Load balancing in the call admission control of heterogeneous wireless networks

Abstract

In the next generation wireless systems (NGWS) the end user will be able to connect to any of the different available access networks. The end user will also be able to roam seamlessly within the access networks through vertical handoffs. While these features of the NGWS are very advantageous for service providers as well as end users, technically they bring about many challenges to the joint call admission control (JCAC) algorithm. In addition to making decisions during new or handoff calls, the JCAC should perform load balancing among the different access networks. In this paper, we extend the hierarchical joint call admission control algorithm by proposing a scheme for load balancing. In the hierarchical approach, the work of the JCAC is divided into the algorithms horizontal call admission control (HCAC) and vertical call admission control (VCAC). A VCAC manages the inter-network admission of multiple access networks while in each access network there is an HCAC that controls its intra-network admission. In the proposed load balancing scheme, each HCAC in a heterogeneous environment periodically sends a load report to the VCAC. The VCAC makes a comparison of the load reports and makes a decision for load balancing.