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Zigbee Wireless Networking - Deciding on ZigBee. Speaker: Li-Wen Chen Advisor: Quincy Wu 2009/11/17. Outline. Introduction 2.1 Deciding on the Right Technology 2.1.1 Wired Versus Wireless 2.1.2 Other Wireless Technologies 2.1.3 Other Software Protocols on 802.15.4 Radios
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Zigbee Wireless Networking- Deciding on ZigBee Speaker: Li-Wen Chen Advisor: Quincy Wu 2009/11/17
Outline • Introduction • 2.1 Deciding on the Right Technology • 2.1.1 Wired Versus Wireless • 2.1.2 Other Wireless Technologies • 2.1.3 Other Software Protocols on 802.15.4 Radios • 2.2 Deciding on a ZigBee Solution • 2.3 ZigBee Modules • 2.4 A ZigBee Checklist
Introduction • Zonal Intercommunication Global-standard, where Battery life was long, which was Economical to deploy, and which exhibited Efficient use of resources. • Reliable • Secure
2.1.1 Wired Versus Wireless • Wires need connectors. • Wireless has the interference problems. • ZigBee turns what is essentially unreliable into a very reliable network. • mesh networking • per-hop • end-to-end retries • acknowledgments • Wired solutions can be more expensive per foot.
2.1.2 Other Wireless Technologies • MAC and PHY ← 802.15.4 ← ZigBee • ZigBee is well-targeted at the wireless sensor and control network space. • 802.15.4 is not the only radio which targets this space. • ZigBee is not the only networking protocol which runs on the 802.15 MAC and PHY.
Non-ZigBee 802.15.4 radios • 2.4 GHz (ISM band), 250 kbps • The data rate is sufficient for the ZigBee protocol. • Products can interoperate worldwide in this RF space. • 900 MHz, 40 kbps • 868 MHz, 20 kbps
Wireless USB • generally focuses on the PC peripherals, but could be adapted to the sensor and control space • For example, Cypress CYWUSB6934 • Advantage • inexpensive • great on batteries • Disadvantage • is not meant to function on a scale as large as ZigBee can • doesn’t have the security • based on Ultra Wideband (UWB) • 480 Mbps data rate, two meters (about 6.6 feet) • lowered to 110 Mbps, up to 10 meters (or about 30 feet)
WiFi™ • also starting to see more use in sensor and control networks • a bit more expensive than ZigBee • typically requiring a larger CPU to run the full protocol • can mesh like ZigBee • but there are no interoperable standards for meshing WiFi • is not as good with batteries • using up batteries in hours, rather than the months to years of ZigBee, but not all control networks require batteries.
Bluetooth™ • used in headsets and cell phones everywhere • very secure • is relatively inexpensive • does not have the battery life of a ZigBee device • Think of Bluetooth battery life as days, not the months to years like ZigBee. • doesn’t scale well • is typically limited to networks of seven devices or less, whereas ZigBee networks can contain thousands of devices
Wibree • falls under the Bluetooth Special Interest Group • aimed at watches and body sensors • very, very low power • limited in the number of nodes in a network • At the time of this writing, Wibree was not in production, but still in the specification stage.
Z-Wave • aimed specifically at the home automation space • not a standard • Zensys is the only manufacturer of Z-Wave. • used by some of the large home automation manufacturers, including • Danfoss • Leviton • Universal Electronics • Zensys has formed a group called the Z-Wave Alliance, and regularly releases white papers promoting Z-Wave over ZigBee.
Proprietary radios • is still the norm today • used to be the case in operating systems, too • are the primary competitor of ZigBee today • The biggest issue with the proprietary radios is the lack of a protocol.
2.1.3 Other Software Protocols on 802.15.4 Radios • ZigBee is the primary networking protocol based on 802.15.4 radios, but many other protocols are also commercially available.
802.15.4 MAC • only point-to-point or a star network • doesn’t have • device • service discovery • interoperable applications like ZigBee • The MAC uses • the same per-hop retry mechanism that ZigBee uses • the same network associate commands • the same sleepy end-device polling commands • What the MAC-only solution is missing is • the application-level compatibility • the higher reliability • multi-hop nature of mesh networking.
SimpliciTI™ • Texas Instruments protocol • point-to-point • extremely small (4 K flash) • extremely simple • only 6 API calls
Synkro • originally by Freescale Semiconductor • point-to-point, not meshing • offers a form of frequency agility to avoid potential interference problems
MiWi • by MicroChip • peer-to-peer • mesh • specifically targeted at the Microchip MRF24J40 radio • has no cost associated with it if used with the MicroChip solutions
PopNet™ • by San Juan Software • a small-footprint full-mesh solution that could be considered “ZigBee Lite” • Like ZigBee, PopNet supports • broadcasting • unicasting • mesh route discovery • Unlike ZigBee, PopNet fits into 16 K of flash and does not require ZigBee certification.
TinyOS • a mesh networking technology written in a language called NesC. • This C-like language allows sensors to be treated as objects. • TinyOS was even adopted by one of the ZigBee stack vendors, MeshNetics, as the foundation for their ZigBee solution.
6LoWPAN • standardized by IETF.org • an 802.15.4 networking protocol that looks similar to IPv6 • Companies such as ArchRock are promoting this emerging standard for interfacing sensors to the World Wide Web.
2.2 Deciding on a ZigBee Solution • Carefully consider all aspects of your design when selecting hardware. • See http://www.zigbee.org for a complete list of ZigBee silicon and solution providers.
Is the ZigBee platform certified? • a platform called by the ZigBee Alliance • a combination of the radio • MCU • ZigBee stack software • The platform must be certified • if your product will interact with products from other companies. • A non-certified stack may not work with other ZigBee stacks.
Will the product use an integrated MCU/radio or a stand-alone radio? • an integrated MCU and radio • very cost-effective • allowing both • the ZigBee networking protocol • the application to reside in a single chip, 8-bit solution
The single chip solution contains everything required for the application except a power supply and sensors
a stand-alone 802.15.4 radio with some host CPU • the main question is whether ZigBee will need to run on that host processor • Most ZigBee implementations run really well on the integrated MCU/radiosolutions, but may not be portable enough to run on another MCU. • treat the ZigBee integrated chip as a communication “ module ”
the single chip solution • the ZigBee stack • a small serial “gateway” application • the host processor • the main application, • talking to ZigBee through a UART
Does the platform have enough memory for the application? • ZigBee is quite large. • When evaluating vendors • do a code-size estimate • build the Home Automation On/Off Light application for a ZigBee Router device. • check in the .map file • Feel free to call the vendor’s support line, or to check out their online help.
Does the price-point make sense for the product? • Consider the following production costs: • What external components are required? • Can the board layout be two-layer, or must it be four-layer? • What quantity will I ship? This can greatly affect price per unit. • Do the cost of the tools make a significant difference? • How solid is the software? Will it require significant development or debugging effort? • Create a bill-of-materials (BOM), and then price them out with one or more distributors. • Consider the cost of • manufacturing • the software
Is the part low-power enough for the power supply? • When evaluating low power for a particular radio or single-chip solution, consider both the • wake power • sleep power • If a node only wakes for a few milliseconds every few minutes, then power consumption while sleeping is everything.
Other questions when evaluating • What voltage range does the part support? • Does the part support all the required physical characteristics? • Are you familiar with the silicon vendor? • How good is the stack? • What tools are available to support compiling and debugging? • What reference designs are available? • What is the availability of the radio? • Is an alternate supplier a requirement?
2.3 ZigBee Modules • A ZigBee module is a board that is manufactured “application-ready.” • be government-certified • including CE Marking in Europe, IC in Canada, and FCC in the U.S. • have various I/O pins • binary GPIOs • analog-to-digital pins • be battery-operated • Modules save you money and time, and until your production reaches the millions of units, there is rarely a good reason to build your own board
2.4 A ZigBee Checklist • The list of things to remember when building a ZigBee application • Protocol Selection • Hardware Selection • Stack Selection • Application Development • Manufacturing • Deployment