A comp downlink transmission system verified by cellular field trials

It is well known in theory that a coordinated multi-point downlink transmission can lead to a significant increase in spectral efficiency for cell-edge users, if channel state information at the transmitter is available. A closed-loop system in conjunction with measurement results of a cellular test bed is presented to conduct a performance comparison between cooperative and non-cooperative base stations. Since exhaustive field trials with various spatial configurations are very time-consuming, closed-loop real-time measurements were performed on selected positions. The achieved results verify that the observed spectral efficiencies agree with simulative performance predictions based on characterizations of the physical environment. This methodology has been utilized to anticipate the performance in the entire cell area by more feasible field trials. The achieved cooperation gains are weighted by the geometry factor proportions to draw the comparison with conventional cellular systems.