ZigBee Middleware Development
ZigBee Middleware is a control software that offers an effective control over ZigBee networks for dynamic load balancing, better resources utilization, and increased reliability. It provides a global view of entire network that allows real-time monitoring of network traffic for avoiding hot spots and reporting vital node information. In addition, it implements certain security related functions such as calculation of device keys and distribution of field key. ZigBee control software resides between ZigBee stack and application profiles and acts as an interface between the two layers while offering added functionality of resource management and operational control.
Background & Objective: ZigBee is short-range multi-hop wireless mesh networking in diverse environments such as industrial, commercial, home, environmental monitoring, and military applications. Distributed algorithmic approach of ZigBee, however, introduces important limitations on its performance. Embedded address assignment and its automatic route discovery, despite being useful features, can result in uneven use of network resources. Moreover, a lack of real-time status reporting can cause significantly higher packet drop rate if some nodes start encountering operational problems. Useful node information, such as current battery level, packet loss rate, and average traffic delay, is not reported or leveraged in ZigBee specification. Our ZigBee middleware aims at addressing these limitations. While it can be deployed in diverse applications, the initial target systems are home automation, commercial building automation, and AMR.
Technical Discussion: ZigBee uses IEEE 802.15.4 PHY/MAC and defined its network layer, APS/ZDO sub-layers, and several profiles. Our middleware resides above ZDO but below application profiles. It follows a modular approach for a robust and fault tolerant control. It operates in two modes, one for host device, which acts as a controller, and another for regular ZigBee nodes. The host acts as a hub for object associations and message reflections. It creates virtual nodes and objects corresponding to the real ones in the network. All application commands pass through the host and all state changes in real objects are notified to it as well. The host allows primitives for model translation that may be performed while forwarding commands across device classes.
Future Direction: MERL will continue working on ZigBee based value added systems.
Contacts:
Ghulam Bhatti
Jinyun Zhang
Technology Area: Digital Communications
Modification Date: September 14, 2007
