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Interference Rejection and Channel Detection in Mobile Communication

Nordström, Fredrik LU (2004)
Abstract
This thesis is devoted to statistical problems in mobile communication, in particular disturbance rejection and change detection are studied. Co-channel interference is a significant problem for systems based on TDMA, e.g. EDGE. We show methods for detection and suppression of such interference, when the terminal is equipped with only one antenna. Our algorithms are able to detect an interferer for practically relevant values of C/I and SNR. Further, we are able to estimate the interferering radio channel by correlation techniques and Kalman filters operating in a Viterbi decoder. After the channel is estimated the interference is suppressed by using joint Viterbi decoding or approximations of joint Viterbi decoding.



The... (More)
This thesis is devoted to statistical problems in mobile communication, in particular disturbance rejection and change detection are studied. Co-channel interference is a significant problem for systems based on TDMA, e.g. EDGE. We show methods for detection and suppression of such interference, when the terminal is equipped with only one antenna. Our algorithms are able to detect an interferer for practically relevant values of C/I and SNR. Further, we are able to estimate the interferering radio channel by correlation techniques and Kalman filters operating in a Viterbi decoder. After the channel is estimated the interference is suppressed by using joint Viterbi decoding or approximations of joint Viterbi decoding.



The radio channel for WCDMA system is subject to abrupt and fast changes, which are important to model and detect. We investigate two cases, disappearance of channel paths and appearance of new channel paths. The first case is solved by examining the tap power and alarm if it has been low during a long time. The algorithm is extended with another algorithm that uses the continuity property of a Rayleigh fading channel and locally approximates it by low order polynomials. For the second case three different methods are presented. The first one compares two different variance estimates. The second one is based on that the sum of thresholded residuals, within a window, is binomial distributed. The third method is based on the two sample Kolmogorov-Smirnov test. For both cases it is possible to quickly detect an abrupt path change, within 20-40 CPICH symbols. The mean time between two consecutive false alarms is designed to be the common time between two consecutive path searches. (Less)
Please use this url to cite or link to this publication:
author
opponent
  • Prof. Gustafsson, Fredrik, Institutionen för Systemteknik, Linköpings Universitet
organization
publishing date
type
Thesis
publication status
published
subject
keywords
detection of abrupt changes, WCDMA, Viterbi decoder, Kalman filter, co-channel interference, TDMA, EDGE, Mathematics, Matematik
pages
200 pages
publisher
Mathematical Statistics, Centre for Mathematical Sciences, Lund University
defense location
Matematikcentrum, Sölvegatan 18, room MH:C, Lund Institute of Technology
defense date
2004-02-27 13:15
ISSN
1404-0034
ISBN
91-628-5967-6
language
English
LU publication?
yes
id
2b0b3944-51be-40b2-9d42-9612a6a1a7c6 (old id 21598)
date added to LUP
2007-05-28 14:13:13
date last changed
2016-09-19 08:44:53
@phdthesis{2b0b3944-51be-40b2-9d42-9612a6a1a7c6,
  abstract     = {This thesis is devoted to statistical problems in mobile communication, in particular disturbance rejection and change detection are studied. Co-channel interference is a significant problem for systems based on TDMA, e.g. EDGE. We show methods for detection and suppression of such interference, when the terminal is equipped with only one antenna. Our algorithms are able to detect an interferer for practically relevant values of C/I and SNR. Further, we are able to estimate the interferering radio channel by correlation techniques and Kalman filters operating in a Viterbi decoder. After the channel is estimated the interference is suppressed by using joint Viterbi decoding or approximations of joint Viterbi decoding.<br/><br>
<br/><br>
The radio channel for WCDMA system is subject to abrupt and fast changes, which are important to model and detect. We investigate two cases, disappearance of channel paths and appearance of new channel paths. The first case is solved by examining the tap power and alarm if it has been low during a long time. The algorithm is extended with another algorithm that uses the continuity property of a Rayleigh fading channel and locally approximates it by low order polynomials. For the second case three different methods are presented. The first one compares two different variance estimates. The second one is based on that the sum of thresholded residuals, within a window, is binomial distributed. The third method is based on the two sample Kolmogorov-Smirnov test. For both cases it is possible to quickly detect an abrupt path change, within 20-40 CPICH symbols. The mean time between two consecutive false alarms is designed to be the common time between two consecutive path searches.},
  author       = {Nordström, Fredrik},
  isbn         = {91-628-5967-6},
  issn         = {1404-0034},
  keyword      = {detection of abrupt changes,WCDMA,Viterbi decoder,Kalman filter,co-channel interference,TDMA,EDGE,Mathematics,Matematik},
  language     = {eng},
  pages        = {200},
  publisher    = {Mathematical Statistics, Centre for Mathematical Sciences, Lund University},
  school       = {Lund University},
  title        = {Interference Rejection and Channel Detection in Mobile Communication},
  year         = {2004},
}