Multiplication of cellular radio capacity by blind adaptive spatial filtering

A scheme for cellular radio which greatly increases the allowable number of simultaneous users in each cell is proposed. The scheme employs space-division multiplexing by means of an adaptive antenna array at the base station (1) to separate the temporally and spectrally overlapping signals of users that arrive from different locations within the cell and to mitigate multipath fading and shadowing at the base station and (2) by reciprocity to transmit directively to minimize interfering signals arriving at the mobile units and to mitigate multipath fading and shadowing at the mobile units. A novel aspect of the proposed scheme is that no training signals are required for adaptation, nor are computationally intensive direction-finding methods required, nor is any calibration data required for the array. Results from computer simulations on the performance of the new scheme show that the proposed scheme can accommodate up to five times as many users as a proposed CDMA scheme using the same system bandwidth