改进型统计幅度成形在OFDM中的设计

Improved Probabilistic Amplitude Shaping for OFDM

统计幅度成形(PAS)可使加性高斯白噪声(AWGN)信道以低于香农信道容量的任意速率进行传输。文章讨论了改进型的统计幅度成形,将统计幅度成形与正交频分复用(OFDM)相结合用于频率选择性衰落信道中。相比直接在每个OFDM子信道中使用统计幅度成形,改进型统计幅度成形只使用一个概率分布匹配器(CCDM)来产生成形比特。改进型统计幅度成形缩小了成形间隔,并实现了传输速率的匹配。从仿真结果可以看出,在误码率低于10-3的情况下,相同的误码率改进型成形分布的传输速率比均匀分布的传输速率高0.07 bit/s/Hz,只低于香农限0.24 bit/s/Hz,即证明改进型统计幅度成形比均匀分布能以更高的传输速率可靠的传输数据。

Probabilistic amplitude shaping permits to transmit data at any rate below Shannon capacity in AWGN channel with only a few error control codes. In this paper an improved scheme of probabilistic amplitude shaping is applied in OFDM system against fre-quency selective fading channels. Instead of using constant composition distribution matcher （CCDM） in each OFDM sub- channels, the improved scheme uses only one CCDM to produce shaped bit streams. Simulation results show that the data rate of shaped dis-tribution is 0.07bits/ s/Hz higher than the uniform distribution under frame error rate of 10-3, only 0.24 bits/ s/Hz less than Shannon limit.