Effective capacity of two way relay channels under retransmission schemes.

The important role provided by relays in communication networks is indisputable as they improve the transmission robustness by the retransmission schemes. In this paper, the effective capacity of two-way relay channels (TWRCs) in presence of retransmission schemes is investigated. We derive the effective capacity for the two phase scheme referred to as complex field network coding (CFNC). Based on the obtained results, we propose a hybrid scheme combining the traditional scheme (TS) and the CFNC, denoted by JTCNC. Automatic repeat request (ARQ) is used as the retransmission scheme, while the recent framework of the recurrence relation approach is adopted for the effective capacity. The asymmetric scenario, in which users may have different average signal to noise ratios (SNR) at the relay in the uplink and the downlink, is considered. Results obtained in this paper show that CFNC achieves the maximum value of R b/Hz/s at high SNR. However, it suffers from performance degradation when the uplink channel has low SNR. This problem is addressed in our proposed JTCNC scheme. The effective capacity for each user has also been derived and the impact of each source by the other sources is also investigated. [ABSTRACT FROM AUTHOR]