比特交织Turbo编码调制的8PSK符号映射

Bit-to-Symbol Mapping of 8PSK for BITCM

基于对Turbo编码器输出的系统比特和校验比特的不等错误保护(UEP),提出了一种新的比特交织Turbo编码调制(BITCM)的8PSK符号映射方案,即对于码率为1/3的Turbo码,校验比特映射到8PSK星座点中具有较好传输性能的比特位置上,而系统比特映射到较差传输性能的比特位置上。实现新映射方案的关键是比特交织器的设计。仿真结果表明,新的映射方案在AWGN信道下,误码率为10-3时,可获得大于0.2dB的信噪比增益,而这一增益的获得并没有牺牲频谱效率和增加系统的复杂性。

Based on the unequal error protection （UEP） on the systematic bit and parity check bit output from Turbo encoder,a new 8PSK bit-to-symbol mapping scheme of BITCM （bit interleaved turbo coded modulation） was proposed.That is to say,for rate 1/3 Turbo code, the parity check bits are mapped to the bit position with higher transmission features in 8PSK signal constellation, and the systematic bits are mapped to the bit position with lower transmission features. The key of this new scheme is the design of the bit interleaver. Simulation results show that more than 0.2dB SNR gain can be achieved under AWGN channel and with BER of 10-3, without extra consumption in power, bandwidth efficiency and complexity.