关键词: 空时协作, 正交频分复用, 中断概率, 多径增益, 功率分配

Abstract:

In order to obtain a multi-path gain of orthogonal frequency division multiplexing （OFDM） in a space- time cooperative system, a space-time cooperative scheme based on the correlation of subcarriers in OFDM is pro- posed. In this scheme, by changing the order of the same signals in different phases of cooperative transmission, the signals are transmitted in two subearrier channels with the lowest correlation. Then, corresponding two-phase signals are combined together by the base station via a maximal ratio combing （MRC）. Moreover, the outage pro- bability is analyzed, and an optimal power allocation strategy is proposed. Finally, the theoretical bit error rate is analyzed. Simulated results demonstrate that the proposed scheme results in significant gains in bit error rate （BER） performance, and helps to obtain one-order multi-path gains without reducing the transmission rate.

Key words: space-time cooperation, orthogonal frequency division multiplexing, outage probability, multi-path gain, power allocation