说明：  针对极低信噪比条件下的传输， 研究了极低码率 Turbo 码的编译码器结构， 仿真分析了其性能。提出了针对极低信噪比条件下的传输， 研究了极低码率 Turbo 码的编译码器结构， 仿真分析了其性能。
(Aiming at the transmission under very low signal-to-noise ratio (SNR), the structure of the encoder and decoder for very low bit-rate Turbo code is studied, and its performance is analyzed by simulation.)