低复杂度大规模MIMO系统上行功率分配算法

Lowcomplexity power allocation algorithms for uplink of massive MIMO systems

为了降低莱斯信道衰落下多小区大规模多输入多输出系统上行链路功率分配算法的复杂度,提出了基于小区近似和速率的低复杂度功率分配算法.首先,给出基站采用最大比合并接收时的小区和速率近似表达式及其上下界;然后,在小区发射总功率受限及保证用户服务质量需求的条件下,提出分别基于上、下界的2种功率分配算法.这2种算法仅利用大尺度衰落等长时信道信息,减少了信道估计开销及运行功率分配算法的次数,从而降低了系统实现复杂度.仿真结果表明,与等功率分配算法相比,所提算法在低信噪比下能够显著提升系统和速率;然而,信噪比越大,性能增益越小.因此,这种新的功率分配算法可以有效应用于低信噪比情况.

In order to reduce the complexity of the power allocation algorithm for the multi-cell massive multiple-input multiple-output（ MIMO） systems in Ricean fading channels,lowcomplexity power allocation algorithms based on the uplink sum rate are proposed. First,in the case of using the maximal-ratio combing（ MRC） receiver,an approximate expression of the uplink sum rate and its lower and upper bounds are presented. Then,two power allocation algorithms based on lower and upper bounds respectively are put forward,which satisfies that the total power transmitted by all users is limit and the quality of service of every user is met. These two algorithms only utilizing the long term channel state information such as large-scale fading can reduce the channel estimation overhead and times to perform the power allocation schemes,inducing the reduce of the complexity of system implementation. The simulation results showthat,compared with the equal power allocation algorithms,the proposed power allocation algorithms can improve the sum rate significantly with the lowsignal to noise ratio. However,the higher the signal to noise ratio,the smaller the performance gain. Therefore,the proposed power allocation algorithms can be effectively utilized in the situations with lowsignal to noise ratio.