A unified interference/collision model for optimal MAC transmission power in ad hoc networks

Abstract

Abstract:In this paper we address the issue of controlling transmission power in power-aware adhoc networks. We argue that minimum transmission power is not always optimal. Previous work that minimizes the transmission power does not consider both the energy consumed in collision resolution and the energy disbursed to overcome the interference resulting from neighboring nodes. We investigate the basic transmission power control for the 802.11 MAC protocol, in which the control frames and the data frames can be transmitted at different power levels. A unified collision and interference model of a uniformly distributed network is constructed. Based on this model, the end-to-end network throughput and the total energy consumption of the network are examined for different network parameters. For a net-work with a given node density, our results show the optimal transmission power for control messages and for data messages that will yield maximum throughput and minimum energy consumption per message.

A topology control algorithm for wireless sensor networks that considers overhearing

“…Topology control has been studied in the context of static networks as well as of networks with mobile nodes (e.g., [1]- [3], [5]- [10], just to name a few). Finding an optimal mapping of transmission power to nodes in such a way that the overall energy consumption on the network is minimized was proven to be an NP-Complete problem [4].…”

“…The effect of overhearing is also considered in [9] and [10]. The authors of these papers, however, did not have as objective to propose a distributed algorithm for power assignment.…”

“…Although localized algorithms for topology control in WSNs have been the subject of much research, only few of them consider the effect of overhearing (e.g., [6], [9], [10]). According to frequently adopted energy models (e.g., [11]), each node spends an amount of energy during reception which is a constant value multiplied by the time the node remains at this state.…”

“…Since wireless transmissions are performed by broadcasting, all nodes that are in the radio range of a transmitter will hear the transmission, even if they are not intended receivers of it (except in cases such as when nodes have their radio devices turned off). Although neglected in many previous works, overhearing has an impact on topology control [10].…”

Interference Modeling for Wireless Ad Hoc Networks

“…Grid models have been proposed to compute interference (Gobriel et al, 2004), (Liu & Haenggi, 2005), which take advantage of the regular placement of the nodes. This orderly topology is a good starting point for static networks; however, it does not apply for MANETs.…”