Fountain code decoding method under multi-address channel

Abstract

The invention discloses a fountain code decoding method under a multi-address channel. A sending end adopts a digital fountain code in a increment encoding mode, a receiving end computes initial likelihood ratio of each user, the initial likelihood ratio is sent into a BP decoder to obtain the decoded likelihood ratio, the outside information according to the likelihood ratio before/after the decoding is computed, and then the probability of sending information 0 and information 1 by the user is computed, the probability is used as prior probability to transmit to other user to update the initial likelihood ratio, and iteration updating of the likelihood ratio is performed according to above method till to correct decoding or achieving the maximum iteration time. The BP algorithm and the likelihood ration iteration updating are combined through the method disclosed by the invention, the bit error rate performance and the throughput rate of the multi-user decoding in multi-address interference are improved.

Description

technical field [0001] The invention belongs to the field of wireless communication, and in particular relates to a fountain code decoding method under a multiple access channel. Background technique [0002] Digital fountain code is a new erasure coding method proposed for large-scale network data distribution and reliable transmission. Different from traditional erasure codes, digital fountain codes can independently generate any number of codewords according to a certain probability distribution, and have the characteristics of unlimited code rate or no code rate (rateless). The receiver does not need to care about the specific coded packets and the order of the packets, as long as enough coded packets are received, correct decoding can be achieved. At present, the code types commonly used in the study of fountain codes are LT codes and Raptor codes. In 2002, Luby proposed the first practical digital fountain code - LT code, and designed a practical degree distribution ...

AI Technical Summary

Problems solved by technology

In 2002, Luby proposed the first practical digital fountain code - LT code, and designed a practical degree distribution (robust solitary wave distribution), which can approach the channel capacity in any erasure channel, but its decoding complexity is very high. linear

In the presence of multiple access interference, directly decoding multiple users will result in a lower probability of correct decoding and affect the overall performance of the system

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