Cooperative Relaying in Underlay Cognitive Systems with TAS/MRC, Spatial Correlation and Hardware Impairments

The performance of an underlay cognitive (secondary) dual-hop relaying system with multiple antennas and hardware impairments at each transceiver is investigated. In particular, the outage probability of the end-to-end (e2e) communication is derived in closed-form, when transmit antenna selection with maximum ratio combining (TAS/MRC) is established in each hop. The practical scenario of spatial correlation among the antennas at the received signal is also considered. Simplified asymptotic outage expressions reveal some new useful engineering insights; namely the diversity and array order of the system, the balance on the number of transmit/receive antennas, and the impact of hardware impairments to the e2e communication.