CDMA reverse link capacity with antenna arrays in a multipath fading environment

In this paper, reverse link capacity of a signal-to-interference ratio (SIR) based power-controlled direct-sequence code division multiple access (DS-CDMA) system, with the use of an antenna array and a RAKE receiver in a multiple cell environment, is investigated. Both transmit and receive beamforming in the reverse link are considered. Instead of using tedious iterative methods, reverse link user capacity represented by a simple closed-form expression is derived, which relates to the number of antennas, the number of RAKE receiver fingers, a target SIR, and the processing gain. The most efficient distribution of antenna elements between the base stations and the mobile stations to maximize the user capacity is observed through the numerical results, which also show significant capacity improvement by increasing the number of the antennas and RAKE receiver fingers.