Outage performance of two-way decode-and-forward relaying over block fading channels

In a two-way relaying (TWR) system, two nodes wish to exchange information with the help of relays. Previous work on TWR is mainly based on the assumption that the channel quality remains constant for one round of data exchange, however, the realistic channel fluctuates over time. In this paper, we study the outage behavior of a decode-and-forward (DF) TWR system over block fading channels where the channel condition may vary between two data transmission phases. Our results reveal that compared with constant-quality channels, the outage performance of the TWR-DF system deteriorates over block fading channels. The results also show that the influence of the change of relay locations on the outage probability over block fading channels is different from that over constant-quality channels. Additionally, the optimal relay location of reaching the minimum outage probability is not affected by the difference of channel quality between two data phases.