Network-Centric Joint Radio Resource Policy in Heterogeneous WiMAX-UMTS Networks for Streaming and Elastic traffic

The convergence of wireless networks is a key solution to deal with the ever-increasing need for bandwidth. In this compound radio environment, users can use concurrently diverse services through multiple RATs. In this paper, we consider a heterogeneous network where cells include two co-localized radio access technologies (RAT): WiMAX and UMTS. The predominance of these systems in nowadays mobile networks underlines the relevance of our choice. We consider the downlink channel for both RATs and two service classes: streaming and elastic traffic. We propose a joint radio resource management (JRRM) algorithm responsible of routing every arriving user to one of the two RATs, while taking into account the load of each RAT, the spatial distribution of already accepted users, the location of the newly admitted user, and its influence on global performance. In a study based on the semi Markov decision process (SMDP) theory, we show how to obtain an optimal policy that maximizes a predefined reward function accounting for both the operator and user satisfaction. In fact, the reward function consists of a financial gain component, an aggregate throughput component and a blocking cost.