DELAY MANAGEMENT FOR DISTRIBUTED COMMUNICATIONS NETWORKS

• US 20090046586A1
• Filed: 08/15/2007
• Published: 02/19/2009
• Est. Priority Date: 08/15/2007
• Status: Active Grant

• Current Assignee: CommScope Technologies, LLC (CommScope Holding Company, Inc.)
• Original Assignee: ADC Telecommunications Incorporated (TE Connectivity Limited)
• Inventors: Stuart, Steven B., Hedin, John M.
• Granted Patent: US 7,948,897 B2
• Time in Patent Office: Days
• US Class Current: 370/236
• CPC Class Codes: H04J 3/0682 by delay compensation, e.g. by compensation of propagation delay or variations thereof, by ranging
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/18 Negotiating wireless communication parameters
• CPC Class Codes: H04W 48/08 Access restriction or access information delivery, e.g. discovery data delivery signalling during connection H04W76/00

Abstract

A method for programming the delay for a node in a communication system is disclosed. The node receives a selected delay value and a signal path delay value indicating a delay for signals communicated to the node. The signal path delay comprises an aggregation of transport delays calculated by each node for segments of the communication system between the node and a host node. The method further calculates an additional delay necessary to meet the selected delay value.

Claims

1. A method for managing delay between nodes in a network having a plurality of nodes coupled together by a plurality of links, the method comprising:

discovering a transport delay value for each of the plurality of links;

at a first one of the plurality of nodes,

generating a signal path delay value for each of the plurality of nodes coupled to the first one of the plurality of nodes using the discovered transport delay value associated with a link of the plurality of links that couples that node to the first one of the plurality of nodes;

passing the generated signal path delay values over the links to the nodes of the plurality of nodes coupled to the first one of the plurality of nodes; and

at each additional node of the plurality of nodes,

storing a received signal path delay value for the additional node to enable management of the delay for the additional node,

generating a signal path delay value for each adjacent node of the plurality of nodes coupled to the additional node using the received signal path delay value and the discovered transport delay value for the link between the additional node and the adjacent node, and

passing the generated signal path delay values over the additional links to the adjacent nodes.

2. The method of claim 1, wherein discovering a transport delay value comprises:

sending a first signal over a link from one node to an adjacent node of the plurality of nodes;

receiving a second signal back over each link from the adjacent node to the one node of the plurality of nodes; and

calculating the transport delay value for the link based on the timing of the sending of the first signal and the receipt of the second signal.

3. The method of claim 2, wherein sending a first signal comprises setting a bit over at least one of a wireless, free space optics, millimeter wave, twisted pair, coaxial, optical fiber, and hybrid fiber interface.

4. The method of claim 2, wherein calculating the transport delay value comprises:

determining a round trip delay between the one node and the adjacent node; and

dividing the round trip delay in half.

5. The method of claim 2, wherein calculating the transport delay value comprises:

communicating the turn-around delay of the adjacent node to the one node;

determining the round trip delay between the one node and the adjacent node;

subtracting the turn-around delay from the round trip delay to produce a corrected round trip delay; and

dividing the corrected round trip delay by two.

6. The method of claim 2, wherein calculating the transport delay value comprises:

establishing a turn-around delay known to the one node;

determining the round trip delay between the one node and the adjacent node;

subtract the turn-around delay from the round trip delay to produce a corrected round trip delay; and

divide the corrected round trip delay by two.

7. The method of claim 1, wherein passing the generated signal path delay values comprise passing the generated signal path delay values using a delay management channel.

8. The method of claim 1, wherein passing the generated signal path delay values comprises passing the generated signal path delay values using a delay management channel with an optional framing bit and a plurality of data bits.

9. The method of claim 8, wherein passing the generated signal path delay values comprises segmenting the signal path delay value over the delay management channel using the optional framing bit.

10. The method of claim 1, wherein generating the signal path delay value comprises adding an intrinsic delay value for the node generating the signal path delay value.

11. The method of claim 1, further comprising setting a delay for each of the plurality of nodes based on the signal path delay value.

12. A method for programming the delay for a node in a communication system, the method comprising:

receiving a selected delay value for the node;

receiving a signal path delay value at the node indicating a delay for signals communicated to the node, the signal path delay comprising an aggregation of transport delays calculated by each node for segments of the communication system between the node and a host node; and

calculating an additional delay necessary to meet the selected delay value.

13. The method of claim 12, wherein calculating the additional delay comprises subtracting the signal path delay from the selected delay.

14. The method of claim 12, wherein calculating the additional delay comprises calculating forward and reverse path delays.

15. The method of claim 12, wherein calculating the additional delay comprises subtracting the signal path delay and an intrinsic delay for the node from the selected delay.

16. A communications network, the network comprising:

a host node including a host node processor;

a plurality of remote nodes in communication with the host node, the plurality of remote nodes each including a remote node processor;

wherein the host processor comprises program instructions that;

discover a transport delay for each of the plurality of remote nodes that is adjacent to the host node, and

calculate a signal path delay value for each adjacent node based on the transport path delay discovered for the adjacent node; and

wherein each of the remote node processors comprises program instructions that;

discover a transport delay for each of the plurality of remote nodes that are adjacent to the remote node, and

calculate a signal path delay value based on the transport delay discovered for the adjacent nodes and a received signal path delay value.

17. The communication network of claim 16, wherein the host processor discovers the transport delay by pinging the remote nodes that are adjacent to the host node.

18. The communication network of claim 16, wherein the host node and the plurality of remote nodes are coupled by at least one of optical fiber, free space optics, coaxial cable, twisted pair, and millimeter wave wireless links.

19. The communication network of claim 16, wherein the remote node processors further use an intrinsic processing delay to calculate the signal path delay value.

20. The communication network of claim 16, wherein the remote node processor further includes program instructions that establish a selected delay for the remote node based on a selected delay and the received signal path delay value for the remote node.

21. The communication network of claim 16, wherein the plurality of remote nodes are communicatively coupled to the host node in at least one of a tree and branch network configuration, a hub and spoke network configuration, and a common bus configuration.

22. The communication network of claim 16, wherein each of the remote nodes comprise a remote antenna unit.

23. A program product comprising program instructions, embodied on a storage medium, the program instructions cause at least one programmable processor in a node within a distributed communications network to:

discover a transport delay between the node and at least one adjacent node within the network;

calculate a signal path delay value for the adjacent node based on the transport delay discovered; and

propagate a signal based on the generated signal path delay value to at least one additional level of nodes in the network, if any, until all of the nodes within the network have respective signal path delay values.