| Author | Le Bao Long |
| Call Number | AIT Thesis no.TC-02-22 |
| Subject(s) | Kalman filtering
Mobile communication systems
|
| Note | A thesis submitted in partial fulfillment of the requirement for the degree of
Master of Engineering, School of Engineering and Technology |
| Publisher | Asian Institute of Technology |
| Series Statement | Thesis ; no. TC-02-22 |
| Abstract | Mobile location estimation has attracted much interest over the past few years due
to its potential for new wireless applications and network performance improvement.
While the most promising technique for mobile location using cellular mobile networks
may be Time Different of Arrival (TDOA) method, the major challenged problems which
inhibit accurate mobile location estimation are multipath and non line of sight (NLOS)
problems. These problems make the estimated range biased from the true range and finally
lead to big errors in mobile location estimates. Range data due to NLOS Base Stations
(BS) can be simply ignored but the number of available BSs may not always be enough
and range data from as many BSs as possible should be used to overcome large location
estimation errors due to undesirable geometric BS layout.
In this thesis, techniques for LOSINLOS detection on a sample per sample basis,
which are called Real Time Mode and Delayed Mode are proposed and suitable range
processing approaches using Kalman filtering are also devised to smooth range data
depending on the LOSINLOS detection result. The proposed techniques for LOSINLOS
recognition and range processing have the advantage that an acceptable delay is used
while other previously proposed techniques using the time historic information of range
data required much delay, which would be unfavorable for real time location applications.
The famous Chan's algorithm is employed to estimate the mobile location using
the processed range data. A further Kalman filter, which was previously proposed by
another author is used to smooth the obtained mobile trajectory. The proposed range
processing technique in a mobile location architecture is tested by running simulations for
different mobile trajectory types under the influence of exponentially distributed and
uniformly distributed NLOS noise.
The obtained location estimation performance was shown to well satisfy the 67%
and 95% error requirements set by US Federal Communications Commission (FCC) in
1999 for straight and zigzag trajectory kinds. For challenged long trajectory, the location
mandates were only violated in completely NLOS or nearly NLOS wireless environments.
The Delayed Mode was also shown to work little better than Real Time Mode in these
tough environments. |
| Year | 2002 |
| Corresponding Series Added Entry | Asian Institute of Technology. Thesis ; no. TC-02-22 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Information and Communications Technologies (DICT) |
| Academic Program/FoS | Telecommunications (TC) |
| Chairperson(s) | Ahmed, Kazi Mohiuddin ; |
| Examination Committee(s) | Erke, Tapio J. ;Fernando, W. A. C. ; |
| Scholarship Donor(s) | Keihin Electric Express Railway Company Limited (KEIKYU); |
| Degree | Thesis (M.Eng.) - Asian Institute of Technology, 2002 |
