测向信息辅助的导频分配策略

Direction of Arrival Estimation Information-aided Pilot Allocation Strategy

多用户大规模多输入多输出(Multiple-Input Multiple-Output,MIMO)系统能够有效提升系统和速率,但是导频资源有限情况下,用户数增加时,非正交导频引起的导频污染会严重降低系统容量。针对导频资源不足引起的干扰问题,提出了用户测向信息辅助的导频分配策略。先介绍了用户到达角估计算法,分析了角度域信道与用户间非正交导频干扰之间的关系;再提出了一种角度域用户分组方法,并对用户导频进行优化,从角度域和导频空间两个维度降低用户间导频干扰,提高了系统和速率;最后,将信道估计归一化均方误差作为性能指标进行比较,以验证算法的有效性。仿真结果表明,该算法在导频资源受限的多用户场景中,能够有效减小用户间导频污染,验证了所提算法的有效性和可靠性。

The multi-user MIMO(Multi-Input Multiple-Output) system can effectively improve the system and speed. However, when the number of users increases with limited pilot resources, the interuser pilot pollution caused by non-orthogonal pilot can seriously reduce the system capacity. For the interference problem caused by insufficient pilot resources, this paper proposes a pilot frequency allocation strategy assisted by user direction finding information. First, the user arrival angle estimation algorithm is introduced, and the relationship between the angle domain channel and user non-orthogonal pilot interference is analyzed. Then, an angle domain user grouping method is proposed. On this basis, the user pilot is optimized, and a pilot allocation strategy based on the greedy criterion is proposed, which reduces the pilot interference between users from the angle domain and pilot space, and improves the system and speed. Finally, the normalized mean square error of channel estimation is defined as a performance index to verify the effectiveness of the proposed algorithm. Simulation results indicate that the proposed algorithm can effectively reduce pilot pollution among users in multi-user scenarios with limited pilot resources, which verifies the effectiveness and reliability of the proposed algorithm.