Interference-limited Destination Research Articles

On the Symbol Error Rate and Diversity Gain Region of the Relay-Assisted Z-channel

Interference forwarding in a Z-channel makes interference stronger, which in turn enables usage of simple detectors like successive interference canceler (SIC) at interference-limited destination. In this work, the following protocols with SIC at the interference-limited destination are investigated: direct transmission ( $SIC_{Direct}$ ), half-duplex decode-and-forward ( $SIC_{DF}$ ), and half-duplex amplify-and-forward ( $SIC_{AF}$ ) protocols. The achievable diversity orders of these protocols using M-PAM and M-QAM modulation are obtained. Moreover, minimum required exponential orders of the average received signal powers at the relay and interference-limited destination to restore full diversity are presented. The $SIC_{AF}$ and $SIC_{DF}$ protocols are shown to achieve the same diversity order as that of the orthogonal transmission scheme while achieving better spectral efficiency than the orthogonal transmission. Closed-form expressions for the achievable diversity gain regions (DGRs) with the $SIC_{Direct}$ , $SIC_{DF}$ , and $SIC_{AF}$ protocols are derived. Selective decode-and-forward with SIC ( $SIC_{SDF}$ ) is also considered. The multiplexing gain regions and the interference levels where the $SIC_{AF}$ and $SIC_{SDF}$ protocols achieve better DGR than the $SIC_{Direct}$ protocol are obtained.

Performance Analysis of Amplify-and-Forward Relay Systems with Interference-Limited Destination in Various Rician Fading Channels

In this paper, we investigate the performance of a dual-hop fixed-gain amplify-and-forward relay system in the presence of co-channel interference at the destination node. Different fading scenarios for the desired user and interferers' channels are assumed in this study. We consider the Rician/Nakagami- $$m$$ m , the Rician/Rician, and the Nakagami- $$m$$ m /Rician fading environments. In our analysis, we derive accurate approximations for the outage probability and symbol error probability (SEP) of the considered scenarios. The generic independent non-identically distributed (i.n.d.) case of interferers' channels is considered for the Rician/Nakagami- $$m$$ m scenario; whereas, the independent identically distributed (i.i.d.) case is studied for the Rician/Rician and the Nakagami- $$m$$ m /Rician environments. Furthermore, to get more insights on the considered systems, high signal-to-noise ratio (SNR) asymptotic analysis of the outage probability and SEP is derived for special cases of the considered fading scenarios. Monte-Carlo simulations and numerical examples are presented in order to validate the analytical and asymptotic results and to illustrate the effect of interference and other system parameters on the system performance. Results show that the different fading models of interferers' channels have the same diversity order and that the interference degrades the system performance by only reducing the coding gain. Furthermore, findings show that the case where the fading parameter of the desired user first hop channel is better than that of the second hop gives better performance compared to the vise versa case, especially, at low SNR values; whereas, both cases almost behave the same at high SNR values where the performance of the system is dominated by the interference affecting the worst link. Finally, results show the big gap in system performance due to approximating the Rician fading distribution with the Nakagami- $$m$$ m distribution which is an indication on the inaccuracy of making such approximations in systems like the considered.

Relay Selection of Cooperative Diversity Networks With Interference-Limited Destination

We study relay selection in both decode-and-forward (DF)-based and amplify-and-forward (AF)-based cooperative diversity networks consisting of a source, multiple relays, and a destination in the presence of multiple interferers, where each terminal has a single antenna and operates in half-duplex mode. In the network, it is assumed that the multiple interferers locate near the destination and far away from relays; thus, only the destination receives interfering signals, which is referred to as the interference-limited destination. Specifically, we first propose relay selection to maximize the mutual information on cooperative networks with the interference-limited destination. Then, for relay selection of DF-based networks, we derive the exact outage probability. Finally, for relay selection of AF-based networks, we derive the exact outage probability in integral form and its closed-form lower bound.

Dual-hop systems with noisy relay and interference-limited destination

In this letter, we analyze the outage performance of a dual-hop relay fading channel in an interference-limited environment. We first derive closed-form expressions for the outage probability of both the amplify-and-forward (AF) and the decode-and-forward (DF) relay channels, based on which, the diversity analysis is conducted. In addition, we show that in terms of the outage probability performance, the worst scenario appears to be the case with equal received-power interferers, for a given total received interference power.