Wireless Systems Design

What’s Happening In Short-Range Wireless?

There are literally dozens of methods used in transmitting data wirelessly over short distances. Most of these technologies are official standards and each has carved out a niche in the wireless world. Some of the standards are flexible across a wide range of applications while others are optimized for a specific use. In any case, all these wireless technologies are regularly being updated and improved. Here is a look at what is happening with some of the more commonly used standards like Wi-Fi, Bluetooth, UWB and ZigBee.

Wi-Fi
The IEEE 802.11 wireless standard has grown from its initial 1997 introduction into a major industry and is one of the most highly developed wireless standards in the world. Most of you have come to rely on Wi-Fi connectivity as much as your cell phone. You expect to get a Wi-Fi connection to your notebook wherever you are whether it is at an airport, hotel, public hot spot, access point within your workplace, and by way of your home’s wireless LAN. Wi-Fi has reached a ubiquitous stage and more is on the way.

Karen Hanley of the Wi-Fi Alliance indicated that as of mid-November over 4000 products had received the Wi-Fi Alliance certification of "guaranteed" compatibility and interoperability. One current area of certification activity is with the 802.11n standard. The Wi-Fi Alliance is certifying draft 2.0 products before the final 802.11n standard has been ratified by the IEEE. Over 140 draft 2.0 11n products have already been blessed meaning that the draft 2.0 is pretty much the final version. Final ratification is expected in July 2008. Nevertheless, users are already enjoying the 100 Mb/s+ performance promised by this standard. And speaking of higher speeds, the IEEE 802.11 VHT Study Group is already at work examining standards for potentially higher data rates to 1 Gb/s.

Other developments in Wi-Fi include a decelerated roll out of municipal Wi-Fi networks in cities around the country. Hundreds of cities already have broad Wi-Fi coverage for citizens, but other cities are backing out of the muni trend as they discover the high operational and maintenance costs.

Another major development in Wi-Fi is the rapid incorporation of Voice over Wi-Fi or Voice over Wireless LAN. Well over one-hundred cell-phone models now incorporate Wi-Fi, meaning that it can provide Internet connectivity or VoWI-Fi phone calls. The Apple iPhone and RIM BlackBerry both incorporate Wi-Fi but not VoWi-Fi, while others include Wi-Fi as an alternative for voice when cellular coverage is poor. These dual-mode phones that handoff between cellular basestations and Wi-Fi access-points are becoming popular in the enterprise as companies look for economies in telecommunications. This is all part of the fixed mobile convergence (FMC) movement in which a single phone can become the employee's only phone where he or she uses the cellular mode off campus but use the WLAN network to make calls at the office. Cellular provider T-Mobile now offers dual-mode phones and a service called [email protected] that permits Wi-Fi phone calls Dual mode phones are expected to continue to grow in popularity as the consumer expects communications alternatives in different environments.

In other Wi-Fi developments, new chipsets with very low power consumption are becoming available, making them suitable for dual-mode phone service as well as some low power applications in industry previously denied to Wi-Fi because of their inherent power hungry characteristics. Low power 802.11b/g chips are now suitable for some wireless sensor networks and other industrial monitoring and control applications.

The IEEE continues to develop new and related 802.11 standards. Amongst some of the more notable are 802.11p which is designed to provide Wi-Fi usage in the 5.8-GHz range between vehicles and roadside services at speeds to 200 km/s at up to 1000 feet. The 802.11s standard provides for mesh Wi-Fi networks. The 802.11y standard implements Wi-Fi-like operation in the newly available 3650-3700 MHz band.

Wi-Fi is a robust and reliable wireless data protocol and it is getting better and more widely used. Look for its continued growth as it becomes more viable in other wireless applications and as its performance continues to grow. More and more Wi-Fi is being built into products like HDTV sets, digital cameras, printers, and camcorders. JetBlue is testing Wi-Fi access on it flights to provide e-mail access. Overall, Wi-Fi continues to be a solid bet for new wireless designs.

Bluetooth
Bluetooth continues to be the overall wireless standards leader with over one billion Bluetooth enabled devices shipped to date, according to Mike Foley, executive director of the Bluetooth SIG, the keeper of the standard. About half of those are Bluetooth headsets for cell phones. Bluetooth continues to move forward most recently with the acquisition of Nokia's WiBree standard technology. Now called Ultra-low power Bluetooth, this latest version will bring Bluetooth connectivity to a whole new range of products previously shut out of the wireless movement because of power issues. ULP Bluetooth is now being incorporated into battery-powered sports/fitness and medical devices worn by individuals. It can power wristwatch devices and other products in the home and auto with very low power requirements.

Bluetooth has yet to roll out products based on its ultra wideband (UWB) technology, but look for that in the near future as the need for video connectivity increases. This quicker version of Bluetooth uses the WiMedia standard of OFDM to produce speeds up to 480 Mb/s over a range of a few meters. It uses the spectrum between 3.1 and 4.9 GHz so a high-speed Bluetooth radio will contain the usual 2.4-GHz transceiver with a net data rate of 2 Mb/s as well as a higher-speed UWB transceiver that is expected to deliver a net data rate of 200 to 250 Mb/s.

Ultra Wideband
Speaking of UWB, the development phase is over and vendors are now selling UWB-enabled laptops and peripherals that implement the wireless USB standard. Any device with a USB port can be made wireless with a UWB dongle and matching port for short range but very high speed wireless transfers. UWB is also being built into some laptops as well as consumer devices like digital cameras to speed the transfer of high res photos to the PC or printer. Meanwhile, UWB vendors are working on new chipsets for the upper UWB bands from 5 to 10.6 GHz.

ZigBee
Based on the IEEE 802.15.4 standard, ZigBee provides short range wireless connectivity in home and building lighting and HVAC control applications. It is ideal for large sensor networks because of its ability to extend the range and reliability of the network by using mesh networking. ZigBee's growing list of standard profiles has help expand its use in dozens of new products. According to Bob Heile, chairman of the ZigBee Alliance, the latest ZigBee push is its advanced metering infrastructure (AMI) initiative into the utilities for remote meter reading. Along with the utilities industry, ZigBee is part of a new Home Area Network (HAN) plan that could let the electric and gas utilities monitor and control the electricity and gas usage in the home. This can bring about great new energy efficiency programs that consumers can subscribe to. For a look at some short-range wireless video technologies, read: Competition For A Wireless Video Home Heats Up.

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