Overview of radio resource management (RRM) issues in multi-radio access systems

The concept of multi-radio access networks is currently considered as a strong candidate for the next generation wireless access networks. This concept incorporates conventional cellular networks such as GERAN or UTRAN for wide area coverage while local-area networks such as IEEE 802.11, HIPERLAN/2, and/or several personal networks (PN) interconnected in ad-hoc fashion are covering the local traffic hot-spot areas. The new radio access systems that will be developed in the future could also be included in this multi-radio concept because it is difficult (if not impossible) to design a single wireless access system that optimally works in different conditions and with different requirements. The radio resource management (RRM) in multi-radio access networks becomes a very challenging issue. The overall goal of the RRM functions is to optimally utilize the available radio resources and give the users the requested communication quality at affordable cost. Therefore, this paper presents an overview of the most important RRM issues for multi-radio access networks and gives recommendations for further studies in this field.