直接序列扩频分组映射码索引调制

Direct Sequence Spread Spectrum Block Mapping Code Index Modulation

针对直接序列扩频码索引调制发射端使用大量伪随机(PN)码的问题,提出了一种使用较少PN码的分组映射码索引调制方案。该方案在发射端并行设置多个调制子块独立进行幅相调制,同时集中选取各调制子块间同相、正交支路扩频所需的PN码,经索引值大小排序后依次扩频各调制子块中调制符号的同相、正交分量。分析和仿真结果表明,相同频谱效率条件下所提方案比直接序列扩频码索引调制方案使用的PN码个数更少,并在加性噪声信道下,信噪比高于10 dB时,保持着约1 dB的误比特率性能优势,并远优于空间调制在最优检测算法下的误比特率性能。

To solve the problem of us ing large quant it ies of pseudo random（PN） codes at transmitter of the direct sequence spread spectrum code index modulation （ DSSS-CIM）,this paper proposes a new scheme named block mapping code index modulation by using less PN codes. This scheme sets multiple modulation sub-blocks in parallel to modulate independently,at the same time,it picks up PN codes that are needed in -phase and orthogonal branch intensively,and then spreads the inphase and orthogonal component of the modulation symbol after sequenced by the index value. The analysis and simulation results shows,at the same spectral efficiency,this scheme uses less PN codes than DSSS-CIM,and keeps about -1 dB bit error rate（ BER） advantage when the signal-to-noise ratio（SNR） is higher than 10 dB under the additive noise channel. What＇s more,its performance is much superior to that of the spatial modulation by using the maximum likelihood detector.