A method for using physical layer repeated transmission in 5G NR system

Abstract

The present invention relates to a method for adopting physical layer repeated transmission in a 5G NR system, which belongs to the field of mobile communication technology, and comprises: for a data block to be transmitted, different channel redundancy coding modes are adopted for encoding at a transmitting end, two independent data streams are formed through the same modulation mode, multiple layers of data are mapped to different logical ports through layer mapping, and the data are respectively sent out through different physical antenna ports; a receiving end receives wireless signals of different physical antenna ports from a wireless channel, and first uses a demodulation reference signal to complete timing synchronization, channel estimation and channel equalization processes for the received data; then obtains layer mapping data through a signal detection method; obtains two different modulated data streams by de-layer mapping the layer mapping data; obtains two different soft information through demodulation; and uses two different sets of log-likelihood values ​​to perform channel decoding on the two different soft information to obtain a transmission data block sent by the transmitting end.

Description

Technical Field

[0001] The present invention belongs to the technical field of mobile communications and relates to a method for adopting physical layer repeated transmission in a 5G NR system. Background Art

[0002] 3GPP has defined three major application scenarios for 5G: Enhanced Mobile Broadband (eMBB), Massive Machine Type Communication (mMTC), and Ultra Reliable & Low Latency Communication (URLLC).

[0003] Among them, Ultra-Reliable Low Latency Communication (URLLC) is a special use case of cellular communication, which includes a set of functions suitable for low-latency and high-reliability applications. Including mission-critical applications such as industrial automation, self-driving cars, smart grids, smart transportation / freight, and augmented / virtual reality or remote medical or industrial processes.

[0004] In the existing 3GPP 5G NR standard, high reliability is mainly achieved through repeated transmission, that is, PDCP repeated transmission (abbreviated as: PDCP duplication). The PDCP entity passes repeated PDCP PDUs to multiple RLC entities. The network can support up to four copies (COPY). The advantage is that it can be configured and used in certain existing architecture deployment scenarios (such as using CA or DC), and multiple wireless links are used for transmission to solve the reliability and latency requirements in communications. Although repeated transmission will increase wireless resource overhead and protocol complexity, in the process of multiple repeated transmissions, as long as one transmission is correct, it means that the data block has been successfully transmitted. This method has now been officially adopted by 3GPP and written into the specification. Figure 1 As shown in the figure, it is the repeated transmission mechanism of PDCP duplication in the current 5G NR system.

[0005] When the radio resource control layer (RRC) configures repeated transmission for a radio bearer, at least one secondary RLC entity is added to the radio bearer to handle repeated PDCP PDUs, such as Figure 1As shown, the logical channel corresponding to the primary RLC (RLC primary) entity is called the primary logical channel, and the logical channel corresponding to the secondary RLC entity is called the secondary logical channel. All RLC entities have the same RLC mode. Therefore, the PDCP layer submits the same PDCP PDU to different RLC entities multiple times to achieve multiple independent transmission paths to transmit the same data packet, improve the reliability of transmission and reduce delay, which is beneficial to URLLC services.

[0006] When repeated transmission is configured for a data radio bearer (DRB), the RRC layer (re)configures the PDCP repeated transmission state (activate or deactivate). After configuration, the PDCP repeated transmission state can be dynamically controlled by the media access control (MAC) control element (CE). And in dual link (DC), regardless of its source (MCG or SCG), the terminal can use MAC CE commands for control.

[0007] When repeated transmission is configured for a signaling radio bearer (SRB), the repeated state is always active and cannot be dynamically controlled.

[0008] When the DRB configuration of more than one secondary RLC entity has repeated transmission, RRC also sets the state of each entity (i.e., activated or deactivated). Subsequently, MAC CE can be used to dynamically control whether the repeated transmission of each secondary (secondary) RLC entity of the DRB configuration is activated or deactivated, i.e., which RLC entity is used for repeated transmission. However, the primary RLC entity cannot be deactivated.

[0009] When retransmission of a DRB is disabled, all secondary RLC entities associated with the DRB are disabled. When a secondary RLC entity is disabled, it is not reestablished, the HARQ buffer is not flushed, and the sending PDCP entity shall instruct the secondary RLC entity to discard all retransmission PDCP PDUs.

[0010] When DRB repetition is activated, the new generation radio access network (NG-RAN for short) ensures that there is at least one activated serving cell for each logical channel associated with the activated RLC entity of the DRB; and when the serving cell is deactivated and no serving cell is activated for the logical channel of the DRB, the NG-RAN ensures that the copy of the RLC entity associated with the logical channel will also be deactivated.

[0011] When repeated transmission is activated, the original PDCP PDU and the corresponding copy shall not be transmitted on the same carrier. The logical channels of the radio bearers configured with duplicates may belong to the same MAC entity (referred to as CA repeated transmission) or to different MAC entities (referred to as DC repeated transmission). When repeated transmission on more than two RLC entities is configured for a radio bearer, CA repeated transmission may also be configured together with DC repeated transmission in one or two MAC entities. In the CA repeated transmission mode, the MAC entity is restricted from using logical channel mapping to ensure that different logical channels of the radio bearers in the MAC entity are not sent on the same carrier. When CA repeated transmission is configured for an SRB, one of the logical channels associated with the SRB is mapped to the primary cell or the primary secondary cell (PCell or PSCell, referred to as SpCell).

[0012] When the RLC entity confirms that the PDCP PDU transmission is successful, the PDCP entity shall instruct other RLC entities to discard it. In addition, in the case of CA repeated transmission, when the RLC entity limited to the secondary cell (SCell) reaches the maximum number of retransmissions of the PDCP PDU, the UE notifies the base station (gNB) but does not trigger a radio link failure (RLF).

[0013] From the above description, in the current 5G NR PDCP retransmission function, it is required that the retransmission data blocks must use different wireless transmission paths to ensure transmission reliability, which can indeed increase the success rate of wireless link transmission. However, this method cannot achieve the effect of diversity transmission, that is, in the physical layer transmission process, whether DC or CA retransmission mode is used, they are independent of each other on the physical layer link, and there is no diversity transmission gain effect, which is much more difficult and complicated than single carrier in deployment. Summary of the invention

[0014] In view of this, an object of the present invention is to provide a diversity combining method for signal transmission over the air.

[0015] In order to achieve the above object, the present invention provides the following technical solutions:

[0016] A method for using physical layer repeated transmission in a 5G NR system, comprising:

[0017] For a data block to be transmitted, different channel redundancy coding methods are used for encoding at the transmitting end, and two independent data streams are formed through the same modulation method; the two data streams are mapped into multiple layers of data through layer mapping; the layer data is mapped to different logical ports, so that different logical port data are sent out through different physical antenna ports;

[0018] The receiving end receives wireless signals from different physical antenna ports on the wireless channel, and first uses the demodulation reference signal to complete the timing synchronization, channel estimation and channel equalization process of the received data; then obtains the layer mapping data through the signal detection method; obtains two different modulated data streams through the layer mapping data through the de-layer mapping process; obtains two different soft information through demodulation; uses two different sets of log-likelihood values ​​to perform channel decoding on the two different soft information to obtain the transmission data block sent by the transmitting end.

[0019] Furthermore, the data processing steps at the sending end are as follows:

[0020] Step A1: The physical layer receives the transport data block TransportBlock from the high-level protocol;

[0021] Step A2: The physical layer performs channel coding of different redundant versions on the transmission data block to form two coded data blocks CodedBlock1 and CodedBlock2;

[0022] Step A3: The physical layer performs modulation processing on the coded blocks CodedBlock1 and CodedBlock2 to form two blocks of modulation symbol data ModulatedBlock1 and ModulatedBlock2;

[0023] Step A4: performing layer mapping operation on ModulatedBlock1 and ModulatedBlock2 data to map into N layers of data LayerData1, LayerData2, ..., LayerDataN, where N≥2;

[0024] Step A5: Map the layer data to different logical antenna ports through precoding, and then map them together with the logical antenna port reference signal to the time-frequency resources of orthogonal frequency division multiplexing OFDM;

[0025] Step A6: The OFDM data of the logical antenna port is transmitted into the air through different physical antennas.

[0026] Further, in step A1, the physical layer receives a single transmission data block from the high-level protocol

[0027] TransportBlock uses dual codeword transmission. The two transmission parameters are the same. A cyclic checksum is added after the transport block TransportBlock. Depending on the size of the transport block, a 24-bit or 16-bit cyclic checksum is used to form the same transport block as TransportBlock1 and TransportBlock2.

[0028] Further, step A3 specifically includes the following steps:

[0029] A31: Perform the same rate matching, coded block concatenation and scrambling operations on CodedBlock1 and CodedBlock2 coded data blocks to generate ScrambleBlock1 and ScrambleBlock2 respectively;

[0030] A32: Perform orthogonal amplitude modulation on ScrambleBlock1 and ScrambleBlock2 to form ModulatedBlock1 and ModulatedBlock2 modulation symbol data of two codewords.

[0031] Further, in step A5, the N layers of data are mapped into N logical ports, a one-to-one mapping method is adopted, and then together with the logical port reference signal DMRS, a 5G NR time domain signal is obtained through a fast inverse Fourier transform IFFT.

[0032] Furthermore, in step A6, a logical antenna port is mapped to an independent physical antenna, and different physical antennas are located in different geographical locations.

[0033] Furthermore, the data processing steps at the receiving end are as follows:

[0034] Step B1: The receiving end receives OFDM data sent from the transmitting end from the air, and the number of receiving antennas of the receiving end is greater than the number of logical antenna ports used by the transmitting end;

[0035] Step B2: Perform OFDM symbol timing synchronization, channel estimation and channel equalization process through the demodulation reference signal in the OFDM symbol;

[0036] Step B3: Detect and process the channel to obtain the time-frequency resource corresponding to each logical port, and extract the time-frequency resource data corresponding to each logical port from each logical port;

[0037] Step B4: Perform logical port precoding decoding on the logical port time-frequency resource data to obtain layer data LayerData1, LayerData2, ..., LayerDataN;

[0038] Step B5: performing a de-layer mapping operation on the layer data to obtain two blocks of modulated data ModulatedBlock1 and ModulatedBlock2;

[0039] Step B6: demodulate the modulated data ModulatedBlock1 and ModulatedBlock2 to obtain soft information llrBlock1 and llrBlock2;

[0040] Step B7: Send the llrBlock1 and llrBlock2 soft information to the channel decoder for decoding to obtain the transport data block TransportBlock sent by the transmitter.

[0041] Further, step B6 specifically includes: descrambling ModulatedBlock1 and ModulatedBlock2 to obtain CodedBlock1 and CodedBlock2 data blocks, and then performing orthogonal amplitude demodulation on CodedBlock1 and CodedBlock2 to obtain log-likelihood values ​​llrBlock1 and llrBlock2 of the two data blocks.

[0042] Further, step B7 specifically includes: performing joint LDPC decoding on the soft information of llrBlock1 and llrBlock2 simultaneously to obtain a transport data block TransportBlock; performing cyclic verification on the TransportBlock, and if the cyclic verification is correct, submitting the correct transport data block TransportBlock to the high-level protocol stack.

[0043] Furthermore, in the channel decoding described in step B7, llrBlock1 is first used for decoding. If the decoding is correct, llrBlock2 is directly discarded. If llrBlock1 is decoded incorrectly, it is soft-merged with the received llrBlock2, and llrBlock1 is continued to be decoded, and finally the TransportBlock is decoded.

[0044] In mobile communication networks, there has always been a problem of how to improve communication reliability, especially in the application of URLLC scenarios in 5G NR systems. Currently, 3GPP has provided a solution for PDCP repeated transmission, that is, repeated transmission is used to improve the transmission accuracy. This method has two ways to perform repeated transmission. One is to use a multi-carrier (CA) mode, and repeated transmission blocks are repeatedly transmitted on different carriers. The other is to use a dual link (DC) mode, and repeated transmission blocks are repeatedly transmitted on different access technologies. However, the existing repeated transmission requires both the network and the terminal to support CA or DC, which is much more difficult and complicated to deploy than a single carrier.

[0045] Based on this, the beneficial effects of the present invention are:

[0046] First: The present invention proposes a method for repeated transmission at the physical layer, which can also be used in a single-carrier mobile communication system, reduces the requirements for equipment and spectrum resources, and does not require dual links or multiple carriers to implement.

[0047] Second: In mobile communication systems, as the operating frequency increases, in order to provide coverage effect and coverage performance, a large number of remote radio heads (RRHs) are used. The method of the present invention does not need to add more carriers to perform data block repetitive transmission, and increases RRHs to provide transmission gains from different directions.

[0048] Third: In the existing PDCP repeated transmission method, multiple repeated transmission combining gain cannot be obtained, but the method of the present invention can perform diversity combining processing on the data blocks repeatedly transmitted from different directions, which is equivalent to performing a retransmission at the same time at the physical layer, greatly improving the transmission accuracy.

[0049] Other advantages, objectives and features of the present invention will be described in the following description to some extent, and to some extent, will be obvious to those skilled in the art based on the following examination and study, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be realized and obtained through the following description. BRIEF DESCRIPTION OF THE DRAWINGS

[0050] In order to make the purpose, technical solutions and advantages of the present invention more clear, the present invention will be described in detail below in conjunction with the accompanying drawings, wherein:

[0051] Figure 1 Diagram of PDCP retransmission mechanism defined by 3GPP;

[0052] Figure 2 This is a flow chart of 5G NR base station transmission and terminal reception of the present invention;

[0053] Figure 3 This is a flow chart of sending PDSCH data by a base station according to an embodiment of the present invention;

[0054] Figure 4 This is a flow chart of a terminal receiving PDSCH data according to an embodiment of the present invention;

[0055] Figure 5 It is a mapping relationship diagram of PDSCH layer data, logical port and physical port;

[0056] Figure 6 This is a simulation diagram of the repeated transmission performance of the 5G NR physical layer. DETAILED DESCRIPTION

[0057] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the illustrations provided in the following embodiments only illustrate the basic concept of the present invention in a schematic manner, and the following embodiments and features in the embodiments can be combined with each other without conflict.

[0058] Among them, the drawings are only used for illustrative explanations, and they only represent schematic diagrams rather than actual pictures, and should not be understood as limitations on the present invention. In order to better illustrate the embodiments of the present invention, some parts of the drawings may be omitted, enlarged or reduced, and do not represent the size of actual products. For those skilled in the art, it is understandable that some well-known structures and their descriptions in the drawings may be omitted.

[0059] The same or similar numbers in the drawings of the embodiments of the present invention correspond to the same or similar parts; in the description of the present invention, it should be understood that if the terms "upper", "lower", "left", "right", "front", "rear", etc. indicate the orientation or position relationship, they are based on the orientation or position relationship shown in the drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation. Therefore, the terms describing the position relationship in the drawings are only used for illustrative purposes and cannot be understood as limiting the present invention. For ordinary technicians in this field, the specific meanings of the above terms can be understood according to specific circumstances.

[0060] In order to clearly illustrate the application of the present invention in an actual mobile communication system, the present invention provides an embodiment of using physical layer diversity repeated transmission, that is, in the existing fourth generation / fifth generation (4G / 5G) mobile network, the high-level protocol uses a single codeword (abbreviated as: one codeword) to send data blocks, also known as physical layer transmission blocks (abbreviated as: TransportBlock blocks). In the physical layer channel coding process, two different redundant coding methods are used to form dual codeword data through signal modulation. The layer mapping independently maps the dual codeword data to different layers, and the layer data is then mapped to different antenna ports, and finally sent out through different physical antennas. At the receiving end, channel timing synchronization, channel estimation and equalization are completed, and signal detection is performed on the received data. Two layers of data are obtained by de-layer mapping. Each layer of modulated data is demodulated separately to obtain soft information of the two layers of data, namely the log-likelihood value (abbreviated as: LLR). The two sets of received data LLRs are simultaneously sent to the channel decoder for decoding to obtain the transmission data block TransportBlock sent by the final sending end. Figure 2In this embodiment, if the processing is the same as that of the existing 3GPP, a reference protocol is directly given and no further detailed description is given in this embodiment.

[0061] In this embodiment, two processes are used: the 5G NR base station sends physical downlink shared channel (PDSCH) data and the terminal receives PDSCH data.

[0062] In this embodiment, the process of sending PDSCH data by the base station is as follows:

[0063] Step 1: The physical layer receives a single transport data block (abbreviated as TransportBlock) from the high-level protocol, adopts dual codeword transmission, and the two transmission parameters are the same. A cyclic check code is added after the transport block TransportBlock. Depending on the size of the transport block, a 24-bit or 16-bit cyclic check is adopted. For details, refer to the description in section 7.2.1 of 3GPPTS38.212. Using the method of the present invention, the physical layer will repeatedly transmit the TransportBlock data block to form the same transport blocks of TransportBlock1 and TransportBlock2. Figure 3 Step 1 in .

[0064] Step 2: The physical layer uses different redundancy versions to perform low-density parity check code (LDPC) channel coding on TransportBlock1 and TransportBlock2 to obtain two sets of channel coded data blocks CodedBlock1 and CodedBlock2. For details, refer to 3GPP TS38.212, sections 7.2.2, 7.2.3 and 7.2.4. According to the method of the present invention, the coding system bits of CodedBlock1 and CodedBlock2 are the same, and only the redundant bits are different. Figure 3 Step 2 in .

[0065] Step 3: Perform the same rate matching, code block concatenation and scrambling operations on CodedBlock1 and CodedBlock2, and finally generate ScrambleBlock1 and ScrambleBlock2 respectively. For rate matching and code block concatenation, refer to Sections 7.2.5 and 7.2.6 of 3GPP TS38.212; for scrambling operations, refer to Section 7.3.1.1 of 3GPP TS38.211. Figure 3 Step 3 in .

[0066] Step 4: Perform the same signal modulation on ScrambleBlock1 and ScrambleBlock2. In this embodiment, quadrature amplitude modulation (abbreviated as 16QAM) is used to form ModulatedBlock1 and ModulatedBlock2 modulation symbol data of two codewords. For details, refer to section 7.3.1.2 of 3GPP TS38.211. Figure 3 Step 4 in .

[0067] Step 5: Use layer mapping to map two codeword data into N (N≥2) layers of data, recorded as LayerData. In this embodiment, a 2-codeword mapping 6-layer method is used, that is, mapping into 6 layers of data. For details, refer to section 7.3.1.3 of 3GPP TS38.211. Figure 3 Step 5 of .

[0068] Step 6: Map the 6-layer LayerData data to different logical ports for transmission. In this embodiment, 6 logical ports are used for transmission. For details, refer to 3GPP TS38.211, sections 7.3.1.4, 7.3.1.5 and 7.3.1.6. Figure 3 Step 6 in .

[0069] Step 7: Different logical ports are mapped to different physical layer antenna ports for transmission into the air. In this embodiment, one logical antenna port is mapped to an independent physical antenna, and different physical antennas are located in different geographical locations. Figure 3 Step 7 of .

[0070] In this embodiment, the terminal receives PDSCH data and processes the following:

[0071] Step 1: The receiving end receives the air signal, and obtains 6-layer modulated data LayerData after automatic gain control (AGC) adjustment, timing synchronization, channel estimation and equalization, and signal detection. Figure 4 Step 1 in .

[0072] Step 2: In this embodiment, a 2-codeword mapping 6-layer method is adopted to perform a de-layer mapping operation on the received 6-layer LayerData to obtain channel modulated data ModulatedBlock1 and ModulatedBlock2. For details, refer to section 7.3.1.3 of 3GPP TS38.211. Figure 4 Step 2 in .

[0073] Step 3: Descramble ModulatedBlock1 and ModulatedBlock2 to obtain CodedBlock1 and CodedBlock2 data blocks, and then demodulate CodedBlock1 and CodedBlock2. In this embodiment, 16QAM demodulation is used to obtain the log-likelihood values ​​llrBlock1 and llrBlock2 of the two data blocks. For details, refer to section 7.3.1.2 of 3GPPTS38.211. Note: Scrambling is completed by bit operation at the transmitting end, but the descrambling process is completed by symbol operation at the receiving end. Figure 4 Step 3 in .

[0074] Step 4: Perform joint LDPC decoding on the soft information of llrBlock1 and llrBlock2 to obtain a transport data block TransportBlock. For details, refer to section 7.2.4 of 3GPP TS38.212. Figure 4 Step 4 in .

[0075] In channel decoding, llrBlock1 is first used for decoding. If the decoding is correct, llrBlock2 is directly discarded. If llrBlock1 is decoded incorrectly, it is soft-merged with the received llrBlock2 and llrBlock1 is decoded. Finally, the TransportBlock is decoded.

[0076] Step 5: Perform a cyclic check on the TransportBlock. If the cyclic check is correct, submit the correct transport data block TransportBlock to the high-level protocol stack. For details, refer to section 7.2.1 of 3GPP TS38.212. Figure 4 Step 5 of .

[0077] In this embodiment, the layer mapping, logical port mapping and physical port mapping are described as follows: Figure 5 As shown. In this embodiment, the transport block TransportBlock adopts a repeated transmission mode, and two scrambled data blocks ScrambleBlock1 and ScrambleBlock2 are obtained. Six layers of data are obtained through layer mapping, which are recorded as LayerData1, LayerData2, ..., LayerData6. In this embodiment, the six layers of data are mapped to six logical ports, and a one-to-one mapping method is adopted. Then, together with the logical port reference signal DMRS, a 5G NR time domain signal is obtained through a fast inverse Fourier transform (abbreviated as: IFFT), and finally sent to the air through a physical antenna.

[0078] In this embodiment, the 5G Toolbox provided by Matlab 2022A version is used for simulation verification. In the simulation verification, one code corresponds to 2 layers, and two codes correspond to 4 layers in total. The simulation parameters are shown in Table 1.

[0079] Table 1 Physical layer repeated transmission simulation parameter configuration table

[0080]

[0081] The 5G NR PDSCH link is used for simulation. The simulation results are as follows: Figure 6 As shown in Table 2. Among them, initialTransmissionErrRatio indicates the bit error rate of the TransportBlock transmission data block that is only sent once during the simulation process; phyDuplicatonErrRatio indicates the bit error rate when repeated transmission is enabled at the physical layer, and only the bit error rate of the repeated transmission block is counted; transmissionErrRatio indicates the bit error rate of two transmission blocks when repeated transmission is performed at the physical layer; phyCombineErrRatio indicates the bit error rate when repeated transmission is performed at the physical layer, and only the bit error rate after the transmission block and repeated transmission are combined is counted. As shown in Table 2.

[0082] Table 2 Bit error rate under various simulation conditions

[0083]

[0084] exist Figure 6 In order to facilitate analysis, the four simulation situations are compared and displayed in initiaAndCombineErrRatio. It can be clearly seen that phyCombine is about 3db to 4db higher than initialTransmission. This shows that the method of the present invention, while sacrificing wireless resources, adopts the physical layer retransmission transmission method, which can provide the accuracy rate of the transmission block that the high-level protocol stack needs to send.

[0085] Finally, it should be noted that the above embodiments are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the purpose and scope of the technical solution, which should be included in the scope of the claims of the present invention.

Claims

1. A method for repeated transmission of a physical layer in a 5G NR system, characterized in that: include: For a data block that needs to be transmitted, different channel redundancy coding methods are used to encode it at the sending end, and two independent data streams are formed through the same modulation method; Mapping the two data streams into multiple layers of data through layer mapping; mapping the layer data to different logical ports so that data from different logical ports are sent out through different physical antenna ports; The receiving end receives wireless signals from different physical antenna ports on the wireless channel, and first uses the demodulation reference signal to complete the timing synchronization, channel estimation and channel equalization process of the received data; then obtains the layer mapping data through the signal detection method; and obtains two different modulated data streams through the layer mapping process; Obtain two different soft information by demodulation; use two different sets of log-likelihood values ​​to perform channel decoding on the two different soft information to obtain a transmission data block sent by a transmitting end; The data processing steps at the sending end are as follows: Step A1: The physical layer receives a transport data block TransportBlock from a high-level protocol; the physical layer receives a single transport data block TransportBlock from a high-level protocol, adopts dual codeword transmission, and the two transmission parameters are the same. A cyclic checksum is added after the transport block TransportBlock. According to the size of the transport block, a 24-bit or 16-bit cyclic checksum is adopted to form the same transport block of TransportBlock1 and TransportBlock2; Step A2: The physical layer performs channel coding of different redundant versions on the transmission data block to form two coded data blocks CodedBlock1 and CodedBlock2; Step A3: The physical layer performs modulation processing on the coded blocks CodedBlock1 and CodedBlock2 to form two blocks of modulation symbol data ModulatedBlock1 and ModulatedBlock2; Step A4: performing layer mapping operation on ModulatedBlock1 and ModulatedBlock2 data to map into N layers of data LayerData1, LayerData2, ..., LayerDataN, where N≥2; Step A5: Map the layer data to different logical antenna ports through precoding, and then map them together with the logical antenna port reference signal to the time-frequency resources of orthogonal frequency division multiplexing OFDM; Step A6: The OFDM data of the logical antenna port is transmitted into the air through different physical antennas; The data processing steps at the receiving end are as follows: Step B1: The receiving end receives OFDM data sent from the transmitting end from the air, and the number of receiving antennas of the receiving end is greater than the number of logical antenna ports used by the transmitting end; Step B2: Perform OFDM symbol timing synchronization, channel estimation and channel equalization process through the demodulation reference signal in the OFDM symbol; Step B3: Detect and process the channel to obtain the time-frequency resource corresponding to each logical port, and extract the time-frequency resource data corresponding to each logical port from each logical port; Step B4: Perform logical port precoding decoding on the logical port time-frequency resource data to obtain layer data LayerData1, LayerData2, ..., LayerDataN; Step B5: performing a de-layer mapping operation on the layer data to obtain two blocks of modulated data ModulatedBlock1 and ModulatedBlock2; Step B6: demodulate the modulated data ModulatedBlock1 and ModulatedBlock2 to obtain soft information llrBlock1 and llrBlock2; Step B7: sending the llrBlock1 and llrBlock2 soft information to the channel decoding for decoding to obtain the transport data block TransportBlock sent by the transmitting end; Step B7 specifically includes: performing joint LDPC decoding on the llrBlock1 and llrBlock2 soft information at the same time to obtain a transport data block TransportBlock; The TransportBlock is cyclically checked. If the cyclic check is correct, the correct transport data block TransportBlock is submitted to the high-level protocol stack.

2. The method for repeated transmission of the physical layer in the 5G NR system according to claim 1, characterized in that: Step A3 specifically includes the following steps: A31: Perform the same rate matching, coded block concatenation and scrambling operations on CodedBlock1 and CodedBlock2 coded data blocks to generate ScrambleBlock1 and ScrambleBlock2 respectively; A32: Perform orthogonal amplitude modulation on ScrambleBlock1 and ScrambleBlock2 to form ModulatedBlock1 and ModulatedBlock2 modulation symbol data of two codewords.

3. The method for repeated transmission of the physical layer in the 5G NR system according to claim 1, characterized in that: In step A5, the N-layer data is mapped into N logical ports, a one-to-one mapping method is adopted, and then together with the logical port reference signal DMRS, a fast inverse Fourier transform IFFT is performed to obtain the 5G NR time domain signal.

4. The method for repeated transmission of the physical layer in the 5G NR system according to claim 1, characterized in that: In step A6, a logical antenna port is mapped to an independent physical antenna, and different physical antennas are located in different geographical locations.

5. The method for repeated transmission of the physical layer in the 5G NR system according to claim 1, characterized in that: Step B6 specifically includes: descrambling ModulatedBlock1 and ModulatedBlock2 to obtain CodedBlock1 and CodedBlock2 data blocks, and then performing orthogonal amplitude demodulation on CodedBlock1 and CodedBlock2 to obtain log-likelihood values ​​llrBlock1 and llrBlock2 of the two data blocks.

6. The method for repeated transmission of the physical layer in the 5G NR system according to claim 1, characterized in that: In the channel decoding described in step B7, llrBlock1 is first used for decoding. If the decoding is correct, llrBlock2 is directly discarded; If llrBlock1 is decoded incorrectly, it is soft-merged with the received llrBlock2, and llrBlock1 is decoded again, and finally the TransportBlock is decoded.

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