  In duty-cycled wireless sensor networks, deployed sensor nodes are usually
put to sleep for energy efficiency according to sleep scheduling approaches.
Any sleep scheduling scheme with its supporting protocols ensures that data can
always be routed from source to sink. In this paper, we investigate a problem
of multi-hop broadcast and routing in random sleep scheduling scheme, and
propose a novel protocol, called DQSB, by quasi-synchronization mechanism to
achieve reliable broadcast and less latency routing. DQSB neither assumes time
synchronization which requires all neighboring nodes wake up at the same time,
nor assumes duty-cycled awareness which makes it difficult to use in
asynchronous WSNs. Furthermore, the benefit of quasi-synchronized mechanism for
broadcast from sink to other nodes is the less latency routing paths for
reverse data collection to sink because of no or less sleep waiting time.
Simulation results show that DQSB outperforms the existing protocols in
broadcast times performance and keeps relative tolerant broadcast latency
performance, even in the case of unreliable links. The proposed DQSB protocol,
in this paper, can be recognized as a tradeoff between broadcast times and
broadcast latency. We also explore the impact of parameters in the assumption
and the approach to get proper values for supporting DQSB.
