Research On Key Technology Of Intelligent Reflecting Surface Aided Index Modulation

In recent years,the Intelligent Reflecting Surface(IRS)technology has attracted great attention in the wireless communication field due to its excellent characteristics such as low cost,easy deployment,low power consumption,and can be used to control the wireless propagation environment.On the other hand,Index Modulation(IM)technology transmits information through indexes of different carrier switch states,which not only improves energy efficiency and spectral efficiency,but also reduces bit error rate and computational complexity,making it very suitable for next-generation wireless communication systems.Therefore,combining the IRS technology with the IM technology is expected to further improve the performance of the communication system.But for a communication system,the acquisition of Channel State Information(CSI)is extremely important.In general,the receiving end needs to obtain CSI for information demodulation,and CSI estimation has always been a difficult subject.In order to realize a communication scheme with high efficiency,low complexity and better bit error rate performance,the following research work is carried out in this paper:(1)Research on wireless communication scheme based on IRS-assisted IM in the case of known CSI.As an important member of IM technology,Spatial Modulation(SM)technology has the advantages of good bit error rate performance and high spectral efficiency.On the basis of related research,this paper proposes an IRS-assisted Joint Virtual SM(IRS-JVSM)scheme.The IRS-JVSM scheme transmits information by jointly indexing transmit antennas,receive antennas and virtual modulation symbols,thereby improving the transmission efficiency of the IRS-assisted wireless communication system.On this basis,this paper deduces the theoretical bit error rate of the IRS-JVSM scheme by combining the upper bound technique.The simulation results show that,compared with the existing IRS-assisted wireless communication schemes,the IRS-JVSM scheme not only has higher spectral efficiency,but also has better bit error rate performance.On the other hand,based on IRS reflection modulation(RM),this paper proposes a reflection modulation combined with spatial modulation(RM aided SM,RM-SM)scheme.In the RM-SM scheme,the information bits can be transmitted through the IRS reflection pattern index in addition to the transmit antenna index and modulation symbol.RM-SM can not only achieve the same transmission rate as the IRS-JVSM scheme,but also has another advantage in that it does not need to acquire CSI at the IRS side.In addition,this paper also analyzes the theoretical value of the bit error rate of the RM-SM scheme.Finally,simulation experiments show that the RM-SM scheme can achieve good bit error rate performance while achieving high transmission efficiency.(2)Research on wireless communication scheme based on IRS-assisted IM without acquiring CSI.Based on the idea of Differential Spatial Modulation(DSM)in IM technology,two different IRS-assisted differential transmission schemes for wireless communication are proposed in this paper.On the one hand,this paper proposes a Differential RM aided SM(DRM-SM)scheme.In the DRM-SM scheme,this paper jointly maps the activation sequence of the reflection mode and the modulation symbols into information blocks.The information blocks are differentially encoded and transmitted,and each information block activates the same transmit antenna.From another perspective,this paper proposes a RM-DSM(RM aided DSM,RM-DSM)scheme.In the RM-DSM scheme,this paper jointly maps the transmit antenna activation sequence and modulation symbols into information blocks,and the differentially encoded information blocks are reflected by activating the same reflection mode.The simulation results show that these two schemes not only eliminate the limitations of IRS and CSI at the receiver,but also have their own advantages under different hardware conditions.