多蜂窝系统下行多用户CoMP中一种次优的子载波和功率分配算法

针对传统的协作多点传输/接收(CoMP)系统中蜂窝中心用户和边缘用户在子载波分配过程中出现的分配不公平和未考虑可变功率因素的问题,提出了一种次优的旨在最大化扇区内所有用户吞吐量的子载波和功率分配算法.该算法将蜂窝边缘用户可使用的频率资源扩展到蜂窝所在的整个频段,同时蜂窝中心用户和边缘用户在整个频段上通过正比公平算法竞争最优的子载波资源,用以保证用户的公平性,然后根据最优化目标函数和得到的子载波分配算法,对小区内的所有用户进行最小速率和正比公平限制,利用拉格朗日乘子法计算出了分配给每个用户的功率.仿真结果显示,该算法可以显著提高所有用户的公平性和吞吐量.

A Sub-Optimal Sub-Carrier and Power Allocation for the Downlink Multi-User CoMP in Multi-Cell Systems

In traditional sub-carrier allocation algorithms,the problem of unfairness between the cell-edge users and cell-center users and varying power allocation in downlink coordinated multiple point transmission/reception(CoMP) system is ignored.To solve this problem,a sub-optimal sub-carrier and power allocation algorithm to maximize all the users’ throughput in one sector is proposed.In this algorithm,the frequency bandwidth that the cell-edge users can occupy is extended to the whole frequency bandwidth that the BS(base station) assigns to the cell,the cell-center users and cell-edge users compete for the optimal sub-carrier through the proportional fairness algorithm which will ensure the fairness.Then according to the optimization objective function and the proposed sub-carrier allocation algorithm,the minimum rate and the proportional fairness constraint are introduced in connection to all the users.At last,the power allocated to each user is calculated using the Lagrange multiplier method.Simulations show that this algorithm will improve all the users’ fairness and throughput obviously.