Combining directional channel modelling with beamforming adaptive antennas for UMTS

The conjugate gradient algorithm is applied to antenna beamforming at the base-station, in the uplink, for UTRA-TDD. Specific microcell, street type propagation scenarios are used, applying a wideband directional channel model, based on the elliptical single bounce model. The scenarios are also characterised by the placement of a variable number of mobile interfering terminals, at different positions and groupings. Simulation average results mainly cover final beamforming processing gain and signal-to-noise ratio, focusing on their relation to propagation conditions. Algorithm convergence evolution and complexity are summarily addressed. The high dependency of the algorithm´s performance on the propagation channel and on the number and positioning of the several mobile terminals has been confirmed, establishing such relationships. The average gain values present a minimum value of 7.3 dB, for all scenarios. It has also been concluded that a power control procedure highly improves the beamforming gain, in scenarios where the near-far effect is critical, rising up to 6.9 dB