Evaluation of reverse link performance of a CDMA system with imperfect beamforming

Reverse link capacity of a direct-sequence code-division multiple-access (DS-CDMA) system in a multicell environment has been studied recently and significant capacity improvement due to the use of beamforming has been observed. However, system performance with beamforming is affected by several impairments, such as direction of arrival (DOA) estimation errors, array perturbations and mutual coupling. The reverse link performance of CDMA systems with beamforming under these impairments (imperfect beamforming) is investigated. A simplified beamforming model is developed to evaluate the system performance in terms of user capacity and outage probabilities. Both signal-to-interference ratio (SIR) based power control and strength-based power control are considered. The capacity degradation due to different impairments is shown and outage probabilities under different power control schemes are compared.