Suneel Yadav

Performance Evaluation and Optimization of Traffic-Aware Cellular Multiuser Two-Way Relay Networks Over Nakagami- m Fading

We consider a cellular multiuser two-way relay network, where a multiantenna base station communicates with one of the several single-antenna mobile stations via a single-antenna relay terminal. We derive the exact and asymptotic overall outage probability (OOP) expressions of the considered system with asymmetric traffic under Nakagami-m fading. Based on the asymptotic analysis, we formulate three optimization problems, namely, optimal power allocation (OPA) with fixed relay location, optimal relay location with fixed power allocation, and jointly OPA and relay location to minimize the OOP. Specifically, we investigate two OPA schemes, called OPA I and OPA II. To this end, OPA I provides the solutions for individual transmit powers at each terminal, whereas under OPA II, relay terminal is assigned with half of the total power and the remaining power is allocated to the end terminals. The numerical and simulation results corroborate our theoretical findings, and reveal that under highly asymmetric traffic, OPA I can achieve a significant OOP performance than OPA II for different relay locations, except at the relay location where both coincide. Under symmetric traffic, OPA I outperforms OPA II, irrespective of relay locations. The OOP performance can be further improved if the power allocation and relay location are jointly optimized, especially under unbalanced conditions.

Antenna selection with user scheduling in traffic-aware cellular two-way relay networks

We investigate the outage performance of a cellular multiuser two-way relaying networks (TWRNs), where a multi-antenna base station (BS) communicates with one of the several single-antenna mobile stations (MSs) via a single-antenna relay terminal. We employ antenna selection at BS coupled with MS selection to maximize the end-to-end signal-to-noise ratio (SNR). In view of asymmetric traffic requirements at the end terminals, we derive the tight closed-form overall outage probability (OOP) expression of the considered system under Rayleigh fading. We also derive an asymptotic outage behavior in high SNR regime to reveal the impact of asymmetric traffic and system parameters on the achievable diversity order. Moreover, we formulate an optimization problem of relay location to minimize the OOP of the considered system. Numerical and simulation results corroborate our theoretical analysis and findings, and also demonstrate that the optimal relay location has a significant impact on the OOP performance under asymmetric traffic demands.

Joint Impact of Co-Channel Interference and Channel Estimation Error on Outage Performance of Cellular Two-Way Relay Networks

This paper investigates the joint impact of co-channel interference and channel estimation error (CEE) on the performance of cellular multiuser two-way relay network, wherein a multi-antenna base station communicates with one of the several single-antenna mobile stations via a single-antenna relay. Specifically, we derive a tight lower bound closed-form expression for the overall outage probability under Rayleigh fading channels. We also evaluate an asymptotic outage expression in the high signal-to-noise ratio regime. Based on the asymptotic analysis, we study some practical cases of interest under both interference-limited and interference-free scenarios with CEE, from which various insights into the system diversity order are presented. Numerical and simulation results corroborate our theoretical findings.

Ergodic Sum Rate Evaluation of Cellular Multiuser Two-Way Relaying with Beamforming and Antenna Selection Over Nakagami-m Fading

In this paper, we evaluate the ergodic sum rate (ESR) performance of cellular multiuser two-way relaying networks (CMTWRNs), where a multiantenna base station (BS) exchanges information bidirectionally with one of the several single-antenna mobile stations (MSs) with the help of a single-antenna relay terminal. Specifically, we adopt two transmission schemes (i.e., beamforming (BF) and antenna selection (AS)) at the BS and user selection at MSs to maximize the end-to-end signal-to-noise ratios. Under such transmission schemes, we derive new tight closed-form ESR expressions for the CMTWRNs in the presence of Nakagami-m fading environment. Further, based on the numerical results, we conduct a comparative study between the ESR performances of the two schemes, which indicates that the AS scheme provides approximately equal ESR performance as BF. Therefore, AS scheme can be a good alternative to the BF for the CMTWRNs as it reduces the transceiver complexity and signaling cost. Finally, simulation results are presented to corroborate our theoretical findings.

Performance analysis of incremental hybrid decode-amplify-forward cooperative relaying with relay selection in Nakagami- m fading channels

Abstract In this paper, we investigate the performance of incremental hybrid decode-amplify-forward relaying (IHDAF) protocol for the dual-hop cooperative multi-relay networks. We deduce a tight closed-form expression for the outage probability (OP) by employing opportunistic relay selection (ORS) under Nakagami- m fading channels. We further derive an asymptotic outage expression in the high signal-to-noise ratio (SNR) regime, from which the diversity order is examined. Based on the asymptotic results, we also present an optimal relay location to minimize the overall system outage. In addition, we derive new tight closed-form expressions of ergodic capacity and asymptotic ergodic capacity for the considered system. Finally, numerical and simulation results show the correctness of our analytical findings and the performance enhancement of the considered system with ORS-IHDAF scheme compared with the other incremental ORS-based cooperative schemes.