Optimized traffic flow assignment in multi-homed, multi-radio mobile hosts

Multi-radio mobile communication devices are increasingly gaining market share due to the diversity of currently deployed and continuously emerging radio access technologies. Multi-homing support in multi-radio terminals, i.e., simultaneous use of two or more radio interfaces, provides improved user experience through increase in available bandwidth capacity and reliability of wireless access. Furthermore, optimized assignment of application traffic flows to available interfaces and radio access bearer services contributes to economic and power consumption efficiency. We study the problem of traffic flow assignment in a mobile node, multi-homed through a set of different technology radio interfaces. We provide an analytical formulation for the problem and prove its hardness through transformation from the Multiple Knapsack Problem with Assignment Restrictions. Problem solutions are approximated with a heuristic algorithm that is based on local search and is characterized by efficient execution times for a wide set of realistic problem sizes. The quality of approximation is rather satisfactory and is evaluated through comparison of heuristic and exact solutions for a large set of randomly generated problem instances. Moreover, an evaluation of the approach through simulation supports these findings and provides an estimation of the associated mobility management overhead that is limited and allows real deployment of the decision mechanism.