Cell load imbalances in wireless networks degrade performance. Macro and small cell collocated deployments (heterogeneous scenario) constitutes a new problem for load balancing. This paper proposes a novel admission control algorithm for an optimal solution to the assignment of traffic flows. It jointly performs congestion control and inter-cell interference avoidance by means of a utility describing the cell's channel. Centralized and uncoordinated schemes are studied. The first is defined as an integer linear program, while the second builds on the best channel utility developed for the first and combines it with a stochastic admission process. Based on simulation evaluation, it is shown that uncoordinated is near-optimal, while providing a viable solution for uncoordinated small cell deployments. Finally, the best utility developed proved better than the traditional power allocation.