Unidirectional link counter - a routing protocol for wireless sensor networks with many unidirectional links

Experiments with wireless sensor networks have shown that asymmetric and unidirectional links occur often. Protocols that detect these links on the link layer have been proposed, however, unidirectional links represent a challenge as well as a chance across all layers. Still, most routing protocols prefer to use only bidirectional links. In this paper we present Unidirectional Link Counter, a routing protocol that collects information about the unidirectional links on a path to make routing decisions. The collected information can furthermore be used for more effective neighborhood management and better quality estimation.