Research On Polar Code Based On Ultra-Reliable Low Latency Communication

As the only channel coding scheme that can theoretically prove to reach the Shannon limit,the polar code has low complexity of both coding and decoding,and it has no error leveling in medium and short code lengths.Polar code is widely considered as the preferred channel coding scheme in the Ultra Reliable Low Latency Communication(URLLC)scenario.Currently,the standardization of the URLLC scenario is still under discussion.Because of the performance requirements of URLLC scenario need to meet 99.999% reliability and end-to-end delay as low as 1ms,the following problems still exist in the URLLC scenario:(1)The 3GPP(3rd Generation Partnership Project)proposal proposed that the telecom transmission data length in the URLLC scenario is 32 bytes,which is far less than the theoretical infinite code length of the polar code,which seriously affects the polarization performance of the subchannels of polar code.Therefore,how to select the subchannels with high reliability and how to measure the reliability of the subchannels are very important for the construction of polar code;(2)The delay requirement in the URLLC scenario is very high,and the conventional construction scheme of the polar code is complicated.Therefore,it is necessary to design a rapid construction method of the polar code while ensuring the performance of the polar code;(3)In the URLLC scenario,the requirement of decoding performance is high.However,the decoding structure of polar code makes its complexity increase with the improvement of performance,so it is necessary to design a solution to reduce the decoding complexity in the URLLC scenario.Therefore,the research work of this thesis is as follows:1.In order to solve the problem that the existing decoding algorithm has to increase the complexity to achieve the URLLC ultra-high reliability requirement,this thesis designs a segmentation adaptive decoding algorithm based on cyclic redundancy check.This algorithm adaptively selects the appropriate decoding list width according to the segmentation check result through a designed list selector.Compared with the traditional algorithm,the complexity of the designed algorithm is reduced while ensuring the decoding performance.2.Due to the commonly used construction algorithms in polar code cannot solve the low complexity construction problem in the URLLC scenario.In this thesis,a low-complexity construction algorithm for polar code based on universal partial order theory and polarization weighting algorithm is designed.This algorithm performs fast sorting of subchannels with the aid of Gaussian approximation algorithm,which greatly reduces the construction complexity compared with the traditional iterative construction algorithm.And because of the auxiliary construction of the Gaussian approximation algorithm,the subchannel sequence constructed by this algorithm is closer to the ideal sequence.3.Combined with the designed low complexity construction and decoding algorithm,the polar code construction-decoding scheme for the URLLC scene is given in this thesis.The simulation comparison with the traditional construction coding scheme proves that the performance and complexity of the scheme are better than the traditional scheme.