Telecommunications – Transmitter and receiver at separate stations – Plural transmitters or receivers
Patent
1997-02-19
2000-07-04
Bost, Dwayne D.
Telecommunications
Transmitter and receiver at separate stations
Plural transmitters or receivers
455501, 455506, 375346, H04B 1500
Patent
active
060851031
ABSTRACT:
A fading compensation apparatus and method are provided in which blocks of the analog AM signal (e.g., voice) are time-compressed at a transmitter. Gaps in the time-compressed signal are filled with pilot symbols (or similar complex waveforms) having known characteristics, such as predetermined amplitudes. The time-compressed analog AM signal (e.g., SSB or VSB) is transmitted over the fading channel. At an analog AM receiver, an estimate of the fading that occurred in the transmission channel is made by observing the amplitude of the received pilot symbols at discrete points in time, and interpolating to determine the amount of fading that occurred across the total transmitted signal. A fading compensator compares the received faded time-compressed signal with the interpolation results, and adjusts the amplitude and phase of the received signal accordingly to compensate for the fading that occurred in the transmission channel. The compensated analog AM signal is time expanded and output to a user.
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An Analysis of Pilot Symbol Assisted Modulation for Rayleigh Fading Channels by James K. Cavers, Member, IEEE, vol. 40, No. 4, Nov. 1991.
Chennakeshu Sandeep
Ramesh Rajaram
Bost Dwayne D.
Ericsson Inc.
Trinh Sonny
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