Common radio resource management for WLAN-UMTS integration at radio access level

WLAN-UMTS integration in the UMTS-based approach can be performed either at the UMTS Core Network (CN) or Radio Access Network (UTRAN). Both interworking solutions provide the operator with additional license-free bandwidth and promise good handover performance. Integration at the radio access level has the advantage that the UMTS core network protocols remain unaffected and the interworking architecture deals with radio aspects only. Abstract—Integration of UMTS and WLAN can be performed at different levels. A promising interworking approach embeds the WLAN into the UMTS radio access network. It provides additional license-free capacity to operators and good vertical handover performance. As the WLAN is attached directly to the UMTS radio resource manager, this approach allows possibility of collocation of resource managers of both networks. Common radio resource management allows more efficient use of resources and facilitates vertical handover management. The paper discusses this issue for two architectural options for WLAN-UMTS integration at radio access level. In addition, when increasing the degree of coupling of the networks, the resources can be utilised in a more efficient way. In the case of integration at radio access level, the WLAN is directly attached to the Radio Network Controller (RNC), which is responsible for the UTRAN Radio Resource Management (RRM). As the information on the networks usage is available locally, the RNC represents a suitable entity to manage the network resources of both networks. Such a Common Radio Resource Management (CRRM) entity for both networks will optimise the resource utilisation in terms of network load, cost, QoS requirements, etc. Besides, due to the global view of the available resources, it can enhance the management of vertical handover. Keywords—UMTS, WLAN, radio access integration, common radio resource management