The Performance Research Of Bicm-id Systems

Bit-interleaved Coded Modulation with Iterative Decoding (BICM-ID) is an effective coding modulation scheme to increase the transmission efficiency of wireless channel. It combine coding and modulation techniques, by designing the signal constellation mapping program, changing the most Hamming distance into the largest Euclidean distance among the code word. The joined of bit-interleaver, increasing the system diversity order and improved the system performance in fading channel. At the receiver, by information transmission between demodulator and decoder, BICM-ID both get benefits and a better realization for Maximum Likelihood decoding.At present, the study of BICM-ID system focused on the design of constellation mapping, interleave and error-correcting coding, as well as the combination with advanced technologies, such as the multi-antenna (MIMO), space-time coding (STCM), and orthogonal frequency division multiplexing (OFDM) etc. Although much of success has been achieved, there are still have some problems, for the comprehensive study of error-correcting coding, the performance of BICM-ID system in the impulse noise channel and so on. This paper mainly solve these problems mention above, Firstly, study the performance impact of error-correcting coding method for BICM-ID system, introduction the convolutional code, Turbo code and LDPC codes Encoding and Decoding principles details, and different coding schemes BICM-ID system, make a comprehensive comparison.In addition, this paper analyze the iterative decoding algorithm and the BICM-ID system performance under theα-stable symmetry (SaS) distribution of impulse noise channel. In order to reduce the complexity of the external soft information computing, Least-Squares measure of the external soft information has proposed. To overcome the disadvantages caused by the least square measure, for the further reliability of the system improved, the Huber function was proposed to compute the external soft information. The final Monte Carlo Simulation demonstrate that using Huber function calculated the external soft information can make BICM-ID system obtain better BER performance under theα-stable symmetry (SaS) distribution of impulse noise channel.