CAJ | 학술논문

脉冲位置调制（PPM）无线光通信系统易受到大气湍流影响，针对于此，将Turbo技术引入到PPM的解调和乘积码译码中。基于极大似然准则导出了PPM软检测解调方法，结合分组码的SISO译码，构建了检测解调和译码联合迭代的Turbo结构，推导了其迭代原理算法。仿真分析结果表明，误码性能可随迭代次数增加改善，其中，在大气闪烁指数0.1和误码率10-6条件下，迭代3~5次相比非迭代系统获得了0.8 dB以上的增益。
맥충위치조제（PPM）무선광통신계통역수도대기단류영향，침대우차，장Turbo기술인입도PPM적해조화승적마역마중。기우겁대사연준칙도출료PPM연검측해조방법，결합분조마적SISO역마，구건료검측해조화역마연합질대적Turbo결구，추도료기질대원리산법。방진분석결과표명，오마성능가수질대차수증가개선，기중，재대기섬삭지수0.1화오마솔10-6조건하，질대3~5차상비비질대계통획득료0.8 dB이상적증익。
To reduce the influence of atmospheric turbulence, turbo technique was used in process of PPM demodulation and product code decoding. The soft detection demodulation method of PPM was deduced based on maximum likelihood rules, combined with SISO block decoding, the structure of Turbo demodulation and decoding was constituted, iterate algo-rithm was also given. Simulation results showed that, the performance could be improved with increasing of iterations, and under condition of 0.1 atmospheric index and BER 10-6 , with 3~5 iterations the iterate algorithm would provide more than 0.8 dB gain compared to no-iteration system.