Continuation of Wireless Sensor Network Architecture for Monitoring and Control in Buildings

PI: Myung Lee, the City College of New York


Executive Abstract

In the U.S., buildings consume 70% of all electricity, up to 50% of which is wasted. Thus, the one of the key thrusts of planning sustainable buildings is the resource conservation while being environmentally sensible. Many components of sustainable buildings are tightly networked to monitor and control to achieve the optimal conditions for occupants of the buildings and energy expenditure. Thousands of sensors can monitor everything from motion and temperature to humidity, precipitation, occupancy and light. The monitored information will be used to control HVAC, light, electric motors, water valves, etc.

Wireless Sensor Network (WSN) has been serving to network all these monitoring and control devices. During the Project Year 1, we have been investigating a novel WSN architecture that can meet a diverse range of quality of service requirements such as time delay, throughput, and reliability anticipated not only from building applications but other time critical applications as well as large scale sensor network applications. In particular, we have developed a tree-based WSN routing algorithm utilizing multi-channel and multi-timeslot framework specified in the IEEE Standard 802.15.4e MAC protocol published in 2011. Given an e2e delay, simulations show that the proposed algorithm meets the given requirement. The optimal tree routing was developed by applying metaheuristic optimization techniques - Simulated Annealing (SA) and Particle Swarm Optimization (PSO) - which were shown to be scalable. Encouraged by the favorable performance by the PSO algorithm, we are extending the tree architecture to design a general mesh WSN routing to support information transmission from any node to any node. By the end of the Year 1, we plan to complete the algorithm design for WSN mesh routing architecture.

In this proposal for Year 2, we plan to focus on the implementation of unicast mesh routing algorithm developed during the Year 1. A challenge is the real channel environment often infested by interferences from the homogeneous devices as well as heterogeneous devices sharing common bands like 2.4 GHz ISM band. Another hurdle is the synchronization of devices. As the optimal scheduling of multi-channel and multi-time slot frame assumes network-wide synchronization, we will also need to investigate various synchronization alternatives. Currently there is no commercially available off-the-shelf devises implemented IEEE 802.15.4e MAC; thus, we may need to find an alternative approach.

Objective 1: Development and Implementation of unicast mesh algorithm
Objective 2: Proof of Concept Demo for a building application