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 relays that constitute the spoke. It directs data transmissions by randomly 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 minimize 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 parameters 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 mechanism 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 simulation 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 significantly less sensitive to changes in the distribution of network nodes and their density.