Method and apparatus for PCDP discard

• US 9,641,655 B2
• Filed: 10/06/2014
• Issued: 05/02/2017
• Est. Priority Date: 10/01/2007
• Status: Active Grant

• Current Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Original Assignee: InterDigital Patent Holdings, Inc. (InterDigital, Inc.)
• Inventors: Sammour, Mohammed, Terry, Stephen E.
• Primary Examiner(s): Ngo, Ricky
• Assistant Examiner(s): NG, CHRISTINE Y
• Application Number:
  US14/507,107
• Publication Number:
  US 20150023370A1
• Time in Patent Office: 939 Days
• Field of Search: 370328, 370338, 370401, 370469
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/188 Time-out mechanisms
• CPC Class Codes: H04L 47/283 in response to processing delays, e.g. caused by jitter or round trip time [RTT]
• CPC Class Codes: H04L 47/32 by discarding or delaying data units, e.g. packets or frames
• CPC Class Codes: H04L 69/04 Protocols for data compression, e.g. ROHC
• CPC Class Codes: H04L 69/28 Timers or timing mechanisms used in protocols
• CPC Class Codes: H04L 69/324 in the data link layer [OSI layer 2], e.g. HDLC
• CPC Class Codes: H04W 28/0205 at the air interface dynamic wireless traffic scheduling H04W72/12
• CPC Class Codes: H04W 80/02 Data link layer protocols

Abstract

A method and apparatus for discarding a packet data convergence protocol (PDCP) service data unit (SDU) are disclosed. A PDCP layer sets a timer and discards a PDCP SDU upon expiration of the timer. The timer may be set upon receiving the PDCP SDU from an upper layer or upon submitting the PDCP SDU to a lower layer for transmission. The timer and a radio link control (RLC) discard timer may be coordinated. Alternatively, the PDCP layer may discard the PDCP SDU based on a notification from an RLC layer or based on a PDCP status report.

Claims

1. A method for discarding one or more of a packet data convergence protocol (PDCP) packet or a radio link control packet, the method comprising:

a PDCP entity receiving a PDCP service data unit (SDU) from upper layers;

the PDCP entity starting a PDCP discard timer upon receiving the PDCP SDU from upper layers;

the PDCP entity processing the PDCP SDU to form a PDCP protocol data unit (PDU);

the PDCP entity sending the PDCP PDU to a radio link control (RLC) entity for transmission;

the PDCP entity discarding the PDCP SDU based on either the PDCP discard timer expiring or receiving a PDCP status report that acknowledges receipt of the PDCP SDU by a receiving PDCP entity; and

the RLC entity discarding an RLC SDU corresponding to the PDCP PDU based on either receiving an indication of PDCP discard from the PDCP entity or re-establishment of RLC.

2. The method as in claim 1, wherein a value for the PDCP discard timer associated with the PDCP SDU is preserved during a PDCP re-establishment procedure.

3. The method as in claim 1, further comprising the RLC entity discarding a RLC PDU corresponding the RLC SDU based on the re-establishment of RLC.

4. The method as in claim 1, further comprising the RLC entity discarding at least one RLC SDU and at least one RLC PDU based on reaching a maximum number of automatic repeat request (ARQ) retransmissions.

5. The method as in claim 1, wherein a threshold value of the PDCP discard timer is configured by a radio resource control layer on a per-radio bearer basis.

6. A wireless transmit receive unit (WTRU) comprising:

a PDCP entity configured to;

receive a PDCP service data unit (SDU) from an upper layer entity,

start a PDCP discard timer upon receiving the PDCP SDU from the upper layer entity,

process the PDCP SDU to form a PDCP protocol data unit (PDU),

send the PDCP PDU to a radio link control (RLC) entity for transmission, and

discard the PDCP SDU based on either the PDCP discard timer expiring or receiving a PDCP status report that acknowledges receipt of the PDCP SDU by a receiving PDCP entity; and

the RLC entity configured to discard an RLC SDU corresponding to the PDCP PDU based on either receiving an indication of PDCP discard from the PDCP entity or re-establishment of RLC.

7. The WTRU as in claim 6, wherein the PDCP entity is further configured to preserve a value for the PDCP discard timer associated with the PDCP SDU during a PDCP re-establishment procedure.

8. The WTRU as in claim 6, wherein the RLC entity is further configured to discard a RLC PDU corresponding the RLC SDU based on the re-establishment of RLC.

9. The WTRU as in claim 6, wherein the RLC entity is further configured to discard at least one RLC SDU and at least one RLC PDU based on reaching a maximum number of automatic repeat request (ARQ) retransmissions.

10. The WTRU as in claim 6, wherein a threshold value of the PDCP discard timer is configured by a radio resource control layer entity on a per-radio bearer basis.