Performance analysis of full duplex relaying in vehicular cooperative wireless communications

Abstract

Vehicular communications, with their promise to provide drivers and passengers with a wide range of applications such as vehicle parking, accident response and traffic congestion avoidance are attracting significant attention from both research and industry. In addition V2V cooperative wireless networks could be used to share and exchange information between vehicles and also to provide a high data rate for functions like video streaming. Vehicular Ad-Hoc NETworks (VANETs) have received significant attention in recent years due to their unique characteristics that distinguish them from Mobile Ad-Hoc NETworks (MANETs), including link failure, rapid topology change and high mobility that form a highly dynamic network. The main drawback of VANETs is the network instability, which reduces network efficiency. In light of the aforementioned characteristics, vehicle-to-vehicle (V2V) cooperative wireless communications can be a reliable solution for these networks. V2V wireless cooperation systems make use of better communication links between users to improve system performance in terms of communication reliability, road safety, and network connectivity. V2V cooperative wireless communications can also offer diversity, which increases the reliability by sending information via different paths, thereby increasing the probability of successful transmission. Therefore, in this work, we provide a comprehensive performance analysis of full duplex AF V2V cooperative wireless networks that help researchers for the design and implementation of vehicular communication systems. Specifically, we first investigate full duplex relaying (FDR) networks applying amplify-andforward (AF) relaying in V2V cooperative communications. In this context, taking into account the self-interference (SI) at the relay and assuming independent but not necessarily identically distributed (i.n.i.d) generalized L-Nakagami m fading channels, we derive novel expressions for the probability density function (PDF) and cumulative distribution function (CDF) of the signal-to interference-plus-noise ratio (SINR) at the relay node. Capitalizing on this, a lower bound of the end-to-end outage probability is derived. The results show that the channel cascading, which has been shown to accurately characterize the statistical properties of V2V fading channels, significantly impacts the end-to-end outage probability of FDR V2V systems, and that the cascading of the source-relay link is more significant than the relay destination link. Second, we explore the performance of FDR using AF technique in V2V cooperative wireless communications. In such systems, in practical scenarios, the communication link inevitably suffers from co-channel interference (CCI), SI, and blockage from other vehicles on the road. In this context, we consider i.n.i.d Nakagami-m fading channels and derive novel exact and asymptotic outage probabilities of the exact equivalent and approximated SINR respectively. Moreover, the end-to-end exact and asymptotic outage probabilities are expressed in terms of the blockage probability and then used to evaluate the throughput of the proposed system. In addition, a lower bound to the symbol error rate of the considered system is also derived. The results show the significant impact of the considered interference and blockage on the system performance. Also, the results establish that the outage probability, symbol error rate, and throughput are degraded when the average height of the obstacles is increased. Third, we analyze the ergodic capacity of a dual-hop AF FDR system over Nakagami-m fading channels considering both SI and CCI at the relay and the destination nodes, respectively. For this scheme, new exact as well as lower bound expressions for the ergodic capacity are derived based on the analysis of the moment generating function (MGF) of the SINR. In addition, the ergodic capacity upper bound is derived based on the asymptotic outage probability of the approximated SINR. Our results show the significant impact of the considered interferences on the system performance. Moreover, interestingly, it is observed that FDR with SI and CCI still offers higher ergodic capacity than interference-free half duplex relaying, especially at medium and high signal-to-noise ratios (SNRs). Finally, we present a best vehicular relay selection strategy for FDR V2V communication systems in a dense multi-lane highway. The proposed model assumes Nakagami-m fading channels in millimeter-wave (mmWave) networks and proposes two different FDR selection schemes such as self-interference (SI) and individual self-interference (ISI) vehicle relaying selections. Moreover, a blockage probability which captures the occurrences of line-of sight (LOS) and non-line-of-sight (NLOS) propagations is devised. In this vein, a LOS link is considered available when the central lane is clear of vehicles between the source and destination nodes, while an NLOS link is assumed otherwise. The LOS/NLOS probabilities are combined together with the probability of blockage and then used to analyze the system performance. Moreover, lower bound expressions of the end-to-end outage probabilities are developed and used to express the throughput. Lastly, the theoretical results postulated and presented in this work are verified by numerical simulation for a variety of parameters.

Date	23 Jun 2020
Original language	American English
Awarding Institution	École de technologie supérieure
Supervisor	Georges Kaddoum (Supervisor)