时变信道中自适应VR-HARQ研究

为了更好地解决时变信道中可靠性与吞吐率这一对矛盾,本文提出一种基于线性预测的自适应冗余可变混合ARQ(VR-HARQ)方案.在该方案中,由于时变信道的慢衰落特性,时变信道被等效为有限状态的Markov过程,每个Markov状态对应信道的不同信噪比,同时,文章详细地描述了信道吞吐率与误码率之间的数学关系,推导了每个Markov状态的最佳编码方案,然后系统采用自适应线性预测算法,根据当前个时段的信道状态,估计下一个时段信道的信噪比以及其所对应的Markov状态,最后根据吞吐率最大原则选择合适的纠错编码方案.仿真结果表明:自适应线性预测VR-HARQ方案的性能明显优于传统VR-HARQ方案.

An Adaptive VR-HARQ for Time-Varying Channels

For time-varying channel,the reliability of data transmission contradicts with the throughput efficiency.To solve the problem,the paper proposed a new VR-HARQ(Variable Redundancy Hybrid-ARQ) scheme based on the adaptive line predictor.Assumed that the fading of the time-varying channel is slow,the channel is equivalent to a finite-markov process,where each Markov state corresponds different BER.Simultaneity,the paper derives the best channel coding scheme for each Markov state.Based on the current time slot's channel states,the next time slot's channel state is predicted using adaptive line predictor algorithm.Then the best channel coding scheme is selected to maximize the channel throughput efficiency.Simulation results showed that the performance of the new scheme is better than that of the traditional schemes.