A Survey on Cooperative Diversity for Wireless Networks

Article (PDF Available)inIEEE Communications Surveys & Tutorials 14(99):1 - 14 · January 2012with202 Reads
DOI: 10.1109/SURV.2011.082611.00047 · Source: IEEE Xplore
Abstract
Diversity, i.e. transmitting multiple replicas of a signal, may mitigate fading in wireless networks. Among other diversity techniques, the space diversity of multi-antenna systems is particularly interesting since it can complement other forms of diversity. The recent cooperative diversity paradigm brings the advantages of multi-antenna space diversity to single antenna networked devices, which, through cooperation and antenna sharing, form virtual antenna arrays. However, cooperative diversity is a complex technique and research on this topic is still in its early stages. This paper aims at providing a general survey on the theoretical framework; and the physical and medium access control proposals in the literature.
    • "There are some survey contributions which address different techniques of cooperation in wireless networks. In [24], the authors presented a general survey on the theoretical framework and existing PHY and MAC proposals in the literature works. In the next survey [31], the main focus is on the contention-based MAC protocols and a classification of these protocols were presented according to fundamental issues of " when to cooperation " and " whom to cooperate " . "
    [Show abstract] [Hide abstract] ABSTRACT: The concept of cooperative communication appears as a beneficial method that can address key challenges faced by wireless networks. Cooperative techniques in IEEE 802.11 MAC protocols have thus received significant attention both in theoretical and practical aspects. In this survey article, we provide an overview of existing research on cooperative MAC protocols in the IEEE 802.11 standard. We specially focus on protocol’s behavior and propose a novel architectural model for cooperation. We present a classification of cooperative relay based MAC protocols, along model desired categories, and review representative cooperative protocols for 802.11. We further evaluate the operational issues of cooperative protocols in term of architecture, compatibility and complexity.
    Full-text · Article · Oct 2016
    • "On the other hand, in DnF systems, single or multiple relays decode, re-encode, and forward the outcome to the destination. In multi-relay cooperative systems, single relay selection (SRS) is of importance for practical implementation because it not only reduces the system complexity but also improves the system spectral efficiency while maintaining the system diversity order (DO) compared to schemes exploiting all available relays, i.e., orthogonal transmission, distributed space-time coding, and distributed beamforming schemes [2]. SRS investigated in existing literature can be categorized as best relay selection (BRS) and partial relay selection (PRS) [3][4][5][6]. "
    [Show abstract] [Hide abstract] ABSTRACT: In this paper, we consider amplify-and-forward (AnF) cooperative systems under correlated fading environments. We first present a brief overview of existing works on the effect of channel correlations on the system performance. We then focus on our main contribution which is analyzing the outage probability of a multi-AnF-relay system with the best relay selection (BRS) scheme under a condition that two channels of each relay, source-relay and relay-destination channels, are correlated. Using lower and upper bounds on the end-to-end received signal-to-noise ratio (SNR) at the destination, we derive corresponding upper and lower bounds on the system outage probability. We prove that the system can achieve a diversity order (DO) equal to the number of relays. In addition, and importantly, we show that the considered correlation form has a constructive effect on the system performance. In other words, the larger the correlation coefficient, the better system performance. Our analytic results are corroborated by extensive Monte-Carlo simulations.
    Full-text · Article · Sep 2016
    • "Wang). formance with smaller transmission power [3][4][5][6], which essentially decreases the interference imposed on other users. This concept is equivalent to vacating hidden spectrum resources for users in its neighborhood area. "
    [Show abstract] [Hide abstract] ABSTRACT: In underlay relay-based cognitive radio networks, when the interference imposed on primary users is below some pre-determined threshold, secondary users can use the licensed spectrum although it is occupied by primary users. Hence, energy-efficient power allocation among secondary users and cognitive relay is one of the key techniques to utilize this new network paradigm effectively as power is the key component of the interference imposed on primary users. In this paper, for cognitive radio cooperative communication (CRCC) networks where multiple secondary users share a common cognitive relay with amplify-and-forward (AF) mode, we propose an optimal power allocation strategy with the objective to minimize the sum-power consumption of the system. In addition to the constraints that restrict the interference on the primary users within pre-determined threshold, the formulated problem has constraints to ensure the minimum SNR achieved by secondary users and the cognitive relay has a total power constraint. From the inner understanding of the problem, we simplify the formulation. In order to transform the problem to a search problem of finding equilibrium points of power allocation, a theorem is proposed which provides the condition for sum-system-power minimization state. Consequently, an algorithm with linear time complexity is developed based on that theorem. Extensive simulation has been conducted under different system setups to justify the effectiveness and efficacy of our power allocation strategy comparing with other methods usually adopted to solve this type of problem.
    Full-text · Article · Apr 2016
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