Abstract:

A symmetrical interleaver algorithm was developed based on the T-Chaotic mapping and the odd-even protection(TCOP). The T-chaotic mapping was introduced to improve the capability of controllable randomicity of the interleaver and reduce the correlation of the check sequence in the design of odd-even protection. The symmetrical design with the odd-even protection improves the equal protection of the check sequence and simplifies the system structure. Three kinds of TCOP algorithm were proposed and they were compared with the S-chaotic algorithm as well as the interleaver algorithm using the S-chaotic mapping and the odd-even protection(SCOP) in terms of the time delay and the bit error rate. When the length of the frame increases from 512 to 4096, the generating time lag of the S-chaotic is 8 to 676 times longer than that of the TCOP.2, and the SCOP is 8 to 118 times longer than the TCOP.2. When the length of the frame is fixed at 1024, the performance of the TCOP.2 is close to the SCOP, while the coding gain of the TCOP.2 is about 0.3 dB higher than that of the S-chaotic.

Key words: communication technology, Turbo codes, interleaver, chaotic mapping, odd-even protection, symmetry