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Cooperative spectrum sensing by secondary user (SU) nodes in cognitive radio networks (CRNs) is a promising approach to increase the spectrum access efficiency and overall network performance. However, unreliable sensing results or malicious behaviors from cooperator SU nodes can be very disruptive and reduce the network performance. Trust and reputation modeling has been identified as one of the...
In this paper, the performance comparison of differential detection and coherent detection with imperfect channel estimation in AF cooperative communication is examined. We consider the real environment with channel estimation error, and utilize the average bit-error-rate (BER) performance of the two detection schemes to derive the BERs' crossover point between channel estimation error and signal-...
Cooperative relay networks have drawn more and more attention, since they can significantly improve network performance in terms of capacity and reliability. Multiple relay selection scheme is one of important issues which deserve careful design in such network. In this paper, we study the multiple relay selection (MRS) scheme in multiple parallel dual-hop Amplify-and-Forward relay networks, with...
We focus on the cooperative link scheduling problem and battery power attenuation in wireless sensor networks. Because recently a technical report on the development of battery has indicated that a linear attenuation can be maintained well. Therefore, linear function will be modeled to explore the influence of power attenuation in this paper, while four link scheduling strategies are considered. We...
Cooperative communications delivers spatial diversity for a communication system through the collaborated transmission of network users. Assisted by the intelligent relay selection, opportunistic cooperative communications in which the best relay is always selected for signal re-transmission can deliver a diversity gain on the order of number of relay candidates. It has the advantages of requiring...
In this paper, relay node deployment strategies are adopted into heterogeneous network scenario. The existence of cooperative relay nodes introduces more interference in the cellular domain. Firstly, we give the hetero-interference models which have great influence on heterogeneous access performance. Furthermore, outage probability and symbol error rate formula are derived under heterogeneous relay...
This paper presents a novel synchronization scheme for relay-assisted cooperative communication systems. According to the proposed scheme, the source node transmits a self-symmetric preamble. Taking advantage of this structure, the relay nodes carry out simple yet robust timing synchronization in the presence of large carrier frequency offset (CFO). Each relay node multiplies the received preamble...
In this paper, we analyze the outage probability of the multiple-relay cooperative networks with opportunistic relaying and incremental relaying (OIR) over independent but not identically distributed Nakagami-m fading channels. When the fading severity parameters (i.e., m) are integer, a lower bound on the outage probability is obtained, which is shown to be tight at high signal to noise ratio (SNR)...
The paper studied the outage performance for MIMO Multi-Relay ISDF (MR-ISDF) (Incremental and Selective Decode-and-Forward) cooperative communication systems. Firstly, the end-to-end mutual information, outage and OPA (optimal power allocation) for MR-ISDF was derived under the technology of MRC and beam-forming. Then the optimal single ISDF (OS-ISDF) which acted as routing protocol was introduced...
This paper addresses a joint radio resource allocation (RRA) and scheduling problem in a multi-cell OFDMA network in which the backhaul capacity is constrained. The proposed scheme is pursuing both the network utility and fairness among all users in two different levels, the intracell level and the intercell level. Analysis and simulation results suggest the proposed scheme brings better performance...
Inter cell interference is a severe problem in multi-cell OFDM systems. In this paper, an interference analysis based coordinated power allocation algorithm (CPA) is proposed. At the beginning of the strategy, each mobile station (MS) analyses its suffered interference, and judges the major interference source. Then, with the interference estimation information, the system can compute how to reallocate...
Cooperative communication system has emerged as a significant concept which improves reliability and throughput in wireless communication systems. Some existing cooperative diversity protocols have been shown to increase the diversity order, allowing single-antenna nodes to cooperate with each other and achieve high performance like a real MIMO system. In this paper, we focus on improving the precision...
In realistic cases, imperfect channel state information (CSI) occur either due to an imperfect channel estimation algorithm or due to fast changing channel. In this paper, we investigate the effect of channel estimation error on the linear minimum mean square error (LMMSE) receiver in amplify-and-forward (AF) relay systems. We derive the mathematical forms of the LMMSE receiver in the presence of...
In this paper, we consider a two-way relay network, where multiple pairs of users exchange their information with the help of a multi-antenna relay station by means of two-way relaying. A relay processing scheme based on minimum mean square error (MMSE) criterion is employed at the relay station to suppress inter- and intra-pair interference. We formulate the optimization problem of minimizing the...
This paper proposes a novel cooperative power allocation (PA) scheme for multi-cell cellular systems employing distributed precoding which is designed by maximizing virtual signal-to-interference-and-noise ratio (VSINR) to suppress inter-cell interference. The base stations (BS) from all the cooperated cells serve all users within these cells. Each base station is assumed to know only channel state...
Many resource partitioning and allocation schemes for OFDMA cellular system have been proposed to alleviate inter-cell Interference. However, majority of them focus primarily in frequency domain. In this paper, we consider sectored cells with fixed half-duplex FDD relay nodes in base coverage urban scenario. We study different inter-cell interference situations at first. Then we propose an adaptive...
In this paper, we investigate the closed loop extended orthogonal - space time block codes in decode-and-forward (DF) cooperative networks and propose an updatable Automatic Repeat reQuest (ARQ) protocol including relay selection. The relays correctly decoding the signals are incorporated into the relay set, and if there exist more than 4 relays in this set, we only choose 4 optimal relays based on...
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