Application of space division multiple access to mobile radio

An approach is proposed to introduce a space division multiple access (SDMA) component into a frequency/time division multiple access (FTDMA) mobile radio system like the European GSM system providing higher frequency reuse and spectral efficiency. Except from signalling aspects the mobiles remain uneffected by the presented SDMA method without any need for antenna diversity or more sophisticated equalizers. Additional hard- and software-demands due to the new SDMA features are only restricted to base stations as they have to be equipped with an adaptive antenna array. This array is used to separate wavefronts in coherent multipath environments by means of a new algorithm. The number of antenna elements needed is significantly lower than the number of wavefronts impinging on the array.