Retransmission method of multi-level coded modulation system and multi-level coded modulation system

Abstract

The invention provides a retransmission method of a multi-level coded modulation system and the multi-level coded modulation system, and belongs to the technical field of communication. In the retransmission method of the multi-level coded modulation system, a sending end obtains a first retransmission signal NACK from a receiving end, and based on the first NACK, N transmission layers of a to-be-transmitted bit stream are respectively retransmitted for J times by adopting an incremental redundancy mode, so that the receiving end combines a first bit stream and a second bit stream corresponding to a first target transmission layer, and obtaining a third bit stream corresponding to the first target transmission layer, and demodulating and decoding the third bit stream, the first target transmission layer being any one of the N transmission layers. According to the invention, by increasing the flexibility of retransmission technology application in the multi-level coding modulation system, the gain of the multi-level coding modulation system is improved, and the reliability of data transmission of the multi-level coding modulation system is improved, so that a coding layer without a code rate compatibility characteristic can also adopt an IR mode, and the performance of the multi-level coding modulation system is improved.

Description

Technical Field

[0001] The present application relates to the field of communication technologies, and in particular, to a retransmission method for a multi-level coded modulation system and a multi-level coded modulation system. Background Art

[0002] In the field of communication technologies, when data is transmitted through a channel, it will be affected by various noises, resulting in errors in the transmitted data and affecting the communication effect. Therefore, the Hybrid Automatic Repeat Request (HARQ) technology has emerged. The HARQ technology is widely used in communication systems to solve the problem of errors in transmitted data. HARQ is a new type of communication technology that combines the advantages of Automatic Repeat Request (ARQ) and forward error correction (FEC) technologies and overcomes their respective disadvantages. It can effectively improve the link throughput rate, better resist interference and fading, improve the system effectiveness and the reliability of data transmission, and has strong practicability.

[0003] In a traditional Bit Interleaved Coded Modulation (BICM) system, data is encoded at the sending end and sent to the receiving end. In this process, if a relatively complex coding method is used for the data, the complexity of channel transmission information is relatively high, the burden on the communication system is heavy, and the performance is often affected. In the prior art, the Multi-Level Coded Modulation (MLCM) technology is adopted. It is a communication method that combines multi-level coding and modulation technologies. By stratifying the data to use different complexity coding methods, it can effectively reduce the complexity of channel transmission information and enhance the performance of information transmission. In some scenarios, MLCM can obtain better performance.

[0004] The HARQ technology is divided into two categories: the Incremental Redundancy (IR) method and the Chase Combining (CC) method. The difference between these two categories is that in the CC method, the sending end retransmits the same data packet each time. When the receiving end receives a new packet, it directly superimposes and combines it with the initially transmitted data packet and decodes on this basis until the decoding is successful or the maximum number of retransmissions is reached; while in the IR method, redundant information is newly added to the retransmitted data packet, and the amount of redundant information for each retransmission is different. In the IR method, combining the initially transmitted and retransmitted data packets can form a codeword with a lower code rate, thereby obtaining a greater coding gain and achieving the purpose of increasing redundancy.

[0005] Therefore, when the CC method is adopted, the gain obtained by applying the HARQ technology in the MLCM system is smaller than that obtained by the IR method, resulting in limited performance improvement of the HARQ technology for the entire system. However, if the IR method is to be applied, there will be a mismatch between the coding method and the IR method in the multilevel coded modulation system, which limits the application of the HARQ technology in the MLCM system. Summary of the Invention

[0006] This application provides a retransmission method for a multilevel coded modulation system and a multilevel coded modulation system to solve the problem that the existing HARQ technology is limited in use in the MLCM system.

[0007] In a first aspect, this application provides a retransmission method for a multilevel coded modulation system, which is applied to a multilevel coded modulation system. The method includes:

[0008] The sending end obtains a first retransmission signal NACK from the receiving end;

[0009] Based on the first NACK, the sending end performs J retransmissions on N transmission layers of the to-be-transmitted bit stream in an incremental redundancy manner, so that the receiving end merges the first bit stream S n (j - 1) and the second bit stream S n (j) corresponding to the first target transmission layer to obtain a third bit stream corresponding to the first target transmission layer, and demodulates and decodes the third bit stream; where N and J are both positive integers, and N≥2, J≥1; the first target transmission layer is any one of the N transmission layers; the second bit stream S n (j) includes the first bit stream S n (j - 1) and redundant information, n is the serial number of the N transmission layers, 1≤n≤N, j is the retransmission times of the nth transmission layer, 0<j<J.

[0010] In a possible design, before the sending end obtains the first retransmission signal NACK from the receiving end, the method further includes:

[0011] The sending end performs an initial transmission on the N transmission layers, and at least one of the N transmission layers is encoded using a forward error correction code.

[0012] In a possible design, before the sending end performs an initial transmission on the N transmission layers, the method further includes:

[0013] The sending end stratifies the to-be-transmitted bit stream based on the signal-to-noise ratio of the to-be-transmitted bit stream to obtain the N transmission layers corresponding to the to-be-transmitted bit stream. The N transmission layers are respectively a low-density parity-check LDPC layer, a forward error correction coding BCH layer, and an uncoded NC layer.

[0014] In a possible design, the sender stratifies the to-be-transmitted bitstream based on the signal-to-noise ratio of the to-be-transmitted bitstream, to obtain the N transmission layers corresponding to the to-be-transmitted bitstream, including:

[0015] The sender encapsulates the bitstream in the to-be-transmitted bitstream with a signal-to-noise ratio less than or equal to a first preset signal-to-noise ratio into an LDPC layer, and the bitstream in the LDPC layer is LDPC-encoded;

[0016] The sender encapsulates the bitstream in the to-be-transmitted bitstream with a signal-to-noise ratio greater than the first preset signal-to-noise ratio and less than or equal to a second preset signal-to-noise ratio into a BCH layer, and the bitstream in the BCH layer is BCH-encoded;

[0017] The sender encapsulates the bitstream in the to-be-transmitted bitstream with a signal-to-noise ratio greater than the second preset signal-to-noise ratio into an NC layer, and the bitstream in the NC layer is not encoded.

[0018] In a possible design, when the sender performs an initial transmission on the first target transmission layer, it sends a first bitstream S n (j - 1) to the receiver, and when the sender performs a first retransmission on the first target transmission layer, it sends a second bitstream S n (j).

[0019] In a second aspect, the present application provides a retransmission method for a multilevel coding modulation system, which is applied to a multilevel coding modulation system. The method includes:

[0020] The receiver sends a first retransmission signal NACK to the sender;

[0021] When the sender, based on the first NACK, uses the incremental redundancy method to perform J retransmissions on the N transmission layers of the to-be-transmitted bitstream respectively, the receiver combines the first bitstream S n (j - 1) and the second bitstream S n (j) corresponding to the first target transmission layer to obtain a third bitstream corresponding to the first target transmission layer, and demodulates and decodes the third bitstream; where N and J are both positive integers, and N ≥ 2, J ≥ 1; the first target transmission layer is any one of the N transmission layers; the second bitstream S n (j) includes the first bitstream S n (j - 1) and redundant information, n is the serial number of the N transmission layers, 1 ≤ n ≤ N, j is the retransmission times of the nth transmission layer, 0 < j < J.

[0022] In a possible design, the receiver processes the first bitstream S n(j - 1) and the second bitstream S n (j) are combined to obtain the third bitstream corresponding to the first target transport layer, and demodulation and decoding are performed on the third bitstream, including:

[0023] The receiving end performs quadrature amplitude modulation and demodulation (QAM demodulation) on the first bitstream S n (j - 1) to obtain the first log-likelihood ratio (LLR);

[0024] The receiving end performs QAM demodulation on the second bitstream S n (j) to obtain the second LLR;

[0025] The receiving end combines the first LLR and the second LLR to obtain the third LLR, and performs LDPC decoding on the third LLR.

[0026] In a possible design, the method further includes:

[0027] When the receiving end decodes a codeword error in at least one transport layer among the N transport layers, the receiving end sends a second NACK to the sending end; the second NACK is used to indicate that all N transport layers perform retransmission, or the second NACK is used to indicate that a second target transport layer performs retransmission, and the second target transport layer is the transport layer in which a codeword decoding error occurs among the N transport layers.

[0028] In a possible design, the method further includes:

[0029] When the receiving end has a demodulation and decoding error in the first target transport layer, the receiving end stores the decoding results of the transport layers that have been successfully decoded into a buffer;

[0030] When the receiving end decodes the transport layer corresponding to the decoding results stored in the buffer, the receiving end calls the decoding results in the buffer.

[0031] In a third aspect, the present application provides a communication device, including: a module for executing the method embodiments of the foregoing first aspect, or a module for executing the method embodiments of the foregoing second aspect.

[0032] In a fourth aspect, the present application provides an electronic device, including: a memory and at least one processor;

[0033] The memory stores computer-executable instructions;

[0034] The at least one processor executes the computer-executable instructions stored in the memory, so that the at least one processor executes the method as described in the foregoing first aspect, various possible designs of the first aspect, the second aspect, or various possible designs of the second aspect.

[0035] In a fifth aspect, an embodiment of the present application provides a computer-readable storage medium storing computer-executable instructions, which, when executed, implement the method described in the first aspect above, all possible designs of the first aspect, the second aspect, or all possible designs of the second aspect.

[0036] In a sixth aspect, the present application provides a computer program product including computer program code, which, when running on a computer, causes the computer to implement the method described in the first aspect above, all possible designs of the first aspect, the second aspect, or all possible designs of the second aspect.

[0037] In a seventh aspect, the present application provides a chip including: an interface circuit and a logic circuit. The interface circuit is configured to receive a signal from another chip outside the chip and transmit it to the logic circuit, or send a signal from the logic circuit to another chip outside the chip. The logic circuit is configured to implement the method described in the first aspect above, all possible designs of the first aspect, the second aspect, or all possible designs of the second aspect.

[0038] An embodiment of the present application provides a retransmission method for a multi-level coded modulation system and a multi-level coded modulation system. In the retransmission method of the multi-level coded modulation system, a sending end obtains a first retransmission signal NACK from a receiving end, and based on the first NACK, performs J retransmissions on N transmission layers of a to-be-transmitted bitstream in an incremental redundancy manner, so that the receiving end combines a first bitstream and a second bitstream corresponding to a first target transmission layer to obtain a third bitstream corresponding to the first target transmission layer, and demodulates and decodes the third bitstream. The first target transmission layer is any one of the N transmission layers. The present application improves the gain of the multi-level coded modulation system by increasing the flexibility of the application of the retransmission technology HARQ in the multi-level coded modulation system, and at the same time increases the reliability of data transmission in the multi-level coded modulation system, enabling coding layers without code rate compatibility characteristics to also adopt the IR method. By adopting the IR method, in addition to obtaining the energy gain and diversity gain of retransmission, an additional net code rate gain brought by the code rate reduction can be obtained, which can improve the link throughput and further enhance the performance of the multi-level coded modulation system. BRIEF DESCRIPTION OF THE DRAWINGS

[0039] Figure 1 is a schematic flowchart of a retransmission method for a multi-level coded modulation system provided by an embodiment of the present application;

[0040] Figure 2 is a schematic structural diagram of N transmission layers when a sending end performs an initial transmission and J retransmissions on N transmission layers provided by an embodiment of the present application;

[0041] Figure 3 A schematic diagram of the structures of the LDPC layer and the BCH layer during the initial transmission and the J - th re - transmission by the transmitting end provided by an embodiment of the present application;

[0042] Figure 4 A schematic diagram of the structure of the NC layer during the initial transmission and the J - th re - transmission by the transmitting end provided by an embodiment of the present application;

[0043] Figure 5 A schematic diagram of the demodulation and decoding process of the receiving end provided by an embodiment of the present application;

[0044] Figure 6 A simulation diagram of the 256QAM - 404 layering scheme provided by an embodiment of the present application;

[0045] Figure 7 A schematic diagram of the structure of a communication device provided by an embodiment of the present application;

[0046] Figure 8 Another schematic diagram of the structure of a communication device provided by an embodiment of the present application;

[0047] Figure 9 A schematic diagram of the structure of an electronic device provided by an embodiment of the present application. Detailed implementation manners

[0048] To make the objectives, technical solutions, and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present application. Obviously, the described embodiments are some, but not all, of the embodiments of the present application. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present application without making creative efforts fall within the scope of protection of the present application.

[0049] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs; the terms used in the specification of this application are only for the purpose of describing specific embodiments and are not intended to limit this application; the terms "including" and "having" and any variations thereof in the specification, claims, and drawings of this application are intended to cover non - exclusive inclusion.

[0050] Reference to "embodiment" in this document means that the specific features, structures, or characteristics described in connection with the embodiment may be included in at least one embodiment of the present application. The phrase "embodiment" appearing at various positions in the specification does not necessarily refer to the same embodiment, nor are they independent or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by those skilled in the art that the embodiments described herein may be combined with other embodiments.

[0051] The term "and / or" in this document is merely a description of the association relationship of associated objects, indicating that there can be three relationships. For example, A and / or B can represent: the existence of A, the simultaneous existence of A and B, and the existence of B. Additionally, the character " / " in this document generally indicates that the associated objects before and after are in an "or" relationship.

[0052] Furthermore, terms such as "first", "second", etc. in the specification and claims of this application or in the above-mentioned drawings are used to distinguish different objects, rather than to describe a specific order, and may explicitly or implicitly include one or more of such features.

[0053] In the description of this application, unless otherwise specified, the meanings of "a plurality" and "at least two" refer to more than two (including two). Similarly, "multiple groups" and "at least two groups" refer to more than two groups (including two groups).

[0054] In the description of this application, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "coupled" should be understood in a broad sense. For example, "connected" or "coupled" can refer not only to a physical connection, but also to an electrical connection or a signal connection. For example, it can be a direct connection, that is, a physical connection, or it can be indirectly connected through at least one intermediate element, as long as the circuit is connected. It can also be the connection inside two elements; a signal connection can refer not only to a signal connection through a circuit, but also to a signal connection through a media medium, such as radio waves. For those of ordinary skill in the art, the specific meanings of the above terms in this application can be understood according to specific circumstances.

[0055] To enable those skilled in the art to better understand the solution of this application, the technical solutions in the embodiments of this application will be clearly and completely described below in conjunction with the accompanying drawings. It should be noted that, without conflict, different technical features in this application can be combined with each other.

[0056] First, the noun terms involved in one or more embodiments of this specification are explained.

[0057] Low-density Parity-check (LDPC) is a forward error correction coding technique commonly used in communication systems to improve the reliability of data transmission.

[0058] Bose-Chaudhuri-Hocquenghem (BCH) error correction coding is a powerful error correction code widely used in the storage and communication fields, capable of correcting multiple bit errors.

[0059] No Coding (NC) is used to directly transmit bits that are not prone to errors without coding, which can reduce the system complexity without affecting the reliability.

[0060] Next, the implementation background of the technical solution provided by the embodiments of this application will be introduced.

[0061] All along, people's interest in mobile wireless channels has been increasing, and they have begun to consider the coding modulation problem of fading channels. Nowadays, BICM has become a typical coding modulation technology widely used in various communication systems. With its advantages of simple structure and excellent performance, it has increased the coding diversity and the disadvantage of poor performance in fading channels, which has always been a relatively hot research issue in the communication field.

[0062] The 5G system adopts BICM as the coding modulation scheme, while 6G requires a larger bandwidth, more antennas, and a larger signal constellation to achieve better performance. Therefore, the requirement for the throughput of the system is increasing day by day. The MLCM technology is a communication method that combines multi-level coding and modulation techniques. By stratifying data to use different complexity coding methods, it can effectively reduce the complexity of channel transmission information and enhance the performance of information transmission. In some scenarios, MLCM can obtain better performance.

[0063] In the communication field, communication systems are often affected by various noises during the transmission process, resulting in transmission errors. The existing solutions mainly introduce error control techniques. When a transmission attempt fails once, the data packet is required to be retransmitted. Such a transmission mechanism is called Automatic Repeat reQuest (ARQ).

[0064] In a wireless transmission environment, channel noise, fading caused by mobility, and interference from other users result in poor channel transmission quality. Therefore, data packets should be protected to suppress various interferences. This protection mainly uses forward error correction coding (FEC), which transmits additional bits in the packet. FEC is a forward error correction technology that uses data to transmit redundant information. That is, the signal is pre-encoded according to a certain algorithm before being sent into the transmission channel, and redundant codes with the characteristics of the signal itself are added. At the receiving end, the received signal is decoded according to the corresponding algorithm to find the error codes generated during transmission and correct them. FEC codes must minimize the use of redundant bits while ensuring error correction performance, which has high requirements. Therefore, it is cost-effective, can reduce the bit error rate, and can save the bandwidth that would otherwise be used for retransmission. However, too much forward error correction coding will reduce the transmission efficiency.

[0065] Therefore, hybrid automatic repeat request (HARQ) emerged. The HARQ scheme is a new communication technology that combines the advantages of FEC and ARQ and overcomes their respective disadvantages. By combining error correction coding technology and retransmission technology, it can improve the link throughput rate and has better anti-interference and anti-fading capabilities.

[0066] When using the MLCM scheme system, there are also phenomena such as being unable to solve signal transmission problems and insufficient gain. In existing solutions, the application of HARQ technology is often ignored. When applying HARQ technology in the MCLM system, the IR-HARQ scheme can obtain an additional net coding gain brought by the reduced code rate, so it has better retransmission performance than the CC-HARQ scheme. However, the channel coding in the transport layer must have the "rate compatible" characteristic, which limits the application of HARQ to a certain extent, and the system performance improvement is limited.

[0067] Based on the problems existing in the related technologies, the present application provides a retransmission method for a multi-level coded modulation system and a multi-level coded modulation system. In the retransmission method of the multi-level coded modulation system, the sending end obtains a first retransmission signal NACK from the receiving end, and based on the first NACK, uses the incremental redundancy method to perform J retransmissions on N transmission layers of the to-be-transmitted bit stream respectively, so that the receiving end merges a first bit stream and a second bit stream corresponding to a first target transmission layer to obtain a third bit stream corresponding to the first target transmission layer, and demodulates and decodes the third bit stream. The first target transmission layer is any one of the N transmission layers. The present application improves the gain of the multi-level coded modulation system by increasing the flexibility of the application of the retransmission technology HARQ in the multi-level coded modulation system, and at the same time increases the reliability of data transmission in the multi-level coded modulation system, enabling coding layers without the code rate compatibility characteristic to also adopt the IR method. In addition to obtaining the energy gain and diversity gain of retransmission by adopting the IR method, an additional net code rate gain brought by the reduction of the code rate can also be obtained, which can improve the link throughput rate and further improve the performance of the multi-level coded modulation system.

[0068] Next, through some specific embodiments and accompanying drawings, the present application will be introduced in detail on how to solve the problem that the HARQ technology is limited in use in the MLCM system.

[0069] Figure 1 It is a schematic flowchart of a retransmission method for a multi-level coded modulation system provided by an embodiment of the present application. As Figure 1 shown, the retransmission method for the multi-level coded modulation system provided by the embodiment of the present application specifically includes S101 and S102, and S101 and S102 are described in detail below.

[0070] S101: The receiving end sends a first retransmission signal NACK to the sending end. Correspondingly, the sending end obtains the first retransmission signal NACK from the receiving end.

[0071] Among them, the first retransmission signal NACK is a negative feedback. The receiving end sends the first retransmission signal NACK to the sending end when it does not receive the data or the received data is incorrect.

[0072] S102: Based on the first NACK, the sending end uses the incremental redundancy method to perform J retransmissions on N transmission layers of the to-be-transmitted bit stream respectively, so that the receiving end merges a first bit stream S n (j - 1) and a second bit stream S n (j) corresponding to the first target transmission layer to obtain a third bit stream corresponding to the first target transmission layer, and demodulates and decodes the third bit stream; where N and J are both positive integers, and N≥2, J≥1; the first target transmission layer is any one of the N transmission layers; the second bit stream S n (j) includes the first bit stream Sn (j - 1) and redundant information, where n is the sequence number of the N transport layers, 1 ≤ n ≤ N, j is the number of retransmissions of the nth transport layer, and 0 < j < J.

[0073] In a possible embodiment, before S101, where the receiving end sends a first retransmission signal NACK to the sending end, the method further includes Sa, which is described in detail below.

[0074] Sa: The sending end performs an initial transmission on the N transport layers, and at least one of the N transport layers is encoded using a forward error correction code.

[0075] Among them, each of the N transport layers can be named using the encoding method of that transport layer, or can be named in other ways, and this embodiment does not make specific limitations in this regard.

[0076] For example, the number of transport layers is three. One of the three transport layers uses the LDPC encoding method, another transport layer uses the BCH encoding method, and the third transport layer is not encoded. At this time, the N transport layers are the LDPC layer, the BCH layer, and the NC layer respectively.

[0077] It should be noted that when the sending end performs an initial transmission on the N transport layers, all of the N transport layers can be encoded using a forward error correction code, or some of them can be encoded using a forward error correction code, and this embodiment does not make specific limitations in this regard.

[0078] For example, the N transport layers are the LDPC layer, the BCH layer, and the NC layer respectively. When the sending end performs an initial transmission on the N transport layers, the LDPC layer, the BCH layer, and the NC layer are all encoded using a forward error correction code.

[0079] Another example, the N transport layers are the LDPC layer, the BCH layer, and the NC layer respectively. When the sending end performs an initial transmission on the N transport layers, the LDPC layer is encoded using a forward error correction code, and the BCH layer and the NC layer are both encoded using other methods.

[0080] Another example, the N transport layers are the LDPC layer, the BCH layer, and the NC layer respectively. When the sending end performs an initial transmission on the N transport layers, the BCH layer is encoded using a forward error correction code, and the LDPC layer and the NC layer are both encoded using other methods.

[0081] In a possible embodiment, before Sa, where the sending end performs an initial transmission on the N transport layers, the method further includes Sc, which is described in detail below.

[0082] Sc: The sending end stratifies the bitstream to be transmitted based on the signal-to-noise ratio of the bitstream to be transmitted, and obtains N transport layers corresponding to the bitstream to be transmitted.

[0083] Among them, the N transport layers are respectively a Low-Density Parity-Check (LDPC) layer, a Bose-Chaudhuri-Hocquenghem (BCH) error-correcting coding layer, and a Non-Coding (NC) layer.

[0084] In a possible embodiment, Sc, the sending end stratifies the bit stream to be transmitted based on the signal-to-noise ratio of the bit stream to be transmitted, obtaining N transport layers corresponding to the bit stream to be transmitted, which can be specifically implemented through Sc1 to Sc3. The following gives a detailed description of Sc1 to Sc3.

[0085] Sc1, the sending end encapsulates the bit stream in the bit stream to be transmitted with a signal-to-noise ratio less than or equal to the first preset signal-to-noise ratio into the LDPC layer, and the bit stream in the LDPC layer uses LDPC coding.

[0086] Among them, the first preset signal-to-noise ratio can be set by the user himself, and this embodiment does not make specific limitations on this.

[0087] Sc2, the sending end encapsulates the bit stream in the bit stream to be transmitted with a signal-to-noise ratio greater than the first preset signal-to-noise ratio and less than or equal to the second preset signal-to-noise ratio into the BCH layer, and the bit stream in the BCH layer uses BCH coding.

[0088] Among them, the second preset signal-to-noise ratio can be set by the user himself, and this embodiment does not make specific limitations on this.

[0089] It should be noted that the second preset signal-to-noise ratio is greater than the first preset signal-to-noise ratio.

[0090] Sc3, the sending end encapsulates the bit stream in the bit stream to be transmitted with a signal-to-noise ratio greater than the second preset signal-to-noise ratio into the NC layer, and the bit stream in the NC layer is not encoded.

[0091] In a possible embodiment, when the sending end performs an initial transmission of the first target transport layer, it sends the first bit stream S n (j - 1) to the receiving end. When the sending end performs a first retransmission of the first target transport layer, it sends the second bit stream S n (j).

[0092] It should be noted that when the sending end performs an initial transmission of the LDPC layer, the first bit stream S n (j - 1) sent by the sending end to the receiving end is S1(0); when the sending end performs an initial transmission of the LDPC layer, the second bit stream S n (j) sent by the sending end to the receiving end is S1(1); the receiving end combines S1(0) and S1(1), and a LDPC code with a lower actual code rate can be obtained.

[0093] It should be noted that when the sending end performs an initial transmission of the BCH layer, the first bit stream S n(j - 1) is S2(0); when the BCH layer is initially transmitted at the sending end, the second bitstream S sent by the sending end to the receiving end n (j) is S2(1); S2(1) has additional redundant information compared to S2(0), and the receiving end combines S2(0) and S2(1).

[0094] It should be noted that when the NC layer is initially transmitted at the sending end, the first bitstream S sent by the sending end to the receiving end n (j - 1) is S3(0); when the NC layer is initially transmitted at the sending end, the second bitstream S sent by the sending end to the receiving end n (j) is S3(1); S3(1) has additional redundant information compared to S3(0), and the receiving end combines S3(0) and S3(1).

[0095] Specifically, the core idea of this application is that IR - HARQ can be applied in each coding layer, enabling each layer to obtain the diversity gain and the net coding gain brought by the reduced code rate. For the LDPC layer, since the LDPC code has the code rate adaptation characteristic, IR - HARQ can be used normally; but for other coding methods such as the BCH code, to implement IR re - transmission, it is necessary to merge the initially transmitted and re - transmitted codewords.

[0096] The information bit sequence S i enters the multi - level coding modulation system. The sending end divides it into N coding layers, and uses corresponding coding methods respectively. After multi - level coding, they are combined and then subjected to MLC constellation mapping. Then, demodulation and decoding operations are performed on the information bit S after constellation mapping to decode the correct codeword. To improve the system transmission reliability, the HARQ technology is introduced into the multi - level coding system. The sending end decides whether to re - transmit according to the signals (ACK and NACK) fed back by the receiving end, which can improve the reliability of data transmission.

[0097] The difference between the two major types of HARQ methods lies in that in the CC scheme, the sending end re - transmits the same data packet each time. When the receiving end receives a new packet, it directly superimposes and combines it with the initially transmitted data packet, and performs decoding on this basis until the decoding is successful or the maximum number of re - transmissions is reached. In the IR scheme, the re - transmitted data packet is different from the initially transmitted one. The re - transmitted data packet newly adds redundant information, and the amount of redundant information for each re - transmission is different. In the IR method, combining the initially transmitted and re - transmitted data packets can form a codeword with a lower code rate, thereby obtaining a greater coding gain and achieving the purpose of increasing redundancy. Since the IR method can additionally obtain the net coding gain brought by the reduced code rate, it has better re - transmission performance than the CC method. Therefore, the IR - HARQ scheme is adopted for each coding layer in this application, which is achieved through the cooperation between the sending end and the receiving end.

[0098] Figure 2 This is a schematic diagram of the structure of N transport layers during the initial transmission and J retransmissions by the sender in the embodiments of this application. As Figure 2 shown, let layer 1 be the non-coded layer NC layer. Therefore, the bits during the initial transmission are the effective original information. During the first retransmission, redundant information P1 is added, and during the second retransmission, redundant information P2 is added. This is extended to the case of the j-th retransmission. Layer 2 uses the BCH coding method. Since the BCH code itself is also an error-correcting code and contains parity bits, the bit stream structure passing through the BCH layer during the initial transmission is the effective information plus bit positions. During the first retransmission, redundant information P1 is added on this basis, and during the second retransmission, redundant information P2 is added. Layer 3 uses the LDPC coding method, similar to the BCH layer. And for layer 3, due to the code rate compatibility characteristic of the LDPC code itself, the IR retransmission method can be directly used. However, the way for the BCH layer and the NC layer to implement IR retransmission is to merge the previous bit stream and the current retransmission together, regard the previous one as the information part, and the currently added redundant bits as the parity part, and regard the whole as an LDPC code to implement the IR method.

[0099] Regarding the solution provided in this application, it should be noted that the bit stream to be transmitted (information bit sequence S i ) enters the sender of the multi-level coding modulation system as the original data packet. First, it will go through the cyclic redundancy check of the transport block (Transport Block Cyclic Redundancy Check, TB CRC) and the code block segmentation operation, and the data is stratified into n paths of information bits S1, S2, ……, S n , and then different coding processes are performed on the information bits of each transport layer respectively. The number of transport layers and the coding method of each layer can be flexibly set according to the performance requirements of the system to adapt to the requirements of different precision systems. The principle of MLCM is that during the process of mapping data to QAM constellation points, the degree of data protection for different layers is different, that is, the data is divided into bit streams with different channel capacities. That is, in the layer with a high bit channel capacity, more information can be transmitted, while in the layer with a low bit channel capacity, less information is transmitted.

[0100] In the coding structure of this embodiment, a three-layer hierarchical framework is set up, namely the LDPC layer, the BCH layer, and the NC layer, corresponding to low bit channel capacity, medium bit channel capacity, and high bit channel capacity respectively. However, in the actual application of this solution, the coding method of each layer is not limited to LDPC coding and BCH coding, and other error-correcting codes such as turbo codes can also be used. The number of hierarchical layers is not limited to three layers, and it can be migrated to multi-level coding modulation systems with two layers (such as LDPC layer + BCH layer, LDPC layer + NC layer, and BCH layer + NC layer) and above.

[0101] In this embodiment, the bitstream S1 allocated to the LDPC layer will undergo CB CRC, LDPC encoding, rate matching, and bit interleaving operations. The bitstream S2 allocated to the BCH layer will undergo BCH block division, BCH encoding, and interleaving operations. The remaining bitstream S3 of the NC layer is directly transmitted without encoding. The three data streams are combined for MLC constellation mapping, and then demodulation and decoding operations are performed on the information bits S after constellation mapping to decode the correct codeword.

[0102] To improve the reliability of the system, based on the above layering, a hybrid automatic repeat request (HARQ) scheme is added to the system. That is, the HARQ scheme can effectively improve the transmission reliability of the system. In this scheme, the HARQ retransmission mechanism adopts the stop-and-wait protocol. That is, after the sender sends a data packet, it must wait for the feedback signal from the receiver. The feedback signal includes ACK and NACK. When the sender receives an ACK, it normally sends the next data packet. If the received signal is NACK, it means that the data packet is received incorrectly, and the sender needs to retransmit the data packet until the feedback from the receiver is an ACK signal before sending new data. This method can improve the reliability of data transmission.

[0103] There are three types of HARQ combining techniques as follows: The first type of HARQ is to directly discard the received incorrect data and then request retransmission. Naturally, no combination can be performed when the retransmitted data is received, and direct decoding is carried out. The second type of HARQ is a HARQ combining technique with complete incremental redundancy (IR). The received incorrect data is not discarded, and the retransmitted data is completely the encoded redundant part of the data without the original data itself. That is to say, the retransmitted data has no self-decoding function, and the retransmitted redundant data and the incorrect data are combined and then decoded again. The third type of HARQ is the same as the second type of HARQ in that the incorrect data is not discarded and the retransmitted data is combined with the incorrect data. However, the difference is that the retransmitted data of the third type of HARQ has self-decoding function, including both original data and redundant data.

[0104] The third type of HARQ is further divided into two cases: one is the "chase combining" scheme and the other is the "incremental redundancy" scheme. The principle of the chase combining technique is that the transmitting end sends data packets, and the receiving end receives the data packets and first performs cyclic redundancy check (CRC) on them. If an error is found, it first tries to correct the error (FEC). If it still cannot be successfully decoded, the packet is cached and a NACK message is fed back to the transmitting end. The transmitting end receives the NACK and then retransmits the same packet. The receiving end receives the new packet and then superimposes and combines it with the previously cached packet for decoding on this basis until successful decoding or the maximum number of retransmissions is reached, that is, the original data and redundant coded data of the same version are retransmitted to increase the probability of correct decoding. The incremental redundancy technique is to gradually send different redundant versions, reduce the channel coding rate (corresponding to the lower-order redundant coding version), and increase the coding gain. The principle is to first puncture the encoded information and do it at a certain period, and then send it to the receiving end according to the code rate compatibility principle. The transmitting end performs decoding. If the decoding is incorrect, a NACK is fed back to the transmitting end, and the transmitting end retransmits the signal. It should be noted that the signal retransmitted at this time is not the same as the initial transmission, but an information packet after adding redundant information, and the amount of redundant information retransmitted each time is different. The receiving end then performs combined decoding, combines all the previously received bits to form a lower code rate codeword, so as to obtain a greater coding gain and achieve the purpose of increasing redundancy.

[0105] Since the IR method can additionally obtain the net coding gain brought by the code rate reduction, it has better retransmission performance than the CC method. Therefore, the IR-HARQ scheme is adopted for each coding layer in this article. However, using the IR method requires the channel coding of the transport layer to have the rate compatible characteristic, that is, different code rates are obtained by puncturing the codeword. Therefore, the LDPC layer in the embodiment of this technical solution can directly adopt the IR method during retransmission, while the BCH layer and the NC layer flexibly implement the IR method retransmission by virtue of the combination of the initial transmission and the retransmission.

[0106] Taking one retransmission as an example, assume that the initial transmission bitstream of the LDPC layer is S1(0) and the first retransmission bitstream is S1(1). After LDPC encoding, bit puncturing is performed on the bits. Puncturing is to obtain different code rates to adapt to the rate matching process. Specifically, the data is sent to the cyclic buffer after deducting the punctured bits of the first 2z length. z is the spreading factor, and the data of the required length is cyclically selected according to the starting position of the current transmission. In this solution, when the LDPC transport layer information bits are retransmitted, a different starting point from the initial transmission will be selected. To adapt to different information block lengths, the LDPC code sets 8 groups of expansion factors. Taking 2z bits being punctured as an example, the punctured bits are not transmitted over the air interface. Therefore, the starting position of the initial transmission starts after the punctured bits of the LDPC code, and n bits are taken, that is, the starting position of the initial transmission is 2z + 1; after the sender receives a NACK, the retransmitted information bits S1(1) start taking n bits after the position of the initial transmission, that is, the initial position of the retransmission is 2z + 1 + n. S1(0) is an (n,k) code, and S1(1) becomes an (n + n,k) code, and the code rate becomes smaller, so that the retransmission and the initial transmission are concatenated to obtain the optimal IR performance.

[0107] Figure 3 This is a schematic diagram of the structures of the LDPC layer and the BCH layer when the sender performs an initial transmission and J retransmissions on the LDPC layer and the BCH layer provided by an embodiment of the present application. As Figure 3 shown, when the BCH layer performs an initial transmission, the bitstream S2 is BCH-encoded into S2(0). S2(0) includes BCH information bits and BCH parity bits. When performing the first retransmission, redundant information B2 is added to S2(0) to form S2(1), and the data packets of the initial transmission and the first retransmission are combined together: the data packet S2(0) of the initial transmission is regarded as the valid information part of the LDPC code, and the redundant information B2 of the retransmitted data packet is regarded as the parity part of the LDPC code. Then, the IR method can be applied to this transport layer at this time; if the result of the first retransmission is still incorrect and multiple retransmissions are required, it can be applied to a system with J retransmissions. As Figure 3 shown, the initial transmission sequence is the information part A1 and the parity part B1, and new different redundant information such as B2 and B3 is added for each retransmission.

[0108] Figure 4 This is a schematic diagram of the structure of the NC layer when the sender performs an initial transmission and J retransmissions on the NC layer provided by an embodiment of the present application. As Figure 4 shown, the NC layer is similar to the BCH layer, and new redundant information such as B1 and B2 is added for each retransmission, and is combined with the data packet of the previous transmission for demodulation and decoding operations. The difference is that it is not encoded during the initial transmission and is the valid information part during the initial transmission. Therefore, the decoding and demodulation steps at the receiving end are slightly different, which will be elaborated in detail below.

[0109] The embodiment of the present application provides a retransmission method for a multi-level coded modulation system. In this solution, an IR-HARQ technical solution applicable to different coding layers with different coding methods can be applied. For example, coding layers using LDPC coding method, BCH coding method, etc. can all use the IR-HARQ technology through the bit cooperation between the initial transmission and the retransmission.

[0110] The present application provides a retransmission method for a multi-level coded modulation system. The sending end obtains the first retransmission signal NACK from the receiving end, and based on the first NACK, performs J retransmissions on N transmission layers of the to-be-transmitted bit stream in an incremental redundancy manner, so that the receiving end merges the first bit stream and the second bit stream corresponding to the first target transmission layer to obtain the third bit stream corresponding to the first target transmission layer, and demodulates and decodes the third bit stream. The first target transmission layer is any one of the N transmission layers. The present application improves the gain of the multi-level coded modulation system by increasing the flexibility of the application of the retransmission technology HARQ in the multi-level coded modulation system, and at the same time increases the reliability of the data transmitted by the multi-level coded modulation system, enabling coding layers without code rate compatibility characteristics to also adopt the IR method. By adopting the IR method, in addition to obtaining the energy gain and diversity gain of the retransmission, an additional net code rate gain brought by the code rate reduction can also be obtained, which can improve the link throughput and further enhance the performance of the multi-level coded modulation system.

[0111] In a possible embodiment, the receiving end merges the first bit stream S n (j - 1) and the second bit stream S n (j) to obtain the third bit stream corresponding to the first target transmission layer, and demodulates and decodes the third bit stream, which can be implemented through Sd1 to Sd3. The following gives a detailed description of Sd1 to Sd3.

[0112] Sd1: The receiving end performs quadrature amplitude modulation and demodulation (QAM) demodulation on the first bit stream S n (j - 1) to obtain the first log-likelihood ratio (LLR).

[0113] Among them, the log-likelihood ratio (LLR) is a commonly used metric in signal processing and communication systems, especially in the demodulation and signal decision-making processes. LLR is usually used to measure the relative likelihood of an event occurring, especially given the observed data.

[0114] Quadrature amplitude modulation and demodulation (QAM) is a modulation technology that transmits data by adjusting the amplitude and phase of the signal. In QAM, information is modulated by simultaneously controlling the amplitudes of two orthogonal signals (usually the I channel and the Q channel).

[0115] Sd2. The receiving end demodulates the second bitstream S n (j) by QAM demodulation to obtain the second LLR.

[0116] Sd3. The receiving end combines the first LLR and the second LLR to obtain the third LLR, and performs LDPC decoding on the third LLR.

[0117] In a possible embodiment, the method further includes: when the receiving end decodes a codeword error in at least one of the N transport layers, the receiving end sends a second NACK to the sending end; the second NACK is used to indicate that all N transport layers perform retransmission, or the second NACK is used to indicate that the second target transport layer performs retransmission, and the second target transport layer is the transport layer in which the codeword decoding is in error among the N transport layers.

[0118] It should be noted that the transmission efficiency of the QAM modulation method is relatively high, but the system complexity is also relatively high. Therefore, in order to reduce the complexity, if a transport layer makes an error during the current transmission, only the faulty transport layer can be retransmitted during retransmission, and the Quadrature Phase Shift Keying (QPSK) modulation method is used, which has a lower transmission efficiency but a lower complexity to reduce the system complexity.

[0119] In a possible embodiment, the method further includes: when the receiving end demodulates and decodes in error in the first target transport layer, the receiving end stores the decoding result of the successfully decoded transport layer in a buffer.

[0120] When the receiving end decodes the transport layer corresponding to the decoding result stored in the buffer, the receiving end calls the decoding result in the buffer.

[0121] It should be noted that during the demodulation and decoding process, if the first target transport layer makes an error, the result of the successfully decoded transport layer is stored in the buffer; when decoding the transport layer corresponding to the decoding result stored in the buffer during retransmission, the correctly decoded result is directly extracted from the buffer as the correct codeword of the corresponding transport layer.

[0122] Figure 5 This is a schematic diagram of the demodulation and decoding process of a receiving end provided by an embodiment of the present application. As Figure 5As shown, in this scheme, the receiving end of the multi-level coded modulation system adopts a multi-level series mode to perform demodulation and decoding. After demodulating the modulation symbol S once, it starts from the transmission layer with low signal-to-noise ratio (LDPC layer), calculates the LLR of this layer, and combines it with the initial transmission LLR to perform decoding operation to obtain the first layer codeword, which is marked in the constellation diagram; on this basis, re-encoding is performed to reconstruct the transmitted signal before modulation, and the transmission layer with the second lowest signal-to-noise ratio (BCH layer) is demodulated twice to decode the second layer LLR, which is combined and decoded accordingly to obtain the second layer codeword, which is marked in the constellation diagram; and so on to the case of N transmission layers.

[0123] like Figure 5 As shown, the specific steps in the three-layer coding system of this embodiment are: after the receiving end finds a decoding error, it sends a signal NACK to the sending end and puts the LLR of the initial transmission into the cache. The sending end retransmits the data packet. The receiving end demodulates the retransmitted data packet once and merges the result with the LLR of the initial transmission to form a codeword with a lower code rate. On this basis, the LDPC decoding operation is performed. If it is a correct codeword, it is marked in the constellation diagram and then continues to demodulate the next layer. The next layer is the BCH layer. The receiving end performs a second demodulation on the received codewords transmitted by the initial transmission and the retransmitted BCH layer, merges the two, and first performs LDPC decoding. On this basis, BCH decoding is performed to decode the correct BCH codeword. The receiving end checks whether the decoded codeword is correct. The correct codeword is marked in the constellation diagram as the second layer bit. Next, BCH re-encoding is performed, and then the initial and retransmitted NC layer codewords are demodulated three times at the same time. The two are combined and LDPC decoding is performed on them. Since this layer is not encoded during the initial transmission, the decoded codeword is the original codeword. Therefore, after the judgment is correct, the codeword is marked on the constellation diagram to obtain the third layer bit position. At this point, MLC demodulation is completed, and each layer can obtain additional gains brought by the reduction of the code rate, which improves the performance of MLCM retransmission. When the codewords of the second and third layers are wrong, the correct codewords of the previous layer are stored first, and then retransmitted. When retransmitting, the correct codewords do not need to be demodulated and decoded repeatedly, and are directly marked in the constellation diagram, which can save a certain amount of time and frequency resources.

[0124] Take 256QAM-404 as an example for simulation. The first 4 represents the bits of the LDPC layer, and the second 4 represents the bits of the NC layer. The simulation is as follows: Figure 6 As shown in the figure, curve 1 represents the performance curve of MCLM initial transmission, and curve 2 represents the performance curve of MCLM one retransmission. By comparing curve 1 and curve 2, it can be seen that when BER=1E-2, one retransmission brings about 3dB gain to the MLCM system, which verifies the application effect of this retransmission scheme in MLCM.

[0125] Figure 7A schematic structural diagram of a communication device provided by an embodiment of the present application. As Figure 7 shown, the communication device 700 provided in this embodiment is used to communicate with a receiving end in a multi-level coding and modulation system, and is used to implement the operations corresponding to the sending end in the foregoing method embodiments.

[0126] The communication device 700 may include: a transceiver module 701 and a processing module 702. The processing module 702 is used for data processing, and the transceiver module 701 can implement corresponding communication functions. The transceiver module 701 may also be referred to as a communication interface or a communication unit.

[0127] Optionally, the communication device 700 may further include a storage unit, which may be used to store instructions and / or data. The processing module 702 may read the instructions and / or data in the storage unit, so that the communication device 700 implements the steps implemented by the sending end in the foregoing method embodiments.

[0128] The transceiver module 701 is used to perform the operations related to receiving at the sending end in the foregoing method embodiments, and the processing module 702 is used to perform the operations related to processing at the sending end in the foregoing method embodiments.

[0129] Optionally, the transceiver module 701 may include a sending module and a receiving module. The sending module is used to perform the sending operation in the foregoing method embodiments. The receiving module is used to perform the receiving operation in the foregoing method embodiments.

[0130] It should be noted that the communication device 700 may include a sending module but not a receiving module. Or, the communication device 700 may include a receiving module but not a sending module. Specifically, it depends on whether the foregoing scheme executed by the communication device 700 includes a sending action and a receiving action.

[0131] As an example, the communication device 700 is used to perform the actions performed by the sending end in the foregoing Figure 1 illustrated embodiments.

[0132] The communication device 700 may include: a transceiver module 701 and a processing module 702.

[0133] The transceiver module 701 is used to obtain a first retransmission signal NACK from the receiving end.

[0134] The transceiver module 701 is further used to, based on the first NACK, perform J retransmissions on N transmission layers of the to-be-transmitted bit stream in an incremental redundancy manner, so that the receiving end can receive the first bit stream S corresponding to the first target transmission layer n (j - 1) and the second bit stream S n(j) Perform merging to obtain a third bitstream corresponding to the first target transport layer, and perform demodulation and decoding on the third bitstream; where N and J are both positive integers, and N≥2, J≥1; the first target transport layer is any one of the N transport layers; the second bitstream S n (j) includes a first bitstream S n (j - 1) and redundancy information, n is the serial number of the N transport layers, 1≤n≤N, j is the retransmission count of the nth transport layer, 0<j<J.

[0135] It should be understood that the execution of the above corresponding processes by each module has been described in detail in the above method embodiments. For the sake of brevity, it will not be repeated here.

[0136] The processing module 702 in the foregoing embodiments may be implemented by at least one processor or processor-related circuits. The transceiver module 701 may be implemented by a transceiver or transceiver-related circuits. The transceiver module 701 may also be referred to as a communication unit or communication interface. The storage unit may be implemented by at least one memory.

[0137] Figure 8 It is a schematic structural diagram of another communication device provided by an embodiment of the present application. As Figure 8 shown, the communication device 800 provided in this embodiment is used to communicate with the sending end in a multi-level coding and modulation system, and is used to implement the operations corresponding to the receiving end in the above method embodiments.

[0138] The communication device 800 may include: a transceiver module 801 and a processing module 802. The processing module 802 is used for data processing, and the transceiver module 801 may implement corresponding communication functions. The transceiver module 801 may also be referred to as a communication interface or communication unit.

[0139] Optionally, the communication device 800 may further include a storage unit, which may be used to store instructions and / or data. The processing module 802 may read the instructions and / or data in the storage unit so that the communication device 800 implements the steps implemented by the receiving end in the foregoing method embodiments.

[0140] The transceiver module 801 is used to perform the operations related to receiving at the receiving end in the foregoing method embodiments, and the processing module 802 is used to perform the operations related to processing at the receiving end in the foregoing method embodiments.

[0141] Optionally, the transceiver module 801 may include a sending module and a receiving module. The sending module is used to perform the sending operation in the above method embodiments. The receiving module is used to perform the receiving operation in the above method embodiments.

[0142] It should be noted that the communication device 800 may include a sending module but not a receiving module. Alternatively, the communication device 800 may include a receiving module but not a sending module. Specifically, it depends on whether the above-mentioned solution executed by the communication device 800 includes a sending action and a receiving action.

[0143] As an example, the communication device 800 is used to execute the actions performed by the receiving end in the embodiment described above. Figure 1 shown.

[0144] The communication device 800 may include: a transceiver module 801 and a processing module 802.

[0145] The transceiver module 801 is configured to send a first retransmission signal NACK to the sending end;

[0146] The processing module 802 is configured to, when the sending end performs J retransmissions on N transport layers of the bitstream to be transmitted in an incremental redundancy manner based on the first NACK, merge the first bitstream S n (j - 1) corresponding to the first target transport layer and the second bitstream S n (j) to obtain a third bitstream corresponding to the first target transport layer, and perform demodulation and decoding on the third bitstream; where N and J are both positive integers, and N ≥ 2, J ≥ 1; the first target transport layer is any one of the N transport layers; the second bitstream S n (j) includes the first bitstream S n (j - 1) and redundant information, n is the serial number of the N transport layers, 1 ≤ n ≤ N, j is the retransmission count of the nth transport layer, 0 < j < J.

[0147] It should be understood that the execution of the above corresponding processes by each module has been described in detail in the above method embodiments. For the sake of brevity, it will not be repeated here.

[0148] The processing module 802 in the foregoing embodiment may be implemented by at least one processor or processor-related circuit. The transceiver module 801 may be implemented by a transceiver or transceiver-related circuit. The transceiver module 801 may also be referred to as a communication unit or communication interface. The storage unit may be implemented by at least one memory.

[0149] Figure 9 It is a schematic structural diagram of an electronic device provided by an embodiment of the present application. As Figure 9 shown, the electronic device 900 provided in this embodiment includes: a memory 901 and a processor 902.

[0150] Among them, the memory 901 can be an independent physical unit, and can be connected to the processor 902 through the bus 903. The memory 901 and the processor 902 can also be integrated together and implemented through hardware, etc. The memory 901 is used to store program instructions, and the processor 902 calls the program instructions to execute the operations performed by the receiving end or the sending end in any of the above method embodiments.

[0151] Optionally, when part or all of the methods in the above embodiments are implemented by software, the electronic device 900 may also only include the processor 902. The memory 901 for storing the program is located outside the electronic device 900, and the processor 902 is connected to the memory through a circuit / wire for reading and executing the program stored in the memory. The processor 902 can be a central processing unit (CPU), a network processor (NP), or a combination of a CPU and an NP. The processor 902 may further include a hardware chip. The above hardware chip may be an application-specific integrated circuit (ASIC), a programmable logic device (PLD), or a combination thereof. The above PLD may be a complex programmable logic device (CPLD), a field-programmable gate array (FPGA), a generic array logic (GAL), or any combination thereof.

[0152] The memory 901 may include a volatile memory, such as a random-access memory (RAM); the memory may also include a non-volatile memory, such as a flash memory, a hard disk drive (HDD), or a solid-state drive (SSD); the memory may further include a combination of the above types of memories.

[0153] Exemplarily, the present application provides a chip, including: an interface circuit and a logic circuit, where the interface circuit is configured to receive a signal from another chip outside the chip and transmit it to the logic circuit, or send a signal from the logic circuit to another chip outside the chip, and the logic circuit is configured to perform the operations performed by the receiving end or the sending end in the above method embodiments.

[0154] Exemplarily, the present application provides a computer-readable storage medium, on which computer program instructions are stored, and the computer program instructions are run by a processor of an electronic device to cause the electronic device to perform the operations performed by the receiving end or the sending end in the above method embodiments.

[0155] Exemplarily, the present application provides a computer program product, which, when running on an electronic device, causes the electronic device to perform the operations performed by the receiving end or the sending end in the above method embodiments.

[0156] The above are only specific embodiments of the present application, enabling those skilled in the art to understand or implement the present application. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to these embodiments described herein, but rather will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A retransmission method for a multi - level coded modulation system, applied to a multi - level coded modulation system, characterized in that, The method includes: The sending end obtains a first retransmission signal NACK from the receiving end; The sending end performs J retransmissions on N transport layers of the bitstream to be transmitted respectively in an incremental redundancy manner based on the first NACK, so that the receiving end combines the first bitstream S n (j - 1) and the second bitstream S n (j) to obtain the third bitstream corresponding to the first target transport layer, and demodulates and decodes the third bitstream; where N and J are both positive integers, and N≥2, J≥1; the first target transport layer is any one of the N transport layers; the second bitstream S n (j) includes the first bitstream S n (j - 1) and redundant information, n is the serial number of the N transport layers, 1≤n≤N, j is the retransmission times of the nth transport layer, 0<j<J.

2. The method according to claim 1, wherein Before the sending end obtains the first retransmission signal NACK from the receiving end, the method further includes: The sending end performs an initial transmission on the N transport layers, and at least one of the N transport layers is encoded using a forward error correction code.

3. The method according to claim 2, wherein Before the sending end performs an initial transmission on the N transport layers, the method further includes: The sending end stratifies the bit stream to be transmitted based on the signal-to-noise ratio of the bit stream to be transmitted, and obtains the N transport layers corresponding to the bit stream to be transmitted. The N transport layers are a low-density parity-check (LDPC) layer, a Bose-Chaudhuri-Hocquenghem (BCH) error-correction coding layer, and a non-coded (NC) layer, respectively.

4. The method according to claim 3, characterized in that The sending end stratifies the bit stream to be transmitted based on the signal-to-noise ratio of the bit stream to be transmitted, and obtains the N transport layers corresponding to the bit stream to be transmitted, including: The sending end encapsulates the bit stream in the bit stream to be transmitted with a signal-to-noise ratio less than or equal to a first preset signal-to-noise ratio into an LDPC layer, and the bit stream in the LDPC layer is encoded using LDPC; The sending end encapsulates the bit stream in the bit stream to be transmitted with a signal-to-noise ratio greater than the first preset signal-to-noise ratio and less than or equal to a second preset signal-to-noise ratio into a BCH layer, and the bit stream in the BCH layer is encoded using BCH; The sending end encapsulates the bit stream in the bit stream to be transmitted with a signal-to-noise ratio greater than the second preset signal-to-noise ratio into an NC layer, and the bit stream in the NC layer is not encoded.

5. The method according to claim 1, wherein When the sender performs an initial transmission on the first target transport layer, it sends the first bitstream S to the receiver. n (j - 1). When the sender performs a single retransmission on the first target transport layer, it sends the second bitstream S to the receiver. n (j).

6. A retransmission method for a multi-level coded modulation system, applied to a multi-level coded modulation system, characterized in that, The method includes: The receiving end sends a first retransmission signal NACK to the sending end; When the receiving end is in the case where the sending end performs J retransmissions on N transport layers of the bitstream to be transmitted respectively in an incremental redundancy manner based on the first NACK, the first bitstream S corresponding to the first target transport layer n (j - 1) and the second bitstream S n (j) are combined to obtain the third bitstream corresponding to the first target transport layer, and the third bitstream is demodulated and decoded; where N and J are both positive integers, and N≥2, J≥1; the first target transport layer is any one of the N transport layers; the second bitstream S n (j) includes the first bitstream S n (j - 1) and redundant information, n is the serial number of the N transport layers, 1≤n≤N, j is the retransmission times of the nth transport layer, 0<j<J.

7. The method according to claim 6, characterized in that The receiving end merges the first bitstream S n (j - 1) corresponding to the first target transport layer and the second bitstream S n (j) to obtain the third bitstream corresponding to the first target transport layer, and demodulates and decodes the third bitstream, including: The receiving end performs quadrature amplitude modulation and demodulation (QAM demodulation) on the first bit stream S n (j - 1) to obtain the first log-likelihood ratio (LLR). The receiving end performs QAM demodulation on the second bitstream S n (j) to obtain a second LLR; The receiving end combines the first LLR and the second LLR to obtain a third LLR, and performs LDPC decoding on the third LLR.

8. The method according to claim 6, characterized in that, The method further includes: When at least one of the N transport layers has a decoding codeword error, the receiving end sends a second NACK to the sending end; the second NACK is used to indicate that all of the N transport layers are retransmitted, or the second NACK is used to indicate that a second target transport layer is retransmitted, and the second target transport layer is the transport layer with a decoding codeword error among the N transport layers.

9. The method according to claim 6, wherein The method further includes: When there is a demodulation and decoding error in the first target transport layer, the receiving end stores the decoding result of the transport layer that has been successfully decoded in a buffer; When the receiving end decodes the transport layer corresponding to the decoding result stored in the buffer, the receiving end calls the decoding result in the buffer.

10. A multi - level coded modulation system, characterized in that, The system includes: a sending unit and a receiving unit. The sending unit is used to implement the method implemented by the sending end in any one of claims 1 to 5, and the receiving unit is used to implement the method implemented by the receiving end in any one of claims 6 to 9.

Images