One aspect to cross-layer design in sensor networks

In one model of a distributed large scale sensor network a roving "base-station" polls whatever sensors are within its field of view as to their (local) decisions on a common hypothesis. A simple variation on the ALOHA protocol is assumed, and the collisions between sensor observations are a serious concern. In this paper we examine a scheme in which sensors' quantization is, in a sense, ternary: the transmitted decision can be "no" or "yes", but the local sensor can choose not to respond. Thus, sensors whose observations are uninformative reduce the communication load, and thereby improve the ability of those sensors with important data to be heard there is consequently a cross-linking between detection and communication strategy. The results appear to be impressive.