Adaptive Network Selection Scheme for Overlaid Heterogeneous Networks with Time-Varying Load

In this paper, an adaptive network selection scheme for a wireless communication systemwith overlaid cellular network structure is described. Most network selection schemes for overlaidcellular network divide the calls to into two groups, according to their speed or mean dwell time.After comparing user speed or mean dwell time with a given threshold, these schemes allocate anew or handoff call to a selected micro-cell or macro-cell. The proposed scheme not only considersuser speed, but also takes the residual capacity of the micro-cell and macro-cell into account todecide a suitable network. The given user speed threshold in the proposed scheme is not fixed;instead, it is adaptively changed for a time on either the user speed, or on the residual capacity ofthe micro-cell and macro-cell. We used computer simulations to investigate and compare ourpropose scheme with the static threshold scheme.