CN-122027084-A - Online fountain code transmission method for dynamic unequal error protection of underwater acoustic network

CN122027084ACN 122027084 ACN122027084 ACN 122027084ACN-122027084-A

Abstract

The invention discloses a dynamic unequal error protection on-line fountain code transmission method of an underwater acoustic network, and particularly relates to the technical field of data transmission of the underwater acoustic network, the method comprises the steps of dividing original data into a most important symbol set (Most Important Symbols, MIS) and a less important symbol set (Least Important Symbols, LIS) according to importance, adopting MIS traversal expansion window strategy in an establishment stage, dynamically setting window selection probability based on unequal error protection requirement, and realizing preferential communication and protection of MIS by adjusting the selection probability of two coding windows; in the completion stage, the MIS is recovered by adopting a sequential window strategy, a dynamic component representing feedback mechanism is designed, only component representing information in each connected component is fed back to reduce feedback expenditure, and a sender dynamically adjusts the data priority according to the decoding progress and feedback elements fed back by a receiver to realize closed-loop self-adaptive transmission. The invention can ensure the data transmission efficiency while realizing the preferential recovery of the key data of the dynamic environment of the underwater acoustic network.

Inventors

DU XIUJUAN
ZHAO LEI

Assignees

上海东海职业技术学院

Dates

Publication Date: 20260512
Application Date: 20260211

Claims (9)

1. The method for transmitting the dynamic unequal error protection on-line fountain codes of the underwater acoustic network is characterized by comprising the following steps of: The method comprises the steps that a sender divides an original business data stream to be transmitted into an original packet set, and divides the original packet set into a most important symbol set MIS and a less important symbol set LIS according to a preset importance level; In the establishment stage, a sender presets the target duty ratio of a maximum communication component LCC, a first coding window only containing MIS original packets and a second coding window containing all the original packets are constructed, window selection probabilities of the first coding window and the second coding window are configured, the windows are selected according to the window selection probabilities, the original packets are selected for coding, and the generated coding packets are sent to a receiver; In the completion stage, the receiver preferentially sets MIS as a current decoding window to decode, identifies connected components in the decoding diagram aiming at unrecovered original packets, determines a component representative belonging to the current decoding window from all connected components to form a component representative set, packages the component representative set as a component representative feedback packet and sends the component representative feedback packet to the sender; The sender analyzes the component representative set according to the component representative feedback packet, decides whether to adjust the data priority according to the feedback information, selects the component representative to encode and send, and realizes closed-loop self-adaptive transmission until the session is completed.
2. The method for transmitting the dynamic unequal error protection online fountain code of the underwater acoustic network according to claim 1, wherein in the establishing stage, a sender maintains a traversal set to record original packets which are already involved in encoding in a first encoding window, when the first encoding window is selected, the sender preferentially selects the original packets from MIS original packets which are not yet entered into the traversal set to participate in encoding, and moves the selected original packets into the traversal set, and when the MIS original packets corresponding to the traversal set are exhausted, the sender randomly selects the original packets from the first encoding window to keep encoding continuity.
3. The method for dynamically unequal error protection on-line fountain code transmission of an underwater acoustic network according to claim 1, wherein the establishment phase encoder periodically evaluates the residual capacity of the node or the change condition of the network environment, determines the parameter adjustment requirement, and adjusts the window selection probability according to the parameter adjustment requirement. When parameters need to be adjusted, a sender aims at guaranteeing MIS priority protection and performs shrinkage configuration on the LIS unequal error protection parameters.
4. The method of claim 1, wherein the encoded packets at least comprise an original packet total number field, an encoding type field for distinguishing an establishment phase from a completion phase, a transmission encoded packet sequence number SN, an original packet ID list participating in encoding, a feedback type field, and a data load.
5. The method of claim 4, wherein the receiver estimates a channel packet loss rate based on a difference between a sequence number SN of a transmission encoded packet and a number of actually received encoded packets, and carries the channel packet loss rate in a component representative feedback packet for the sender to adjust the data priority.
6. The method of claim 1, wherein the receiver uses a sequence window decoding strategy in the completion stage, wherein the receiver continues to decode the sequence window in priority as long as the sequence window corresponding to the original packet containing MIS and not yet recovered is not empty, until the original packet is completely recovered, and then switches to the sequence window corresponding to the original packet containing LIS and not yet recovered.
7. The method for transmitting the dynamic unequal error protection online fountain code of the underwater acoustic network according to claim 1, wherein the rule that the receiver determines the component representation from all the connected components is that any one of the unrecovered original packets belonging to the current decoding window is selected as the component representation of the connected component where the original packet belongs from the current decoding window in the unrecovered original packets corresponding to the current window to be decoded, and each connected component is represented by only one component.
8. The method of claim 1, wherein the component representative feedback packet includes a channel packet loss rate estimated by a receiver, a current decoding window sequence number field, an original packet number field included in a current decoding window, and a dynamic adjustment status field representing a WCRS field of a component representative set in a bitmap form, each bit of the WCRS field corresponds to an original packet sequence in the current decoding set, and the corresponding bits of the original packets selected as the component representative are 1 and the rest are 0.
9. The method for transmitting the dynamic unequal error protection online fountain code of the underwater acoustic network according to claim 1, wherein in the completion stage, a sender rejects one component representation from a locally maintained component representation set after selecting the component representation for coding each time, when the sender finds that the maintained current window component representation set is empty, initiates a component representation feedback request to acquire a new component representation feedback packet and update the component representation set, and the sender carries out dynamic self-adaptive adjustment on the data priority according to the channel packet loss rate and the dynamic adjustment state in the feedback information.

Description

Online fountain code transmission method for dynamic unequal error protection of underwater acoustic network Technical Field The invention relates to the technical field of underwater acoustic network data transmission, in particular to an online fountain code transmission method for dynamic unequal error protection of an underwater acoustic network. Background The underwater acoustic network transmission technology is mainly used for data and instruction exchange in the scenes of ocean observation, submarine equipment coordination, underwater sensor networking and the like. Due to the narrow bandwidth, time-prolonged and significant fluctuation of link state with sea state and relative motion of the underwater acoustic channel, engineering systems often need to accomplish reliable transmission and session convergence with less feedback overhead. Around the above requirement, the prior art generally adopts a non-rate coding thought such as fountain codes, and the like, and continuously transmits coding packets to resist packet loss and burst fading, but the difficulty of realization still exists in how to adjust the coding behavior on line and give consideration to the priority recovery of key data under the underwater acoustic network condition. The existing underwater service data have larger differences, such as alarm and control data are more required to be recovered first than common observation data. The original package can be divided into a most important symbol set MIS and a less important symbol set LIS according to importance in engineering, and unequal error protection is carried out. However, the lack of on-line constraint corresponding to the connectivity evolution of the decoding graph can cause two problems, namely, firstly, the encoding is scattered too early before the key data form an effective connection structure, which can result in the longer time delay of key data recovery, and secondly, the probability of selecting only MIS windows is maintained for a long time for enhancing the key data protection, which can impair the efficiency of the overall decoding connectivity formation, and cause the decoding graph to fail to reach the target scale quickly, slow the completion of the session and consume energy. Meanwhile, the capability of the underwater sound reverse channel is limited, if the transmitter is driven to adjust by adopting the full decoding state report, the length of a feedback packet is too long, the feedback frequency is too high, closed-loop control cannot stably run, and when an effective closed loop is lacking, the transmitter is difficult to timely converge redundant transmission under the dynamic condition of a link, so that transmission resource waste is caused. In addition, during the decoding completion phase, the receiving side often still has unrecovered original packets, and needs to further organize the decoding process and form a closed loop with the transmitting side. If a low-overhead progress expression mode is lacking, a sender has difficulty in accurately grasping a decoding bottleneck and implementing targeted coding, so that a completion stage is prolonged. The prior thought proposes to recover the MIS by adopting a sequence window in the completion stage and introduce component representative feedback to reduce the return cost, but how to stably combine the feedback with on-line coding adjustment and realize the controllable convergence termination of the session under the conditions of the water sound long time delay and the link fluctuation is still a problem to be solved in the prior art. Disclosure of Invention In order to overcome the above-mentioned drawbacks of the prior art, an embodiment of the present invention provides an online fountain code transmission method for dynamic unequal error protection of an underwater acoustic network, so as to solve the problems set forth in the above-mentioned background art. In order to achieve the above purpose, the present invention provides the following technical solutions: An underwater acoustic network dynamic unequal error protection on-line fountain code transmission method comprises the following steps: The method comprises the steps that a sender divides an original business data stream to be transmitted into an original packet set, and divides the original packet set into a most important symbol set MIS and a less important symbol set LIS according to a preset importance level; In the establishment stage, a sender presets the target duty ratio of a maximum communication component LCC, a first coding window only containing MIS original packets and a second coding window containing all the original packets are constructed, window selection probabilities of the first coding window and the second coding window are configured, the windows are selected according to the window selection probabilities, the original packets are selected for coding, and the generated coding packets are sent to a receiver; In