Jinsuk Pak

Determination of aggregation point using fermat’s point in wireless sensor networks

We propose a method for determining where to aggregate data from sensor nodes using Fermat’s point to save energy in wireless sensor networks. Unlike most aggregation schemes, our method does not need to construct any tree for aggregation of data. Simulation results show that Fermat’s point can be the most effective aggregation point in terms of energy efficiency and thus the network lifetime.

A Decentralized Hierarchical Aggregation Scheme Using Fermat Points in Wireless Sensor Networks

The energy cost for transmission is more expensive than receiving or sensing cost. In this paper, we propose a decentralized aggregation scheme using the Fermat points to save energy for transmitting redundant low-rate data on many-to-one flows in wireless sensor networks. It can reduce the number of transmissions needed to deliver from each source to the sink. Simulation results show that our scheme is better than the GIT (Greedy Incremental Tree) scheme in terms of the number of transmissions and network lifetime.

In-network processing for wireless sensor networks with multiple sinks and sources

Energy consumption is one of the most crucial issues in wireless sensor networks since sensor nodes are commonly battery-driven. Recently, several aggregation methods have been proposed to save energy by reducing the number of transmissions from source to the sink. They assumed a single sink for aggregation of data. In this paper, we propose an aggregation scheme for wireless sensor networks with multiple sinks. In our scheme, each node caches the gradient information collected from its local neighbors to determine the aggregation point for merging data to be delivered to multiple sinks. The experimental results show that our scheme can reduce the number of transmissions and thus save the energy more than the greedy incremental tree scheme and the shortest path scheme.

A MAC protocol using separate wakeup slots for sensor network

This paper presents a MAC protocol which uses separate wakeup slots for each sensor node in sensor networks. Most MAC protocols proposed for sensor network are inefficient under heavy traffic loads, in particular in high density network topology because of frequent collisions and long sleep latency. In this paper, we suggest a MAC protocol in which each node has a different wakeup schedule in the same duty cycle, and it joins the competition only for its own short wakeup slot when the receiver is ready to receive its data. Simulation results indicate that our scheme can reduce energy consumption and minimize idle listening which increases the power efficiency.

An adaptive frame-based admission control for multimedia traffic in wireless LAN

Improving the performance of delay-constrained video streaming over wireless networks is one of the most important issues for various multimedia-related applications, as well as for the efficient overall utilization of the wireless medium. In this paper, we propose a scheme for adaptive admission control and scheduling for frame-based multimedia traffic in the 802.11 wireless local area networks. The conventional scheduler used for IEEE 802.11e is not suitable for VBR traffic such as MPEG-4 because only a single fixed TXOP is allocated from the hybrid Coordinator. In our scheme, we divide an MPEG flow into three different classes of video-frames depending on the user-QoS, and Our scheme is distributed admission control for each divided videoframe types and poll scheduling adaptive admission control for the flow.

A MAC protocol to reduce sleep latency and collisions in wireless sensor network

This paper presents a MAC protocol which uses separate wakeup slots for each sensor node in sensor networks. Most MAC protocols proposed for sensor network are inefficient under heavy traffic loads, in particular in high density network topology because of frequent collisions and long sleep latency. In this paper, we suggest a MAC protocol in which each node has a different wakeup schedule in the same duty cycle, and it joins the competition only for its own short wakeup slot when the receiver is ready to receive its data. Simulation results indicate that our scheme can reduce energy consumption and minimize idle listening which increases the power efficiency.