In the future fifth generation (5G) networked society, devices will integrate heterogeneous radio access technologies (RATs) to improve the network performance and the user quality of experience. In this paper, we focus on softer vertical handover (SRVH), discussing its feasibility and its performance in a multiuser scenario. Specifically, a new taxonomy for vertical handovers is proposed to resolve ambiguities in current terminology and technical issues related to SRVH implementation are discussed. Then, a simple but accurate analytical model is proposed to evaluate the performance of SRVH and results are provided with reference to best effort services in the presence of two RATs. Two case studies are considered, a mobile controlled approach with uncoordinated RATs and a network controlled approach with coordination among RATs. Results demonstrate that SRVHs are useful to allow finer granularity in resource allocation when there is coordination among RATs, although they fail to provide throughput improvements if they are selfishly performed by mobile terminals.
['Alessandro Bazzi', 'Barbara M. Masini', 'Alberto Zanella', 'Davide Dardari']
Performance evaluation of softer vertical handovers in multiuser heterogeneous wireless networks