A digital beamformer concept for GSM1800 uplink: simulation results for various test environments

Performance of a digital beamforming concept for GSM1800 uplink was studied by simulation. The receiver algorithm is based on direction-of-arrival (DOA) estimation and digital beam steering. The beamformed signal is processed by a multidimensional MLSE equalizer which allows interference suppression. The principal DOA is estimated using the training sequence in order to better separate the desired user and the co-channel interfering users. Simulation results for urban, suburban and rural environments showed that using 8-element antenna arrays offers a gain of 5-6 dB in SNR at 8% BER compared to a conventional 2-branch GSM-receiver (noise limited environment). In interference limited case the receiver performance varied a lot depending on the number of signal paths and their azimuth direction from the co-channel interference.