Performance Analysis of Dynamic Spectrum Allocation in Multi-Radio Heterogeneous Networks

In heterogeneous networks, multi-radio access technologies (RATs) can coexist for a variety of traffic demands and it is called multi-RAT network. Also, cognitive radio enable to use white space of frequency band, and thus spectrum resources can be dynamically allocated. This paper analyzes an effect of multi-radio access (MRA) users, who simultaneously exploit multi-RATs, on network performance where dynamic spectrum allocation (DSA) is performed. Multi-dimensional Erlang loss (MDEL) model, which is based on queueing, is suitable to describe behaviors of single radio access users in multi-RAT networks under the performing DSA. Based on the MDEL model, extended MDEL model is proposed to investigate the effect of MRA users. As MRA users increase, blocking probability, utilization, and expected processing time of a user in the multi-RAT networks deteriorate, since the MRA users require multiple spectrum resources at a time. Numerical results verify the performance degradation resulted from the MRA users under the DSA and FSA scenarios.