Adaptive CDMA cell sectorization with linear multiuser detection

We consider the problem of adaptive cell sectorization in a CDMA system when the receiver employs a linear multiuser detector. Specifically, given the number of sectors and terminal locations, we investigate how to appropriately sectorize the cell, such that the total transmit power is minimized, while each user has acceptable quality of service, under the assumption that the base station employs linear multiuser detectors. The resulting joint optimization problem has high complexity for arbitrary signature sequences, so we concentrate on the tractable case where the square of the crosscorrelation values between the signature sequences are equal. We formulate the sectorisation problem for different linear detectors. The optimum sectorization problem with linear multiuser detector has the same complexity as the one with the matched filter. Numerical results suggest that significant power saving is achieved by incorporating better receiver structures, i.e. MMSE detector, or decorrelator.