在多用户同时同频发送信号的情况下, 由于每个用户的解调参考信号叠加在一起, 相互干扰, 所以精确估计出每个用户的信道冲激响应具有很大的难度。文章针对5G系统物理上行控制信道(PUCCH)的发送格式4, 利用不同用户的解调参考信号的特性, 设计了一种特殊的信号矩阵, 然后利用该信号矩阵, 结合传统的单用户信道估计算法, 提出了3种适用于5G系统PUCCH多用户复用情况下的信道估计算法, 包括基于最小二乘(LS)的样条插值算法, 基于LS的离散余弦变换(DCT)插值算法和基于线性最小均方误差(LMMSE)的DCT插值算法。最后对两个和4个用户的场景进行了仿真, 仿真结果表明, 所提的3种信道估计算法均适用于5G系统PUCCH的发送格式4, 对于工程中的应用具有很大的参考价值。

Since each user's demodulation reference signals are superimposed and interfere with each other in the case where multiple users simultaneously transmit signals at the same frequency, it is difficult to accurately estimate the channel impulse response for each user. In this paper, a special signal matrix is designed for the transmission format 4 of the 5G system Physical Uplink Control Channel (PUCCH) by using the characteristics of demodulation reference signals of different users. Then we combine this signal matrix with traditional single-user channel estimation algorithms to propose three channel estimation algorithms including Least Squares (LS)-based spline interpolation, LS-based Discrete Cosine Transform (DCT) interpolation algorithm, and Liner Minimum Mean Squared Error (LMMSE)-based DCT interpolation algorithm. Finally, the scenes of two users and four users are simulated. The simulation results show that three proposed channel estimation algorithms are applicable to the format 4 of 5G system PUCCH, which has great reference value for engineering applications.