Congestion control protocols in wireless sensor networks: A survey

The performance of wireless sensor networks (WSN) is affected by the lossy communication medium, application diversity, dense deployment, limited processing power and storage capacity, frequent topology change. All these limitations provide significant and unique design challenges to data transport control in wireless sensor networks. An effective transport protocol should consider reliable message delivery, energy-efficiency, quality of service and congestion control. The latter is vital for achieving a high throughput and a long network lifetime. Despite the huge number of protocols proposed in the literature, congestion control in WSN remains challenging. A review and taxonomy of the state-of-the-art protocols from the literature up to 2013 is provided in this paper. First, depending on the control policy, the protocols are divided into resource control vs. traffic control. Traffic control protocols are either reactive or preventive (avoiding). Reactive solutions are classified following the reaction scale, while preventive solutions are split up into buffer limitation vs. interference control. Resource control protocols are classified according to the type of resource to be tuned. © 2014 IEEE

Dynamic Diffusion for Congestion Avoidance in Wireless Sensor Networks

Wireless Sensor Networks (WSNs) are employed for either continuous monitoring or event detection in the target area of interest. In event-driven applications, it is critical to report the detected events in the area, and with sudden bursts of traffic possible due to spatially-correlated events or multiple events, the data loss due to congestion will result in information loss or delayed arrival of the sensed information. Congestion control techniques detect congestion and attempt to recover from packet losses due to congestion, but they cannot eliminate or prevent the occurrence of congestion. Congestion avoidance techniques employ proactive measures to alleviate future congestion using parameters like queue length, hop count, channel conditions, and priority index. However, maintaining and processing such information becomes a significant overhead for the sensor nodes and degrades the performance of the network. We propose a congestion avoidance MAC protocol that uses the queue buffer length of the sensor nodes to estimate the congestion and diffuse traffic to provide a congestion-free routing path towards the base station. This protocol provides event reporting, packet delivery ratio, by dynamically diffusing the traffic in the network using multiple forwarders in addition to backup forwarding. We used the standard Network Simulator (NS2) to evaluate the performance of our protocol. Results show that our protocol significantly improves event reporting in terms of packet delivery ratio, throughput, and delay by avoiding congestion while diffusing the traffic effectively

Congestion Mitigation by Traffic Dispersion in Wireless Sensor Networks

Wireless sensor networks (WSNs) are event-based systems that rely on the collective effort of several sensor nodes. When all nodes in an area sense an event and transmit that data, it causes sudden traffic bursts, which are spatially-correlated and lead to network congestion. Congestion can cause an increase in the amount of data loss, energy consumption, delay data transmission, and hinder network performance. To improve performance of event-driven applications, there arises a need for protocols that can reduce congestion and energy consumption. Existing protocols for sensing multiple events either handle congestion control or spatially-correlated contention, but not both, which can degrade network performance in terms of packet delivery ratio, latency, and energy consumption. Motivated primarily by the challenge to improve the performance of event-driven applications, we propose an energy efficient protocol to mitigate congestion that improves data delivery and reduces latency. This protocol mitigates congestion by dispersing network traffic using a forwarder selection mechanism that forces event reports from different nodes to disperse along different paths to the base station. Our protocol also reduces spatially-related contention by partitioning the sensors into different groups. All the sensors in a particular group cover the region of interest together, and these groups are scheduled in such that only one group is active to transmit the data at any given time. We implemented our protocol using the NS2 simulator for evaluating its performance. Results show that our protocol has significant improvement in the packet-delivery ratio, latency, and energy savings

A perennial simulation framework for integrated crisis management studies

Ph.DDOCTOR OF PHILOSOPH

A Multievent Congestion Control Protocol for Wireless Sensor Networks

Wireless sensor networks are application-dependent networks. An application may require general event region information, per-node event region information, or prioritized event information in case of multiple events. All event flows are subject to congestion in wireless sensor networks. This is due to the sudden impulse of information flow from a number of event nodes to a single destination. Congestion degrades system throughput and results in energy loss of nodes. In this paper, we present a multievent congestion control protocol (MCCP) for wireless sensor networks. MCCP supports multiple event reporting modes, that is, general event reporting, per-node fair event reporting, and prioritized multiple event reporting. MCCP efficiently mitigates congestion and provides output according to selected event reporting mode. MCCP uses hop-by-hop packet delivery time and buffer size as the basic metrics for congestion detection. Moreover, we introduce a schedule-based scheme at the transport layer for rate assignment and ordered delivery of event packets to underlying routing layer. This helps to avoid packet collisions and increases the packet delivery ratio even in high densities. Detailed simulation analysis confirms that MCCP decreases packet drops and provides high packet delivery ratio (above 90%) for multiple event reporting modes. Copyright (C) 2008 Faisal B. Hussain et al