Optimized Fairness Cell Selection for 3GPP LTE-A Macro-Pico HetNets

Pico cell has been brought to cellular networks as a new technology to deliver cost-effective coverage and capacity to hard-to-reach places, and also increase capacity by cell splitting in hotspots with very dense phone usage. However, according to existing strongest receiving signal association method, pico cells with the extremely low transmitting power are significantly limited in the presence of macro coverage. Thus, the new introduced pico frequency resource will not be fully exploited in this unbalanced user distributions among macro and pico cells. In this paper, by jointly considering the long term channel condition and load balance in this macro-pico coexisted heterogeneous network, we formulate the cell selection problem into a network wide proportional fairness optimization. Both optimal solution (by dynamic programming) and cost efficient algorithm (greedy heuristics) are proposed. In 3GPP LTE-A heterogeneous network scenario, the system-level performance evaluation shows that, compared with the conventional strongest signal cell selection scheme, the proposed optimized fairness cell selection methods could achieve significant performance gains especially for the cell edge users.