Determining propagation delay of communications in distributed antenna systems, and related components, systems, and methods

• US 9,369,222 B2
• Filed: 11/09/2015
• Issued: 06/14/2016
• Est. Priority Date: 04/29/2011
• Status: Active Grant

• Current Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Original Assignee: Corning Optical Communications LLC (Corning Incorporated)
• Inventors: Berlin, Igor, Pikula, Dragan, Sauer, Michael, Schmidt, Gerald B.
• Primary Examiner(s): DOBSON, DANIEL G
• Application Number:
  US14/936,007
• Publication Number:
  US 20160065320A1
• Time in Patent Office: 218 Days
• US Class Current: 1/1
• CPC Class Codes: H04B 10/25753 Distribution optical network, e.g. between a base station and a plurality of remote units
• CPC Class Codes: H04B 10/25758 between a central unit and a single remote unit by means of an optical fibre
• CPC Class Codes: H04B 10/25759 Details of the reception of RF signal or the optical conversion before the optical fibre
• CPC Class Codes: H04B 17/104 of other parameters, e.g. DC offset, delay or propagation times
• CPC Class Codes: H04B 17/40 of relay systems
• CPC Class Codes: H04B 7/155 Ground-based stations H04B7/204 takes precedence
• CPC Class Codes: H04W 56/004 compensating for timing error of reception due to propagation delay
• CPC Class Codes: H04W 56/0055 determining timing error of reception due to propagation delay
• CPC Class Codes: H04W 56/0065 using measurement of signal travel time
• CPC Class Codes: H04W 64/006 with additional information processing, e.g. for direction or speed determination
• CPC Class Codes: H04W 88/085 Access point devices with remote components

Abstract

Components, systems, and methods for determining propagation delay of communications in distributed antenna systems are disclosed. The propagation delay of communications signals distributed in the distributed antenna systems is determined. If desired, the propagation delay(s) can be determined on a per remote antenna unit basis for the distributed antenna systems. The propagation delay(s) can provided by the distributed antenna systems to a network or other system to be taken into consideration for communications services or operations that are based on communications signal delay. As another non-limiting example, propagation delay can be determined and controlled for each remote antenna unit to uniquely distinguish the remote antenna units. In this manner, the location of a client device communicating with a remote antenna unit can be determined within the communication range of the remote antenna unit.

Claims

1. A communications system, comprising:

a distributed antenna system, comprising;

at least one downlink radio frequency (RF) interface configured to receive downlink RF signals from a base station and distribute the downlink RF signals over at least one downlink communications medium to one or more remote antenna units (RAUs) to be communicated to one or more client devices;

at least one uplink RF interface configured to receive uplink RF signals over at least one uplink communications medium from the one or more RAUs communicated by the one or more client devices to the one or more RAUs; and

a propagation delay generator configured to add propagation delay to the at least one uplink communications medium;

at least one propagation delay measurement circuit communicatively coupled to the at least one downlink RF interface and the at least one uplink RF interface, the at least one propagation delay measurement circuit configured to measure propagation delay of the received uplink RF signals from the one or more client devices by the at least one uplink RF interface in response to the downlink RF signals; and

a controller communicatively coupled to the at least one propagation delay measurement circuit, the controller configured to determine the location of the one or more client devices as a function of determined propagation delay of the received uplink RF signals from the one or more client devices.

2. The communications system of claim 1, wherein the distributed antenna system further comprises a head-end unit comprising:

the at least one downlink RF interface configured to receive the downlink RF signals from the base station and distribute the downlink RF signals over at least one downlink communications medium to the one or more RAUs to be communicated to the one or more client devices; and

the at least one uplink RF interface configured to receive the uplink RF signals over the at least one uplink communications medium from the one or more RAUs communicated by the one or more client devices to the one or more RAUs;

each of the one or more RAUs configured to;

receive the downlink RF signals from the head-end unit over the at least one downlink communications medium;

communicate the received downlink RF signals to the one or more client devices;

receive the uplink RF signals from the one or more client devices; and

distribute the received uplink RF signals over the at least one uplink communications medium to the head-end unit.

3. The communications system of claim 1, wherein the propagation delay generator is further configured to add propagation delay to the at least one downlink communications medium.

4. The communications system of claim 3, wherein the propagation delay generator is configured to equalize the propagation delay between each of the at least one downlink communications medium and the at least one uplink communications medium.

5. The communications system of claim 1, wherein the at least one propagation delay measurement circuit is further configured to measure propagation delay of the received downlink RF signals from the base station to the one or more RAUs.

6. The communications system of claim 5, wherein the controller is further configured to determine a location of the one or more client devices as a function of determined propagation delay of the received downlink RF signals from the base station to the one or more RAUs.

7. The communications system of claim 1, wherein the at least one downlink communications medium and the at least one uplink communications medium includes at least one optical fiber medium.

8. The communications system of claim 6, wherein the at least one downlink communications medium and the at least one uplink communications medium includes at least one electrical conductor medium.

9. The communications system of claim 1, wherein the at least one downlink communications medium and the at least one uplink communications medium includes at least one air media.

10. The communications system of claim 1, wherein the at least one propagation delay measurement circuit is located in the base station.

11. The communications system of claim 1, wherein the at least one propagation delay measurement circuit is located in at the at least one downlink RF interface.

12. The communications system of claim 1, wherein the at least one downlink RF interface is comprised of at least one radio interface module configure to receive the downlink RF signals from the base station, filter the received downlink RF signals, and and distribute the filtered downlink RF signals as the downlink RF signals over the at least one downlink communications medium to the one or more RAUs.

13. The communications system of claim 1, further comprising at least one optical RF interface providing at least a portion of the at least one downlink RF interface and the at least one uplink RF interface, the at least one optical RF interface configured to:

receive the downlink RF signals as downlink electrical RF signals;

convert the received downlink electrical RF signals to downlink optical RF signals;

receive the uplink RF signals from the one or more RAUs as uplink optical RF signals; and

convert the received uplink optical RF signals into uplink electrical RF signals.

14. The communications system of claim 13, wherein the at least one propagation delay measurement circuit is located at the at least one optical RF interface to measure the propagation delay between the at least one downlink RF interface and an RAU among the one or more RAUs.

15. The communications system of claim 1, wherein the at least one propagation delay measurement circuit is comprised of a plurality of propagation delay measurement circuits, each of the plurality of propagation delay measurement circuits communicatively coupled to one downlink RF interface among the at least one downlink RF interface and one uplink RF interface among the at least one uplink RF interface.

16. The communications system of claim 1, wherein the controller is further configured to communicate to an RAU among the one or more RAUs over the at least one downlink communications medium to return received downlink RF signals as uplink RF signals to the at least one uplink RF interface.

17. A method of determining a location of a client device in a distributed antenna system, comprising:

receiving downlink radio frequency (RF) signals from a base station;

distributing the downlink RF signals over at least one downlink communications medium to one or more remote antenna units (RAUs) to be communicated to one or more client devices;

receiving uplink RF signals over at least one uplink communications medium from the one or more RAUs communicated by the one or more client devices to the one or more RAUs; and

adding propagation delay to the at least one uplink communications medium;

measuring propagation delay of the received uplink RF signals from the one or more client devices in response to the downlink RF signals; and

determining the location of the one or more client devices as a function of determined propagation delay of the received uplink RF signals from the one or more client devices.

18. The method of claim 17, further comprising adding propagation delay to the at least one downlink communications medium.

19. The method of claim 18, further comprising equalizing the propagation delay between each of the at least one downlink communications medium and the at least one uplink communications medium.

20. The method of claim 17, further comprising measuring propagation delay of the received downlink RF signals from the base station to the one or more RAUs.

21. The method of claim 20, further comprising determining a location of the one or more client devices as a function of determined propagation delay of the received downlink RF signals from the base station to the one or more RAUs.

22. The method of claim 17, comprising determining the location of the one or more client devices as a function of determined propagation delay of the received uplink RF signals from the one or more client devices, in a base station.

23. The method of claim 17, comprising measuring the propagation delay of the received uplink RF signals from the one or more client devices in response to the downlink RF signals, in the distributed antenna system.