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．     

联合正交调制与网络编码的协作HARQ方案

为了提高正交调制协作系统的传输效率,提出联合网络编码与正交调制协作混合自动重传请求方案。所提方案在重传中引入了网络编码,使得系统可以在相同的时间内能够重传更多的信息,从而节约了重传时间,进而改善系统吞吐量。接着,建立了Markov状态转移模型,并推导了所提方案在各种脉冲幅度调制(PAM)方式下的误帧率和延时性能,进而获得其吞吐量闭式近似解。仿真结果表明,与传统正交调制协作HARQ方案相比,所提方案在信噪比为5 dB、10 dB、15 dB处分别采用2PAM、4PAM、8PAM调制时都有近8%的吞吐量增益。     

Energy efficiency enhancement of two-way amplifier forward relaying with channel estimation error简

In order to save energy consumption of two-way amplifier forward （AF） relaying with channel estimation error, an energy efficiency enhancement scheme is proposed in this work. Firstly, through the analysis of two-way AF relaying mode with channel estimation error, the resultant instantaneous SNRs at end nodes is obtained. Then, by using a high SNR approximation, outage possibility is acquired and its simple closed-form expression is represented. Specially, for using the energy resource more efficiently, a low-complexity power allocation and transmission mode selection policy is proposed to enhance the energy efficiency of two-way AF relay system. Finally, relay priority region is identified in which cooperative diversity energy gain can be achieved. The computer simulations are presented to verify our analytical results, indicating that the proposed policy outperforms direct transmission by an energy gain of 3 dB at the relative channel estimation error less than 0.001. The results also show that the two-way AF relaying transmission loses the two-way AF relaying transmission loses its superiority to direct transmission in terms of energy efficiency when channel estimation error reaches 0.03.     

增强型编码双向中继方案及中断概率分析

 该文提出了一种基于网络编码和空时协作的增强型双向中继方案。根据系统各节点的反馈,该方案将网络编码和空时协作有机结合,能提高系统资源利用率和网络吞吐量。推导了所提方案及现有的两种双向中继方案的中断概率,并分析了各方案在快衰落和慢衰落信道下的分集增益和网络编码增益。结果表明：相对于其它两种方案,所提方案在快衰落信道下,可获得三阶的分集增益;在慢衰落信道下,也可获得更高的编码增益。最后通过仿真验证了分析结果的正确性。