View consistency for reliable topology control in mobile ad hoc networks

In localized topology control protocols for mobile ad hoc networks (MANETs), 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. Transmission range reduction conserves energy and bandwidth consumption, while still maintaining the network connectivity. However, our recent study showed that the majority of localized topology control protocols are unable to maintain connectivity in MANETs, due to network dynamics such as 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. In this paper, we propose a new 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