Research On Application And Performance Of Polarization Codes In Vehicular Channels

In recent years,with the advancement of artificial intelligence and driverless technology in intelligent transportation system,the transmission quality requirements for vehicle-to-vehicle communication are increasing.However,with the popularity of the fifth generation communication system,the characteristics of low delay and high bandwidth can well solve the pain points of the current vehicle network.In the face of the complex and changeable transmission environment in the vehicular channel,how to design and optimize the 5G communication system to meet the needs of the Internet of vehicles communication is a hot research topic at present.Polar codes as a coding scheme can theoretically reach the channel capacity,which have the advantages of low coding complexity and errorfree flat layer.However,in the application scenario of 5G Internet of vehicles,as a coding scheme under the control channel,the short code length of polarization code is easy to cause the poor performance of polarization incomplete decoding.In order to meet the requirements of low delay in the Internet of vehicles and combat the harsh time-varying fading transmission environment of the vehicular channel,a reliable decoding scheme with low computational complexity is necessary to design.Therefore the main work of this paper is as follows:1.Aiming at solving the serious performance loss of polarization code under short code lengths,this paper improves the dynamic list successive cancellation bit-flipping decoding algorithm(D-SCF).A D-SCF decoder based on key set is proposed.Compared with the original D-SCF decoding algorithm,the simplified search method based on the key set and the parity cascade construction method are used to effectively reduce the decoding computation and improve the decoding performance,and the performance is more obvious in the case of low code length.2.The probabilistic shaping coding modulation scheme is studied,and the theoretical symbol error rate formula of the shaped non-equal probability M-ASK and QAM signals under AWGN is derived.And through the theoretical formula,it is verified that non-equal probability source such as image source can improve the bit error performance of channel transmission after encryption operation.3.In view of the Doppler effect and multipath delay caused by the Gaussian movement of the transceiver in the vehicular channel,the tapped delay model is used to model and simulate the vehicular channel.The OFDM transmission system model based on polarization code is established in vehicular channel,and the performance of the proposed improved D-SCF decoding algorithm is simulated and evaluated under the system model.Simulation results show that the improved D-SCF decoding algorithm proposed in this paper can achieve better decoding performance with lower computational complexity than CA-SCL decoding in the medium and high SNR(>15d B)vehicular channel transmission environment.