Flooding strategy for target discovery in wireless networks

In this paper, we address a fundamental problem concerning the best flooding strategy to minimize cost and latency for target discovery in wireless networks. Should we flood the network only once to search for the target, or should we apply a so-called "expansion ring" mechanism to reduce the cost? If the "expansion ring" mechanism is better in terms of the average cost, how many rings should there be and what should be the radius of each ring? We separate wireless networks based on network scale and explore these questions. We prove that two-ring and three-ring schemes can reduce the cost of flooding compared to a single attempt, and we provide a general formula to determine good parameters for the two-ring and three-ring hop-based flooding schemes. Through simulations, we show that choosing flooding parameters according to our techniques gives performance close to that of ideal flooding schemes. Afterwards, we extend our work from the single target discovery problem to the multi-target discovery problem. We show that a properly chosen searching radius can save much more searching cost than a simple radius selection scheme for multi-target discovery problems.