可重构智能表面辅助的四元数调制无线通信系统

四元数调制(Quaternion Modulation,QMod)是一种新型高传输速率的极化调制(Polarized Modulation,PMod)技术,是未来卫星通信系统中极具潜力的多元调制方案之一。QMod将数据块分成4块,其中两块是传输数据信号,另外两块则映射到极化状态部分。每个极化状态块均有一位比特,那么它们可以产生4个极化状态组合。这些状态组合可以用来确定传输数据块在四元数4个不同维度中的位置,从而获得两位额外的传输比特。相比于传统的PMod技术,QMod有着更高的频谱效率。为了进一步挖掘QMod的潜力,介绍了由可重构智能表面(Reconfigurable Intelligent Surface,RIS)辅助的QMod系统,同时推导了该系统的平均误码率理论上界,并在瑞利信道下进行了BER性能仿真。仿真结果表明,RIS辅助的PMod或者QMod系统即便在较低的SNR情况下仍有良好的BER性能,并且随着RIS单元数的增多,其BER性能会逐步提升。

Reconfigurable Intelligent Surface-assisted Quaternion Modulation System

Quaternion modulation(QMod)is a new high transmission rate polarization modulation(PMod)technique,which is a promising multi-level modulation scheme for satellite communications.QMod divides the data block into four sub-blocks,two of which are transmission information parts and the other two are mapped to polarization mode parts.Each polarization mode part has one bit.And four polarization mode combinations they can be generated.These combinations can be used to determine the position of the transmission data block in four different dimensions of the quaternion,resulting in obtaining two additional transmission bits.QMod has a higher spectral efficiency compared to traditional PMod techniques.To further explore the potential of QMod,a QMod system assisted by reconfigurable intelligent surfaces(RIS)is presented,along with the theoretical upper bound on the average bit error rate of the RIS assisted system in the case of a single RIS unit.BER performance simulations are performed under Rayleigh fading channel.Simulation results show that the RIS-assisted PMod or QMod system still has good BER performance even at very low SNR,and the BER performance gradually improves with increasing number of RIS units.