Topology Control and Mobility Management in Mobile Ad Hoc Networks (Invited Talk Abstract)

Summary form only given. A mobile ad hoc networks (MANETs), it is important to select an appropriate transmission power for each node, called topology control, to reduce energy consumption and signal interference while still maintaining network connectivity. In a topology control protocol, each node selects a few logical neighbors from its 1-hop neighbors based on its local view, constructed by exchanging periodical "Hello" messages among neighbors, and uses a small transmission range to cover those logical neighbors. Our recent study showed that the majority of topology control protocols are unable to maintain connectivity in MANETs due to node mobility. One challenging problem involved is to construct consistent local views for the selection of a correct set of logical neighbors. All existing methods that enforce consistent local views require a certain degree of global synchronization. This talk first describes several popular topology control schemes and problems caused by node movement. Then we introduce a mobility management mechanism called weak consistency to address this problem. Compared with previous consistency schemes, this new mechanism requires no inter-nodal coordination and incurs no extra overhead. We show that a wide range of localized topology control protocols can be enhanced to ensure correct decisions based on local views that are weakly consistent. It is also proved that two recent "Hello" messages from each node are sufficient to construct weakly consistent local views, when each node updates its local views instantaneously, and three recent "Hello" messages are enough when each node updates its local view once per "Hello" interval