Apparatus and method for two-step encoding and decoding using polar code in communication system or broadcasting system

Abstract

The present disclosure relates to a system for efficiently transmitting data having a two-step structure on the basis of a polar code in a communication system or a broadcasting system such as 5G / 6G. A transmitter may determine an encoding mode of first information / second information, when the encoding mode is determined, encoding parameters of the first information and the second information may be determined, and the transmitter may perform polar encoding of the first information and polar encoding of the second information on the basis of the encoding parameters.

Description

Device and method for two-step encoding and decoding using polar codes in a communication system or broadcasting system

[0001] The present disclosure relates to a communication system or a broadcasting system, and more particularly, to a device and method for transmitting a signal using a polar code and data having a two-stage structure. Furthermore, the present disclosure relates to a device and method for decoding the transmitted signal.

[0002] Typically, when a transmitter and receiver transmit and receive data in a communication and broadcasting system, data errors may occur due to noise in the communication channel. To enable the receiver to process errors generated by the communication channel, there are two encoding methods: error detection codes and error correcting codes (ECC). Error detection codes allow the receiver to determine whether the received data contains errors, while error correcting codes allow the receiver to automatically correct errors in the received data. Error correction codes are also commonly referred to as channel coding or forward error correction (FEC).

[0003] There are various error-correcting coding techniques. Representative error-correcting codes include convolutional codes, turbo codes, low-density parity-check (LDPC) codes, and polar codes. In particular, turbo codes, low-density parity-check (LDPC) codes, and polar codes are excellent channel codes that achieve or approach theoretical channel capacity, and are utilized in various communication and broadcasting systems today.

[0004] References described in this disclosure are as follows:

[0005] [1] E. Arikan, “Channel Polarization: a method for constructing capacity-achieving codes for symmetric binary-input memoryless channels,” IEEE Trans. Information Theory, vol. 55, no. 7, pp. 3051-3073, July 2009.

[0006] [2] 3GPP, NR multiplexing and channel coding (Release 15), TSG RAN TS38.212 v15.0.1, Feb. 2017.

[0007] [3] A. Balatsoukas-Stimming, MB Parizi, and A. Burg, “LLR-based successive cancellation list decoding of polar codes,” IEEE Trans. Sig. Process., vol. 63, no. 19, pp. 5165 - 5179, June 2015.

[0008] Among the above error correction coding techniques, polar codes are channel codes that achieve point-to-point channel capacity in a simple and effective manner by exploiting a phenomenon called channel polarization [1]. When transmitting multiple bits through independent bit channels, encoding using a structured generator matrix and decoding using successive cancellation (SC) transforms the channel for each bit into a virtual polarized synthesized channel. During this process, some synthesized channels become good channels with a maximum channel capacity close to 1, while the remaining synthesized channels become poor channels with a minimum channel capacity close to 0. The sum of the channel capacities of the synthesized channels remains the same before and after the change. As the code length increases, channel polarization is maximized, so good channels have a channel capacity of 1, and poor channels have a channel capacity of 0. Therefore, the transmitter can theoretically easily and effectively achieve the channel capacity for a given channel by transmitting the information bits it wants to transmit on good channels and allocating frozen bits to bad channels.

[0009] The SC decoding method for the above polar codes can be easily modified and extended to near-maximum likelihood (or ML-like) decoding methods, such as SCL (SC-list) decoding, SCS (SC-stack) decoding, and SC-flip (SCF) decoding. These improved decoding algorithms achieve superior error correction performance. For this reason, the 3GPP NR, the 5G communication standard, uses polar codes when transmitting short-length control information [2].

[0010] This disclosure considers a communication and broadcasting system based on polar codes. In particular, it considers a case in which data with a two-stage structure can be transmitted in the communication and broadcasting system.

[0011] A two-level structure data is a method of transmitting variable-length data by dividing it into fixed-length first information and variable-length second information. In this transmission method, since the first information contains information for decoding the second information, there is a problem that if decoding of the first information fails, the second information cannot be decoded either. Therefore, in order to efficiently transmit two-level data, it is important to transmit the first and second information with appropriate robustness. If the robustness is too high, unnecessary parity information increases, reducing transmission efficiency. On the other hand, if the robustness is too low, the error rate increases, which can cause problems with service quality.

[0012] The present disclosure proposes a method and device for efficiently transmitting two-stage data using polar codes, supporting various lengths and code rates. Unlike LDPC or turbo codes, polar codes provide superior performance when rate matching methods are applied variably according to the code rate. Considering the characteristics of the rate matching method of polar codes, the present disclosure presents methods and embodiments for efficiently transmitting two-stage data.

[0013] According to embodiments of the present disclosure, a method performed by a device in a communication system or a broadcasting system may include an operation of transmitting or receiving a signal including bits encoded based on polar codes. The method divides data into a two-stage structure composed of first information and second information, and the first information includes information necessary for decoding the second information, including the length of the second information. An appropriate polar encoding method is applied to the first information, which is shorter than the second information, so that it can be transmitted more robustly than the second information, and polar encoding is applied to the second information, which is relatively longer than the first information and must support a wide variety of lengths and code rates, so that it can be transmitted flexibly, although less robustly than the first information.

[0014] In the present disclosure, the receiving operation may include first decrypting first information, obtaining parameters for decrypting second information based on the decrypted first information, and then decrypting the second information. Since the second information supports a wide variety of lengths and code rates, appropriate rate matching and rate dematching methods must be applied. The present disclosure includes a method for determining an appropriate rate matching / dematching method.

[0015] In embodiments of the present disclosure, a device performed by a device in a communication system or a broadcasting system may include a memory; at least one transmitter or receiver or transceiver; and at least one processor. The at least one processor may be configured to generate encoded bits based on polar codes and generate a signal to be transmitted to the receiver based on the generated encoded bits.

[0016] The at least one processor may be configured to receive a signal comprising bits encoded based on a polar code. The at least one processor may be configured to identify a polar code configuration for at least one information bit and at least one frozen bit of the signal. The at least one processor may be configured to perform decoding of the signal based on the configuration of the polar code.

[0017] A method performed by a transmitter in a communication system of the present disclosure, comprising: a step of identifying a first encoding mode for encoding first information bits and a second encoding mode for encoding second information bits; a step of identifying a first polar code sequence for encoding the first information based on the first encoding mode; a step of polar-encoding the first information based on the determined first polar code sequence to generate first polar-encoded bits; a step of selecting at least some of the first polar-encoded bits; a step of determining a length (E) of bits allocated for transmitting encoded second information bits based on a length (K) of the second information bits; a step of determining a rate matching method and a second polar code sequence to be applied to the second information bits based on the second encoding mode, the length (K) of the second information bits, and the length (E) of the allocated bits; a step of polar-encoding the second information bits based on the determined second polar code sequence to generate second polar-encoded bits;

[0018] A method comprising: performing rate matching on the generated second polar coded bits based on the determined rate matching method; generating modulation symbols based on at least some of the first polar coded bits and the second polar coded bits to which the rate matching is applied; generating a signal based on the generated modulation symbols; and transmitting the generated signal, wherein the first information bits have a fixed length, and the first information bits include information on a length (K) of the second information bits.

[0019] In addition, a method performed by a receiver in a communication system of the present disclosure comprises: receiving a signal corresponding to first information bits and second information bits; performing demodulation based on the received signal; identifying a first encoding mode applied by a transmitter to decode the first information bits and a second encoding mode applied by the transmitter to decode the second information bits based on the received signal; identifying a first polar code sequence for decoding the first information based on the first encoding mode; determining demodulated values ​​corresponding to punctured bits among first polar code bits generated based on the first information bits as 0; performing polar decoding based on the first polar code sequence and the demodulated values ​​corresponding to the first information bits and the demodulated values ​​corresponding to the punctured bits; determining a length (K) of second information bits based on the determined first information bits; The method is characterized by comprising: a step of determining a length (E) of bits allocated to transmit encoded second information bits in a transmitter based on the length (K) of the determined second information bits; a step of determining a rate matching method and a second polar code sequence applied to the second information bits in the transmitter based on the second encoding mode, the determined length (K) of the second information bits, and the length (E) of the allocated bits; and a step of performing polar decoding based on the determined second polar code sequence and demodulated values ​​corresponding to the second information bits.

[0020] In addition, in the transmitter of the communication system of the present disclosure, a transceiver; And a control unit connected to the transceiver, wherein the control unit checks a first encoding mode for encoding first information bits and a second encoding mode for encoding second information bits, checks a first polar code sequence for encoding the first information based on the first encoding mode, polar-encodes the first information based on the determined first polar code sequence to generate first polar-encoded bits, selects at least some of the first polar-encoded bits, determines a length (E) of bits allocated to transmit the encoded second information bits based on a length (K) of the second information bits, determines a rate matching method and a second polar code sequence to be applied to the second information bits based on the second encoding mode, the length (K) of the second information bits, and the length (E) of the allocated bits, polar-encodes the second information bits based on the determined second polar code sequence to generate second polar-encoded bits, and generates the second polar-encoded bits based on the generated second polar-encoded bits. The method comprises performing rate matching based on the determined rate matching method for bits, generating modulation symbols based on at least some of the first polar coded bits and the second polar coded bits to which the rate matching is applied, generating a signal based on the generated modulation symbols, and transmitting the generated signal, wherein the first information bits have a fixed length, and the first information bits include information about the length (K) of the second information bits.

[0021] In addition, in the communication system of the present disclosure, in the receiver, a transceiver; And a control unit connected to the transceiver, wherein the control unit receives a signal corresponding to first information bits and second information bits, performs demodulation based on the received signal, verifies a first encoding mode applied by the transmitter to decode the first information bits and a second encoding mode applied by the transmitter to decode the second information bits based on the received signal, verifies a first polar code sequence for decoding the first information based on the first encoding mode, determines demodulated values ​​corresponding to punctured bits among the first polar code bits generated based on the first information bits as 0, performs polar decoding based on the first polar code sequence and the demodulated values ​​corresponding to the first information bits and the demodulated values ​​corresponding to the punctured bits, determines a length (K) of second information bits based on the determined first information bits, and transmits the second information bits encoded in the transmitter based on the determined length (K) of the second information bits. The method is characterized by determining a length (E), determining a rate matching method and a second polar code sequence applied to the second information bits in the transmitter based on the second encoding mode, the length (K) of the determined second information bits, and the length (E) of the allocated bits, and performing polar decoding based on the determined second polar code sequence and demodulated values ​​corresponding to the second information bits.

[0022] The device and method according to embodiments of the present disclosure can improve data transmission efficiency by transmitting and receiving data having a two-stage structure based on a polar code.

[0023] The effects that can be obtained from the present disclosure are not limited to the effects mentioned above, and other effects that are not mentioned can be clearly understood by a person having ordinary skill in the art to which the present disclosure belongs from the description below.

[0024] FIG. 1 illustrates a communication system or broadcasting system according to embodiments of the present disclosure.

[0025] FIG. 2 illustrates an example of a configuration of a receiving device in a communication system or broadcasting system according to embodiments of the present disclosure.

[0026] FIG. 3 illustrates an example of transmitter operation in a polar encoding-based communication system or broadcasting system according to embodiments of the present disclosure.

[0027] FIG. 4 illustrates an example of receiver operation in a polar encoding-based communication system or broadcasting system according to embodiments of the present disclosure.

[0028] FIG. 5 illustrates an example of a sub-block interleaving operation in a polar code-based encoding or decoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0029] FIG. 6 illustrates an example of a rate matching method in a polar code-based encoding or decoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0030] FIG. 7 illustrates an example of a two-stage data structure of a communication system or broadcasting system according to embodiments of the present disclosure.

[0031] FIG. 8 illustrates an example of a decoding operation of a two-stage data structure of a communication system or broadcasting system according to embodiments of the present disclosure.

[0032] FIG. 9a illustrates an example of a polar code-based encoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0033] FIG. 9b illustrates an example of a method for encoding first information in a polar code-based encoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0034] FIG. 9c illustrates an example of a method for encoding second information in a polar code-based encoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0035] FIG. 10A illustrates an example of a polar code-based decoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0036] FIG. 10b illustrates an example of a method for decrypting first information in a polar code-based decryption process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0037] FIG. 10c illustrates an example of a method for decrypting second information in a polar code-based decryption process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0038] Hereinafter, embodiments of the present disclosure are described in detail with the attached drawings.

[0039] In describing the embodiments, descriptions of technical details that are well known in the technical field to which the present disclosure pertains and are not directly related to the present disclosure will be omitted. This is to ensure that the gist of the present disclosure is conveyed more clearly without obscuring it by omitting unnecessary explanations.

[0040] For the same reason, some components in the attached drawings are highlighted, omitted, or schematically depicted. Furthermore, the dimensions of each component do not entirely reflect its actual size. Identical or corresponding components in each drawing are assigned the same reference numbers.

[0041] 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. These embodiments are provided solely to complete the disclosure of the present disclosure and to fully inform those skilled in the art of the scope of the invention, and the present disclosure is defined solely by the scope of the claims. Like reference numerals may refer to like elements throughout the specification.

[0042] At this time, it will be understood that each block of the processing flowchart drawings and combinations of the flowchart drawings can be performed by computer program instructions. These computer program instructions can be installed in a processor of a general-purpose computer, a special-purpose computer, or other programmable data processing equipment, so that the instructions executed by the computer or the processor of the other programmable data processing equipment create a means for performing the functions described in the flowchart block(s). These computer program instructions can also be stored in a computer-available or computer-readable memory that can be directed to a computer or other programmable data processing equipment to implement the functions in a specific manner, so that the instructions stored in the computer-available or computer-readable memory can also produce a manufactured item that includes an instruction means for performing the functions described in the flowchart block(s). Since the computer program instructions may be installed on a computer or other programmable data processing device, a series of operational steps may be performed on the computer or other programmable data processing device to create a computer-executable process, and the instructions that cause the computer or other programmable data processing device to perform the steps for performing the functions described in the flowchart block(s) may also provide steps for performing the functions described in the flowchart block(s).

[0043] 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.

[0044] Here, the term '~ unit' used in this embodiment means a software or hardware component such as an FPGA or ASIC, and the '~ unit' performs certain roles. However, the '~ unit' is not limited to software or hardware. The '~ unit' may be configured to be on an addressable storage medium and may be configured to regenerate one or more processors. Thus, as an example, the '~ unit' includes components such as software components, object-oriented software components, class components, and task components, processes, functions, properties, procedures, subroutines, segments of program code, drivers, firmware, microcode, circuits, data, databases, data structures, tables, arrays, and variables. The functions provided within the components and '~ units' may be combined into a smaller number of components and '~ units' or further separated into additional components and '~ units'. In addition, the components and '~ units' may be implemented to regenerate one or more CPUs within a device or a secure multimedia card.

[0045] Hereinafter, various embodiments will be described in detail with reference to the attached drawings. At this time, it should be noted that the same components in the attached drawings are represented by the same reference numerals as much as possible. In addition, it should be noted that the drawings of the present disclosure attached below are provided to help understand the present disclosure, and the present disclosure is not limited to the forms or arrangements illustrated in the drawings of the present disclosure. In addition, detailed descriptions of well-known functions and configurations that may obscure the gist of the present disclosure will be omitted. It should be noted that in the following description, only the parts necessary for understanding the operation according to various embodiments of the present disclosure will be described, and the description of other parts will be omitted so as not to distract from the gist of the present disclosure.

[0046] In the following description, terms referring to signals (e.g., signal, information, message, signaling), terms referring to resources, terms for operational states (e.g., step, operation, procedure), terms referring to data (e.g., packet, user stream, information, bit, symbol, codeword), terms referring to channels, terms referring to network entities, terms referring to components of devices, etc. are examples for convenience of explanation. Therefore, the present disclosure is not limited to the terms described below, and other terms having equivalent technical meanings may be used.

[0047] In this disclosure, expressions such as "more than" and "less than" may be used to determine whether a specific condition is satisfied or fulfilled. However, this is merely a description to express an example and does not exclude descriptions such as "more than" or "less than." Conditions described as "more than" may be replaced with "more than," conditions described as "less than" may be replaced with "less than," and conditions described as "more than and less than" may be replaced with "more than and less than."

[0048] Although this disclosure describes some embodiments using terms used in some communication standards (e.g., 3rd Generation Partnership Project (3GPP)), these are merely examples for illustrative purposes. Various embodiments of this disclosure can be easily modified and applied to other communication systems.

[0049] FIG. 1 illustrates a communication system and a broadcasting system according to embodiments of the present disclosure.

[0050] Referring to FIG. 1, a transmitting device (110) and a receiving device (120) are illustrated as part of devices or nodes that utilize a wireless channel in a wireless communication system. FIG. 1 illustrates one transmitting device (110) and one receiving device (120), but a communication system or a broadcasting system may include multiple transmitting devices or multiple receiving devices. In addition, for convenience of explanation, in the present disclosure, the transmitting device (110) and the receiving device (120) are described as separate entities, but the functions of the transmitting device (110) and the receiving device (120) may be interchangeable. For example, in the case of an uplink in a cellular communication system, the transmitting device (110) may be a terminal, and the receiving device (120) may be a base station. In the case of a downlink, the transmitting device (110) may be a base station, and the receiving device (120) may be a terminal.

[0051] A base station is a network infrastructure that provides wireless access to terminals. Base stations have coverage defined based on the distance over which they can transmit signals. In addition to a base station, a base station may be referred to as a massive MIMO (multiple input multiple output) unit (MMU), an access point (AP), an eNodeB (eNB), a gNodeB (gNB), a 5th generation node, a 5G NodeB (NB), a wireless point, a transmission / reception point (TRP), an access unit, a distributed unit (DU), a transmission / reception point (TRP), a radio unit (RU), a remote radio head (RRH), or other terms having equivalent technical meanings. A base station may transmit a downlink signal or receive an uplink signal.

[0052] A terminal is a device used by a user that communicates with a base station via a wireless channel. In some cases, a terminal may be operated without the involvement of a user. That is, a terminal is a device that performs machine type communication (MTC) and may not be carried by a user. A terminal may be referred to as a 'user equipment (UE)', a 'mobile station', a 'subscriber station', a 'customer premises equipment (CPE)', a 'remote terminal', a 'wireless terminal', an 'electronic device', a 'vehicle terminal', a 'user device', or other terms having an equivalent technical meaning.

[0053] Although not illustrated in FIG. 1, in addition to communication between a base station and a terminal, a terminal may also perform direct communication (direction communication) with other terminals. For example, the terminal illustrated in FIG. 1 may support vehicular communication with other terminals. In the case of vehicular communication, in the LTE system, standardization work on V2X technology based on the device-to-device (D2D) communication structure was completed in 3GPP Release 14 and Release 15, and standardization work on NR V2X technology is in progress in 5G NR Release 16.

[0054] Depending on the link formed between communication nodes, the transmitting device and the receiving device may be defined in various ways. In one embodiment, the transmitting device (110) may be a base station, and the receiving device (120) may be a terminal. In addition, in another embodiment, the receiving device (120) may be a base station, and the transmitting device (110) may be a terminal. In another embodiment, both the transmitting device and the receiving device may be terminals. Hereinafter, the present disclosure describes the entity transmitting a signal as a transmitting device, and the entity receiving a signal as a receiving device, but this is only a functional expression for explaining the signal processing process, and is not to be construed as limiting a specific embodiment.

[0055] In embodiments, the transmitting device (110) may generate a codeword by encoding information bits based on polar codes, and the receiving device (120) may receive a signal corresponding to the codeword and decode the received signal based on the polar code. Subchannel allocation may be performed for input bits. Each input bit may be interpreted as passing through a subchannel (split channel, subchannel), which is a virtual channel of different quality, due to channel polarization. In this case, each subchannel is also referred to as a synthetic channel. After subchannel allocation, the transmitting device (110) may perform encoding based on the polar code using a generation matrix. The receiving device (120) may perform decoding based on the polar code through successive decoding (SC).

[0056] In embodiments, the transmitting device (110) may generate a codeword by encoding information bits based on an LDPC code. The receiving device (120) may receive a signal corresponding to the codeword and decode the received signal based on the LDPC code. For example, the receiving device (120) may use the LDPC decoding method according to the present disclosure and may perform a syndrome check to determine whether the decoding result is normal. The transmitting device (110) may perform LDPC encoding using a parity check matrix. The receiving device (120) may perform LDPC decoding using a parity check matrix. For example, the parity check matrix may include a parity check matrix defined in the 3GPP NR standard.

[0057] FIG. 2 illustrates an example of a configuration of a receiving device in a communication system or broadcasting system according to embodiments of the present disclosure. That is, the configuration illustrated in FIG. 2 can be understood as a configuration of a receiving device (120). Terms such as "... unit" and "... device" used hereinafter mean a unit that processes at least one function or operation, and this can be implemented by hardware, software, or a combination of hardware and software.

[0058] Referring to FIG. 2, the device may include a communication unit (210), a storage unit (220), and a control unit (230).

[0059] The communication unit (210) can perform functions for transmitting and receiving signals via a wireless channel. For example, the communication unit (210) can perform a conversion function between a baseband signal and a bit stream according to the physical layer specifications of the system. For example, when transmitting data, the communication unit (210) can generate complex symbols by encoding and modulating a transmission bit stream. In addition, when receiving data, the communication unit (210) can restore a reception bit stream by demodulating and decoding a baseband signal. In addition, the communication unit (210) can up-convert a baseband signal into an RF (radio frequency) band signal and transmit it through an antenna, and down-convert an RF band signal received through the antenna into a baseband signal.

[0060] To this end, the communication unit (210) may include a transmission filter, a reception filter, an amplifier, a mixer, an oscillator, a digital to analog convertor (DAC), an analog to digital convertor (ADC), etc. In addition, the communication unit (210) may include a plurality of transmission and reception paths. Furthermore, the communication unit (210) may include at least one antenna array composed of a plurality of antenna elements. In terms of hardware, the communication unit (210) may be composed of a digital unit and an analog unit, and the analog unit may be composed of a plurality of sub-units according to operating power, operating frequency, etc. In addition, the communication unit (210) may include a decoding unit to perform decoding according to various embodiments of the present disclosure.

[0061] The communication unit (210) transmits and receives signals as described above. Accordingly, the communication unit (210) may be referred to as a "transmitter," a "receiver," or a "transceiver." Furthermore, in the following description, transmission and reception performed via a wireless channel are used to mean that processing as described above is performed by the communication unit (210). Furthermore, if the device of FIG. 2 is a base station, the communication unit (210) may further include a backhaul communication unit for communication with other network entities connected via a backhaul network.

[0062] The storage unit (220) can store data such as basic programs, application programs, and setting information for the operation of the receiving device (120). The storage unit (220) can be composed of volatile memory, non-volatile memory, or a combination of volatile memory and non-volatile memory. In addition, the storage unit (220) can provide stored data upon request from the control unit (230).

[0063] The control unit (230) can control the overall operations of the device. For example, the control unit (230) can transmit and receive signals through the communication unit (210). In addition, the control unit (230) can record or read data from the storage unit (220). To this end, the control unit (230) may include at least one processor or microprocessor, or may be a part of a processor. According to various embodiments, the control unit (230) can control the device to perform operations according to various embodiments described below.

[0064] This disclosure covers some communication and broadcasting standards (e.g., 3 rd Although the embodiments are described using terms used in the Third Generation Partnership Project (3GPP), these are merely examples for explanation, and the various embodiments of the present disclosure can be easily modified and applied to other communication systems.

[0065] Polar codes are the first error correction codes that have been proven to achieve the channel capacity, which is the limit of data transmission performance in binary discrete memoryless channels (B-DMC), while having a low coding / complexity performance that can be implemented with error correction codes proposed by E. Arikan [1]. Polar codes and successive cancellation (SC)-based decoding methods enable superior error correction performance for short-length code transmission compared to other channel codes. Because of these advantages, polar codes are being used to transmit short-length control information in the 3GPP New Radio (NR), the 5th generation (5G) mobile communication standard.

[0066] The encoding method of the polar code may be defined in various ways depending on the system, but for convenience, the encoding method of the polar code performed according to TS 38.212, which is a 3GPP 5G NR standard, is described as an example.

[0067] Figures 3 and 4 are block diagrams conceptually representing polar encoding and decoding methods. Terms such as "...unit" and "...unit" used hereinafter refer to a unit that processes at least one function or operation, which may be implemented using hardware, software, or a combination of hardware and software.

[0068] FIG. 3 illustrates an example of a configuration of a transmitting device in a communication system or broadcasting system according to embodiments of the present disclosure.

[0069] Referring to FIG. 3, the transmitting device may include a segmentation unit (310), an external encoding unit (320), a polar encoding unit (330), a rate matching unit (340), and a channel interleaver unit (350). Meanwhile, the configuration of the transmitting device is only one embodiment of the present disclosure, and the scope of the present disclosure is not limited thereto. For example, the transmitting device may be composed of a communication unit, a control unit, and a storage unit (see the description of FIG. 2), and the control unit may include a segmentation unit (310), an external encoding unit (320), a polar encoding unit (330), a rate matching unit (340), and a channel interleaver unit (350), or the control unit may perform the functions of the segmentation unit (310), the external encoding unit (320), the polar encoding unit (330), the rate matching unit (340), and the channel interleaver unit (350), or the control unit may control the operations of the segmentation unit (310), the external encoding unit (320), the polar encoding unit (330), the rate matching unit (340), and the channel interleaver unit (350).

[0070] The segmentation unit (310) may perform an operation of dividing the data into two or more code blocks or data blocks when the size of the data to be transmitted is too large to be encoded into a single code block. Depending on the system, if there is no need to divide into multiple code blocks, the operation of the segmentation unit (310) may be omitted. The external encoding unit (320) may perform an operation of applying an external code to improve the decoding performance of the polar code before performing polar encoding. Polar codes without an external code provide good encoding performance only when the code length is very long, and are therefore not suitable for protecting data of a normal size. Therefore, external encoding may be performed based on a CRC (Cyclic Redundancy Check) code or a BCH (Bose, Chaudhuri, Hocquenghem) code. Data on which external encoding is completed undergoes polar encoding through the polar encoding unit (330). Once polar encoding is completed, the rate matching unit (340) can perform appropriate rate matching considering the resources allocated for transmission. Examples of rate matching methods include repetition, puncturing, and shortening. The rate matching unit (340) selects an appropriate rate matching method based on the total size of transmittable bits. If the size of transmittable bits and the polar code rate in the system are fixed, the process of selecting one of the multiple rate matching methods can be omitted, and one of repetition, puncturing, and shortening can be fixed. After the rate matching process is completed, the channel interleaver unit (350) can perform appropriate interleaving and then apply modulation to transmit the data. However, depending on the type of data, the operation of the channel interleaver unit (350) may be omitted.For example, in the case of transmission of downlink data, channel interleaving can be omitted, and in the case of transmission of uplink data, channel interleaving can be applied.

[0071] FIG. 4 illustrates an example of a configuration of a receiving device in a communication system or broadcasting system according to embodiments of the present disclosure.

[0072] Referring to FIG. 4, the receiving device may include a channel deinterleaver unit (410), a rate dematching unit (420), an external code support polar decoding unit (430), and a desegmentation unit (440) capable of receiving modulated data transmitted from a transmitting unit or transmitter. Meanwhile, the configuration of the receiving device is only one embodiment of the present disclosure, and the scope of the present disclosure is not limited thereto. For example, the receiving device may be composed of a communication unit, a control unit, and a storage unit as shown in FIG. 2, and the control unit may include a channel deinterleaver unit (410), a rate dematching unit (420), an external code support polar decoding unit (430), and a desegmentation unit (440), or the control unit may perform the functions of the channel deinterleaver unit (410), the rate dematching unit (420), the external code support polar decoding unit (430), and the desegmentation unit (440), or the control unit may control the operations of the channel deinterleaver unit (410), the rate dematching unit (420), the external code support polar decoding unit (430), and the desegmentation unit (440).

[0073] The channel deinterleaver unit (410) performs deinterleaving based on the values ​​obtained by demodulating the received signal corresponding to the transmitted modulated data. The values ​​obtained by performing the demodulation are defined as integers or rational values, and values ​​such as the log-likelihood ratio (LLR) are often used. If channel interleaving is not performed in the transmitting device, the operation of the channel deinterleaver unit may be omitted. If the channel interleaving method is not always applied depending on the system, the operation of the channel deinterleaver unit (410) may be omitted in the receiving device, and if the channel interleaving method is always applied, the channel deinterleaver unit (410) may always operate in the receiving device. In a system where channel interleaving or deinterleaving is applied variably, whether to apply it may be determined based on a pre-agreed criterion. The pre-agreed criterion may be determined through signaling information or may be determined based on the type of data. Here, the type of data may be classified as uplink data or downlink data.

[0074] The rate dematching unit (420) performs rate dematching on values ​​for which channel deinterleaving has been performed. Rate dematching refers to the process of processing bits generated based on polar codes in the transmitter that are not transmitted through shortening or puncturing as erasure, or of appropriately combining demodulated values ​​for bits that have been repeatedly transmitted. When shortening or puncturing is applied as a rate matching method, it is impossible to estimate whether the bits that have not been transmitted are 0 or 1, so the LLR values ​​of the corresponding bits are regarded as 0 (= erasure processing) and decoding can be performed. If bits that have been repeatedly transmitted through repetition are combined as a rate matching method, the LLR values ​​are added to combine them into one bit.

[0075] The polar decoding unit (430) supporting external code performs decoding based on the values ​​for which rate dematching has been completed. Unlike the transmitter where external code and polar code are performed separately, the receiver requires external code support when performing polar decoding. In the polar decoding process, multiple candidate bit-streams for successful decoding are defined, and the external code determines which of these multiple candidate bit-streams has a probability of successful decoding above a threshold. For example, even if multiple candidate bit-streams for successful decoding are determined in the polar decoding process, an accurate decoding result can be obtained by excluding cases in which an error is detected among the bit-streams based on the CRC code. The external code not only lowers the error rate in the decoding process of the polar code, but can also perform an error detection function. For example, if a CRC bit of X bits is appended as an external code, the receiver can use the CRC bit of a bit to determine a bit string that can be successfully decoded during the polar decoding process, and can use the CRC bit of (Xa) bits for the final restored bit string to detect errors. In general, in order to maximize decoding performance, the CRC bits should be appropriately separated and used for error correction and detection.

[0076] In this way, when polar decoding is performed based on external codes and error detection is completed, the desegmentation unit (440) can perform an operation of combining code blocks divided into two or more. In a system where code blocks are not divided into two or more, the operation of the desegmentation unit (440) may be omitted.

[0077] Below, some operations of the transmitter shown in the above-described Figure 3 will be described in detail. Since the operations of the receiver are symmetrical to those of the transmitter, a description of the self-evident operations of the receiver will be omitted.

[0078] A input bit strings to which Polar encoding is to be applied and (A > 0), and the code block segmentation related directives When the above indicator is The process of applying code block segmentation or attaching CRC bits to each code block can be expressed as follows.

[0079] [Code block segmentation and code block CRC appended]

[0080]

[0081] Segmentation indicator in the above [code block segmentation and code block CRC appending] process The value can be set based on various criteria. For example, in the case of a 5G system, whether or not to apply segmentation can be determined based on not only the length A of the input bit string but also the length E of the output bit string of rate matching to be performed after polar encoding. In addition, for uplink control information (UCI) which has a relatively large maximum length, whether or not to apply segmentation can be determined based on A and / or E, but for downlink control information (DCI) which has a relatively small maximum length compared to UCI, segmentation can always be not applied without determining whether or not to apply segmentation. In this way, whether or not to apply segmentation can be determined based on the number of input bits and / or the number of output bits and / or the type of data.

[0082] As an embodiment of the present disclosure, the above [code block segmentation and code block CRC appending] process is disclosed only for cases where there is one code block or the code block is divided into two through segmentation, but in general, the number of code blocks may be three or more. In a system that supports three or more code blocks through segmentation, the number of code blocks may be determined based on a specific reference value for a segmentation.

[0083] When the number of code blocks is C, if the number of input bits A is not a multiple of C, filler bits may be added to match the length of the code block. The number of filler bits is and A' can indicate the sum of the number of input bits and the number of filler bits. If A is not a multiple of C, is always positive, and if A is a multiple of C, Since it is 0, it means there is no filler bit.

[0084] The number of appended CRC bits L may be fixed or variable depending on the system or the purpose and / or length of the input bits. For example, in 5G, if the input bits are DCI (downlink control information), L is fixed to 24. If the input bits are UCI (uplink control information), L is set to 6 when the number of input bits is 12 to 19 or less, and L is set to 11 when the number of input bits is 20 or more. The number of CRC bits may be set differently depending on the system. For example, L may be determined as 7, 8, 9, ... when the number of input bits is 12 to 19 or less, and as 12, 13, 14, ... when the number of input bits is 20 or more.

[0085] Also a code block bit string In , r is an index indicating the rth code block, and if the same process is performed for each code block in various descriptions of the present disclosure, the index may be omitted for convenience.

[0086] For the current 5G standard, the maximum value of A (the number of input bits) is 1706, and since the maximum number of code blocks generated by segmentation is 2, each code block can consist of a maximum of 1706 / 2 = 853 bits when segmentation is applied. This maximum value of A may be set differently depending on the system. For example, if the number of code blocks generated by segmentation is at most m (m>2), the maximum value of A can be determined as 853m, which is a multiple of 853. (For example, when m=3, the maximum value of A is 2559, and when m=4, the maximum value of A is 3412.)

[0087] The maximum value of A can be determined not only by the number of code blocks but also by the number of CRC bits appended to the code blocks. For example, in the case of the current 5G system, since 11 CRC bits are appended to the code blocks in the uplink control channel, polar encoding is performed for a maximum of 864 (=853+11) bits. If the maximum number of bits for performing polar encoding is fixed at 864 bits but the number of CRC bits is increased from 11 bits to 12 bits or 13 bits, when the number of code blocks generated by segmentation is at most m, the maximum value of A can be defined as a multiple of (864-12) or (864-13) behavior. For example, if the number of CRC bits is 12 bits, the maximum value of A can be determined as 862*2=1704, 862*3=2586, 862*4=3448 depending on the maximum number of code blocks, and if the number of CRC bits is 13 bits, the maximum value of A can be determined as 861*2=1702, 861*3=2583, 861*4=3444 depending on the maximum number of code blocks.

[0088] The maximum value of A may be determined not only by the number of code blocks, but also by the number of CRC bits to be appended to the code block and / or the maximum length of the polar code. As a specific example, in the case of the current 5G system, the maximum length of the polar code is 1024, but if another communication or broadcasting system uses a polar code with a maximum length of 2048, the maximum number of bits to perform polar encoding can be considered as 1728 (= 864 * 2) bits. In addition, if the number of CRC bits is 11 bits, the maximum number of bits in one code block is 1717 (= 1728 - 11). In addition, if the maximum number of code blocks is 2, the maximum value of A can be determined as 3434 (= 1717 * 2). Similarly, if the number of CRC bits is 12 and 13 bits, respectively, the maximum number of bits that one code block can have is 1716 (= 1728 - 12) and 1715 (= 1728 - 13), respectively, and the maximum value of A can be determined as 3432 (= 1716*2) and 3430 (= 1715*2), respectively.

[0089] In general, if the maximum number of bits for performing polar encoding is N(p,max), the maximum number of code blocks is m, and the number of CRC bits appended to each code block is N(CRC), then the maximum value of A can be determined based on (N(p,max) - N(CRC))*m. In other words, the maximum value of A can be expressed as a value determined based on the maximum number of bits for performing polar encoding and / or the maximum number of code blocks and / or the number of CRC bits appended to each code block.

[0090] A code block bit string of length K determined through the above process The encoding bits are determined by performing polar encoding on Let . Here, the length N of the polar code is (n: positive integer) and is determined as follows based on the length E of the output bit string of rate matching to be performed after polar encoding.

[0091] [Determining the length of the polar code]

[0092]

[0093] In the above [Polar code length determination] process, the value N, which means the length of the polar code or the total number of encoded bits before rate matching is applied, can be determined based on the length E of the output bit string of rate matching corresponding to the amount of resources allocated to transmit the code block bits and the size K of the code block bits. In other words, N is determined based on a condition satisfied based on E and K. In addition, rate matching can be performed based on one of the methods such as repetition, puncturing, or shortening after polar encoding depending on the determined N value.

[0094] In 5G systems, the length of the bitstream after rate matching is determined before a specific rate matching method (repetition, puncturing, or shortening) is determined or the actual rate matching operation is performed. Of course, depending on the system, the specific rate matching method may be preset or determined regardless of the length of the output bitstream of the rate match. K / E is the effective code rate because it represents the ratio of the final output bitstream to the polar information word bits. Therefore, the process of determining the rate matching method of the polar code may also be determined based on the code rate R.

[0095] According to the above [determination of the length of the polar code], the value of E is greater than N. It can be seen that repetition is applied as a rate matching method when the actual code rate K / E is less than or equal to 9 / 16. Here, constant values ​​such as 9 / 8 and 9 / 16 are values ​​set appropriately for the polar code of the 5G system defined in 3GPP, and if the polar code of the system changes, this value can also be set to a different value.

[0096] In 5G system, n min = 5, so the minimum length of the polar code is 32. Also, in the uplink, n max = 10, n in downlink max = is set to 9, so the maximum length of the polar code is 1024 in the uplink and 512 in the downlink. Depending on the system or service, n min and / or n max The value of can be set differently.

[0097] In the 5G system, as an operation corresponding to the external encoding unit (320), in order to quickly perform error detection based on CRC bits in the case of downlink, a code block bit sequence with a length of K Interleaving is performed for the uplink, and interleaving is omitted for the uplink. In this way, interleaving of code blocks is not an essential operation in the encoding process of polar codes, but can be performed to achieve a specific purpose. In TS 38.212, a 5G standard specification document, the bit string after interleaving or skipping interleaving for the code block is Although expressed as such, in this disclosure, for convenience, it is independent of the application of interleaving. It is expressed as follows. That is, in the present disclosure, the bit string may mean that the result is skipped or that interleaving is applied.

[0098] The transmitter performs polar encoding based on a polar code sequence for a code block or a code block to which interleaving is applied. Generally, the polar code sequence considers the polarization characteristic of the polar code and indicates the order and position of the code block bits and the order and position of the constrained bits, such as frozen bits (or fixed bits) or parity bits. Polar codes have the characteristic that the decoding reliability of each bit to be recovered after decoding is polarized. Typically, frozen bits or parity bits are placed in bits with low decoding reliability, and code block bits are placed in bits with high decoding reliability. The optimization and configuration methods for these polar sequences may vary depending on the purpose of the system. For reference, the operation of indicating the order and position of each bit based on the polar code sequence and decoding reliability may also be expressed as split channel allocation or subchannel allocation.

[0099] The polar code sequence required for the polar encoding process can obtain the best encoding performance by using the optimized polar sequence for each length of the polar code, but in the 5G system, from a single polar code sequence , n = 5, 6, 7, 8, 9, 10, and a sequence of polar codes having lengths corresponding to 5, 6, 7, 8, 9, and 10 is determined and applied to polar encoding. In other words, a polar code sequence composed of subsets according to the required length is determined from a given polar code sequence, and then polar encoding is performed based on the polar code sequence.

[0100] While length-optimized polar encoding sequences can typically be designed independently, there are methods that can support polar codes of various lengths without significant performance degradation from a single polar encoding sequence designed using an appropriate greedy algorithm. A representative method is a method for performing polar encoding based on a nested sequence (hereinafter referred to as NSS, nested-structured sequence), as follows.

[0101] As a specific example of NSS, let us assume that there are polar code sequences of [Mathematical Formula 1].

[0102] < Mathematical Formula 1 >

[0103]

[0104]

[0105] In the above <Mathematical Formula 1>, the length is , the sequence i = 5, 6, 7, 8, 9 has the longest length In the sequence of cases We can see that it is identical to the subset of smaller numbers. For example, The sequence in this case is In the sequence of cases It is identical to the sequence obtained by selecting only smaller numbers. The important thing here is that the order of the selected numbers does not change.

[0106] In general, the length of a sequence satisfying the Nest structure is The sequence of numbers has length It can be obtained from a sequence of (j>i). For example, in the above <Mathematical Formula 1> The sequence in this case is Not only can it be obtained through the sequence of cases, It can be obtained in the same way through the sequence of cases.

[0107] NSS offers the advantage of superior storage efficiency because it can represent sequences of various lengths as a single sequence. However, it is difficult to avoid some performance degradation compared to optimized sequences for each length. Therefore, performance verification based on various computational experiments is necessary to identify sequences that minimize actual performance degradation.

[0108] Depending on the system, polar encoding can be performed based on a polar code sequence optimized for each length at the terminal or base station, but polar encoding can also be performed based on NSS, such as in the 5G system. Furthermore, once a polar code sequence suitable for the code length determined according to the system is determined, a wide variety of polar encoding methods can be applied to perform polar encoding. For example, polar encoding can be performed directly on the determined code block, but additional outer coding can be performed on the code block before polar encoding.

[0109] In the case of 5G systems, the number of information bits or input bits for transmitting DCI (downlink control information) from a terminal or base station go In this case (12- ) bits, a process of padding 0 is added. Therefore, polar encoding is performed for code blocks of at least 12 bits for DCI transmission. In addition, for UCI (uplink control information) transmission, the number of information word bits or input bits is increased. go In this case, a 3-bit parity bit is additionally generated by applying an appropriate external code based on the code block to which the CRC is appended, and then polar encoding is performed on the code block and the generated parity bit.

[0110] Polar encoding is typically performed based on a generator matrix capable of inducing polarization. This generator matrix can typically be defined recursively from a small matrix called a polarization kernel, using a method called Kronecker power. In some cases, it can also be defined as a matrix with additional bit-reversal permeation applied.

[0111] Polar coded bits are generated based on the polar coded sequence defined according to the system, by arranging input bits corresponding to information bits and restricted bits such as frozen bits (or fixed bits) or parity bits in an appropriate order, and then based on the above generation matrix. The generation matrix is ​​typically Because of the size, the length of the bit vector multiplied by the generating matrix and the length of the polar encoding bits are both is the same as . Typically, the generating matrix of a polar code is independent of the system. Although matrices of the same size are used, the polar sequences can be optimized and configured differently depending on the purpose of the system. Of course, if the generating matrix can also induce polarization, it can be tailored to the purpose of the system. It can also be defined as a form that is not a form.

[0112] In this disclosure, code block bits For convenience, the output bits after polar encoding is performed based on the above generation matrix Expressed as

[0113] After polar encoding is performed in the polar encoding unit (330), the rate matching unit (340) applies appropriate rate matching to select some or at least some of the encoded bits to suit the given resources and perform subsequent operations for transmission. A typical rate matching method is to select and apply one of repetition / puncturing / shortening, but depending on the system or service, some or all of the three methods may be applied as rate matching methods.

[0114] However, polar codes have a characteristic in which the decoding reliability varies greatly depending on the rate matching method. In the case of a system that applies rate matching to support various code rates and code lengths, the given polar code sequence may not be applied as is, but the polar code sequence may be modified to suit the rate matching method, such as repetition / puncturing / shortening, by considering the applied rate matching method. Since the polar encoding method in the 5G system also performs rate matching to transmit data of various lengths and code rates, the process of modifying the polar code sequence, which is the process of determining the order of the frozen bits (or fixed bits), parity bits, and input bits according to the determined rate matching method, is performed before applying the rate matching. In the case of the 5G polar code, since the polar code sequence has the NSS characteristic, the polar code sequence is determined to suit the required code length based on the polar code sequence defined in the standard, and then the polar code sequence is modified once again according to the rate matching method.

[0115] Since the polarized decoding reliability of bits to be restored after polar decoding varies significantly depending on the rate matching method, it may be difficult to support excellent performance by simply changing the polar code. In this case, the output bits after polar encoding are Additionally, sub-block interleaving may be performed. Sub-block interleaving is a separate operation from the bit interleaving of code block bits for the code block described above.

[0116] Input bits of sub-block interleaving in 5G systems Output bits for is defined as follows:

[0117] [Sub-block interleaving]

[0118]

[0119] The operation of the above [sub-block interleaving] can be simply expressed as in Fig. 5.

[0120] FIG. 5 illustrates an example of a sub-block interleaving operation in a polar code-based encoding or decoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0121] Fig. 5 illustrates a process of dividing the entire polar encoding bits into 32 sub-blocks and interleaving them in sub-block units. That is, in the operation of the above [sub-block interleaving], 32 means the number of sub-blocks, and P(i) means an interleaving pattern consisting of 32 sequences corresponding to the interleaving of the sub-blocks. In the case of a 5G system, one sub-block is divided into N / 32 bits, but this may be defined as a different value depending on the system. For example, when the number of sub-blocks is set to 16 or 64, the sub-blocks may be divided into N / 16 or N / 64 bits, respectively. The interleaving pattern P(i) may also be defined as a pattern consisting of 16 or 64 sequences depending on the number of sub-blocks.

[0122] Bits selected through rate matching for the output bits of sub-block interleaving When this is said, the above bits are determined based on the following process.

[0123] [Bit selection through rate matching]

[0124]

[0125] The repetition, puncturing, and shortening operations in the process of [bit selection through rate matching] are expressed in Figure 6.

[0126] FIG. 6 illustrates an example of a rate matching method in a polar code-based encoding or decoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0127] Referring to Figure 6, in case of repetition or shortening, the starting point of the transmitted bits is the 0th bit (the first bit), but in case of puncturing, the 0th bit is always excluded, and instead, the last (N-1)th bit can always be transmitted.

[0128] In [Polar code length determination] and [Bit selection through rate matching], the bit selection method can be determined according to the length E of the output bit string of rate matching corresponding to the amount of bit resources allocated to transmit code block bits and the length K of the code block bit string. Accordingly, in the case of a 5G system, parameters E and K can be determined to perform polar encoding.

[0129] The transmitting device finally selects the bits By applying modulation, an appropriate signal can be generated and transmitted to a receiving device. The transmitting device may, in some cases, apply additional channel interleaving after rate matching. In a 5G system, the transmitting device can transmit DCI without channel interleaving and apply channel interleaving to UCI.

[0130] Bits selected through rate matching in 5G systems The output bit sequence of the channel interleaver for When , channel interleaving is performed as follows.

[0131] [Channel Interleaving]

[0132]

[0133]

[0134] According to the above [channel interleaving] method, the parameter T that determines the size of channel interleaving can also be determined based on the length E of the output bit string of rate matching corresponding to the allocated resource amount.

[0135] In cases where the code rate of data of very different lengths must be supported, such as in a 5G system, the optimized encoding method varies depending on the length E of the final transmitted bit string, so the control unit (not shown) of the transmitting device (110) can appropriately control at least a part of the operation of the segmentation unit (310), the external encoding unit (320), the polar encoding unit (330), the rate matching unit (340), or the channel interleaver unit (350) of the transmitting device according to the value E. Similarly, the control unit (230) of the receiving device (120) can appropriately control at least a part of the operation of the channel deinterleaver unit (410), the rate dematching unit (420), the external code-supporting polar decoding unit (430), or the desegmentation unit (440) of the receiving device according to the value E.

[0136] Polar codes are generally applied to physical layer control channel or layer-1 signaling (hereinafter L1 signaling) data transmission because they exhibit excellent encoding performance for short-length data in physical channels.

[0137] Hereinafter, a method for transmitting control channel or L1 signaling data or relatively small data based on a polar code is described as an embodiment of the present disclosure.

[0138] First, in this disclosure, a method for efficiently applying a polar code in a data transmission structure having a two-stage structure as shown in FIG. 7 for transmitting signaling data or data is proposed.

[0139] FIG. 7 illustrates an example of a two-stage data structure of a communication system or broadcasting system according to embodiments of the present disclosure.

[0140] First, FIG. 7 illustrates a two-stage data structure (700), and considers a system that wishes to transmit first information (710) and second information (720). In the present disclosure, the first information (710) and the second information (720) may be changed in various ways to express data having a two-stage data structure. For example, the first information (710) may be expressed as first information bit(s), first signaling, first data, etc., and the second information (720) may be expressed as second information bit(s), second signaling, second data, etc. For example, when the first information and the second information are transmitted through a control channel or a preamble, etc., the first information and the second information may be L1 signaling information. For example, the first information may be mapped to L1-basic data, and the second information may be mapped to L1-detail data, etc. Alternatively, the first information and the second information may be general data transmitted through a data channel or a data PLP (physical layer pipeline). In this disclosure, we consider the operation of a system in which multiple data having the two-stage structure of FIG. 7 are transmitted through multiple slots or frames.

[0141] The characteristics of the above two-step data structure are described as follows. First, the first information may include information necessary for decoding the second information. In other words, the first information may include information about parameters necessary for the transmitter to encode and modulate the second information, or information about parameters necessary for the receiver to perform demodulation and decoding so that the second information can be obtained. For example, the first information may include part or all of the information corresponding to the length of the second information or information corresponding thereto, or the type of code for encoding the second information, the code rate, or the modulation order. Therefore, in order to obtain the second information, the first information must be obtained first. Here, the type of code may mean a parity check matrix in the case of an LDPC code, and may mean a polar code sequence and / or a code rate adjustment method such as shortening, puncturing, or repetition in the case of a polar code.

[0142] FIG. 8 illustrates an example of a decoding operation of a two-stage data structure of a communication system or broadcasting system according to embodiments of the present disclosure.

[0143] Referring to FIG. 8, the receiver can decode the first information (810).

[0144] And, the receiver can check parameters for decoding second information based on the decoded first information (820).

[0145] And, the receiver can decode the second information based on the determined parameters (830).

[0146] The first information may be encoded based on a length and code rate agreed upon between the transmitter and receiver, so that the receiver can decode the first information without separate information. In other words, the length of the first information may have a fixed value, or a fixed code rate may be applied to the first information. On the other hand, the second information may have a variable length or a variable code rate applied because its characteristics may be variably defined based on the first information.

[0147] In this case of having a two-stage data structure, if decoding of the first information fails, the second information cannot be decoded either, so the first information is encoded to have a robust characteristic compared to the second information. That is, the robustness of the first information can be encoded to be higher (or greater) than the robustness of the second information. To this end, the first information can be encoded to correspond to lower spectral efficiency compared to the second information. For example, a modulation method of a lower order can be applied to the first information than to the second information. Alternatively, when modulation of the same order is applied, the effective code rate corresponding to the first information can be lower than the effective code rate corresponding to the second information. In general, if the modulation order corresponding to the first information is Q1, the effective code rate is R1, and the modulation order corresponding to the second information is Q2, the effective code rate is R2, then Q1*R1 <Q2*R2를 만족해야 한다. 또한 제1 정보 및 제2 정보가 모바일 서비스를 지원하는 송수신 시스템에서 L1 시그널링 정보들에 대응되는 경우에는 매우 높은 신뢰성을 지원해야 하기 때문에 Q1, Q2는 2 또는 4의 값을 가질 수 있다.

[0148] The two-level data structure has the disadvantage of introducing delay because the first and second information must be sequentially decoded to receive all data. However, it has the advantage of increasing data transmission efficiency because the length of the second information can be variably adjusted to the required length. To maximize data transmission efficiency, the first information is limited to essential information and consists of tens to hundreds of bits (e.g., 200 bits). The second information can consist of hundreds to thousands of bits or more, depending on the system.

[0149] The present disclosure discloses a method for transmitting information bits having such a two-stage data structure based on a polar code.

[0150] In the above two-step data structure, if the first information and the second information are encoded based on polar codes, the first information corresponds to relatively short, fixed-length bits of less than several hundred bits. In addition, since the first information must be encoded more robustly than the second information, the modulation order as well as the code rate (or actual code rate) are relatively low. For example, if the first information or the second information is control channel information or L1 signaling information, QPSK (Quadrature Phase Shift Keying) or 16-QAM (Quadrature Amplitude Modulation) with a modulation order of 2 or 4 is applied, and the frequency efficiency may be set lower than the frequency efficiency applied to data transmission. Of course, since the first information must be transmitted more robustly than the second information, the frequency efficiency of the first information is always lower than that of the second information. Therefore, if the modulation order is the same, the code rate of the first information is lower than that of the second information. In particular, it is desirable that the code rate of the first information is always lower than 7 / 16, which is the reference value for determining the rate matching method. However, in cases where a modulation order of 6 or 8 is applied to transmit control information or signaling information, such as in a system targeting fixed TV services, the code rate may be higher than 7 / 16 depending on the information length. Here, the reference value 7 / 16 for the code rate is only used as the reference value for determining the rate matching method in the 5G system for convenience of explanation, and the reference value for the code rate may vary depending on the system. In addition, although the case where the first information or the second information is control channel information or L1 signaling information has been described above, the scope of the present disclosure is not limited thereto.That is, even if the first information or the second information is not control channel information or L1 signaling information, the modulation order may be 2 or 4, respectively, and the code rate may be lower than 7 / 16, and other modulation orders and other code rate reference values ​​may be used.

[0151] In this case, when the code rate (or actual code rate) is relatively low, repetition or puncturing is suitable as a rate matching method for adjusting the code rate during the polar encoding process, and shortening is not suitable. In this case, the case where the code rate is relatively low may mean, for example, a code rate lower than the code rate or reference value that can be applied to the first information in the two-stage data structure. In addition, since the length of the first information in the two-stage data structure is fixed, if the code rate or the allocated bit unit resource amount is determined in advance, one of the pre-determined methods among puncturing or repetition can be applied as the rate matching method to be applied for encoding the first information. In other words, unlike the 5G system, a pre-determined rate matching method can be applied to the first information without a process of determining the rate matching method according to the length of the information bit or the resource amount.

[0152] In a two-step data structure, if the encoding method of the first information is fixed to a single one, the information length, allocated resource amount, rate matching method, modulation method, etc. are all determined as one, so encoding can be performed without a separate indicator. Furthermore, if the length of the first information and the size of the allocated resource amount vary greatly, the rate matching method can be determined based on the length of the first information and the size of the allocated bit-unit resource amount, similar to the 5G system.

[0153] However, in cases where the length of the first information or the size of the allocated resource amount is very limited, a method of encoding the first information can be applied by defining multiple modes and introducing an indicator to indicate one of the modes. As a specific encoding method of the first information, a method of encoding the first information by defining multiple modes as shown in the following [Encoding Mode of the First Information] is proposed. Meanwhile, in the present disclosure, the encoding mode is defined for the convenience of explanation, but the term encoding mode is not necessarily used. That is, since the encoding mode is a term indicating a parameter or a set of parameters required for encoding, it can be replaced with another corresponding term. In addition, in the present disclosure, an indicator indicating an encoding mode can be expressed as an indicator indicating parameters required for encoding. In addition, the encoding mode of the present disclosure can be expressed as a decoding mode (on the receiver side), and the parameters required for encoding can also be expressed as parameters required for decoding.

[0154] [Encoding mode of the first information]

[0155] Mode-1: QPSK, K1, E1, perforation, FEC_type1

[0156] Mode-2: QPSK, K2, E2, perforation, FEC_type1

[0157] Mode-3: 16QAM, K3, E3, perforation, FEC_type1

[0158] Mode-4: 64QAM, K4, E4, repetition, FEC_type2

[0159] The reason why various modes can be defined for encoding and decoding the first information or the second information, such as the above [encoding mode of the first information], is that the target operating SNR (signal-to-noise ratio) of the system can be defined in multiple ways depending on the system situation. That is, the operating SNR of the system can be required in various ways depending on the scenario of the service supported. Therefore, multiple modes can be defined in order to set parameters for each encoding and decoding in order to operate most efficiently at each operating SNR. In addition, the first information or the second information can be variably encoded based on two or more different polar code sequences depending on the mode or encoding parameter. In this way, the first information and the second information can be protected by encoding and decoding the first information or the second information by selecting an appropriate mode according to the operating SNR of the system.

[0160] Referring to the above [encoding mode of the first information], each mode can define (or indicate) parameters for encoding the first information. The parameters for encoding the first information are determined in advance, and indicators indicating each mode are required. For example, since the above [encoding mode of the first information] is defined as a total of four modes, an indicator of at least 2 bits or more is required. However, the above encoding mode is only an example of the present disclosure and may be defined in various ways. The number of the encoding modes may change (for example, more than 2 or 4), and the length (number of bits) of the indicator may change depending on the number of encoding modes. In addition, the information included in the above [encoding mode of the first information] is described as including the size (or length, K) of the first information, a modulation order, a code type (FEC_type), a rate matching method (puncturing or repetition), and an allocated resource amount (E), but some of the above parameters may not be included, and parameters other than the above-described parameters may be included.

[0161] For example, although the sizes of the first information (K1, K2, K3, K4) may be different for each mode, they may all be defined identically (i.e., K1=K2=K3=K4). If the lengths of the first information are all the same and there is only one case, the encoding mode may not separately indicate a parameter for the length of the first information. In addition, if the rate matching method is applied to all modes in only one method of puncturing or repetition, the encoding mode may not separately indicate a parameter for the rate matching method. In other words, the mode indicator may only indicate parameters that are variable depending on each mode in addition to parameters that do not change regardless of the mode.

[0162] Similarly, if encoding or decoding is performed based on the same polar code sequence for each mode, each mode can be defined regardless of the type of the code. If encoding and decoding are performed by selecting one of two or more polar code sequences according to the mode, each mode can include (or indicate) a parameter corresponding to the characteristics of the polar code used. In the above [encoding mode of the first information], the distinction of the applied code is expressed as parameters FEC_type1, FEC_type2, but this is only an example and can be expressed in various ways. For example, the total code length, which is a representative characteristic of the polar code or ( ) can be distinguished by sign type.

[0163] If the polar code used for encoding or decoding has the NSS characteristic described above, a process of converting the polar sequence by considering the NSS characteristic based on a parameter corresponding to the type of the code may be added, even if there is only one polar sequence stored in the system. (For example, before performing polar encoding or decoding, a process of selecting only numbers smaller than N based on the length N of the code corresponding to the code type from a given polar sequence is performed.)

[0164] An indicator for determining (indicating) the mode defined in the above [encoding mode of the first information] can be confirmed before the step (810) of decoding the first information of FIG. 8. For example, the encoding mode can be determined based on another preamble signal (e.g., a bootstrap signal). Alternatively, the transmitter can transmit information indicating the encoding mode to the receiver via RRC signaling or L1 signaling (e.g., DCI, MAC CE). For a specific example, the transmitter can set a set of multiple parameters for encoding (or multiple encoding modes) via RRC signaling, and can transmit an indicator indicating one of the sets of parameters (the encoding mode) to the receiver via L1 signaling.

[0165] Alternatively, the transmitter may configure the receiver with a set of parameters to be applied for encoding (one encoding mode) via RRC signaling. Alternatively, the transmitter may configure the receiver with a set of parameters for encoding (one encoding mode) via L1 signaling. Alternatively, if the encoding method of the first information is predetermined, separate signaling may not be required. That is, if the encoding method of the first information is predetermined as described above, the transmitter may transmit information about one encoding method via RRC or L1 signaling or use a predetermined method.

[0166] Alternatively, a set of multiple parameters for encoding may be predefined, and the transmitter may transmit an indicator to the receiver via RRC signaling or L1 signaling.

[0167] Alternatively, the receiver may perform demodulation based on the received signal and then obtain an indicator value based on the demodulated value, or determine an indicator value based on a correlation characteristic of the received signal.

[0168] Depending on the determined mode, the receiver can determine parameters required for decoding the first information and perform decoding of the first information based on the parameters.

[0169] Since the first information includes parameters for encoding and decoding the second information, if the first information is successfully decoded, the parameters for encoding and decoding the second information can also be determined. Unlike the first information, the second information can support a wide range of lengths, from several hundred bits to several thousand bits or more, and a wide range of encoding rates, and thus may require a wider range of parameters.

[0170] The basic parameters required for encoding and decoding the second information may include a modulation order Q, the length K of the second information, and the amount of allocated resources E or values ​​corresponding to E. However, since the length K of the second information is highly variable, the amount E of the allocated resources is also highly variable, so it is very inefficient to include both K and E values ​​in the first information. If a rule is applied in which the value of E is determined according to the value of K, the value of E can be inferred even if the first information only includes K, thereby improving the overall transmission efficiency.

[0171] For example, if the code rate R that can be set in the first information is limited and the code rate is included as a parameter in the first information, the value of E can be determined using the relationship E = K / R. Here, limiting the code rate R means using one of several code rates that have been determined in advance, and each code rate can be expressed through an indicator (or bit information). For example, if the code rates R are limited to 16, such as R1, R2, R3, ..., R16, each code rate can be expressed in order as 0000, 0001, 0010, 0011, ..., 1111, and 4 bits of indicator (or bit information) are required.

[0172] A more efficient way to do this is to determine the value of E based on a rule defined in advance for the value of K, such as f(K)=E. In this case, f(x) can mean an integer function defined based on the integer x. f(K) can be defined in various forms, but is usually expressed based on a linear equation form, such as f(K)=aK+b. However, since the coefficient a does not necessarily have to be an integer, or or You can use the following relationship: is the largest integer less than or equal to x, is the smallest integer greater than or equal to x, and Round(x) means the integer rounded to the nearest integer for x.) In general, or or An appropriate correction value c may be included, such as f(K) = E. When f(K) = E, it means that Nf(K) bits are punctured during the polar encoding process, or f(K) - N bits are repeated. (N: length of the polar code)

[0173] The value of f(K) can also mean the number of bits to be punctured, such as f(K) = NE. In other words, rather than directly determining the allocated bit unit resource amount E based on the value of K, the value of E is determined by determining the number of bits to be punctured. can be determined as follows. If f(K) means the number of bits to be punctured, f(K) can be defined to mean that puncturing is applied when f(K)>0, and repetition is applied as many as f(K) bits when f(K)<0. Or, of course, a rule g(K) that determines the number of repetition bits by considering repetition can be defined separately. For reference, all rules defined in the above dictionary must be determined so that the value E is necessarily a multiple of Q. In addition, the K value can be defined based on the number of bits including the parity bit of an external code such as a CRC or BCH code, or can be defined as the number of information bits excluding the number of parity bits of an external code.

[0174] Unlike the first information, the second information can support a wide range of lengths and code rates, so it may not be easy to support good performance with only puncturing and repetition like the first information. Therefore, if the E value is defined based on the K value, the polar sequence can be determined based on the K and E values, and the most appropriate method among shortening, puncturing, and repetition can be selected to support the desired code rate. If the K value is very limited, the rate matching method can also be defined according to multiple modes similar to the first information. However, since the K value is basically not limited, it is inefficient to determine all the parameters required for encoding and decoding for each mode in advance. Therefore, the encoding mode for the second information can typically be defined according to all or at least part of the modulation order and the constant values ​​a, b, and c of the rule f(K).

[0175] As a concrete example, examples of multiple modes defined for encoding and decoding of second information are given below.

[0176] [Second Information Encoding Mode]

[0177] Mode-1: QPSK, FEC_type1, ,

[0178] Mode-2: 16-QAM, FEC_type1, ,

[0179] Mode-3: 64-QAM, FEC_type1, ,

[0180] Mode-4: 256-QAM, FEC_type2, ,

[0181] The indicators indicating the four modes defined in the above [encoding mode of the second information] may be included in the first information, and the same indicator as the indicator for indicating the [encoding mode of the first information] described above may be used. For example, among the indicators consisting of two or more bits, if the two-bit value is 00, it means encoding mode 1 of the first information and encoding mode 1 of the second information, if it is 01, it means encoding mode 2 of the first information and encoding mode 2 of the second information, if it is 10, it means encoding mode 3 of the first information and encoding mode 3 of the second information, and if it is 11, it means encoding mode 4 of the first information and encoding mode 4 of the second information. That is, the encoding modes of the first information and the second information may be indicated simultaneously through one indicator.

[0182] The first information and the second information may be encoded and decoded based on the same polar code, or may be encoded and decoded based on different polar codes. The first information and the second information may be variably encoded based on two or more polar code sequences according to a pre-determined mode. Since the mode is determined in advance by considering all or part of the length of the information, the modulation order, or the amount of allocated resources, a polar sequence suitable for obtaining optimized encoding and decoding performance may also be determined in advance. In this case, as mentioned above, a parameter capable of distinguishing the corresponding polar code sequence (or type of code) may be included in the parameters for encoding or decoding.

[0183] Typically, for the convenience of implementation, only one polar code sequence having NSS characteristics is stored in the transmitter or receiver belonging to the system, and encoding and decoding can be performed by appropriately converting the sequence based on the length of the polar code required according to the first information, the second information, and each mode.

[0184] Although the present disclosure describes a case where at least some of the parameters for encoding and decoding the first information and the second information are variable, a system in which the parameters are fixed may also be considered. If all or some of the parameters for encoding and decoding are the same for all modes, there is no need to define the parameters according to the mode. In particular, if all parameters are the same regardless of the mode, the above indicator or mode distinction may not be necessary. However, considering the flexibility of the system, the present disclosure describes a case in which at least some of the encoding and decoding parameters for the second information are variable.

[0185] The operation of a system that transmits and receives data in a two-step structure based on polar codes is briefly summarized as follows.

[0186] [Transmission operation of the 2-step data structure]

[0187] Step 1) The transmitter can determine the encoding mode of the first information and / or the second information, and set the value of the indicator corresponding to the mode. When the encoding mode of the first information and the encoding mode of the second information have a 1:1 correspondence relationship or are defined as the same single mode, the encoding modes of the first information and the second information can be set as a single indicator. When the encoding mode of the first information and the encoding mode of the second information are different, the encoding modes of the first information and the second information can be set as separate indicators, or information on the encoding mode of the second information can be included in the first information.

[0188] Step 2) The transmitter encodes the first information based on the above encoding mode (first encoding mode).

[0189] - Determine parameters for encoding the first information corresponding to the above encoding mode. The parameters may include at least one of a modulation order, a code type (FEC_type), and a rate matching method (puncturing or repetition).

[0190] - If the polar code used is the same for all cases, the code type does not need to be defined according to the mode. That is, the parameter corresponding to the encoding mode indicated by the indicator may not include the code type. Similarly, if the rate matching method is the same for all modes, the rate matching method does not need to be defined according to the mode. That is, the parameter corresponding to the encoding mode indicated by the indicator may not include the rate matching method.

[0191] - Encoding of the first information is performed based on parameters for encoding the first information.

[0192] - Here, the first information includes at least a length K value of the second information among the parameters for encoding the second information.

[0193] Step 3) The transmitter encodes the second information based on the encoding mode (second encoding mode) for the second information. As described above, the encoding mode for the second information may have a 1:1 correspondence with or be identical to the encoding mode for the first information. Accordingly, the transmitter may encode the second information based on the encoding mode indicated by the indicator. Alternatively, if the encoding mode for the second information is separately set via a separate indicator, the transmitter may encode the second information based on the set encoding mode. Alternatively, if information on the encoding mode for the second information is included in the first information, the transmitter may encode the second information based on the encoding mode for the second information included in the first information.

[0194] - The transmitter determines parameters for encoding the second information corresponding to the encoding mode. The set parameters may include at least one of constant values ​​applied to the rules for determining a modulation order, a code type (FEC_type), and a value corresponding to the E value.

[0195] - The transmitter determines the E value based on the parameters for encoding the second information and the length K of the second information. Here, the E value is a multiple of the modulation order.

[0196] - The transmitter determines one of puncturing, shortening, or repetition as an appropriate rate matching method based on the determined E value.

[0197] - The transmitter determines the polar encoding sequence according to the determined rate matching method.

[0198] - The transmitter encodes the second information based on the determined parameters, polar encoding sequence, and rate matching method.

[0199] Step 4) Modulate the encoded first information and second information and transmit a signal to the receiver.

[0200] - The transmitter generates a modulation symbol based on a modulation order set for modulating the first information and the second information corresponding to the above-set encoding mode.

[0201] - The transmitter generates a signal based on the modulation symbol and transmits it to the receiver.

[0202] In cases where the transmission characteristics of a broadcasting network do not significantly vary, such as in fixed-line TV broadcasting systems, the encoding mode can be maintained for a long period of time without change, based on national and regional characteristics. In other words, in the [Transmission Operation of the Two-Step Data Structure] above, the step of determining the encoding mode is not performed every time for services where the network characteristics do not significantly change, but may be omitted once set.

[0203] Referring to the above [Transmission operation of the 2-step data structure], the polar encoding process of the second information is examined. First, the length K of the information is determined, then the resource allocation amount in bit units or the value E indicating the total number of transmission bits is determined, and from this, a rate matching method is determined, and then a polar code sequence suitable for the rate matching method can be determined. Encoding can be performed based on the polar code sequence and rate matching method determined in this way, and then modulation and transmission can be performed.

[0204] [Receive operation of 2-step data structure]

[0205] Step 1) The receiver determines the value of an indicator indicating the encoding mode of the first information and / or the second information based on the received signal. At this time, demodulation may be performed based on the received signal and the value of the indicator may be obtained based on the demodulated value. However, the value of the indicator may also be determined without demodulation based on the correlation characteristics of the received signal. Alternatively, the receiver may receive the value of the indicator based on the above-described method and determine the encoding mode based on this.

[0206] Step 2) The receiver performs demodulation based on the received signals corresponding to the encoded first information and second information, and determines the demodulated values. Typically, the LLR value is used.

[0207] - This action can also be performed together with Step 1).

[0208] Step 3) The receiver decodes the first information based on the encoding mode (first encoding mode) and the demodulated values ​​corresponding to the first information.

[0209] - Determine parameters for decoding the first information corresponding to the above encoding mode. The parameters may include at least one of a modulation order, a code type (FEC_type), and a rate matching method (puncturing or repetition).

[0210] - If the polar code used is the same for all cases, the code type does not need to be defined according to the mode. That is, the parameter corresponding to the encoding mode indicated by the indicator may not include the code type. Similarly, if the rate matching method is the same for all modes, the rate matching method does not need to be defined according to the mode. That is, the parameter corresponding to the encoding mode indicated by the indicator may not include the rate matching method.

[0211] - Decryption of the first information is performed based on the parameters for decryption of the first information.

[0212] - Here, the first information includes at least a length K value of the second information among the parameters for decrypting the second information.

[0213] Step 4) The receiver decodes the second information based on the encoding mode (second encoding mode) for the second information and the demodulated values ​​corresponding to the second information. As described above, the encoding mode for the second information may have a 1:1 correspondence with or be identical to the encoding mode for the first information. Therefore, the receiver can decode the second information based on the encoding mode indicated by the indicator. Alternatively, if the encoding mode for the second information is separately set via a separate indicator, the receiver can decode the second information based on the set encoding mode. Alternatively, if information on the encoding mode for the second information is included in the first information, the receiver can check the encoding mode for the second information included in the first information and decode the second information based on the encoding mode for the second information.

[0214] - The receiver determines parameters for decoding the second information corresponding to the encoding mode. The set parameters may include at least one of constant values ​​applied to the rules for determining a modulation order, a code type (FEC_type), and a value corresponding to the E value.

[0215] - The receiver determines the E value based on the K value determined from the first information and the parameters for decoding the second information. Here, the E value is a multiple of the modulation order.

[0216] - The receiver determines one of puncturing, shortening, or repetition as an appropriate rate matching method based on the determined E value.

[0217] - The receiver determines the polar encoding sequence according to the determined rate matching method.

[0218] - The receiver sorts the demodulated values ​​based on the above-determined polar encoding sequence and rate matching method. For punctured bits, a process of processing them as loss may be additionally performed; for shortened bits, a process corresponding to the case where the probability of the corresponding bits being 0 is 1; and for repeated bits, a process of appropriately combining the demodulated values ​​may be additionally performed.

[0219] - The receiver decodes the second information based on the determined parameters, polar encoding sequence, rate matching method, and demodulated values.

[0220] Looking at the polar decoding process of the second information with reference to the above [reception operation of the 2-step data structure], even if the receiver knows the length K value of the second information from the decoding of the first information, it cannot know the exact rate matching method or polar code sequence until the E value meaning the resource allocation amount in bit units or the total number of transmission bits is determined. Therefore, the receiver can determine E based on K, and then determine the polar code sequence and rate matching method based on E, and then properly sort the demodulated values. After the demodulated values ​​are properly sorted, if puncturing is applied, the punctured bits are set to a value corresponding to the case where the probability of the corresponding bit being 0 / 1 is equal (i.e., 1 / 2 each) (e.g., LLR = 0), and if shortening is applied, the corresponding bits are set to a value corresponding to the case where the probability of the corresponding bit being 0 is 1 (i.e., 100%) (e.g., LLR = LLR_max (maximum value of LLR set in the system)), and then polar decoding can be performed. When repetition is used as a rate matching method, the demodulated values ​​of the repeatedly transmitted bits are appropriately combined. If the demodulated values ​​are LLR-based, the combination means the sum of the LLRs.

[0221] For reference, although the detailed encoding and decoding process was not described in the above [Transmission operation of the 2-step data structure] and [Reception operation of the 2-step data structure], in the overall encoding and decoding process of the present disclosure, as described above, all or part of the sub-block interleaving, bit selection process, channel interleaving process, etc. may be additionally performed. In addition, determining the polar code sequence does not mean simply listing the sequence, but means that freezing bits, CRC or parity bits, information bits, etc. can be allocated based on the polar code sequence.

[0222] An embodiment of the transmission and reception operations of a specific two-step data structure is described with reference to FIGS. 9a, 9b, 9c and 10a, 10b, 10c.

[0223] FIG. 9a illustrates an example of a polar code-based encoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0224] Referring to FIG. 9A, the transmitter can first determine the encoding mode of the first information / second information (910). Here, the encoding modes of the first information / second information may be individually set via different indicators, or may be set simultaneously via a single indicator. Alternatively, information regarding the encoding mode of the second information may be included in the first information. Since the specific details are the same as described above, they are omitted below.

[0225] Once the encoding mode is determined, encoding parameters of the first information and the second information can be determined (920).

[0226] Accordingly, the transmitter can perform polar encoding (930) of the first information and polar encoding (940) of the second information based on the encoding parameters. The encoding parameters of the first information and the encoding parameters of the second information do not affect each other. In addition, since the first information and the second information are typically determined in advance, the transmitter can perform polar encoding (930) of the first information and polar encoding (940) of the second information simultaneously.

[0227] A specific example of the polar encoding (930) process of the above first information is shown in Fig. 9b.

[0228] FIG. 9b illustrates an example of a method for encoding first information in a polar code-based encoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0229] First, for polar encoding of the first information, parameters for the information length K, the final number of transmission bits E, and the length N of the polar code can be confirmed (931). Here, the length N of the polar code can be a parameter corresponding to the code type (FEC type). In particular, in the case of a system using a polar code sequence in the form of NSS, there is only one stored polar code sequence, and since it is transformed and used according to the code length N, the code type can directly correspond to the length N.

[0230] The transmitter can determine a polar code sequence based on the N value (933). If a modification of the polar code sequence is required, the transmitter can apply the modification to determine the polar code sequence (933). At least one of the K or E values ​​can be further considered to determine the polar code sequence.

[0231] The transmitter can perform (N, K) polar encoding based on the above-determined polar code sequence (935).

[0232] And, the transmitter can perform puncturing for (N - E) bits to match the transmission resource amount E in bit units (or to match the code rate) after the (N, K) polar encoding is performed (937). However, although the present embodiment has been described with an example of puncturing, step 937 can be changed to a step of performing rate matching based on the determined rate matching method. If the determined rate matching method is puncturing, the transmitter can perform puncturing for (N - E) bits. However, if repetition is applied as the rate matching method, the transmitter may perform repetition for (E - N) bits in step 937.

[0233] A more specific example of the polar encoding (940) process of the above second information is shown in Fig. 9c.

[0234] FIG. 9c illustrates an example of a method for encoding second information in a polar code-based encoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0235] First, for polar encoding of the first information, parameters for the information length K and the final polar code length N can be confirmed (941). Here, the parameter for the polar code length N may be a value defined according to the encoding mode, but the value of K is unrelated to the encoding mode. The polar code length N may be a parameter corresponding to the code type (FEC type). In particular, in the case of a system using a polar code sequence in the form of NSS, there is only one stored polar code sequence, and since it is transformed and used according to the code length N, the code type can directly correspond to the length N.

[0236] The transmitter can determine the value E corresponding to the final number of transmission bits based on the value K (943). Here, the value E must be a multiple of the modulation order Q, and the rule for calculating the value E is predetermined, and the parameters or Q values ​​to be used in the rule can be predefined according to the encoding mode.

[0237] The transmitter can determine a rate matching method among puncturing, shortening, and repetition to support optimal polar encoding performance based on the K, N, and E values, and determine a polar code sequence accordingly (945). Here, if a transformation of the polar code sequence is required based on the N value, the transmitter can apply the transformation to determine the polar code sequence (945).

[0238] The transmitter performs (N, K) polar encoding based on the above-determined polar code sequence (947).

[0239] And, after the (N, K) polar code is performed, the transmitter performs rate matching (949) based on the rate matching method determined in step (945). The rate matching serves to determine the final transmission bits according to the transmission resource amount E value in bit units. If puncturing is determined by the rate matching method, the transmitter can perform puncturing for NE bits, and if repetition is determined by the rate matching method, the transmitter can perform repetition for EN bits.

[0240] FIG. 10A illustrates an example of a polar code-based decoding process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0241] Referring to FIG. 10A, first, the receiver can check the value of the indicator corresponding to the encoding mode of the first information / second information from the received signal, and can check the encoding mode of the first information / second information (1010). Since the encoding mode of the transmitter corresponds to the decoding mode of the receiver, it can also be called an encoding mode or a decoding mode in the receiver. As mentioned above, the decoding modes of the first information / second information can be set separately through different indicators, or can be set simultaneously through a single indicator. Alternatively, information on the decoding mode of the second information can be included in the first information. Since the specific details are the same as described above, they are omitted below.

[0242] Once the decryption mode is determined, decryption parameters of the first information and the second information can be determined (1020).

[0243] Accordingly, the receiver can perform polar decoding (1030) of the first information and polar decoding (1040)(1050) of the second information based on the decoding parameters.

[0244] A more specific example of the polar decoding (1030) process of the above first information is shown in Fig. 10b.

[0245] FIG. 10b illustrates an example of a method for decrypting first information in a polar code-based decryption process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0246] First, for polar decoding of the first information, parameters for the information length K, the number of final transmission bits E, and the length N of the polar code can be confirmed (1031).

[0247] The receiver can determine a polar code sequence based on the N value (1033). If a modification of the polar code sequence is required, the receiver can apply the modification to determine the polar code sequence (1033). At least one of the K or E values ​​may be further considered to determine the polar code sequence.

[0248] And, the receiver can perform a rate dematching operation (1035). When puncturing is applied as a rate matching method, since the received signal does not have a signal corresponding to the punctured (N - E) bits, the receiver performs a rate dematching operation. Here, the rate dematching operation means setting the LLR value corresponding to the punctured (N - E) bits to 0 after demodulation is completed (1035). Setting the value corresponding to the punctured NE bits to 0 may mean processing them as bits lost from the channel.

[0249] The receiver can perform polar decoding based on the demodulated values ​​and the values ​​set to LLR = 0 through rate dematching and the polar code sequence (1037). Specifically, the receiver decodes the second information by performing (N, K) polar decoding based on the decoder input values ​​(usually determined as integer values ​​or rational values) corresponding to a total of N bits consisting of the demodulated LLR values ​​of E bits and the values ​​set to LLR = 0 corresponding to the punctured bits of (N - E) bits and the determined polar code sequence (1037).

[0250] Although this embodiment has been described using an example in which puncturing is applied as a method of rate matching, a case in which repetition is applied as a method of rate matching can also be considered. If repetition is applied as a method of rate matching, since the demodulated values ​​of bits repeated as many as (E - N) bits exist in the received signal, the receiver can perform polar decoding based on the demodulated values ​​(or by appropriately combining the demodulated values). If the decoder input values ​​are in the form of LLR, the LLR values ​​of the repeated bits can be added together.

[0251] Unlike the transmission operation, the reception operation requires decoding of the first information to obtain information about the length K of the second information. Therefore, after the decoding (1030) of the first information is completed, the receiver must obtain additional information (1040) necessary for decoding the second information before performing the decoding (1050) of the second information. The additional information must include information about K.

[0252] A more specific example of the polar decoding (1050) process of the above second information is shown in Fig. 10c.

[0253] FIG. 10c illustrates an example of a method for decrypting second information in a polar code-based decryption process of a communication system or broadcasting system according to embodiments of the present disclosure.

[0254] First, for polar decoding of the first information, parameters for the information length K and the final polar code length N can be confirmed (1051). Here, the parameter for the polar code length N may be a value defined according to the decoding mode, but the value K is a value included in the first information regardless of the decoding mode. The polar code length N may be a parameter corresponding to the code type (FEC type). In particular, in the case of a system using a polar code sequence in the NSS form, there is only one stored polar code sequence, and since it is transformed and used according to the code length N, the code type can directly correspond to the length N.

[0255] The receiver can determine the value E corresponding to the final number of transmitted bits based on the value K (1053). Here, the value E must be a multiple of the modulation order Q, and the rules for calculating the value E are predetermined, and the parameters or Q values ​​to be used in the rules can be predefined according to the decoding mode.

[0256] The receiver determines a rate matching method among puncturing, shortening, and repetition applied in the transmitter to support optimal polar decoding performance based on the K, N, and E values, and determines a polar code sequence accordingly (1055). Here, if a transformation of the polar code sequence is required based on the N value, the receiver can apply the transformation to determine the polar code sequence (1055).

[0257] Once the above polar code sequence and rate matching method are determined, the receiver must perform rate dematching corresponding to the rate matching (1057). Here, rate dematching means one of the following methods.

[0258] - When the rate matching method is puncturing, a method for determining a decoder input value corresponding to a total of N bits consisting of demodulated LLR values ​​of E bits and values ​​set to LLR = 0 corresponding to punctured bits of (N - E) bits.

[0259] - In case the rate matching method is shortening, a method of determining the decoder input value corresponding to a total of N bits composed of the demodulated LLR values ​​of E bits and the values ​​set to LLR = LLR_max corresponding to the shortened bits of (N - E) bits (since the shortened bits are usually set to 0, the receiver processes them as if it received a bit that is definitely 0, even if there is no signal component for the shortened bits)

[0260] - In case the rate matching method is repeated, a method of combining the demodulated LLR values ​​for each repeated bit of (E - N) bits.

[0261] Once rate dematching is performed (1057), the receiver can perform (N, K) polar decoding based on the determined polar code sequence (1059).

[0262] The two-stage data structure proposed in this disclosure does not impose any specific restrictions. For example, if both the first and second information are L1 signaling information, the first information may include information about the second information, and the second information may indicate parameters related to encoding and decoding methods for the third information. Here, the third information may be data corresponding to general content transmitted via a data channel or a channel called a physical layer pipe (PLP) for data transmission.

[0263] The present disclosure can be applied to a broadcasting system as well as a communication system that supports intelligent services (e.g., smart home, smart building, smart city, smart car or connected car, healthcare, digital education, retail, security and safety-related services, etc.) based on 5G / 6G communication technology and IoT-related technology.

[0264] The methods according to the embodiments described in the claims or specification of the present disclosure may be implemented in the form of hardware, software, or a combination of hardware and software. If implemented in software, a computer-readable storage medium storing one or more programs (software modules) may be provided. The one or more programs stored in the computer-readable storage medium are configured for execution by one or more processors within an electronic device. The one or more programs include instructions that cause the electronic device to execute the methods according to the embodiments described in the claims or specification of the present disclosure.

[0265] These programs (software modules, software) may be stored in random access memory, non-volatile memory including flash memory, read only memory (ROM), electrically erasable programmable read only memory (EEPROM), magnetic disc storage device, compact disc ROM (CD-ROM), digital versatile discs (DVDs) or other forms of optical storage device, magnetic cassette. Or, they may be stored in a memory configured as a combination of some or all of these. In addition, each configuration memory may be included in multiple numbers.

[0266] Additionally, the program may be stored in an attachable storage device that is accessible via a communication network such as the Internet, an intranet, a local area network (LAN), a wide local area network (WLAN), a storage area network (SAN), or a combination thereof. Such a storage device may be connected to a device performing an embodiment of the present disclosure via an external port. Additionally, a separate storage device on the communication network may be connected to a device performing an embodiment of the present disclosure.

[0267] In the specific embodiments of the present disclosure 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 disclosure is not limited to singular or plural components. Components expressed in the plural form may be composed of singular elements, or components expressed in the singular form may be composed of plural elements.

[0268] While the detailed description of this disclosure has described specific embodiments, it should be understood that various modifications are possible without departing from the scope of this disclosure. Therefore, the scope of this disclosure should not be limited to the described embodiments, but should be defined not only by the scope of the claims described below, but also by equivalents thereof.

Claims

1. In a method performed by a transmitter in a communication system, A step of identifying a first encoding mode for encoding first information bits and a second encoding mode for encoding second information bits; A step of confirming a first polar code sequence for encoding first information based on the first encoding mode; A step of generating first polar encoding bits by polar encoding first information based on the determined first polar encoding sequence; A step of selecting at least some of the first polar encoding bits; A step of determining the length (E) of bits allocated to transmit the encoded second information bits based on the length (K) of the second information bits; A step of determining a rate matching method to be applied to the second information bits and a second polar code sequence based on the second encoding mode, the length (K) of the second information bits, and the length (E) of the allocated bits; A step of generating second polar encoding bits by polar encoding the second information bits based on the determined second polar encoding sequence; A step of performing rate matching based on the determined rate matching method for the generated second polar encoding bits; A step of generating modulation symbols based on at least some of the first polar encoding bits and the second polar encoding bits to which the rate matching is applied; A step of generating a signal based on the generated modulation symbols; and A step of transmitting the generated signal is included, A method characterized in that the first information bits have a fixed length, and the first information bits contain information about the length (K) of the second information bits.

2. In paragraph 1, The first polar code sequence and the second polar code sequence are, A method characterized in that the length of each polar code is determined from a single polar code sequence having the same polar code sequence or a nested structure.

3. In paragraph 1, A method characterized in that a spectral efficiency corresponding to at least some of the first polar encoding bits is lower than a spectral efficiency corresponding to the second polar encoding bits to which the rate matching is applied.

4. In paragraph 1, The above rate matching method is one of perforation, shortening, and repetition. A method characterized in that the first encoding mode and the second encoding mode are indicated based on one indicator.

5. In a method performed by a receiver in a communication system, A step of receiving a signal corresponding to first information bits and second information bits; A step of performing demodulation based on the received signal; A step of checking a first encoding mode applied by the transmitter to decode first information bits and a second encoding mode applied by the transmitter to decode second information bits based on the received signal; A step of confirming a first polar code sequence for decoding first information based on the first encoding mode; A step of processing the demodulated values ​​corresponding to the punctured bits among the first polar encoding bits generated based on the first information bits as loss; A step of performing polar decoding based on the demodulated values ​​corresponding to the first polar code sequence and the first information bits and the values ​​processed as loss; A step of determining the length (K) of second information bits based on the first information bits determined above; A step of determining the length (E) of bits allocated to transmit the encoded second information bits from the transmitter based on the length (K) of the second information bits determined above; A step of determining a rate matching method and a second polar code sequence applied to the second information bits in the transmitter based on the second encoding mode, the length (K) of the determined second information bits, and the length (E) of the allocated bits; and A method characterized by comprising a step of performing polar decoding based on the determined second polar code sequence and demodulated values ​​corresponding to the second information bits.

6. In paragraph 5, The first polar code sequence and the second polar code sequence are, A method characterized in that the length of each polar code is determined from a single polar code sequence having the same polar code sequence or a nested structure.

7. In paragraph 5, The step of performing polar decoding based on the determined second polar code sequence and the demodulated values ​​corresponding to the second information bits is as follows: If the rate matching method applied to the above second information bits is perforation, A step of determining demodulated values ​​corresponding to the punctured bits among the second polar encoding bits generated based on the second information from the transmitter as 0; A step of performing polar decoding based on the demodulated values ​​corresponding to the second polar code sequence and the second information bits and the demodulated values ​​corresponding to the punctured bits; and If the rate matching method applied to the above second information bits is a shortened one, A step of processing demodulated values ​​corresponding to shortened bits among the second polar coded bits generated based on the second information from the transmitter into values ​​corresponding to the probability that the shortened bit is 0 with 1; and A step of performing polar decoding based on the demodulated values ​​corresponding to the second polar code sequence and the second information bits and the values ​​corresponding to the shortened bit having a probability of 1 being 0, If the rate matching method applied to the above second information bits is iterative, A step of combining demodulation values ​​corresponding to repeated bits among the second polar encoding bits generated based on the second information from the transmitter into one value each; A method characterized by further comprising the step of performing polar decoding based on the demodulated values ​​corresponding to the second polar code sequence and the second information bits and the combined values.

8. In paragraph 5, The first encoding mode and the second encoding mode are indicated based on one indicator, The process of processing the above loss is characterized in that the demodulated value of the perforated bits is determined as LLR (log-likelihood ratio) = 0.

9. In a transmitter in a communication system, Transmitter and receiver; and Includes a control unit connected to the above transmitter and receiver, The above control unit, Identify a first encoding mode for encoding the first information bits and a second encoding mode for encoding the second information bits, Identifying a first polar code sequence for encoding first information based on the first encoding mode; Generating first polar encoding bits by polar encoding the first information based on the first polar encoding sequence determined above, Select at least some of the first polar encoding bits, Determine the length (E) of bits allocated to transmit the encoded second information bits based on the length (K) of the second information bits, Determine a rate matching method and a second polar code sequence to be applied to the second information bits based on the second encoding mode, the length (K) of the second information bits, and the length (E) of the allocated bits, Generating second polar encoded bits by polar encoding the second information bits based on the second polar code sequence determined above, Rate matching is performed based on the determined rate matching method for the generated second polar encoding bits, Generating modulation symbols based on at least some of the first polar encoding bits and the second polar encoding bits to which the rate matching is applied, Generate a signal based on the above generated modulation symbols, Transmit the generated signal, A transmitter characterized in that the first information bits have a fixed length, and the first information bits contain information about the length (K) of the second information bits.

10. In paragraph 9, The first polar code sequence and the second polar code sequence are, A transmitter characterized in that the length of each polar code is determined from one polar code sequence having the same polar code sequence or a nested structure.

11. In paragraph 9, The spectral efficiency corresponding to at least some of the first polar coded bits is lower than the spectral efficiency corresponding to the second polar coded bits to which the rate matching is applied, The above rate matching method is one of perforation, shortening, and repetition. A transmitter characterized in that the first encoding mode and the second encoding mode are indicated based on one indicator.

12. In a receiver in a communication system, Transmitter and receiver; and Includes a control unit connected to the above transmitter and receiver, The above control unit, Receive signals corresponding to first information bits and second information bits, Demodulation is performed based on the received signal, Based on the received signal, the first encoding mode applied by the transmitter to decode the first information bits and the second encoding mode applied by the transmitter to decode the second information bits are checked, Identifying a first polar code sequence for decoding the first information based on the first encoding mode; Among the first polar encoding bits generated based on the first information bits, the demodulated values ​​corresponding to the punctured bits are processed as lost, Perform polar decoding based on the first polar code sequence and the demodulated values ​​corresponding to the first information bits and the values ​​processed as loss, Determine the length (K) of the second information bits based on the first information bits determined above, Based on the length (K) of the second information bits determined above, the length (E) of bits allocated to transmit the encoded second information bits is determined by the transmitter, The transmitter determines a rate matching method and a second polar code sequence applied to the second information bits based on the second encoding mode, the length (K) of the determined second information bits, and the length (E) of the allocated bits, A receiver characterized in that polar decoding is performed based on the determined second polar code sequence and demodulated values ​​corresponding to the second information bits.

13. In paragraph 12, The first polar code sequence and the second polar code sequence are, A receiver characterized in that the length of each polar code is determined from one polar code sequence having the same polar code sequence or a nested structure.

14. In paragraph 12, The above control unit, If the rate matching method applied to the above second information bits is perforation, Among the second polar coded bits generated based on the second information from the transmitter, the demodulated values ​​corresponding to the punctured bits are determined as 0, Polar decoding is performed based on the second polar code sequence and the demodulated values ​​corresponding to the second information bits and the demodulated values ​​corresponding to the punctured bits, If the rate matching method applied to the above second information bits is a shortened one, Among the second polar coded bits generated from the transmitter based on the second information, the demodulated values ​​corresponding to the shortened bits are processed as values ​​corresponding to the probability that the shortened bit is 0 with 1, Polar decoding is performed based on the demodulated values ​​corresponding to the second polar code sequence and the second information bits and the values ​​corresponding to the shortened bit having a probability of 1 being 0, If the rate matching method applied to the above second information bits is iterative, The demodulation values ​​corresponding to the repeated bits among the second polar coded bits generated based on the second information from the transmitter are combined into one value each, A receiver characterized in that polar decoding is performed based on the demodulated values ​​corresponding to the second polar code sequence and the second information bits and the combined values.

15. In paragraph 12, The first encoding mode and the second encoding mode are indicated based on one indicator, A receiver characterized in that the process of processing the above loss determines the demodulated value of the punctured bits as LLR (log-likelihood ratio) = 0.

Images