Faisal Bashir Hussain

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.

QoS in Wireless Multimedia Sensor Networks: A Layered and Cross-Layered Approach

The emergence of wireless multimedia sensor networks (WMSN) has given birth to several civilian as well as defense applications. Some of the interesting applications employing low cost sensor nodes to manipulate rich multimedia content include traffic monitoring, border surveillance, smart homes, environment and habitat monitoring. Unlike the traditional sensor networks which are aimed at maximizing network lifetime by decreasing energy utilization, the main objective of WMSNs is optimized delivery of multimedia content along with energy efficiency. Multimedia communications in WMSNs, has stringent delay and high bandwidth requirement as compared to scalar data transfer in WSNs. Fulfilling these constraints in resource and energy constrained WMSNs is a huge challenge. In WMSNs, each layer of the protocol stack is responsible and fully involved in providing QoS guarantees. There is a need for new schemes at each layer of the protocol stack- from advanced coding techniques that reduce encoder complexity and achieve maximum compression to dynamic routing and MAC protocols that provide service differentiation and reduce end-to-end latency. In wireless sensor networks, where all layers have dependency on each other, QoS guarantees are possible through the cross layer interaction of different layers. This paper gives an overview of the different existing layered schemes in WMSNs, followed by a discussion on the significance and efficiency gains that can be achieved from cross layer interactions in WMSNs along with the review of the existing cross layer approaches. Finally, we identify the open research issues which have not been adequately addressed so far.

Energy efficient routing protocol for zone based mobile sensor networks

Mobility in sensor networks has not only expanded the role of sensor networks but has also given a whole new dimension to all research areas. Extra vigilance and unique approaches are required to address the concerns raised due to mobility. Therefore, we present a novel zone based routing scheme that is modified from Adhoc Ondemand Distance Vector Routing protocol. Our protocol is not only efficient in reducing the amount of control information produced as a result of path finding but also capable of reducing network segment errors, such that routing information is always available in the underlying network. The results have shown that this scheme is efficient in case of low as well as high mobility scenarios due to our proposed zone based architecture.

Delay and link utilization aware routing protocol for wireless multimedia sensor networks

Wireless Multimedia Sensor Networks (WMSNs) consist of networks of interconnected devices involved in retrieving multimedia content, such as, video, audio, acoustic, and scalar data, from the environment. The goal of these networks is optimized delivery of multimedia content based on quality of service (QoS) parameters, such as delay, jitter and distortion. In multimedia communications each packet has strict playout deadlines, thus late arriving packets and lost packets are treated equally. It is a challenging task to guarantee soft delay deadlines along with energy minimization, in resource constrained, high data rate WMSNs. Conventional layered approach does not provide optimal solution for guaranteeing soft delay deadlines due to the large amount of overhead involved at each layer. Cross layer approach is fast gaining popularity, due to its ability to exploit the interdependence between different layers, to guarantee QoS constraints like latency, distortion, reliability, throughput and error rate. The paper presents a channel utilization and delay aware routing (CUDAR) protocol for WMSNs. This protocol is based on a cross-layer approach, which provides soft end-to-end delay guarantees along with efficient utilization of resources. Extensive simulation analysis of CUDAR shows that it provides better delay guarantees than existing protocols and consequently reduces jitter and distortion in WMSN communication.

Traffic-aware congestion control (TACC) for wireless multimedia sensor networks

Wireless multimedia sensor networks (WMSNs) have emerged as a revolutionary technology, that has shifted the focus of low power wireless sensor networks (WSNs). These networks are aimed at gathering and delivering both scalar and multimedia data from the environment. WMSNs inherit the miniature size, low power, low processing and short range wireless communication traits from WSNs. Addition of multimedia content in WMSNs demands fulfillment of various QoS parameters like low end-to-end delay, acceptable jitter rate, low packet loss rate and higher throughput. Over the past few years, considerable research efforts have been directed towards the fulfillment of these QoS requirements; by proposing new traffic-aware medium access and routing algorithms. However, the issues of rate adaptation and congestion control are still largely unexplored. Congestion in wireless networks is a major cause of packet loss resulting in degraded network performance. In WMSNs congestion is a common occurrence, due to the communication of high data rate, bursty video traffic over lossy wireless link. Therefore, it is critical to adjust the sending rate of source nodes based on network conditions. This work investigates the issue of rate adaptation and congestion control in WMSNs. A traffic-aware congestion control protocol (TACC) is proposed that operates on end-to-end principle at the transport layer. The proposed protocol uses burst loss information to detect congestion at the destination and directs source nodes to adjust reporting rate accordingly. The proposed protocol is evaluated using simulation analysis which shows significant improvement in terms of packet losses, end-to-end delay, packet delivery ratio and received picture quality.

Many-to-one congestion control scheme for densely populated WSNs

Many-to-one transport results in congestion in wireless sensor networks. This is due to the sudden impulse of information flow to a single destination. Greater the number of event reporting nodes greater will be the degree of congestion; considering fixed transmission power for nodes. Therefore an important factor in the design of a congestion control scheme is the density of the network. In this paper we present a new congestion control scheme based on hop-by-hop packet delivery time and buffer size. The new congestion control scheme is at the transport layer and uses a TDMA-like mechanism to optimally adjust the reporting rate of events. Detailed simulation analysis confirm that the proposed congestion control scheme decreases packet drops and provide high packet delivery ratio (above 90%) from even very dense event reporting regions.

A delay mitigation dynamic scheduling algorithm for the IEEE 802.15.4 based WPANs

The IEEE 802.15.4 is designed for low data rate low power wireless personal area networks (LR-WPANs). LR-WPANs are envisioned for a variety of wireless sensor applications: health monitoring, commercial, agriculture, home and industrial automation. A significant feature of IEEE 802.15.4 is the very low duty cycle operation to preserve sensor nodes energy. In this paper, we propose a delay mitigation dynamic scheduling algorithm (DMDSA) that adjusts super-frame structure. In DMDSA, the PAN coordinator adjusts both parameters beacon order (BO) and super-frame order (SO) concurrently based on different metrics: number of PAN source members, application defined data rate, observed end-to-end latency and receive ratio. These parameters are adjusted dynamically when delay is observed during communication. Detailed simulation analysis shows that DMDSA is capable of meeting applications delay requirements by dynamically scheduling the super-frame structure. As compared to IEEE 802.15.4, DMDSA decreases the latency of communication, increases the throughput, and increases network life time.

Coordinator Discovery and Association in Beacon-Enabled IEEE 802.15.4 Network

End devices in beacon-enabled IEEE 802.15.4 network rely on passive scan to find the coordinator for association. The latency of coordinator discovery depends on coordinators beacon interval length. If beacon interval is long then more time is required for successful discovery and vice versa. The latency of association message exchange in IEEE 802.15.4 is considerably high due to response wait time. It is the time during which the coordinator registers the device and assigns a network address. The overall time required for successful discovery and association is inadequate to support connectivity of mobile devices in short range IEEE 802.15.4 networks. To decrease this time, we propose a coordinator assisted passive discovery and association scheme for mobile end devices in IEEE 802.15.4 networks. The proposed scheme decreases the beacon interval of the coordinators that are close to mobile devices for prompt neighboring coordinator(s) discovery. Also, it eliminates the need for response wait time during association based on early registration mechanism. Simulation analysis shows that the proposed scheme ensures fast passive discovery and association with the coordinator, irrespective of beacon interval length.

Rank attack using objective function in RPL for low power and lossy networks

The Routing Protocol for Low power and lossy network (RPL) is recommended by Internet Engineering Task force (IETF) for IPv6 based Low Power Personal Area Network (6LoWPAN). RPL is a proactive routing protocol for Internet of Things (IoT) that has applications in smart homes, smart cities and smart world. RPL creates a Directed Acyclic Graph (DAG) of the network topology. Rank in a primitive construct in RPL and it defines the relative position of node within the DAG. It is used for topology formation, maintenance and prevention of loops in routing paths. Few internal attacks are identified in existing literatures which maliciously use the rank property within RPL networks. In this paper, we introduce a new rank attack in RPL networks that modifies Objective Function (OF) along with rank value. The OF is used by RPL nodes to select forwarding nodes based on application defined routing metric e. g., expected transmission count, residual energy etc. The proposed rank attack is more distractive in nature because the attacking node can easily force its neighboring nodes to route their data through the attacking node. Comprehensive simulation analysis has shown that the proposed rank attack can be used to introduce false routing path for decreasing network throughput and increasing latency of communication.

Survey of Dynamic Super-Frame Adjustment Schemes in Beacon-Enabled IEEE 802.15.4 Networks: An Application's Perspective

IEEE 802.15.4 targets low data rate communication with limited power devices and cheap wireless networking solutions. In recent years both industry and academia are attracted to IEEE 802.15.4 because of its applicability in wireless sensor networks and wireless body area networks. An important feature of IEEE 802.15.4 is its very low duty cycle operation for conserving energy consumption of sensor device. Super-frame structure of IEEE 802.15.4 defines the duty cycle of nodes. The super-frame structure is based on two parameters: beacon order (BO) and super-frame order (SO). The performance of an IEEE 802.15.4 network depends on the values of BO and SO. These values depict the energy consumption, throughput, node discovery and latency of communication. IEEE 802.15.4 uses fixed BO and SO values which can be carefully chosen to meet the network requirements. In this paper, an extensive survey of dynamic super-frame adjustment algorithms is presented. The survey focuses on beacon-enabled star topology of IEEE 802.15.4 and studies the impact of aforementioned algorithms for various applications. Also, the survey categorizes common IEEE 802.15.4 applications based on their requirements for super-frame adjustment. A brief simulation analysis is included in this survey to highlight the impact of BO and SO on the network performance.