On the Finite-SNR DMT of Two-Way AF Relaying with Imperfect CSI

A general framework of finite-SNR diversity-multiplexing tradeoff (DMT) is formulated to evaluate the impact of imperfect channel estimation in two-way amplify-and-forward (AF) relaying systems over Nakagami-m fading channels. Imperfect self-interference cancellation and signal detection are performed at both sources due to channel estimation errors. The overall outage probability (OOP) is obtained and then the finite-SNR DMT is derived in the presence of channel estimation errors. Furthermore, the asymptotic and limiting behavior expressions of the finite-SNR DMT are also evaluated adequately. Numerical results verify the theoretical analysis and show that at realistic SNR and channel estimation quality, the DMT is significantly lower than the asymptotic result.