Method and apparatus for embedding auxiliary data in a primary data signal

A method for transporting a plurality of auxiliary information signals in a primary data signal, comprising the steps of:

• modulating each of a plurality of pseudorandom noise carriers by at least one different one of said auxiliary information signals to provide a plurality of spread spectrum signals carrying auxiliary information on carrier portions thereof;
• evaluating said primary data signal using subband analysis to estimate its spectral shape;
• subband filtering said plurality of spread spectrum signals in response to said subband analysis to provide the carrier portions of said spread spectrum signals with a spectral shape which simulates the spectral shape of said primary data signal;
• and
• combining the carrier portions with said primary data signal to produce an output signal carrying said auxiliary information signals as noise in said primary data signal.

Apparatus for transporting auxiliary information in a primary data signal for communication to a receiver, comprising:

• means for converting a data stream of said auxiliary information into a spread spectrum signal carrying said information;
• means for evaluating said primary data signal using time domain modeling to obtain an approximation of its spectral shape;
• and
• a time domain synthesizer responsive to said evaluating means for providing a carrier portion of said spread spectrum signal with a spectral shape which simulates the spectral shape of said primary data signal, thereby producing a noise signal containing said auxiliary information to be carried in said primary data signal.

Apparatus for transporting a plurality of auxiliary information streams in a primary data signal, comprising:

• means for converting said plurality of auxiliary information streams into spread spectrum signals;
• means for evaluating said primary data signal to obtain an approximation of its spectral shape;
• and
• means responsive to said evaluating means for providing carrier portions of said spread spectrum signals with a spectral shape which simulates the spectral shape of said primary data signal;
• wherein a combination of said spread spectrum signals is used to provide noise simulating the spectral shape of said primary data signal for carrying said auxiliary information in said primary data signal.

A decoder for recovering auxiliary information carried by a spread spectrum signal that is transported as noise in a primary data signal, said spread spectrum signal including a carrier having a spectral shape which simulates the spectral shape of information contained in said primary data signal, said decoder comprising:

• means for evaluating said primary data signal using time domain modeling to approximate its spectral shape;
• a time domain processor for processing the primary data signal, based on the spectral shape determined therefor, to whiten the spread spectrum carrier contained therein;
• and
• means for demodulating the whitened spread spectrum carrier to recover said auxiliary information.

A decoder for recovering a plurality of auxiliary information streams carried by a spread spectrum signal that is transported as noise in a primary data signal, said spread spectrum signal including a plurality of carriers having a spectral shape which simulates the spectral shape of information contained in said primary data signal, said decoder comprising:

• means for evaluating said primary data signal to determine its approximate spectral shape;
• means for processing the primary data signal, based on the spectral shape determined therefor, to whiten the spread spectrum carriers contained therein;
• and
• means for demodulating the whitened spread spectrum carriers to recover said auxiliary information streams.

A decoder for recovering auxiliary information carried by a spread spectrum signal transported as noise in a primary data signal, comprising:

• means for whitening a spectrum of said primary data signal, said whitening means creating intersymbol interference in said spread spectrum signal;
• and
• a rake receiver for receiving and demodulating said primary data signal from said whitening means;
• wherein:
• said rake receiver has a plurality of fingers for processing different multipaths of said spread spectrum signal when demodulating the received primary data signal, thereby recovering said spread spectrum signal with reduced intersymbol interference in order to obtain said auxiliary information therefrom;
• said spread spectrum signal is provided by modulating a pseudorandom noise carrier by said auxiliary information;
• and
• a carrier portion of said spread spectrum signal has a spectral shape that approximates a spectral shape of said primary data signal.

A data signal embodied in a carrier wave, comprising:

• a primary data signal portion having an associated spectral shape;
• and
• a noise signal portion carried in said primary data signal;
• wherein:
• said noise signal portion comprises a spread spectrum signal carrier that carries auxiliary information;
• said spread spectrum signal carrier has an associated spectral shape which approximates said spectral shape of said primary data signal;
• and
• said spread spectrum signal carrier is provided with the associated spectral shape thereof by filtering said spread spectrum signal carrier with a time domain synthesis filter that is responsive to a time domain model of said spectral shape of said primary data signal.