Development of mathematical model for multi-user coded-cooperation based cognitive radio system and its outage probability analysis

In this paper, single and multi-user coded-cooperation based cognitive radio system is developed by designing its mathematical model where both source and relay will communicate to a single destination with the help of each other. Then all possible multi-user scenarios are developed and their end-to-end outage probability (Pout) is calculated for underlay mode of cognitive radio. The performance of the system is analyzed in the form of channel gain and interference temperature constraint for Rayleigh fading channel. The proposed system concludes that the coded cooperation with cognitive radio outperform the available techniques in the form of bandwidth, diversity, spectrum utilization efficiency and also improves the quality of communication. Furthermore, the theoretical analysis of the outage probability for both system models is validated by asymptotic analysis. The proposed system can set as a standard for all those cognitive radio applications which requires better spectrum efficiency even if there is a scarcity of multiple physical antennas.

Distributed Reed-Muller Coded-Cooperative Spatial Modulation

This paper proposes the distributed Reed-Muller coded spatial modulation (DRMC-SM) scheme based on Kronecker product (KP) construction. This special construction enabled an effective distribution of classical Reed-Muller (RM) code along source and relay nodes. The proposed DRMC-SM scheme not only offers robustness in bit error rate (BER) performance but also enhances the spectral efficiency due to additional antenna index transmission inculcated by spatial modulation (SM). The usefulness of KP construction over classical Plotkin (CP) construction in coded-cooperation is analysed with and without incorporating SM. An efficient criteria for selecting the optimum bits is adopted at relay node which eventually results in better weight distribution of mutually constructed (source and relay) RM code under proposed KP construction. The numerical results show that proposed KP construction outperforms CP construction by gain of 1 dB in signal to noise ratio (SNR) at bit error rate (BER) of 7 x 10 -7 . Moreover, the proposed DRMC-SM scheme outperforms its non-cooperative Reed-Muller coded spatial modulation (RMC-SM) scheme as well as distributed turbo coded spatial modulation (DTC-SM) scheme in similar conditions. This prominent gain in SNR is evident due to path diversity, efficient selection of bits at relay node and the joint soft-in-soft-out (SISO) RM decoder deployed at the destination node.