  This paper explores the secrecy performance of a multi-transmitter system
with unreliable backhaul links. To improve secrecy, we propose a novel
transmitter selection (TS) scheme that selects a transmitter with the maximum
ratio of the destination channel power gain to the eavesdropping channel power
gain. The backhaul reliability factor is incorporated with the distribution of
the channel power gain through the utilization of a mixture distribution. We
evaluate the non-zero secrecy rate (NZR) and the secrecy outage probability
(SOP) as well as their asymptotes in two scenarios of backhaul activity
knowledge, where it is available and where it is unavailable. The results
illustrate that because of the unreliable backhaul, the proposed
destination-to-eavesdropper channel power gain ratio-based TS scheme is
constrained in terms of secrecy performance. However, performance enhancements
are observed when the backhaul knowledge activity is utilized. Furthermore, the
proposed scheme outperforms all the sub-optimal TS schemes and achieves nearly
optimal performance without requiring noise power or the evaluation of the
exact secrecy rate measurement.
