基于分簇门限反馈的机会波束成形算法研究

Orthogonal Random Beamforming Based on Clustering and Feedback Threshold

在波束间存在干扰的小区通信场景中,研究满足反馈用户数约束条件时,如何有效运用机会波束成形(ORBF)算法实现和速率最大化的问题.针对该问题,提出了一种基于分簇门限反馈的ORBF算法.首先,将问题建模为基于反馈用户数约束的和速率最大化优化问题.然后,根据用户信噪比信息对小区内各用户进行分簇处理,并在各簇内利用极值理论工具独立设置反馈门限.最终,在分簇基础上构造出多门限反馈的ORBF算法.对算法性能进行理论分析,获得了和速率损失量上界的闭合表达式以及多用户分集增益的渐进形式.仿真实验验证了理论分析的正确性,同时表明,该算法与经典ORBF算法相比,能够在极大降低反馈量的同时取得很好的和速率性能.

This paper considers how to obtain the maximum sum-rates by using the orthogonal random beamforming （ORBF）technique under the constraint on the average number of feedback users in the context of facing inter-beam interfer-ence scenarios.Aiming to solve this problem,a novel ORBF algorithm based on clustering and feedback threshold is pro-posed.The users are divided into multiple clusters according to their SNRs.The corresponding feedback threshold in each cluster is calculated by the tool of extreme value theory.Finally,the new ORBF algorithm is constructed based on clustering and multiple thresholds.We make some theoretical analysis on the algorithm and derive the upper bound of sum-rates loss;the scaling law of multiuser diversity gain is also exhibited.Simulation results not only verify the validity of our analysis but also show that,when compared with the classical ORBF technique,the proposed algorithm can considerably reduce the feed-back load with a good sum-rates performance.