Method, device, storage medium and program product for data retransmission

Abstract

Embodiments of the present application provide a data retransmission method, device, storage medium and program product, relating to the technical field of wireless communication. The method comprises: when the number of retransmissions of a target transport block at a first MAC layer reaches a first retransmission threshold, a first communication device generates a status report of a target data unit corresponding to the target transport block to be retransmitted and sends the status report to a second communication device. The second communication device retransmits the target data unit after receiving the status report. Therefore, by generating the status report of the target data unit corresponding to the target transport block to be retransmitted when the number of retransmissions of the target transport block at the first MAC layer reaches the first retransmission threshold, the second communication device can be notified to retransmit the target data unit without waiting for the reassembly timer of the first communication device to expire, thereby shortening the waiting time for sending the status report of each target data unit that needs to be retransmitted by the first communication device, and improving the real-time performance of data retransmission.

Description

Technical Field

[0001] This application relates to, but is not limited to, the field of wireless communication technology, and in particular to a method, apparatus, storage medium, and program product for data retransmission. Background Technology

[0002] In the field of wireless communication technology, Ultra-Reliable Low-Latency Communications (URLLC), which balances low latency and high reliability, has become a crucial evolutionary direction, especially in applications such as Extended Reality (XR) and Programmable Logic Controllers (PLCs). Currently, to provide low-latency transmission under high reliability conditions, Radio Link Control (RLC) retransmission mechanisms are commonly used. However, RLC retransmission mechanisms typically require the transmitter to receive a status report from the receiver's RLC layer before triggering the transmitter to retransmit the corresponding unreceived messages at the RLC layer. The condition for the receiver to report a status report to the transmitter is the expiration of the T-Reassembly timer set by the RLC layer. At this point, the retransmission at the RLC layer is limited by the duration set by the T-Reassembly timer; therefore, the real-time performance of data retransmission in related technologies is insufficient. Summary of the Invention

[0003] The following is an overview of the subject matter described in detail herein. This overview is not intended to limit the scope of the claims.

[0004] This application provides a method, apparatus, storage medium, and program product for data retransmission, which can improve the real-time performance of data retransmission.

[0005] In a first aspect, a data retransmission method according to an embodiment of this application is applied to a first communication device, the first communication device including a first media access control (MAC) layer, the method including: when the number of retransmissions of a target transport block in the first MAC layer reaches a preset first retransmission threshold, generating a status report of the target data unit to be retransmitted corresponding to the target transport block; and sending the status report to a second communication device.

[0006] Secondly, according to an embodiment of this application, a data retransmission method is provided and applied to a second communication device. The method includes: receiving a status report sent by a first communication device; wherein the status report is generated by the first communication device based on the target data unit to be retransmitted corresponding to the target transmission block when it is determined that the number of retransmissions of the target transmission block at the first MAC layer has reached a preset first retransmission threshold; and retransmitting the target data unit to the first communication device according to the status report.

[0007] Thirdly, according to the embodiments of this application, the communication device includes a memory and a processor; the memory is used to store a computer program; the processor is used to execute the computer program and, when executing the computer program, implement the data retransmission method as described in any of the first aspects or the data retransmission method as described in any of the second aspects.

[0008] Fourthly, the computer-readable storage medium provided according to the embodiments of this application stores computer-executable instructions, which, when executed by a processor, cause the processor to implement the data retransmission method as described in any of the first aspects and / or the data retransmission method as described in any of the second aspects.

[0009] Fifthly, the computer program product provided according to the embodiments of this application includes a computer program or computer instructions, the computer program or computer instructions being stored in a computer-readable storage medium, a processor of a communication device reading the computer program or computer instructions from the computer-readable storage medium, and the processor executing the computer program or computer instructions to cause the communication device to perform the data retransmission method as described in any of the first aspects and / or the data retransmission method as described in any of the second aspects.

[0010] According to the above embodiments of this application, at least the following beneficial effects are achieved: when it is determined that the number of retransmissions of the target transmission block in the first MAC layer reaches the first retransmission threshold, it indicates that the second communication device will not send the same target transmission block again in the second MAC layer before receiving a request for retransmission from the first communication device. By generating a status report of the target data unit to be retransmitted corresponding to the target transmission block when the number of retransmissions of the target transmission block in the first MAC layer reaches the first retransmission threshold, it is not necessary to wait for the reassembly timer of the first communication device to expire before notifying the second communication device to retransmit the target data unit. At this time, the retransmission of the target data unit does not need to strongly depend on the duration set by the reassembly timer, thereby shortening the waiting time for the first communication device to send the status report for each target data unit that needs to be retransmitted as much as possible while taking into account the reliability of data transmission, and improving the real-time performance of data retransmission. Attached Figure Description

[0011] Figure 1A schematic diagram of the communication system provided in this application; Figure 2 This is a flowchart illustrating the data retransmission method applied to a first communication device provided in this application; Figure 3 This is a schematic diagram of an embodiment of the data retransmission method provided in this application in the downlink direction; Figure 4 This is a schematic diagram of the typical symbol structure of URLLC in the data retransmission method provided in this application; Figure 5 This is a schematic diagram of another embodiment of the data retransmission method provided in this application in the downlink direction; Figure 6 This is a schematic diagram of an embodiment of the data retransmission method provided in this application in the uplink direction; Figure 7 This is a schematic diagram of an embodiment of the data retransmission method provided in this application, where RLC and MAC are mapped in a one-to-many scenario; Figure 8 This is a flowchart illustrating the data retransmission method for a second communication device provided in this application; Figure 9 A schematic diagram of the system composition of an embodiment of the communication device provided in this application. Detailed Implementation

[0012] To make the objectives, technical solutions, and advantages of this application clearer, the following detailed description is provided in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0013] It should be noted that although functional modules are divided in the device schematic diagram and a logical order is shown in the flowchart, in some cases, the steps shown or described may be performed in a different order than the module division in the device or the order in the flowchart. The terms "first," "second," etc., in the specification, claims, and the aforementioned drawings are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence.

[0014] The flowcharts shown in the accompanying drawings are merely illustrative and do not necessarily include all content and operations / steps, nor do they necessarily have to be performed in the described order. For example, some operations / steps can be broken down, while others can be combined or partially combined; therefore, the actual execution order may change depending on the specific circumstances.

[0015] The following is an explanation of the terms used in the embodiments of this application: AM, or Acknowledged Mode, indicates the confirmation mode.

[0016] Retransmission, or TB re-transmission, refers to the retransmission of a TB block.

[0017] PDU, or Protocol Data Unit, refers to the data unit transmitted between different layers of a communication protocol.

[0018] TD: Transport Block, used to describe data blocks transmitted over the transport channel. TB is the basic unit of transmission at the MAC layer.

[0019] With the deepening integration of B5G and 6G air-space-ground networks, URLLC, which balances low latency and high reliability, has become a crucial evolution direction, especially for applications such as XR and PLC, and has become one of the key factors enabling industrial field networks. However, currently, low latency under high reliability conditions still relies on the RLC retransmission mechanism. This mechanism requires the transmitter to receive a STATUS report from the receiver's RLC layer before the transmitter can retransmit the corresponding unreceived packets at the corresponding RLC layer. In other words, the transmitter learns the receiver's RLC layer reception status through the STATUS report sent by the peer (i.e., the receiver). When the receiver's reassembly timer expires, the receiver will no longer attempt to receive the lost RLC report and will trigger the STATUS reporting process, requiring the transmitter to retransmit the RLCPDU data packets that the receiver did not receive. For example, after the transmitter sends an RLC PDU (such as PDU1) to the receiver, it needs to wait for the receiver to reply to the transmitter whether its RLC layer successfully received PDU1. The receiver informs the receiving end whether it has successfully received PDU1 by replying with a STATUS report. If the receiver replies that PDU1 was not received, it indicates the sequence number (SN) of the NACK packet (i.e., the SN of PDU1) in the reply STATUS report. The transmitter then determines, based on the STATUS report, that the RLC PDU with that SN needs to be retransmitted. However, since there is no interaction between the receiver's RLC layer and MAC layer, if the retransmission count of the MAC layer has reached its maximum before the reassembly timer expires, the RLC layer still needs to wait for the reassembly timer to expire. However, the time from when the MAC layer exhausts its maximum retransmission count and determines that the last retransmitted TB block failed to be received, to when the reassembly timer expires, is a meaningless wait, resulting in insufficient timeliness of retransmission. Based on this, embodiments of this application provide a data retransmission method, apparatus, storage medium, and program product that can improve the real-time performance of data retransmission.

[0020] Reference Figure 1As shown in the illustration, this application provides a communication system including a first communication device and a second communication device. The first communication device includes a first MAC layer and a first RLC layer, and the second communication device includes a second MAC layer and a second RLC layer. When the number of retransmissions of a target transmission block at the first MAC layer reaches a preset first retransmission threshold, the first RLC layer generates a status report of the target data unit to be retransmitted corresponding to the target transmission block. The first MAC layer sends the status report to the second RLC layer. After receiving the status report, the second RLC layer sends the target transmission unit to the second MAC layer, which then encapsulates the target transmission unit into a transmission block and retransmits it to the first MAC layer.

[0021] Therefore, when the number of retransmissions of the target transport block at the first MAC layer reaches the first retransmission threshold, it indicates that the second communication device will not send the same target transport block again through the second MAC layer before receiving a retransmission request from the first communication device. At this time, by generating a status report of the target data unit to be retransmitted corresponding to the target transport block when the number of retransmissions of the target transport block at the first MAC layer reaches the first retransmission threshold, it is not necessary to wait for the reassembly timer of the first communication device to expire before notifying the second communication device to retransmit the target data unit. The retransmission of the target data unit does not have to rely heavily on the duration set by the reassembly timer. Thus, while taking into account the reliability of data transmission, the waiting time for the first communication device to send the status report for each target data unit that needs to be retransmitted can be shortened as much as possible, thereby improving the real-time performance of data retransmission.

[0022] The first MAC layer and the second MAC layer are the MAC layers of their respective devices, and the first RLC layer and the second RLC layer are the RLC layers of their respective devices. The data unit is the basic transmission unit of the RLC layer, and the transport block is the basic transmission unit of the MAC layer.

[0023] The target transport block is the transport block sent from the second MAC layer to the first MAC layer. The target data unit is the data unit that needs to be retransmitted by the second RLC layer, and is the data unit carried in the target transport block.

[0024] This application does not restrict how to determine whether the number of retransmissions of the same target transport block in the first MAC layer has reached the first retransmission threshold, nor does it restrict the origin of the first retransmission threshold. The first retransmission threshold can be configured directly in the second MAC layer by the second communication device, or it can be configured synchronously by the second communication device after the first communication device informs the second communication device.

[0025] Reference Figure 1As shown, the first communication device can be the receiving end of the second communication device. In some embodiments, when the first communication device is the sending end of the second communication device and the second communication device is the receiving end of the first communication device, the second communication device can also send a status report by referring to the steps of the first communication device described above, and the first communication device can also perform corresponding processing based on the received status report by referring to the steps of the second communication device described above, thereby improving the timeliness of retransmission in both the first and second communication devices in the transmission and reception directions. In other embodiments, the interaction between the first and second communication devices described above can also be applied only to the processing when the first communication device is the receiving end and the second communication device is the sending end. When the first communication device is the sending end and the second communication device is the receiving end, retransmission in this direction can adopt other methods, thereby maximizing the data retransmission latency. In this regard, the embodiments of this application do not impose limitations, and those skilled in the art can selectively set according to actual needs.

[0026] In some embodiments, the first communication device is a terminal device (UE), and the second communication device is a base station device. In other embodiments, the first and second communication devices may also be other devices. For example, if the retransmission mechanism involves both MAC layer retransmission and the data retransmission of the layer above the MAC layer (such as the RLC layer in the embodiments of this application), and the data retransmission above the MAC layer depends on the state interaction of the corresponding layers between the transmitting and receiving ends, then the above embodiments of this application can also be applied. Those skilled in the art can selectively configure this according to the actual situation.

[0027] Reference Figure 2 As shown, according to the data retransmission method applied to a first communication device according to this application, the first communication device includes a first Media Access Control (MAC) layer, and the method includes: Step S110: When the number of retransmissions of the target transmission block in the first MAC layer reaches the preset first retransmission threshold, generate a status report of the target data unit to be retransmitted corresponding to the target transmission block. Step S120: Send the status report to the second communication device.

[0028] Therefore, when the number of retransmissions of the target transport block at the first MAC layer reaches the first retransmission threshold, it indicates that the second communication device will not send the same target transport block again through the second MAC layer before receiving a retransmission request from the first communication device. At this time, by generating a status report of the target data unit to be retransmitted corresponding to the target transport block when the number of retransmissions of the target transport block at the first MAC layer reaches the first retransmission threshold, it is not necessary to wait for the reassembly timer of the first communication device to expire before notifying the second communication device to retransmit the target data unit. The retransmission of the target data unit does not have to rely heavily on the duration set by the reassembly timer. Thus, while taking into account the reliability of data transmission, the waiting time for the first communication device to send the status report for each target data unit that needs to be retransmitted can be shortened as much as possible, thereby improving the real-time performance of data retransmission.

[0029] The target transport block is the transport block sent from the second MAC layer of the second communication device to the first MAC layer.

[0030] The retransmission count is the number of times the same target transport block is repeatedly sent to the first MAC layer when the second MAC layer initiates a retransmission of the target transport block. This application embodiment does not limit how the retransmission count of the target transport block is determined in step S110 at the first MAC layer. It can be determined by the second MAC layer of the second communication device and then sent back to the first communication device, or it can be determined by the first MAC layer itself. Those skilled in the art can selectively set this according to the actual situation.

[0031] The first retransmission threshold represents the maximum number of times the same target transport block will be repeatedly sent to the first MAC layer when the second MAC layer initiates a retransmission of the target transport block. This application does not restrict how the first retransmission threshold is set. For example, it can be set directly at the second communication device, or the retransmission threshold can be set by the interaction between the first and second communication devices, with the second communication device setting the specific value of the first retransmission threshold to the first communication device.

[0032] The embodiments of this application do not limit the data units carried in the target transport block. For example, in some embodiments, a target transport block may carry one data unit, while in other embodiments, a target transport block may carry multiple data units.

[0033] A status report is used to indicate information about the target data unit to be retransmitted, enabling the second communication device to determine the data unit that needs to be retransmitted based on the status report. There can be a one-to-one correspondence between the status report and the target data unit.

[0034] Understandably, prior to step S110, the method also includes: Receive retransmission instruction signaling from the second communication device; When the retransmission indication signaling indicates that the target transmission block has completed the last retransmission, it is determined that the number of retransmissions has reached the first retransmission threshold.

[0035] This application does not limit the format of the retransmission indication signaling encapsulated in the second communication device, nor does it limit the channel carrying the retransmission indication signaling. Those skilled in the art can selectively configure it according to actual needs. For example, after the second MAC layer of the second communication terminal completes the last transmission of transmission block 1, it sends the retransmission indication signaling of transmission block 1 to the first MAC layer to indicate that transmission block 1 has completed the last retransmission. The retransmission indication signaling can be transmitted through the PDCCH channel.

[0036] This application does not limit the content carried in the retransmission indication signaling. In some embodiments, the retransmission indication signaling may carry the identification information of the target transport block, such as ID, etc.

[0037] For example, taking the first communication device as the terminal device and the second communication device as the base station device, and the target transport block as the downlink transport block, refer to... Figure 3 As shown, the specific steps for Example 1 are as follows: ① Data unit PDUn-2 starts transmission and reception is normal, such as Figure 3 As shown, the second RLC layer begins transmitting data unit PDUn-2 with sequence number n-2. The second MAC layer encapsulates PDUn-2 from the second RLC layer and adds a MAC layer header to obtain the corresponding target transport block. The target transport block corresponding to PDUn-2 is transmitted to the first MAC layer via the wireless air interface. The first MAC layer receives it correctly, removes the MAC header from the message, and delivers this n-2 PDU to the first RLC layer.

[0038] ② Data unit PDUn-1 initiates transmission and determines that reception has failed, such as Figure 3 As shown, the second RLC layer continues to transmit data unit PDUn-1 with sequence number n-1, as follows. Figure 3 As shown, if the target transmission corresponding to PDUn-1 fails to be received correctly at the first MAC layer (e.g., not received or parsing fails), the second MAC layer continues to send the target transmission block corresponding to PDUn-1 to the first MAC layer. When the number of times the target transmission block corresponding to PDUn-1 is transmitted on the transmission link between the second MAC layer and the first MAC layer reaches the maximum number of retransmissions and still fails to be received, the second MAC layer informs the first RLC layer through retransmission indication signaling, indicating that the second MAC layer of the second communication device has performed the last TB block retransmission for PDUn-1, and there will be no more HARQ retransmissions for this TB block by the second MAC layer.

[0039] In some embodiments, the retransmission indication signaling can employ DCI signaling, which is downlink physical layer signaling carried on the PDCCH channel. The MCS (Modulation Code Format) design, downlink BLER (Block Error Rate), and channel resource aggregation design of this channel can fully guarantee transmission reliability. The PDCCH channel is at least an order of magnitude more reliable than the PDSCH channel carrying downlink RLC data (i.e., PDUs in this embodiment) for a single transmission. For example, if the BLER of the traffic channel (i.e., the PDSCH channel) is 1 / 1000, then the BLER of the PDCCH is at least 1 / 10000. The PDCCH and PDSCH channels can physically meet the different transmission requirements of two major channel categories. Taking 7 symbols as an example, the typical symbol structure of URLLC is as follows: Figure 4 As shown, the horizontal lines represent OFDM symbols, and the vertical lines represent subcarriers. The PDCCH occupies two symbols, the DM-RS (DeModulation Reference Signal) is used for data demodulation, and occupies one symbol. The remaining symbols can be used for data transmission, occupying four symbols.

[0040] ③ The second MAC layer sends a retransmission indication signaling to the first MAC layer, such as... Figure 3 As shown, after receiving the retransmission instruction sent by the second MAC layer, the first MAC layer immediately informs the first RLC layer.

[0041] ④ The second RLC layer sends a status report to the first RLC layer to indicate that PDUn-1 needs to be retransmitted. At this time, if... Figure 3 As shown, even if the T-Reassembly timer of the first RLC layer expires before it does, a STATUSreport will be sent to the second RLC layer immediately, requesting the second RLC layer to retransmit the data packet with RLC SN sequence number n-1 (i.e., PDUn-1).

[0042] like Figure 3 As shown, when the second RLC layer receives the STATUS report from the first communication device, it immediately begins retransmission of PDU n-1.

[0043] At this time, as Figure 3 In the example shown, since the T-Reassembly timer is started when the first RLC layer determines that PDU n-1 has failed to be received normally, when the duration of the T-Reassembly timer is t1, in the retransmission implementation of this application, the status report can be sent as soon as the retransmission indication signaling is received at the first RLC layer. Compared with the existing schemes that require waiting for the T-Reassembly timer to time out before sending, Figure 3As shown, the embodiments of this application can reduce latency. Assuming the duration of the T-Reassembly timer is t1, the reduction in latency is as follows: Figure 3 The figure t2 is shown.

[0044] Understandably, the retransmission indication signaling is either Downlink Control Information (DCI) signaling or Media Access Control Unit (MACCE) signaling.

[0045] MAC CE signaling is a method used in LTE systems for exchanging MAC layer control information between the UE and the network. MAC CE signaling is exchanged through the MAC layer and carried on the PDSCH.

[0046] DCI signaling is a control command dynamically scheduled by the physical layer in 5G networks. DCI interacts directly through the physical layer and is carried on PDCCH or PUCCH.

[0047] In some embodiments, the retransmission indication signaling is encapsulated as DCI signaling for transmission. In other embodiments, the retransmission indication signaling is encapsulated as MAC CE format signaling for transmission. In still other embodiments, either DCI signaling or MAC CE signaling can be dynamically selected for retransmission indication signaling transmission based on network resource status.

[0048] Understandably, the first communication device also includes a first radio link control protocol (RLC) layer, and the method further includes: Based on the cumulative number of retransmissions of the transport block control information signaling in the first MAC layer, it is determined whether the number of retransmissions has reached the first retransmission threshold; wherein, the transport block control information signaling is the DCI signaling transmitted in pairs with the target transport block.

[0049] The cumulative retransmission count represents the total number of times the first MAC layer sends the same target transport block to the second MAC layer.

[0050] Transport block control signaling is transmitted via PDCCH, which has higher reliability than the target transport block. Therefore, the cumulative number of retransmissions of the target transport block can be determined based on the transport control information signaling.

[0051] This application does not impose any restrictions on how the cumulative number of retransmissions is determined. Those skilled in the art can selectively set it according to the actual scenario. For example, in some embodiments, if the first communication device is a UE, the number of block control information signaling messages received for the same target transport block can be used to make the statistics.

[0052] The first retransmission threshold can be set dynamically or fixedly based on communication quality; this application does not impose any restrictions on this.

[0053] For example, the first communication device is a terminal device (UE), and the second communication device is a base station device. Taking the target transport block as an example, which is a downlink transport block, refer to... Figure 5 As shown, the specific steps for Example 2 are as follows: ① The base station equipment sends the second retransmission threshold of the second MAC layer to the first MAC layer. The second retransmission threshold represents the maximum number of retransmissions configured in the second MAC layer for the same transport block, such as... Figure 5 As shown, during the RLC layer connection between the base station device and the UE, the base station device configures the maximum number of downlink HARQ retransmissions Nmax to the UE through RRC reconfiguration in the second RRC layer, which is to send the second retransmission threshold to the UE's first MAC layer.

[0054] ② Data unit PDUn-2 starts transmission and reception is normal, such as Figure 5 As shown, the base station equipment transmits data unit PDUn-2 with sequence number n-2 from the second RLC layer to the second MAC layer, and then sends the transport block corresponding to PDUn-2 to the UE's first MAC layer through the second MAC layer. Figure 5 As shown, the UE's first RLC layer received the data correctly.

[0055] ③ Data unit PDUn-1 initiates transmission and determines that reception at the first RLC layer has failed, such as Figure 5 As shown, the second RLC layer of the base station device continues to transmit n-1 data units PDUn-1. The UE detects in the first MAC layer that PDUn-1 has been sent through the second MAC layer Nmax times and the first MAC layer still fails to receive it. That is, the number of retransmissions of the transmission block corresponding to PDUn-1 in the first MAC layer has reached the first retransmission threshold Nmax and still fails to receive it. At this time, it is determined that the first RLC layer has failed for PDUn-1.

[0056] ④ The first MAC layer sends the final data indication to the first RLC layer, such as Figure 5 As shown, the first MAC layer immediately informs the UE's first RLC layer of the last data indication so that the first RLC layer can determine that this is the last TB block transmission for n-1 PDUs.

[0057] ⑤ The first RLC layer sends a status report to the second RLC layer, such as Figure 5 As shown, assuming the duration of the T-Reassembly timer is t1, then as follows: Figure 5As shown, even if the T-Reassembly timer in the UE's first RLC layer has not expired, it will immediately send an RLC STATUS report to the base station's second RLC layer, requesting the base station's second RLC layer to immediately initiate retransmission for PDU n-1. The base station receives the RLC STATUS report from the UE. The base station's second RLC layer then initiates retransmission for PDU n-1.

[0058] At this time, refer to Figure 5 As shown, after executing ①~⑤, the T-Reassembly timer is started when the first RLC layer determines that PDUn-1 has failed to receive correctly (in some embodiments, such as...). Figure 5 As shown, the T-Reassembly timer corresponding to PDUn-1 can be started at the moment after the next data unit of PDUn-1 is received and it is determined that PDUn-1 has not yet been received. Therefore, as... Figure 5 As shown, the latency benefit can be obtained by referring to Example 2 of the embodiments of this application, wherein the reduction in latency is the time between sending the status report and the T-Reassembly timeout, that is... Figure 5 The figure t2 is shown.

[0059] In some embodiments, the identification logic for the maximum number of retransmissions by the base station device in Example 2 above is as follows: The UE can identify the retransmission of the TB corresponding to PDUn-1 by using the HARQ ID and NDI carried in the DCI. Here, NDI of 0 indicates retransmission. When the number of consecutive times that the NDI of the DCI corresponding to the TB of PDUn-1 is 0 has accumulated to Nmax, it means that the maximum number of retransmissions has been reached.

[0060] Understandably, the target transport block carries at least one data unit, and a status report for the target data unit to be retransmitted corresponding to the target transport block is generated, including: The reception status of each data unit is determined through the first RLC layer; Based on each reception status, determine the target data unit from at least one data unit; Generate a status report corresponding to the target data unit.

[0061] In some embodiments, there is a one-to-one correspondence between a status report and a target data unit.

[0062] By determining the reception status for each data unit separately, retransmission control can be performed on a unit-by-unit basis when each transport block can carry multiple data units. This ensures transmission quality while minimizing the number of transmissions.

[0063] In some embodiments, when multiple RLC entities are mapped to the MAC layer, one TB block in the MAC layer will correspond to multiple RLC messages. In this case, one TB will correspond to messages from multiple RLC AM entities; that is, an erroneous TB will correspond to RLC PDU messages with different sequence numbers from multiple RLC AM entities. At this time, there is a one-to-many mapping relationship between TBs and data units. For example, assuming the second communication device (e.g., a base station) has n RLC transmitting entities, the corresponding first communication device (e.g., a UE) must have n corresponding RLC receiving entities. Taking data block TB1 as an example, assuming it carries data packet PDUn1-2 with sequence number n1-2 in the second RLC1 entity and data packet PDUnn-1 with sequence number nn-1 in the second RLC2 entity, when TB1 transmits and receives normally at the MAC layer, the first MAC layer of the first communication device (such as UE) can deliver data packets PDUnn-1 and PDUn1-2 to the first RLC2 entity and the first RLC1 entity respectively. Here, the first RLC2 entity is the RLC receiving entity corresponding to the second RLC2 entity, and the first RLC1 entity is the RLC receiving entity corresponding to the second RLC1 entity. Similarly, assuming that the second MAC layer data block TB2 carries data packets with sequence number n1-1 from the second RLC1 entity and nn-2 from the first RLC2 entity (i.e., PDUn1-1 and PDUnn-2), if the transmission of TB2 at the MAC layer fails to be received normally (e.g., the first MAC layer fails to parse it or does not receive it), the UE's first MAC layer cannot send the data packet PDUn1-1 with sequence number nn-2 from the first RLC1 entity and / or the data packet nn-2 with sequence number nn-2 from the first RLC2 entity. When the retransmission of TB2 reaches the maximum number of times, the UE's first MAC layer notifies the first RLC1 and first RLC2 entities that they need to immediately report the status reports of PDUnn-2 and / or PDUn1-1 to the corresponding RLC entities in the base station equipment. After receiving the status reports of PDUnn-2 and PDUn1-1, the second RLC1 and second RLC2 entities of the base station equipment can immediately retransmit the erroneous packets (i.e., PDUnn-2 and PDUn1-1).

[0064] For example, in combination Figure 7 Another embodiment of this application is described, in which the base station device is the second communication device and the UE is the first communication device. The specific steps for downlink retransmission are as follows: ① Set the first retransmission threshold for the UE's first MAC layer. For example... Figure 7As shown, during the connection between the base station equipment and the UE at the RLC layer, the second RRC layer of the base station equipment reconfigures the maximum number of downlink HARQ retransmissions, Nmax, for the UE via RRC reconfiguration. The first MAC layer sets Nmax to a first retransmission threshold. In some embodiments, Nmax can be set according to the network standard; for example, for NR, Nmax is set to 4, corresponding to the four coding redundancy versions of the baseband. In some embodiments, the HARQ ID can be used to identify whether the data packet is used for setting the first retransmission threshold or other types of data packets. For example, the HARQ ID=1 in the data packet transmitted by the first MAC layer can be used to identify whether it is a data packet used for setting the first retransmission threshold.

[0065] ② Determine that TB2 has reached the maximum number of retransmissions and the last retransmission still failed to be received, such as Figure 7 As shown, when the first MAC layer detects that the PDU with sequence number n1-1 in the second RLC1 entity and the PDU with sequence number nn-1 in the second RLC2 entity on the base station device side have been transmitted Nmax times and the first MAC layer still fails to receive them, the first MAC layer immediately informs each RLC entity of the UE through the last data retransmission indication so that before the T-Reassembly timer expires, it immediately sends an RLC STATUS report to the corresponding RLC entity sender of the base station device, thereby requesting the base station device to retransmit the failed PDU.

[0066] In some embodiments, the logic for the UE to detect that the number of retransmissions of a transport block has reached Nmax is as follows: The UE can identify whether there is a retransmission of the same transport block by using the HARQ ID and NDI carried in the DCI. An NDI of 0 indicates that the transport blocks being transmitted together are being retransmitted, and the HARQ ID can identify the transport blocks being transmitted together. Taking HARQ ID=2 as an example, for the same HARQ process with HARQ ID=2, Nmax is 3. Therefore, if the UE's first MAC layer determines that it has received three consecutive DCI commands with NDI=0 and HARQ ID=1, and the UE has failed to demodulate the PDU with SN=n-1 in this TB block, it means that the MAC layer's retransmission of the TB block with HARQ ID=2 has ended and reception has failed.

[0067] ③ Status report submission, refer to Figure 7As shown, the first MAC layer notifies the corresponding RLC entity to proactively report the RLC layer status report, requesting retransmission of the PDU corresponding to the status report. For example, if PDUn-1 fails, a status report for PDU n-1 is sent; if PDUnn-2 also fails, a status report for PDUnn-2 is sent. When the base station receives the RLC STATUSreport from the UE, it retransmits the PDU corresponding to the status report. In other embodiments, assuming only PDUn-1 reception fails in TB2 and PDUnn-2 reception succeeds, the base station only retransmits PDU n-1.

[0068] Understandably, prior to step S110, the method also includes: The second retransmission threshold is received from the second communication device; wherein the second retransmission threshold is determined by the second communication device based on the communication quality with the first communication device. Use the second retransmission threshold as the first retransmission threshold.

[0069] The second retransmission threshold is the maximum number of retransmissions allowed by the second MAC layer for the target transmission block to be retransmitted, and the first retransmission threshold is the maximum number of retransmissions allowed by the second MAC layer as recorded by the first MAC layer.

[0070] Communication quality can characterize network load status.

[0071] By determining the second retransmission threshold based on the communication quality between the second and first communication devices, the threshold can be dynamically set according to network load during each RLC transmission. For example, when there is a large amount of downlink data requiring scheduling in the base station cell, the number of retransmissions is reduced; otherwise, the number of retransmissions is increased.

[0072] Understandably, referring to Figure 8 As shown, the data retransmission method applied to a second communication device according to this application includes: Step S210: Receive a status report sent by the first communication device; wherein the status report is generated by the first communication device based on the target data unit to be retransmitted corresponding to the target transmission block when it is determined that the number of retransmissions of the target transmission block in the first MAC layer has reached a preset first retransmission threshold. Step S220: Based on the status report, retransmit the target data unit to the first communication device.

[0073] Therefore, when the number of retransmissions of the target transport block at the first MAC layer reaches the first retransmission threshold, it indicates that the second communication device will not send the same target transport block again through the second MAC layer before receiving a retransmission request from the first communication device. At this time, by generating a status report of the target data unit to be retransmitted corresponding to the target transport block when the number of retransmissions of the target transport block at the first MAC layer reaches the first retransmission threshold, it is not necessary to wait for the reassembly timer of the first communication device to expire before notifying the second communication device to retransmit the target data unit. The retransmission of the target data unit does not have to rely heavily on the duration set by the reassembly timer. Thus, while taking into account the reliability of data transmission, the waiting time for the first communication device to send the status report for each target data unit that needs to be retransmitted can be shortened as much as possible, thereby improving the real-time performance of data retransmission.

[0074] The target data unit and the status report are configured accordingly. In some embodiments, the status report carries identification information of the target data unit, thereby determining the target data unit that needs to be retransmitted based on the identification information. This application does not limit the mapping relationship between the status report and the target data unit; for example, it can be a one-to-one correspondence.

[0075] The target transport block is the transport block transmitted from the second MAC layer of the second communication device to the first MAC layer. When the first MAC layer cannot receive the target transport block normally, the second MAC layer will initiate a retransmission for the unreceived target transport block.

[0076] This application does not limit how the timing of generating the status report is determined when the second communication device acts as the receiving end. In some embodiments, when the second communication device acts as the receiving end, data retransmission operations can be performed by referring to steps S110 to S120. In other embodiments, when the transmission scheduling of the first communication device is controlled by the second communication device, the second communication device can also determine whether the transmission block sent by the first communication device has reached the maximum retransmission threshold based on its own scheduling status.

[0077] For example, taking the first communication device as the terminal device and the second communication device as the base station device, and the target transmission block as the uplink transmission block, refer to... Figure 6 As shown, the specific steps of Example 3 of another embodiment of this application are as follows: ① Data unit PDUn-2 starts transmission and reception is normal, such as Figure 6 As shown, the first RLC layer sends the data unit PDUn-2 with the transmission sequence number n-2 to the base station equipment, and PDUn-2 is correctly received by the base station equipment.

[0078] ② Data unit PDUn-1 initiates transmission and determines that reception has failed, such as Figure 6As shown, the first RLC layer continues to transmit n-1 data units PDUn-1. When PDUn-1 fails to be received at the base station equipment side, the MAC layer retransmission is initiated. When the second MAC layer detects that PDUn-1 has reached the maximum number of retransmissions Nmax at the first MAC layer and still fails to be received at the second MAC layer, it is determined that the data unit PDUn-1 has failed to be received at the RLC layer.

[0079] ③ Send the final data indication to the second RLC layer, such as Figure 6 As shown, the second MAC layer immediately informs the second RLC layer via the last data indication that this is the last TB block transmission for n-1 PDUs.

[0080] ④ The second RLC layer immediately sends a status report to the UE, such as Figure 6 As shown, the duration of the T-Reassembly timer is t1. At this time, even if the T-Reassembly timer of the second MAC layer has not expired, the second RLC layer will immediately send a STATUS report to the first RLC layer of the UE, requesting the first RLC layer of the UE to immediately start retransmission for PDU n-1.

[0081] In some embodiments, since the base station acts as the receiver and uplink MAC layer retransmissions are also scheduled by the base station, the base station has a clear understanding of the uplink reception status at both the MAC and RLC levels. Therefore, the number of scheduling attempts can be determined by the base station's own uplink retransmission scheduling count, and whether the UE has reached the maximum retransmission count can be determined based on whether the scheduling count has reached the maximum. If the scheduling count reaches the maximum, it can be considered that the first MAC layer has retransmitted to the maximum number of times, and the second RLC layer needs to send a PDUn-1 STATUS report to the first RLC layer. At this time, if... Figure 6 As shown, assuming the duration of the recombination timer is t1, the reduction in delay is as follows: Figure 6 As shown in t2. At this point, by using different mechanisms to determine the number of retransmissions in different transmission directions, the interaction logic between the first and second communication devices can be simplified, the risk of errors can be reduced, and the real-time retransmission in both transmission directions can be ensured.

[0082] Understandably, the second communication device includes a second MAC layer; the method also includes: When the second MAC layer completes the last retransmission of the target transport block, it sends a retransmission indication signaling corresponding to the target transport block to the first communication device, so that the second communication device can determine, based on the retransmission indication signaling, that the number of retransmissions of the target transport block in the first MAC layer has reached the first retransmission threshold.

[0083] By having the second communication device determine that the target transmission block is the last retransmission, the accuracy of the statistics can be further ensured. This application does not limit the encapsulation format of the retransmission indication signaling; for example, the retransmission indication information can be encapsulated as DCI signaling or MAC CE signaling. Those skilled in the art can selectively set this according to the actual situation.

[0084] Understandably, the method also includes: Obtain the communication quality with the first communication device; Update the second retransmission threshold configured in the second MAC layer based on communication quality. The updated second retransmission threshold is sent to the first communication device so that the first communication device can determine whether to generate a status report based on the updated second retransmission threshold.

[0085] In some embodiments, the second retransmission threshold can be dynamically set as the network load status changes, thereby enabling the first retransmission threshold to be dynamically set as well.

[0086] In summary, the data retransmission method of this application embodiment enables interaction between the RLC layer and the MAC layer. When the STATUS PDU of the RLC layer needs to be reported, by eliminating the waiting time before the T-Reassembly timer expires, the sending end can obtain the RLC STATUS PDU fed back by the receiving end as early as possible, so as to retransmit the NACK RLC data packet as soon as possible, thereby reducing the RLC retransmission latency. This application embodiment can implement the data retransmission method in at least two ways. Method one is semi-static configuration, which configures the total number of retransmissions of the receiving end's MAC layer through RRC, thereby introducing interaction between the RLC and MAC layers. Method two is dynamic interaction, which introduces interaction between the RLC layer and the MAC layer by having the sending end dynamically indicate to the receiving end that the retransmission of the last TB block has been completed. At the same time, this application embodiment can also adapt to data retransmission under different mapping relationships between RLC entities and TB blocks, including mapping from a single RLC AM entity to the MAC layer and mapping from multiple RLC AM entities to the MAC layer.

[0087] Understandably, referring to Figure 9 As shown, one embodiment of this application also provides a communication device, including: At least one processor 901; At least one memory 902 is used to store at least one program that implements the above method when the at least one program is executed by at least one processor 901.

[0088] The memory 902, as a non-transitory network system, can be used to store non-transitory software programs and non-transitory computer-executable programs. Furthermore, the memory 902 may include high-speed random access memory, and may also include non-transitory memory, such as at least one disk storage device, flash memory device, or other non-transitory solid-state storage device. In some embodiments, the memory 902 may optionally include remotely located memories 902 relative to the processor 901, which can be connected to the processor 901 via a network. Examples of such networks include, but are not limited to, the Internet, intranets, local area networks, mobile communication networks, and combinations thereof.

[0089] The memory 902 can be implemented as a read-only memory (ROM), a static storage device, a dynamic storage device, or a random access memory (RAM). The memory 902 can store the operating system and other application programs. When the technical solutions provided in the embodiments of this specification are implemented through software or firmware, the relevant program code is stored in the memory 902 and is called and executed by the processor 901.

[0090] The processor 901 can be implemented using a general-purpose CPU (Central Processing Unit), microprocessor, application-specific integrated circuit (ASIC), or one or more integrated circuits, and is used to execute relevant programs to implement the technical solutions provided in the embodiments of this application.

[0091] In some embodiments, the communication device further includes: The input / output interface 903 is used to implement information input and output; The communication interface 904 is used to enable communication and interaction between this device and other devices. Communication can be achieved through wired means (such as USB, Ethernet cable, etc.) or wireless means (such as mobile network, WIFI, Bluetooth, etc.). The bus transmits information between various components of the device (such as processor 901, memory 902, input / output interface 903, and communication interface 904); The processor 901, memory 902, input / output interface 903, and communication interface 904 can communicate with each other within the device via a bus.

[0092] An embodiment of this application also provides a computer-readable storage medium storing computer-executable instructions for performing the above-described method.

[0093] An embodiment of this application also provides a computer program product, including a computer program or computer instructions stored in a computer-readable storage medium. The processor of a detection device reads the computer program or computer instructions from the computer-readable storage medium, and the processor of a communication device executes the computer program or computer instructions, causing the computer device to perform the above-described method.

[0094] The system architecture and application scenarios described in the embodiments of this application are for the purpose of more clearly illustrating the technical solutions of the embodiments of this application, and do not constitute a limitation on the technical solutions provided in the embodiments of this application. Those skilled in the art will know that as the system architecture evolves and new application scenarios emerge, the technical solutions provided in the embodiments of this application are also applicable to similar technical problems.

[0095] It will be understood by those skilled in the art that all or some of the steps and systems in the methods disclosed above can be implemented as software, firmware, hardware, and suitable combinations thereof. Some or all of the physical components can be implemented as software executed by a processor, such as a central processing unit, digital signal processor, or microprocessor, or as hardware, or as an integrated circuit, such as an application-specific integrated circuit. Such software can be distributed on a computer-readable medium, which can include computer storage media (or non-transitory media) and communication media (or transient media). As is known to those skilled in the art, the term computer storage media includes volatile and non-volatile, removable and non-removable media implemented in any method or technology for storing information (such as computer-readable instructions, data structures, program modules, or other data). Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technologies, CD-ROM, digital versatile disc (DVD) or other optical disc storage, magnetic cartridges, magnetic tape, disk storage or other magnetic storage devices, or any other medium that can be used to store desired information and is accessible to a computer. Furthermore, as is known to those skilled in the art, communication media typically contain computer-readable instructions, data structures, program modules, or other data in modulated data signals such as carrier waves or other transmission mechanisms, and may include any information delivery medium.

[0096] The above description, with reference to the accompanying drawings, illustrates some embodiments of this application, but does not limit the scope of the invention. Any modifications, equivalent substitutions, and improvements made by those skilled in the art without departing from the scope and spirit of this invention should be considered within the scope of this application.

Claims

1. A method for data retransmission, applied to a first communication device, the first communication device including a first Media Access Control (MAC) layer, the method comprising: When the number of retransmissions of the target transport block in the first MAC layer reaches the preset first retransmission threshold, a status report of the target data unit to be retransmitted corresponding to the target transport block is generated. The status report is sent to the second communication device.

2. The data retransmission method according to claim 1, characterized in that, The method further includes: Receive a retransmission indication signaling from the second communication device; When the retransmission indication signaling instructs the target transmission block to complete the last retransmission, it is determined that the number of retransmissions has reached the first retransmission threshold.

3. The data retransmission method according to claim 2, characterized in that, The retransmission indication signaling is either downlink control information (DCI) signaling or media access control unit (MAC CE) signaling.

4. The data retransmission method according to claim 1, characterized in that, The first communication device further includes a first Radio Link Control (RLC) layer, and the method further includes: Based on the cumulative number of retransmissions of transport block control information signaling in the first MAC layer, it is determined whether the number of retransmissions reaches the first retransmission threshold; wherein, the transport block control information signaling is DCI signaling transmitted in pairs with the target transport block.

5. The data retransmission method according to claim 2 or 4, characterized in that, The target transport block carries at least one data unit, and the generation of a status report for the target data unit to be retransmitted corresponding to the target transport block includes: The reception status of each data unit is determined by the first RLC layer; Based on each of the received states, a target data unit is determined from the at least one data unit; Generate a status report corresponding to the target data unit.

6. The data retransmission method according to claim 4, characterized in that, The method further includes: Receive a second retransmission threshold sent by the second communication device; wherein the second retransmission threshold is determined by the second communication device based on the communication quality with the first communication device; Use the second retransmission threshold as the first retransmission threshold.

7. A method for data retransmission, applied to a second communication device, the method comprising: Receive a status report sent by a first communication device; wherein the status report is generated by the first communication device based on the target data unit to be retransmitted corresponding to the target transmission block when it determines that the number of retransmissions of the target transmission block in the first MAC layer has reached a preset first retransmission threshold. Based on the status report, the target data unit is retransmitted to the first communication device.

8. The data retransmission method according to claim 7, characterized in that, The second communication device includes a second MAC layer; the method further includes: When the second MAC layer completes the last retransmission of the target transport block, it sends a retransmission indication signaling corresponding to the target transport block to the first communication device, so that the second communication device can determine, according to the retransmission indication signaling, that the number of retransmissions of the target transport block in the first MAC layer has reached the first retransmission threshold.

9. The data retransmission method according to claim 7, characterized in that, The method further includes: Obtain the communication quality with the first communication device; Update the second retransmission threshold configured in the second MAC layer based on the communication quality. The updated second retransmission threshold is sent to the first communication device so that the first communication device determines whether to generate the status report based on the updated second retransmission threshold.

10. A communication device, the communication device comprising a memory and a processor; Memory is used to store computer programs; The processor is used to execute a computer program and, in executing the computer program, implement the data retransmission method as claimed in any one of claims 1 to 6 or the data retransmission method as claimed in any one of claims 7 to 9.

11. A computer-readable storage medium storing computer-executable instructions, which, when executed by a processor, cause the processor to implement the data retransmission method as described in any one of claims 1 to 6 and / or the data retransmission method as described in any one of claims 7 to 9.

12. A computer program product comprising a computer program or computer instructions stored in a computer-readable storage medium, wherein a processor of a communication device reads the computer program or computer instructions from the computer-readable storage medium, and the processor executes the computer program or computer instructions to cause the communication device to perform a data retransmission method as claimed in any one of claims 1 to 6 and / or a data retransmission method as claimed in any one of claims 7 to 9.

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