大规模MIMO下联合距离因子和用户优先级的导频分配方案

Pilot frequency allocation scheme for joint distance factor and user priority in massive MIMO

针对导频污染已成为大规模MIMO系统研究的最大阻碍问题,文中提出一种联合用户距离与用户优先级的导频分配方案来抑制导频污染。首先在只考虑第一层干扰的情况下,分别求出小区中距离小区基站不同距离用户的频谱效率,以小区中距离基站最近、频谱效率最大的用户作为基准,提出距离因子的定义,并给出表达式,此外,将各用户的距离因子和用户优先级结合进行导频分配研究。仿真结果表明,该方案能在保证频谱效率的前提下,有效减少正交导频数目。

The pilot frequency contamination has become the biggest obstacle to the research of the massive MIMO(multiple-input multiple-output) system. A pilot frequency allocation scheme combining user distance and user priority is proposed to suppress pilot frequency contamination. In the case where only the first layer interference is considered,the spectrum efficiency of users at different distances from the cell base station in the cell is derived. By taking the users who are closest to the base station and have the most spectral efficiency in the cell as the benchmarks,a determination and the expression of the distance factor are proposed. In addition,the distance factor of each user is combined with the user priority to research pilot frequency allocation. The simulation result shows that the scheme can effectively reduce the number of orthogonal pilot frequency under the premise of ensuring spectral efficiency.