Remote radio head unit system with wideband power amplifier

Abstract

A remote radio head. unit (RRU) system for multiple operating frequency bands, multi-channels, driven by a single or more wide band power amplifiers. More specifically, the present invention enables multiple-bands RRU to use fewer power amplifiers in order to reduce size and cost of the multi-band RRU. The present invention is based on the method of using duplexers and/or interference cancellation system technique to increase the isolation between the transmitter signal and receiver signal of the RRU.

1 . (canceled) 
     
     
         2 . A remote radio unit (RRU) comprising:
 a transmit path having at least one input at a first end of the transmit path and being coupled to an antenna at a second end of the transmit path, wherein the transmit path is configured to receive at least one first signal via the at least one input and to transmit at least one second signal via the antenna;   a receive path being coupled to the antenna at a first end of the receive path and having at least one output at a second end of the receive path, wherein the receive path is configured to receive at least one third signal via the antenna and to transmit at least one fourth signal via the at least one output; and   a cancellation path being coupled to each of the transmit path and the receive path, wherein the cancellation path is configured to:
 receive at least one fifth signal from the transmit path; 
 receive at least one sixth signal from the receive path; 
 generate, by an interference cancellation unit of the cancellation path, at least one seventh signal based on the at least one fifth signal and the at least one sixth signal; and 
 add the at least one seventh signal to the receive path. 
   
     
     
         3 . The RRU of  claim 2 , wherein the interference cancellation unit is configured to generate the at least one seventh signal based on:
 an upper signal of the at least one fifth signal at a first frequency band;   a lower signal of the at least one fifth signal at a second frequency band that is distinct from the first frequency band;   an upper signal of the at least one sixth signal at the first frequency band; and   a lower signal of the at least one sixth signal at the second frequency.   
     
     
         4 . The RRU of  claim 2 , wherein the interference cancellation unit includes at least one delay block operable to delay the at least one fifth signal with respect to the at least one sixth signal. 
     
     
         5 . The RRU of  claim 2 , wherein:
 the at least one fifth signal is equivalent to or related to the at least one first signal;   the at least one second signal is equivalent to or related to the at least one first signal;   the at least one fourth signal is equivalent to or related to the at least one third signal; and   the at least one sixth signal is equivalent to or related to the at least one third signal.   
     
     
         6 . The RRU of  claim 2 , wherein the transmit path and the receive path are coupled to the antenna via a circulator. 
     
     
         7 . The RRU of  claim 2 , wherein the transmit path and the receive path are coupled to the antenna via a duplexer. 
     
     
         8 . The RRU of  claim 2 , wherein the at least one seventh signal is added to the at least one third signal in the receive path. 
     
     
         9 . The RRU of  claim 2 , wherein the transmit path includes a power amplifier operable to amplify the at least one first signal. 
     
     
         10 . The RRU of  claim 2 , wherein the at least one fifth signal includes multiple signals distributed over a first frequency band and a second frequency band. 
     
     
         11 . The RRU of  claim 2 , wherein the at least one sixth signal includes multiple signals distributed over a first frequency band and a second frequency band. 
     
     
         12 . A method for operating a remote radio unit (RRU), the method comprising:
 receiving, via at least one input at a first end of a transmit path of the RRU, at least one first signal;   transmitting, via an antenna at a second end of the transmit path, at least one second signal;   receiving, via the antenna at a first end of a receive path of the RRU, at least one third signal;   transmitting, via at least one output at a second end of the receive path, at least one fourth signal;   receiving, by a cancellation path of the RRU coupled to each of the transmit path and the receive path, at least one fifth signal from the transmit path;   receiving, by the cancellation path, at least one sixth signal from the receive path;   generating, by an interference cancellation unit of the cancellation path, at least one seventh signal based on the at least one fifth signal and the at least one sixth signal; and   adding, by the cancellation path, the at least one seventh signal to the receive path.   
     
     
         13 . The method of  claim 12 , wherein the interference cancellation unit is configured to generate the at least one seventh signal based on:
 an upper signal of the at least one fifth signal at a first frequency band;   a lower signal of the at least one fifth signal at a second frequency band that is distinct from the first frequency band;   an upper signal of the at least one sixth signal at the first frequency band; and   a lower signal of the at least one sixth signal at the second frequency.   
     
     
         14 . The method of  claim 12 , wherein the interference cancellation unit includes at least one delay block operable to delay the at least one fifth signal with respect to the at least one sixth signal. 
     
     
         15 . The method of  claim 12 , wherein:
 the at least one fifth signal is equivalent to or related to the at least one first signal;   the at least one second signal is equivalent to or related to the at least one first signal;   the at least one fourth signal is equivalent to or related to the at least one third signal; and   the at least one sixth signal is equivalent to or related to the at least one third signal.   
     
     
         16 . The method of  claim 12 , wherein the transmit path and the receive path are coupled to the antenna via a circulator. 
     
     
         17 . The method of  claim 12 , wherein the transmit path and the receive path are coupled to the antenna via a duplexer. 
     
     
         18 . The method of  claim 12 , wherein the at least one seventh signal is added to the at least one third signal in the receive path. 
     
     
         19 . The method of  claim 12 , wherein the transmit path includes a power amplifier operable to amplify the at least one first signal. 
     
     
         20 . The method of  claim 12 , wherein the at least one fifth signal includes multiple signals distributed over a first frequency band and a second frequency band. 
     
     
         21 . The method of  claim 12 , wherein the at least one sixth signal includes multiple signals distributed over a first frequency band and a second frequency band.