Wireless sensor networks (WSN) are the base of the Internet of Things (IoT) that all together give rise to the smart city. These WSNs consist of several sensors, which are densely distributed to observe physical or environmental conditions, like humidity, temperature, light intensity, and gas concertation. The sensors reading data are transmitted to the network coordinator, the IP-gateway, which is at the heart of the wireless network. Many monitoring systems are to be found in the literature with generic designs and with the output of algorithms that runs on the given systems. In this paper, we review the related work on monitoring systems and propose the framework based on WSN to sense the readings from the environment to transmit and store in the cloud for calling on the handheld devices when required by the single or multiple users. A real sensor nodes-based experimental testbed is implemented in order to study the scalability, adaptability, and sustainability of the novel WSN-based environmental monitoring framework.
Mobility has now a crucial requirement for wireless comm unication. Handover is one of the major tasks that are used to support continuous transmission for a mobile terminal into different radio coverage area. Optimizing the existing handover protocol requires integrating new functionalities. This work focuses on presenting and optimizing handover algorithm. We analyze hand over time in wireless local area networks based on the IEEE 802.11 b MAC protocol. In fact, scan phase is the main contributor to the hand over time. Then, we propose a handover model which replaces a scan phase by a positioning process. This model is able to select the suitable access point (AP) based on the shortest distance far from the mobile terminal (MT). Proposed Handover allows a mobile user to reacting quickly to decide about to which access point to connect. Simulation results show that the proposed model provides gains in term of delays and Handover success in various scenarios Ke y words:IEEE 802.11, Handover, positioning, Latenc y .
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.