Transmission structure supporting multi-user scheduling and MIMO transmission

• US 8,638,771 B2
• Filed: 08/10/2006
• Issued: 01/28/2014
• Est. Priority Date: 08/12/2005
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Fernandez-Corbaton, Ivan Jesus, Blanz, Josef J., Granzow, Wolfgang
• Primary Examiner(s): Magloire, Vladimir
• Assistant Examiner(s): Sarwar, Babar
• Application Number:
  US11/502,882
• Publication Number:
  US 20070104150A1
• Time in Patent Office: 2,728 Days
• Field of Search: 370/335, 370/342, 370/320, 370/321, 370/344, 370/478, 370/349, 370/441, 370/479, 370/496, 370/324, 370/350, 370/337, 370/347, 370/442, 370/277, 370/280, 370/328, 370/329, 375/346, 455450-4521, 455/464, 455/68, 455/509, 455/435.3
• US Class Current: 370/345
• CPC Class Codes: H04B 1/7107 Subtractive interference cancellation
• CPC Class Codes: H04B 1/7176 Data mapping, e.g. modulation
• CPC Class Codes: H04B 2201/70703 using multiple or variable rates
• CPC Class Codes: H04B 7/2618 using hybrid code-time division multiple access [CDMA-TDMA]
• CPC Class Codes: H04J 11/003 at the transmitter transmission to multiple receive units in multiple input multiple output [MIMO] H04B7/0452; transmit antenna weighting H04B7/0615
• CPC Class Codes: H04J 13/00 Code division multiplex systems for frequency hopping H04B1/713
• CPC Class Codes: H04J 13/16 Code allocation
• CPC Class Codes: H04L 5/0023 Time-frequency-space
• CPC Class Codes: H04W 72/12 Wireless traffic scheduling

Abstract

Techniques for transmitting data in a manner to support multi-user scheduling, multiple-input multiple-output (MIMO) transmission, and interference cancellation are described. A base station assigns multiple time segments of a transmission time interval (TTI) to at least one terminal, maps data for each terminal to at least one time segment assigned to the terminal, and spreads the data in each time segment with at least one channelization code used in the TTI. A terminal receives an assignment of at least one time segment from among multiple time segments of the TTI, obtains input samples for the at least one time segment, and despreads the input samples with the at least one channelization code used in the TTI.

Claims

1. An apparatus comprising:

at least one processor to assign multiple time segments of a transmission time interval (TTI) comprising a single subframe to a plurality of terminals, to map data for each terminal to at least one time segment assigned to the terminal, to spread data in each of the multiple time segments with at least one channelization code used in the TTI, to map a pilot to at least one time segment designated for pilot transmission, and to spread the pilot with the at least one channelization code used in the TTI, the pilot comprising a predetermined data sequence associated with a base station and known by the plurality of terminals; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the at least one processor assigns each of the multiple time segments to one of the plurality of terminals.

3. The apparatus of claim 1, wherein the at least one processor assigns each terminal with at least one consecutive time segment among the multiple time segments of the TTI.

4. The apparatus of claim 1, wherein the at least one processor assigns the multiple time segments to the plurality of terminals in an order determined by the number of time segments assigned to each terminal.

5. The apparatus of claim 1, wherein the at least one processor assigns the multiple time segments to the plurality of terminals in a sequential order based on the number of time segments assigned to each terminal, with a first terminal with most number of time segments being assigned first in the TTI and a last terminal with least number of time segments being assigned last in the TTI.

6. The apparatus of claim 1, wherein the at least one processor assigns the multiple time segments to the plurality of terminals in a sequential order based on the number of time segments assigned to each terminal, with a first terminal with least number of time segments being assigned first in the TTI and a last terminal with most number of time segments being assigned last in the TTI.

7. The apparatus of claim 1, wherein the at least one processor assigns at least one time segment such that each of the at least one time segment is assigned to one terminal, and assigns at least one other time segment such that each of the at least one other time segment is assigned to at least two terminals.

8. The apparatus of claim 1, wherein the at least one processor assigns at least one time segment such that each time segment is shared by at least two terminals with different channelization codes.

9. The apparatus of claim 1, wherein the at least one processor assigns the multiple time segments to the plurality of terminals for each of multiple streams being sent simultaneously.

10. The apparatus of claim 9, wherein the at least one processor assigns each terminal with at least one time segment across the multiple streams.

11. The apparatus of claim 1, wherein the at least one processor scales the pilot to achieve equal transmit power for the pilot and the data for the plurality of terminals.

12. The apparatus of claim 1, wherein the at least one processor generates signaling for each of the plurality of terminals to convey a starting time segment and the number of time segments assigned to the terminal.

13. The apparatus of claim 12, wherein the at least one processor sends the spread data for the plurality of terminals on a High Speed Physical Downlink Shared Channel (HS-PDSCH), and sends the signaling for each terminal on a Shared Control Channel for HS-PDSCH (HS-SCCH).

14. The apparatus of claim 1, wherein the at least one processor is configured to map the data for each terminal of the plurality of terminals and the pilot to time segments of a TTI of a High Speed Physical Downlink Shared Channel (HS-PDSCH).

15. A method comprising:

assigning multiple time segments of a transmission time interval (TTI) comprising a single subframe to a plurality of terminals;

mapping data for each terminal to at least one time segment assigned to the terminal;

spreading data in each of the multiple time segments with at least one channelization code used in the TTI;

mapping a pilot to at least one time segment designated for pilot transmission, the pilot comprising a predetermined data sequence associated with a base station and known by the plurality of terminals; and

spreading the pilot with the at least one channelization code used in the TTI.

16. The method of claim 15, wherein the assigning the multiple time segments comprises assigning each of the multiple time segments to one of the plurality of terminals.

17. The method of claim 15, wherein the assigning the multiple time segments comprises assigning the multiple time segments to the plurality of terminals for each of multiple streams being sent simultaneously, each terminal being assigned at least one time segment across the multiple streams.

18. An apparatus comprising:

means for assigning multiple time segments of a transmission time interval (TTI) comprising a single subframe to a plurality of terminals;

means for mapping data for each terminal to at least one time segment assigned to the terminal;

spreading data in each of the multiple time segments with at least one channelization code used in the TTI;

means for mapping a pilot to at least one time segment designated for pilot transmission, the pilot comprising a predetermined data sequence associated with a base station and known by the plurality of terminals; and

means for spreading the pilot with the at least one channelization code used in the TTI.

19. The apparatus of claim 18, wherein the means for assigning the multiple time segments comprises means for assigning each of the multiple time segments to one of the plurality of terminals.

20. The apparatus of claim 18, wherein the means for assigning the multiple time segments comprises means for assigning the multiple time segments to the plurality of terminals for each of multiple streams being sent simultaneously, each terminal being assigned at least one time segment across the multiple streams.

21. An apparatus comprising:

at least one processor to assign multiple time segments of a first transmission time interval (TTI) comprising a single subframe to a first set of a plurality of terminals, each terminal in the first set being assigned at least one time segment in the first TTI, to assign multiple channelization codes to a second set of a plurality of terminals in a second TTI, each terminal in the second set being assigned at least one channelization code for the entire second TTI, to map a pilot to at least one time segment designated for pilot transmissions in each of the first TTI and the second TTI, and to spread the pilot in the second TTI using the at least one channelization code for the entire second TTI, the pilot comprising a predetermined data sequence associated with a base station and known by the plurality of terminals; and

a memory coupled to the at least one processor.

22. The apparatus of claim 21, wherein each terminal in the first set is assigned the multiple channelization codes for the at least one time segment assigned to the terminal.

23. The apparatus of claim 21, wherein the at least one processor maps data for each terminal in the first set to the at least one time segment assigned to the terminal in the first TTI, and spreads data in each of the multiple time segments in the first TTI with the multiple channelization codes.

24. The apparatus of claim 21, wherein the at least one processor spreads data for each terminal in the second set with the at least one channelization code assigned to the terminal.

25. An apparatus comprising:

at least one processor to receive an assignment of at least one time segment from among multiple time segments of a transmission time interval (TTI) comprising a single subframe, to obtain input samples for the at least one time segment, to despread the input samples with at least one channelization code used in the TTI, to receive a pilot sent with the at least one channelization code in at least one time segment designated for pilot transmission, to despread the pilot using the at least one channelization code, and to derive a channel estimate based on the received pilot, wherein the subframes comprising the TTI are assigned to a plurality of terminals, and wherein the pilot comprises a predetermined data sequence associated with a base station and known by the plurality of terminals; and

a memory coupled to the at least one processor.

26. The apparatus of claim 25, wherein the at least one processor receives signaling indicative of a starting time segment and the number of time segments in the assignment.

27. The apparatus of claim 25, wherein the at least one processor derives channel quality indicator (CQI) based on the received pilot.

28. The apparatus of claim 25, wherein the at least one processor receives the assignment of the at least one time segment for multiple streams sent simultaneously from multiple transmit antennas, obtains input samples for the at least one time segment from multiple receive antennas, performs multiple-input multiple-output (MIMO) detection on the input samples to obtain detected samples for each of the multiple streams, and despreads the detected samples for each stream with the at least one channelization code to obtain despread symbols for the stream.

29. The apparatus of claim 28, wherein the at least one processor decodes the despread symbols for each stream and cancels interference due to each stream after successfully decoding the stream.

30. A method comprising:

receiving an assignment of at least one time segment from among multiple time segments of a transmission time interval (TTI) comprising a single subframe, wherein the subframes of the TTI are assigned to a plurality of terminals;

obtaining input samples for the at least one time segment;

despreading the input samples with at least one channelization code used in the TTI;

means for receiving a pilot sent with the at least one channelization code in at least one time segment designated for pilot transmission, the pilot comprising a predetermined data sequence associated with a base station and known by the plurality of terminals;

means for despreading the pilot using the at least one channelization code; and

means for deriving a channel estimate based on the received pilot.

31. The method of claim 30, the receiving the assignment comprises receiving the assignment of the at least one time segment for multiple streams sent simultaneously from multiple transmit antennas, the obtaining the input samples comprises obtaining input samples for the at least one time segment from multiple receive antennas, and the method further comprises performing multiple-input multiple-output (MIMO) detection on the input samples to obtain detected samples for each of the multiple streams, the despreading the input samples comprises despreading the detected samples for each stream with the at least one channelization code to obtain despread symbols for the stream.

32. The method of claim 31, further comprising:

decoding the despread symbols for each stream; and

canceling interference due to each stream after successfully decoding the stream.

33. An apparatus comprising:

means for receiving an assignment of at least one time segment from among multiple time segments of a transmission time interval (TTI) comprising a single subframe, wherein the subframes comprising the TTI are assigned to a plurality of terminals;

means for obtaining input samples for the at least one time segment;

means for despreading the input samples with at least one channelization code used in the TTI;

means for receiving a pilot sent with the at least one channelization code in at least one time segment designated for pilot transmission, the pilot comprising a predetermined data sequence associated with a base station and known by the plurality of terminals;

means for despreading the pilot using the at least one channelization code; and

means for deriving a channel estimate based on the received pilot.

34. The apparatus of claim 33, the means for receiving the assignment comprises means for receiving the assignment of the at least one time segment for multiple streams sent simultaneously from multiple transmit antennas, the means for obtaining the input samples comprises means for obtaining input samples for the at least one time segment from multiple receive antennas, the apparatus further comprises means for performing multiple-input multiple-output (MIMO) detection on the input samples to obtain detected samples for each of the multiple streams, the means for despreading the input samples comprises means for despreading the detected samples for each stream with the at least one channelization code to obtain despread symbols for the stream.

35. The apparatus of claim 34, further comprising:

means for decoding the despread symbols for each stream; and

means for canceling interference due to each stream after successfully decoding the stream.

36. A computer program product residing on a non-transitory processor-readable medium and comprising instructions configured to cause a processor to:

assign multiple time segments of a transmission time interval (TTI) comprising a single subframe to a plurality of terminals;

map data for each terminal to at least one time segment assigned to the terminal;

spread data in each of the multiple time segments with at least one channelization code used in the TTI;

map a pilot to at least one time segment designated for pilot transmission, the pilot comprising a predetermined data sequence associated with a base station and known by the plurality of terminals; and

spread the pilot with the at least one channelization code used in the TTI.

37. The computer program product of claim 36, wherein the instructions configured to cause the processor to assign are configured to cause the processor to assign each of the multiple time segments to one of the plurality of terminals.

38. The computer program product of claim 36, wherein the instructions configured to cause the processor to assign are configured to cause the processor to assign each terminal with at least one consecutive time segment among the multiple time segments of the TTI.

39. The computer program product of claim 36, wherein instructions configured to cause the processor to assign are configured to cause the processor to assign the multiple time segments to the plurality of terminal in an order determined by the number of time segments assigned to each terminal.

40. The computer program product of claim 36, wherein the instructions configured to cause the processor to assign are configured to cause the processor to assign the multiple time segments to the plurality of terminals in a sequential order based on the number of time segments assigned to each terminal, with a first terminal with most number of time segments being assigned first in the TTI and a last terminal with least number of time segments being assigned last in the TTI.

41. The computer program product of claim 36, wherein the instructions configured to cause the processor to assign are configured to cause the processor to assign the multiple time segments to the plurality of terminals in a sequential order based on the number of time segments assigned to each terminal, with a first terminal with least number of time segments being assigned first in the TTI and a last terminal with most number of time segments being assigned last in the TTI.

42. The computer program product of claim 36, wherein the instructions configured to cause the processor to assign are configured to cause the processor to assign at least one time segment such that each of the at least one time segment is assigned to one terminal, and assigns at least one other time segment such that each of the at least one other time segment is assigned to at least two terminals.

43. The computer program product of claim 36, wherein the instructions configured to cause the processor to assign are configured to cause the processor to assign at least one time segment such that each time segment is shared by at least two terminals with different channelization codes.

44. The computer program product of claim 36, wherein the instructions configured to cause the processor to assign are configured to cause the processor to assign the multiple time segments to the plurality of terminals for each of multiple streams being sent simultaneously.

45. The computer program product of claim 44, wherein the instructions configured to cause the processor to assign are configured to cause the processor to assign each terminal with at least one time segment across the multiple streams.

46. The computer program product of claim 36, further comprising instructions configured to cause the processor to scale the pilot to achieve equal transmit power for the pilot and the data for the plurality of terminals.

47. The computer program product of claim 36, further comprising instructions configured to cause the processor to generate signaling for each of the plurality of terminals to convey a starting time segment and the number of time segments assigned to the terminal.

48. The computer program product of claim 47, further comprising instructions configured to cause the processor to send the spread data for the plurality of terminals on a High Speed Physical Downlink Shared Channel (HS-PDSCH), and send the signaling for each terminal on a Shared Control Channel for HS-PDSCH (HS-SCCH).

49. The computer program product of claim 48, wherein the instructions configured to cause the processor to receive are configured to cause the processor to receive signaling indicative of a starting time segment and the number of time segments in the assignment.

50. A computer program product residing on a non-transitory processor-readable medium and comprising instructions configured to cause a processor to:

receive an assignment of at least one time segment from among multiple time segments of a transmission time interval (TTI) comprising a single subframe, wherein the subframes comprising the TTI are assigned to a plurality of terminals;

obtain input samples for the at least one time segment;

despread the input samples with at least one channelization code used in the TTI;

receive a pilot sent with the at least one channelization code in at least one time segment designated for pilot transmission, the pilot comprising a predetermined data sequence associated with a base station and known by the plurality of terminals;

despread the pilot using the at least one channelization code; and

derive a channel estimate based on the received pilot.

51. The computer program product of claim 50, further comprising instructions configured to cause the processor to derive channel quality indicator (CQI) based on the received pilot.

52. The computer program product of claim 51, further comprising instructions configured to cause the processor to decode the despread symbols for each stream and cancel interference due to each stream after successfully decoding the stream.

53. The computer program product of claim 50, wherein the instructions configured to cause the processor to receive are configured to cause the processor to receive the assignment of the at least one time segment for multiple streams sent simultaneously from multiple transmit antennas, the instructions configured to cause the processor to obtain are configured to cause the processor to obtain input samples for the at least one time segment from multiple receive antennas, the computer program processor further comprising instructions configured to cause the processor to:

perform multiple-input multiple-output (MIMO) detection on the input samples to obtain detected samples for each of the multiple streams; and

despread the detected samples for each stream with the at least one channelization code to obtain despread symbols for the stream.