Microwave Engineering Europe - January/February 2008 - (Page 21)

WIRELESS SENSOR NETWORKS — ZigBee 21 operating channels, compared with a single channel for some competing lower-frequency proprietary systems. ZigBee PRO’s Frequency Agility function (also optional with the ZigBee Feature Set) makes utilization of these channels easier. When a ZigBee network is initiated, the node forming the network scans for an available channel with the least existing trafﬁc or noise. Over time, if the busyness of the chosen channel increases or a new interference source emerges, the Frequency Agility function may be used by the application to scan for a better channel and seamlessly “move” the entire network to the new channel. This allows the network to adapt to changing environments over months or years. ZigBee networks use the IEEE 802.15.4 PAN ID as their basic identiﬁer, allowing different logical ZigBee networks even on the same channel. However, if two networks overlap with the same PAN ID (such as devices using the same defaults), confusion may result. ZigBee PRO provides automatic detection and resolution of conﬂicting PAN IDs, including application notiﬁcation. Figure 2: Through shared many-toone routes and source routing, less routing table space is used. Improved security: New options for more secure communications Since the beginning, ZigBee has included integrated security functions leveraging AES128 encryption for protecting network communications. ZigBee PRO now provides signiﬁcant enhancements to the security choices available for secure wireless networks. ZigBee PRO offers two different security modes: “Standard” security and “High” Security. Standard security extends and is functionally compatible with the “Residential” security mode offered by the ZigBee Feature Set and the 2006 ZigBee speciﬁcation. In this mode, all network communications can be encrypted using the AES128 algorithm using a single network-wide “network key”. Devices in the network may have the network key pre-conﬁgured, individually commissioned, or distributed by a centralized trust center. The ZigBee PRO Standard Security mode further provides for the additional encryption Microwave Engineering ● January/February 2008 ● www.mwee.com 019_020_021_022_MWEE.indd 21 24/01/08 11:14:29 http://www.lpkf.com http://www.lpkf.com http://www.mwee.com

Table of Contents Feed for the Digital Edition of Microwave Engineering Europe - January/February 2008

Microwave Engineering Europe - January/February 2008 Contents News Comment Radio: Raising the Bar for the Radio: Making 802.11n Work Cover Feature: The RF-System-In-Package Trend - Efficient Design with Advanced Design System 2008 Wireless Sensor Networks: The Zigbee PRO Feature Set: More of a Good Thing Very Fast Measurements of Wireless Devices with Small Antennas in Reverberation Chambers WiMAX Update 2008 Bridging the Gap from the CMOS DSP to the Antenna in OFDM Systems Products Calendar

Microwave Engineering Europe - January/February 2008

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