无线携能OFDM中继系统的联合资源分配研究

Joint Resource Allocation in SWIPT OFDM Relay Systems

在能量受限的中继系统中,无线携能通信技术是一种有效地延长其使用寿命的方法.本文研究具有大规模天线阵列结构的正交频分复用(OFDM)解码转发中继系统的无线携能通信,其发送端配备了大规模天线阵列.传输过程分为3个时隙,在第一个时隙,发送端运用基于最大比传输的波束成形向中继传输能量;在第二个时隙,发送端向中继发送信息;在第三个时隙,中继使用之前收获的能量向接收端转发信息.讨论了信息和能量传输的功率在各子载波间的分配以及3个时隙的时长分配问题,提出了一种最大化传输信息速率的时间和功率联合分配最优算法.仿真结果表明,该算法明显优于已有功率和时间分配算法.

Simultaneous wireless information and power transfer(SWIPT) is an effective way to prolong the operation time of energy-constrained wireless relay systems. A large-scale antenna array based SWIPT orthogonal frequency division multiplexing(OFDM) decode and forward(DF) relay system, in which the source is equipped with large-scale antenna array, is considered. The transmission process is divided into three time-slots. In the first time-slot, the source transmits power to the relay using maximum ratio transmission beamforming; in the second time-slot, the source transmits information to the relay; in the third time-slots, the relay transmits the information to the destination using the harvested energy in the first time-slot. Both the power allocation(PA) over the sub-carriers for information and power transmissions from the source to the relay and from the relay to the destination, and the time allocation(TA) between the first, second and third time-slots are investigated. An optimal joint PA and TA algorithm has been proposed. Computer simulation results shows that the proposed algorithm outperforms some benchmark schemes.