The design of a simple energy efficient routing protocol to improve wireless sensor network lifetime

The number of potential applications for wireless sensor networks is immense. These networks may consist of large numbers of low cost, low power, disposable sensor nodes that can be deployed inside or close to phenomena to be monitored. The nature of these networks necessitates specific design requirements, of which energy efficiency is paramount. The limited available energy of sensor nodes is mainly drained during communication and computational processing. An energy efficient routing protocol can limit the number of message transmissions and the computational complexity of finding routing paths. Many routing protocols have been proposed for wireless sensor networks. Most of them are computationally complex, require a large number of messages to be transmitted or require that sensor nodes possess certain hardware capabilities in order to function. The objective of this dissertation was to develop a Simple Energy Efficient Routing (SEER) protocol for wireless sensor networks that is computationally simple, reduces the number of transmitted messages and does not impose any hardware prerequisites. The new routing protocol, which was developed during this research, uses a flat network structure for scalability and source initiated communication along with event-driven reporting to reduce the number of message transmissions. Computational simplicity is achieved by using a simple method for routing path selection. The SEER protocol selects the next hop for a message by choosing a neighbour that has a smaller or equal hop count to the current node. If multiple neighbours satisfy this requirement, the neighbour with the highest remaining energy is chosen as the next hop. Each node in the network has a table containing the hop count and remaining energy of each of its neighbours. Periodic messages sent through the network update these neighbour tables. SEER uses a novel approach to select the next hop of a message during routing. The protocol increases the lifetime of the network dramatically, compared to other similar routing protocols. This improvement is directly related to the reduction in the number of transmissions made by each node. The simplicity of the protocol reduces the required computational processing compared to other protocols, and at the same time makes this one of the few available protocols that does not impose hardware requirements on nodes in order to function.Dissertation (MEng (Computer Engineering))--University of Pretoria, 2007.Electrical, Electronic and Computer Engineeringunrestricte

Multimedia Streaming through Wireless Networks

An overview of wireless networks, cross-layer optimization techniques, and advances in wireless LAN technologies is presented. This paper presents a scalable and adaptive system-level approach to wireless multimedia in the emerging, Proactive Enterprise computing environment. A Distributed Network Information Base with Service Agents at each node is proposed to enable network-wide, proactive adaptation with adaptive routing and end-to-end Quality of Service (QoS) management. The paper suggests that a combination of technological advancements in emerging wireless networks, node-level cross-layer optimizations, and the proposed distributed cross-node system-level architecture are all required to efficiently scale and adapt wireless multimedia in the current market

Mutation Based Hybrid Routing Algorithm for Mobile Ad-hoc Networks

Mobile Adhoc NETworks (MANETs) usually present challenges such as a highly dynamic topology due to node mobility, route rediscovery process, and packet loss. This leads to low throughput, a lot of energy consumption, delay and low packet delivery ratio. In order to ensure that the route is not rediscovered over and over, multipath routing protocols such as Adhoc Multipath Distance Vector (AOMDV) is used in order to utilize the alternate routes. However, nodes that have low residual energy can die and add to the problem of disconnection of network and route rediscovery. This paper proposes a multipath routing algorithm based on AOMDV and genetic mutation. It takes into account residual energy, hop count, congestion and received signal strength for primary route selection. For secondary path selection it uses residual energy, hop count, congestion and received signal strength together with mutation. The simulation results show that the proposed algorithm gives better performance results compared to AOMDV by 11% for residual energy, 45% throughput, 3% packet delivery ratio, and 63% less delay

High-rate UWB and 60 GHz communications

In this chapter, two technologies for high data-rate communications systems for wireless personal area networks (WPANs) are discussed. Namely, the ultrawideband (UWB) technology that operates in the 3.1-10.6 GHz band and the millimeter wave (MMW) technology (also called 60 GHz radio) that can use the 57-64 GHz band in most parts of the world are considered. First, a generic overview is given and various application scenarios are discussed. Then, the ECMA standard for high-rate UWB systems is studied. Finally, two standards for the 60 GHz MMW radio are investigated.Overview and application scenarios In order to realize high-speed communications systems with low power consumption, signals with very large bandwidths need to be employed. One way of designing such communications systems is to use UWB signals as an underlay technology by utilizing all or part of the frequency spectrum between 3.1 and 10.6 GHz [1-3]. According to the US Federal Communications Commission (FCC), a UWB signal is defined as having an absolute bandwidth of at least 500 MHz or a relative (fractional) bandwidth of larger than 20% [3-4].In order not to cause any adverse effects on other wireless systems in the same frequency band, such as IEEE 802.11a wireless local area networks (WLANs), certain power emission limits are imposed on UWB devices by regulatory authorities, such as the FCC in the USA [3] and the Electronic Communications Committee (ECC) in Europe [5]. © Cambridge University Press 2011

Aggregated Packet Transmission in Duty-Cycled WSNs: Modeling and Performance Evaluation

[EN] Duty cycling (DC) is a popular technique for energy conservation in wireless sensor networks (WSNs) that allows nodes to wake up and sleep periodically. Typically, a single-packet transmission (SPT) occurs per cycle, leading to possibly long delay. With aggregated packet transmission (APT), nodes transmit a batch of packets in a single cycle. The potential benefits brought by an APT scheme include shorter delay, higher throughput, and higher energy efficiency. In the literature, different analytical models have been proposed to evaluate the performance of SPT schemes. However, no analytical models for the APT mode on synchronous DC medium access control (MAC) mechanisms exist. In this paper, we first develop a 3-D discrete-time Markov chain (DTMC) model to evaluate the performance of an APT scheme with packet retransmission enabled. The proposed model captures the dynamics of the state of the queue of nodes and the retransmission status and the evolution of the number of active nodes in the network, i.e., nodes with a nonempty queue. We then study the number of retransmissions needed to transmit a packet successfully. Based on the observations, we develop another less-complex DTMC model with infinite retransmissions, which embodies only two dimensions. Furthermore, we extend the 3-D model into a 4-D model by considering error-prone channel conditions. The proposed models are adopted to determine packet delay, throughput, packet loss, energy consumption, and energy efficiency. Furthermore, the analytical models are validated through discrete-event-based simulations. Numerical results show that an APT scheme achieves substantially better performance than its SPT counterpart in terms of delay, throughput, packet loss, and energy efficiency and that the developed analytical models reveal precisely the behavior of the APT scheme.This work was supported in part by the EU FP7-PEOPLE-IRSES Program under Grant 247083 (Project S2EuNet). The work of J. Martinez-Bauset was supported in part by the Ministry of Economy and Competitiveness of Spain under Grant TIN2013-47272-C2-1-R. The work of M. A. Weitnauer was supported in part by the U.S. National Science Foundation under Grant CNS-1017984.Guntupalli, L.; Martínez Bauset, J.; Li, FY.; Weitnauer, MA. (2017). Aggregated Packet Transmission in Duty-Cycled WSNs: Modeling and Performance Evaluation. IEEE Transactions on Vehicular Technology. 66(1):563-579. https://doi.org/10.1109/TVT.2016.2536686S56357966

Cross-layer design for network performance optimization in wireless networks

In this dissertation, I use mathematical optimization approach to solve the complex network problems. Paper l and paper 2 first show that ignoring the bandwidth constraint can lead to infeasible routing solutions. A sufficient condition on link bandwidth is proposed that makes a routing solution feasible, and then a mathematical optimization model based on this sufficient condition is provided. Simulation results show that joint optimization models can provide more feasible routing solutions and provide significant improvement on throughput and lifetime. In paper 3 and paper 4, an interference model is proposed and a transmission scheduling scheme is presented to minimize the end-to-end delay. This scheduling scheme is designed based on integer linear programming and involves interference modeling. Using this schedule, there are no conflicting transmissions at any time. Through simulation, it shows that the proposed link scheduling scheme can significantly reduce end-to-end latency. Since to compute the maximum throughput is an NP-hard problem, efficient heuristics are presented in Paper 5 that use sufficient conditions instead of the computationally-expensive-to-get optimal condition to capture the mutual conflict relation in a collision domain. Both one-way transmission and two-way transmission are considered. Simulation results show that the proposed algorithms improve network throughput and reduce energy consumption, with significant improvement over previous work on both aspects. Paper 6 studies the complicated tradeoff relation among multiple factors that affect the sensor network lifetime and proposes an adaptive multi-hop clustering algorithm. It realizes the best tradeoff among multiple factors and outperforms others that do not. It is adaptive in the sense the clustering topology changes over time in order to have the maximum lifetime --Abstract, page iv