Techniques for mitigating congestion in wireless sensor networks

Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, February 2005.Includes bibliographical references (p. 99-105).Network congestion occurs when offered traffic load exceeds available capacity at any point in a network. In wireless sensor networks, congestion causes overall channel quality to degrade and loss rates to rise, leads to buffer drops and increased delays (as in wired networks), and tends to be grossly unfair toward nodes whose data has to traverse a larger number of radio hops. Congestion control in wired networks is usually done using end-to-end and network-layer mechanisms acting in concert. However, this approach does not solve the problem in wireless networks because concurrent radio transmissions on different "links" interact with and affect each other, and because radio channel quality shows high variability over multiple time-scales. In this thesis, we examine three techniques that span different layers of the traditional protocol stack: hop-by-hop flow control, rate limiting source traffic when transit traffic is present, and a prioritized medium access control (MAC) protocol. We implement these techniques and present experimental results from a 55-node in-building wireless sensor network. We demonstrate that the combination of these techniques can improve network efficiency by a factor of three under realistic workloads.by Bret Warren Hull.S.M

A Trust Based Fuzzy Algorithm for Congestion Control in Wireless Multimedia Sensor Networks (TFCC)

Network congestion has become a critical issue for resource constrained Wireless Sensor Networks (WSNs), especially for Wireless Multimedia Sensor Networks (WMSNs)where large volume of multimedia data is transmitted through the network. If the traffic load is greater than the available capacity of the sensor network, congestion occurs and it causes buffer overflow, packet drop, deterioration of network throughput and quality of service (QoS). Again, the faulty nodes of the network also aggravate congestion by diffusing useless packets or retransmitting the same packet several times. This results in the wastage of energy and decrease in network lifetime. To address this challenge, a new congestion control algorithm is proposed in which the faulty nodes are identified and blocked from data communication by using the concept of trust. The trust metric of all the nodes in the WMSN is derived by using a two-stage Fuzzy inferencing scheme. The traffic flow from source to sink is optimized by implementing the Link State Routing Protocol. The congestion of the sensor nodes is controlled by regulating the rate of traffic flow on the basis of the priority of the traffic. Finally we compare our protocol with other existing congestion control protocols to show the merit of the work.Comment: 6 pages, 5 figures, conference pape

Wireless Sensor Networks: Challenges Ahead

The aim of this paper is to analyze the different Wireless Sensor Network (WSN) transport protocols byidentifying various experimental parameters in order to undertake a comparative evaluation. To build the groundwork, we first discuss the generic design for a transport protocol based on three key concepts; congestion control, reliability support and priority support. The basis of this design was developed by assessing several aspects of numerous transport protocols. However they all using different set of parameters and settings and hence it is difficult to benchmark one against the other. In this paper, we discuss the simulation settings like packet size, number of exploited sensors and their distribution in the field, buffer size, coverage area and power levels

Priority based Congestion Control Mechanism in Multipath Wireless Sensor Network

Wireless Sensor Network (WSN) is a network composed of distributed autonomous devices using sensors. Sensor nodes send their collected data to a determined node called Sink. The sink processes data and performs appropriate actions. Nodes using routing protocol determine a path for sending data to sink. Congestion occurs when too many sources are sending too much of data for network to handle. Congestion in a wireless sensor network can cause missing packets, long delay, overall channel quality to degrade, leads to buffer drops. Congestion control mechanism has three phases, namely congestion detection, congestion notification and congestion control. In this paper is propose two bit binary notification flag to notify the congested network status for implicit congestion detection. For congested network status, we propose a priority based rate adjustment technique for controlling congestion in link level. Congested packet will be distributed equally to the child node to avoid packet loss and transition delays based on technique. Furthermore, this technique allocates the priority of many applications simultaneously running on the sensor nodes, which route is own data as well as the data generated from other sensor nodes. The results show that the proposed technique achieves better normalized throughput and total scheduling rate with the avoiding packet loss and delay

Performance evaluation of different transport layer protocols on the IEEE 802.11 and IEEE 802.15.4 MAC/PHY layers for WSN

Wireless Sensor Networks (WSN) has gathered lot of attention from the research community lately. Among other WSN communication protocols, transport layer protocol plays a significant role in maintaining the node?s energy budget. In this context we have carried out extensive testing of various transport protocols using IEEE 802.11, IEEE 802.15.4 MAC/PHY protocol and Ad hoc On-Demand Distance Vector Routing (AODV) routing agent for WSN having multi-hop ad-hoc and WPAN network topology. The main contribution of this paper is to find out the dependency of Transport layer on MAC layer. Simulation results indicate that the underlying MAC/PHY layer protocol along with Transport layer protocol plays a vital role in achieving the high throughput, low latency and packet loss rate in WSN. For IEEE 802.11 with RTS/CTS ON high throughput, low packet drop rate and increased end-to-end packet delay is observed. While for IEEE 802.15.4 similar behavior as for IEEE 802.11 (except for UDP) but with improved power efficiency is observed. This has led the foundation for the future development of the proposed cross layered energy efficient transport protocol for multimedia application

Predictive Congestion Control MAC Protocol for Wireless Sensor Networks

Available congestion control schemes, for example transport control protocol (TCP), when applied to wireless networks results in a large number of packet drops, unfairness with a significant amount of wasted energy due to retransmissions. To fully utilize the hop by hop feedback information, a suite of novel, decentralized, predictive congestion control schemes are proposed for wireless sensor networks in concert with distributed power control (DPC). Besides providing energy efficient solution, embedded channel estimator in DPC predicts the channel quality. By using the channel quality and node queue utilizations, the onset of network congestion is predicted and congestion control is initiated. Stability of the hop by hop congestion control is demonstrated by using a Lyapunov-based approach. Simulation results show that the proposed schemes result in fewer dropped packets than a network without the hop-by-hop congestion control, better fairness index and network efficiency, higher aggregate throughput, and smaller end-to-end delays over the other available schemes like IEEE 802.11 protocol

Wireless Sensor Network Transport Protocol - A State of the Art

In this article, we present a survey of Wireless Sensor Networks (WSNs) existing Transport Protocols. Wehave evaluated the design concepts of different protocols based on congestion control, reliability support and source traffic priority support. Then we draw the concluding remarks, while highlighting up-and-coming research challenges for WSN transport protocols, which should be addressed further in prospective designs

Route Aware Predictive Congestion Control Protocol for Wireless Sensor Networks

Congestion in wireless sensor networks (WSN) may lead to packet losses or delayed delivery of important information rendering the WSN-based monitoring or control system useless. In this paper a routing-aware predictive congestion control (RPCC) yet decentralized scheme for WSN is presented that uses a combination of a hop by hop congestion control mechanism to maintain desired level of buffer occupancy, and a dynamic routing scheme that works in concert with the congestion control mechanism to forward the packets through less congested nodes. The proposed adaptive approach restricts the incoming traffic thus preventing buffer overflow while maintaining the rate through an adaptive back-off interval selection scheme. In addition, the optimal routing scheme diverts traffic from congested nodes through alternative paths in order to balance the load in the network, alleviating congestion. This load balancing of the routes will even out the congestion level throughout the network thus increasing throughput and reducing end to end delay. Closed-loop stability of the proposed hop-by-hop congestion control is demonstrated by using the Lyapunov-based approach. Simulation results show that the proposed scheme results in reduced end-to-end delays

GCCP - NS: Grid based Congestion Control protocol with N-Sinks in a Wireless Sensor Network

Wireless Sensor Networks (WSN) have been a current trend in the research field and has many issues when there are multiple mobile sinks. Data dissemination gets critical as their locations have to be repeatedly updated and results in huge consumption of the restricted battery supply in sensor nodes. In this paper, we propose GCCP – NS, a grid based congestion control protocol with N –sinks that solves the data dissemination problem leading to congestion. We construct a dual level grid structure to trail the locations of all the source nodes that reports the information to the mobile sinks by monitoring the network in a hierarchical manner. As an added advantage, it aids in data dissemination based on query flooding from the mobile sinks using quorum based method within each cell in the grid and avoids congestion in an effective manner. Simulation results show that our proposed protocol outperforms the other schemes in terms of packet delivery ratio, energy expenditure and throughput