Can a Packet Walk Straight Through a Field of Randomly Dying Location-Unaware Wireless Nodes?

A protocol, dubbed BeSpoken, steers data transmissions along a straight path called a spoke through a wireless sensor network with many location-unaware nodes. BeSpoken implements a simple, spatially recursive communication process, where a set of control packets and a data packet are exchanged among daisy-chained re-lays that constitute the spoke. It directs data transmissions by ran-domly selecting relays from crescent-shaped areas along the spoke axis created by intersecting transmission ranges of control and data packets. To specify design rules for protocol parameters that min-imize energy consumption while ensuring that spokes propagate far enough and have a limited wobble with respect to the spoke axis, our model of the spoke propagation matches the protocol pa-rameters to the density of network nodes, assuming that nodes are spatially distributed as a Poisson point process of known uniform intensity. To avoid this requirement, we propose and characterize an adaptive mechanism that ensures desired spoke propagation in a network of arbitrary density. This necessitates a qualitatively new protocol model used to evaluate the spoke propagation under both the basic and the adaptive protocol. The introduced adaptive mech-anism repairs the spoke when the crescent-shaped area is empty which may occur in the case of network thinning and as a result of random or arbitrary sensor death. Our analytical and simula-tion results demonstrate that the adaptive BeSpoken creates longer spokes both in networks with uniform distribution of nodes and in networks with holes. In addition, the adaptive protocol is signifi-cantly less sensitive to changes in the distribution of network nodes and their density