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Online fountain code limited feedback method

A fountain code and feedback point technology, which is applied in the limited feedback field of online fountain codes, can solve the problems of inaccurate overhead calculation and low utilization rate of feedback points, and achieve the effect of flexible adaptation

Active Publication Date: 2021-06-18
BEIJING INSTITUTE OF TECHNOLOGYGY
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

[0006] The purpose of the present invention is to overcome the problems of inaccurate overhead calculation and low utilization rate of feedback points in the HTLO method, and proposes a feedback method for online fountain codes, said method is based on integral overhead calculation (IO) and initial degree value distribution The flexible selection strategy (FSS), in the case of fewer feedback times, finds the feedback scheme with the lowest decoding overhead, which is better close to the recovery performance of OFC

Method used

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  • Online fountain code limited feedback method

Examples

Experimental program
Comparison scheme
Effect test

Embodiment 1

[0037] Suppose there are two satellites A and B, each carrying a mobile terminal T A and T B . Now T A Need to confirm T B Whether it is within the communication distance, that is, T A to T B Send a message of length K=10, T B After receiving the TA to reply. Considering the space communication scenario, the online fountain code with strong anti-interference ability is used as the channel coding method between satellites. And because of T B The state is unknown, considering T B to T A In cases where the uplink may be severely blocked, an online fountain code with limited feedback is used.

[0038] During specific implementation, in step 1, the encoding symbol degree is m i When , the sum of the probabilities of "contains only 1 unrecovered coding symbol" and "contains only 2 unrecovered coding symbols" is:

[0039]

[0040] Defined as the effective probability;

[0041] Points at which all contiguity values ​​are valid with equal probability Find all possible...

Embodiment 2

[0077] Assume that there are master A and slave B in the UAV group, each carrying terminal T A and T B . Now A needs to send an attack command to B, that is, T A to T B Send a piece of information with length K=1000. Due to the complex electromagnetic environment of the battlefield, the online fountain code with strong anti-interference ability is used as the channel coding method. Considering that the computing power of the slave machine is relatively limited, and the decoding process cannot occupy too much computing power for combat, an online fountain code with limited feedback is adopted.

[0078] Let K=1000, d=2, β 0 = 0.45. In step 1, since K=1000, there is no β>β at the end of the establishment phase 0 problem, so for β 0 = 0.45 using m 1 =2 as the first degree value. Other steps are similar to Embodiment 1 and will not be repeated here. Finally, using IO-FSS-HTLO, the average overhead is 1277. Much closer to the Online Fountain Code result 1200 than the HTL...

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Abstract

The invention relates to an online fountain code limited feedback method, and belongs to the technical field of channel coding. The method the following steps: 1) determining all possible feedback degree values; (2) establishing an overhead table through points; 3) calculating a feedback point corresponding to the feedback time value; 4) randomly selecting a group of overhead as a threshold; 5) randomly selecting an overhead value in the corresponding column of the degree value, updating the serial number of the degree value, judging whether the serial number is smaller than a threshold, if so, discarding, and if not, recording the current overhead; (6) judging whether the number of the selected degree values reaches the feedback frequency, if not and selectable value existing, skipping to the step (5), if not and selectable value not existing, discarding the sequence, if yes and the total overhead being smaller than the threshold, updating the threshold and recording the sequence, and if yes and the total overhead being larger than the threshold, discarding the sequence; and 7) if iteration reaches a frequency requirement, outputting a degree value sequence, and if not, adding 1 to the number of iterations, and skipping to the step 4). The method can improve the adaptability and reduce the decoding overhead, and the decoding overhead is slowly increased along with the increase of the information length.

Description

technical field [0001] The invention relates to a limited feedback method of an online fountain code, which belongs to the technical field of channel coding. Background technique [0002] Fountain Codes is an effective channel coding method. The encoder can generate infinitely many coded symbols from K source symbols, and the receiver can recover the source symbols from any n coded symbols. Compared with the traditional channel coding method with a fixed code rate, the code rate of the fountain code can be adaptively changed according to the channel conditions without pre-obtaining channel state information, so it is widely used in multimedia communication, satellite communication, data distribution and other scenarios. [0003] With the development of communication technology, more and more communication scenarios begin to appear, which put forward higher requirements for channel coding methods. In emerging communication scenarios such as wireless VR and machine-type commu...

Claims

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Application Information

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IPC IPC(8): H04L1/00
CPCH04L1/0056H04L1/0073
Inventor 费泽松秦梓峻黄靖轩
Owner BEIJING INSTITUTE OF TECHNOLOGYGY
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