Microwave Engineering Europe - March 2008 - (Page 34)

34 WIRELESS INFRASTRUCTURE between ANT with SenRcore and a ZigBeebased system from an established ZigBee supplier. (SensRcore conﬁgures the sensor at start-up with a ﬂash memory stored sensor proﬁle and the relevant ANT sensor communication protocol. ANT chips and modules equipped with SensRcore do not require an application host microcontroller.) The test comprised the implementation of a simple wireless security system using modules from each company Figure 1: Mesh networks are overly complex for most (see reference [1]). practical WSN applications. While the developers were experienced in embedded product design and wireless technologies they had no speciﬁc prior experience with either ANT or ZigBee – ensuring the comparison was balanced and unbiased. When it came to setting up the security network AuZone found that ZigBee took twice as long to conﬁgure as ANT’s technology (at 160.5 hrs compared to 83 hrs). And even then, the company commented that the ZigBee application was a “work in progress, as there were some outstanding issues to be addressed”. The company estimated that an additional 40 hours would be required to resolve all the problems. Au-Zone continued by saying: “Overall the ANT PC application [SensRcore development platform] was a much more pleasant experience. Once the network conﬁguration was understood, the developer was able to concentrate speciﬁcally on the application development and not worry about the underlying ANT protocol.” The power requirements for the modules were highly dependent on the system design, conﬁguration, and data transmit rates. However, the data demonstrated that the average power consumption for ANT was 115 µW compared with 9 mW for a successful combination – in use by many consumer electronics companies such as Garmin, Nike and Suunto – with lower power consumption and better performance than the IEEE802.15.4 radio plus proprietary protocol “hybrids” that are now ﬂooding the market. Independent engineering design services organization Au-Zone Technologies (www. au-zone.com) conducted a comparison test ZigBee – in excess of an order of magnitude difference – see Table 2.) In summary, Au-Zone said that ANT’s technology offered “signiﬁcant advantages over ZigBee for short range wireless sensor implementations requiring low power operation”. Speciﬁcally Au-Zone concluded: • The quality of the ANT module, ﬁrmware support, and documentation enabled the implementation of a more robust system with half the development effort. • The ANT module requires only 60 percent of the area of the ZigBee module with an equivalent antenna implementation. • The ANT module requires signiﬁcantly less power permitting higher data sensor rates using small coin cell batteries. By adhering to a strict standard, ZigBee operates satisfactorily in the deﬁned sectors for which it was conceived and designed. It meets that objective of interoperability. However, standards-based technologies are rarely the optimum engineering solution because they are subject to compromises. Chief among these are the attempts by the ratiﬁcation bodies to ensure the standards satisfy all interested parties (rather than meeting the speciﬁc needs of end applications). In the case of ZigBee the compromise manifests itself as additions to the protocol to cover rare implementations. The net result is delayed release, lower efﬁciency, increased power consumption and increased costs. ANT is a superior protocol to ZigBee for many ultra-low power practical wireless networking applications where interoperability is not essential. With the world becoming increasingly wireless – and design requirements for wireless links becoming more exacting – many designers may well look beyond the standard when specifying the WSN communications protocol in their next product or application. [1] “Wireless Security System Implementation Report” by Greg Lytle & Gerry Knopp, AuZone Technologies Inc. 20 Sep 2007. Figures 2(a), (b) and (c): Examples of practical point-topoint, star and tree WSNs. Table 1: A comparison of ANT and ZigBee. Microwave Engineering Europe ● March 2008 ● www.mwee.com 031_032-033_034_MWEE.indd 34 22/02/08 12:08:10 http://www.au-zone.com http://www.au-zone.com http://www.mwee.com

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Microwave Engineering Europe - March 2008 News Contents Comment Wireless Infrastructure: A Direct Conversion I/Q Demodulatordrives Favorable Basestation Cost-performance Metrics Wireless Infrastructure: Mobile World Set to Reshape the Internet RF Amplifiers: Latest Advances in RF Amplifiers Include a CMOS PA Operating at 77 GHz and Significant Advances in PAs for WiMAX and Broadband Applications Many Applications Still Require Unique Performance Benefits of BeO ACE Automated Circuit Extraction Returns to Real Design by Exploring Design Alternatives and Changes in Seconds Exceeding the Standard for Wireless Sensor Networks Products Calendar

Microwave Engineering Europe - March 2008

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