Limited Complexity Optimization of the Uplink Performance in Cloud Cellular Networks

We consider a cooperative cellular network where the signal from a mobile is detected jointly by base stations close to it using a minimum-mean-square-error (MMSE) estimator. We assume a network where different numbers of cooperating base stations can be used for the detection of each mobile. We also assume that all signals are delivered to a processing center which has limited computational capabilities. We present an upper bound on the achievable weighted sum rate for a given computational complexity. We also derive a simple and practical optimization scheme that is based on asymptotic results for the spectral efficiency of a typical link in a Poison point process model. The derived scheme results in a computational savings over schemes that use a fixed number of cooperating base stations for each mobile. The suggested scheme also enables an easy tuning of the computational complexity, according to system needs and energy requirements.