Full-Duplex opportunistic relay selection in future spectrum-sharing networks

Abstract

Abstract-We propose and analyze the performance of fullduplex relay selection in primary/secondary spectrum-sharing networks. Contrary to half-duplex relaying, full-duplex relaying (FDR) enables simultaneous listening/forwarding at the secondary relay, thereby allowing for a higher spectral efficiency. However, since the source and relay simultaneously transmit in FDR, their superimposed signal at the primary receiver should now satisfy the existing interference constraint which can considerably limit the secondary network throughput. In this regard, relay selection can offer an adequate solution to boost the secondary throughput while satisfying the imposed interference limit. We first analyze the performance of opportunistic relay selection among a cluster of full-duplex decode-and-forward relays with self-interference by deriving the exact cumulative distribution function of its endto-end signal-to-noise ratio. Second, we evaluate the end-to-end performance of relay selection with interference constraints due to the presence of a primary receiver. Finally, the presented exact theoretical findings are verified by numerical simulations.

Full-Duplex Relay Selection in Cognitive Underlay Networks

“…Despite its anticipated performance merits, the incorporation of relay selection techniques into cognitive FDR networks remained untackled to the best of the authors' knowledge till the work by the authors in [18]. In this work, we aim at bridging this gap by introducing relay selection to cognitive FDR networks and analyzing its offered performance gains.…”

“…While this work was in progress, preliminary results were accepted for presentation in IEEE ICC Wkshps'15[18] for the spectrum-sharing setting under Rayleigh fading, and in IEEE CAMAD'15[19] for the non-spectrumsharing setting under Nakagami-m fading. The currently presented work reports the full results for the spectrum-sharing setting under Nakagami-m fading which subsumes the results in[18] and[19] as special cases. Also presented is the diversity analysis of the FDRS protocols, as well as the relative performance to the half-duplex relay selection (HDRS) protocols.…”

Physical layer security enhancement in multi-user multi-full-duplex-relay networks

“…We also denote h n,n as the self-interference channel after imperfect self-interference cancellation. We assume that all channels experience block Rayleigh fading such that the channels remain constant over one block but vary independently from one block to another [15,16]. We denote P S and P R as the transmit power at S m and R n respectively.…”

On the performance of future full-duplex relay selection networks

“…This latter problem has been investigated in [16] in Rayleighfading environments where exact closed-form expressions were derived and validated.…”

“…More recently, the potential gains of relay selection have been independently investigated in [14], [15] and in [16], also within an underlay cognitive radio setting where a primary system imposes interference limitations that should be maintained. Specifically, the end-to-end signal-to-interference-plus-noise ratio (SINR) distribution has been derived in closed-form assuming no direct link exists under Rayleigh [14], [16] and Nakagami-m [15] fading. However, the performance analysis of the system becomes more challenging in the presence of a direct link.…”