To improve the resource utilisation of traditional two-way wireless relay system, an optimal power allocation (OPA) algorithm for a space-time cooperative network coding scheme employing amplify-and-forward protocol (...
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To improve the resource utilisation of traditional two-way wireless relay system, an optimal power allocation (OPA) algorithm for a space-time cooperative network coding scheme employing amplify-and-forward protocol (AF-ST-CNC) is proposed. The system performance in terms of outage probability and its approximation in high signal-to-noise (SNR) regimes are first derived, and with minimising the larger outage probability of the two sources, the optimal power factors are obtained by using an iterative algorithm. Moreover, the closed-form solutions of the optimal power allocation factor under some special scenarios are given. The proposed algorithm only needs the average channel gain information and has low computation complexity, which facilitates the practical implementation. Simulation results show that, the proposed AF-ST-CNC with OPA algorithm outperforms the AF-ST-CNC with equal power allocation (EPA) algorithm and the space-time cooperative network coding scheme employing amplify-and-forward protocol (DF-ST-CNC) with OPA algorithm in terms of outage performance and symbol error rate (SER) performance.
Automatic repeat-request (ARQ) protocols for two-user cooperative diversity system employing alamouti space-time coding are investigated in this paper. A whole cooperative transmit frame of an original cooperative sys...
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Automatic repeat-request (ARQ) protocols for two-user cooperative diversity system employing alamouti space-time coding are investigated in this paper. A whole cooperative transmit frame of an original cooperative system consists of three sub-frames. According to different feedback schedules in a transmit frame at the destination, two basic ARQ protocols, namely post-cooperating and pre-cooperating, are proposed and analyzed. We show that both proposed ARQ protocols can improve the throughput in two-user cooperative system. Pre-cooperating protocol yields 50% gains in users' throughput than post-cooperating protocol if both users have high user-destination average received signal-to-noise ratio (SNR) at the destination. Nevertheless, if both of user-destination average received SNRs are low, post-cooperating protocol is more effective than pre-cooperating protocol. Proposed protocols provide useful basic tools for designing more complicated ARQ protocols. Finally, simulation results verify our analysis. (C) 2009 Elsevier B.V. All rights reserved.
A random beamforming (RBF) technique is proposed to achieve omnidirectional coverage for broadcast channels in multiple-antenna systems. In the proposed scheme, the time and frequency resources for communication are d...
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A random beamforming (RBF) technique is proposed to achieve omnidirectional coverage for broadcast channels in multiple-antenna systems. In the proposed scheme, the time and frequency resources for communication are divided into many time-frequency blocks (TFBs). A random pattern is employed on each TFB, with the average power in all directions over many TFBs being equal. The design criteria and detailed design of the random pattern sequence are given. We propose a basic RBF scheme and an alamouti-enhanced scheme, as well as the corresponding structures of the transmitter and the receiver. Simulations are carried out for an eight-element unitary linear array with half-waveform separation in a fast-fading channel, showing that the proposed scheme greatly outperforms the cyclic delay diversity scheme and is robust to calibration errors and failures of radio-frequency chains.
In this paper, we investigate the outage probability performance of dual-hop alamouti transmission with channel estimation error in Rayleigh fading channels. The cumulative density function-based method is adopted to ...
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In this paper, we investigate the outage probability performance of dual-hop alamouti transmission with channel estimation error in Rayleigh fading channels. The cumulative density function-based method is adopted to obtain the outage probability expression in closed-form. Power allocation between the source and relay is also studied. Furthermore, asymptotic analysis is conducted to shed light on the diversity order. Finally, simulation results are presented to verify the analysis. Copyright (c) 2012 John Wiley & Sons, Ltd.
In this paper, the relay selection problem for two-way relaying networks in single and dual relay selection schemes is addressed. In the single relay selection scheme, the problem is to find the best relay node which ...
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In this paper, the relay selection problem for two-way relaying networks in single and dual relay selection schemes is addressed. In the single relay selection scheme, the problem is to find the best relay node which leads to the minimum bit error rate (BER) between the source nodes. We then derive the upper and lower bounds for the signal to noise ratio and the end-to-end BER of this scheme. In the dual relay selection scheme, the problem is to find the two best relay nodes. In this scheme, alamouti space-time coding and physical layer network coding are utilized in order to achieve the higher performance. For improving the system performance, optimal power allocation between the sources and the relays is considered based on decreasing the BER. Finally, simulation results are provided to verify the correctness of analytical results.
We investigate the error probability for alamoutispace-time coded orthogonal frequency-division multiplexing (OFDM) systems with carrier frequency offset (CFO) and multipath fading channels. Our main assumptions are:...
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ISBN:
(纸本)9781424492688
We investigate the error probability for alamoutispace-time coded orthogonal frequency-division multiplexing (OFDM) systems with carrier frequency offset (CFO) and multipath fading channels. Our main assumptions are: frequency-selective Rayleigh fading, a single receive antenna, and coherent detection. We derive new closed-form results for the (symbol or bit) error probability, for both spatially uncorrelated channels and spatially correlated channels. The proposed analysis shows that the error floor due to the CFO is strongly dependent on the power-delay profile of the multipath channel. Simulation results confirm the accuracy of the proposed theoretical analysis.
A random beamforming technique is proposed for broadcast channels in multiple antenna systems. In the proposed scheme, a random weight vector, corresponding to a random pattern, is imposed on each communication resour...
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ISBN:
(纸本)9781424483273
A random beamforming technique is proposed for broadcast channels in multiple antenna systems. In the proposed scheme, a random weight vector, corresponding to a random pattern, is imposed on each communication resource in time-frequency domain, with a resulting average of the random patterns on all resources to be isotropic. We proved that, the capacity of such a system is upper bounded by that of a single antenna system, on the premise of same power budget. The design criteria and detailed design of random patten sequence are presented. We propose a basic random beamforming and alamouti enhanced scheme, and a structure of the transmitter and receiver. The performance of the proposed scheme is verified by numerical simulation. It is also observed that it is robust to calibration errors and failures of radio frequency chains.
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