Congestion measurement and reporting for real-time delay-sensitive applications
View Patent ↗Embodiments describe mechanisms for an eNB, possibly assisted by a UE, to detect and possibly alleviate user plane congestion. In some embodiments, the eNB implements UE assisted packet dropping, where the UE requests the eNB drop packets in a sub-QCI that meet designated criteria, such as exceeding a sub-QCI delay threshold. Other embodiments, detect periods of congestion and send congestion indication to the core network when the congestion period exceeds a threshold or when the user experience is degraded. Some embodiments implement both sets of functionality.
1. An enhanced node B (eNB) comprising hardware processing circuitry comprising:
congestion detection processing circuitry configured to:
identify a Quality of Service Class Identifier (QCI) delay for each of a plurality of downlink packets;
determine whether the QCI delay for each of the plurality of downlink packets exceeds a delay threshold;
determine a start of a congestion period responsive to a start criteria;
determine an end of the congestion period responsive to a number of consecutive downlink packets that do not exceed the delay threshold reaching a second count threshold;
determine a length of the congestion period; and
send a congestion indication message to a core network when the length of the congestion period exceeds a first length threshold; and
sub-quality of service class identifier (sub-QCI) packet dropping processing circuitry configured to:
receive, from a user equipment (UE), a first message to initiate sub-QCI packet dropping, the first message comprising a sub-QCI for a QCI;
identify a sub-QCI packet dropping delay threshold for the sub-QCI;
test whether a packet belonging to the sub-QCI exceeds the sub-QCI delay threshold; and
responsive to the packet belonging to the sub-QCI exceeding the delay threshold, make a decision whether to drop the packet belonging to the sub-QCI.
2. The eNB of claim 1 , wherein the start criteria occurs upon a first packet exceeding the delay threshold after at least one packet not exceeding the delay threshold.
3. The eNB of claim 1 , wherein each packet of the plurality of packets is assigned a time stamp when de-queued from a Radio Link Control layer of the eNB and wherein the length of the congestion period is calculated by subtracting the time stamp on a last packet of the congestion period from the time stamp a first packet of the congestion period.
4. The eNB of claim 1 , wherein the congestion detection processing circuitry is further configured to:
establish a window defining a length of time within which downlink packets will be examined;
retrieve a second length threshold; and
send the congestion indication message to the core network responsive to the length of the congestion period exceeding the second length threshold within the window.
5. The eNB of claim 4 , wherein the congestion detection processing circuitry is further configured to:
calculate a packet discard rate within the window;
send the congestion indication message to the core network responsive to the packet discard rate exceeding a discard rate threshold.
6. The eNB of claim 1 , wherein the congestion period is measured on a per-bearer basis.
7. The eNB of claim 1 , wherein the sub-QCI packet dropping processing circuitry is further configured to receive a second message from the UE updating sub-QCI information.
8. The eNB of claim 1 , wherein the first message comprises at least one of:
Internet Protocol (IP) flow classification information;
the sub-QCI packet dropping delay threshold; and
an intra-flow classification parameter.
9. The eNB of claim 1 , wherein the first message comprises a plurality of sub-QCI for the QCI and for each of the plurality of sub-QCI, the first message comprises at least one of:
Internet Protocol (IP) flow classification information;
the sub-QCI packet dropping delay threshold for the sub-QCI; and
an intra-flow classification parameter.
10. The eNB of claim 9 , wherein the plurality of sub-QCI are prioritized and wherein the delay threshold for a higher priority sub-QCI is longer than the delay threshold for a lower priority sub-QCI.
11. An enhanced node B (eNB) comprising:
a processor coupled to a memory
having instructions stored thereon, which when executed cause the processor to:
identify a Quality of Service Class Identifier (QCI) delay for each of a plurality of downlink packets;
establish a window defining a length of time within which downlink packets will be examined;
determine whether the QCI delay for each of the plurality of downlink packets exceeds a delay threshold;
determine a start of a congestion period responsive to a number of consecutive downlink packets that do not exceed the delay threshold reaching a first count threshold followed by a downlink packet that does exceed the delay threshold;
determine an end of the congestion period responsive to a number of consecutive downlink packets that do not exceed the delay threshold reaching a second count threshold;
determine a length of the congestion period;
retrieve a second length threshold;
send a congestion indication message to a core network responsive to the length of the congestion period exceeds a first length threshold; and
send the congestion indication message to the core network responsive to the length of the congestion period exceeding the second length threshold within the window.
12. The eNB of claim 11 , wherein the first count threshold is the same as the second count threshold.
13. The eNB of claim 11 , wherein each packet is assigned a time stamp when de-queued from a Radio Link Control layer of the eNB and wherein the length of the congestion period is calculated by subtracting the time stamp on a last packet of the congestion period from the time stamp a first packet of the congestion period.
14. The eNB of claim 11 , wherein the instructions further cause the processor to:
calculate a packet discard rate within the window;
send the congestion indication message to the core network responsive to the packet discard rate exceeding a discard rate threshold.