MIMO多径衰落信道下的MC-CSK混沌通信

为提高差分混沌键控（DCSK）的传输效率及其在衰落信道下的传输性能，提出了多载波混沌键控（MC-CSK）及类DCSK检测方法，发射端每隔M个OFDM符号间隔插入由混沌参考信号构成的“导频”，在此间隔内其他M-1个OFDM符号即以此混沌参考信号生成的CSK信号，接收端提取“导频”并将之与其他OFDM符号进行相关积分，恢复出M-1比特信息。进一步给出了MIMO多径衰落信道下的MC-CSK分集发射与接收方法，发射端采用不同混沌信号以获得一定的发射分集增益，接收端不需要任何信道先验信息，对各天线的相关积分输出进行等增益合并，可获得空间分集增益和频域分集增益。性能分析和计算机仿真表明，在“导频”插入间隔大于2的情况下，MC-CSK的功率效率大于DCSK，且传输性能优于DCSK。

MC-CSK Chaotic Communications under MIMO Multipath Fading Channels

We consider chaotic digital communications and propose a multi-carrier chaotic shift keying(MC-CSK) communication scheme. In each block size of M OFDM symbols, we use one pilot OFDM symbol inserted time-spaced in all-frequency to transmit the reference chaotic signal and use the other M-1 OFDM symbols to transmit the information-bearing signals each spreaded by the reference chaotic signal. At the receiver, we construct a differential detector after DFT and recover the information bits from the correlations between the pilot OFDM symbol and the other M-1 OFDM symbols in each block size of M. Furthermore, we present a MC-CSK transceiver under MIMO multipath fading channels with no channel state information(CSI), in which a distinct chaotic sequence at each transmit antenna is used to spread the same data symbol and the detection statistics at each receive antenna are combined with equal gain for symbol detection. Both BER performance analysis and computer simulations show that our proposed MC-CSK outperforms differential chaos shift keying(DCSK) in AWGN channels with high bandwidth efficiency for the block size of M>2 and that MC-CSK achieves both spatial diversity gain and frequent diversity gain under MIMO multipath fading channels.