On the Impact of Multi-mode Terminals in Heterogeneous Wireless Access Networks

Beyond 3G (B3G) networks will encompass, among other features, a wide range of radio access technologies (RATs) providing users with a flexible and efficient access to the increasing pool of demanding services. This will allow users to get connected using the access technology that is most suitable according to some specified criteria. Consequently, to take full advantage of B3G networks, mobile terminals will need to support a larger set of capabilities. Among those, the support of different RATs, i.e. multi-mode capacity, is a must. This paper addresses the impact of multi-mode terminals in an EDGE/UMTS heterogeneous network with multi-service provisioning. Results indicate that multi-mode terminal availability should be considered when designing common radio resource management strategies in heterogeneous wireless access networks. Specifically, a service-based initial RAT selection policy is evaluated, revealing different behaviors for different multi-mode terminal availabilities and service-class mixings. In order to compensate the limitations imposed by non-multi-mode terminals, it is suggested to actuate over GERAN by using a resource reservation scheme for interactive users. By doing so, we tradeoff the QoS between multi-service/multi-mode users.