Down link: Performance of Cognitive MC-IDMA using Spatial Diversity and Polarization Diversity for Frequency Selective Channel

This article presents the simulation results of Multi Carrier (MC) interleave based accessing scheme named IDMA using spatial diversity and polarization diversity (PD) technique exploiting Cognitive spectrum sharing scheme. Here, space-time transmit diversity (STTD) structure is utilized as MIMO system by which we can exploit higher capacity in the multi-path environment. Cognitive spectrum band is designed for the users based on the availability and requirement and dual-polarized antenna is exploited to obtain PD that eliminates the problem of space constraint existing in Uni-Polarized antenna. The benefits of multi-carrier communication using IFFT algorithm is investigated to combat the effect of multi-path fading. For Multi-user signal transmission, we invoke IDMA by which we can derive better error-rate results with lower value Signalto-Noise ratio (SNR) while accommodating more-user population and we clearly expressed PD and STTD for MCIDMA system in realistic channel model specifications. From the performance curve, it can be deduced that MC-IDMA with cognitive spectrum offers superior bit-error rates while reducing channel deficiencies and giving larger bandwidth for individual users. Further, Dual-Polarized antenna structure overcome the space-constraint of mobile station while reflecting higher capacity using STBC coding.