Performance Analysis of a Multi-Hop UCRN With Co-Channel Interference

In this paper, the performance of a multi-hop underlay cognitive radio network (UCRN) is thoroughly assessed. The co-existence of a primary transceiver and co-channel interference (CCI) is considered along with an uplink single-input multiple-output system utilizing selection combining and maximal ratio combining techniques at the receiver nodes. First, the equivalent per-hop signal-to-interference-plus-noise ratio (SINR) for the UCRN is formulated. Second, the exact cumulative distribution function (CDF) and the probability distribution function of the per-hop SINR are derived and discussed. Furthermore, approximate expressions exhibiting reduced complexity for the per hop equivalent CDF are derived to provide more insights. From the resulting CDF, the exact outage performance of the CR network is thoroughly assessed. In addition, mathematical formulas are derived for the average error probability and system ergodic capacity. Finally, the derived analytical expressions are validated by presenting numerical and simulation results for different network parameters. The results show that several factors contribute to the degradation of the system performance, namely, the interference power constraint, the primary transmitter power, and the presence of CCI, especially in the case where the CCI increases linearly with the secondary transmission powers.