Telecommunications Research Laboratories

Telecommunications Research Lab.

Geoffrey G Messier

Witold A Krzymien

Michel T Fattouche

Stephen Lai

Brent Robert Petersen

A system and method is presented where a low-IF architecture can be used to allow existing wireless standards to be used for joint wireless/power-line channel transmission in the provision of diversity communications channels. Diversity combining of wireless and power-line channels can be employed, wherein the input noise to the maximum-likelihood detector can be Class A-distributed. For uncoded BPSK, the BER can be a function of PLC impulsiveness and can improve wireless-only BER by orders of magnitude when PLC SNR &#x3e;10 dB. The error performance can be equivalent to BER of the static PLC channel for low wireless SNR and can improve with a slope of &#x2212;1 at high wireless SNRs. The inflection point between these two regions can occur at approximately 0 dB when PLC noise is Gaussian, and increases above 20 dB as the noise becomes more impulsive.

System and method for providing a wireless/power-line diversity communications channel

Channel coding is used on the forward link of a CDMA cellular telephone network to allow the CDMA mobile channel decoder to perform error correction. On a wireless link, channel code performance is improved by providing the channel decoder with an estimate of the reliability of each received symbol. This reliability information is typically the ratio of desired signal energy to interference plus noise variance at the channel decoder input. This invention improves CDMA mobile channel decoder performance using a new technique for calculating more accurate estimates of the signal to interference plus noise ratio at the input of the mobile channel decoder.

Channel code decoding for the CDMA forward link

Apparatus for locating a mobile phone in a cellular phone system, in which the cellular phone system comprises plural base stations, each base station being associated with a cell, and in which the mobile phone is programmed to communicate signal strength of received signals to the base stations. Each base station, has a processing unit operably connected to the plural base stations by first communications links, the processing unit having as input the received signal strength measurements, the processing unit being programmed to operate upon the received signal strength measurements to solve a channel model equation in which the position of the mobile phone and the path loss exponent of the cell are unknowns and produce as output position location signals representing the position of the mobile phone in the cell, and a user interface operably connected to the processing unit by a second communication link for communicating signals indicative of the position of the mobile phone in the cell. Various algorithms may be used to solve the channel model equation. A method of locating a mobile phone by A) communicating signal strength measurements of signals received by the mobile phone to a processing unit; B) operating upon the signal strength measurements with the processing unit to solve a channel model equation in which the path loss exponent and the position of the mobile phone are unknowns.

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Calgary, Canada

Geoffrey G Messier