Link-fault tolerance in a distributed antenna system

• US 9,929,980 B2
• Filed: 02/12/2015
• Issued: 03/27/2018
• Est. Priority Date: 05/02/2014
• Status: Active Grant

• Current Assignee: Outdoor Wireless Networks LLC (CommScope Holding Company, Inc.)
• Original Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Inventors: Ranson, Christopher G., Schmalisch, Mathias A., Hanson, Van E.
• Primary Examiner(s): Yao, Kwang B
• Assistant Examiner(s): Jeong, Moo Ryong
• Application Number:
  US14/621,157
• Publication Number:
  US 20150319109A1
• Time in Patent Office: 1,139 Days
• CPC Class Codes: H04B 7/00 Radio transmission systems, i.e. using radiation field H04B10/00, H04B15/00 take precedence
• CPC Class Codes: H04L 1/06 using space diversity
• CPC Class Codes: H04L 12/6418 Hybrid transport
• CPC Class Codes: H04L 2012/5674 Synchronisation, timing recovery or alignment
• CPC Class Codes: H04L 27/2656 Frame synchronisation, e.g. packet synchronisation, time division duplex [TDD] switching point detection or subframe synchronisation
• CPC Class Codes: H04L 49/552 by ensuring the integrity of packets received through redundant connections
• CPC Class Codes: H04L 49/557 Error correction, e.g. fault recovery or fault tolerance
• CPC Class Codes: H04L 69/22 Parsing or analysis of headers
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition

Abstract

Certain features relate to improving the link-fault tolerance in a distributed antenna system (DAS) by utilizing a series of synchronous Ethernet frames. A receiving remote unit or a head-end unit in the DAS can predict the start of incoming Ethernet frames based on frame information extracted from previously received Ethernet frames. For example, a remote unit can be configured to receive one or more Ethernet frames, each of the one or more Ethernet frames including a start-of-frame field. After a period of time corresponding to the frame repetition rate, the remote unit can search for an additional start-of-frame field, indicating the receipt of the next Ethernet frame. The remote unit can extract the payload data from the next Ethernet frame based on the predicted value for the additional start-of-frame field.

Claims

1. A method, comprising:

receiving, by a remote unit of a distributed antenna system, one or more Ethernet frames, each of the one or more Ethernet frames including a start-of-frame field, the one or more Ethernet frames associated with a frame repetition rate;

detecting the start-of-frame field included in a first Ethernet frame of the one or more Ethernet frames;

extracting a payload of a first Ethernet frame of the one or more Ethernet frames based on the detected start-of-frame field included in the first Ethernet frame;

determining, after a period of time corresponding to the frame repetition rate, whether an additional start-of-frame field included in an additional Ethernet frame of the one or more Ethernet frames is detected;

in response to determining that the additional start-of-frame field is not detected, predicting a location of the additional start-of-frame field included in the additional Ethernet frame of the one or more Ethernet frames; and

extracting an additional payload from the additional Ethernet frame based on the predicted location of the additional start-of-frame field.

2. The method of claim 1, wherein the predicted location of the additional start-of-frame field is determined based on the start-of-frame field and the frame repetition rate.

3. The method of claim 1, wherein the payload of the first Ethernet frame and the additional payload of the additional Ethernet frame include wireless communication information, and wherein the remote unit is configured to transmit the wireless communication information within a coverage area.

4. The method of claim 1, further comprising:

determining whether the remote unit detected the additional start-of-frame field;

setting a frame error counter to zero in response to determining that the remote unit detected the additional start-of-frame field; and

incrementing the frame error counter in response to determining that the remote unit did not detect the additional start-of-frame field.

5. The method of claim 4, further comprising:

determining whether the frame error counter exceeds a threshold value;

searching for the additional start-of-frame field by analyzing the one or more Ethernet frames in response to the frame error counter exceeding the threshold value.

6. The method of claim 1, wherein predicting the location of the additional start-of-frame field includes determining an expected amount of time has passed corresponding to the frame repetition rate.

7. The method of claim 1, wherein the payload and the additional payload include digitized analog signals provided by a head-end unit of the distributed antenna system.

8. A head-end unit of a distributed antenna system, comprising:

a processing device; and

a non-transitory computer-readable medium having program code stored thereon, wherein the program code is executable for performing operations comprising;

detecting a start-of-frame field of a first Ethernet frame of one or more Ethernet frames received by the head-end unit, the one or more Ethernet frames associated with a frame repetition rate;

extracting, a payload of the first Ethernet frame of the one or more Ethernet frames based on the detected start-of-frame field of the first Ethernet frame;

determining, after a period of time corresponding to the frame repetition rate, whether an additional start-of-frame field included in an additional Ethernet frame of the one or more Ethernet frames is detected;

in response to determining that the additional start-of-frame field is not detected, predicting a location of the additional start-of-frame field included in the additional Ethernet frame of the one or more Ethernet frames; and

extracting an additional payload from the additional Ethernet frame based on the predicted location of the additional start-of-frame field.

9. The head-end unit of claim 8, wherein the predicted location of the additional start-of-frame field is determined based on the frame repetition rate and the start-of-frame field.

10. The head-end unit of claim 8, wherein the payload of the first Ethernet frame and the additional payload of the additional Ethernet frame include wireless communication information from a remote unit in the distributed antenna system.

11. The head-end unit of claim 8, wherein the program code is further executable for performing operations comprising:

determining whether the head-end unit detected the additional start-of-frame field;

setting a frame error counter to zero in response to determining that the head-end unit detected the additional start-of-frame field; and

incrementing the frame error counter in response to determining that the head-end unit did not detect the additional start-of-frame field.

12. The head-end unit of claim 11, wherein the program code is further executable for performing operations comprising:

determining whether the frame error counter exceeds a threshold value;

searching for the additional start-of-frame field by analyzing the one or more Ethernet frames received by the head-end unit in response to the frame error counter exceeding the threshold value.

13. The head-end unit of claim 8, wherein predicting the location of the additional start-of-frame field includes determining an expected amount of time has passed corresponding to the frame repetition rate.

14. The head-end unit of claim 8, wherein the payload and the additional payload include digitized analog signals provided by a remote unit of the distributed antenna system.

15. A distributed antenna system, comprising:

a head-end unit configured to transmit one or more Ethernet frames, each of the one or more Ethernet frames including a start-of-frame field, the one or more Ethernet frames associated with a frame repetition rate; and

a remote unit communicatively coupled to the head-end unit, the remote unit configured to;

receive a first Ethernet frame of the one or more Ethernet frames transmitted by the head-end unit,

detect a start-of-frame field included in the first Ethernet frame,

extract a payload of the first Ethernet frame based on the detected start-of-frame field included in the first Ethernet frame,

determine, after a period of time corresponding to the frame repetition rate, whether an additional start-of-frame field included in an additional Ethernet frame of the one or more Ethernet frames is detected,

in response to determining that the additional start-of-frame field is not detected, predict a location of the additional start-of-frame field included in the additional Ethernet frame of the one or more Ethernet frames, and

extract an additional payload from the additional Ethernet frame based on the predicted location of the additional start-of-frame field.

16. The distributed antenna system of claim 15, wherein the predicted location of the additional start-of-frame field is determined based on the frame repetition rate and the start-of-frame field.

17. The distributed antenna system of claim 15, wherein the payload of the first Ethernet frame and the additional payload of the additional Ethernet frame include wireless communication information, and wherein the remote unit is configured to transmit the wireless communication information within a coverage area.

18. The distributed antenna system of claim 15, wherein the remote unit is further configured to:

determine whether the remote unit detected the additional start-of-frame field;

set a frame error counter to zero in response to determining that the remote unit detected the additional start-of-frame field, and

increment the frame error counter in response to determining that the remote unit did not detect the additional start-of-frame field.

19. The distributed antenna system of claim 18, wherein the remote unit is further configured to:

determine whether the frame error counter exceeds a threshold value, and

search for the additional start-of-frame field by analyzing the one or more Ethernet frames received by the remote unit in response to the frame error counter exceeding the threshold value.

20. The distributed antenna system of claim 15, wherein the remote unit is configured to predict the location of the additional start-of-frame field by determining an expected amount of time has passed corresponding to the frame repetition rate.