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| On Power Allocation for Alamouti STBC-OFDM Systems with Distributed Transmit Antennas in the Presence of Residual Frequency Offsets |
| Sun Ke Tang You-xi Shao Shi-hai |
| National key Lab. of Science and Technology on Communications, University of Electronic Science and Technology of China, Chengdu 611731, China |
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Abstract In this paper, a transmit power allocation method is proposed for distributed transmit antenna Alamouti Space-Time Block Coded Orthogonal Frequency Division Multiplexing (STBC-OFDM) systems based on Cholesky-decision-feedback detector in multipath Rayleigh fading channels with multiple Residual Frequency Offsets (RFOs). The method is designed by minimizing the lower bound of the average Bit Error Ratio (BER) so as to reduce the influence of RFOs. Theoretical analysis of the lower bound on the average BER performance is presented and the closed-form expression of the optimal power allocation factor is derived. Simulation results show that in the scenario where the performance is dominated by the RFOs, the proposed method provides increasing performance gain compared with the conventional power allocation method ignoring the existence of RFOs as the ratio between the average channel gains from the two transmit antennas to receiver increasing.
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Received: 01 September 2009
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Corresponding Authors:
Tang You-Xi
E-mail: tangyx@uestc.edu.cn
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2010, Vol. 32 
