Byunghwa Lee

An adaptive rate control for congestion avoidance in wireless body area networks

The convergent feature of traffic in wireless body area networks (WBANs) makes congestion in certain areas which are the place of events and/or the location of sensor nodes near a sink. Congestion brings packet loss, retransmission, and delay at the node and it also causes the consumption of additional energy. Therefore there is no doubt that congestion needs to be controlled efficiently. In this paper, we suggest an adaptive rate control for congestion avoidance in WBANs. Our scheme performs rate control dynamically each node based on a predication model which uses rate function including congestion risk degree and valuation function, without requiring congestion detection and congestion notification steps. We carry out the operation of our scheme between the network layer and the data link layer and have demonstrated our rate control to be efficient. We also show that the negative effects from network congestion can be greatly mitigated as compared with a no rate control mechanism.

A Self-Adjustable Rate Control in Wireless Body Area Networks

The convergent feature of traffic in wireless body area networks (WBANs) makes congestion in certain areas which are the place of events and/or the location of sensor nodes near a sink. Congestion brings packet loss, retransmission, and delay at the node and it also causes the consumption of additional energy. Therefore there is no doubt that congestion needs to be controlled efficiently. In this paper, we suggest a self-adjustable rate control in WBANs. Our scheme performs rate control dynamically each node based on a predication model which uses rate function including congestion risk degree and valuation function, without requiring congestion detection and congestion notification steps. We carry out the operation of our scheme and have demonstrated our rate control to be efficient. We also show that the negative effects from network congestion can be greatly mitigated as compared with a no rate control mechanism.

Dynamic Channel Adjustable Asynchronous Cognitive Radio MAC Protocol for Wireless Medical Body Area Sensor Networks

Medical body area networks (MBAN) impose several requirements to the medium access control layer which have various contexts: energy efficiency, QoS providing, reliability. And a cognitive radio (CR) network should be able to sense its environment and adapt communication to utilize the unused licensed spectrum without interfering with licensed users. As CR nodes need to hop from channel to channel to make the most use of the spectrum opportunities, we consider asynchronous medium access control (MAC) protocols to be solution for these networks. The DCAA-MAC protocol presented in this paper has been designed has been designed specifically for wireless body area network with cognitive radio capability. The DCAA-MAC protocol has energy-efficiency, low latency, and no synchronization overhead by provide asynchronous and fast channel switching. Analytical models are shown to perform at low energy consumption, to scale well with network size.

An Implementation of AODV Testbed with Multi-metrics

The Ad-hoc On-demand Distance Vector (AODV) is the most typical reactive routing protocol in MANET. It has been extensively studied through not only computer simulations but also implementations on real network. In this paper, an implementation of AODV routing protocol with multi-metric was presented. In the implementation, an Uppsala University routing protocol, AODV-UU was modified in order to apply multi-metrics. Moreover, both AODV-UU and modified AODV-UU were implemented within a Linux-based test bed: a real ad-hoc network. Finally, the performance of both protocols was evaluated experimentally.

A Multiple-Metric Routing Scheme for QoS in WMNs Using a System of Active Networks

Wireless mesh networking is emerging as an important architecture for the future generation of wireless communications systems. The challenging issue in WMNs is providing Quality of Service (QoS). So, this paper proposes a multiple-metric routing scheme for QoS in WMNs using a system of active networks. The Active Network paradigm offers the attractive capability of being able to carry executable payloads that can change the characteristics of a given platform. In other words, network nodes not only forward packets, but also perform customized computation on the packets flowing through them. It provides a programmable interface to the user.

A Flooding Strategy for Data Delivery in Mobile Sensor Networks

In mobile sensor networks (MSN), MSN may have a high rate of communication failure since the routing path can be broken when some nodes on the path move to other position. So, MSN has to provide a means for low-cost and low-power routing to support mobility of sensor nodes. In this paper, a limited flooding scheme for routing in MSN is proposed to allow efficient energy utilization without requiring any complicated tasks for path maintenance.

The Continuous Communication Method for Mobile Circumstances in WMNs

The Hybrid Wireless Mesh Protocol is a mesh routing protocol that combines the flexibility of on-demand routing with proactive topology tree extensions. The Wireless Mesh Network consists of mesh points and stations. Even if mesh points or stations have mobility, the path should be kept continuously. The Direction of present mobility research is achieved by research in a mobility of stations. In case the MAP moves, this research is very weak. The proposal scheme emphasized in the MAP (Mesh Access Point) mobility. After the Mesh Access Point moves, it re-establishes an existing full path by using the RRER message. However, our scheme is available in an existing path that is changed locally by using a MR (Message Registration) -message which accomplishes locally reestablished path techniques. In this paper, we analyze problems in existent HWMPs path establishment technique.We propose the New Path Selection Scheme by using MR-message produces. Simulation results show that this proposal scheme is designed to reduce packet loss.