EXTENDING SDMA BY POWER LOADING FOR SPATIALLY NON-SEPARABLE USERS

摘要

The invention relates to a method for performing downstream transmissions in a wireless communications network (1 ), the method comprising: selecting at least a first and a second mobile station (MS1,MS2 ) in at least one of a plurality of beams (B1 (i) to B4 (i)of a communications cell (Bj) using space-division multiple access, SDMA, the first mobile station (MS1) having higher Signal to Interference and Noise Ratio, SINR, than the second mobile station (MS2), generating a downstream signal (b1 (j)) by combining a first data signal (d1 (j)) for the first mobile station (MS1 ) with a second data signal (d2 (j)) for the second mobile station (MS2) using non-zero amplitude scaling factors (f1,1 (j), f2,1 (j), transmitting the downstream signal (b1 (j)) from a base station (BSj) of the communications cell (Bj) to the first and second mobile stations (MS1, MS2), in the first mobile station (MS1 ), before recovering the first data signal (d1 (j)) from the transmitted downstream signal, removing the contribution of the second data signal (d2 (j)) from the transmitted downstream signal, preferably by using non-linear interference cancellation, and in the second mobile station (MS2), recovering the second data signal (d2 (j)) from the transmitted downstream signal treating the contribution of the first data signal (d1 (j)) as noise. The invention also relates to a communications cell (Bj) as well as to a communications network.