Local versus global power adaptive broadcasting in ad hoc networks

Broadcasting is an ad hoc network critical function component, and, in many deployments, making it power efficient is extremely important. Current power adaptive approaches proposed for broadcasting can be grouped into (a) centralized or omniscient schemes, and (b) decentralized or localized schemes. Due to the absence of global information, localized algorithms may not produce optimal or near-optimal solutions. On the other hand, global knowledge is not typically available to nodes and may be extremely expensive to disseminate. We examine the importance of the lack of global information on the performance of localized approaches. We have performed extensive simulations and compare the performance of localized power adaptive broadcasting with the performance of the well-known broadcast incremental power (BIP), an omniscient algorithm. We analyze the behaviors of the two protocols and identify the reasons for the differences in behavior. We observe that while the global state does provide better performance in terms of energy efficiency, the localized scheme performs better in terms of the latency incurred in the broadcast. Based on the observed behavioral traits of the two protocols, we suggest changes by which the energy consumption with the localized scheme is reduced by as much as 20%, while incurring almost no penalty in terms of latency.