Inter-cell coordination with inhomogeneous traffic distribution

We study the optimal division of cells into different service areas served under different coordinated transmission modes, i.e. combinations of base stations simultaneously transmitting, in order to avoid the adverse effect of inter-cell interference and to maximize the system capacity. We focus on the general case where the traffic load is inhomogeneous and give a complete characterization of the optimum for two-cell and three-cell systems in terms of a set of necessary conditions. An example of a three-cell system with a traffic load having a gradient in an arbitrary direction is numerically worked out.