Wi-Fi at 35,000′ – Nirvana or Not?

I’m traveling back from the IEEE802 plenary in Atlanta GA and have the opportunity to use the new inflight Wi-Fi service. I’d had a flight on the way out last week where I measured 0.4 sec latency and over 1Mbps throughput. While I’m still awed by the seemingly seamless connectivity that I have, I am wondering whether, especially for the business traveler, this new connectivity is good or bad.

What, You say? Isn’t connectivity a great thing? Everywhere? Well, perhaps. I can read the news, check my emails, win debates arguing bits of trivia with my fellow passengers, even update this blog. so maybe those are great things. But, if my boss comes to think that I’m online even when I’m in the air, I might get more chores and find that my few hours of airplane time are no longer optional down time %^). Thank goodness that Skype or other online VoIP programs are still frowned upon on-board, otherwise I might even have to be on conference calls!

However, YouTube works fine. Internet radio like Pandora, as well. That’s a nice feature. There’s great entertainment value to having the Internet at 10,000 meters altitude. I even checked out a webcam atop a mountain in the Sierra Nevada a little while ago. It’s amazing how well the Internet works in this otherwise rarified environment.

Battery life is suddenly more important. Having the Wi-Fi on means increased battery drain, and I don’t have the power adapter that lets me run from A/C seat power. As well, I’m not in the row that has that precious power connector. Maybe it’s time for one of those ultra-efficient smartbooks that so enthralls my blogging stablemate Glen Burchers (www.freescale.com/smartblog). Since they’re small as well, I’d have more room to juggle the can of soda and the ice-filled cup. That’s an idea.

How does this work? There’s some sort of  standard Wi-Fi g access point on board. Not sure if there’s a need for a distributed antenna, the fuselage should act like a waveguide. Doesn’t seem to have deep nulls when I move the computer back and forth, so there’s probably some antenna diversity as well. The access point gives up live Internet IPv4 addresses, in the 172.19.xxx.xxx range. Broadbandreports.com, however, indicates through their whois function a 12.130.xxx.xxx address, and no name. While I thought at first that the service might be satellite-based, it seems that it’s actually dozens of groundstations that provide a direct RF link to the aircraft, and from there to an internet gateway. There’s a generic map here. From that map, it looks like it’s only contiguous US coverage with a little bleedover at the borders.

On this trip it shows a 1265kbps download/266kbps upload, and now broadbandreports.com shows the user’s domain as att.net. A little faster than the last trip. Maybe it’s because we have a tailwind…

For all the entertainment and idle fun, the flight’s going to end soon, and I still haven’t logged on to my work email. Is this nirvana or what? I guess I’ll have to find out later when my boss asks me why I didn’t read his emails to me…

IEEE 802.15.4g – Big Progress May Be Happening

The path to standards is rarely an easy one, especially when there are a number of encumbent systems that all want to protect their interests and ensure that somehow their currently deployed systems are not rendered completely obsolete by the establishment of a new standard. This week, with many uncertain of forward, positive movement, it looks like there might be a consolidation taking place that could bring this standard to fruition on the agressive schedule they have advertised.

At this plenary session of the IEEE 802, here in Atlanta, Georgia, the 15.4g group has demonstrated a whole lot of cooperation in presenting what looks like a reasonable approach to a smart utility network wireless standard.  The first real forward movement was when the different, competitive FSK proponents came to the mike Wednesday with a proposal that established a common mandatory mode that all FSK radios could support. It wasn’t exactly one major competitor’s current system, but neither was it the other major competitor. So there’s pain/opportunity for all. This proposal may have tickled the different DSSS proposers enough that they, too, were able to consolidate their differing positions and propose a common approach. The OFDM’ers had long ago streamlined their proposals.

The new document, IEEE 15-09-0787-02, establishes a default, minimum interoperability that allows any device some level of communications with another: 50kbps, two-tone FSK. From there, a device that joins a network has the potential to step up to much higher FSK rates and more complex modulation schemes, or go completely to OFDM or DSSS and run at data rates approaching 1Mbps. It’s somewhat like the world of IEEE802.11, where devices are supposed to have support for the basic DSSS mode, 802.11b, but 99% almost immediately move to 802.11g or 802.11n speeds and modulation constellations. In fact, in some cases, the savvy access point owner has already gone in and reconfigured their AP does not support 802.11b modes and rates at all, so that the network never needs to operate at the slowest rate. Instead, the new device that joins the network selects the OFDM modes and never looks back.

For the smart grid, the concept is that the network administrator (in this case, the utility or the company managing the network for the utility), will determine what the supported modes might be for their network, and all devices that they intend to work within that network will be preconfigured to support the network parameters. The default 50kbps FSK mode would be technically available for use in the new device, but the network operator might not use it. This can work for the smart grid since most networks are private and there’s no intention for third-part, unrelated devices to be able to join that network, so no reason for that network to have the “backwards” interoperability specified by the spec.

OFDM seems to be the big favorite for where many utility networks will operate – excellent multipath/fading characteristics, robust modulation, lots of flexibility in data rate, coding, modulation constellations, and symbol size, make it fine for communicating in urban, suburban and rural environments. FSK might still find a home for gas and water meters, where very low power consumption is important since it’s running on a battery intended to survive for 15 to 20 years.  DSSS is a little more difficult to predict – will it find a home in the smart grid?

The IEEE802.15.4g group will now spend the next 2 months establishing a baseline document that reflects the efforts of all the proponents. That document will be ready for the Los Angeles meeting in January 2010, where it will be voted on and (hopefully) approved as the draft. Once that occurs, the editing can focus on resolving remaining technical and editorial issues, and perhaps move towards an ultimate adoption at the end of 2010 or the beginning of 2011 as the specification for the wireless side of the Smart Utility Network of 2012 and beyond.

American Telemedicine Association inks an agreement with ZigBee

Exciting news for the advancement of telemedicine and telehealth services and systems – this morning the ZigBee Alliance and the American Telemedicine Association (ATA) agreed to establish a liaison relationship that allows focus on the abilities of ZigBee Health Care, an open standard, to bring secure wireless monitoring and management to noncritical, low-acuity health care and wellness services.

What does this mean for the average person? The ATA, founded in 1993, is the leading organization within the US advocating for the promotion and use of telemedicine and telehealth services to improve the lives of everyone. Their membership is broad and influential, supported by many companies, non-profit organizations, and medical professionals, with links to other nations’ similar organizations. They have multiple, clear goals – the first and foremost to educate government and the public about the values of using telecommunications technology to improve the delivery of health care. They have led the way to establish practice guidelines and standards on how to deliver quality remote health care services. And relevant to the announcement, they foster networking and collaboration between interests in medicine and technology.

ZigBee Health Care has quickly risen to begin to fill the needs of the telehealth and wellness communities. There are already ZigBee-enabled systems in place in group care facilities and hospitals. The Continua Health Alliance, with its worldwide reach and focus on developing a system of interoperable personal health solutions that extends into the home, had announced in June 2009 their adoption of ZigBee for their next generation wireless connectivity.

ZigBee Health Care natively supports IEEE11073-enabled health care devices like glucose meters, weigh scales, blood pressure monitors, medication monitors, etc. It provides fast, efficient, battery-conserving two-way, mesh networked, flexible and robust wireless communications targeted for use in homes, fitness centers, retirement communities, nursing homes and a variety of professional medical care facilities.

The collaboration that this liaison relationship has established will help to emphasize the benefits telecommunication technology provides in improving the quality and efficiency of medical care to patients. But telemedicine is just one side of the care coin – the other is health and wellness monitoring, which is important as well. This means, certainly for those aging independently, or those with mobility challenges, that non-invasive monitoring of their environment and their activity is an extremely valuable adjunct to telemedical monitoring. Knowing that a loved one is ambulatory, that they are attending to their needs, that the thermostat is set properly and that the house is secure, are all environmental aspects important to overall health and wellness, and can have an impact on the care provider’s decisions.

Today’s announcement by the ATA and ZigBee about the establishment of a new liaison relationship signals a new level of commitment by industry leaders to drive the value and functionality of telemedicine and telehealth, to educate health care professionals and consumers, and to improve the quality and efficiency of health care.

IEEE802.15.4 SUN – It’s already an interesting week

Just a few days ago, the IEEE802.15.4g task group got to see a single draft document that represents the compilation of the major PHY proposals. The editors did a great job in merging together some significantly different proposals. But, even this afternoon, the validity and purpose of this merged document was contested, with at least one person who was calling it the baseline and others who believed it was strictly a “similarities and differences” document, like its name implies.

Today, there were nearly a hundred people in a room built for 50, and the temperature was rising as were the emotions. Tomorrow there may be even more people who weren’t able to get here today. The draft compilation presents multiple versions of FSK modulation, at a variety of data rates, bandwidths, numbers of tones, and BT products. It also discusses the use of OFDM with a number of subcarriers, at a large variety of channel bandwidths, and an equally large number of data rates. There’s even some DSSS in there, with a variety of spreading ratios and codes to accommodate data rate in given bandwidths. Add to all this, suggestions for data whitening, differing CRCs, FECs, and a vast number of licensed and license-free frequency bands, each with a proposed modulation type. Oh, I almost forgot, there’s Frequency Hopping spread spectrum as well. So, for modulation types, count the various m-ary FSK, BPSK, MSK and O-QPSK, and QAM, with varieties of shaping. For spreading modes, there’s OFDM, FHSS, and DSSS. There’s also the non-spreaded, single-carrier stuff.

In the US, these proposals might allow the use of the eventual radio technology under FCC part 24, 15, and 90 rules. There are specific band segments from about 300MHz to 2500MHz called out for different regulatory regions. Channel bandwidths go from 12.5kHz to over 400kHz. Wow, I didn’t even know there was a number of frequencies in the 1605 to 1625 MHz band that could be used for Smart Grid stuff.

Working for a telecom systems semiconductor manufacturer, I can see how all this can be implemented in a fairly compact communications processing engine, and one that could be very efficient in code space, power consumption, and overall complexity. But having a plethora of modes, operating states, modulations, etc., means some real challenges in testing and validation, which can adversely impact interoperability and drive cost. And the system analog linearity required because of the potential for OFDM can mean increases in power consumption and cost for the RF front end components.

While the editors did a fine job of pushing together into a single document all the different proposals, it seems a long way away from being a document upon which this group can agree by the end of the week. It’s only Monday evening, and we have almost three days remaining of sessions. Maybe there’s a chance that consensus will occur – but the jury is skeptical.

IEEE 802.15.4g Smart Utility Network – Will it be cast this week?

Arrived here in Atlanta just a few hours ago, and am looking forward to about 30 hours of consideration and debate on what the Smart Utility Network of 2012+ could look like.

Of course, FSK is critical to make sure that legacy devices and networks can play. Count on OFDM being a strong part of what will be, especially because it provides strong performance at higher data rates in extreme multipath environments (and anyone who’s seen a water meter installed 3m below grade knows how hard it is to get wireless to that). Extra bandwidth provides added resiliency and the ability to support new, value-added services.

More later as the week goes on.

ZigBee Health Care – The Real Story

Earlier this week we debuted the first-ever public ZigBee Health Care webinar, which dove into the huge opportunity for telehealth and telemedicine applications and the tremendous need for short-range wireless. ZigBee provides robust and reliable, battery-efficient wireless communications throughout the home, group care facility, or professional care environment and has quickly become an important part of the telehealth/telemedicine picture.

Here’s the link to the recorded event: ZigBee Health Care Webinar

ZigBee wireless technology has already found its way into the home. The Smart Grid has adopted ZigBee as one of the primary methods for communications from the electricity meter to devices inside the home. These include simple things like “refrigerator-magnet” energy displays to more sophisticated systems that provide the consumer a powerful way to manage energy costs and can even allow, with the consumer’s permission, peak-shaving through shutting down briefly high-power-consuming devices. ZigBee RF4CE is rolling into the home via the remote control, TV set, Blu-Ray player, and set-top box, solving the needs of the market and making the universal remote a reality. Major CE manufacturers have product in stores today, with many more SKUs scheduled for 2010. ZigBee is on its way to becoming ubiquitous in the home.

The health care space is big. People spend the majority of their time in and around the home. ZigBee’s growing presence there makes it an excellent way to bring telehealth connectivity to small devices in that environment. That’s part of the reason that the Continua Health Alliance adopted ZigBee technology earlier this year for residential, group and professional environments.

Nearly a thousand people registered to participate in the live webinar, which features insights from industry and thought leaders like Philips, AT&T, Awarepoint and RF Technologies.  The event was recorded so that even if you weren’t able to tune in for the live event, you can watch it at your leisure.  Watch the webinar – then get involved!

RF4CE and ZigBee: Two Complementary Faces of IEEE 802.15.4

ZigBee wireless technology has been around since the first public release in December 2004. Based upon the extremely flexible and robust IEEE 802.15.4 short-range wireless protocol, the ZigBee Alliance currently numbers over 300 member companies. RF4CE got its start back in 2006 when Sony came to Freescale with a need to replace the increasingly unreliable infrared (IR) remote control technology with something that could work from anywhere in the home. Starting with IEEE 802.15.4 as the foundation, ECNet was born, then enhanced as SynkroRF, and ultimately became the foundation of RF4CE, which, because of its underpinnings of IEEE802.15.4 and its value in the residential/consumer space, was brought into the ZigBee Alliance fold earlier this year. While both ZigBee and RF4CE are related by heritage, marriage and mutual interest, they address very different market spaces.

ZigBee is a very rich and powerful set of wireless tools. Recently adopted as one of the short-range radio communications cornerstones for the US Smart Grid (http://bit.ly/3YDYi4) as well as smart grid efforts throughout the world, ZigBee wireless networking technology grows mesh networks that have high reliability even with interference, physical obstacle, and changing environment. ZigBee was adopted earlier this year by the Continua Health Alliance (http://bit.ly/XpkcB) to address some very real connectivity challenges in residential, group care and professional environments, not adequately addressed by their first-generation connectivity choices: Bluetooth or USB.  ZigBee wireless is finding its way into retail, telecom, building automation, home control and monitoring.  While it’s the 15.4 radio that provides much of the basic performance that makes ZigBee work, it’s ZigBee’s extremely flexible networking, well vetted security at link, network and application levels, a certification program that ensures broad interoperability, and very much so, those 300+ companies, many of whom are leaders in their industry segments, that make ZigBee so compelling.

RF4CE brings a rich and powerful set of wireless tools to the extremely cost-sensitive and complexity-adverse consumer electronics (CE) environment. The infrared (IR) remote control has run its course – it is rapidly losing the ability to provide basic required functionality. As well, the requirements for whole-home coverage, for incredible robustness no matter the environment, have made RF4CE the right way for the CE industry. The fact that industry leaders and fierce competitors like Panasonic, Philips, Samsung and Sony (http://bit.ly/175bW7) assembled their hundreds of years of  experience to vet and adopt RF4CE speaks to the strength of the solution and the importance to the market. Consumers already have begun to see the value of RF4CE to make their experience more fluid. But for all its similarities, RF4CE in many ways is a very different animal than ZigBee.

RF4CE and ZigBee are both firmly based on the internationally approved open standard IEEE 802.15.4. Transceivers are manufactured by many of the world’s largest semis as well as others. RF4CE concentrates on the environment in and around CE equipment. For the typical consumer, the remote is the command center of their multimedia experience. In RF4CE lingo, the remote control is the “controller”, while TVs, set-top boxes, multimedia players, etc., are all “targets”. Most of the time, since remote control technology was created, it’s the remote control talking to the TV, not the other way around. But that doesn’t need to be the only paradigm anymore.

While the usual model was the remote talking to the TV or Blu-Ray player, most people had more than on target device. Some of those people were bold enough to want to control all the devices from one controller. The many-in-one, zillion-button remote controls, which required a PhD and the ability to memorize unusual sequences of button pushes, were the only way to get CE devices to at least appear to play together. And while many of those were sold, few of them ever delivered on the vision. But, in the RF4CE world, one controller can introduce itself to a target device and query that device for its feature set. That’s a whole lot better than having to push the ON/OFF button 300-400 times in one of those old learning multifunction remotes! As well, once a controller has been introduced, it can then share that information with other targets in the same family, so that the TV set knows about the Blu-Ray player, and about the set-top box in the other room. Once device functionality and connectivity has been shared, the consumer can truly move to the scenario where inserting a disk into the Blu-Ray player can cause the TV to switch to the HDMI input connected to the player, turn on the high-def audio amps, and dim the lights. The two-way capabilities and RF wireless range performance of RF4CE makes this practical.

RF4CE deals with interferers extremely well. The 2.4GHz band is license-free worldwide, so a CE OEM doesn’t need to worry about different radio frequencies for different geographic regions. Regulatory compliance is much more straightforward. In theory, one device can ship to all regions. But using the 2.4 GHz band means dealing with Wi-Fi, microwave ovens, Bluetooth, older cordless phones, etc. The “big dog” interferer in the 2.4 GHz band is Wi-Fi, and 99+% of all Wi-Fi usage is on channels 1 (2412 MHz), 6 (2437 MHz), and 11 (2462 MHz). Since the Wi-Fi signal is 20 MHz wide, this means that there’s a 5 MHz gap between each of those three canonical channels, and those gaps correspond to IEEE802.15.4 channels 15 (2425 MHz) and 20 (2450 MHz). In addition, the 15.4 channel immediately above Wi-Fi 11, channel 25 (2475 MHz), is clear as well. So RF4CE exists completely on 15.4 channels 15, 20 and 25.

RF4CE controller devices set up relationships with target devices, and the target device decides on what the best of those three channels are for their local environment. The controller device records that in its memory, so that if it needs to talk to the TV in the family room, for instance, that TV is listening on channel 25. However, the set-top box in the utility closet might be listening on channel 15. All this info is kept by the remote control. If a new interference source occurs near one of the target devices, it is free to move to either of the other two channels. The remote control has embedded intelligence that allows it to find its intended target even if the target has changed channels from the last time they communicated. And RF4CE does this because it uses a very cost-effective, strict star network architecture, with no meshing.

ZigBee is a little different. Instead of occupying 3 frequencies with ad-hoc channel agility, it prefers to stay put on a single channel. And it relies very much on meshing to manage overall network connectivity. It’s free to pick up the network and move it to another channel, but it does that only when interference becomes a significant issue. But it’s the same 16 IEEE802.15.4 channels.  ZigBee systems can be very large – some of the biggest deployments number many thousands of devices in a single building, so moving the entire network is often difficult, but changing the routing from one device to another is easy and happens on the fly. This way,  devices that suddenly undergo local degradation of a specific path to another node can immediately shift to a different neighbor and get the message through. This meshing, while incredibly useful in rich network environments, isn’t necessary to meet the overall CE market needs that RF4CE addresses.

One of the biggest challenges to any technology that needs broad interoperability is ensuring just that. Interoperability comes only through carefully defined functionality and rigorous testing. Both RF4CE and ZigBee are widely deployed technologies from **many** different vendors – that means that an OEM has a huge selection of silicon vendors, stacks, middleware developers, etc., from which to choose. It means that there’s tremendous competition to drive prices down and features up, and allow advancements and feature enhancements to occur with regularity. This is all great for the OEM and developer. Both technologies are based upon IEEE802.15.4, so that commonality means that a lot of the heavy lifting, ensuring that the RF/PHY and MAC from one vendor is interoperable with another, has been done. And since both are part of the ZigBee Alliance, both technologies take advantage of an interoperability and certification program that has established clear guidelines and firmly defined testing procedures. There are a multiplicity of internationally recognized test houses that compete to provide these services, combined with regular interop events where similar products from different manufacturers can demonstrate interoperability and conformance to the spec.

RF4CE and ZigBee,  under the skin, share much of the same technology. How that technology gets used for RF4CE is well optimized for the Consumer Electronics space; likewise, for ZigBee, while the settings are a little different, the technology is situated optimally for residential, commercial and industrial applications. RF4CE and ZigBee are both based on the robust and flexible IEEE 802.15.4 wireless standard, each takes advantage of that standard in ways to align it best to their own market needs.

Wi-Fi Direct – One Step Back, Many Steps Forward

Way back in the last century, a plucky band of engineers and visionaries got together under the aegis of a group called IEEE 802.11 to craft a technique to allow computers to share information via wireless networking. At the time, Ethernet was finally becoming established as the network connectivity medium, but already there were those who railed at the thought that the digital communications link came at the cost of a copper tether.

By 1997, the group had been able to ratify the very first version of what is now a 500-million-unit-per-year wireless technology. The initial version of IEEE802.11 was designed to accommodate two different network topologies. The one we all know and use is Infrastructure mode, where wireless clients like your netbook or PC communicate to an infrastructure access point device that is connected to the Internet in some fashion. The other one was Ad-Hoc mode, which allowed two or more client devices to establish their own peer-to-peer network.

Infrastructure mode probably accounts for 99+++% of all current Wi-Fi usage. Most people quickly got used to being connected to the Internet and using their email clients and web browsers to send and receive files, even to the next cube in the office. And for most traditional environments and uses, that was fine. Ad-Hoc is almost never used because Infrastructure mode was sufficient then for most people. As well, since Ad-Hoc mode was not commonly used, there wasn’t a guarantee that either client device was going to interoperate well using the mode.

My own experience with Ad Hoc was back when IEEE802.11b devices were finally getting cost-effective, around 2001. A number of us bought a handful of the original Lucent Orinoco Gold cards, put them in our Thinkpads, and spent an hour or two figuring out how to take advantage of the wireless link. It wasn’t easy, but then again, even Infrastructure mode was chancy back in the early days, before the Wi-Fi Alliance got the bugs worked out of the interoperability program. It was more of an experimentalist experience than it was a transition to a new level of business productivity. Once we’d finished our exercise, we pretty quickly went back to the Ethernet cable and its reliable yet tethered connection.

Until now. Files have gotten pretty big. Multimedia and office stuff like Powerpoint can regularly choke email servers, and unnecessarily tax infrastructure resources. Why send that file via the email server which might be 1000 miles away when the recipient is just 10 feet away? And when someone’s out and about, away from their usual Wi-Fi network, but near someone else with whom they want to communicate or share, having to use the 3G network or find a hotspot just doesn’t make sense when there’s the big gun of Wi-Fi under the hood.

The Wi-Fi Alliance, through their Wi-Fi Direct announcement, has re-established a feature that was always there but in the past wasn’t really promoted nor generally known. Since Wi-Fi is so ubiquitous, formalizing the feature makes perfect sense.  With native Wi-Fi speeds up to and beyond 100Mbps, the direct connection can make file transfer between two co-located machines blazing fast.

So, in a return to a feature long ignored yet with high potential, the formalization of Wi-Fi Direct means that we can now start taking full advantage of the native connectivity that our Wi-Fi chips have. Let the connectivity begin!

Energy Harvesting a Natural for ZigBee

Everyone talks about the machine-to-machine (M2M) universe where the information from a plethora of cost-effective sensors allows people and systems to make even better decisions. One of the many challenges has always been the connectivity required for these sensors.

Let’s put this in perspective by looking at it from the point of view of one of the places you know best – your home. In the home, one is generally concerned with safety, security, functionality and convenience. Window-break/latch open sensors on each exterior window and exterior door lock/ajar sensors might be a very handy thing to have to ensure that the windows and doors are secure. And knowing that the door or window is shut is a very different thing from knowing that the latch is engaged as well. If the home uses some form of gas for heating, cooling, laundry or cooking, there’s another opportunity to make sure that gas isn’t leaking into the house from one of the obvious spots. In the HVAC system, heat flow, pressure sensors and information from those exterior window/door sensors could improve knowledge of where the warm or cold air is going, and air dampers and register controls could mitigate problems or save energy costs by spending less money controlling climate in lightly used areas. There’s lots of other applications for low-cost simple sensors in the home, but that’s not the point of this discussion.

Essentially, all sensors need power to run, and to transmit their information to Someone Who Cares (SWC). It can be difficult enough to design a power-efficient sensor that can measure motion/occupancy or a security perimeter. But, it’s often even harder to get that information delivered from the sensor to the security system without resorting to wires. Wires mean that the security system can push power out to the sensor device – but without wireless, the sensor device needs to either last for a long time on a battery or scavenge energy from its environment. And, if the wireless technology used to transfer the info back to SWC is a power hog, then scavenging is often unfeasible and the battery doesn’t last long.

ZigBee wireless technology is based upon the low-energy IEEE802.15.4 international wireless standard. The protocol is simple and efficient. The messages are brief and concise. For something as simple as an exterior window security sensor, the transmission might be nothing more than the fact that the window is still closed and secure, which it sends every 5 minutes to remind SWC that the sensor is still there and still vigilant. For ZigBee, moving that information from the sensor to the network and getting an acknowledgement that the message was received takes about two thousandths of a second. That’s about 500 transactions per second! In terms of the amount of energy it takes to make that transmission and acknowledgment, it’s an order of magnitude less than the kinetic energy of the eponymous honeybee buzzing around the garden – more like a that of a housefly. ZigBee is really fly-power… In engineering terms, it takes about 50-70 microjoules for that transaction, and in theory a small, 100mAh button battery has enough energy for well over 10 million transactions (exclusive of power requirements for the sensor itself or of silicon quiescent current). And even with that small amount of energy consumption, the range is between 20 and 70 m indoors and hundreds of meters outside.

The fact that the sensor is attached to the window means there are potentially multiple sources of scavengeable energy available, all very practical for that fly-power ZigBee radio. The first? Light. The same light-collecting photo cell that’s in those giveaway “solar-powered” calculators generates plenty of energy to run that ZigBee radio. That “solar” cell generates plenty of energy for this ZigBee radio, even in a dimly lit room. And the excess energy for when there’s no available light? Can be stored in a super/ultra cap that’s part of the circuit. Or, instead of light, there are inexpensive materials that derive usable energy from a small temperature difference. If that sensor is detecting glass breakage, it might be stuck on the glass. On one side of the window, there’s the uncontrolled climate of the great big world – on the other, it’s the well controlled climate of the inside of the home. Using one of these thermoelectric generators no more than the size of a US ten-cent piece, a 10F temperature differential from one side to the other again supplies more energy than that ZigBee node needs to meet the task. Vibration, in the right scenarios, is another way to get power out of the environment. The list goes on and on for easily scavenged energy sources that are sufficient to run that ZigBee radio. And even if the sensor needs to run on a coin-cell battery, say a CR2025 or so, the battery’s shelf life may have passed and the battery might be leaking long before the available energy had been depleted.

There’s some other short-range wireless technologies out there claiming some special position as the “energy-scavenging” champion, or even more egregious, that they hold some arcane knowledge on scavenging energy. When comparing apples to apples, one discovers that these are all proprietary, single-sourced, and in fact no more energy efficient than IEEE802.15.4. International standard? No. Useable license-free anywhere in the world? Nope. Supported by the majority of tier 1 semiconductor companies and a host of smaller players? Not that either. Vetted by years and tens of millions of units in the market, with dozens of Fortune 500 companies (over 300 companies total) standing behind the technology? Sorry, no. And the list goes on.

Freescale knows a thing or two or three about energy management, learned from decades in the automotive and two-way/cellular radio silicon businesses. Whether it’s power management to manage the battery life of that cell phone as best as possible, or to do embedded processing for the automobile parked in the long-term lot at the airport without running down the battery, or to squeeze usable energy from a sliver of a solar cell to charge a battery, Freescale’s been managing electrons for a long time.

ZigBee’s RF4CE technology has already been adopted by the Consumer Electronics industry as the green, energy-efficient RF wireless communications replacement for the legacy IR remote controls. Battery life has gone up manifold. Means a lot to the CE companies, since they’d like to do their part to reduce energy consumption and the amount of batteries headed to the waste dump.  Freescale is a big part of the development of RF4CE, including its industry-leading power-saving modes. ZigBee Batteryless is the up-and-coming building control technology that manages on the energy generated by the user’s toggle throw or button push. The Smart Grid has embraced ZigBee wireless as part of its effort to better manage energy consumption and contain cost.

ZigBee wireless technology is already extremely energy efficient, in energy-scavenging, battery-operated, and yes, even mains-powered uses. It’s flexible, with robust and reliable communications, usable anywhere in the world, available from many, many manufacturers, and simple and straightforward to deploy. Scavenged energy is a natural for ZigBee.

ZigBee’s Value to Personal Health Care

Aging independence, management of chronic disease, and improving general health and wellness: Three really laudable goals of the health care industry, and most practical if health care can be reshaped to fit people’s lives, not the other way around. Since people spend the most time in and around their home, the home must be the target for any successful strategy in telehealth. And that means short-range wireless – here’s why.

The average consumer, who might be a senior living in their own home, someone with diabetes who needs to keep tabs on their A1C, or the “worried well” fighting hard to maintain their good health, probably already has the ubiquitous weigh scale in their bathroom. We all know the routine: step on the scale,  take a weight measurement, grumble that it’s more (or rarely, less) that expected. Then what? Ideally, that reading gets added to a personal database that allows the consumer to track their weight, compare that and their general health and situation to others, and really begin to understand what they need to do to stay healthy. But for 99.99% of us, it never gets that far.

As the consumer brings home more and more personal health care devices, some prescribed by the physician, others purchased at retail, the need to record information and then take action on that data becomes all the more important. And aggregating and moving the data from the sensing devices to the analysis tool, whether that’s the consumer’s netbook, the Personal Health Record (PHR) or the physician, means that all these devices strewn over the home need to be able to communicate. It’s one thing to run cat-5 networking cable everywhere, very expensive and not very tidy. Using wireless seems to fit, but having a cell phone modem in the weigh scale isn’t cost effective. Using Wi-Fi (assuming the home has a Wi-Fi access point) only works if the weigh scale is connected to a wall outlet to keep the batteries charged up. Same holds true with the cellular-connected weigh scale, to be sure.

So, it can’t be any wireless, but needs to be capable of covering the whole home, very low-energy consumption so that running on a coin cell or a couple of AAA batteries gives a year or more of lifetime. There’s Bluetooth, but Bluetooth’s short radio link range (10m with the wind blowing in the right direction, 3-5m in most real-world environments) means that the weigh scale, glucose meter, blood pressure monitor, pulse-ox, and medication monitor all need to be in the same room as the aggregating device. And then there’s the power consumption requirements for Bluetooth – remember the Bluetooth computer mice that have a docking station to keep the batteries charged. That won’t work for the weigh scale!

A few months ago, back in June 2009, the Continua Health Alliance, with the mission to improve personal telehealth for all, announced the selection of ZigBee wireless technology as the next-generation ultra-low-energy wireless to link together all those health care devices in the home. ZigBee’s native range of 20-70m in most indoor environments meant that each device in the home had the ability to communicate directly to the aggregation point. Now, the individual health care devices can stay where the consumer prefers, and all these devices can communicate back to that central aggregator, whether that’s a netbook, a set top box, cable modem, or 3G gateway connected to the internet. ZigBee sips energy, allowing a simple application like a weigh scale to outlast potentially the shelf life of the batteries installed.

The ZigBee ecosystem includes technologies like RF4CE, the technology that is now replacing the legacy IR remote control communications link. With that link, ZigBee-enabled health care devices could have their data routed to display on the home big-screen, instead of the consumer having to boot up the home PC just to have a look at their fitness data for the past month. How’s that work? There’s a number of major internet/media service providers that have either announced the use of ZigBee or will be soon. Initially, their interest comes from at least two different directions: one is to use RF4CE to allow the set top box to be buried in the utility closet yet controlled from anywhere in the home; the second is to offer into the home health care monitoring services that might be requested by the care provider, relatives and loved ones, or the consumer. Once you have one, the other becomes pretty straightforward.

ZigBee wireless is already moving into the home via the Smart Grid effort – in the United States, the National Institute of Standards and Technology has already put ZigBee on the list of the allowed connectivities to enable the US Smart Grid. For the home, this means that the electricity meter may use ZigBee to show current energy pricing on a little refrigerator magnet display, on the Energy Detective using Google Powermeter (http://bit.ly/4sqcIt), or on the TV set on the always entertaining “home utility network” channel. With energy costs skyrocketing, the consumer is looking for more and more ways to control costs, and keeping the thermostat in check and the number of unneeded lights to a minimum is a real challenge. ZigBee Home Automation has already been adopted by many products in the residential space and can give the consumer real visibility into just how much energy that TV set left on in the kid’s room uses.

Freescale knows a bit about the medical/health care device space. Our sensors, processors, and industry-leading IEEE 802.15.4 wireless enable applications as broad-reaching and diverse as multi-million dollar diagnostic medical imaging systems to wearable ECGs to pocketable glucose monitors. You can always read more at www.freescale.com/medical.

ZigBee wireless technology is based upon the worldwide IEEE 802.15.4 standard. This international standard fits the bill for major governments, regulatory domains, and energy providers. For the user, a true standard means one that has real interoperability, and in the case of 802.15.4, availability from most of the world’s top silicon vendors, and many more smaller semis generating strong price competition. It’s become a part of critical industrial control, of hospital and care-facility patient elopement systems, of factory automation processes.

Continua’s June decision was the beginning – the further collaboration announced by both Continua and ZigBee just a couple weeks ago was the next step in making it straightforward for the consumer to bring health care devices and services into their home, and fit them into their life, rather than having to modify their lives to fit the technology. The native robustness and connectivity that ZigBee wireless technology brings adds huge value to the promise of personal health care. How will you use ZigBee in your consumer health care application?