OR-based block combination for asynchronous asymmetric neighbor discovery protocol

The neighbor discovery protocol (NDP) is one of the critical research subjects in wireless sensor networks (WSNs) for efficient energy management of sensor nodes. A block design concept can be applied to find a neighbor discovery schedule that guarantees at least one common active slot between any pair of sensor nodes. However, the block design-based solutions in literature are not flexible enough because block design cannot support asymmetric asynchronous operations. In this paper, we introduce a new approach for asymmetric asynchronous neighbor discovery protocol that combines two optimal block designs using the OR operation. OR-based block combination solves the problem of original block design, which cannot support asymmetric scenarios. We evaluate the performance of OR-based block combinations using a simulation study. According to our simulation results, OR-based block combination performs up to 71% better than other asymmetric algorithms, such as U-Connect and Disco with 10% and 1% duty cycles.