Reference signal communication method and system

A method of transmitting an overall composite signal to a receiver including a data modulated signal and a varying reference signal, the method comprising the steps of:

• modulating source message bits so as to generate the data modulated subcarrier signal;
• generating a modulated reference signal which varies from reference signal baud interval to reference signal baud interval in a predetermined manner as a function of a sequence of reference values thereby reducing the effects of non-linearity and stationary interference on the recovery of the reference signal in the receiver;
• summing the data modulated signal and the modulated reference signal to form an overall composite signal;
• and
• transmitting the overall composite signal to the receiver.

A method of receiving an overall composite signal including a modulated reference signal and a data modulated signal, the reference signal having been modulated in a corresponding transmitter, the method comprising the steps of:

• receiving the overall composite signal including the data modulated signal, and the modulated reference signal which varies from reference signal baud interval to reference signal baud interval in a predetermined manner;
• substantially cancelling the effect of the modulation in the reference signal so as to form a substantially unmodulated reference signal;
• accumulating the unmodulated reference signal in order to determine a reference signal estimate;
• and
• using the reference signal estimate to facilitate at least one of equalization, carrier recovery, and baud clock recovery thereby reducing the effects of at least one of non-linearity and stationary interference on the recovery of the reference signal in the receiver.

A receiver for receiving an overall composite signal including a varying reference signal and at least one data modulated signal, the reference signal varying from reference signal baud interval to reference signal baud interval in a predetermined manner as determined by a sequence of reference values in a corresponding transmitter, the receiver comprising:

• means for receiving the overall composite signal including the varying reference signal and a data modulated signal;
• means for cancelling the effect of the sequence of references values in the reference signal so as to form a non-varying reference signal;
• an accumulator for accumulating the non-varying reference signal in order to determine a reference signal estimate;
• and
• means for using the reference signal estimate for one of clock synchronization and equalization.

A method of receiving and processing a modulated reference signal from a transmitter, the method comprising the steps of:

• receiving the modulated reference signal which varies from reference signal baud interval to reference signal baud interval as determined by a sequence of reference values in the transmitter;
• substantially cancelling the effect of the modulation of the reference signal so as to form a substantially unmodulated reference signal;
• accumulating the substantially unmodulated reference signal in order to determine a reference signal estimate thereby reducing the effect of non-linearity on the recovery of the reference signal;
• and
• using the determined reference signal estimate for at least one of equalization, synchronization, and channel characteristic determination.