Frequency generation in a wireless communication system

Abstract

A communication system extracts a received modulation frequency from baseband modulation. This frequency is used as a reference to control the output of a variable oscillator. The output of the variable oscillator may be used to generate a transmit upconversion frequency, and may also be used to perform a downconversion from IF to baseband during receive operations.

What is claimed is:  
     
         1 . A method of generating a transmit upconversion frequency in a wireless communication system comprising: 
 receiving a modulated carrier;    deriving a signal frequency from the rate at which data is being received over said modulated carrier;    locking an oscillator output frequency to said signal frequency; and    using said oscillator output frequency to generate said transmit upconversion frequency.    
     
     
         2 . The method of  claim 1 , wherein said modulated carrier is modulated at a defined symbol frequency from which said signal frequency is derived.  
     
     
         3 . The method of  claim 2 , wherein said symbol frequency comprises bits encoded as defined phase states, frequency states, amplitude states, or combinations thereof, of the signal frequency.  
     
     
         4 . The method of  claim 1 , further comprising: 
 downconverting said modulated carrier to produce an intermediate frequency signal; and    demodulating said intermediate frequency signal to produce a baseband signal.    
     
     
         5 . The method of  claim 4 , wherein said downconverting to an intermediate frequency signal is performed using a free-running oscillator  
     
     
         6 . The method of  claim 1 , wherein said locking comprises controlling an input voltage to a voltage-controlled-oscillator with a phase or frequency locked loop.  
     
     
         7 . The method of  claim 1 , wherein said modulated carrier is received from a satellite.  
     
     
         8 . A method of generating a transmit upconversion frequency in a wireless communication system comprising: 
 receiving a modulated carrier;    downconverting said modulated carrier to produce an intermediate frequency signal;    demodulating said intermediate frequency signal to produce a baseband signal;    deriving from said baseband signal a signal frequency from the rate at which data is being received over said modulated carrier;    locking an oscillator output frequency to said signal frequency; and    using said oscillator output frequency to generate said transmit upconversion frequency.    
     
     
         9 . In a wireless communication apparatus comprising a transmitter and a receiver, a method of generating a transmit upconversion frequency for use by said transmitter, comprising: 
 extracting a signal frequency related to the symbol frequency or bit rate of received data from a signal received by said receiver;    generating a variable frequency reference signal;    locking said variable frequency reference signal to said signal frequency; and    generating a transmit upconversion signal from said variable frequency reference signal.    
     
     
         10 . The method of  claim 9 , wherein said symbol frequency comprises bits encoded as defined phase states, frequency states, amplitude states, or combinations thereof, of the signal frequency.  
     
     
         11 . In a wireless communication apparatus comprising a transmitter and a receiver, a method of generating a transmission up-conversion frequency, comprising: 
 extracting a signal frequency from a signal received by said receiver, wherein said signal frequency is related to the rate at which data is being received; and    deriving a transmit upconversion frequency from said signal frequency for use by said transmitter.    
     
     
         12 . The method of  claim 11 , wherein said signal frequency corresponds to a symbol frequency.  
     
     
         13 . The method of  claim 12 , wherein said symbol frequency comprises bits encoded as defined phase states, frequency states, amplitude states, or combinations thereof, of the signal frequency.