3D MIMO多小区多用户系统基于QBFO算法的垂直波束下倾角优化

Downtilt Optimization Based on QBFO Algorithm with Vertical Beamforming for 3D MIMO Multi-Cell Multi-User Systems

本文针对大尺度衰落下3D MIMO多用户系统中天线下倾角优化问题,首先在采用最大比传输预编码的基础上,假设有用信号功率、用户间干扰功率、小区间干扰功率都服从伽玛分布,将系统和速率公式简化为关于波束下倾角的函数。然后,以系统和速率最大化为目标函数,利用改进的量子菌群觅食优化算法(quantum bacterial foraging algorithm),求解最优的天线下倾角。计算机仿真表明,本文提出的3D波束赋形方案在低信噪比和用户数较多时可以获得更高的系统和速率。

In this paper,we provide a scheme which can transform 3D beamforming into finding optimal antenna downtilt,specific to 3D multi-user MIMO Networks based on larger scale fading. First,we use Max Ratio Transmission（MRT） precoding. We assume desired signal power,inter-user interference power and inter-cell interference follow the Gamma distribution,then we can formulate an optimization to maximize system throughput in relation to antenna downtilt. Finally,we proposed an improved quantum bacterial foraging algorithm（QBFO） to find its solution. Simulation result shows that proposed scheme has higher achievable sum-rates compared with zero-forcing（ZF） precoders in lower SNR and better performance using QBFO.