Cooperative signal reception and down-link beam forming in cellular mobile communications

A cooperative signal reception and down-link beam-forming algorithm is proposed for mobile communication systems employing phase-shift-keying (PSK) modulation. Down-link beam optimality is defined as maximizing the desired reference user´s average received power while keeping the noise power plus total amount of average powers received by other users less than or equal to a certain constant level. The proposed algorithm requires neither the detection of other user´s signals nor knowledge about the direction-of-arrivals (DOA)´s of the incident path components. Results of a series of exhaustive simulations are presented to demonstrate the overall performance of the proposed algorithm. For a hexagonal cell layout, the distribution of signal-to-interference power ratio (SIR) in a reference (central) cell with the optimal down-link beam is evaluated and compared with that with a unit gain omnidirectional antenna through computer simulations for an eight-element circular array. The beam-forming performances are also evaluated under several sets of practical parameter values with regard to the fading correlation