METHOD AND APPARATUS FOR INTERFERENCE REJECTION COMBINING AND DOWNLINK BEAMFORMING IN A CELLULAR RADIOCOMMUNICATIONS SYSTEM.

摘要

RECENTLY, INTERFERENCE REJECTION COMBINING TECHNIQUES HAVE BEEN PROPOSED WHICH CAN INCREASE SIGNIFICANTLY THE PERFORMANCE OF THE UPLINK IN C/I LIMITED ENVIRONMENTS. ANOTHER INTERESTING PROPERTY OF THE IRC TECHNIQUES IS THAT THEIR C/I PERFORMANCE DOES NOT DEGRADE AS THE CORRELATION BETWEEN THE RECEIVED SIGNALS INCREASES. THIS FEATURE OF IRC TECHNIQUES IS EXPLOITED IN THE PRESENT INVENTION TO ALLOW FOR A REDUCED SPACING BETWEEN THE ANTENNAS (270A, 2708; 270A'', 2708''). ACCORDING TO ANOTHER ASPECT OF THE PRESENT INVENTION, THE PERFORMANCE OF THE DOWNLINK IS IMPROVED USING BEAMFORMING TECHNIQUES TO "STEER" BASE STATION TRANSMISSIONS TOWARD A DESIRED MOBILE STATION (120). IN THIS WAY, THE PERFORMANCE OF THE DOWNLINK IS IMPROVED USING BEAMFORMING TECHNIQUES TO A DEGREE SIMILAR TO THAT AT WHICH THE UPLINK HAS BEEN IMPROVED USING IRC TECHNIQUES. THIS ALLOWS THE SYSTEM DESIGNER TO MORE FULLY EXPLOIT THE VARIATIONS IN SYSTEM DESIGN ASSOCIATED WITH IMPROVING THE UPLINK PERFORMANCE. (FIGURE 8)