Wireless ad hoc network HARQ method and system based on sliding window

Abstract

The invention discloses a wireless ad hoc network HARQ (Hybrid Automatic Repeat Request) method based on a sliding window, which comprises the following steps: setting a sending window and a corresponding receiving window for sending and receiving data packets, and if all the data packets in the sending window are successfully sent to the receiving window and are correctly received, replying an ACK (Acknowledgement Character) by the receiving window; otherwise, only the failed data packet is retransmitted; the size of the sliding window, the number of the HARQ processes and the link quality are organically combined, the size of the sliding window and the number of the HARQ processes are dynamically adjusted, a new HARQ-based communication method is formed, the number of information interaction times is reduced, the system overhead is reduced, and the throughput of the system and the reliability of data transmission under the same link quality are effectively improved.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless ad hoc network communication, in particular to a wireless ad hoc network HARQ method and system based on a sliding window. Background Art

[0002] At present, wireless ad hoc network equipment has been widely used in both private and civilian fields. Improving system throughput (effectiveness) and data transmission reliability and reducing system overhead are key technologies for wireless ad hoc network communication equipment. HARQ (Hybrid Automatic Repeat reQuest) retransmission technology is widely used in LTE and 5G systems, but its implementation mechanism still has many shortcomings in improving system throughput, effectiveness, data transmission reliability and reducing system overhead, and there is room for improvement. Summary of the invention

[0003] Purpose of the invention: The purpose of the present invention is to provide a HARQ method and system for wireless ad hoc networks based on sliding windows. By introducing a sliding window and organically combining the sliding window size, the number of HARQ processes and the link quality, a new HARQ-based communication technology is formed to improve system throughput and data transmission reliability and reduce system overhead.

[0004] Technical solution: The sliding window-based wireless ad hoc network HARQ method described in the present invention sets a sending window and a corresponding receiving window for sending and receiving data packets, and the window sizes of the sending window and the receiving window are the same; if all data packets in the sending window are successfully sent to the receiving window and are correctly received, the receiving window replies with an ACK; if any data packet in the sending window is not correctly received by the receiving window, the receiving window replies with a NACK indicating that the data packet fails to be received and requests retransmission; the sending end adds the data packet to the next sending window and resends it.

[0005] Furthermore, the window size is dynamically adjusted according to the link quality, and the window size decreases as the link quality increases.

[0006] Furthermore, the link quality is an average packet loss rate E of several sending windows and receiving windows. When 0≤E<5%, the window size is increased to the maximum; when 5%≤E<10%, the current window size is maintained unchanged; when E≥10%, the window size is reduced to the minimum.

[0007] Furthermore, the window size is taken from the set {1, 4, 8, 16}.

[0008] Furthermore, the data packets in the sending window adopt an asynchronous transmission mechanism, and a plurality of HARQ processes simultaneously send and receive the data packets in the sending window and the receiving window.

[0009] Furthermore, the number T of the HARQ processes is dynamically adjusted according to the window size N, where T=[(N+1) / 2], and [·] represents rounding.

[0010] The sliding window-based wireless ad hoc network HARQ system described in the present invention sets a sending window and a corresponding receiving window for sending and receiving data packets, and the window sizes of the sending window and the receiving window are the same; if all data packets in the sending window are successfully sent to the receiving window and are correctly received, the receiving window replies with an ACK; if any data packet in the sending window is not correctly received by the receiving window, the receiving window replies with a NACK indicating that the data packet fails to be received and requests retransmission; the sending end adds the data packet to the next sending window and retransmits it.

[0011] Furthermore, the window size is dynamically adjusted according to the link quality, and the window size decreases as the link quality increases; the link quality is the average packet loss rate E of several sending windows and receiving windows, when 0≤E<5%, the window size is increased to the maximum, when 5%≤E<10%, the current window size is maintained unchanged, and when E≥10%, the window size is reduced to the minimum.

[0012] Furthermore, the data packets in the sending window adopt an asynchronous transmission mechanism, and a plurality of HARQ processes simultaneously send and receive the data packets in the sending window and the receiving window; the number T of the HARQ processes is dynamically adjusted according to the window size N, T = [(N+1) / 2], [·] represents rounding.

[0013] The electronic device described in the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and is characterized in that when the computer program is loaded into the processor, the sliding window-based wireless ad hoc network HARQ method is implemented.

[0014] Beneficial effects: Compared with the prior art, the advantages of the present invention are: (1) In the HARQ implementation scheme, the present invention performs transmission feedback in units of windows and can dynamically release HARQ processes, thereby reducing the number of information exchanges and system overhead. (2) In the HARQ implementation scheme, the present invention introduces a sliding window and can dynamically adjust the sliding window size and the number of HARQ processes according to the link quality of the communication link, thereby effectively improving the system throughput (effectiveness) and data transmission reliability under the same link quality. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1A schematic diagram of a sending window according to an embodiment of the present invention;

[0016] Figure 2 A schematic diagram of a receiving window according to an embodiment of the present invention;

[0017] Figure 3 A schematic diagram of HARQ multi-process processing according to an embodiment of the present invention;

[0018] Figure 4 This is a schematic diagram of ACK transmission feedback according to an embodiment of the present invention;

[0019] Figure 5 This is a schematic diagram of requesting retransmission when data packet acceptance fails according to an embodiment of the present invention. DETAILED DESCRIPTION

[0020] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0021] 1. Introduce a sliding window into the HARQ solution.

[0022] The sliding window is divided into a sending window and a receiving window, each of which is a buffer zone opened up in the system to store data to be sent and received.

[0023] Send window as Figure 1 As shown, it consists of the following four parts.

[0024] (1) Data that has received an ACK packet indicates that the receiving window has received the corresponding data and can be overwritten by new data.

[0025] (2) Data that has been sent but for which an ACK packet has not yet been received.

[0026] (3) Data that is allowed to be sent but has not yet been sent.

[0027] (4) Data that is not allowed to be sent, data outside the sending window, needs to wait before being sent.

[0028] The receiving window is Figure 2 As shown, it consists of the following three parts.

[0029] (1) Data has been received and an ACK packet has been sent.

[0030] (2) The data in the receive window stores the data that is currently allowed to be received.

[0031] (3) Data that has not been received and is unacceptable.

[0032] 2. The data in the sliding window adopts an asynchronous transmission mechanism.

[0033] Multiple HARQ processes send and receive data packets in the window simultaneously, such as Figure 3 As shown. Continuously send data of the window size at a time, a batch of window size data can be sent by the receiving end with one ACK, and only NACK is replied to request retransmission when retransmission is selected. Only one transmission feedback is performed for one window, as shown Figure 4 shown.

[0034] For example, assuming that the sending and receiving windows are both 8, the sender first sends packets 1-8, and the receiving end decodes and verifies the packets. If the 8 packets are received correctly, an ACK is replied to indicate that all 8 packets in the window are received correctly. The sender shifts the window to the right and continues to send packets 9-16. If the 3rd and 5th packets among the 8 packets fail to be verified, the receiving end sends a NACK to the sender to indicate that the 3rd and 5th packets failed to be received and request retransmission. The sending end shifts the window to the right by 6 bits and continues to put the 3rd and 5th packets into the window, that is, sends packets 3, 5, and packets 9-14. This process is repeated until all data packets are sent and received correctly. Figure 5 shown.

[0035] The sliding window HARQ does not confirm the reception of each data packet, but only confirms the correct reception of all data packets in the entire window and replies with an ACK signal. When some data packets are received incorrectly, only a NACK signal is replied to request the retransmission of these data packets, thereby reducing the number of signaling interactions.

[0036] 3. Dynamic adjustment of sliding window size.

[0037] The sliding window size N is dynamically adjusted according to the link quality. N is taken from the set {1, 4, 8, 16}. The link quality takes the average packet loss rate E of 10 windows. When 0≤E<5%, the window size is increased to the maximum. When 5%≤E<10%, the current window size is maintained unchanged. When E≥10%, the window size is reduced to the minimum.

[0038] 4. Dynamic adjustment of the number of HARQ processes.

[0039] The number of HARQ processes T is dynamically adjusted according to the window size, T = [(N+1) / 2], that is, (N+1) / 2 is rounded up.

[0040] The sliding window-based wireless ad hoc network HARQ system described in the present invention sets a sending window and a corresponding receiving window for sending and receiving data packets, and the window sizes of the sending window and the receiving window are the same; if all data packets in the sending window are successfully sent to the receiving window and are correctly received, the receiving window replies with an ACK; if any data packet in the sending window is not correctly received by the receiving window, the receiving window replies with a NACK indicating that the data packet fails to be received and requests retransmission; the sending end adds the data packet to the next sending window and retransmits it.

[0041] The electronic device described in the present invention includes a memory, a processor, and a computer program stored in the memory and executable on the processor, and is characterized in that when the computer program is loaded into the processor, the sliding window-based wireless ad hoc network HARQ method is implemented.

[0042] The computer-readable storage media may include RAM, ROM, EEPROM, CD-ROM or other optical disk storage, magnetic disk storage or other magnetic storage devices, flash memory, or any other medium that can be used to store the desired program code in the form of instructions or data structures and that can be accessed by a computer.

[0043] The processor is used to execute the computer program stored in the memory to implement each step of the method involved in the above embodiment.

Claims

1. A sliding window-based wireless ad hoc network HARQ method, characterized in that: A sending window and a corresponding receiving window are set for sending and receiving data packets. The window sizes of the sending window and the receiving window are the same. If all data packets in the sending window are successfully sent to the receiving window and are correctly received, the receiving window replies with an ACK. If any data packet in the sending window is not correctly received by the receiving window, the receiving window replies with a NACK indicating that the data packet has failed to be received and requests retransmission. The sender adds the data packet to the next sending window and resends it.

2. The sliding window-based wireless ad hoc network HARQ method according to claim 1, characterized in that: The window size is dynamically adjusted according to the link quality, and the window size decreases as the link quality increases.

3. The sliding window-based wireless ad hoc network HARQ method according to claim 2, characterized in that: The link quality is the average packet loss rate E of several sending windows and receiving windows. When 0≤E<5%, the window size is increased to the maximum. When 5%≤E<10%, the current window size is maintained unchanged. When E≥10%, the window size is reduced to the minimum.

4. The sliding window-based wireless ad hoc network HARQ method according to claim 2, characterized in that: The window size is taken from the set {1, 4, 8, 16}.

5. The sliding window-based wireless ad hoc network HARQ method according to claim 1, characterized in that: The data packets in the sending window adopt an asynchronous transmission mechanism, and a plurality of HARQ processes simultaneously send and receive the data packets in the sending window and the receiving window.

6. The sliding window-based wireless ad hoc network HARQ method according to claim 5, characterized in that: The number T of the HARQ processes is dynamically adjusted according to the window size N, where T=[(N+1) / 2], and [·] represents rounding.

7. A wireless ad hoc network HARQ system based on sliding window, characterized in that: A sending window and a corresponding receiving window are set for sending and receiving data packets. The window sizes of the sending window and the receiving window are the same. If all data packets in the sending window are successfully sent to the receiving window and are correctly received, the receiving window replies with an ACK. If any data packet in the sending window is not correctly received by the receiving window, the receiving window replies with a NACK indicating that the data packet has failed to be received and requests retransmission. The sender adds the data packet to the next sending window and resends it.

8. The sliding window-based wireless ad hoc network HARQ system according to claim 7, characterized in that: The window size is dynamically adjusted according to the link quality, and the window size decreases as the link quality increases; The link quality is the average packet loss rate E of several sending windows and receiving windows. When 0≤E<5%, the window size is increased to the maximum. When 5%≤E<10%, the current window size is maintained unchanged. When E≥10%, the window size is reduced to the minimum.

9. The sliding window-based wireless ad hoc network HARQ system according to claim 7, characterized in that: The data packets in the sending window adopt an asynchronous transmission mechanism, and a plurality of HARQ processes simultaneously send and receive the data packets in the sending window and the receiving window; the number T of the HARQ processes is dynamically adjusted according to the window size N, T=[(N+1) / 2], [·] represents rounding.

10. An electronic device comprising a memory, a processor, and a computer program stored in the memory and executable on the processor, characterized in that: When the computer program is loaded into a processor, the sliding window-based wireless ad hoc network HARQ method according to any one of claims 1 to 6 is implemented.

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