Location-based channel estimation and pilot assignment for massive MIMO systems

In this paper, a location-based channel estimation algorithm is proposed for massive multi-input multi-output (MIMO) systems. By utilizing the property of the steering vector, a fast Fourier transform (FFT)-based post-processing is introduced after the conventional pilot-aided channel estimation. Under the condition that different users with the same pilot sequence have non-overlapping angle-of-arrivals (AOAs), the proposed channel estimation algorithm is capable of distinguishing these users effectively. To cooperate with the location-based channel estimation, a pilot assignment algorithm is also proposed to ensure that the users in different cells using the same pilot sequence have different AOAs at base station. The simulation results demonstrate that the proposed scheme can reduce the inter-cell interference caused by the reuse of the pilot sequence and thus improves the overall system performance significantly.