Poster abstract: On the spatial characteristics of the gray region for 802.15.4 radios

Packet loss and energy consumption in sensor networks depend critically on the quality of the network's wireless links. In turn, link quality depends on the environment in which the RF signals propagate and the locations of the link's endpoints. Experimental results have shown that a low-power wireless link can be in one of three states or ‘regions’, as the inter-node distance increases: connected, transitional (gray), and disconnected. The gray region is characterized by extreme variability, whereby small differences in distance or end-point locations can lead to pronounced differences in loss rates. However, not all is lost. This work investigates the spatial characteristics of the gray region and experimentally shows that one can efficiently identify links with low loss rates within the radio's gray region. One of the possible applications of this finding is in the design of sparse, yet low-loss network deployments.