Patent ID: 7683834

Claim:
A communications system comprising: at least J mobile wireless communications devices transmitting at a same time, where J≧2, and each mobile wireless communications device transmitting a source signal defined by a respective character set comprising a plurality of symbols, and at least one of the symbols in the respective character set being transmitted at a different power level so that the transmitted source signals from said at least J mobile wireless communications devices appear with at least L 1 to L J linearly independent power level time periods, where L j ≧1 and at least one L j >1; and a fixed communications device for separating source signals provided by M signal sources, where M≧2, and with said J mobile wireless communications devices providing J of the M source signals including up to (L 1 * . . . *L J ) linearly independent power level time periods, said fixed communications device comprising an antenna array comprising N antenna elements for receiving at least N different summations of the M source signals, where N≧1, a receiver coupled to said antenna array for receiving the at least N different summations of the M source signals, and a signal separation processor coupled to said receiver for forming a mixing matrix comprising the at least N different summations of the M source signals, the mixing matrix having a rank equal to or greater than (L 1 * . . . *L J )*N, said signal separation processor for separating desired source signals from the mixing matrix.