增强型正交调制协作系统及其功率分配

为了进一步提高正交调制系统的可靠性,引入了增量中继,提出一种增强型正交调制协作系统及其功率优化分配方案.首先分析了增强型正交调制协作系统传输过程的Markov状态转移图,求得该系统的Markov状态转移概率,进一步得到其误帧率的闭式近似解.然后给出一种低复杂度的准最优功率分配方案,以最小化系统误帧率为目标,通过迭代计算获得最优功率分配因子.仿真结果表明,与传统正交调制系统相比,增强型正交调制协作系统方案在4PAM的误帧率为10-2～10-4时性能最大可提升约4dB,采用准最优功率分配方案还能获得额外的约3dB性能增益.

Performance analysis and optimal power allocation for the incremental quadrature modulation cooperative system

In order to improve the reliability of the quadrature modulated(QM) cooperative diversity system,an incremental quadrature modulated(IQM) cooperative diversity system and its power allocation schemes are proposed,by introducing incremental relaying.Firstly,the system’s Markov states-transform probability is obtained through the analysis of the system’s Markov-process and then the closed approximate solution of the frame error rate(FER) is acquired.Finally,a quasi-optimized power allocation schemes(QOPA) with low complexity is presented.By minimizing the frame error rate(FER),the optimal power factors are obtained through iterative computation.Simulation result shows that the IQM system outperforms the traditional QM system by a maximum SNR benefit of 4 dB when the FER is in the range 10-4,10-2].Moreover,an additional 3 dB performance gain is obtained by adopting the QOPA schemes.