-bit CRC to improve error detection capability.

[0142] ④ Input bits interleaver (only DL)

[0143] The input is of length In vector , the output is of length In vector This bit interleaving distributes the CRC bits, and by determining whether there is an early decoding failure based on some of the forward-placed CRC bits, the decoding complexity can be reduced. This interleaver is only applied in the DL and is not used in the UL. Unlike the base station with high processing power, mobile devices have low processing capacity, so the decoding complexity is reduced by early decoding termination based on the distributed CRC.

[0144] ⑤ Subchannel allocation and PC bits calculation (both UL, DL) (430)

[0145] The input is of length In vector (or )(425), the output is of length In vector (435) is. The dog's message and CRC bits A parity-check (PC) bit is inserted ( ) and the rest ( ) bits are fixed to 0. Specifically, in 5G-NR, the length In code sequence A fixed bit set based on , information set This is decided.

[0146] As shown in Fig. 3, the code sequence of 5G-NR is the maximum code length Polar code sequence in which bit indices are sorted in ascending order of reliability for the polar codes as, is the source bit index. Referring to Figure 3, the top left is (e.g. '0'), the bottom right (for example, '1023') is the bit corresponding to . In reality, it varies depending on channel status code modification, etc., but it is a list of the indices of each bit channel in ascending order of reliability and is used as a priority for information bit selection.

[0147] The length In code sequence silver am. silver As a sub-sequence of , The index in A sequence in which smaller elements are extracted sequentially. For example, a code sequence with N = 128. silver It is a sequence in which bits whose index is less than 128 are sequentially extracted. Is It is a sequence in which bits whose index is less than 256 are sequentially extracted. silver It becomes a sub-sequence that extracts elements whose index is less than 512. First, The decision-making method is summarized below.

[0148] 1) Pre-freezing: is called a pre-freezing set, and is a fixed bit set first. Include in. is the output sequence by the subblock interleaver, and when punctured , when shortened am.

[0149] 2) Extra-freezing: is called an extra-freezing set, is determined by the mathematical formula 5 below and performs the addition-fixing process only when perforating. When shortened .

[0150] [Equation 5]

[0151]

[0152] 3) Reliability freezing: is called a reliability freezing set.

[0153] The capacity becomes 0 due to the perforated code bits. The bits of the domain are called incapable bits, and for this reason, it is desirable to freeze them first. The set of indices of these bits is called the pre-freezing set. It is expressed as . This is the capacity pattern in the above '② Mother code configuration (both UL, DL)' is the same as ( ) These bits cannot be transmitted reliably, so they are transmitted with a fixed value of 0 (not used for data transmission).

[0154] On the other hand, even if the capacity is not reduced to 0 by the bits being punched out, it becomes relatively more vulnerable. Bits are generated. For the perforation of these bits, 3GPP 5G-NR provides an index according to the number of bits to be perforated. All below Fix additional bits. Set The composition conditions are as shown in Table 1 below.

[0155]

[0156] In the reliability freezing stage, Except for the index of The first of We additionally fix the dog bits, and their index set is is. Therefore, It is a three-stage After the decision, the remaining Data is transmitted by placing information bits, CRC bits, and parity-check (PC) bits in the bit. Among the dog bits The dog's bits It is used as a single parity bit of the domain, ( : least-reliable PC bit count, : Information set Corresponding to the bits contained in (in the generation matrix The minimum number of PC bits is the number of 1s in the th row. This improves the performance of concatenated codes containing polar codes. Specifically, Located at the very front of Use the dog as a PC bit. After that, the bit with the lowest weight is located at the back. Use the dog as an additional PC bit.

[0157] Figure 5 is a diagram showing an example of a method for allocating a separate channel according to the length of an uplink control information (UCI) message.

[0158] In 5G-NR, the short uplink control information (UCI) length ( ) only Use bits ( Back side ). (a) of Fig. 5 This illustrates the case, in which case, is. (b) of Fig. 5 This illustrates the case, in which case, am.

[0159] ⑥ Polar encoding (both UL, DL) (440 in Fig. 4)

[0160] The input is of length In vector (435 in Fig. 4), the output is of length In vector (445 in Fig. 4). Vector (435 in Fig. 4) and (445 in Fig. 4) The relationship between the generator matrix is defined by, ( )am.

[0161] ⑦ Sub-block interleaver (both UL, DL) (450 in Fig. 4)

[0162] The input is of length In vector (445 in Fig. 4), the output is of length In vector (455 in Fig. 4). The encoded bits of the dog are interleaved in sub-block units as illustrated in Fig. 6 prior to rate-matching (460).

[0163] Figure 6 is a diagram illustrating a subblock interleaver.

[0164] Specifically, vector is the length After being divided into sub-blocks, they are interleaved by the following mathematical formula 6 ( since (is an integer).

[0165] [Equation 6]

[0166]

[0167] Referring to Fig. 6, the subblock interleaver sequence It can be seen that is (0,1,2,4,3,5,6,7,8,16,9,17,10,18,11,19,12,20,13,21,14,22,15,23,24,25,26,28,27,29,30,31).

[0168] ⑧ Rate-matching (both UL, DL) (460 in Figure 4)

[0169] The input is of length In vector , the output is of length In vector (465 in Fig. 4). Rate matching is performed by a circular buffer as illustrated in Fig. 7, and three rate matching techniques are being considered in 5G-NR. Since rate matching determines the bits to be transmitted, it is also called bit selection, and one of the following operations is performed through bit selection: puncturing, shortening, or repetition.

[0170] - Puncturing: And It applies when the bits to be transmitted are is determined by , and the vector The first of Select excluding the bits of the dog.

[0171] - Shortening: And It applies when the bits to be transmitted are is determined by , and the vector The last of Select excluding dog bits.

[0172] - Repetition: It applies when the additional bits are selected. is decided by

[0173] ⑨ Channel interleaver ((Only UL)) (470 in Figure 4)

[0174] The input is of length In vector (465 in Fig. 4), the output is of length In vector (475 in Fig. 4). Vector is interleaved bit by bit before performing modulation. (475 in Fig. 4). The channel interleaver has a right-angled isosceles triangular structure as shown in Fig. 8.

[0175] Figure 8 is a diagram illustrating a triangular interleaver used as a channel interleaver.

[0176] In Fig. 8, one of the triangle interleavers used as a 5G-NR UL channel interleaver is This case is illustrated, and can be divided into an element (800) in which a bit value is input and an element (Null) (810) in which a bit value is not input.

[0177] Triangular interleaver is applied to improve the error rate performance of high-order modulation (e.g., 16QAM, 64QAM) and can be used in UL. The length of one side of the channel interleaver Is is determined as the minimum integer that satisfies (i.e., ) The input sequence is input row by row, and the output sequence is read column by column starting from the leftmost column. Triangular interleaver The element entered in row i, column j ( If you express it as a formula, it is as shown in the mathematical formula 7 below.

[0178] [Equation 7]

[0179]

[0180] At this time The triangle interleaver has been adopted as the UL channel interleaver for 5G-NR due to its good performance in various code parameters.

[0181] Encoded data transmission over block fading channels

[0182] (1) Coding over fading channels

[0183] A block fading channel (BFC) is a convenient approximation model for slowly varying fading channels, and is particularly relevant to wireless communications involving slow time-frequency hopping (e.g., cellular networks and wireless Ethernet).

[0184] Figure 9 is a drawing showing a block diagram of a block fading transmission and reception for transmission of encoded data.

[0185] First, referring to (a) of Fig. 9, the source vector is encoded as a codeword vector , and then pass the received signal vector through the block fading channel after modulation. is obtained. If this is expressed as a formula, it is as follows: Mathematical Formula 8.

[0186] [Equation 8]

[0187]

[0188] One codeword corresponds to one homogeneous channel coefficient Unlike the situation where a codeword passes through a fading block having different channel characteristics, it can be assumed that a single codeword is transmitted through several (among them, a small number) fading channels having different channel characteristics. Fig. 9 (b) illustrates a single block coding type in which a codeword is transmitted through a single block, and Fig. 9 (c) illustrates a multiple block coding type in which a codeword is intentionally divided and transmitted through several blocks.

[0189] The multiple block coding type illustrated in (c) of Fig. 9 may include, for example, intra-slot frequency hopping (i.e., one codeword is divided into two different resource blocks and allocated for transmission) and resource allocation type (i.e., one codeword is divided into four or more different resource blocks and allocated for transmission). In this case, as illustrated in (d) of Fig. 9, different resource blocks are sufficiently far apart from each other so that their channel coefficients It is assumed that the channels are independent and that the channel characteristics are homogeneous within the resource block.

[0190] The optimal code design problem in a block fading channel is different from the optimal code design problem in an additive white Gaussian noise (AWGN) channel or a flat fading channel. The decoding performance of a channel code in an AWGN channel is determined by the minimum distance (minimum distance, ) is affected, and in the high SNR (signal-to-noise power ratio) region, as shown in the mathematical expression 9 below. class ( is approximated as a function of the number of codewords having Hamming weight.

[0191] [Equation 9]

[0192]

[0193] However, the decoding performance in block fading channels is limited by the minimum block-wise Hamming distance ( )) is affected. All possible extreme signs Dog codeword vector (every A collection of fields: (codebook)) and About is defined as in mathematical equation 10 below.

[0194] [Equation 10]

[0195]

[0196] thus, Although this has excellent performance in high AWGN channels, is small and may have poor performance in block fading channels. Diversity order ( ) is defined as the absolute value of the slope of the SNR-block error rate graph in the high SNR region (as shown in Fig. 12), and if expressed as a formula, it is as shown in Mathematical Expression 11 below.

[0197] [Equation 11]

[0198]

[0199] When performing maximum likelihood (ML) decoding, Although ML decoding is the best in terms of decoding performance, it is generally impossible to implement or the complexity is so high that it is difficult to apply practically. Therefore, even if a commonly used SC (or SCL) decoder is used, A method to achieve this is needed. The singleton-like bound provides an upper bound on the maximum diversity order that a channel code can achieve depending on the code rate, which can be expressed as a formula in Equation 12 below.

[0200] [Equation 12]

[0201]

[0202] If the number of fading blocks is In a block fading channel, the maximum possible diversity is If you want to secure (i.e., ), the maximum theoretically achievable code rate is In addition, it is possible to secure 'Diversity-2' (i.e., ) The maximum code rate is am.

[0203] (2) Diversity evaluation method based on Boolean approximation

[0204] For diversity evaluation, the block fading channel can be approximated as shown in Equation 13 below.

[0205] [Equation 13]

[0206]

[0207] is the fading channel coefficient It represents a fading probability variable approximated to 0 or 1, and specifically, 0 refers to a fading state and 1 refers to a non-fading state. of Although the Boolean approximation to Rho may result in information loss, it remains a suitable assumption for representing the diversity order. Before evaluating the diversity of source bits through the block fading channel approximation, we examine the check node (CN) and variable node (VN) operations in the genie-aided SC decoding process.

[0208] First, an LLR update corresponding to a channel downgrading is performed in CN, and an LLR update corresponding to a channel upgrade is performed in VN. polarization stage- ( The domain's stage is 0, The stage of the domain )at When LLR corresponding to the th index is expressed as a formula, LLR update in CN and VN is as follows: Mathematical expressions 14 and 15.

[0209] [Equation 14]

[0210]

[0211] [Equation 15]

[0212]

[0213] In other words, when performing CN operation, the output LLR is the product of the two input LLRs. It is determined by the operation, and the output LLR in the VN operation is determined by the addition of the two input LLRs. First, for the two input operations above, the input message and A Boolean fading variable corresponding to and and output message The corresponding fading variable Let's say. In this case The operation of the fading variable corresponding to the operation is And, The corresponding fading variable operation is can be approximated by . Following the SC decoding process, a fading function can be derived for all messages and LLR calculations, and the presence of full diversity can be determined through this fading function. For example, If given as has full diversity. The calculation process can be summarized as follows.

[0214] 1) All code word bits A single boolean variable for is assigned.

[0215] 2) When performing CN (VN) operation at each stage on a bipartite graph, a Boolean AND (OR) operation is performed.

[0216] 3) After performing all the Boolean fading function updates, the source bits The Boolean fading function is determined.

[0217] At this time, in the bipartite graph After the CN / VN update, the fading Boolean probability variables of the source bits can be expressed as a sum of products. First, let's discuss the full diversity of the fading function from the perspective of Boolean function representation. First, let's consider the average SNR of the Rayleigh fading channel corresponding to the Boolean fading variable. And it has the same relationship as the mathematical formula 16 below.

[0218] [Equation 16]

[0219]

[0220] At this time, the Boolean function of the message during the decryption process Ramen, the probability of fading is This is diversity will have. Given Diversity for block fading A message and source bit having 'full diversity' is said to have 'full diversity'.

[0221] The diversity of each source bit can be evaluated by the diversity of the Boolean fading function calculated on the source bit. On the other hand, the diversity of the entire code is affected by the nature of SC decoding. If a specific bit enters a fading state during the decoding process, the entire decoding will enter a fading state. Therefore, the diversity of the entire code can be expressed as the product of the Boolean fading functions of all information bits. Decoded fading function of the code Is It can be written as, and if The backside code has full diversity. The full diversity of the source bits or decoded message can be easily determined by examining the truth table.

[0222] Source Bit Boolean fading function The weight of the corresponding truth table (the number of 1s) go If you are satisfied with has full diversity. For Boolean functions without inverted literals, the truth table weight (the number of 1s) and diversity are generally positively correlated. Therefore, the truth table weight can be used as an indicator for diversity evaluation and system design.

[0223] Code rate matching method and polar encoding BICM system

[0224] FIG. 10 is a drawing showing an example of a block diagram of a polar coded BICM system in a wireless communication system.

[0225] For example, in 5G-NR, a sub-block interleaver satisfying binary domination is used for flexible circular buffer code rate matching (the detailed operation of the sub-block interleaver is the same as that of the sub-block interleaver (450) illustrated in FIG. 4 or described in FIG. 6).

[0226] Codeword vector replaced by subblock interleaver From the front, depending on the code rate matching mode The bit is perforated or from the back The bits can be shortened. Afterwards, the codeword vector with the code rate matched After being interleaved bit-by-bit by a triangle interleaver, it is modulated and passes through M fading channels (fading channel 1, ..., fading channel M). The triangle interleaver is a pseudo-random interleaver, and its structure is simple, easy to implement in hardware, and has stable performance in overall code parameters.

[0227] Fig. 11 is a drawing showing an example of a block diagram of a polar coded BICM system in a wireless communication system.

[0228] Figure 11 illustrates a transmission method of polar codes that systematically guarantees diversity by considering the allocation pattern of codeword bits to a fading channel. This method utilizes a code designed for a block fading channel under specific conditions, while aligning the information bits of the code with high decoding diversity (e.g., full diversity) through appropriate interleaving. This allows codeword bits to be allocated according to the fading block allocation pattern found by the search algorithm. This improves block fading channel performance while maintaining AWGN performance.

[0229] First, we evaluate the diversity of source bits in SC decoding with low complexity through a Boolean approximation of the fading function. This allows for a simple evaluation of bit and code diversity for any arbitrary codeword bit allocation pattern (i.e., interleaving sequence), and facilitates the prediction of the slope of the SNR-block error rate graph (i.e., the diversity order).

[0230] Next, for polar codes that are not rate-matched, if a code sequence that satisfies the symmetry property is used as an interleaver, It is shown that diversity-2 is guaranteed up to a code rate of 0.5 (i.e., the theoretical limit) in a block fading channel. In this case, the symmetry property can be realized as a setup for this, as shown in Fig. 11, by a combination of (rate-matching interleaver, channel interleaver) = (identity interleaver (1100), code sequence interleaver (i.e., performing bit grouping) (1110)) or (code sequence interleaver, identity interleaver).

[0231] Furthermore, the method of Fig. 11 A common block fading channel, among which a small number of We developed a search-based diversity interleaver search method, and allocated code bits based on the searched interleaver to achieve diversity- While guaranteeing the code rate- It shows performance that achieves or approaches . In addition, This includes a method for adjusting codeword allocation patterns using auxiliary sequences to accommodate punctured / shortened polar code transmissions in block fading channels. Through the above detailed techniques, the system achieves performance similar to that of a 5G-NR BICM system in an AWGN channel, while achieving performance gains due to diversity gain in a block fading channel.

[0232] The 5G-NR channel interleaver illustrated in Figure 10 above performs random bit-level interleaving, and therefore does not guarantee diversity. Furthermore, its structural vulnerabilities, coupled with the interplay of the sign parameters and the triangular interleaver parameters, can lead to performance degradation.

[0233] In addition, the diversity transmission method illustrated in Fig. 11 is a transmission method that guarantees full diversity. It may be an interleaver specialized only for low code rates. That is, the method illustrated in Fig. 11 cannot guarantee consistently high diversity at medium-high code rates. Therefore, an interleaver design technology that maintains or guarantees high diversity up to high code rates (higher diversity for wider code rates) is needed.

[0234] Second, the diversity transmission method illustrated in Fig. 11 has an overhead problem in storing all optimal interleavers (or code bit allocation patterns) obtained by the search-based interleaver design. Specifically, the code length ( ), degree of perforation / shortening ( ), number of fading blocks ( ) when considering all combinations of individual optimal interleavers, the number of cases is very large. Furthermore, Regarding the proposed auxiliary sequence-based allocation pattern for polar code transmission in an in-block fading channel, Diversity performance cannot be guaranteed in a general block fading channel. Therefore, in this disclosure, various We propose a systematic interleaver design method that guarantees high diversity (especially diversity-2) up to high code rates while supporting rate-matching polar codes.

[0235] Figure 12a is a diagram illustrating a modified SNR (signal noise rate)-BLER (block error rate) graph according to the diversity order.

[0236] The block error rate in the high SNR region in a block fading channel can be obtained by modifying Equation 11. It can be expressed as follows. For example, diversity order The decoding performance of the human code is improved by one decade when the SNR increases by 10 dB. While the error rate decreases (by 1 / 10), The decoding performance of the human code has been around for 4 decades ( 1 / 10 4 ) reduces the error rate. Since the gain from increasing diversity is generally large when the base diversity order is low, achieving full diversity is important, but ensuring a minimum diversity of 2 for a wider range of code parameters is also very important.

[0237] Figure 12b is a diagram showing the results of simulating the decoding diversity order that can be achieved depending on the code rate.

[0238] Figure 12b is When d is used, it represents the decoding diversity order according to the code rate. The theoretically achievable maximum diversity order (Theoretical bound) (d c ) is the Singleton-like bound formula described in Equation 12. is determined by, for example, In this case, we can have diversity-4, which is full diversity up to 1 / 4, where the code rate is 1 / M. In addition, if the code rate is The present disclosure proposes a coded diversity transmission method that can have diversity-2 in a wider code rate range while securing diversity similar to conventional diversity.

[0239] Punctuation and shortening are rate-matching methods that do not transmit some of the codeword bits, as described in Fig. 4, and the pattern of these bits is a sub-vector of the output vector of the sub-block interleaver. Since the receiver does not have probability information about the untransmitted codeword bits during decoding of the punctured polar code, the decoding is performed by setting the log-likelihood ratio (LLR) of the corresponding bits to 0. The punctured bits change the channel polarization tendency (compared to the sole polar code), In the (source) domain, the channel capacity becomes 0, resulting in meaningless bits for data transmission. At this time, the set of indices of the bits being punctured is called a puncturing pattern. The set of indices of source bits for which the corresponding channel capacity is 0 is called the incapable pattern. It is written as . The number of perforated bits is When you say, always If the perforation pattern satisfies binary domination, It also holds true.

[0240] The subblock interleaver employed in 5G-NR satisfies binary domination, with bits being punctured in the interleaver order. An example of this is illustrated in Figure 13 below.

[0241] Figure 13 is a drawing showing an example of a transmission block diagram of a perforated polar code.

[0242] Fig. 13 is The block diagram of the transmission of a perforated polar code is shown. The subblock interleaver in this example divides the 16 codeword bits (d) into 8 subblocks in units of 2 bits. This shows an example of interleaving with a sub-block interleaver sequence (this is different from the sub-block interleaver of 5G-NR, but similar in that the sub-block interleaver sequence satisfies binary domination). Since the applied sub-block interleaver sequence satisfies binary domination, the puncturing pattern When a 4-bit perforation occurs, the source bits with the same index become incapable and become zero-capacity bits (i.e., ).

[0243] Figure 14 is a drawing showing an example of a transmission block diagram of a shortened polar code.

[0244] Fig. 14 is The following shows an example of a shortened polar sign.

[0245] For the abbreviated polar code, first A set of shortening pattern indices in the domain First, determine the corresponding short bits and fix these values ​​to 0. These are bits that are not used for data transmission, like fixed bits. Then, corresponding to this short pattern, In the domain, there are bits whose values ​​are always fixed to 0, and the set of indices of these is called a 'fixed pattern'. is denoted as . Since the receiver knows perfectly that this value is 0, it attempts to decode using this as prior information. Like the punctured polar code, the shortened polar code also has a shortened pattern defined by the subblock interleaver sequence, and the last of the subblock interleaver sequence It's shortened by a bit.

[0246] Referring to Figure 14, after the codeword bits are interleaved by the rate-matching interleaver, the last The bits are shortened. Since the interleaver used at this time satisfies binary domination, am.

[0247] Figure 15 shows the code word bits of the polar code. A diagram illustrating an example where a block is assigned to a fading channel and the fading channel is fading (i.e., bits assigned to the channel are dynamically punctured).

[0248] The transmission of encoded data over a block fading channel can be simulated by dynamic puncturing of large codeword bits. Figure 15 shows the codeword bits of a polar code with a code length of 16. This shows a situation where the signal is transmitted by dividing it into a block fading channel. (For convenience of explanation, Fig. 15 omits the illustration of the subblock interleaver, code rate matching, and channel interleaver). At this time, the received signal that passed through the block fading channel It can be expressed as follows.

[0249] In this disclosure, the state of a fading block is approximated by a Boolean approximation-based diversity analysis. In this case, If you are stuck in this fading The first 8 codeword bits assigned to ( ) can be interpreted as a dynamically perforated situation. In this case, even if the subblock interleaver is not performed, the sequence always satisfies binary domination. Equivalent to becomes a dynamically incapable bit.

[0250] Similarly, fading channels Even if it is fading, it is the same becomes a dynamic capacity bit. However, in this case This is a special case. However, in general, the first of the codeword vectors interleaved by a sub-block interleaver that satisfies binary domination Dog bits on a specific fading channel is assigned, and if any one of the fading channels falls into fading, The source bits that are identical to the indices of the allocated code word bits always become dynamic capacity bits.

[0251] Therefore, when transmitting rate-matched polar codes in a block fading channel, a type of bit that cannot transmit data by dynamic capacity bits is additionally defined in addition to the zero-capacity bits (in the case of punctured polar codes) or the shortened bits (in the case of shortened polar codes). Examples of this can be illustrated in Figures 16a and 16b below.

[0252] FIG. 16a and FIG. 16b are diagrams illustrating an example of rate-matched polar code transmission through a block fading channel with a perforated (or shortened) code rate.

[0253] Figure 16a illustrates a case where fading (dynamic puncturing) occurs in fading channel 1 in a punctured code rate matching polar code transmission, and Figure 16b illustrates a case where fading (dynamic puncturing) occurs in fading channel 1 in a shortened code rate matching polar code transmission.

[0254] Figure 16a is for the perforated polar symbol. and An example of this is shown. The bits of the are the capacity bits. The remaining bits excluding these bits When allocating 6 bits each of the dog bits {3,5,6,7,8,9,10,11,12,13,14,15} to fading channels 1 and 2 ( ), this assignment sequence also satisfies binary domination.

[0255] thus The source bits with the index of become dynamically the capacity bits. That is, Source bits with indices are more likely to be zero-capacity bits. In summary, is a zero-capacity bit that cannot transmit data because the channel capacity is 0 regardless of the channel status. Depending on the channel condition, these are the bits that have the highest probability of becoming dynamic capacity bits and are therefore the bits with the lowest diversity and are vulnerable to errors during data transmission. In contrast, are bits that enable relatively robust data transmission in fading channels.

[0256] Figure 16b is and The following shows an example of a shortened polar sign. The remainder Each of the 6 bits {0,1,2,3,4,5,6,7,8,9,10,12} are divided into fading channels 1 and 2 and assigned ( , ), this assignment sequence also satisfies binary domination.

[0257] thus Source bits with indices are more likely to be dynamic capacity bits. In summary, Since data transmission is impossible because it is transmitted with a value known to the transmitter and receiver (i.e. 0) regardless of the channel status, are bits that have the highest probability of becoming dynamic capacity bits depending on the channel condition, and are therefore bits with low diversity and vulnerable to errors during data transmission. Therefore, source bits that enable safe data transmission from a diversity perspective are am.

[0258] In summary, the source bits suitable for data transmission in a block fading channel are the complement of the combination of the zero-capacity bits and the dynamic zero-capacity bits in the case of the punctured polar code, and the complement of the combination of the dynamic zero-capacity bits and the shortened bits in the case of the shortened polar code.

[0259] Below, a polar code transmission method that considers diversity and can be universally applied to various code rate matching polar codes is described.

[0260] FIG. 17 is a block diagram illustrating an example of a bit-interleaved coded-modulation (BICM) system according to one embodiment of the present disclosure.

[0261] The following describes the characteristics of the polar-coded BICM (bit-interleaved coded-modulation) system illustrated in Fig. 17.

[0262] (1) Compliance with AWGN code (sequence)

[0263] Diversity alignment is a method for aligning the information bits u (1700) of a given code (e.g., a code suitable for AWGN channels) to the intended diversity. Since the present disclosure aims to guarantee diversity of 2 or higher even at high code rates, we propose an interleaver that aligns as many information bits as possible to achieve diversity of 2 or higher. This process can essentially utilize existing codes that perform well in AWGN channels.

[0264] Additionally, code transformation can be allowed as needed without degrading the performance of the AWGN channel. This code transformation is possible through "adaptive extra-freezing based on message length," as detailed in Figure 18. Furthermore, a method for determining the level of extra-freezing based on the type of rate-matching interleaver is also described.

[0265] (2) Support for code rate matching

[0266] The present disclosure relates to a code length (1710) at rate-matching. ), level of perforation / shortening ( ), number of fading blocks ( ) to ensure high diversity by systematically allocating codeword bits to fading channels. The present disclosure does not require a search-based algorithm to find the optimal interleaver. Furthermore, the method proposed in the present disclosure can be performed without individually storing these interleavers.

[0267] (3) Bit grouping

[0268] According to one embodiment of the present disclosure, a codeword vector having a matched code rate into two groups ( can be grouped (1720). At this time, group 1 ( ) ratio ( ) may have different values ​​depending on the rate-matching interleaver type or rate matching mode (i.e., puncturing / shortening). As can also be expressed as a function of . Grouping is essential for 'diversity sorting', which makes the poor poorer by binary domination the less reliable source bits to always have lower diversity, thus increasing the likelihood that the remaining source bits will have higher diversity.

[0269] (4) Individual interleaving by group

[0270] After grouping the interleaved and rate-matched codeword vectors according to the rate-matching interleaver type, individual interleaving can be performed on each group (1730). At this time, pseudo-random interleaving can be performed on each group, and a triangular interleaver can be considered as a representative example. Group-specific interleaving can maintain performance in high-order modulation transmission of AWGN channels and maximize diversity performance.

[0271] As a result, the present disclosure can secure a 'diversity 2' region in a wide code rate region in a block fading channel, thereby achieving a large performance gain while maintaining the high-order modulation transmission performance of an AWGN channel.

[0272] FIG. 18 is a diagram illustrating an example of shortened polar code transmission over a block fading channel according to one embodiment of the present disclosure.

[0273] Fig. 18 is This is an example showing the transmission of a shortened polar code. A code sequence that satisfies binary domination with a rate-matching interleaver (1800). was taken into consideration.

[0274] 16 interleaved codeword bits ( ) are the last 4 bits by circular buffer code rate matching. is not transmitted, and the corresponding (before interleaving) codeword bits are . Therefore, the short bits are , and data can be transmitted among the remaining 12 bits excluding these bits.

[0275] However, when transmitting data over a block fading channel, fading ( Dynamic capacity bits are generated by dynamic perforation. At this time, assuming the use of a channel interleaver that satisfies binary domination, an example is the code rate matching bit. It can be assumed that is assigned to fading channel 1 (1820). In this case, source bits having such an index (i.e., ) are the worst dynamic capacity bits. That is, when transmitting a shortened polar code in a block fading channel. and the shortened bits of Dynamic capacity bits are created.

[0276] At this time, are source bits that cannot transmit data unconditionally, whereas are bits that can be selected as data depending on the code design method. Therefore, the present disclosure is a polar code sequence We aim to maximize the match (or minimize the mismatch) between the set of bits with the lowest reliability and the set of bits with the worst dynamic capacity according to the block fading channel allocation pattern. This increases the likelihood that bits with low reliability will have the worst diversity, while bits with high reliability will have better diversity.

[0277] Hereinafter, a transmission method of a BICM system according to one embodiment of the present disclosure will be described by dividing it into the following cases.

[0278] Case 1: When the rate-matching interleaver (BD interleaver) is a sign sequence interleaver.

[0279] Case 2: When the rate-matching interleaver (BD interleaver) is a sub-block interleaver

[0280] Case 3: When the rate-matching interleaver (BD interleaver) is a different type of subblock interleaver.

[0281] Case 4: When rate matching is performed by perforation, if the rate-matching interleaver (BD interleaver) is a code sequence interleaver or a sub-block interleaver.

[0282] FIG. 19 is a drawing illustrating an example of a BICM system transmission block diagram for a shortened polar code when using a code sequence with a rate-matching interleaver according to an embodiment of the present disclosure.

[0283] Fig. 19 illustrates a polar encoding system in the case of using a code sequence interleaver (1900) used for information bit selection as a rate-matching interleaver, which corresponds to case 1 described above. In particular, in the case of using a code sequence interleaver (1900), (i.e., ) illustrates a BICM transmission system that generates a shortened polar code. In this transmission environment, the system illustrated in Fig. 19 has the following characteristics.

[0284] 1) The subblock unit interleaver (450 in FIG. 4) described in FIG. 4 is replaced with a code sequence-based interleaver (1900), thereby changing the cyclic buffer code rate matching sequence. As a result, the bits corresponding to dynamic puncturing due to fading generally become the channels with the lowest reliability. Consequently, the puncturing pattern and shortening pattern differ from the existing ones.

[0285] 2) Replacing the subblock interleaver sequence used as the rate-matching interleaver with a code sequence makes it relatively easy to handle for 'diversity alignment'. Specifically, after interleaving based on the code sequence, the rate-matched sequence is simply , even if grouped and allocated as such, the source bits having the indices of the bits allocated to block 1 always have diversity-1.

[0286] FIG. 20 is a diagram illustrating fading channel allocation of polar codes when a code sequence is used as a rate-matching interleaver according to one embodiment of the present disclosure.

[0287] FIG. 20 is a drawing specifically explaining fading channel allocation for the BICM system transmission block diagram described in FIG. 19.

[0288] When using a sign sequence as a rate-matching interleaver, Vector of polar codes that are not rate-matched in a block fading channel After grouping them in a 1:1 ratio, they can be transmitted by assigning them to fading blocks 1 and 2, respectively. However, in this case, it is very difficult to design a channel interleaver (or search for a codeword bit allocation pattern) that guarantees maximum diversity up to the theoretical limit for punctured (or shortened) polar codes. The codeword index sets corresponding to groups 1 and 2 are each and the grouping ratio cast ( : effective code length, ) when Is can be determined as a function of the number of block fading channels, such as It can be determined as follows.

[0289] And, the grouped codeword vectors are each , can be expressed as . Afterwards, individual pseudo-random interleaving can be performed for each group. For example, There is identity interleaving, It can perform triangular interleaving.

[0290] Fig. 20 is An example of fading channel allocation of a shortened polar code is shown. First, among the source bits u(2000), the 4 bits to be shortened are the code sequence corresponds to the last 4 bit index of Therefore, the bits that performed the circular buffer code rate matching (2010) after the code sequence interleaving (2005) )(2015) is a bit sequence am.

[0291] And this vector cast Considering the ratio of If you group them, , This is it. And Group 1 (2020) for identity interleaving (interleaving X), For group 2 (2025), triangular interleaving (2030) is performed to assign fading blocks, and each fading block The set of indices of bits allocated to each am.

[0292] FIG. 21 is a drawing illustrating an example of a BICM system transmission block diagram for a shortened polar code when a sub-block interleaver is used as a rate-matching interleaver according to one embodiment of the present disclosure.

[0293] Figure 21 illustrates a BICM transmission system for shortened polar codes when using a subblock interleaver as a rate-matching interleaver. The subblock interleaver uses a codeword vector as described in Figure 4. The size of After dividing into 32 sub-blocks, they are interleaved in the following sequence.

[0294]

[0295] FIG. 22 is a diagram illustrating polar code fading channel allocation when a subblock interleaver is used as a rate-matching interleaver according to one embodiment of the present disclosure.

[0296] Fig. 22 is a diagram specifying a channel allocation method in the BICM transmission system illustrated in Fig. 21.

[0297] Referring to Figure 22, the ratio of codeword bits allocated to group 1 (2220) for the codeword e (2215) that has been rate matched and sub-block interleaved (2205) and rate matched (2210) Is can be decided by ( ) In addition, individual pseudo-random interleaving can be applied to each group, for example, triangular interleaving (2230 and 2235) can be performed on group 1 (2220) and group 2 (2225) respectively to prevent fading channels. can be assigned to.

[0298] In this case, the BICM transmission system for the shortened polar code has the following characteristics.

[0299] 1) Since the subblock interleaver sequence is used, the code rate matching sequence is maintained as is.

[0300] 2) However, the sub-block interleaver sequence and the code sequence have a large mismatch. Therefore, the sequence e (2215) with sub-block interleaving (2205) and code rate matching (2210) is used as is. (2220), When grouped as (2225), Source bits such as the indices of the grouped code bits can be poor dynamic capacity bits. For example, as shown in Fig. 22. Assuming a transmission situation through a block fading channel of a polar code, the bits ( ) that have undergone sub-block interleaving (2205) and then code rate matching (2210) )(2215) The first 8 bits of the bit sequence (i.e., (The code word bits grouped as ) are assigned to fading block 1 (2240) ( ) Therefore, the source bits with this index will be poor dynamic capacity bits.

[0301] but, The code sequence of 5G-NR is as follows.

[0302]

[0303] That is, the index set of the 8 bits with the lowest reliability is Assigned to the above fading block 1 (2240) and a 2-bit mismatch occurs (i.e., ) The reason why this mismatch problem is a serious problem is that Because the bits allocated to always have diversity-1.

[0304] Considering the above code sequence, There is no problem because it is included in the 8 bits with the lowest reliability in the code sequence, but is the 10th least reliable bit, and corresponds to the 17th least reliable bit. In this case, even though it is the 16th most reliable bit, the diversity becomes 1, so when grouping is performed immediately after performing subblock interleaving, bits that satisfy certain conditions may have diversity-1 early, which may significantly degrade the code performance.

[0305] Accordingly, in this disclosure, a method is proposed to ensure diversity performance through 'adaptive extra-freezing' (2100 in FIG. 21) when the sub-block interleaver is followed as is during transmission of shortened polar codes.

[0306] First, a set of indices of bits that are particularly vulnerable to fading. Defines a set The size of and, As an ordered sequence sorted in ascending order of reliability It can be expressed as a set can be determined differently depending on the type of rate-matching interleaver. Or, a set can be determined by considering at least one of the performance of the block fading channel and the performance of the AWGN channel. The set determined in this way (or ) from the adaptive extra-freezing set: ) can be configured.

[0307] in other words, Is (or ) is determined by a subset (or subsequence), and the size of this subset is (or ) is dependent on. When it's small And, When it's big As described above, When the is small, all possible vulnerable bits are supplemented and fixed. As the size increases, the relatively less vulnerable bits are excluded from the supplementary fixed set and used as bits for data transmission. At this time, the threshold for releasing each element Define additionally. For example, Go threshold If it is smaller than am. Go threshold Greater than or equal to If it is smaller than That is, As it grows, it crosses the threshold and each time it does Reduce the size by 1. go If it's bigger than am.

[0308] Accordingly, a method for supplementing the case of using a sub-block interleaver as a rate-matching interleaver as shown in FIGS. 21 and 22 is described below in FIG. 23.

[0309] FIG. 23 is a drawing illustrating an example of a BICM system transmission block diagram for a shortened polar code when a sub-block interleaver satisfying arbitrary binary domination is used as a rate-matching interleaver according to one embodiment of the present disclosure.

[0310] Figure 23 illustrates a BICM transmission system for shortened polar codes using a subblock interleaver modified with a rate-matching interleaver. Figure 23 illustrates a system for addressing potential problems that may arise when the subblock interleaver of Case 2 described above is directly followed. The system model is similar to Figure 22, but is characterized by performing a different type of subblock interleaving than the subblock interleaving illustrated in Figure 22 prior to rate matching.

[0311] In Fig. 23, we propose a different type of sub-block interleaver design with the following two approaches.

[0312] ① Use of a subblock interleaver sequence similar to the code sequence

[0313] In the subblocks used in Fig. 22 described above, a method of always dividing and interleaving them into 32 subblock units for various code lengths is considered for implementation convenience and low processing time. Similarly, Fig. 23 considers a method of modifying the interleaving sequence of the subblock interleaver while maintaining the number of subblocks to 32. The subblock interleaver sequence can be modified in a direction that minimizes the mismatch between the subblock unit interleaver sequence and the code sequence, or the subblock interleaving sequence can be determined by reflecting the Hamming weight or the reliability of the polar code while satisfying binary domination. Below is an example of such a modified subblock interleaver sequence.

[0314]

[0315] ② Use of a subblock interleaver sequence with adaptive subblock size according to length

[0316] Length of mother's sign ( )go is defined as, Interleaving can be performed by dividing the codeword vector into 32 subblocks regardless of the number of blocks. This is an efficient way to reduce processing time, but In this case, since 32 bits are grouped into one subblock and interleaved in block units, when considering the combination with the invention technology, there is a high possibility that source bits with high Hamming weights (or source bits with high reliability) will be forced to become the worst dynamic capacity bits. Therefore, as one method to alleviate this, subblock interleaving, in which the number of subblocks varies depending on the code length, can be considered.

[0317] In the case of subblock interleaving described in Fig. 22, the size of the subblock is independent of the code length. was set to (i.e., In this case, the subblock size is 512 / 32=16, In this case, the subblock size is 1024 / 32=32), When the subblock size is set to a value smaller than 32 (e.g., 8), the subblock size can be set to a value smaller than the existing subblock size for other code lengths. (Or, the subblock size can be set to a value larger than the existing number of subblocks.) This setting can prevent bits with high Hamming weight from becoming poor dynamic capacity bits. In addition, as an embodiment, and the size of individual subblocks is The code length is , as a sub-block interleaver sequence. In code sequence can be used. For example, In subblock interleaver sequence can be utilized.

[0318] In the case of Case 3, similar to the above cases, the vector undergoes subblock interleaving and code rate matching. cast Group them as follows. At this time, Is can be determined. In addition, individual pseudo-random interleaving can be performed for each group, for example, triangular interleaving can be performed for both group 1 and group 2. In addition, similar to case 2, 'adaptive append-fixing (2330)' can be performed to prevent the weak bits of the shortened polar code from becoming information bits. At this time, the index set of bits to be appended-fixed can be defined in advance, and the information dimension (i.e., ) can also be defined in advance.

[0319] FIG. 24 is a drawing illustrating an example of a BICM system transmission block diagram for a perforated polar code according to one embodiment of the present disclosure.

[0320] Figure 24 shows a BICM transmission system for rate-matching interleavers satisfying various types of binary domination, such as the code sequence interleaver, sub-block interleaver, and modified sub-block interleaver described in cases 1 to 3 above.

[0321] Unlike the shortened polar code, the punctured polar code is the first bit of the circular buffer when matching the code rate. Excludes the bits of the dog from transmission. However, the vector is the same as in the above cases. (2415) (2420) and (2425) is grouped. At this time, the ratio of code word bits allocated to group 1 (2420) Is can be determined. In addition, individual pseudo-random interleaving can be applied to each group. For example, triangular interleaving or block interleaving can be performed on groups 1 (2420) and 2 (2425), respectively. In addition, in the case of punctured polar codes, the 5G-NR additional fixation rule is followed and separate additional fixation can be omitted. Depending on the situation, additional fixation can be applied in combination with other technologies to improve fading channel performance when additional optimization is desired.

[0322] Below, we present various experimental performances of the method proposed in this disclosure. For the experiments, the mother code length ( ) We considered both SC decoding and CRC-aided SCL decoding. In the case of CRC-aided SCL decoding, , In block fading channels, BPSK (binary phase shift keying) modulation was considered to focus on the effect of the designed interleaver, and under AWGN channels, the performance of low-order modulation (BPSK / QPSK) is the same regardless of the interleaver type, so the performance of high-order modulation of 16 / 64QAM was compared.

[0323] FIG. 25a, FIG. 25b and FIG. 25c illustrate the use of a code sequence interleaver as a rate-matching interleaver in a block fading channel according to an embodiment of the present disclosure, and parameters for grouping. go BLER of the shortened polar sign in case of = 10 -3 Figures 25a, 25b, and 25c are diagrams showing the results of the required SNR [dB] to achieve the block fading channel. BLER during SC decoding of short polar codes The required SNR [dB] to achieve this was compared. At this time, the method proposed in this disclosure used a code sequence interleaver as a rate-matching interleaver, and the parameter for grouping go This is the performance in this case.

[0324] Fig. 25a is =2, and the experimental results show that it consistently has superior decoding performance in a very wide code rate range compared to 5G-NR. Specifically, BLER in the code It has a performance gain of about 5 dB or more based on the SNR standard.

[0325] Figure 25b is =3, Fig. 25c is =4, and it can be seen that the designed interleaver consistently has superior decoding performance compared to the prior art for various code parameters and fading channel transmission situations.

[0326] FIG. 26a and FIG. 26b illustrate a case in which a sub-block interleaver is used as a rate-matching interleaver in a block fading channel according to an embodiment of the present disclosure, and adaptive addition-fixing is applied, and the BLER of the shortened polar code is 10. -3 This is a diagram showing the results of the required SNR [dB] achieved.

[0327] Figures 26a and 26b and SC decoding performance was considered. Figure 26a is , Fig. 26b In this case, it can be seen that the method proposed in this disclosure has excellent decoding performance in a wide code rate range.

[0328] FIG. 27 is a diagram showing the results of comparing the BLER performance of shortened polar codes according to a decoding method in a block fading channel according to one embodiment of the present disclosure.

[0329] In Fig. 27, the existing method (Triangular) is indicated by a dotted line, and the proposed method in this disclosure is indicated by a solid line. In addition, the values ​​in parentheses are or It represents.

[0330] Referring to Figure 27, Sign (sign rate = 0.50) and The code (code rate = 0.53) was used to compare SC decoding performance. The code (code rate = 0.58) was compared with the CRC-aided SCL decoding performance. In particular, in the case of the CRC-aided SCL decoding performance, it can be seen that the proposed method in this disclosure has a higher diversity order (2) than the existing method, resulting in a lower error rate and thus a greater performance gain.

[0331] FIG. 28a and FIG. 28b are diagrams showing the results of comparing the high-order modulation performance of a shortened polar code in an AWGN channel according to one embodiment of the present disclosure.

[0332] Figures 28a and 28b BLER of short polar symbols The required SNR [dB] to achieve this is compared. Fig. 28a shows the results considering 16QAM as a higher-order modulation, and Fig. 28b shows the results considering 64QAM. In the case of the method proposed in this disclosure, the performance was evaluated by considering both the code sequence interleaver and the 5G sub-block interleaver as a rate-matching interleaver.

[0333] That is, for the Code-seq interleaver graph, the code sequence is used as a rate-matching interleaver and , and for the subblock interleaver graph, the 5G subblock interleaver is used as a rate-matching interleaver. It represents the performance in this case.

[0334] When comparing performance with 5G-NR in AWGN channels, it should be noted that when a code sequence interleaver is used as a rate-matching interleaver, the shortening pattern becomes different, so the code used for the rate-matching polar code becomes different, and the information set also becomes different.

[0335] When using a 5G subblock interleaver as a rate-matching interleaver, the shortening pattern is the same, but the method proposed in this disclosure performs additional extra-freezing, so the information set may also differ. Therefore, the results of the decoding performance experiment in an AWGN channel are as shown in Figures 28a and 28b. First, In the case of abbreviated polar symbols The performance of the method proposed in this disclosure using a code sequence as a rate-matching interleaver is somewhat degraded, but on the other hand In case of From the above, it can be confirmed that the performance of the method proposed in this disclosure is significantly improved. That is, depending on the shortening pattern, the AWGN performance superiority of the method proposed in this disclosure and the 5G-NR method is reversed and maintained similarly. In the remaining areas, for example, as shown in Fig. 28b , the method proposed in this disclosure consistently has superior performance when transmitting 64QAM.

[0336] Referring to Figures 28a and 28b, the method using a 5G subblock interleaver as a rate-matching interleaver maintains similar performance to 5G-NR technology while achieving an improvement of approximately 0.2 dB in some code parameters. Consequently, both the method using a code sequence interleaver as a rate-matching interleaver and the method using a 5G subblock interleaver maintain similar AWGN performance while achieving an improvement in some parameters.

[0337] FIG. 29 is a flowchart illustrating the operation of an electronic device according to one embodiment of the present disclosure.

[0338] In step 2900, the electronic device can perform rate matching interleaving and rate matching on the codeword bits corresponding to the polar code.

[0339] In step 2910, the electronic device can group the codeword bits on which the rate matching interleaving and rate matching have been performed into a first bit group and a second bit group including different numbers of bits.

[0340] In step 2920, the electronic device may perform channel interleaving on at least one of the first bit group and the second bit group.

[0341] In step 2930, the electronic device can assign and transmit the two bit groups on which the channel interleaving has been performed to two or more fading channels.

[0342] In one embodiment, the electronic device may group the codeword bits subjected to the rate matching interleaving based on binary domination and the rate matching thereof into a first bit group and a second bit group.

[0343] In one embodiment, a bit-wise interleaver based on a polar code sequence may be used for the rate-matching interleaving. In one embodiment, the code sequence may represent the indices of the separated channels by ordering them based on reliability and satisfying binary domination.

[0344] In one embodiment, some of the codeword bits may be punctured or shortened to achieve the code rate matching.

[0345] In one embodiment, the electronic device may extra-freeze at least one source bit corresponding to the code bits on which the interleaving and code rate matching are performed, when a sub-block-based interleaver is used for the rate matching interleaving and some of the code bits are punctured for the rate matching.

[0346] In one embodiment, the at least one additionally fixed source bit may be determined based on at least one of a type of interleaver used for the rate-matching interleaving, performance of the fading channels, or performance of an AWGN channel.

[0347] In one embodiment, when a sub-block interleaver is used for the rate matching interleaving, the sub-block interleaver may be related to a polar code sequence.

[0348] In one embodiment, when a sub-block interleaver is used for the rate-matching interleaving, the sub-block interleaver may be based on a sub-block interleaver sequence that takes into account at least one of binary domination, Hamming weight, or reliability of polar codes.

[0349] In one embodiment, when a subblock interleaver is used for the rate matching interleaving, the length of a subblock of the subblock interleaver may be determined based on the length of the parent code.

[0350] According to one embodiment, the present disclosure proposes a method of an electronic device that classifies codeword bits into two non-uniform groups, performs interleaving on each, divides them again into M blocks, modulates them, and transmits them through M fading blocks (resources). In one embodiment, a rate-matching interleaver is used when generating codeword bits, and the rate-matching interleaver may use at least one of a code sequence interleaver or a sub-block interleaver. In one embodiment, the electronic device may modify a code by performing shortening using a circular buffer. In one embodiment, when a sub-block interleaver is used as the rate-matching interleaver, adaptive additional fixation may be performed correspondingly.

[0351] In one embodiment, when a subblock interleaver is used as the rate matching interleaver, a subblock interleaver sequence corresponding to a code sequence may be used. In one embodiment, when a subblock interleaver is used as the rate matching interleaver, a subblock interleaver sequence that considers at least one of binary domination, Hamming weight, or reliability of a polar code may be used. In one embodiment, when a subblock interleaver is used as the rate matching interleaver, a subblock interleaver of a subblock length determined based on the length of a parent code may be used.

[0352] The polar-coded BICM system uses a codeword vector before circular buffer rate-matching. Subblock unit interleaving is performed for . In this case, the number of subblocks is 32, and the number of codeword bits in each subblock is Is am.

[0353] The polar encoding BICM system uses a rate-matched codeword vector The input of the modulator is distributed to fading channels through pseudo-random interleaving. At this time, the characteristics of subblock interleaving (specifically, subblock interleaving that satisfies binary domination) are not utilized separately, and the codeword bits are randomly mixed.

[0354] The configuration included in this disclosure is summarized as follows.

[0355] Case 1: Applying a shortened polar code by applying a code sequence with a rate-matching interleaver (BICM system transmission block diagram configuration shown in Fig. 19)

[0356] According to one embodiment, the electronic device comprises a codeword vector prior to circular buffer rate-matching. Interleaving of sign sequences can be performed. In this case, the sign sequence is an index sequence sorted in ascending order of polar sign reliability. , and can satisfy binary domination. In one embodiment, the code sequence interleaving is bit-by-bit interleaving rather than sub-block-by-subblock interleaving.

[0357] In one embodiment, a codeword vector with a matched code rate before being fed into the input of the channel interleaver. can be grouped. In one embodiment, the grouping is a grouping that considers binary domination and diversity. At this time, The value of can be decided by

[0358] In one embodiment, individual interleaving can be performed for each of the above groups. Group 1 ( ) may not apply interleaving (identity interleaving), and group 2 ( ) can perform pseudo-random (e.g. triangular) interleaving.

[0359] In one embodiment, the above Adaptive addition-fixing rules can be introduced depending on the value.

[0360] Case 2: Applying subblock interleaver with rate-matching interleaver, applying shortened polar code (BICM system transmission block diagram configuration shown in Fig. 21)

[0361] According to one embodiment, the electronic device comprises a codeword vector prior to circular buffer rate-matching. Subblock unit interleaving can be performed for. In one embodiment, the subblock interleaver has a number of subblocks of 32, and the number of codeword bits in each subblock is It can have the following characteristics.

[0362] In one embodiment, a codeword vector with a matched code rate before being fed into the input of the channel interleaver. can be grouped as follows. In one embodiment, the above Is can be decided by

[0363] In one embodiment, the electronic device may perform individual interleaving for each group. In one embodiment, the group 1 ( ) and group 2 ( ) can perform pseudo-random (e.g. triangular) interleaving on each.

[0364] In one embodiment, a set of indices of bits to be extra-frozen for each code length (to ensure both sufficient diversity performance and AWGN performance) and a threshold of the number of message bits to be reused as data ( ) can be individually defined.

[0365] Case 3: Applying a subblock interleaver of a different type from the subblock used in Case 2 above as a rate-matching interleaver, applying a shortened polar code (configuration of the BICM system transmission block diagram shown in Fig. 23)

[0366] In one embodiment, the electronic device may generate a codeword vector prior to circular buffer rate-matching. In the above case 2, a different type of subblock unit interleaving than the subblock used can be performed. The subblock interleaver used in case 3 can have at least one of the following two characteristics.

[0367] 1) In one embodiment, the number of subblocks is 32 (same as the prior art), and the number of codeword bits in each subblock is also However, the sub-block interleaver sequence can be modified. For example, a binary domination sequence considering Hamming weights or a binary domination sequence similar to a sign sequence can be used, for example, [0 1 2 4 8 16 3 5 6 9 10 17 12 18 20 7 24 11 13 19 14 21 22 25 26 28 15 23 27 29 30 31] can be considered.

[0368] 1-2) In one embodiment, the number of subblocks can be defined differently for each code length. For example, a larger number of subblocks can be used for a longer code length. In the case of the subblock interleaver used in Case 2, The number of subblocks used and the number of bits within a subblock are 32 (N / 32), but other types of subblock interleavers can perform better grouping and interleaving by setting the number of subblocks to 128 and the number of bits within a subblock to 8.

[0369] 2) In one embodiment, a codeword vector with a matching code rate before being fed into the input of the channel interleaver. are grouped. At this time Is can be decided by

[0370] 3) In one embodiment, the electronic device can perform individual interleaving for each group. In one embodiment, group 1 ( ) and group 2 ( ) can perform pseudo-random (e.g. triangular) interleaving on each.

[0371] 4) In one embodiment, a set of indices of bits to be extra-frozen for each code length (to ensure both sufficient diversity performance and AWGN performance) and a threshold value of the number of message bits to be reused as data ( ) can be individually defined.

[0372] Case 4: Considering the sign sequence interleaver as a rate-matching interleaver, the subblock interleaver used in case 2, or the modified subblock interleaver used in case 3, and applying a punctured polar code (configuration of the BICM system transmission block diagram shown in Fig. 24).

[0373] In one embodiment, the electronic device may generate a codeword vector prior to circular buffer rate-matching. Rate-matching interleaving satisfying binary domination can be performed. In one embodiment, the rate-matching interleaver may be a code sequence interleaver, a sub-block interleaver, or a modified sub-block interleaver.

[0374] In one embodiment, a rate-matched (punctured) codeword vector before being fed into the input of the channel interleaver. are grouped. At this time Is can be decided by

[0375] In one embodiment, the electronic device performs individual interleaving for each group. Group 1 ( ) and group 2 ( ) can perform pseudo-random (e.g. triangular) interleaving on each.

[0376] In one embodiment, the 5G-NR additional fixation rule may be followed for the perforated polar code and no separate additional fixation may be added, but the scope of the present disclosure is not limited thereto.

[0377] FIG. 30 is a structural diagram illustrating the structure of an encoding device according to an embodiment of the present disclosure.

[0378] Referring to FIG. 30, the encoding device includes a processor (3001), a transceiver (3002), and a memory (3003). The structure illustrated in this drawing corresponds to one embodiment, and the encoding device may include additional units than those illustrated in FIG. 30.

[0379] The transceiver (3002) can transmit and receive signals with other electronic devices (e.g., receivers). The memory (3003) can store at least one of information related to the transceiver (3002) and information transmitted and received via the transceiver (3002). The memory (3003) can also store sequence information for polar coding to which the present invention is applied.

[0380] The processor (3001) can control the operation of the encoding device and can control the entire encoding device so as to perform operations related to the encoding device in each of the embodiments described above.

[0381] According to one embodiment of the present disclosure, the memory (3003) can store data such as basic programs, application programs, and setting information for the operation of the electronic device. In particular, the memory (3003) provides the stored data upon request of the processor (3001). The memory (3003) can be configured as a storage medium or a combination of storage media such as a ROM, a RAM, a hard disk, a CD-ROM, and a DVD. In addition, there can be a plurality of memories (3003). In addition, the processor (3001) can perform the above-described embodiments based on a program for performing the above-described embodiments of the present disclosure stored in the memory (3003), and can include at least one processor.

[0382] In the specific embodiments of the present invention described above, components included in the invention are expressed in the singular or plural form 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 invention is not limited to singular or plural components. Even components expressed in the plural form may be composed of singular elements, or even components expressed in the singular form may be composed of plural elements.

[0383] While the detailed description of the present invention has described specific embodiments, it is clear that various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be defined not only by the scope of the following claims but also by equivalents thereof.

Claims

1. A method for transmitting a polar code in a wireless communication system, A step of performing rate matching interleaving and rate matching on codeword bits corresponding to the polar code; A step of grouping the codeword bits on which the rate matching interleaving and rate matching are performed into a first bit group and a second bit group including different numbers of bits; A step of performing channel interleaving on at least one of the first bit group and the second bit group; and A method characterized by comprising the step of allocating and transmitting two bit groups on which the above channel interleaving has been performed to two or more fading channels.

2. In the first paragraph, the step of grouping the codeword bits for which the code rate matching interleaving and code rate matching are performed into a first bit group and a second bit group including different numbers of bits; A method characterized by comprising a step of grouping the codeword bits subjected to rate matching interleaving based on binary domination and rate matching according to the rate matching into the first bit group and the second bit group.

3. In paragraph 1, For the above code rate matching interleaving, a bit-by-bit interleaver based on a polar code sequence is used, A method characterized in that the above polar code sequence is expressed by sorting the indices of the separation channels based on reliability and satisfying binary domination.

4. A method according to claim 1, characterized in that some of the codeword bits are punctured or shortened for the purpose of matching the code rate.

5. In paragraph 4, Including a step of extra-freezing at least one source bit corresponding to the code bits on which the interleaving and code rate matching are performed, when an interleaver based on a sub-block is used for the rate matching interleaving, and some of the code bits are punctured for the rate matching; A method characterized in that the at least one additionally fixed source bit is determined based on at least one of the type of interleaver used for the rate-matching interleaving, the performance of the fading channels, or the performance of the AWGN channel.

6. In the first paragraph, when a sub-block interleaver is used for the code rate matching interleaving, the method is characterized in that the sub-block interleaver is related to a polar code sequence.

7. In the first paragraph, when a sub-block interleaver is used for the rate matching interleaving, the method is characterized in that the sub-block interleaver is based on a sub-block interleaver sequence that takes into account at least one of binary domination, Hamming weight, or reliability of polar code.

8. In the first paragraph, when a subblock interleaver is used for the code rate matching interleaving, a method characterized in that the length of a subblock of the subblock interleaver is determined based on the length of the parent code.

9. In an electronic device that transmits a polar code in a wireless communication system, Transmitter and receiver; and comprising at least one processor; At least one processor, Perform rate matching interleaving and rate matching on the codeword bits corresponding to the above polar code, The codeword bits for which the rate matching interleaving and rate matching have been performed are grouped into a first bit group and a second bit group containing different numbers of bits, Performing channel interleaving on at least one of the first bit group and the second bit group, and An electronic device characterized in that it is configured to allocate and transmit two bit groups on which the above channel interleaving has been performed to two or more fading channels.

10. In the 9th paragraph, the at least one processor, An electronic device characterized by comprising a step of grouping the codeword bits subjected to rate matching interleaving based on binary domination and rate matching according to the rate matching into the first bit group and the second bit group.

11. In paragraph 9, For the above code rate matching interleaving, a bit-by-bit interleaver based on a polar code sequence is used, An electronic device characterized in that the above polar code sequence is represented by sorting the indices of the separation channels based on reliability and satisfying binary domination.

12. An electronic device characterized in that, in the 9th paragraph, some of the code word bits are punctured or shortened for the purpose of matching the code rate.

13. In the 12th paragraph, the at least one processor, When a sub-block-based interleaver is used for the rate matching interleaving, and some of the codeword bits are punctured for the rate matching, at least one source bit corresponding to the codeword bits for which the interleaving and rate matching are performed is configured to be extra-frozen, An electronic device characterized in that the at least one additionally fixed source bit is determined based on at least one of the type of interleaver used for the rate matching interleaving, the performance of the fading channels, or the performance of the AWGN channel.

14. An electronic device according to claim 9, wherein, when a sub-block interleaver is used for the code rate matching interleaving, the sub-block interleaver is related to a polar code sequence.

15. In the 9th paragraph, when a sub-block interleaver is used for the rate matching interleaving, the sub-block interleaver is based on a sub-block interleaver sequence that considers at least one of binary domination, Hamming weight, or reliability of polar code, and An electronic device characterized in that, when a subblock interleaver is used for the above code rate matching interleaving, the length of a subblock of the subblock interleaver is determined based on the length of the parent code.

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