Trends in short-range wireless personal area networking (WPAN) technology

posted by Jeffrey Foerster on June 19, 2007

Bluetooth can be considered the first wireless personal area networking (WPAN) technology accepted in the market enabling new usages like hands-free cell phone connectivity, wireless headsets, electronic wallet transactions, and others. For this discussion, WPAN technology is considered to support ranges of less than 10 meters or within a single room, as compared to wireless local area networking (WLAN), enabled by WiFi, which can cover a home.

This year, we should see the introduction of a new high-rate WPAN technology based upon ‘Ultra-wideband’ or UWB radio technology. In particular, new Wireless USB certified devices based upon UWB technology will allow devices to simply replace the USB cable, and several vendors have already been officially certified with expected roll-out later this year or early next year. This new technology will allow devices to exchange files at rates up to 480 Mbps at short range (typically 3 meters or less) matching the same speeds as wired USB 2.0. For those people tracking this area, there has clearly been a lot of hype about UWB technology over the last several years and a number of hurdles it had to overcome, including heated debates in the IEEE 802.15.3a standards body which never converged on a standard; a challenging international regulatory environment in which countries are just now starting to open up spectrum in Europe, Japan, Korea, and elsewhere; and unclear differentiation relative to new WiFi based technologies like IEEE 802.11n.

My purpose here is not to revisit the relative merits of UWB or W-USB technology. Indeed, I believe we live in a multi-radio world which will support demand for Bluetooth, WiFi, and UWB based radios for short-range connectivity in the future as well as new emerging radio technologies which will be discussed next. Looking to the future, though, there are two primarily applications of interest which could drive the need for higher-and-higher throughputs, namely wireless video cable replacement and rapid large-file download.

Clearly, there are significant technical challenges to overcome in order to replace the video cable while maintaining the same quality as the wire. Uncompressed 1080p resolutions require about 3 Gbps rate, which is beyond any wireless technology available today. Some companies are looking to the unlicensed spectrum available in the 57-64 GHz band in the US (similar bands exist in many other countries as well) which promises sufficient capacity to handle these high rates. However, low cost integration, power consumption, and link stability especially when obstacles are involved are still challenges which must be overcome for 60 GHz radio developers to reliably support wireless video transport.

Other companies are looking at combining compression with lower throughput radios like UWB or WiFi, but then video quality, complexity, error resiliency, latency, and methods for dealing with mixed media content expected for PC displays (text, computer graphics, and video) are a challenge. I believe that engineers will be able to overcome these challenges for both 60 GHz radios as well as compression for wireless video/displays, and I believe both elements will be needed in the future as higher resolution displays will continue to push the throughput needs of the radios.

In addition to video, the other application driving the need for high-throughput radios is rapid large file ‘synch-n-go’. How long would you wait to download an HD movie from a kiosk to your laptop or handset before getting on an airplane (a 20 GByte HD movie takes about 27 minutes at 100 Mbps and only 32 seconds at 5 Gbps speeds)? As the patience of consumers continues to shrink, having the ability to download large files quickly becomes more important. In addition, personal and internet based digital video content continues to increase. This will continue to increase the volume of digital content people want to access, and this will drive memory requirements and high-rate interconnect technology needs (both wired and wireless) far into the future.

At the same time, consumers continue to be more mobile, form factors are becoming smaller and smaller, and yet the same experience (and cost) are expected. What new applications, usage models, or device form factors are possible when we are able to replace all wires into a device, even the power cable via wireless power or inductive power? The marketing and business folks will continue to refine platform requirements to make sure they address real consumer problems and desires over time (not just performance and speed, but also issues like ease-of-use, power consumption, security, etc.), but it’s clear that there are significant technical challenges anticipated for future platforms which will help determine what’s possible. So, stay tuned…

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tagged: 802.11n, radio, Ultra-wideband, UWB, Wi-Fi, wireless, WPAN, WUSB