Feedback channel transceiving method for data transmission and channel state of wireless ad hoc network

Abstract

The invention relates to the technical field of wireless ad hoc networks, in particular to a feedback channel transceiving method for data transmission and channel state of a wireless ad hoc network, which comprises the following steps of: designing a physical layer feedback channel for indicating receiving information of nodes in other ad hoc networks and an HARQ (Hybrid Automatic Repeat Request) process state currently maintained by the node; other nodes can receive the channel and select a sending mode of retransmission data according to the information; comprising the following steps: step 1, in a wireless ad hoc network, a physical feedback channel (PHCFCH) is used for indicating data transmission between a node and other nodes, an HARQ buffer state of the node and a wireless channel state; and step 2, a control channel PCCH in a special format is used in the wireless ad hoc network and is used for indicating the sending format and the content length of a feedback channel PHCFCH.

Description

Technical Field

[0001] The present invention relates to the technical field of wireless ad hoc networks, and in particular to a method for transmitting and receiving a feedback channel for data transmission and channel status in a wireless ad hoc network. Background Art

[0002] HARQ is a technology that combines forward error correction (FEC) and automatic repeat request (ARQ).

[0003] HARQ is a technology that combines forward error correction (FEC) and automatic repeat request (ARQ). Traditional ARQ is a simple retransmission technology where the sender simply retransmits the data packet that the receiver previously failed to receive. Compared to traditional ARQ, HARQ has several advantages:

[0004] At the underlying physical layer, the receiver feeds back information about reception success or failure to the sender, so that the sender can retransmit as quickly as possible, reducing the waiting delay for ARQ retransmission at the upper layer.

[0005] At the physical layer, HARQ is combined with FEC coding technology to send different versions of encoded redundant bit information (Retransmission Version, RV) in each transmission (initial transmission and retransmission). The receiver saves different versions of the transmission information and merges them, increasing the diversity gain, thereby effectively improving the decoding performance and increasing the reliability of information transmission.

[0006] A necessary prerequisite for HARQ transmission combining is that the receiver can provide HARQ feedback to the sender.

[0007] Although HARQ technology has many advantages, some differences between wireless ad hoc networks and public networks make it difficult to use HARQ technology in wireless ad hoc networks. In a wireless ad hoc network, the receiving node needs to receive information from different sending nodes. A typical wireless ad hoc network may include up to 32 wireless nodes. Therefore, in order to support HARQ:

[0008] 1. Each receiving node needs to feedback the ACK / NACK information received from different nodes. The feedback amount is much greater than the information feedback from each terminal in public network communication.

[0009] 2. The number of HARQ processes that each receiving node needs to maintain also increases significantly.

[0010] Similarly, due to the variability of channel conditions in wireless communications, how the sender determines the modulation and coding format to use is also a key technology. Major modulation formats include BPSK, QPSK, 16-QAM, 64-QAM, 256-QAM, and even higher 1024-QAM and 4096-QAM. Higher modulation formats can transmit more information, but also require higher wireless channel quality. Conversely, lower modulation formats increase the probability of successful reception at the receiver, but transmit less information. The main channel coding rates range from <0.1 to 0.95 or higher. Similarly, higher coding rates require higher wireless channel quality. High channel utilization requires the sender to adaptively adjust the modulation and coding format based on channel conditions. Indiscriminately using low modulation and low coding rates results in low channel utilization. Indiscriminately using high modulation and high coding rates results in frequent reception failures and retransmission requests, which also underutilizes the channel.

[0011] In typical wireless communications, the transmitting base station can determine the modulation and coding format (MCF) to be sent to the terminal based on the CSI (Channel State Information) feedback from the terminal (UE). The base station can configure periodic CSI feedback for the terminal or use the PDCCH to indicate aperiodic CSI feedback commands, instructing the terminal to send CSI feedback. However, in wireless ad hoc networks, due to the presence of multiple transmitting nodes, each transmitting node traverses a different channel to reach a receiving node, resulting in a large amount of feedback information.

[0012] Due to the large amount of feedback information, the terminal feedback channel capacity of the traditional public network is insufficient and difficult to use effectively. If the data channel is used directly or multiplexed into the data channel, normal data transmission will be affected. Summary of the Invention

[0013] The purpose of the present invention is to provide a method for transmitting and receiving a feedback channel for data transmission and channel status in a wireless ad hoc network. By designing a physical layer feedback channel to indicate the reception information of other nodes in the ad hoc network and the HARQ process status currently maintained by this node, other nodes can receive this channel and select a sending method for retransmitted data based on the information.

[0014] To achieve the above object, the present invention provides the following technical solution: a method for transmitting and receiving a feedback channel for data transmission and channel status in a wireless ad hoc network, comprising the following steps:

[0015] Step 1. In wireless ad hoc networks, the physical feedback channel (PHCFCH) is used to indicate data transmission between the local node and other nodes, the HARQ buffer status of the local node, and the wireless channel status.

[0016] Step 2: A control channel PCCH in a special format is used in the wireless ad hoc network to indicate the transmission format and content length of the feedback channel PHCFCH.

[0017] Preferably, a physical HARQ and CSI feedback channel is designed in the wireless ad hoc network, which is used to feedback the ACK / NACK information of the node to all other nodes, the HARQ status information maintained by the node, and optionally including CSI information; at the same time, a simple control channel is designed to indicate the format of the feedback channel.

[0018] Preferably, the wireless ad hoc network may include a maximum of 32 wireless nodes, and the maximum number of HARQ processes that can be accommodated between every two nodes is 15.

[0019] As a preference, if only ACK / NACK is fed back, the information payload of the feedback channel;

[0020] 5 bits represent the node ID, and 2 bits represent the status information of each HARQ process sent by each node to that node:

[0021] 00: No data transmission of this HARQ process is received;

[0022] 01: The data of the HARQ process has been received and decoded successfully;

[0023] 10: Data from this HARQ process is received, decoding fails, and the soft bit information is saved in the HARQ buffer.

[0024] 11: Data received by this HARQ process fails to be decoded, but the soft bit channel is not saved in the HARQ buffer. Possible reasons include: insufficient HARQ buffer or a high-priority channel preempting the HARQ buffer;

[0025] When other nodes receive this feedback channel, they can schedule new transmission or retransmission based on this information.

[0026] Preferably, the HARQ process state is 01: this HARQ process can be used to send new data;

[0027] The HARQ process state is 10: different RV versions can be used to retransmit the data of this process;

[0028] The HARQ process state is 11: the data of this process needs to be retransmitted, and the initial transmission version RV0 needs to be used. This is because the receiver has no previous data to merge, and using RV0 can include as many system bits as possible.

[0029] Preferably, if CSI information is to be fed back, channel quality information CQI and channel rank RI can be fed back to each node, where CQI can be represented by 4 bits and RI can be represented by 1 bit, similar to LTE's broadband CQI / RI; the feedback channel PHCFCH can accommodate a maximum of 31*(5+15*2+4+1)=1240 bits.

[0030] Preferably, a control channel PCCH is designed to indicate the PHCFCH format, and the control channel may include the following contents:

[0031] Number of nodes carried by PHCFCH: 5 bits. When the number of nodes in the network is small, PHCFCH can transmit fewer bits.

[0032] Whether PHCFCH carries CSI feedback: 1 bit;

[0033] PHCFCH transmission modulation and coding level: 4 bits. Since the information carried by PHCFCH is relatively important, a lower modulation level can be used to enhance the protection of QPSK, which can reduce the number of MCS bits.

[0034] PHCFCH transmission resource allocation: the number of bits is determined by the wireless ad hoc network bandwidth;

[0035] In the PHCFCH coding and modulation process, Turbo or LDPC codes are used for channel coding. PHCFCH can select a similar transport block size based on the payload size determined by the format and pad it to the required size. Subsequent CRC, channel coding, rate matching, scrambling, modulation, and resource mapping can be performed in an LTE / NR-compatible manner.

[0036] Preferably, in the coding and modulation process of the PCCH, channel coding adopts convolutional or Polar code; subsequent CRC, channel coding, rate matching, scrambling, modulation, and resource mapping can adopt an LTE / NR compatible approach.

[0037] For the receiver, according to the receiving method similar to LTE / NR, the PCCH is first blindly searched. After completing the decoding of the PCCH, the transmission format and resource occupancy of the PHCFCH are obtained. Then, the PHCFCH is demodulated and decoded to obtain the ACK / NACK and CSI payload bit.

[0038] Preferably, each node in the wireless ad hoc network can obtain the data transmission information and channel status of the node that previously sent PHCFCH feedback based on the payload information, and decide the coding and modulation format to be sent next time, the HARQ process to be used, and the redundant version information.

[0039] The method for transmitting and receiving a feedback channel for data transmission and channel status in a wireless ad hoc network of the present invention has the following advantages: by using the feedback channel PHCFCH, the node transmission in the wireless ad hoc network can use HARQ feedback of different redundancy versions and adaptive modulation and coding technology at the physical layer, thereby improving the wireless resource utilization efficiency and wireless transmission performance of the wireless ad hoc network. BRIEF DESCRIPTION OF THE DRAWINGS

[0040] Figure 1 Schematic diagram of the information payload of the feedback channel for feedback of only ACK / NACK;

[0041] Figure 2 Schematic diagram of the information payload of the feedback channel when K is used to feedback CSI information;

[0042] Figure 3 Schematic diagram of the channel composition and modulation and transmission process of PHCFCH and its control channel PCCH. DETAILED DESCRIPTION

[0043] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative efforts are within the scope of protection of the present invention.

[0044] This solution designs a physical HARQ and CSI feedback channel (PHCFCH) in a wireless ad hoc network. This channel is used to feedback the node's ACK / NACK information for all other nodes, the HARQ state information maintained by the node, and optionally CSI information. A simple control channel is also designed to indicate the format of the feedback channel.

[0045] A typical wireless ad hoc network can include up to 32 wireless nodes, and the maximum number of HARQ processes that can be accommodated between each two nodes is usually 15. Taking the above numbers as an example, if only ACK / NACK is fed back, the information payload of the feedback channel can be as follows: Figure 1 Composition shown:

[0046] 5 bits represent the node ID, and 2 bits represent the status information of each HARQ process sent by each node to that node:

[0047] 00: No data transmission of this HARQ process is received;

[0048] 01: The data of the HARQ process has been received and decoded successfully;

[0049] 10: Data from this HARQ process is received, decoding fails, and the soft bit information is saved in the HARQ buffer.

[0050] 11: Data received by this HARQ process fails to be decoded, but the soft bit channel is not saved in the HARQ buffer. Possible reasons include: insufficient HARQ buffer, high-priority channel preempting the HARQ buffer, etc.

[0051] When other nodes receive this feedback channel, they can schedule new or retransmissions based on this information. For example:

[0052] The HARQ process state is 01: this HARQ process can be used to send new data;

[0053] The HARQ process state is 10: different RV versions can be used to retransmit the data of this process;

[0054] The HARQ process state is 11: the data of this process needs to be retransmitted, but the initially transmitted version RV0 needs to be used. This is because the receiver has no previous data to merge, and using RV0 can include as many system bits as possible.

[0055] Furthermore, if CSI information is to be fed back, channel quality information (CQI) and channel rank (RI) can be fed back to each node, where CQI can be represented by 4 bits and RI can be represented by 1 bit, similar to LTE's broadband CQI / RI, such as Figure 2 shown.

[0056] In this way, the feedback channel PHCFCH can accommodate a maximum of 31*(5+15*2+4+1)=1240 bits.

[0057] Correspondingly, a control channel (PCCH) is designed to indicate the PHCFCH format. The control channel may include the following contents:

[0058] The number of nodes carried by PHCFCH is -5 bits. When the number of nodes in the network is small, PHCFCH can transmit fewer bits.

[0059] Whether PHCFCH carries CSI feedback - 1 bit;

[0060] The PHCFCH transmission modulation and coding level (MCS) of -4 bits is similar to the MCS carried by the PDCCH in public network transmission. Because the information carried by the PHCFCH is relatively important, a lower modulation level (QPSK) can be used for enhanced protection, which can reduce the number of MCS bits.

[0061] The number of bits allocated to the PHCFCH transmission resource is determined by the wireless ad hoc network bandwidth, similar to the resource allocation field carried by the PDCCH in public network transmission.

[0062] The channel composition and modulation transmission process of PHCFCH and its control channel PCCH are as follows: Figure 3 As shown;

[0063] The coding and modulation process for the PHCFCH can be similar to that of the PDSCH in LTE / NR, with Turbo or LDPC codes used for channel coding. Since PDSCH has certain specified transport block sizes, to ensure compatibility with coding and decoding, the PHCFCH can select a similar transport block size based on the payload size determined by the format and pad to the required size. Subsequent CRC, channel coding, rate matching, scrambling, modulation, and resource mapping can be performed using an LTE / NR-compatible approach.

[0064] The coding and modulation process of PCCH can be similar to that of PDCCH in LTE / NR, and the channel coding adopts convolutional or Polar code. The subsequent CRC, channel coding, rate matching, scrambling, modulation, and resource mapping can adopt LTE / NR compatible methods.

[0065] The receiving end uses a similar reception method to LTE / NR, first blindly searching the PCCH. After decoding the PCCH, the transmission format and resource occupancy of the PHCFCH are determined. The PHCFCH is then demodulated and decoded to obtain the ACK / NACK and CSI payload bits. Based on the payload information, each node in the wireless ad hoc network can obtain the data transmission information and channel status previously provided to the node sending the PHCFCH. This information helps determine the coding and modulation format, HARQ process, and redundancy version for the next transmission.

[0066] While embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions, and alterations may be made to these embodiments without departing from the principles and spirit of the invention, and that the scope of the invention is defined by the appended claims and their equivalents.

Claims

1. A method for transmitting and receiving data and feedback of channel status in a wireless ad hoc network, characterized in that: The steps include: Step 1. In wireless ad hoc networks, the physical feedback channel (PHCFCH) is used to indicate data transmission between the local node and other nodes, the HARQ buffer status of the local node, and the wireless channel status. Step 2: A control channel PCCH in a special format is used in the wireless ad hoc network to indicate the transmission format and content length of the feedback channel PHCFCH.

2. The method for transmitting and receiving data and feedback of channel status in a wireless ad hoc network according to claim 1, wherein: A physical HARQ and CSI feedback channel is designed in the wireless ad hoc network. This channel is used to feedback the node's ACK / NACK information for all other nodes, the HARQ state information maintained by the node, and optionally CSI information. A simple control channel is also designed to indicate the format of the feedback channel.

3. The method for transmitting and receiving data and feedback of channel status in a wireless ad hoc network according to claim 1, wherein: A wireless ad hoc network can include a maximum of 32 wireless nodes, and the maximum number of HARQ processes that can be accommodated between every two nodes is 15.

4. The method for transmitting and receiving data and feedback of channel status in a wireless ad hoc network according to claim 3, wherein: If only ACK / NACK is fed back, the information payload of the feedback channel; 5 bits represent the node ID, and 2 bits represent the status information of each HARQ process sent by each node to that node: 00: No data transmission of this HARQ process is received; 01: The data of the HARQ process has been received and decoded successfully; 10: Data from this HARQ process is received, decoding fails, and the soft bit information is saved in the HARQ buffer. 11: Data received by this HARQ process fails to be decoded, but the soft bit channel is not saved in the HARQ buffer. Possible reasons include: insufficient HARQ buffer or a high-priority channel preempting the HARQ buffer; When other nodes receive this feedback channel, they can schedule new transmission or retransmission based on this information.

5. The method for transmitting and receiving data and feedback of channel status in a wireless ad hoc network according to claim 4, wherein: The HARQ process state is 01: this HARQ process can be used to send new data; The HARQ process state is 10: different RV versions can be used to retransmit the data of this process; The HARQ process state is 11: the data of this process needs to be retransmitted, and the initial transmission version RV0 needs to be used. This is because the receiver has no previous data to merge, and using RV0 can include as many system bits as possible.

6. The method for transmitting and receiving data and channel status feedback channels in a wireless ad hoc network according to claim 5, wherein: If CSI information is to be fed back, channel quality information (CQI) and channel rank (RI) can be fed back to each node. CQI can be represented by 4 bits, and RI can be represented by 1 bit, similar to LTE's wideband CQI / RI. The feedback channel PHCFCH can accommodate a maximum of 31*(5+15*2+4+1)=1240 bits.

7. The method for transmitting and receiving data and feedback of channel status in a wireless ad hoc network according to claim 6, wherein: A control channel PCCH is designed to indicate the PHCFCH format. The control channel may include the following: Number of nodes carried by PHCFCH: 5 bits. When the number of nodes in the network is small, PHCFCH can transmit fewer bits. Whether PHCFCH carries CSI feedback: 1 bit; PHCFCH transmission modulation and coding level: 4 bits. Since the information carried by PHCFCH is relatively important, a lower modulation level can be used to enhance the protection of QPSK, which can reduce the number of MCS bits. PHCFCH transmission resource allocation: the number of bits is determined by the wireless ad hoc network bandwidth; In the coded modulation process of PHCFCH, channel coding adopts Turbo or LDPC code; PHCFCH can select a similar transport block size based on the payload size determined by the format and pad it to the required size; subsequent CRC, channel coding, rate matching, scrambling, modulation, and resource mapping can be performed in an LTE / NR compatible manner.

8. The method for transmitting and receiving data and feedback of channel status in a wireless ad hoc network according to claim 7, wherein: In the PCCH coding and modulation process, channel coding uses convolutional or Polar codes. Subsequent CRC, channel coding, rate matching, scrambling, modulation, and resource mapping can adopt LTE / NR compatible methods. For the receiver, according to the receiving method similar to LTE / NR, the PCCH is first blindly searched. After completing the decoding of the PCCH, the transmission format and resource occupancy of the PHCFCH are obtained. Then, the PHCFCH is demodulated and decoded to obtain the ACK / NACK and CSI payload bit.

9. The method for transmitting and receiving data and channel status feedback channels in a wireless ad hoc network according to claim 8, wherein: Each node in the wireless ad hoc network can obtain the data transmission information and channel status of the node that previously sent PHCFCH feedback based on the payload information, and decide the coding and modulation format to be sent next time, the HARQ process to be used, and the redundant version information.

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