Abstract
Delay tolerant networks (DTNs) are a type of emerging mobile wireless network that experience long delays, intermittent disruption, buffer space and energy limitations, node irregularities and frequent mobility. To this end, many protocols take advantage of the flooding mechanism to increase the probability of successful message transmission. However, sending too many copies of each message may result in large network overhead and communication cost. Based on the Spray and Wait (S&W) algorithm, we propose an improved Adaptive Spray and Wait scheme, named ASW, for different delay tolerant network scenes. In this paper, we define a hybrid utility metric combined with multiple variables, delivery probability and similarity. Then, we distribute message copies in accordance with the proportion of the utility value to optimize the delivery ratio. Extensive simulations have been conducted to verify the efficiency of our proposed algorithm. In addition to the comparison, the results also show that our proposed algorithm achieves a better performance in terms of the delivery ratio and average latency than the other three protocols