Optimal Admission Control Policies for Heterogeneous Wireless Networks

In the near future, demand for HeterogeneousWireless Networking (HWN) is expected to to increase. QoS provisioning in these networks is a challenging issue considering the diversity in wireless networking technologies and the existence of mobile users with different communication requirements. In HWNs with their increased complexity, “the curse of dimensionality" problem makes it impractical to directly apply the decision theoretic optimal control methods that are previously used in homogeneous wireless networks to achieve desired QoS levels. In this paper, optimal call admission control policies for HWNs are considered. A decision theoretic framework for the problem is derived by a dynamic programming formulation. We prove that for a two-tier wireless network architecture, the optimal policy has a two-dimensional thresholdbased structure. Further, a novel algorithm called Structured Value Iteration is proposed as a numerically efficient method to determine the optimal policy in terms of its thresholds. Extensive simulation experiments are conducted. The numerical results show that the proposed algorithm is efficient in terms of its time-complexity and in achieving the optimal performance.