Timing adjustments for small cell distributed antenna systems

Abstract

A distributed antenna system includes a host unit communicatively coupled to a first service provider interface which receives a first signal from the first service provider interface; and a first remote antenna unit communicatively coupled to the host unit, the first remote antenna unit having a first antenna. A base station to which the distributed antenna system is communicatively coupled is configured with a subscriber access timing window having a minimum allowed delay and a maximum allowed delay. The distributed antenna system is configured so that a first total delay between the host unit and the first remote antenna unit is equal to or greater than the minimum allowed delay. The first antenna of the first remote antenna unit is configured to communicate the first signal to a first subscriber unit.

What is claimed is: 
     
       1. A distributed antenna system comprising:
 a host unit communicatively coupled to a first service provider interface which receives base station external to the distributed antenna system, the host unit configured to receive a first signal from the first service provider interface base station; 
 a first remote antenna unit communicatively coupled to the host unit, the first remote antenna unit having a first antenna; 
 wherein a the base station to which the distributed antenna system is communicatively coupled is configured with a subscriber access timing window having including a time after a minimum allowed delay and before a maximum allowed delay, wherein the base station considers a subscriber to be within range of the base station when an acknowledgement message is received from the subscriber within the subscriber access timing window; 
 wherein the distributed antenna system is configured so that a first total delay between the host unit and the first remote antenna unit is equal to or greater than the minimum allowed delay; and 
 wherein the first antenna of the first remote antenna unit is configured to communicate the first signal to a first subscriber unit, wherein a coverage area of communication from the first antenna of the first remote antenna unit is proportional to is a function of the first total delay. 
 
     
     
       2. The distributed antenna system of  claim 1 , wherein the first total delay comprises at least one of:
 a first inherent delay in the distributed antenna system between the host unit and the first remote antenna unit; 
 a first propagation delay between the host unit and the first remote antenna unit; 
 and 
 a first additional configurable delay. 
 
     
     
       3. The distributed antenna system of  claim 1 , wherein the first total delay comprises a first configurable delay. 
     
     
       4. The distributed antenna system of  claim 1 , wherein a the coverage area of communication from the first antenna of the first remote antenna unit becomes smaller as the first total delay increases. 
     
     
       5. The distributed antenna system of  claim 1 , wherein the first remote antenna unit is communicatively coupled to the host unit via a physical medium. 
     
     
       6. The distributed antenna system of  claim 5 , wherein the physical medium is at least one of a fiber optical cable, a coaxial cable, or twisted pair. 
     
     
       7. The distributed antenna system of  claim 1 , wherein the first remote antenna unit is communicatively coupled to the host unit via a wireless medium. 
     
     
       8. The distributed antenna system of  claim 1 , wherein the first service provider interface base station is configured to output, and receive as input, respective digital baseband data; and
 wherein the first signal is a digital baseband data signal. 
 
     
     
       9. The distributed antenna system of  claim 8 , wherein the respective digital baseband data comprises in-phase digital baseband data and quadrature digital baseband data; and
 wherein the first signal comprises in phase in-phase digital baseband data and quadrature digital baseband data. 
 
     
     
       10. The distributed antenna system of  claim 8 , wherein the host unit further comprises a baseband interface that receives from, and outputs to, the first service provider interface base station respective digital baseband data. 
     
     
       11. The distributed antenna system of  claim 10 , wherein the baseband interface is configured to perform a protocol conversion between a first baseband protocol used by the first service provider interface base station and a second baseband protocol used by the first remote antenna unit. 
     
     
       12. The distributed antenna system of  claim 10 , wherein the baseband interface is configured to multiplex digital baseband data. 
     
     
       13. The distributed antenna system of  claim 1 , wherein the first service provider interface base station is configured to output, and receive as input, radio frequency signals; and
 wherein the first signal is a radio frequency signal. 
 
     
     
       14. The distributed antenna system of  claim 1 , wherein the service provider interface base station interacts with a carrier network via an Internet protocol (IP) network. 
     
     
       15. The distributed antenna system of  claim 1 , wherein the first remote antenna unit is communicatively coupled to the host unit via at least one intermediary device. 
     
     
       16. The distributed antenna system of  claim 15 , wherein the at least one intermediary device comprises an expansion hub. 
     
     
       17. The distributed antenna system of  claim 15 , wherein the distributed antenna system is a hybrid distributed antenna system;
 wherein the at least one intermediary device comprises a remote server unit that interfaces between a digital portion of the distributed antenna system and an analog portion of the distributed antenna system; 
 wherein the digital portion of the distributed antenna system includes digital communication between the host unit and the remote server unit; 
 wherein the remote server unit converts between digital and analog signals; and 
 wherein the analog portion of the distributed antenna system includes analog communication between the remote server unit and the first remote antenna unit. 
 
     
     
       18. The distributed antenna system of  claim 1 , wherein the distributed antenna system is configured to distribute multiple services. 
     
     
       19. The distributed antenna system of  claim 1 , wherein the distributed antenna system is coupled to multiple wireless service providers' networks. 
     
     
       20. The distributed antenna system of  claim 1 , wherein the distributed antenna system is configured for use in at least one of: in-building applications, outdoor applications, enterprise applications, public safety applications, and military applications. 
     
     
       21. The distributed antenna system of  claim 1 , further comprising groups of the remote antenna units that are configurable for local joint beamforming and/or joint transmission groups of cells. 
     
     
       22. The distributed antenna system of  claim 1 , further comprising:
 a second remote antenna unit communicatively coupled to the host unit, the second remote antenna unit having a second antenna; 
 wherein the distributed antenna system is configured so that a second total delay between the host unit and the second remote antenna unit is equal to or greater than the minimum allowed delay; and 
 wherein the second antenna of the second remote antenna unit is configured to communicate the first a second signal to a second subscriber unit. 
 
     
     
       23. The distributed antenna system of  claim 22 , wherein the second total delay comprises at least one of:
 a second inherent delay in the distributed antenna system between the host unit and the second remote antenna unit; 
 a second propagation delay between the host unit and the second remote antenna unit; and 
 a second additional configurable delay. 
 
     
     
       24. The distributed antenna system of  claim 22 , wherein a second coverage area of communication from the second antenna of the second remote antenna unit is proportional to the second total delay. 
     
     
       25. The distributed antenna system of  claim 22 , wherein the second remote antenna unit is communicatively coupled to the host unit via a physical medium. 
     
     
       26. The distributed antenna system of  claim 25 , wherein the physical medium is at least one of a fiber optic cable, a coaxial cable, or twisted pair. 
     
     
       27. The distributed antenna system of  claim 1 , further comprising:
 wherein the host unit is further communicatively coupled to a second service provider interface base station which receives a second signal from the second service provider interface base station; and 
 wherein at least one antenna of the first a second remote antenna unit is configured to communicate the second signal to a second subscriber unit. 
 
     
     
       28. The distributed antenna system of  claim 27 , wherein the second service provider interface base station is configured to output, and receive as input, respective digital baseband data; and
 wherein the second signal is a digital baseband data signal. 
 
     
     
       29. The distributed antenna system of  claim 27 , wherein the second service provider interface base station is configured to output, and receive as input, radio frequency signals; and
 wherein the second signal is a radio frequency signal. 
 
     
     
       30. The distributed antenna system of  claim 27 , wherein the second remote antenna unit is communicatively coupled to the host unit via at least one intermediary device. 
     
     
       31. The distributed antenna system of  claim 1 , further comprising:
 wherein the host unit is further communicatively coupled to a second service provider interface base station which receives a second signal from the service provider interface second base station; 
 a second remote antenna unit communicatively coupled to the host unit, the second remote antenna unit having a second antenna; 
 wherein the distributed antenna system is configured so that a second total delay between the host unit and the second remote antenna unit is equal to or greater than the minimum allowed delay; and 
 wherein the second antenna of the second remote antenna unit is configured to communicate the second signal to a second subscriber unit. 
 
     
     
       32. The distributed antenna system of  claim 31 , wherein the second total delay comprises at least one of:
 a second inherent delay in the distributed antenna system between the host unit and the second remote antenna unit; 
 a second propagation delay between the host unit and the second remote antenna unit; and 
 a second additional configurable delay. 
 
     
     
       33. The distributed antenna system of  claim 31 , wherein the second remote antenna unit is communicatively coupled to the host unit via a physical medium. 
     
     
       34. The distributed antenna system of  claim 31 , wherein the second service provider interface base station is configured to output, and receive as input, respective digital baseband data; and
 wherein the second signal is a digital baseband data signal. 
 
     
     
       35. The distributed antenna system of  claim 31  wherein the second service provider interface base station is configured to output, and receive as input, radio frequency signals; and
 wherein the second signal is a radio frequency signal. 
 
     
     
       36. The distributed antenna system of  claim 31 , wherein the second remote antenna unit is communicatively coupled to the host unit via at least one intermediary device. 
     
     
       37. The distributed antenna system of  claim 36 , wherein the distributed antenna system is a hybrid distributed antenna system;
 wherein the at least one intermediary device comprises a remote server unit that interfaces between a digital portion of the distributed antenna system and an analog portion of the distributed antenna system; 
 wherein the digital portion of the distributed antenna system includes digital communication between the host unit and the second remote server unit; 
 wherein the remote server unit converts between digital and analog signals; and 
 wherein the analog portion of the distributed antenna system includes analog communication between the remote server unit and the second remote antenna unit. 
 
     
     
       38. A method comprising:
 configuring a distributed antenna system to have a first additional delay of signals communicated within the distributed antenna system between a host unit and a first remote antenna unit in addition to a first inherent delay of the signals communicated within the distributed antenna system between a the host unit and a the first remote antenna unit; 
 wherein the distributed antenna system is communicatively coupled to a base station external to the distributed antenna system and configured to receive a first signal from the base station and to propagate a second signal based on the first signal through the distributed antenna system, wherein the base station is configured with a subscriber access timing window having including a time after a minimum allowed delay and before a maximum allowed delay, wherein the base station considers a subscriber to be within range of the base station when an acknowledgement message is received from the subscriber within the subscriber access timing window; 
 wherein a first total delay of the first additional delay and the first inherent delay of the second signal within the distributed antenna system is equal to or greater than the minimum allowed delay; and 
 wherein a coverage area of communication of a third signal from a first antenna of the first remote antenna unit is proportional to is a function of the first total delay, wherein the third signal is based on the second signal. 
 
     
     
       39. The method of  claim 38 , wherein the first inherent delay comprises at least one of a propagation delay between the host unit and the first remote antenna unit. 
     
     
       40. The method of  claim 38 , further comprising transporting signals from the base station through the distributed antenna system via a physical medium. 
     
     
       41. The method of  claim 38 , further comprising communicating digital baseband data between a service provider interface of the base station and the host unit of the distributed antenna system. 
     
     
       42. The method of  claim 38 , further comprising communicating radio frequency signals between a service provider interface of the base station and the host unit of the distributed antenna system. 
     
     
       43. The method of  claim 38 , further comprising:
 configuring a the distributed antenna system to have a second additional delay in addition to a second inherent delay of the distributed antenna system between the host unit and a second remote antenna unit; and 
 wherein a second total delay of the second additional delay and the second inherent delay of the distributed antenna system is equal to or greater than the minimum allowed delay. 
 
     
     
       44. A distributed antenna system comprising:
 a host unit communicatively coupled to a first service provider interface which receives base station external to the distributed antenna system, the host unit configured to receive a first signal from the first service provider interface base station; 
 a first remote antenna unit communicatively coupled to the host unit; 
 wherein a the base station to which the distributed antenna system is communicatively coupled is configured with a subscriber access timing window having including a time after a minimum allowed delay and before a maximum allowed delay, wherein the base station considers a subscriber to be within range of the base station when an acknowledgement message is received from the subscriber within the subscriber access timing window; 
 wherein the distributed antenna system is configured to propagate a second signal based on the first signal between the host unit and the first remote antenna unit so that a first total delay of the second signal propagated between the host unit and the first remote antenna unit is equal to or greater than the minimum allowed delay; and 
 wherein a coverage area of communication of a third signal from a first antenna of the first remote antenna unit is proportional to is a function of the first total delay, wherein the third signal based on the second signal.