Interference cancellation in microwave backhaul systems

Abstract

A first microwave backhaul assembly comprises a first antenna, a front-end circuit, an inter-backhaul-assembly interface circuit, and an interference cancellation circuit. The first antenna is operable to receive a first microwave signal. The front-end circuit is operable to convert the first microwave signal to a lower-frequency digital signal, wherein the lower-frequency digital signal has energy of a second microwave signal and energy of a third microwave signal. The inter-backhaul-assembly interface circuit is operable to receive information from a second microwave backhaul assembly. The interference cancellation circuit is operable to use the information received via the inter-backhaul-assembly interface circuit during processing of the lower-frequency digital signal to remove, from the first microwave signal, the energy of the third microwave signal. The information received via the inter-backhaul-assembly interface may comprise a signal having energy of the second microwave signal.

What is claimed is: 
     
       1. A system comprising:
 a first microwave backhaul assembly comprising:
 a first antenna operable to receive a first microwave signal; 
 a front-end circuit operable to convert said first microwave signal to a lower-frequency digital signal, wherein said lower-frequency digital signal has energy of a second microwave signal and energy of a third microwave signal; 
 an inter-backhaul-assembly interface circuit operable to receive information from a second microwave backhaul assembly; and 
 an interference cancellation circuit operable to use said information received via said inter-backhaul-assembly interface circuit during processing of said lower-frequency digital signal to remove, from said first microwave signal, said energy of said third microwave signal. 
 
 
     
     
       2. The system of  claim 1 , wherein said information received via said inter-backhaul-assembly interface comprises a signal having energy of said second microwave signal. 
     
     
       3. The system of  claim 1 , wherein said information received via said inter-backhaul-assembly interface comprises a signal having energy of said third microwave signal. 
     
     
       4. The system of  claim 1 , wherein said information received via said inter-backhaul-assembly interface comprises an indication of an amount of energy of said third microwave signal received by said second microwave backhaul assembly. 
     
     
       5. The system of  claim 1 , wherein:
 said second microwave signal is destined for said first microwave backhaul assembly; and 
 said third microwave signal is destined for said second microwave backhaul assembly. 
 
     
     
       6. The system of  claim 1 , wherein said first antenna and a second antenna of said second microwave backhaul assembly are adjacent to one another such that one or more radiation lobes of said first antenna overlap with one or more radiation lobes of said second antenna. 
     
     
       7. The system of  claim 6 , wherein said first antenna and said second antenna of said second microwave backhaul assembly are mounted to the same support structure. 
     
     
       8. The system of  claim 6 , wherein
 said first antenna comprises a first parabolic reflector; 
 said second antenna comprises a second parabolic reflector; 
 said first parabolic reflector and said second parabolic reflector are mounted facing away from each other on a support structure. 
 
     
     
       9. The system of  claim 1 , wherein said inter-backhaul-assembly interface circuit is operable to output said lower-frequency digital signal to a destination external to said first microwave backhaul assembly. 
     
     
       10. The system of  claim 1 , wherein:
 said front-end circuit is operable to measure a performance metric for said first microwave signal; and 
 said inter-backhaul-assembly interface circuit is operable to output said measured performance metric to a destination external to said first microwave backhaul assembly. 
 
     
     
       11. A method comprising:
 receiving, via a first antenna of a first microwave backhaul assembly, a first microwave signal; 
 converting, via a front-end circuit of said first microwave backhaul assembly, said first microwave signal to a lower-frequency digital signal, wherein said lower-frequency digital signal has energy of a second microwave signal and energy of a third microwave signal; 
 receiving, via an inter-backhaul-assembly interface circuit of said first microwave backhaul assembly, information from a second microwave backhaul assembly; and 
 processing, by an interference cancellation circuit of said first microwave backhaul assembly using said information received via said inter-backhaul-assembly interface circuit, said lower-frequency digital signal to remove said energy of said third microwave signal. 
 
     
     
       12. The method of  claim 11 , wherein said information received via said inter-backhaul-assembly interface comprises a signal having energy of said second microwave signal. 
     
     
       13. The method of  claim 11 , wherein said information received via said inter-backhaul-assembly interface comprises a signal having energy of said third microwave signal. 
     
     
       14. The method of  claim 11 , wherein said information received via said inter-backhaul-assembly interface comprises an indication of an amount of energy of said third microwave signal received by said second microwave backhaul assembly. 
     
     
       15. The method of  claim 11 , wherein:
 said second microwave signal is destined for said first microwave backhaul assembly; and 
 said third microwave signal is destined for said second microwave backhaul assembly. 
 
     
     
       16. The method of  claim 11 , wherein said first antenna and a second antenna of said second microwave backhaul assembly are adjacent to one another such that one or more radiation lobes of said first antenna overlap with one or more radiation lobes of said second antenna. 
     
     
       17. The method of  claim 16 , wherein said first antenna and said second antenna of said second microwave backhaul assembly are mounted to the same support structure. 
     
     
       18. The method of  claim 16 , wherein
 said first antenna comprises a first parabolic reflector; 
 said second antenna comprises a second parabolic reflector; 
 said first parabolic reflector and said second parabolic reflector are mounted facing away from each other on a support structure. 
 
     
     
       19. The method of  claim 11 , comprising outing, by said inter-backhaul-assembly interface circuit, said lower-frequency digital signal to a destination external to said first microwave backhaul assembly. 
     
     
       20. The method of  claim 1 , comprising:
 measuring, by said front-end circuit, a performance metric for said first microwave signal; and 
 outputting, by said inter-backhaul-assembly interface circuit, said measured performance metric to a destination external to said first microwave backhaul assembly.