Multichannel viterbi decoder
AssigneeInterDigital Technology Corporation
InventorJohn D. Kaewell, Jr.
Life of this patent
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Abstract
A communication system where the data rate of a given transmission has been encoded by a transmitter and is then used to adjust a plurality of convolutional decoders sharing common memory. The system uses common processing resources to provide up to four discrete channels having multi-rate convolutional error correction decoding resulting in a reduced silicon area and low power operation. The system is capable of supporting data communication at 8 kbps up to 64 kbps for high rate ISDN communication in receivers of both base station and consumer unit locations.
Claims16
A method for simultaneously receiving a plurality of channel signals in a shared spectrum of a wireless spread spectrum code division multiple access communication system, the system transmitting the channel signals using quadrature phase shift keying modulation, the channel signals having differing data rates and a same transmission data rate, the method comprising:
- receiving signals transmitted over the shared spectrum;
- demodulating the received signals to produce an in-phase intermediate frequency signal and a quadrature phase intermediate frequency signal;
- despreading with a code associated with each channel signal the in-phase and the quadrature phase intermediate frequency signals to produce a despread in-phase and a despread quadrature phase signal for each channel signal;
- for each channel signal having its data rate below the transmission data rate, combining received symbols of the despread in-phase and quadrature phase despread signals so that after the combining that channel's despread in-phase and quadrature phase signals have that channel's data rate;
- and
- simultaneously processing each channel signal's despread in-phase and quadrature phase despread signals after the combining to recover data for each channel signal.
A receiver for simultaneously receiving a plurality of channel signals in a shared spectrum of a wireless spread spectrum code division multiple access communication system, the system transmitting the channel signals using quadrature phase shift keying modulation, the channel signals having differing data rates and a same transmission data rate, the receiver comprising:
- an antenna for receiving signals transmitted over the shared spectrum;
- a first in-phase and quadrature phase mixer for demodulating the received signals to produce an in-phase intermediate frequency signal and a quadrature phase intermediate frequency signal;
- for each channel signal, a second in-phase and quadrature phase mixer for mixing a code associated with that channel signal with the in-phase and the quadrature phase intermediate frequency signals to produce a despread in-phase and quadrature phase signal for each channel signal;
- an interface for each channel having its data rate below the transmission data rate, for combining received symbols of the despread in-phase and quadrature phase despread signals so that after the combining that channel's despread in-phase and quadrature phase signals have that channel's data rate;
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- a decoder for simultaneously processing each channel signal's despread in-phase and quadrature phase despread signals after the combining to recover data for each channel signal.
Dependencies are inferred from the claim text.