Method and apparatus for canceling a transmit signal spectrum in a receiver bandwidth

Abstract

A method and apparatus for attenuating a transmit signal spectrum in a receiver bandwidth. The apparatus relates to an adaptive, digital, coherent, spectral canceller. The method comprises digitizing both a corrupted receiver signal and a reference transmit signal and then digitally implementing an adaptive coherent spectral canceller module to suppress a residue transmit spectral signal power within the receiver bandwidth.

What is claimed:  
     
         1 . A transceiver comprising: 
 a receiver direct converter translating a received signal to a baseband of the received signal and digitizing the translated, received signal;    an adaptive canceller comprising a reference direct converter, the reference direct converter outputting a digitized transmit signal reference of a spectral energy of a transmitter within the bandwidth of a receiver; and    a matched filter, wherein the receiver direct converter, the reference direct converter, and the matched filter suppress the spectral energy of the transmitter within the bandwidth of the receiver.    
     
     
         2 . The transceiver of  claim 1 , wherein the transceiver is a full duplex transceiver.  
     
     
         3 . The transceiver of  claim 1 , further comprising a transmit and receive antenna radiator.  
     
     
         4 . The transceiver of  claim 1 , further comprising a transmit antenna radiator and a receive antenna radiator.  
     
     
         5 . The transceiver of  claim 1 , where the receiver direct converter, the reference direct converter, and the matched filter have approximately 90 dB attenuation.  
     
     
         6 . The transceiver of  claim 1 , wherein the receiver direct converter has a sampling rate approximately equal to that of the carrier frequency of interest.  
     
     
         7 . The transceiver of  claim 1 , wherein the reference direct converter has a sampling rate approximately equal to that of the carrier frequency of interest.  
     
     
         8 . The transceiver of  claim 1 , wherein the canceller further comprises an adaptive digital transversal filter adapted to align an amplitude and a phase of the digitized transmit signal reference in a reference path with a transmit signal in a leakage receiver path, the adaptive digital transversal filter outputting an compensated digitized transmit signal reference.  
     
     
         9 . The transceiver of  claim 1 , wherein the transceiver is adapted to cancel interference from other co-sited transmit antennas.  
     
     
         10 . A method of attenuating a transmitter signal spectrum within a bandwidth of a receiver, the method comprising: 
 digitizing a received signal which is corrupted by components of a transmit signal;    creating a digitized reference transmit signal of the transmit signal within the bandwidth of the receiver;    aligning the digitized reference transmit signal in amplitude, phase and time delay with the digitized received signal;    subtracting the digitized reference transmit signal from the digitized received signal to form a residue; and    suppressing a transmitter spectral signal power of the residue within the bandwidth of the receiver.    
     
     
         11 . The method of  claim 10 , further comprising adjusting the transmit signal based on the residue determined by subtracting the digitized reference transmit signal from the digitized received signal.  
     
     
         12 . A transceiver comprising: 
 a duplexer coupled to an antenna;    a receiver receiving a first signal from the duplexer;    a transmitter sending a second signal to the duplexer; and    an adaptive, digital, coherent spectral canceller coupled to the receiver and the transmitter, the canceller attenuating a signal spectrum leakage of the second signal within a bandwidth of the first signal.