Interference detection and avoidance in a telecommunication network

Patent metadata

Field	Value
Publication number	US-9503180-B2
Application number	US-201414476969-A
Country	US
Kind code	B2
Filing date	Sep 4, 2014
Priority date	Sep 4, 2014
Publication date	Nov 22, 2016
Grant date	Nov 22, 2016

Abstract

Presented herein are techniques for detection and avoidance of interference in a telecommunications network. In one example, a cable modem termination system (CMTS) is configured to receive upstream traffic from a plurality of cable modems. The CMTS detects collision characteristics resulting from substantially simultaneous transmissions from different combinations of the cable modems. Based on the detected collision characteristics, the CMTS designates/identifies collision groups for each of a plurality of the cable modems. After designation of the collision groups, the CMTS schedules upstream transmissions by the plurality of cable modems such that cable modems within the same collision group do not transmit within a same time frame and such that two or more cable modems that are not within the same collision group may transmit within a same time frame.

First claim

What is claimed is:

1. A method comprising:
at a cable modem termination system:
detecting collision characteristics resulting from substantially simultaneous upstream transmissions from different combinations of cable modems;
in response to detecting the collision characteristics, dynamically designating collision groups for each of a plurality of the cable modems, wherein a collision group comprises a primary cable modem and one or more secondary cable modems that, based on the collision characteristics, represent each of the cable modems that may interfere with the upstream transmissions of the primary cable modem; and
scheduling upstream transmissions by the plurality of cable modems such that the primary cable modem and the one or more secondary cable modems within the same collision group do not transmit within a same time frame and such that two or more cable modems that are not within the same collision group may transmit within a same time frame.

2. The method of claim 1 , wherein detecting collision characteristics comprises:
scheduling sets of the cable modems to transmit traffic to the cable modem termination system, wherein the cable modems within each set transmit substantially simultaneously to the cable modem termination system, but the transmissions from the different sets occur sequentially; and
analyzing one or more metrics associated with receipt of the transmissions from each set to detect collision characteristics.

3. The method of claim 2 , wherein the cable modems within each set transmit within the same time frame and on the same frequency channel.

4. The method of claim 2 , wherein the cable modems within each set transmit within the same time frame and on different frequency channels.

5. The method of claim 2 , wherein analyzing one or more metrics associated with receipt of the transmissions from each set to detect collision characteristics comprises:
analyzing physical layer (PHY) metrics associated with receipt of the transmissions from each set of cable modems to detect collision characteristics.

6. The method of claim 2 , wherein analyzing one or more metrics associated with receipt of the transmissions from each set to detect collision characteristics comprises:
analyzing media access control (MAC) layer metrics associated with receipt of the transmissions from each set of cable modems to detect collision characteristics.

7. The method of claim 1 , further comprising:
scheduling voice services to cable modems within the same collision group in different time frames.

8. A cable modem termination system apparatus comprising:
one or more interfaces to receive, via telecommunications network, upstream traffic from cable modems;
one or more processors that:
detect collision characteristics resulting from substantially simultaneous upstream transmissions from different combinations of the cable modems;
in response to detecting the collision characteristics, dynamically identify collision groups for each of a plurality of the cable modems, wherein a collision group comprises a primary cable modem and one or more secondary cable modems that, based on the collision characteristics, represent each of the cable modems that may interfere with the upstream transmissions of the primary cable modem; and
schedule upstream transmissions by the plurality of cable modems such that the primary cable modem and the one or more secondary cable modems within the same collision group do not transmit within a same time frame and such that two or more cable modems that are not within the same collision group may transmit within a same time frame.

9. The apparatus of claim 8 , wherein the one or more processors:
schedule sets of the cable modems to transmit traffic to the cable modem termination system, wherein the cable modems within each set transmit substantially simultaneously to the cable modem termination system, but the transmissions from the different sets occur sequentially; and
analyze one or more metrics associated with receipt of the transmissions from each set of cable modems to detect collision characteristics.

10. The apparatus of claim 9 , wherein to analyze one or more metrics associated with receipt of the transmissions from each set of cable modems to detect collision characteristics, the one or more processors:
analyze physical layer (PHY) metrics associated with receipt of the transmissions from each set to detect collision characteristics.

11. The apparatus of claim 9 , wherein to analyze one or more metrics associated with receipt of the transmissions from each set of cable modems to detect collision characteristics, the one or more processors:
analyze media access control (MAC) layer metrics associated with receipt of the transmissions from each set to detect collision characteristics.

12. The apparatus of claim 8 , wherein the one or more processors:
schedule voice services to cable modems within the same collision group in different time frames.

13. The apparatus of claim 8 , wherein the one or more processors comprise a collision detection processor, a grouping processor, and a scheduling processor, and are each different processing entities.

14. The apparatus of claim 8 , wherein one or more processors comprise a collision detection processor, a grouping processor, and a scheduling processor of which two or more are the same processing entities.

15. The apparatus of claim 8 , further comprising a physical layer (PHY) processing unit and a media access control (MAC) processing unit, wherein the at least one of the one or more processors is a collision detection processor that is part of the PHY processing unit and wherein the PHY processing unit exports collision information to the MAC processing unit.

16. A method comprising:
at a cable modem termination system:
scheduling a plurality of sets of cable modems to transmit upstream traffic on a shared frequency channel, wherein the cable modems within each of the plurality of sets transmit substantially simultaneously on the frequency channel, but the transmissions from the different sets occur sequentially on the frequency channel;
detecting optical beat interference (OBI) resulting from the substantially simultaneous upstream transmissions within one or more of the plurality of sets;
in response to detecting the OBI resulting from the substantially simultaneous upstream transmissions, dynamically identifying collision groups for each of a plurality of the cable modems, wherein a collision group comprises a primary cable modem and one or more secondary cable modems that, based on the detected OBI, represent each of the cable modems that may interfere with the upstream transmissions of the primary cable modem; and
scheduling upstream transmissions by the plurality of cable modems such that cable modems within the same collision group do not transmit within a same time frame and such that two or more cable modems that are not within the same collision group may transmit within a same time frame.

17. The method of claim 16 , wherein detecting OBI comprises:
analyzing one or more metrics associated with receipt of the transmissions from each set of cable modems to detect collision characteristics.

18. The method of claim 17 , wherein analyzing one or more metrics associated with receipt of the transmissions from each set to detect collision characteristics comprises:
analyzing physical layer (PHY) metrics associated with receipt of the transmissions from each set of cable modems to detect collision characteristics.

19. The

Assignees

• Cisco Tech Inc

Inventors

• Jin Hang
• Liu Tong
• Sowinski Pawel
• Li De Fu
• Skrobko John

Classifications

• H04B10/0795 Primary

  Performance monitoring; Measurement of transmission parameters · CPC title

• H04B10/0793

  Network aspects, e.g. central monitoring of transmission parameters · CPC title

• H04L43/0882

  Utilisation of link capacity · CPC title

• H04J3/1694

  Allocation of channels in TDM/TDMA networks, e.g. distributed multiplexers (Passive Optical Networks H04Q11/0062) · CPC title

• H04L12/2801 Primary

  Broadband local area networks · CPC title