A Decoding Method of Tail-biting Convolutional Codes

Abstract

The invention discloses a tail-biting convolution code decoding method. Based on a circular Viterbi decoding algorithm, impossible initial states are eliminated one by one by iteration according to a received soft information sequence, and an optimal tail-biting path is found finally. With the adoption of the tail-biting convolution code coding method disclosed by the invention, all the impossible states are eliminated by multiple iterations, only the initial state of the tail-biting path which is most similar to a receiving sequence can survive, and finally, the initial state is subjected to algorithm convergence to the optimal tail-biting path and outputted. In addition, the metric of a maximum likelihood tail-biting path is updated through the obtained survived tail-biting path, the impossible initial state is eliminated from the initial states, algorithm non-convergence caused by a circular trap problem is effectively solved, the dilemma that a tail-biting convolution code does not have a practical optimal coding algorithm is solved, and the complexity of the existing decoding scheme is lowered.

Description

technical field [0001] The invention belongs to the field of information technology, and relates to a decoding method, in particular to a tail-biting convolutional code decoding method. Background technique [0002] The tail-biting convolutional code not only eliminates the code rate loss caused by initializing the encoder with known bits, but also provides the same protection ability for all information bits. It is precisely because of these advantages of the tail-biting convolutional code that it is widely used in various communication systems as a coding method for control signaling. For shorter information sequences, tail-biting coding can protect the code rate considerably. For example, the broadcast channel in LTE has a total of 40 bits after adding cyclic redundancy check bits. If the 40-bit information sequence does not need tail-biting If encoded in the same way, the bit rate loss will reach 13%. At present, systems using tail-biting convolutional codes as communi...

AI Technical Summary

Problems solved by technology

This type of decoder uses a completely different search method in the two steps, which is too complex for practical applications

And although this type of algorithm reduces part of the amount of calculation, the heuristic search used requires a large number of stacking and popping operations, queue sorting operations, and the most important thing is that the utilization rate of storage space is low.

Since space must be allocated according to the maximum storage space when allocating space, this leads to low utilization of a large amount of storage space

Although the number of branches searched by this type of algorithm is greatly reduced compared with the WAVA algorithm in the second step, the whole algorithm is executed serially because it is guided by the heuristic function to search for the path with the minimum value of the current f function. The Viterbi Algorithm with Period Greater Than 2 Cycles

Images