Joint Channel Estimation with Array Antennas in OFDM based Mobile Radio Systems

This paper investigates the performance gain for pilot-aided channel estimation in the uplink of multiuser OFDM mobile radio systems, when array antennas are applied at the receivers. The application of array antennas allows the exploitation of directional information of the desired and the undesired signals at the receivers based on the array geometry and the directions of arrival of the considered signals. The technique termed joint channel estimation is derived in the paper. The maximum likelihood estimation principle and the minimum mean square error estimation principle are applied for joint channel estimation. Based on an exemplary multiuser OFDM air interface also described in the paper, both channel estimation approaches are discussed and their performance in the multiantenna scenario is investigated.