Robust Angle of Arrival Estimation in Multi UE Transmission

Angle of Arrival (AoA) estimation is the method used to determine the direction from which a received signal arrives by analysing the signal that reaches an antenna array. Accurately estimating the AoA of the line-of-sight (LOS) path is crucial for various applications, including determining the precise location of a wireless device. This paper provides an exploration of AoA estimation techniques in LTE environments, specifically using the Demodulation Reference Signal (DMRS) in uplink scenarios, supported by simulations. We present a method based on two approaches: one based on phase difference and the other utilising a codebook, both of which are less computationally intensive compared to traditional methods. Our study features simulations involving a base station equipped with a two-element Uniform Linear Array (ULA). The orthogonality of the DMRS sequences of Physical Uplink Control Channel (PUCCH) helps to segregate the users in the uplink and determine their angles of arrival even when they use the same time-frequency resources with as few as two antenna array elements. The results with the popular Multiple Signal Classification (MUSIC) algorithm using the uplink DMRS are also presented.