Abstract
Several mobile computing applications require that both the order and location of occurrence of events be taken into account during decision making. Thus, processes need to track the location of nodes and synchronize their clocks. The Global Positioning System can be employed to mimic a global virtual clock that keeps the local clocks of participating nodes in synchrony with each other. The global virtual clock in conjunction with a space–time vector can track the mobility of nodes. Nodes can prioritize resource requests on the basis of request time as well as the requester's distance from the resource. Two distributed mutual exclusion algorithms that employ the space–time vector are presented. The error in the estimates of a mobile node, due to clock drift, about the region in which other mobile nodes may be present is formulated. Various resource allocation policies can react differently to such errors leading to performance differences. However, every policy should ensure that resource allocation has the properties of safety, deadlock freedom, liveness, and fairness.
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Prakash, R., Baldoni, R. Causality and the Spatial–Temporal Ordering in Mobile Systems. Mobile Networks and Applications 9, 507–516 (2004). https://doi.org/10.1023/B:MONE.0000034704.13096.22
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DOI: https://doi.org/10.1023/B:MONE.0000034704.13096.22