In this paper, we investigate a resource allocation issue in OFDMA-based decode-and-forward cooperative multiuser networks and propose joint subcarrier and power allocation schemes. The optimal solution of this combinable allocation shows high computational complexity, so we allocate subcarriers and power separately. At firstly, we distribute subcarriers to relays and users under the assumption of equal power distribution. Here, we propose an equal capacity increment （ECI） allocation strategy to achieve tradeoff between total throughput and fairness. To further improve the system performance, we introduce threshold into ECI strategy, named ECI strategy with threshold （ECI-T）, where subcarriers with bad performance are prevented from transmitting. Subsequently, a water-filling method is adopted to distribute the power to cooperative links in order to fully utilize the limited power. Simulation results show that system performance of the proposed schemes is significantly enhanced compared with an existing resource allocation scheme. Besides, the resource allocation schemes with the water- filling method notably outperform schemes with equal power allocation.
不同于传统的采用固定码率编码的协作中继系统,在发送端不知道信道状态信息(channel state in formation,CSI)时,提出协作蜂窝系统下行链路中使用无限码率Raptor码及分布式空时分组码(distributed space-time block code,DSTBC)的新方案,并研究该方案有效性、可靠性和健壮性的问题。理论分析和仿真结果证明,当发送端不知道CSI时,结合应用Raptor码和DSTBC,即使在低信噪比(signal-to-noise ratio,SNR)环境中仍能降低总传输时间及能量消耗,给无线蜂窝系统带来显著的性能增益。
