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In this paper, we focus on the problem of how to strike a balance between the QoS provisioning and the energy consumption when a cooperative communication scheme is applied in a clustered wireless sensor network. We characterize this tradeoff by a multi-variable optimization problem, with the goals of jointly maximizing the outage performance and the network lifetime. Then, we horizontally decompose...
Analytically studying the overall outage performance of two-way amplify-and-forward (AF) relaying systems has always been a difficult task. In this paper we study the overall outage probability (OOP) for the two-way amplify-and-forward (AF) relaying system. The channels are independent but not identically Nakagami-m fading distributed. We obtain the tight closed-form OOP approximated expression for...
In this paper, we investigate the outage behavior and throughput efficiency of a three-node cooperative ARQ system, which is equipped with a decode-and-forward relay node. We introduce four different cooperative ARQ protocols, followed by the analysis of their outage behavior and throughput efficiency under two different kinds of channel dynamics. We propose a general discrete time Markov chain model...
In a full frequency reused OFDMA system, inter-cell interference severely restricts the system's performance. Resource allocation, as an effective interference mitigation technique, is a key technique in the OFDMA system. In this paper, we investigate a novel resource allocation algorithm based on game theory. Firstly, available subcarriers are allocated according to the normalized channel gain. When...
Interference management is a key problem to system performance in the next-generation wireless networks. In this paper, a distributed cooperation policy selection scheme for interference minimization is proposed to perform subcarrier assignment for uplink multi-cell OFDMA systems by adopting a new solution concept, the correlated equilibrium, which achieves better performance by allowing each user...
In this paper, we analyze the performance of single relay selection cooperative wireless networks using decode-and-forward relaying. Under optimum relay selection, the uniform expressions for exact and asymptotic outage probability, average symbol error probability are derived in generalized fading channels. Then we improve the performance of the system through optimum power allocation based on asymptotic...
We consider the use of channel feedback to determine the pilot placement for channel estimation of two-way OFDM relay links. We propose a feedback technique in which the pilot allocation mechanism is adapted to the doubly-selective channels. The reduction in the SNR due to channel estimation error is considered by the criteria of SNR gap ratio, thus, is utilized to design the pilot placement. A suboptimal...
In this paper, we develop a distributed power control scheme for relay channels with confidential message in an uplink OFDMA-relay cellular by Amplify-and-Forward mode. We introduce a two-stage game in a progressive optimization. In this scenario, the relay is considered not only as a sender that assists the information transmission, but also as an eavesdropper who can wiretap information. In the...
In this paper, we propose a cognitive relay beamforming scheme to improve the throughput of primary user (PU), in which if a primary signal is not correctly received by the intended destination, a secondly user (SU) will be selected to retransmit it invisibly. Three issues are investigated in our work, i.e. beam weight design at SU, best-relay selection, and performance analyses. Firstly, by optimizing...
In this paper, the impact of channel state information (CSI) estimation errors on the performance of amplify-and-forward (AF) two-way relay network (TWRN) with single relay assisted has been investigated. The variance of channel estimation errors varies for different values of the transmitting SNR, dominated by the channel estimation quality order. We derive the exact closed-form and the approximate...
This paper focuses on the problem of selecting the optimal common node (CN) in a wireless sensor network to serve as the relay to aid the data transmission between the cluster head (CH) and the data fusion center (DFC). Optimal relay selection with the objective of minimizing the outage probability is a difficult problem which depends on multiple factors. In this paper, an outage-optimal relay selection...
Cooperative technology is one of the promising techniques to enhance the performance of wireless networks. In this paper, a cooperative MAC protocol with piggybacking (CPS-MAC) is designed for the WSN to improve the energy efficiency of the nodes' communication with each other. In this protocol, a relay node is selected basing on the buffer state and the channel state information (CSI) obtained by...
We consider the channel estimation for two-way relay OFDM networks. Aiming at time-varying characteristic of doubly-selective channels, we proposed an soft input Kalman channel estimator. To take advantage of soft information provided by the decoder, we combine this the Kalman filter with Turbo equalizer, so we needn't many pilot symbols in practice, still can ensure the algorithm performance and...
In this paper, we adopt the DMT framework to study a cooperative downlink OFDMA system with multiple relays. We derive the closed-form expression of the DMT curve for the cooperative OFDMA system employing linear constellation precoding at the base station, and linear detection at the mobile users, and develop the optimal symbol loading, relay selection and subcarrier allocation strategy. Simulation...
In this paper, we propose a hybrid cooperative scheme to improve the secrecy rate for a cooperative network in presence of multiple relays. Each relay node transmits a mixed signal consisting of weighted source signal and intentional noise. The problem of power allocation and joint design of beamforming and jamming weights are investigated, and an iterative solution for the secrecy rate maximization...
This paper studies the performance with partial relay selection in amplify-and-forward (AF) cooperative networks, where the relay node is selected depending on the instantaneous channel information of source-relay hop. The channels are independent but not identically distributed Rayleigh fading distributed. We obtain the exact outage probability expression and symbol error rate (SER) expression in...
Opportunistic relaying is an important relay selection scheme for cooperative communication, it can dynamically select relay depending on instantaneous channel condition, which is a especially suitable for distributed networks. Some cooperative MAC based on opportunistic relaying have been proposed to enhance the system throughput. However, since the throughput is normally related to their energy...
We analyze the impact of channel estimation errors on amplify-and-forward (AF) cooperative communication systems over Nakagami-m fading channels. We derive exact closed-form expression of the average symbol error rate (SER) with channel estimation errors by using the moment-generating function (MGF) based approach. Numerical results confirm that our theoretical analysis is very accurate.
In this paper, we study the secrecy communication using physical layer security in OFDMA networks. The expressions of secrecy rates and outage probability are derived in OFDMA networks using Decode-and-Forward (DF) strategy. Monte Carlo simulations are carried out to validate our analysis.
In this paper, a novel broadband ANC scheme is proposed for non-regenerative two-way relaying system with multiple relays under frequency-selective fading channel. The pair wise error probability is analyzed to investigate the achievable diversity gain. Theoretical analysis and simulation results both confirm that the new scheme can achieve both cooperative and multipath diversity and significantly...
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