Packet transmission via multiple links in a wireless communication system

• US 8,483,223 B2
• Filed: 05/02/2008
• Issued: 07/09/2013
• Est. Priority Date: 02/01/2008
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Black, Peter John, Rezaiifar, Ramin
• Primary Examiner(s): Shah, Chirag
• Assistant Examiner(s): PERSAUD, AMARNAUTH G
• Application Number:
  US12/114,427
• Publication Number:
  US 20090196294A1
• Time in Patent Office: 1,894 Days
• Field of Search: None
• US Class Current: 370/394
• CPC Class Codes: H04L 1/0001 Systems modifying transmission characteristics according to link quality, e.g. power backoff adaptive data allocation for multicarrier modulation H04L5/0044; controlling transmission power for radio systems H04W52/04
• CPC Class Codes: H04L 1/1607 Details of the supervisory signal
• CPC Class Codes: H04L 1/1812 Hybrid protocols; Hybrid automatic repeat request [HARQ]
• CPC Class Codes: H04L 1/1854 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 1/1874 Buffer management
• CPC Class Codes: H04L 1/1887 Scheduling and prioritising arrangements
• CPC Class Codes: H04L 2001/0096 Channel splitting in point-to-point links
• CPC Class Codes: H04L 25/14 Channel dividing arrangements , i.e. in which a single bit stream is divided between several baseband channels and reassembled at the receiver
• CPC Class Codes: H04L 47/10 Flow control; Congestion control
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0053 Allocation of signaling, i.e. of overhead other than pilot signals

Abstract

Techniques for generating and transmitting packets on multiple links in a wireless communication system are described. In one aspect, a transmitter generates new packets for the multiple links based on the likelihood of each link being available. The transmitter determines the likelihood of each carrier being available based on whether or not there is a pending packet on that carrier and, if yes, the number of subpackets sent for the pending packet. The transmitter generates new packets such that packets for links progressively less likely to be available contain data units with progressively higher sequence numbers. The transmitter determines whether each link is available and sends a packet on each link that is available. In another aspect, the transmitter generates and sends new packets in a manner to ensure in-order transmission. In one design, the transmitter generates new packets for each possible combination of links that might be available.

Claims

1. A method of transmitting data in a wireless communication system, comprising:

obtaining a plurality of data units to send, each data unit being associated with a sequence number indicative of a position of the data unit among the plurality of data units;

determining likelihood of each of multiple links being available for sending data; and

generating multiple packets for the multiple links based on the likelihood of each link being available, the multiple packets comprising a first packet for a first link most likely to be available and a last packet for a last link least likely to be available, the first packet comprising a data unit having a lowest sequence number and the last packet comprising a data unit having a highest sequence number among all data units in the multiple packets;

wherein the determining the likelihood of each of the multiple links being available comprises determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet.

2. The method of claim 1, wherein the determining the likelihood of each of the multiple links being available comprises determining that a link will be available if there is no pending packet on the link or if a maximum number of subpackets has been sent for a pending packet on the link.

3. The method of claim 1, wherein the generating the multiple packets for the multiple links comprises generating one packet for each of the multiple links, with packets for links progressively less likely to be available comprising data units with progressively higher sequence numbers.

4. The method of claim 3, wherein the generating the multiple packets for the multiple links further comprises generating an additional packet for a second link second most likely to be available, the additional packet comprising the data unit having the lowest sequence number and being sent on the second link only if the first link is unavailable.

5. The method of claim 1, further comprising:

determining whether each of the multiple links is available; and

sending each of the multiple packets on a respective one of the multiple links if the link is available.

6. The method of claim 1, further comprising:

determining whether each of the multiple links is available; and

sending each of the multiple packets on a respective one of the multiple links if the link is available and if all links more likely to be available are also available.

7. The method of claim 1, further comprising:

returning data units in each packet not sent on an unavailable link to a queue for transmission in a subsequent time interval.

8. The method of claim 1, wherein the multiple links correspond to multiple carriers, one link for each carrier.

9. The method of claim 1, further comprising:

assigning a sequence number to each data unit.

10. The method of claim 9, wherein the data units are assigned sequentially increasing sequence numbers.

11. The method of claim 9, wherein the earliest data unit in a data queue is assigned a lowest sequence number.

12. The method of claim 9, wherein the sequence number is assigned by Radio Link Protocol.

13. The method of claim 1, wherein the data units with a lowest sequence number are provided to a new packet for a carrier with the highest priority.

14. An apparatus for transmitting data in a wireless communication system, comprising:

means for obtaining a plurality of data units to send, each data unit being associated with a sequence number indicative of a position of the data unit among the plurality of data units;

means for determining likelihood of each of multiple links being available for sending data; and

means for generating multiple packets for the multiple links based on the likelihood of each link being available, the multiple packets comprising a first packet for a first link most likely to be available and a last packet for a last link least likely to be available, the first packet comprising a data unit having a lowest sequence number and the last packet comprising a data unit having a highest sequence number among all data units in the multiple packets;

wherein the determining the likelihood of each of the multiple links being available comprises determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet.

15. The apparatus of claim 14, wherein the means for determining the likelihood of each of the multiple links being available comprises

means for determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet, and

means for determining that a link will be available if there is no pending packet on the link or if a maximum number of subpackets has been sent for a pending packet on the link.

16. The apparatus of claim 14, wherein the means for generating the multiple packets for the multiple links comprises means for generating one packet for each of the multiple links, with packets for links progressively less likely to be available comprising data units with progressively higher sequence numbers.

17. The apparatus of claim 14, further comprising:

means for determining whether each of the multiple links is available; and

means for sending each of the multiple packets on a respective one of the multiple links if the link is available.

18. An apparatus for a wireless communication system, comprising:

at least one processor configured to obtain a plurality of data units to send, each data unit being associated with a sequence number indicative of a position of the data unit among the plurality of data units, to determine likelihood of each of multiple links being available for sending data, and to generate multiple packets for the multiple links based on the likelihood of each link being available, the multiple packets comprising a first packet for a first link most likely to be available and a last packet for a last link least likely to be available, the first packet comprising a data unit having a lowest sequence number and the last packet comprising a data unit having a highest sequence number among all data units in the multiple packets; and

memory coupled to the processor,

wherein the determining the likelihood of each of the multiple links being available comprises determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet.

19. The apparatus of claim 18, wherein the at least one processor is configured to determine the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet, and to determine that a link will be available if there is no pending packet on the link or if a maximum number of subpackets has been sent for a pending packet on the link.

20. The apparatus of claim 18, wherein the at least one processor is configured to generate one packet for each of the multiple links, with packets for links progressively less likely to be available comprising data units with progressively higher sequence numbers.

21. The apparatus of claim 18, wherein the at least one processor is configured to determine whether each of the multiple links is available, and to send each of the multiple packets on a respective one of the multiple links if the link is available.

22. A non-transitory computer-readable medium comprising instructions for causing a processor to perform a method, the method comprising:

obtaining a plurality of data units to send, each data unit being associated with a sequence number indicative of a position of the data unit among the plurality of data units,

determining likelihood of each of multiple links being available for sending data; and

generating multiple packets for the multiple links based on the likelihood of each link being available, the multiple packets comprising a first packet for a first link most likely to be available and a last packet for a last link least likely to be available, the first packet comprising a data unit having a lowest sequence number and the last packet comprising a data unit having a highest sequence number among all data units in the multiple packets;

wherein the determining the likelihood of each of the multiple links being available comprises determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet.

23. The non-transitory computer-readable medium of claim 22, wherein the method further comprises:

determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet; and

determining that a link will be available if there is no pending packet on the link or if a maximum number of subpackets has been sent for a pending packet on the link.

24. The non-transitory computer-readable medium of claim 22, wherein the method further comprises:

generating one packet for each of the multiple links, with packets for links progressively less likely to be available comprising data units with progressively higher sequence numbers.

25. The non-transitory computer-readable medium of claim 22, wherein the method further comprises:

determining whether each of the multiple links is available; and

sending each of the multiple packets on a respective one of the multiple links if the link is available.

26. A method of transmitting data in a wireless communication system, comprising:

obtaining a plurality of data units to send, each data unit being associated with a sequence number indicative of a position of the data unit among the plurality of data units;

generating multiple packets for multiple links, each packet comprising at least one data unit among the plurality of data units;

determining whether each of the multiple links is available; and

sending at least one packet among the multiple packets on at least one available link among the multiple links, the at least one packet comprising data units with sequence numbers lower than sequence numbers of unsent data units, if any, in the multiple packets;

wherein the multiple links comprise first and second links, and wherein the generating the multiple packets for the multiple links comprises generating a first packet comprising a data unit with a lowest sequence number for the first link, generating a second packet comprising a data unit with a higher sequence number for the second link, and generating a third packet comprising the data unit with the lowest sequence number for the second link;

wherein the sending the at least one packet comprises sending the first packet on the first link and the second packet on the second link if the first and second links are both available, sending only the first packet on the first link if only the first link is available, and sending only the third packet on the second link if only the second link is available.

27. The method of claim 26, wherein the generating the multiple packets for the multiple links comprises generating packets for all possible combinations of available links among the multiple links.

28. The method of claim 26, wherein the generating the multiple packets for the multiple links comprises generating the multiple packets such that one packet can be sent on each available link and data units in sent packets have sequence numbers lower than sequence numbers of any unsent data units.

29. The method of claim 26, wherein the generating the multiple packets for the multiple links comprises generating at least two packets comprising different data units for each of at least one link among the multiple links.

30. The method of claim 26, wherein the multiple links comprise three links, wherein the generating the multiple packets for the multiple links comprises generating up to seven packets for the three links, and wherein the sending the at least one packet comprises sending up to three packets on up to three available links, the up to three packets comprising data units with lower sequence numbers than sequence numbers of unsent data units, if any, in the up to seven packets.

31. A method of receiving data in a wireless communication system, comprising:

receiving multiple packets from multiple links, each packet comprising at least one data unit, each data unit being associated with a sequence number indicative of a position of the data unit among a plurality of data units, the multiple packets being generated by a transmitter based on likelihood of each of the multiple links being available for sending data, the multiple packets comprising a first packet for a first link most likely to be available and a last packet for a last link least likely to be available, the first packet comprising a data unit having a lowest sequence number and the last packet comprising a data unit having a highest sequence number among all data units in the multiple packets; and

decoding the multiple packets to obtain decoded packets;

wherein the determining the likelihood of each of the multiple links being available comprises determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet.

32. The method of claim 31, further comprising:

detecting a hole due to successful decoding of a packet comprising a data unit with a sequence number higher than sequence numbers of missing data units not yet decoded; and

delaying transmission of a negative acknowledgement (NAK) for the detected hole for a predetermined amount of time to allow for transmission and decoding of at least one packet comprising the missing data units.

33. The method of claim 32, wherein transmission of the at least one packet comprising the missing data units starts at same time or earlier than the packet successfully decoded, and wherein the delaying transmission of the NAK for the detected hole comprises delaying transmission of the NAK until a maximum transmission time for the at least one packet has elapsed.

34. The method of claim 32, wherein transmission of the at least one packet comprising the missing data units starts later than the packet successfully decoded, and wherein the delaying transmission of the NAK for the detected hole comprises delaying transmission of the NAK until an expected maximum transmission time for the at least one packet has elapsed.

35. The method of claim 34, further comprising:

determining the expected maximum transmission time for the at least one packet based on the at least one packet being sent at next transmission opportunity and a maximum transmission time for the at least one packet.

36. An apparatus for receiving data in a wireless communication system, comprising:

means for receiving multiple packets from multiple links, each packet comprising at least one data unit, each data unit being associated with a sequence number indicative of a position of the data unit among a plurality of data units, the multiple packets being generated by a transmitter based on likelihood of each of the multiple links being available for sending data, the multiple packets comprising a first packet for a first link most likely to be available and a last packet for a last link least likely to be available, the first packet comprising a data unit having a lowest sequence number and the last packet comprising a data unit having a highest sequence number among all data units in the multiple packets; and

means for decoding the multiple packets to obtain decoded packets;

wherein the determining the likelihood of each of the multiple links being available comprises determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet.

37. The apparatus of claim 36, further comprising:

means for detecting a hole due to successful decoding of a packet comprising a data unit with a sequence number higher than sequence numbers of missing data units not yet decoded; and

means for delaying transmission of a negative acknowledgement (NAK) for the detected hole for a predetermined amount of time to allow for transmission and decoding of at least one packet comprising the missing data units.

38. The apparatus of claim 37, wherein transmission of the at least one packet comprising the missing data units starts at same time or earlier than the packet successfully decoded, and wherein the means for delaying transmission of the NAK for the detected hole comprises means for delaying transmission of the NAK until a maximum transmission time for the at least one packet has elapsed.

39. The apparatus of claim 37, wherein transmission of the at least one packet comprising the missing data units starts later than the packet successfully decoded, and wherein the means for delaying transmission of the NAK for the detected hole comprises means for delaying transmission of the NAK until an expected maximum transmission time for the at least one packet has elapsed.

40. An apparatus for receiving data in a wireless communication system, comprising:

At least one processor configured to receive multiple packets from multiple links, each packet comprising at least one data unit, each data unit being associated with a sequence number indicative of a position of the data unit among a plurality of data units, the multiple packets being generated by a transmitter based on likelihood of each of the multiple links being available for sending data, the multiple packets comprising a first packet for a first link most likely to be available and a last packet for a last link least likely to be available, the first packet comprising a data unit having a lowest sequence number and the last packet comprising a data unit having a highest sequence number among all data units in the multiple packets, and to decode the multiple packets to obtain decoded packets; and

memory coupled to the processor;

wherein the determining the likelihood of each of the multiple links being available comprises determining the likelihood of each link with a pending packet being available based on number of subpackets sent for the pending packet.

41. The apparatus of claim 40, wherein the at least one processor is configured to detect a hole due to successful decoding of a packet comprising a data unit with a sequence number higher than sequence numbers of missing data units not yet decoded, and to delay transmission of negative acknowledgement (NAK) for the detected hole for a predetermined amount of time to allow for transmission and decoding of at least one packet comprising the missing data units.

42. The apparatus of claim 41, wherein transmission of the at least one packet comprising the missing data units starts at same time or earlier than the packet successfully decoded, and wherein at least one processor is configured to delay transmission of the NAK until a maximum transmission time for the at least one packet has elapsed.

43. The apparatus of claim 41, wherein transmission of the at least one packet comprising the missing data units starts later than the packet successfully decoded, and wherein at least one processor is configured to delay transmission of the NAK until an expected maximum transmission time for the at least one packet has elapsed.