Application of Wireless Sensor Networks for Indoor Temperature Regulation

International audienceWireless sensor networks take a major part in our everyday lives by enhancing systems for home automation, healthcare, temperature control, energy consumption monitoring, and so forth. In this paper we focus on a system used for temperature regulation for residential, educational, industrial, and commercial premises, and so forth. We propose a framework for indoor temperature regulation and optimization using wireless sensor networks based on ZigBee platform. This paper considers architectural design of the system, as well as implementation guidelines. The proposed system favors methods that provide energy savings by reducing the amount of data transmissions through the network. Furthermore, the framework explores techniques for localization, such that the location of the nodes can be used by algorithms that regulate temperature settings

Tree TDMA MAC Algorithm Using Time and Frequency Slot Allocations in Tree-Based WSNs

In this paper, we propose a tree-based time division multiple access (Tree TDMA) media access control (MAC) algorithm based on the IEEE 802.15.4 PHY standard. The method involves the simultaneous use of two algorithms, a time slot allocation algorithm (TSAA) and a frequency slot allocation algorithm (FSAA), at low power consumption to support voice and data communication to solve the problems afflicting prevalent MAC protocols in tree topology networks. The TSAA first generates routing paths through the control channel in a super frame prior to transmitting packets, and allocates time slots for each node to transmit packets. The FSAA then allocates frequencies to each path according to the routing paths generated following its application. The overhearing problem and the funneling effect in TDMA as well as carrier sense multiple access with collision avoidance (CSMA/CA) MACs are resolved by these two algorithms because a given node and its neighbors are orthogonal in terms of time and frequency. The problem of inter-node synchronization is addressed by periodically sending a beacon from higher to lower nodes, and the issue of low power is solved by leaving unsigned time slots in an idle state. To test the effectiveness of the proposed algorithm, we used a MATLAB simulation to compare its performance with that of contention-based CSMA MAC and non-contention-based TreeMAC in terms of network throughput, network delay, energy efficiency, and energy consumption. We also tested the performance of the algorithms for increasing number of nodes and transmission packets in the tree topology network.This work was supported by the ICT R&D Program of MSIP/IITP. [B0126-16-1018, The IoT Platform for Virtual Things, Distributed Autonomous Intellgence and Data Federation/Analysis

Green Cellular Networks: A Survey, Some Research Issues and Challenges

Energy efficiency in cellular networks is a growing concern for cellular operators to not only maintain profitability, but also to reduce the overall environment effects. This emerging trend of achieving energy efficiency in cellular networks is motivating the standardization authorities and network operators to continuously explore future technologies in order to bring improvements in the entire network infrastructure. In this article, we present a brief survey of methods to improve the power efficiency of cellular networks, explore some research issues and challenges and suggest some techniques to enable an energy efficient or "green" cellular network. Since base stations consume a maximum portion of the total energy used in a cellular system, we will first provide a comprehensive survey on techniques to obtain energy savings in base stations. Next, we discuss how heterogeneous network deployment based on micro, pico and femto-cells can be used to achieve this goal. Since cognitive radio and cooperative relaying are undisputed future technologies in this regard, we propose a research vision to make these technologies more energy efficient. Lastly, we explore some broader perspectives in realizing a "green" cellular network technologyComment: 16 pages, 5 figures, 2 table

A Feedback Approach for QoS-Enhanced MAC in Wireless Sensor Network

WSN as well as Wireless Multimedia Sensor Network (WMSN) has demands for QoS provision and differentiated service. The various types of data, such as video, voice, and network management, need to be periodically or best-effect transmitted. Since MAC layer forces the final physical medium accessing, it is the best choice to implement the QoS support for efficiency. This paper addresses the problem of QoS support in WSN from a renewed view of control theory and proposes FD-MAC architecture. By means of CSMA/CA, FD-MAC dynamically adjusts contention widow size according to the MAC frames’ priorities and their actual QoS metrics. The architecture can be modeled as a linear time-invariant system by system identification, and Least-Beat controller is designed to drive the system output to the desired value, which means the ratio of actual QoS metrics can be controlled to a prefixed value. The higher priorities enjoy a comparatively lower node-to-node delay while the lower priorities can still operate without being oversacrificed