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.
Claims12
A communication station for communicating multichannel data communications including simultaneously receiving and processing multiple channels of data at independent rates which share the same selected bandwidth comprising:
- a demodulator means for receiving a multichannel data communication signal having multiple data channels at independent data rates on said selected bandwidth;
- despreading means for separating selected channels of data of the received signal and identifying the data rate for each channel;
- a plurality of decoding means;
- each said decoding means decoding a separated channel of the multichannel data communication at an assigned data rate;
- said plurality of decoding means sharing a common decoding memory;
- and
- control means for directing each separated channel to one of said decoding means and assigning that decoding means a data rate responsive to the identification of data rates by said despreading means.
A low-power, high-speed multichannel Viterbi decoder for simultaneously decoding multiple data channels at independent data rates for use in a spread spectrum modulation receiver comprising:
- a decoder interface for receiving at least four data channels, at independent data rates, and for determining the data rate of each channel, each data channel comprising a plurality of symbols wherein a despread data channel having a data rate less than a maximum data rate includes proportional duplicated symbols;
- a Euclidean distance calculation engine for receiving said symbols from said at least four data channels, for computing distances between each said received symbol being decoded and each of four QPSK constellation points, and for outputting the closest of said four QPSK constellation points for each said received symbol;
- at least four add-compare-select (ACS) circuits, coupled to said calculation engine, for processing said constellation points of said at least four data channels at an assigned data rate;
- a state metric memory and a traceback memory, coupled to said ACS circuits, for processing said at least four data channels being decoded;
- an ACS processor, coupled to said ACS circuits,. for coordinating the processing of said ACS circuits;
- a traceback processor, coupled to said ACS circuits, for arriving at a decoded symbol for all data channels;
- and
- a receiver system interface for coupling the multichannel Viterbi decoder with additional processors.
Dependencies are inferred from the claim text.