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Mobile Phones Recognize People
By Hui Ma, China Internet Weekly
April 20, 2009 1:00 PM PT

"If two phones are put together, you get double the resources,” said an excited and thoughtful Jacky Shen, Lead Researcher of the Wireless and Networking Group at Microsoft Research Asia, fiddling with two mobile phones. “The two screens can be merged into a bigger one to display videos of higher resolution. Combined bandwidth allows downloading at double the speed. Even keypads can be expanded to enable greater control."

Shen and his team developed the "Lover’s Phones" based on a “two phones as one” idea. They released a paper on this research in 2007 at MobiSys, a top-level international conference on mobile computing and mobile networking system jointly hosted by the American Association for Computing Machinery (ACM) and the Advanced Computer Systems Association (USENIX), and bagged the award for Best Demo.

The team scored a repeat win at MobiSys 2008 with "Throw-to-Share" technology. The innovative technology for file-sharing re-imagined the experience of using mobile devices: just point your cell phone at that of your friend’s and the two phones will be wirelessly connected after two "beeps." With the same “gesture,” the picture you just took with your phone can be displayed on your laptop computer.

Pieces of information can be “thrown” to other devices -- a whole new approach to service-driven mobile networking. Users only need to think about the services they desire, and the system will be responsible for all the networking details. “Throw-to-Share” technology reflects the two principles for research Shen repeatedly referred to during the interview: be cool, and be practical. The magical power of elegantly “throwing” information to an intended recipient has its origins in Shen’s experience as a student.

Inspiration from the Canteen

Like many other innovations at Microsoft Research Asia, the value and significance of Throw-to-Share began in a practical place.

When studying in Hong Kong, Shen had to order food at the school cafeteria by pointing, because he could not speak Cantonese and the senior waitress did not know Mandarin. He found pointing to be very useful when verbal communication failed. Several years later when Shen tried to exchange photos via Bluetooth with one of his friends, the entire process (including file selection, target device selection, transmission and reception confirmation) took more than 10 minutes. Recalling similar "troubles" he had experienced, Shen found inspiration in the method he used to order food at the school cafeteria.

"The first and also the most critical step is to identify each other's cell phones and establish network connection when transferring files using conventional methods like Bluetooth and WiFi, because there may be many other phones around,” explained Shen. “Each device has a unique identification number, but it is very difficult to memorize or to recognize, so people tend to give nicknames to their devices. Such names, however, are creating more problems because they do not follow universal guidelines. You can always find a variety of weird names in a random search for nearby Bluetooth devices. It would be much easier if the process of sharing files among phones is reduced to a pointing gesture – just like what I did in the school cafeteria."

Throw-to-Share technology is based on information about the positions of target devices, which is easily available to users, rather than device names or IP addresses that are difficult for users to recognize or associate to particular devices – the entire connection and authentication process is automatic. Throw-to-Share is a simple and intuitive file-sharing solution for mobile devices, especially to ordinary users with no technical background.

Innovations like these, despite their high-tech and futuristic appearance, come from Microsoft Research Asia researchers’ careful observations of and reflections on daily life experiences -- a bizarre idea might come from playing computer games or a researcher may be hit with a flash of inspiration amid a chat with friends.

Innovative Minimalism

The technical requirements for a mobile phone to "identify" other mobile devices are rather simple: a speaker, a wireless port like Bluetooth and Throw-to-Share software. The method behind this process, though, is not as simple.

In her demonstration, Researcher Chunyi Peng takes a few pictures with her phone before pointing it to one of her colleagues’ phones. Hearing two beeps from Peng’s device, the screen of the target phone begins to flash, as if it has recognized a friend, and alerts its owner that someone would like to share files. A dialog box appears on the flashing screen to ask the owner whether to accept the transmission. A positive answer to this question will automatically start the sharing, with no need to select phone models, or to confirm settings.

How does this pointing gesture let a mobile phone know which target device to lock on?

"This is precisely where the technical difficulty lies," said Shen, explaining that a file sender may not know the name of the target device, but a quick glance will tell him who is holding it. A mobile phone, in contrast, knows the “name” of each of the surrounding devices, but cannot associate it to its owners. A user identifies other devices by their physical position (because the devices are held by their respective owners, and the user knows the position of the owner of the target device), and the ideal situation would be for a mobile phone to be able to do the same.

The pointing gesture is the key to isolating a target phone from other phones in the area. As your phone points at its target device, the distance between your phone and the target phone will change more than the distance between your phone or the target phone and other “non-target” devices. This change in distance signals to the target phone that it is trying to be reached. "Through audio sampling, the mobile phone detects changes in their relative positions by calculating slight difference in the time they ‘hear’ the beeps to further distinguish target devices,” said Shen. “What we feel is rather cool is that we’re using sound, which is so simple a phenomenon, for such a practical purpose."

A Major Mobile Development

At the core of Throw-to-Share is a natural gesture-based technology for secure device connection. This application, merely 30+ KB in size, is likely to be marketed as a new product for mobile devices, or directly included in Windows Mobile as a small feature.

Microsoft Research Asia brought into reality a scenario once believed to be reserved for high-tech sci-fi movies. As a technology enthusiast commented after a presentation of Throw-to-Share: anyone who has seen the movie "Wanted" will easily get excited by this pointing gesture. There is no doubt that information will be commonly passed around this way by 2012. If further extended and combined with a smart home, this technology will give birth to many more useful features. For instance, one may only need to point a mobile phone at a bookcase to load files for browsing on the go instead of manually searching for desired content.

"As researchers, we are anxious to see this technology used by everyone, because it really makes life easier,” said Shen. Microsoft Research Asia has long been encouraging system research following the well-known guiding principle: "Keep it Simple and Stupid." A good system must be simple in theory and easy to use, even though it is technically very complicated. The key to system research is to have a viable idea at its core, backed up by continued improvement in technical details, until an application that is both “cool” and “practical” is developed.

With basic research that generates innovative mobile devices, one can imagine that Microsoft is going to wage war on Apple and Google in a highly "personalized" way.

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