OFDM channel state information (CSI) is needed for determining key parameters in MIMO transmissions. In this paper, a novel CSI estimation method, ParEst, is proposed, which estimates the CSI from multiple transmitting antennas simultaneously. ParEst is based on a recent discovery that the CSI can be approximated very well by the linear combination of complex-based sinusoids on constant frequencies. ParEst finds the CSI of all antennas jointly by solving an optimization problem and achieves higher accuracy than existing heuristic methods. As the base sinusoids are on constant frequencies, ParEst pre-computes most key steps and reduces the run-time computation complexity to just a modest number of vector dot products equivalent to a few FFT calculations. ParEst can be applied to MIMO links in networks such as LTE, 5G, or Wi-Fi.

需要OFDM信道状态信息（CSI）来确定MIMO传输中的关键参数。本文提出了一种新颖的CSI估计方法ParEst，它可以同时估计多个发射天线的CSI。ParEst基于最近的发现，即通过基于复数的正弦波在恒定频率上的线性组合，CSI可以很好地近似。通过解决优化问题，ParEst共同找到了所有天线的CSI，并且比现有的启发式方法具有更高的精度。由于基本正弦波的频率恒定，因此ParEst可以预先计算大多数关键步骤，并将运行时的计算复杂度降低到仅适量的矢量点乘积，这等效于一些FFT计算。ParEst可以应用于LTE，5G或Wi-Fi等网络中的MIMO链路。