IEEE802.16e中的卷积Turbo码编译码算法研究

为了分析不同设计参数对IEEE802.16e中卷积Turbo码(CTC)性能的影响以及对比IEEE802.16e支持的CTC和卷积码的编码性能,介绍了IEEE802.16e中的CTC的编码过程,给出了编码过程中的循环状态确定方法的推导过程,分析了CTC的迭代译码结构和译码算法,最后对CTC的性能进行了仿真.仿真结果表明:在相同码率和相同调制方式下CTC的编码增益要比卷积码大,采用CTC比采用卷积码有着明显的性能优势.因此在码率较低、信道状况较好或对系统实时性要求严格的情况下,可考虑使用卷积码,以降低信道编码的复杂度;而在码率较高、信道状况较差或对误码率要求严格时,可考虑选用CTC编码方案,以保证通信的可靠性.

Encoding and decoding algorithm for convolutional Turbo code in IEEE802.16e

In order to analyze the impact of CTC performance with different coding parameters and to compare the performance of CTC with the performance of convolutional codes both supported by IEEE802.16e, coding scheme of CTC used in IEEE802.16e is introduced and the derivation for determination method of circular state in encoding process is presented. Then iterative decoding structure and decoding algorithm of CTC is analyzed and the performance of CTC is simulated. Simulation results show that: in the same code rate and the same modulation mode CTC has a larger coding gain than the convolutional codes ,Therefore, when code rate is low, channel condition is good and real-time requirement is strict, convolutional codes can be used in order to reduce the complexity of channel coding; While when code rate is high, channel condition is poor and the BER requirement is strict, CTC encoding scheme should be used in order to ensure the reliability of communication.