Md. Obaidur Rahman

Multipath Congestion Control for Heterogeneous Traffic in Wireless Sensor Network

In order to achieve higher reliability and load balancing various multipath routing protocols have been proposed in Wireless Sensor Network. Moreover, wireless sensor network typically incorporates heterogeneous applications within the same network. A sensor node may have multiple sensors i.e. light, temperature, seismic etc with different transmission characteristics. Each application has different characteristics and requirements in terms of transmission rates, bandwidth, packet loss and delay demands may be initiated towards the sink. But achieving desired throughput for diverse data while disseminating through multiple paths is non trivial task as occurrence of congestion through multipath is obvious. In this paper we propose an efficient scheme to control multipath congestion so that the sink can get priority based throughput for heterogeneous data. We have used packet service ratio for detecting congestion as well as performed hop-by-hop multipath congestion control based on that metric. Finally, simulation results have demonstrated the effectiveness of our proposed approach.

A QoS Adaptive Congestion Control in Wireless Sensor Network

In wireless sensor networks congestion occurs in intermediate nodes while data packets travel from source to sink. Congestion causes packet loss which in turn drastically decreases network performance and throughput As sensors are energy constraint so it is a decisive task to detect the congestion and congested regions in a network to perform congestion control. In addition to that different application i.e. real time and non-real time data in sensor network have different QoS (delay, link utilization, and packet loss) guarantee requirement In this paper we proposed a new QoS adaptive cross-layer approach to control the congestion and support QoS guarantee for different application data in sensor network. This approach maintains two congestion control algorithm to control namely short-term and long-term congestion. To ensure real time and non-real time data flow, hop-by-hop QoS aware scheduling and QoS distributed MAC Manager are considered. The experimental outputs of this work are able to show that proposed scheme gives guaranteed QoS for different application data and gives a noticeable performance in terms of energy analysis and lifetime of the network.

Congestion control protocol for wireless sensor networks handling prioritized heterogeneous traffic

Heterogeneous applications could be assimilated within the same wireless sensor network with the aid of modern motes that have multiple sensor boards on a single radio board. Different types of data generated from such types of motes might have different transmission characteristics in terms of priority, transmission rate, required bandwidth, tolerable packet loss, delay demands etc. Considering a sensor network consisting of such multi-purpose nodes, in this paper we propose Prioritized Heterogeneous Traffic-oriented Congestion Control Protocol (PHTCCP) which ensures efficient rate control for prioritized heterogeneous traffic. Our protocol uses intra-queue and inter-queue priorities for ensuring feasible transmission rates of heterogeneous data. It also guarantees efficient link utilization by using dynamic transmission rate adjustment. Detailed analysis and simulation results are presented along with the description of our protocol to demonstrate its effectiveness in handling prioritized heterogeneous traffic in wireless sensor networks.

Health Risk Assessment of Pesticide Residues via Dietary Intake of Market Vegetables from Dhaka, Bangladesh

The present study was designed to assess the health risk of pesticide residues via dietary intake of vegetables collected from four top agro-based markets of Dhaka, Bangladesh. High performance liquid chromatography with a photo diode array detector (HPLC-PDA) was used to determine six organophosphorus (chlorpyrifos, fenitrothion, parathion, ethion, acephate, fenthion), two carbamate (carbaryl and carbofuran) and one pyrethroid (cypermethrin) pesticide residues in twelve samples of three common vegetables (tomato, lady’s finger and brinjal). Pesticide residues ranged from below detectable limit (<0.01) to 0.36 mg/kg. Acephate, chlorpyrifos, ethion, carbaryl and cypermethrin were detected in only one sample, while co-occurrence occurred twice for fenitrothion and parathion. Apart from chlorpyrifos in tomato and cypermethrin in brinjal, all pesticide residues exceeded the maximum residue limit (MRL). Hazard risk index (HRI) for ethion (10.12) and carbaryl (1.09) was found in lady’s finger and tomato, respectively. Rest of the pesticide residues were classified as not a health risk. A continuous monitoring and strict regulation should be enforced regarding control of pesticide residues in vegetables and other food commodities.

A lightweight temperature scheduling routing algorithm for an implanted sensor network

Modern diagnosis system has been evolved to equip human being with advanced health-service. In vivo sensors have come up to contribute in this field with its support in miniature, complex operation as implanted in a human body. Implanted sensor solutions like artificial retina, pacemaker and implanted cardioverter defibrillators, insulin pump, glucose monitor — are remarkable inventions in medical science. But, these implanted sensor nodes exhibit temperature at packet transmission or processing time that can be dangerous for surrounding human tissues. With the advancement of wireless communication and sensor network technology, thermal aware routing algorithms have been proposed for this type of sensor network. But, these algorithms suffer from disadvantages like hotspot creation, computational complexity overhead or redundant hop traversal etc. We also have to consider energy constraints like limited battery life of this miniature form of sensor nodes. We have tried to solve these problems with lightweight event-based communication (publish-subscribe system) in this type of sensor network. We have proposed a lightweight temperature scheduling routing algorithm for this implanted sensor network. Proposed routing protocol is considered to schedule temperature in implanted sensor nodes deployed in the joint operation of cancer hyperthermia, radio-therapy and chemo-therapy.

A Capacity Aware Data Transport Protocol for Wireless Sensor Network

Wireless link capacity within a sensor network has direct impact on its performance and throughput. Due to dense sensor deployment, interference seems to be a key factor for varying radio link capacity and also for congestion at hot spot region. Thus it is important to handle interference while removing in-network hot spots. The main goal of this paper is to achieve maximum utilization of link capacity for each sensor node controlling congestion related packet losses. Therefore in this paper we proposed an interference and capacity aware data transport protocol for sensor networks which performs rate control over congested wireless links. Proposed approach identifies the congested links that exists in hot spots and then adapts data transmission rate of corresponding sensor nodes. Perception of radio link interferences i.e. intra-path and inter-path interferences are used to estimate the capacity of each link. Finally simulation outputs have demonstrated the effectiveness of the proposed task and showed a noticeable performance in terms of packet delivery ratio, packet delivery latency and sensors runtime buffer size.

nW-MAC: multiple wake-up provisioning in asynchronously scheduled duty cycle MAC protocol for wireless sensor networks

To reduce the energy cost of wireless sensor networks (WSNs), the duty cycle (i.e., periodic wake-up and sleep) concept has been used in several medium access control (MAC) protocols. Although these protocols are energy efficient, they are primarily designed for low-traffic environments and therefore sacrifice delay in order to maximize energy conservation. However, many applications having both low and high traffic demand a duty cycle MAC that is able to achieve better energy utilization with minimum energy loss ensuring delay optimization for timely and effective actions. In this paper, nW-MAC is proposed; this is an asynchronously scheduled and multiple wake-up provisioned duty cycle MAC protocol for WSNs. The nW-MAC employs an asynchronous rendezvous schedule selection technique to provision a maximum of n wake-ups in the operational cycle of a receiver. The proposed MAC is suitable to perform in both low- and high-traffic applications using a reception window-based medium access with a specific RxOp. Furthermore, per cycle multiple wake-up concept ensures optimum energy consumption and delay maintaining a higher throughput, as compare to existing mechanisms. Through analysis and simulations, we have quantified the energy-delay performance and obtained results that expose the effectiveness of nW-MAC.

A Density Based Clustering for Node Management in Wireless Sensor Network

This paper represents a new clustering approach for wireless sensor network. It is a decentralized algorithm having the topology control information in each sensor node. A post leader selection algorithm is acted upon each of the clusters just after their formation. Experimental validation shows that the proposed scheme is an efficient approach for sensor node management.

A load-aware energy-efficient and throughput-maximized asynchronous duty cycle MAC for wireless sensor networks

Being a pivotal resource, conservation of energy has been considered as the most striking issue in the wireless sensor network research. Several works have been performed in the last years to devise duty cycle based MAC protocols which optimize energy conservation emphasizing low traffic load scenario. In contrast, considering the high traffic situation, another research trend has been continuing to optimize both energy efficiency and channel utilization employing rate and congestion control at the MAC layer. In this paper, we propose A Load-aware Energy-efficient and Throughput-maximized Asynchronous Duty Cycle MAC (LET-MAC) protocol for wireless sensor networks to provide an integrated solution at the MAC layer considering both the low-and high-traffic scenario. Through extensive simulation using ns-2, we have evaluated the performance of LET-MAC. LET-MAC achieves significant energy conservation during low traffic load (i.e., no event), compared to the prior asynchronous protocol, RI-MAC, as well as attains optimal throughput through maximizing the channel utilization and maintains lower delay in regard to the CSMA/CA-like protocol during a high volume of traffic (i.e., when an event occurs).

An approach for congestion control in sensor network using priority based application

Congestion causes packet loss which in turn drastically decreases network performance and throughput. As sensors are energy constraint so it is a decisive task to detect congestion and perform congestion control. Additionally, varieties of application have different requirement (i.e. delay, link utilization, and packet loss). In this paper we proposed an application priority based rate control algorithm to mitigate congestion in sensor network. This approach also maintains an interactive queue management scheme so that requirements of different application can be fulfilled. To ensure varieties application priority, concept of intra queue priority and inter queue priority are evolved. Node priority based hop by hop rate adjustment is also proposed here to ensure high link utilization. Finally experimental outputs have demonstrated the effectiveness of this task and show a noticeable performance in terms of energy analysis and throughput of the network.