Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Wireless networks: Mobile devices keep track

22.11.2012
A more sensitive technique for determining user position could lead to improved location-based mobile services

Many mobile-phone applications (apps) use spatial positioning technology to present their user with location-specific information such as directions to nearby amenities.

By simultaneously predicting the location of the mobile-user and the data access points, or hotspots, improved accuracy of positioning is now available, thanks to an international research team including Sinno Jialin Pan from the A*STAR Institute for Infocomm Research1. Software developers expect that such improvements will enable a whole new class of apps that can react to small changes in position.

Traditionally, device position was determined by the Global Positioning System (GPS) that uses satellites to triangulate approximate location, but its accuracy falters when the mobile device is indoors. An alternative approach is to use the ‘received signal strength’ (RSS) from local transmitters. Attenuation of radio waves by walls can limit accuracy; and, it is difficult to predict signals in complex, obstacle-filled environments.

Software developers have tried to circumvent these problems by using so-called ‘learning-based techniques’ that identify correlations between RSS values and access-point placement. Such systems do not necessarily require prior knowledge of the hotspot locations; rather they ‘learn’ from data collected on a mobile device. This also has drawbacks: the amount of data can be large, making calibration time consuming. Changes in the environment can also outdate the calibration.

Pan and his co-workers reduced this calibration effort in an experimental demonstration of a protocol that calculates both the positions of the device and the access points simultaneously — a process they call colocalization. “Integrating the two location-estimation tasks into a unified mathematical model means that we can fully exploit the correlations between mobile-device and hotspot position,” explains Pan.

First, the researchers trained a learning-based system with the signal-strength values received from access points at selected places in the area of interest. They used this information to calibrate a probabilistic ‘location-estimation’ system. Then, they approximated the location from the learned model using signal strength samples received in real-time from the access points.

Experimental trials showed that this approach not only required less calibration, but it was more accurate than other state-of-the-art systems. “We next want to apply the method to a larger-scale environment,” says Pan. “We also want to find ways to make use of the estimated locations to provide more useful information, such as location-based advertising.” As this technique could help robots navigate by themselves, it may also have important implications for the burgeoning field of robotics.

The A*STAR-affiliated researchers contributing to this research are from the Institute for Infocomm Research

Journal information

Pan, J. J., Pan, S. J., Yin, J., Ni, L. M. & Yang, Q. Tracking mobile users in wireless networks via semi-supervised colocalization. IEEE Transactions on Pattern Analysis and Machine Intelligence 34, 587–600 (2012).

A*STAR Research | Research asia research news
Further information:
http://www.a-star.edu.sg
http://www.researchsea.com

More articles from Information Technology:

nachricht Secure networks for the Internet of the future
25.08.2016 | Julius-Maximilians-Universität Würzburg

nachricht New microchip demonstrates efficiency and scalable design
23.08.2016 | Princeton University, Engineering School

All articles from Information Technology >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Streamlining accelerated computing for industry

PyFR code combines high accuracy with flexibility to resolve unsteady turbulence problems

Scientists and engineers striving to create the next machine-age marvel--whether it be a more aerodynamic rocket, a faster race car, or a higher-efficiency jet...

Im Focus: X-ray optics on a chip

Waveguides are widely used for filtering, confining, guiding, coupling or splitting beams of visible light. However, creating waveguides that could do the same for X-rays has posed tremendous challenges in fabrication, so they are still only in an early stage of development.

In the latest issue of Acta Crystallographica Section A: Foundations and Advances , Sarah Hoffmann-Urlaub and Tim Salditt report the fabrication and testing of...

Im Focus: Piggyback battery for microchips: TU Graz researchers develop new battery concept

Electrochemists at TU Graz have managed to use monocrystalline semiconductor silicon as an active storage electrode in lithium batteries. This enables an integrated power supply to be made for microchips with a rechargeable battery.

Small electrical gadgets, such as mobile phones, tablets or notebooks, are indispensable accompaniments of everyday life. Integrated circuits in the interiors...

Im Focus: UCI physicists confirm possible discovery of fifth force of nature

Light particle could be key to understanding dark matter in universe

Recent findings indicating the possible discovery of a previously unknown subatomic particle may be evidence of a fifth fundamental force of nature, according...

Im Focus: Wi-fi from lasers

White light from lasers demonstrates data speeds of up to 2 GB/s

A nanocrystalline material that rapidly makes white light out of blue light has been developed by KAUST researchers.

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

The energy transition is not possible without Geotechnics

25.08.2016 | Event News

New Ideas for the Shipping Industry

24.08.2016 | Event News

A week of excellence: 22 of the world’s best computer scientists and mathematicians in Heidelberg

12.08.2016 | Event News

 
Latest News

Symmetry crucial for building key biomaterial collagen in the lab

26.08.2016 | Health and Medicine

Volcanic eruption masked acceleration in sea level rise

26.08.2016 | Earth Sciences

Moth takes advantage of defensive compounds in Physalis fruits

26.08.2016 | Life Sciences

VideoLinks
B2B-VideoLinks
More VideoLinks >>>