The Experts below are selected from a list of 156 Experts worldwide ranked by ideXlab platform

I. Claesson - One of the best experts on this subject based on the ideXlab platform.

  • Notch Filtering of humming GSM mobile Telephone noise
    2005 5th International Conference on Information Communications & Signal Processing, 2005
    Co-Authors: I. Claesson, Andreas Rossholm
    Abstract:

    A common problem in the world's most widespread Cellular Telephone System, the GSM System, is the interfering signal generated in TDMA Cellular telephony. The infamous "bumblebee" is generated by the switching nature of TDMA Cellular telephony, the radio circuits are switched on and off at a rate of approximately 217 Hz (GSM). This paper describes a study of two solutions for eliminating the humming noise with IIR notch filters. The simpler one is suitable for any exterior equipment. This method still suffers from a small residual of the noise, resulting from the IDLE slots of the sending mobile. The more advanced IIR structure for use within the mobile also eliminates this residual

  • Cancellation of humming GSM mobile Telephone noise
    Fourth International Conference on Information Communications and Signal Processing 2003 and the Fourth Pacific Rim Conference on Multimedia. Proceedi, 2003
    Co-Authors: I. Claesson, A. Nilsson
    Abstract:

    A sometimes annoying problem in the most internationally widespread Cellular Telephone System, the GSM System, is an interfering signal generated by the switching nature of TDMA Cellular Telephone System. A humming noise originating from the speech frames, equivalent to 160 samples of data corresponding to 20 ms at 8 kHz sampling rate is sometimes clearly audible. This paper describes a study of two different software solutions designed to suppress such interference internally in the mobile handset. The methods are Notch filtering, which is performed on a sample-per-sample basis, and speech frame noise cancellation, which is an alternative method employing correlators and subtraction, similar to active noise control [(B. Widow and S.D. Stearns, 1985), (M.Kuo and D.R. Morgan, 1996)].

  • GSM TDMA Frame Rate Internal Active Noise Cancellation
    International Journal of Acoustics and Vibration, 2003
    Co-Authors: I. Claesson, A. Nilsson
    Abstract:

    A common problem in the world's most widely-used Cellular Telephone System, the GSM System, is the interfering signal generated by the switching nature of TDMA Cellular telephony in handheld and other terminals. Signals are sent as chunks of data, speech frames, equivalent to 160 samples of data corresponding to 20 ms at sampling rate of 8 kHz. This paper describes a study of two different software solutions designed to suppress such interference internally in the mobile handset. The methods are 1) notch filtering, which is multiplicative in frequency, and 2) subtractive noise cancellation, which is an alternative method employing correlators. The latter solution is a straigtforward, although somewhat unorthodox, application of "in-wire" active noise control. Since subtraction is performed directly in the time domain, and we have access to the state of the mobile, it is also possible to consider a recurring pause in the interference caused by the idle frame in the transmission, when the mobile listens to other base stations communicating. More complex control algorithms, based on the state of the communication between the handset and the base station, can be utilised.

A. Nilsson - One of the best experts on this subject based on the ideXlab platform.

  • Cancellation of humming GSM mobile Telephone noise
    Fourth International Conference on Information Communications and Signal Processing 2003 and the Fourth Pacific Rim Conference on Multimedia. Proceedi, 2003
    Co-Authors: I. Claesson, A. Nilsson
    Abstract:

    A sometimes annoying problem in the most internationally widespread Cellular Telephone System, the GSM System, is an interfering signal generated by the switching nature of TDMA Cellular Telephone System. A humming noise originating from the speech frames, equivalent to 160 samples of data corresponding to 20 ms at 8 kHz sampling rate is sometimes clearly audible. This paper describes a study of two different software solutions designed to suppress such interference internally in the mobile handset. The methods are Notch filtering, which is performed on a sample-per-sample basis, and speech frame noise cancellation, which is an alternative method employing correlators and subtraction, similar to active noise control [(B. Widow and S.D. Stearns, 1985), (M.Kuo and D.R. Morgan, 1996)].

  • GSM TDMA Frame Rate Internal Active Noise Cancellation
    International Journal of Acoustics and Vibration, 2003
    Co-Authors: I. Claesson, A. Nilsson
    Abstract:

    A common problem in the world's most widely-used Cellular Telephone System, the GSM System, is the interfering signal generated by the switching nature of TDMA Cellular telephony in handheld and other terminals. Signals are sent as chunks of data, speech frames, equivalent to 160 samples of data corresponding to 20 ms at sampling rate of 8 kHz. This paper describes a study of two different software solutions designed to suppress such interference internally in the mobile handset. The methods are 1) notch filtering, which is multiplicative in frequency, and 2) subtractive noise cancellation, which is an alternative method employing correlators. The latter solution is a straigtforward, although somewhat unorthodox, application of "in-wire" active noise control. Since subtraction is performed directly in the time domain, and we have access to the state of the mobile, it is also possible to consider a recurring pause in the interference caused by the idle frame in the transmission, when the mobile listens to other base stations communicating. More complex control algorithms, based on the state of the communication between the handset and the base station, can be utilised.

Paul L. Knapp - One of the best experts on this subject based on the ideXlab platform.

  • The NavTrax fleet management System
    IEEE PLANS 92 Position Location and Navigation Symposium Record, 1992
    Co-Authors: James F. Mclellan, Edward J. Krakiwsky, J. B. Schleppe, Paul L. Knapp
    Abstract:

    The NavTrax System, a dispatch-type automatic vehicle location and navigation System, is discussed. Attention is given to its positioning, communication, digital mapping, and dispatch center components. The positioning module is a robust GPS (Global Positioning System)-based System integrated with dead reckoning devices by a decentralized-federated filter, making the module fault tolerant. The error behavior and characteristics of GPS, rate gyro, compass, and odometer sensors are discussed. The communications module, as presently configured, utilizes UHF radio technology, and plans are being made to employ a digital Cellular Telephone System. Polling and automatic smart vehicle reporting are also discussed. The digital mapping component is an intelligent digital single line road network database stored in vector form with full connectivity and address ranges. A limited form of map matching is performed for the purposes of positioning, but its main purpose is to define location once position is determined. >

  • THE NavTraxTM FLEET MANAGEMENT System
    1992
    Co-Authors: James F. Mclellan, Edward J. Krakiwsky, J. B. Schleppe, Paul L. Knapp
    Abstract:

    The NavTraxm System is a dispatch type Automatic Vehicle Location and Navigation (AVLN) System. Discussed in the paper are its positioning, communication, digital mapping, and dispatch centre components. The positioning module is a robust - GPS based System integrated with dead reckoning devices by a decentralized-federated filter making the module fault tolerant. The error behavior and characteristics of GPS, rate gyro, compass and odometer sensors are discussed. The communications module, as presently configured, utilizes UHF radio technology and plans are being made to employ the digital Cellular Telephone System. Polling and automatic "smart vehicle reporting" are also discussed. The digital mapping component is an intelligent digital single line road network data base stored in vector form with full connectivity and address ranges. A limited form of map matching is performed for the purposes of positioning, but, its main purpose is to define "location" once "position" is determined.

Deborah J Shale - One of the best experts on this subject based on the ideXlab platform.

  • Cellular Telephone System that uses position of a mobile unit to make call management decisions
    1995
    Co-Authors: Everett Dennison, Edwin L Nass, Timothy J Duffy, Gregory T Pauley, Scott L Jones, Deborah J Shale
    Abstract:

    A Cellular Telephone System includes a plurality of cell sites and a mobile Telephone switching office. Call management, including selection of a cell site most appropriate for a call associated with a mobile unit, are made based on the geographic location of the mobile unit as opposed to the strength of the signal associated with the call. The geographic location of the mobile unit is precisely determined using a NAVSTAR global positioning System, or its equivalent. Each mobile unit includes a GPS receiver that receives information from a geostationary satellite to determine the precise location of the mobile unit. This position information is relayed to the cell site initially managing the mobile unit, and the mobile unit is handed off to a cell site that is most appropriate for the call. Initial selection of an entrance cell site is made based on signal strength, but further call management decisions are made based on location of the mobile unit.

Andreas Rossholm - One of the best experts on this subject based on the ideXlab platform.

  • Notch Filtering of humming GSM mobile Telephone noise
    2005 5th International Conference on Information Communications & Signal Processing, 2005
    Co-Authors: I. Claesson, Andreas Rossholm
    Abstract:

    A common problem in the world's most widespread Cellular Telephone System, the GSM System, is the interfering signal generated in TDMA Cellular telephony. The infamous "bumblebee" is generated by the switching nature of TDMA Cellular telephony, the radio circuits are switched on and off at a rate of approximately 217 Hz (GSM). This paper describes a study of two solutions for eliminating the humming noise with IIR notch filters. The simpler one is suitable for any exterior equipment. This method still suffers from a small residual of the noise, resulting from the IDLE slots of the sending mobile. The more advanced IIR structure for use within the mobile also eliminates this residual