#medium access control

Read the full paper at: http://www.scirp.org/journal/PaperInformation.aspx?PaperID=49946 DOI: 10.4236/wsn.2014.69019 Author(s) Juan Lu, Adrien Van Den Bossche, Eric Campo ABSTRACT Monitoring behaviour of the elderly and the disabled living alone has become a major public health problem in our modern societies. Among the various scientific aspects involved in the home monitoring field, we are interested in the study and the proposal of a solution allowing distributed sensor nodes to communicate with each other in an optimal way adapted to the specific application constraints. More precisely, we want to build a wireless network that consists of several short range sensor nodes exchanging data between them according to a communication protocol at MAC (Medium Access Control) level. This protocol must be able to optimize energy consumption, transmission time and loss of information. To achieve this objective, we have analyzed the advantages and the limitations of WSN (Wireless Sensor Network) technologies and communication protocols currently used in relation to the requirements of our application. Then we proposed a deterministic, adaptive and energy saving medium access method based on the IEEE 802.15.4 physical layer and a mesh topology. It ensures the message delivery time with strongly limited collision risk due to the spatial reuse of medium in the two-hop neighbourhood. EWW140925GJR This proposal was characterized by modelling and simulation using OPNET network simulator. Finally we implemented the proposed mechanisms on hardware devices and deployed a sensors network in real situation to verify the accuracy of the model and evaluate the proposal according to different test configurations. KEYWORDS Wireless Sensor Network, Medium Access Control, Quality of Service, Energy Saving, Mesh Topology, IEEE 802.15.4, Indoor Monitoring Application

The breathtaking success of the WDM technology in backbone networks also pushes the development and implementation of optical packet-switched WDM local and metropolitan area networks. Local and metropolitan area optical WDM networks are emerging as viable and cost-effective solutions for many telecommunication operators and service providers who have to face an extremely growing bandwidth demand and expensive additional fiber installation costs. Thus, the strong need for the development of novel high-speed architectures and protocols for such networks arises. In Optical Packet Access Protocols for WDM Networks, different basic and novel medium access control (MAC) protocols for WDM-based LANs/MANs, typically belonging to the group of single-hop networks, are proposed and analyzed. Thereby, solutions for the direct and efficient support of distinct Quality-of-Service (QoS) classes over the WDM transmission layer are provided. Optical Packet Access Protocols for WDM Networks Besides a comprehensive overview on the state-of-the-art photonic metro networks, highly dynamic reservation-based access protocols relying on the passive-star and the ring topology are presented while assuming the deployment of wavelength-tunable transceivers at the network nodes. Optical Packet Access Protocols for WDM Networks provides both a comprehensive survey on existing WDM local and metro lightwave systems and the design of novel highly efficient medium access control protocols with QoS support for such systems. Accordingly, this work is appropriate for communication and network engineers from both the academic and industrial world working in the field of optical communication networks, computer science, and communication engineering.