HCMM: Modelling spatial and temporal properties of human mobility driven by users' social relationships

In Mobile Ad Hoc Networks (MANETs), the mobility of the network users can heavily affect the performance of networking protocols because it causes sudden connectivity changes and topological variations. This is even more important in recent promising paradigms proposed in this field, such as opportunistic and delay tolerant networks. For this reason, it is important to understand the characteristics of the user movements in order to properly handle mobility when designing networking protocols for mobile ad hoc networks. In addition, it is highly desirable to have a mobility model that accurately reproduces the user mobility, thus enabling researchers to evaluate, either analytically or by means of simulations, their protocols under realistic mobility conditions. Recently, there have been many studies aimed to uncover the nature of human movements. In this paper, based on recent literature, we identify three main properties that are fundamental to characterize human mobility. Then, we propose a mobility model (HCMM) that integrates all these three features. To the best of our knowledge, the model proposed is the first one that combines notions about the sociality of users with spatial properties observed in real users movement patterns, i.e., their preference to spend time in a limited number of popular locations and to preferentially select short distances over longer ones. We study the HCMM both through simulation and analysis. Based on this study, we highlight some of its important temporal and spatial features, and we show that they are correctly reproduced in terms of key indicators such as jump size and inter-contact time distribution. (C) 2010 Elsevier B.V. All rights reserved.