DMT for the Relay Assisted Interference Cancellation over Nakagami-m Fading Channel

In the present work, the diversity multiplexing tradeoff (DMT) for a decode-and-forward relay assisted two-user Z-channel with Nakagami-m fading is studied. In a two-user Z-channel, only one user is interference-limited while the other user is interference-free. Two transmission schemes, namely, common message only (CMO) and rate splitting (RS) schemes, are studied. In the CMO scheme, the interfering source uses single-user (SU) codes, and the interference-limited destination cancels the total interference. In the RS scheme, the interfering source uses multi-user (MU) codes, and the interference-limited user does partial interference cancellation. Closed-form expressions for the achievable DMTs with both the schemes are presented. The RS and the CMO schemes are shown to provide better DMT at the moderate and higher levels of interference, respectively.