基站覆盖下D2D两跳传输的功率控制

设备到设备(D2D,device to device)技术是当今无线通信研究的关键技术之一.在单小区场景下引入了多跳D2D通信系统功率控制算法.在该场景下,多条D2D链路间通过复用频带来通信,同一D2D链路的用户采用两时隙的两跳解码转发中继(DF,Decode and forward)方式传输信息.不同链路两时隙之间非完全同步下,使用了同一频带的中继会相互干扰.作者提出的功率控制算法先引入松弛因子得到功率闭式解,通过迭代优化该问题中用户的发射功率,来减少中继间的同频干扰.最后,通过数值仿真证明,在D2D系统中加入该功率控制算法后,可一定程度上提升用户传输速率.正随着无线通信技术的发展,作为下一代无线通信系统中的重要组成Device to Device(D2D)通信系统,在LTE-A1]通信系统中引起了人们的广泛关注,D2D技术对基站负担增加不大的情况下,能够有效地提高通信速率.并且D2D通信系统的频谱分配较为灵活,既可使用小区的频段,又可以使用公共频段,如Wi MAX2]频段,进一步提高了系统的频谱利用率.在文献3-7]中,Klaus Doppler、Kaufman等人从不同角度提出了D2D建模方法和解决方案.文献

Distribute algorithm for two-hops Device-to-Device communications underlaying cellular networks

This paper proposed a power control algorithm for multi-hops device to device communication system under the single cellular networks.Different D2D links communicate by the shared band and users in one D2D links transmit message in two-hop Decode-and-forward mode.D2D users among different links which share the same band in asynchronous mode would get mutual interference.We use a proposal algorithm to approximate the optimistic solution with relaxation factor method,firstly get the closed expression of optimistic power,then we modify the transmission power to decrease the co-channel interference.At last,the simulation results verify the correctness of proposed power control algorithm and the improvement of system sum rate.