Combined Effect of RF Impairment and CEE on the Performance of Dual-Hop Fixed-Gain AF Relaying

We study the performance of dual-hop fixed-gain (FG) amplify-and-forward (AF) relaying systems in the presence of both radio frequency impairments (RFI) and channel estimation error (CEE). The expression for end-to-end signal-to-noise plus distortion-and-error ratio is derived along with exact analytical expressions of outage probability (OP) over independent but non-identically distributed Nakagami-m(i) fading channel. Then, we perform an asymptotic analysis of OP at high SNR and find that there is an error floor on OP due to the effects of CEE. Although there is no direct effect of RFI on the error floor, the way in which it affects the value of CEE at high SNR and thus takes part in indirectly elevating the error floor is also looked into. The analytical results are validated through Monte Carlo simulation. Finally, the dominance of RFI and CEE at different transmission rates and average SNRs is also discussed.