Diversity-multiplexing tradeoff of coded cooperation with incremental relaying

This paper investigates the diversity-multiplexing tradeoff (DMT) performance of coded cooperation with incremental relaying (CCIR). First, the exact and closed-form DMT expression is derived for CCIR at arbitrary exchange ratio (ER), i.e., the ratio of the time duration of the first phase to that of the whole transmission phase. The result reveals that CCIR outperforms coded cooperation in terms of DMT. Compared with the slotted incremental decode-and-forward protocol, CCIR is more flexible in choosing ER, and performs better in DMT except for low multiplexing gain at high ER. Secondly, asymptotic power allocation, including both source and source-relay asymptotic power allocation, is carried out to improve the DMT performance under a long-term average power constraint. Finally, numerical results are provided to validate the analysis.