Phase-Rotation-Aided Relay Selection in Two-Way Decode-and-Forward Relay Networks

Abstract

This paper proposes a relay selection scheme that aims to improve the end-to-end symbol error rate (SER) performance of a two-way relay network (TWRN). The TWRN consists of two single-antenna sources and multiple relays employing decode-and-forward (DF) protocol. It is shown that the SER performance is determined by the minimum decision distance (DD) observed in the TWRN. However, the minimum DD is likely to be made arbitrarily small by channel fading. To tackle this problem, a phase rotation (PR) aided relay selection (RS) scheme is proposed to enlarge the minium DD, which in turn improves the SER performance. The proposed PR based scheme rotates the phases of the transmitted symbols of one source and of the selected relay according to the channel state information, aiming for increasing all DDs to be above a desired bound. The lower bound is further optimized by using a MaxMin-RS criterion associated with the channel gains. It is demonstrated that the PR aided MaxMin-RS approach achieves full diversity gain and an improved array gain. Furthermore, compared with the existing DF based schemes, the proposed scheme allows more flexible relay antenna configurations.

Exact Outage Probability of Two-Way Decode-and-Forward NOMA Scheme with Opportunistic Relay Selection

“…Whereas the relays in the ANC only use two timeslots and simply amplify received data-carried signals of the sources in the first timeslot, then these sources decode the desired data from the amplified version at the remaining timeslot [26]. The authors in [27][28][29][30][31][32] researched the two-way DF relaying networks and analyzed the system performances in terms of bit error rate (BER) [27], symbol error rate (SER) [28], block-error-rate (BLER) [29], maximum achievable sum-rate [30], frame error rate [31] and (sum) outage probability [32]. Opportunistic relay selections have been considered in [31][32] with different operating conditions to achieve maximum end-to-end signal quality.…”

Performance analysis of two-way full-duplex relay with antenna selection under Nakagami channels

“…In more recent years, one-way DF relay considered with AS has also garnered a great deal of research interest. Lv and co-author investigated the max-min method for relay AS in two-way DF relay systems and proposed a single antenna system with receiver optimization [22,23]. Their approach can be implemented in a distributed manner without acquiring full channel state information (CSI) at the relay node.…”