FAIR CONGESTION DETECTION FOR TRANSPORT NETWORK LAYER WCDMA COMMUNICATIONS

• US 20110235528A1
• Filed: 03/24/2010
• Published: 09/29/2011
• Est. Priority Date: 03/24/2010
• Status: Active Grant

• Current Assignee: Telefonaktiebolaget LM Ericsson
• Original Assignee: Telefonaktiebolaget LM Ericsson
• Inventors: Rácz, Sándor, Nádas, Szilveszter
• Granted Patent: US 8,493,860 B2
• Time in Patent Office: Days
• US Class Current: 370/244
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/263 Rate modification at the source after receiving feedback
• CPC Class Codes: H04W 24/00 Supervisory, monitoring or testing arrangements
• CPC Class Codes: H04W 28/06 Optimizing the usage of the radio link, e.g. header compression, information sizing , discarding information system modifying transmission characteristic according to link quality by modifying frame length H04L1/0007; dynamic adaptation of the packet size for flow control or congestion control H04L47/365
• CPC Class Codes: H04W 28/10 Flow control between communication endpoints

Abstract

Congestion is detected in a radio access transport network including one or more radio network controllers each coupled to one or more radio base stations. Multiple data packet flows are each associated with a mobile radio terminal communication, and each flow is controlled in the radio access transport network by a corresponding flow control entity. They are monitored for congestion in the transport network. If a congestion area in the transport network is detected for one of the monitored data packet flows, then a determination is made whether other monitored data packet flows share the detected congestion area. Congestion notification information is communicated to the flow control entities corresponding to the other monitored data packet flows that share the detected congestion area. Based on the congestion notification information, the informed flow control entities may take a flow control action, e.g., to enable fair sharing of communications resources in the transport network.

Claims

1. A method for detection and notification of congestion in a radio access transport network including one or more radio network controllers coupled to one or more radio base stations, comprising:

monitoring data packet flows, each data packet flow associated with a mobile radio terminal communication and being controlled in the radio access transport network by a corresponding flow control entity, for congestion in the radio access transport network;

detecting a congestion area in the radio access transport network for one of the monitored data packet flows;

determining whether one or more other monitored data packet flows share the detected congestion area; and

communicating congestion notification information to one or more of the flow control entities corresponding to the one or more other monitored data packet flows that share the detected congestion area so that the informed one or more of the flow control entities may take a flow control action based on the congestion notification information.

2. The method in claim 1, wherein the detected congestion area is a shared congested communications link in the radio access transport network, a shared congested radio network controller, or a shared congested radio base station.

3. The method in claim 1, wherein the monitoring step includes monitoring for packet loss for each of the data packet flows, and the detecting step includes detecting congestion for a data packet flow when a monitored packet loss for that data packet flow exceeds a predetermined value.

4. The method in claim 1, wherein the monitoring step includes monitoring for a packet delay between a radio network controller and a radio base station for each of the data packet flows, and the detecting step includes detecting congestion for a data packet flow when a monitored packet delay for that data packet flow exceeds a predetermined value.

5. The method in claim 4, wherein if a monitored packet delay for that data packet flow exceeds a first predetermined value, then the congestion is detected as soft congestion, and wherein if a monitored packet delay for that data packet flow exceeds a second larger predetermined value, then the congestion is detected as hard congestion.

6. The method in claim 5, wherein the flow control action differs depending on whether the congestion is detected as soft or hard congestion.

7. The method in claim 4, wherein some packets include a reference timer value, the method further comprising detecting reference time values for a packet in different ones of the data packet flows and determining that data packet flows associated with similar detected reference time values correspond to a shared congested communications link in the radio access transport network, a shared congested radio network controller, or a shared congested radio base station.

8. The method in claim 1, further comprising generating a history associated each of the monitored data packet flows including prior congestion notification information communicated for those monitored data packet flows, and determining that one or more data packet flows use a shared congested communications link in the radio access transport network, a shared congested radio network controller, or a shared congested radio base station based on the associated history generated for the one or more data packet flows.

9. The method in claim 1, further comprising determining a current maximum bit rate for each data packet flow allowed in the radio access transport network, and controlling the current maximum bit rate for each data packet flow based on the communicated congestion notification information so that radio access transport network communication resources are shared fairly by the one or more other monitored data packet flows that share the detected congestion area.

10. The method in claim 1, wherein the detected congestion is in a downlink direction from radio network controller to radio base station or in an uplink direction from radio base station to radio network controller.

11. A radio access transport network node for use in a radio access transport network including one or more radio network controllers coupled to one or more radio base stations, comprising electronic circuitry configured to:

monitor data packet flows, each data packet flow associated with a mobile radio terminal communication and being controlled in the radio access transport network by a corresponding flow control entity, for congestion in the radio access transport network;

detect a congestion area in the radio access transport network for one of the monitored data packet flows;

determine whether one or more other monitored data packet flows share the detected congestion area; and

communicate congestion notification information to one or more of the flow control entities corresponding to the one or more other monitored data packet flows that share the detected congestion area so that the informed one or more of the flow control entities may take a flow control action based on the congestion notification information.

12. The radio access transport network node in claim 11, wherein the detected congestion area is a shared congested communications link in the radio access transport network, a shared congested radio network controller, or a shared congested radio base station.

13. The radio access transport network node in claim 11, wherein the electronic circuitry is configured to monitor for packet loss for each of the data packet flows and detect congestion for a data packet flow when a monitored packet loss for that data packet flow exceeds a predetermined value.

14. The radio access transport network node in claim 11, wherein electronic circuitry is configured to monitor for a packet delay between a radio network controller and a radio base station for each of the data packet flows and detect congestion for a data packet flow when a monitored packet delay for that data packet flow exceeds a predetermined value.

15. The radio access transport network node in claim 14, wherein if a monitored packet delay for that data packet flow exceeds a first predetermined value, then the electronic circuitry is configured to detect congestion as soft congestion, and wherein if a monitored packet delay for that data packet flow exceeds a second larger predetermined value, then the electronic circuitry is configured to detect congestion as hard congestion.

16. The radio access transport network node in claim 15, wherein the flow control action differs depending on whether the congestion is detected as soft or hard congestion.

17. The radio access transport network node in claim 14, wherein some packets include a reference timer value, wherein the electronic circuitry is configured to detect reference time values for a packet in different ones of the data packet flows and determine that data packet flows associated with similar detected reference time values correspond to a shared congested communications link in the radio access transport network, a shared congested radio network controller, or a shared congested radio base station.

18. The radio access transport network node in claim 11, wherein the electronic circuitry is configured to generate a history associated each of the monitored data packet flows including prior congestion notification information communicated for those monitored data packet flows, and determining that one or more data packet flows use a shared congested communications link in the radio access transport network, a shared congested radio network controller, or a shared congested radio base station based on the associated history generated for the one or more data packet flows.

19. The radio access transport network node in claim 11, wherein the electronic circuitry is configured to determine a current maximum bit rate for each data packet flow allowed in the radio access transport network, and control the current maximum bit rate for each data packet flow based on the communicated congestion notification information so that radio access transport network communication resources are shared fairly by the one or more other monitored data packet flows that share the detected congestion area.

20. The radio access transport network node in claim 11, wherein the detected congestion is in a downlink direction from radio network controller to radio base station or in an uplink direction from radio base station to radio network controller.

21. The radio access transport network node in claim 11, wherein the radio access transport network node is a radio base station.

22. The radio access transport network node in claim 11, wherein the radio access transport network node is a radio network controller.

23. A radio communications system including a radio access transport network including one or more of the radio access transport network nodes in claim 11 and one or more radio terminals communicating via the radio access transport network.