RE-USING SEQUENCE NUMBER BY MULTIPLE PROTOCOLS FOR WIRELESS COMMUNICATION

• US 20090003283A1
• Filed: 05/06/2008
• Published: 01/01/2009
• Est. Priority Date: 05/07/2007
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Meylan, Arnaud
• Granted Patent: US 8,331,399 B2
• Time in Patent Office: Days
• US Class Current: 370/331
• CPC Class Codes: H04L 1/008 where the control data relates to payload of a different packet

Abstract

Techniques for re-using sequence number by multiple protocols in a protocol stack are described. In one design, at least one protocol data unit (PDU) from a first protocol may be received as at least one service data unit (SDU) at a second protocol, with each PDU being assigned a different sequence number by the first protocol. A sequence number for each SDU may be determined based on a sequence number for a corresponding PDU from the first protocol. A PDU may be formed by the second protocol based on the at least one SDU. A header may be generated for the PDU and may include (i) the sequence number and possibly a segment offset for the first SDU and (ii) a header block for each remaining SDU, which may include a segment length, a sequence number offset, and a segment offset for that SDU.

Claims

1. A method of processing data for transmission, comprising:

receiving a first sequence number assigned to a first protocol data unit (PDU) by a first protocol; and

using the first sequence number from the first protocol at a second protocol.

2. The method of claim 1, wherein the first protocol is above the second protocol in a protocol stack, the method further comprising:

receiving the first PDU from the first protocol as a service data unit (SDU) at the second protocol;

determining a second sequence number for the SDU based on the first sequence number for the first PDU; and

forming a second PDU at the second protocol based on the SDU.

3. The method of claim 2, further comprising:

addressing data within the SDU based on the second sequence number and an offset from start of the SDU.

4. The method of claim 2, further comprising:

resetting sequence numbering of the second protocol at handover or connection setup;

determining a delta based on a difference between sequence number for the first protocol and sequence number for the second protocol after resetting the sequence numbering; and

determining the second sequence number for the SDU based on the first sequence number for the first PDU and the delta.

5. The method of claim 2, wherein the forming the second PDU comprises

segmenting the SDU to obtain a segment comprising a portion of the SDU,

forming the second PDU comprising the segment, and

generating a header for the second PDU, the header comprising the second sequence number and a segment offset indicating start of the segment within the SDU.

6. The method of claim 5, wherein the segment offset indicates a starting byte in the SDU corresponding to a first byte in the second PDU.

7. The method of claim 1, further comprising:

receiving multiple PDUs from the first protocol as multiple service data units (SDUs) at the second protocol, each of the multiple PDUs being assigned a different sequence number by the first protocol, the multiple PDUs including the first PDU, and the multiple SDUs including a first SDU corresponding to the first PDU; and

forming a second PDU at the second protocol based on the multiple SDUs, the second PDU including the first SDU followed by remaining ones of the multiple SDUs.

8. The method of claim 7, wherein the second PDU comprises all or a portion of the first SDU, all or a portion of a last SDU among the multiple SDUs, and all of each SDU between the first and last SDUs.

9. The method of claim 7, wherein the second PDU comprises all or a portion of each of the multiple SDUs.

10. The method of claim 7, further comprising:

determining a second sequence number for the first SDU based on the first sequence number for the first PDU; and

generating a header for the second PDU, the header comprising the second sequence number for the first SDU and a header block for each remaining one of the multiple SDUs.

11. The method of claim 10, wherein the header further comprises a segment offset indicating a starting byte in the first SDU corresponding to a first byte in the second PDU.

12. The method of claim 10, wherein the header block for each remaining SDU comprises a segment length conveying amount of data from the SDU being sent in the second PDU.

13. The method of claim 10, wherein the header block for each remaining SDU comprises a sequence number offset conveying a difference between a sequence number for the SDU and a sequence number for a preceding SDU in the second PDU.

14. The method of claim 10, wherein the header block for each remaining SDU comprises an extension bit indicating whether or not another header block for another SDU will follow in the header.

15. The method of claim 10, wherein the header block for each remaining SDU comprises a segment offset indicating a starting byte in the SDU being sent in the second PDU.

16. The method of claim 1, wherein the first protocol is below the second protocol in a protocol stack, and wherein the first sequence number is passed from the first protocol up to the second protocol.

17. The method of claim 1, further comprising:

assigning a sequentially increasing sequence number to each PDU generated at the first protocol;

passing a sequence number from the first protocol up to the second protocol for each PDU generated at the second protocol; and

assigning each PDU generated at the second protocol with a sequence number determined based on the sequence number passed up by the first protocol for the PDU.

18. The method of claim 1, wherein the first protocol comprises. Packet Data Convergence Protocol (PDCP) and the second protocol comprises Radio Link Control (RLC).

19. The method of claim 1, wherein the first protocol comprises Radio Link Control (RLC) and the second protocol comprises Packet Data Convergence Protocol (PDCP).

20. An apparatus for wireless communication, comprising:

at least one processor configured to receive a first sequence number assigned to a first protocol data unit (PDU) by a first protocol, and to use the first sequence number from the first protocol at a second protocol.

21. The apparatus of claim 20, wherein the at least one processor is configured to receive the first PDU from the first protocol as a service data unit (SDU) at the second protocol, to determine a second sequence number for the SDU based on the first sequence number for the first PDU, and to form a second PDU at the second protocol based on the SDU.

22. The apparatus of claim 21, wherein the at least one processor is configured to segment the SDU to obtain a segment comprising a portion of the SDU, to form the second PDU comprising the segment, and to generate a header for the second PDU, the header comprising the second sequence number and a segment offset indicating start of the segment within the SDU.

23. The apparatus of claim 20, wherein the at least one processor is configured to receive multiple PDUs from the first protocol as multiple service data units (SDUs) at the second protocol, each of the multiple PDUs being assigned a different sequence number by the first protocol, the multiple PDUs including the first PDU, and the multiple SDUs including a first SDU corresponding to the first PDU, and to form a second PDU at the second protocol based on the multiple SDUs, the second PDU including the first SDU followed by remaining ones of the multiple SDUs.

24. The apparatus of claim 23, wherein the at least one processor is configured to determine a second sequence number for the first SDU based on the first sequence number for the first PDU;

and to generate a header for the second PDU, the header comprising the second sequence number for the first SDU and a header block for each remaining one of the multiple SDUs, the header block for each remaining SDU comprising at least one of a segment length, a sequence number offset, an extension bit, and a segment offset.

25. An apparatus for wireless communication, comprising:

means for receiving a first sequence number assigned to a first protocol data unit (PDU) by a first protocol; and

means for using the first sequence number from the first protocol at a second protocol.

26. The apparatus of claim 25, further comprising:

means for receiving the first PDU from the first protocol as a service data unit (SDU) at the second protocol;

means for determining a second sequence number for the SDU based on the first sequence number for the first PDU; and

means for forming a second PDU at the second protocol based on the SDU.

27. The apparatus of claim 26, wherein the means for forming the second PDU comprises

means for segmenting the SDU to obtain a segment comprising a portion of the SDU,

means for forming the second PDU comprising the segment, and

means for generating a header for the second PDU, the header comprising the second sequence number and a segment offset indicating start of the segment within the SDU.

28. The apparatus of claim 25, further comprising:

means for receiving multiple PDUs from the first protocol as multiple service data units (SDUs) at the second protocol, each of the multiple PDUs being assigned a different sequence number by the first protocol, the multiple PDUs including the first PDU, and the multiple SDUs including a first SDU corresponding to the first PDU; and

means for forming a second PDU at the second protocol based on the multiple SDUs, the second PDU including the first SDU followed by remaining ones of the multiple SDUs.

29. The apparatus of claim 28, further comprising:

means for determining a second sequence number for the first SDU based on the first sequence number for the first PDU; and

means for generating a header for the second PDU, the header comprising the second sequence number for the first SDU and a header block for each remaining one of the multiple SDUs, the header block for each remaining SDU comprising at least one of a segment length, a sequence number offset, an extension bit, and a segment offset.

30. A computer program product, comprising:

a computer-readable medium comprising;

code for causing at least one computer to receive a first sequence number assigned to a first protocol data unit (PDU) by a first protocol; and

code for causing the at least one computer to use the first sequence number from the first protocol at a second protocol.

31. A method of receiving data, comprising:

receiving a first protocol data unit (PDU) at a first protocol;

forming a first service data unit (SDU) at the first protocol based on the first PDU;

determining a first sequence number for the first SDU based on a header for the first PDU;

receiving the first SDU as a second PDU at a second protocol; and

determining a second sequence number for the second PDU based on the first sequence number for the first SDU.

32. The method of claim 31, wherein the determining the second sequence number comprises determining the second sequence number for the second PDU based on the first sequence number for the first SDU and a delta.

33. The method of claim 31, wherein the forming the first SDU comprises

obtaining a segment offset from the header, and

mapping the first PDU to the first SDU starting at a location in the first SDU determined by the segment offset.

34. The method of claim 31, further comprising:

forming multiple SDUs at the first protocol based on the first PDU, the multiple SDUs including the first SDU followed by remaining ones of the multiple SDUs; and

determining a sequence number for each of the multiple SDUs at the first protocol based on the header.

35. The method of claim 34, wherein the determining a sequence number for each of the multiple SDUs at the first protocol comprises

obtaining a sequence number offset for each remaining SDU from the header, and

determining the sequence number for each remaining SDU based on the sequence number offset for the SDU and a sequence number for a preceding SDU.

36. The method of claim 34, further comprising:

obtaining a segment offset for each of the multiple SDUs from the header; and

mapping a portion of data in the first PDU to each of the multiple. SDUs starting at a location in the SDU determined by the segment offset for the SDU.

37. The method of claim 34, further comprising:

obtaining a segment length for each of the multiple SDUs from the header, and

determining an amount of data in the first PDU for each of the multiple SDUs based on the segment length for the PDU.

38. The method of claim 31, wherein the first protocol comprises Radio Link Control (RLC) and the second protocol comprises Packet Data Convergence Protocol (PDCP).

39. An apparatus for wireless communication, comprising:

at least one processor configured to receive a first protocol data unit (PDU) at a first protocol, to form a first service data unit (SDU) at the first protocol based on the first PDU, to determine a first sequence number for the first SDU based on a header for the first PDU, to receive the first SDU as a second PDU at a second protocol, and to determine a second sequence number for the second PDU based on the first sequence number for the first SDU.

40. The apparatus of claim 39, wherein the at least one processor is configured to obtain a segment offset from the header and to map the first PDU to the first SDU starting at a location in the first SDU determined by the segment offset.

41. The apparatus of claim 39, wherein the at least one processor is configured to form multiple SDUs at the first protocol based on the first PDU, the multiple SDUs including the first SDU followed by remaining ones of the multiple SDUs, and to determine a sequence number for each of the multiple SDUs at the first protocol based on the header.

42. The apparatus of claim 41, wherein the at least one processor is configured to obtain at least one of a segment length, a sequence number offset, and a segment offset for each remaining SDU from the header.

43. A method of processing data for transmission, comprising:

receiving multiple service data units (SDUs), each SDU being assigned a respective sequence number;

generating a protocol data unit (PDU) comprising the multiple SDUs; and

generating a header for the PDU, the header comprising a sequence number for a first SDU and a sequence number offset for each remaining SDU in the PDU.

44. The method of claim 43, further comprising:

determining the sequence number offset for each remaining SDU based on a difference between a sequence number for the SDU and a sequence number for a preceding SDU in the PDU.

45. The method of claim 43, wherein the multiple SDUs have non-consecutive sequence numbers.

46. The method of claim 43, wherein the receiving the multiple SDUs comprises receiving the multiple SDUs at Radio Link Control (RLC).

47. An apparatus for wireless communication, comprising:

at least one processor configured to receive multiple service data units (SDUs), each SDU being assigned a respective sequence number, to generate a protocol data unit (PDU) comprising the multiple SDUs, and to generate a header for the PDU, the header comprising a sequence number for a first SDU and a sequence number offset for each remaining SDU in the PDU.

48. The apparatus of claim 47, wherein the at least one:

processor is configured to determine the sequence number offset for each remaining SDU based on a difference between a sequence number for the SDU and a sequence number for a preceding SDU in the PDU.

49. A method of receiving data, comprising:

receiving a protocol data unit (PDU) comprising multiple service data units (SDUs);

receiving a header for the PDU, the header comprising a sequence number for a first SDU and a sequence number offset for each remaining SDU in the PDU; and

determining a sequence number for each of the multiple SDUs based on the sequence number for the first SDU and the sequence number offset for each remaining SDU.

50. The method of claim 49, further comprising:

determining the sequence number for each remaining SDU based on the sequence number offset for the SDU and a sequence number for a preceding SDU in the PDU.

51. The method of claim 49, wherein the multiple SDUs have non-consecutive sequence numbers.

52. An apparatus for wireless communication, comprising:

at least one processor configured to receive a protocol data unit (PDU) comprising multiple service data units (SDUs), to receive a header for the PDU, the header comprising a sequence number for a first SDU and a sequence number offset for each remaining SDU in the PDU, and to determine a sequence number for each of the multiple SDUs based on the sequence number for the first SDU and the sequence number offset for each remaining SDU.

53. The apparatus of claim 52, wherein the at least one processor is configured to determine the sequence number for each remaining SDU based on the sequence number offset for the SDU and a sequence number for a preceding SDU in the PDU.