Mitigation of traffic congestion in dual connectivity systems

• US 9,560,684 B2
• Filed: 06/27/2014
• Issued: 01/31/2017
• Est. Priority Date: 09/26/2013
• Status: Active Grant

• Current Assignee: Intel Corporation
• Original Assignee: Intel IP Corporation (Intel Corporation)
• Inventors: Sivanesan, Kathiravetpillai, Koc, Ali, Vannithamby, Rath
• Primary Examiner(s): Smarth, Gerald
• Application Number:
  US14/317,900
• Publication Number:
  US 20150085667A1
• Time in Patent Office: 949 Days
• US Class Current: 1/1
• CPC Class Codes: G06F 9/4856 resumption being on a different machine, e.g. task migration, virtual machine migration G06F9/5088 takes precedence
• CPC Class Codes: H04L 1/12 by using return channel
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 47/12 Avoiding congestion; Recovering from congestion
• CPC Class Codes: H04L 47/122 by diverting traffic away from congested entities
• CPC Class Codes: H04L 5/001 the frequencies being arranged in component carriers
• CPC Class Codes: H04L 5/0035 Resource allocation in a cooperative multipoint environment
• CPC Class Codes: H04L 5/0037 Inter-user or inter-terminal allocation
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0055 Physical resource allocation for ACK/NACK for physical mapping arrangements in ARQ protocols H04L1/1861
• CPC Class Codes: H04L 67/025 for remote control or remote monitoring of applications
• CPC Class Codes: H04L 67/104 Peer-to-peer [P2P] networks
• CPC Class Codes: H04W 24/04 Arrangements for maintaining operational condition
• CPC Class Codes: H04W 24/10 Scheduling measurement reports ; Arrangements for measurement reports
• CPC Class Codes: H04W 28/02 Traffic management, e.g. flow control or congestion control
• CPC Class Codes: H04W 36/03 Reselecting a link using a direct mode connection
• CPC Class Codes: H04W 36/32 by location or mobility data, e.g. speed data
• CPC Class Codes: H04W 40/22 using selective relaying for reaching a BTS [Base Transceiver Station] or an access point
• CPC Class Codes: H04W 40/24 : Connectivity information management, e.g. connectivity discovery or connectivity update
• CPC Class Codes: H04W 48/16 : Discovering, processing access restriction or access information
• CPC Class Codes: H04W 52/0274 : by switching on or off the equipment or parts thereof
• CPC Class Codes: H04W 72/0446 : Resources in time domain, e.g. slots or frames
• CPC Class Codes: H04W 72/0453 : Resources in frequency domain, e.g. a carrier in FDMA
• CPC Class Codes: H04W 72/23 : in the downlink direction of a wireless link, i.e. towards a terminal
• CPC Class Codes: H04W 76/14 : Direct-mode setup
• CPC Class Codes: H04W 76/18 : Management of setup rejection or failure
• CPC Class Codes: H04W 76/27 : Transitions between radio resource control [RRC] states
• CPC Class Codes: H04W 76/38 : triggered by timers
• CPC Class Codes: H04W 8/005 : Discovery of network devices, e.g. terminals
• CPC Class Codes: H04W 84/12 : WLAN [Wireless Local Area Networks]
• CPC Class Codes: H04W 88/08 : Access point devices
• CPC Class Codes: H04W 92/20 : between access points
• CPC Class Codes: Y02D 10/00 : Energy efficient computing, e.g. low power processors, power management or thermal management
• CPC Class Codes: Y02D 30/70 : in wireless communication networks

Abstract

Technology for mitigating traffic congestion is disclosed. A master evolved node B (MeNB) can identify service data unit (SDU) packets that are dropped in a retransmission buffer of a packet data convergence protocol (PDCP) layer of the MeNB. The MeNB can create a list of packet data unit (PDU) packets that are dropped at the PDCP layer of the MeNB, wherein the PDU packets that are dropped are associated with the SDU packets. The MeNB can send the list of dropped PDU packets, from the PDCP layer of the MeNB to the PDCP layer of a user equipment (UE), to enable the UE to distinguish between delayed PDU packets and the dropped PDU packets.

Claims

1. A master evolved node B (MeNB) operable to mitigate traffic congestion, the MeNB having computer circuitry configured to:

identify service data unit (SDU) packets that are dropped in a retransmission buffer of a packet data convergence protocol (PDCP) layer of the MeNB;

create a list of packet data unit (PDU) packets that are dropped at the PDCP layer of the MeNB, wherein the PDU packets that are dropped are associated with the SDU packets; and

send the list of dropped PDU packets, from the PDCP layer of the MeNB to the PDCP layer of a user equipment (UE), to enable the UE to distinguish between delayed PDU packets and the dropped PDU packets.

2. The computer circuitry of claim 1, wherein dropping the PDU packets indicates an overflow buffer status to an internet protocol (IP) layer, wherein the IP layer reduces a packet rate to the PDCP layer at the MeNB in response to the overflow buffer status.

3. The computer circuitry of claim 1, wherein the PDU packets are dropped in response to detecting a potential overflow at a retransmission buffer of the MeNB.

4. The computer circuitry of claim 3, wherein the potential overflow is due to delay or capacity constraints on at least one of:

an X2 link between the MeNB and a secondary evolved node B (SeNB), a radio link between the MeNB and the UE, or a radio link between the SeNB and the UE.

5. The computer circuitry of claim 3, further configured to recalculate a downlink (DL) split ratio when the potential overflow occurs at the retransmission buffer, the DL split ratio defining a first percentage of PDU packets to be transmitted to the UE via the SeNB and a second percentage of PDU packets to be transmitted directly to the UE.

6. The computer circuitry of claim 1, further configured to:

detect a potential overflow at a retransmission buffer of the MeNB, wherein SDU packets are stored in the retransmission buffer for retransmission in downlink to one of the UE or a secondary evolved node B (SeNB);

detect a type of traffic associated with the SDU packets; and

extend a discard counter at the retransmission buffer based in part on the type of traffic associated with the SDU packets in order to avoid premature flushing of the SDU packets at the retransmission buffer.

7. The computer circuitry of claim 6, further configured to extend the discard counter at the retransmission buffer when the type of traffic associated with the SDU packets is delay-tolerant traffic.

8. The computer circuitry of claim 6, further configured to not extend the discard counter at the retransmission buffer when the type of traffic associated with the SDU packets is delay-sensitive traffic.

9. The computer circuitry of claim 6, wherein extending the discard counter at the retransmission buffer includes increasing a length of a packet data convergence protocol sequence number (PDCP SN) to include multiple least significant bits.

10. The computer circuitry of claim 1, further configured to communicate with a secondary evolved node B (SeNB) via an X2 link in a dual connectivity architecture.

11. A method for mitigating traffic congestion, the method comprising:

detecting a potential overflow at a retransmission buffer of a packet data convergence protocol (PDCP) layer of a user equipment (UE), wherein packet data unit (PDU packets) are stored in the retransmission buffer for retransmission in downlink to one of a master evolved node B (MeNB) or a secondary evolved node B (SeNB);

detecting a type of traffic associated with the PDU packets; and

extending a discard counter at the retransmission buffer based in part on the type of traffic associated with the PDU packets in order to avoid premature flushing of the PDU packets at the retransmission buffer.

12. The method of claim 11, further comprising extending the discard counter at the retransmission buffer when the type of traffic associated with the PDU packets is delay-tolerant traffic.

13. The method of claim 11, further comprising determining to not extend the discard counter at the retransmission buffer when the type of traffic associated with the PDU packets is delay-sensitive traffic.

14. The method of claim 11, further comprising:

identifying service data unit (SDU) packets that are dropped in the retransmission buffer of the PDCP layer of the UE, wherein the SDU packets are dropped in response to detecting the potential overflow at the retransmission buffer;

creating a list of packet data unit (PDU) packets that are dropped at the PDCP layer of the UE, wherein the PDU packets that are dropped are associated with the SDU packets; and

sending the list of dropped PDU packets, from the PDCP layer of the UE to the PDCP layer of the MeNB to enable the MeNB to distinguish between delayed PDU packets and the dropped PDU packets.

15. The method of claim 14, wherein the PDU packets are dropped to indicate an overflow buffer status to an internet protocol (IP) layer to reduce a packet rate to the PDCP layer at the UE.

16. The method claim 14, further comprising dropping the PDU packets due to delay or capacity constraints of at least one of:

an X2 link between the MeNB and the SeNB, a radio link between the MeNB and the UE, or a radio link between the SeNB and the UE.

17. The method of claim 14, further comprising dropping the PDU packets to indicate a buffer status to an internet protocol (IP) layer, wherein the IP layer reduces a packet rate to the PDCP layer at the UE in response to the overflow buffer status.

18. The method of claim 11, further comprising requesting a modified uplink (UL) split ratio from the MeNB when the potential overflow occurs at the retransmission buffer of the UE.

19. The method of claim 11, wherein the UE includes an antenna, a touch sensitive display screen, a speaker, a microphone, a graphics processor, an application processor, an internal memory, or a non-volatile memory port.

20. A master evolved node B (MeNB) operable to mitigate traffic congestion, the MeNB having computer circuitry configured to:

determine that a retransmission buffer at the MeNB is storing a number of packets that exceed a selected threshold level;

adjust a downlink (DL) split ratio for the packets in the retransmission buffer, wherein the packets are to be sent to a secondary evolved node B (SeNB) or directly from the MeNB to a user equipment (UE); and

split a bearer in the PDCP layer of the MeNB based on the adjusted DL split ratio to enable the UE and the SeNB to receive the packets in the retransmission buffer from the MeNB according to the adjusted DL split ratio.

21. The computer circuitry of claim 20, wherein the retransmission buffer is at a packet data convergence protocol (PDCP) layer of the MeNB.

22. The computer circuitry of claim 20, further configured to adjust the DL split ratio for the packets in the retransmission buffer in response to detecting delay or capacity constraints on an X2 link between the MeNB and the SeNB.