Dynamic spectrum allocation in heterogeneous wireless networks under interference constraints across the cell coverage

In order to improve spectrum utilization, dynamic spectrum allocation (DSA) schemes with interference management have been widely investigated, and a special interest is in the current heterogeneous wireless network (HWN) environment. In the previous work, the approach that guarantees quality of service for the cell-boundary user is extensively used in the DSA scheme. However, such approach gives a pessimistic result. In this paper, we design a DSA scheme for the HWN system, which adopts relatively accurate interference constraints. First, considering that users may randomly locate over the cell, we propose interference constraints across the cell coverage, in which the interference experienced at a point is controlled below the level suffered when using fixed spectrum allocation in only a single network, and the proportion of the cell area where interference is controlled reaches the required area coverage probability. Then under the interference constraints, we formulate the downlink DSA scheme as a combinatorial optimization problem. As the problem is NP-hard, to reduce the computational complexity, we propose two greedy heuristic algorithms for its solution. Simulation results show that the DSA scheme could improve the total spectrum utility for operators and increase the satisfaction rate of spectrum demands for base stations. Copyright (c) 2013 John Wiley & Sons, Ltd.