Method and arrangement for transmitting and recieving rf signals through various radio interfaces of communication systems

Abstract

A method and arrangement for transmitting and receiving RF signals, associated with different radio interfaces of communication systems, employ a direct conversion based transceiver which substantially comprises one receive signal branch and one transmit signal branch. Mixing frequencies of the different systems are generated by a single common by use of an output frequency divider in combination with the synthesizer, and by use of filtering corresponding to a system channel bandwith by means of a controllable low-pass filter operating at baseband frequency.

1 .- 23 . (canceled)  
   
   
       24 . A method for processing signals received from different radio interfaces of communication systems, the method comprising: 
 receiving a carrier-frequency signal from a radio interface,    bandpass-filtering the signal at the carrier frequency,    amplifying the filtered signal at the carrier frequency,    generating an RX mixing signal at the receive frequency,    generating a complex baseband signal from the received carrier-frequency signal by mixing it with the RX mixing signal,    low pass filtering the baseband signal generated by filters having a controllable higher cut-off frequency, wherein the filtering is performed at a bandwidth corresponding to the selected radio interface,    amplifying or attenuating the baseband signal generated prior to analog-to-digital conversion,    converting the baseband signal to a digital form, and    processing the converted the baseband signal so as to produce an information signal encoded and modulated into the received signal.    
   
   
       25 . A method for processing signals transmitted to different radio interfaces of communication systems, the method comprising: 
 generating a digital baseband quadrature signal on the basis of the information signal to be transmitted,    converting the digital baseband signal to an analog form,    low pass filtering the analog signals by filters having a controllable higher cut-off frequency, wherein the filtering is performed at a bandwidth corresponding to the selected radio interface, generating a TX mixing signal at the transmit frequency,    generating a carrier-frequency transmission signal from the baseband signal by mixing    it with the TX mixing signal, amplifying the carrier-frequency signal generated, and    transmitting the transmission signal to the radio interface.    
   
   
       26 . A direct-conversion receiver operating at different radio interfaces of communication systems, comprising 
 an antenna means for receiving a carrier-frequency signal from a radio interface,    a bandpass filter for filtering the carrier-frequency signal,    a first receiver amplifier for amplifying the filtered carrier-frequency signal,    means for generating an RX mixing signal at the receive frequency,    mixing means for generating a complex baseband signal from the received signal by means of the RX mixing signal,    a low-pass filter for filtering the baseband signal, the low-pass filter having a controllable cut-off frequency, the receiver being arranged to perform filtering at a bandwidth corresponding to the selected radio interface,    a second amplifier for amplifying the baseband signal,    an analog-to-digital converter for converting the baseband signal to a digital form, and    means for processing the converted baseband signal to produce an information signal encoded and modulated into the received signal.    
   
   
       27 . The receiver of  claim 26 , wherein the signal processing parts for processing receive frequency signal are common for signals received from at least two different radio interfaces  
   
   
       28 . The receiver of  claim 26 , comprising means for selecting the pass band of the bandpass filter such that it corresponds to the receive frequency.  
   
   
       29 . The receiver of  claim 26 , comprising means for controlling the gain of said first amplifier.  
   
   
       30 . The receiver of  claim 26 , wherein the means for generating a mixing signal at the receive frequency comprises an RX synthesizer and controllable frequency divider for dividing the frequency of the output signal generated by the RX synthesizer.  
   
   
       31 . The receiver of  claim 30 , wherein said frequency divider is arranged so as to divide the output signal of the RX synthesizer always by at least two in order to generate an RX mixing signal.  
   
   
       32 . The receiver of  claim 26 , further comprising means for implementing channel filtering realized in a digital manner.  
   
   
       33 . The receiver of  claim 26 , further comprising means for controlling the gain of the second amplifier.  
   
   
       34 . The receiver of  claim 33 , wherein the second amplifier realizes automatic gain control.  
   
   
       35 . The receiver of  claim 33 , wherein the second amplifier comprises an offset voltage correction block.  
   
   
       36 . The receiver of  claim 26 , wherein the signal processing path comprises substantially the same components for connecting to the different radio interfaces.  
   
   
       37 . A direct-conversion transmitter operating at different radio interfaces of communication systems, comprising 
 means for generating a digital baseband quadrature signal on the basis of an information signal to be transmitted,    a digital-to-analog converter for converting the baseband transmission signal to an analog form,    a controllable low-pass filter for filtering the baseband transmission signal, the low-pass filter having a controllable cut-off frequency, the transmitter being arranged to perform filtering at a bandwidth corresponding to the selected radio interface,    a synthesizer for generating a TX mixing signal at a transmit frequency,    a mixing means for producing a signal at a carrier frequency from the baseband transmission signal by means of the TX mixing signal,    a transmitter amplifier for amplifying the signal at the carrier frequency, and    antenna means for transmitting the amplified signal at the carrier frequency.    
   
   
       38 . The transmitter of  claim 37 , comprising means for implementing channel filtering realized in a digital manner.  
   
   
       39 . The transmitter of  claim 37 , wherein signal processing parts for processing transmit signals are common for signals transmitted to at least two different radio interfaces  
   
   
       40 . The transmitter of  claim 37 , wherein the means for generating a TX mixing signal at the transmit frequency comprises a TX synthesizer and controllable frequency divider for dividing a frequency of an output signal generated by the TX synthesizer.  
   
   
       41 . The transmitter of  claim 40 , characterized in that the frequency divider is arranged so as to divide the TX synthesizer's output signal always at least by two in order to generate the TX mixing signal.  
   
   
       42 . The transmitter of  claim 37 , comprising means for controlling the gain of the transmitter amplifier.  
   
   
       43 . The transmitter of  claim 42 , wherein the transmitter amplifier realizes automatic gain control.  
   
   
       44 . The transmitter of  claim 37 , comprising means for controlling an operating frequency band of the transmitter amplifier.  
   
   
       45 . The transmitter of  claim 37 , comprising a bandpass filter for filtering the amplified signal at the carrier frequency, and means for selecting the pass band of the transmitter bandpass filter so that it corresponds to the transmission frequency.  
   
   
       46 . The transmitter of  claim 37 , wherein the signal processing path comprises substantially the same components for connecting to the different radio interfaces.