Flexible time-frequency multiplexing structure for wireless communication

• US 8,077,595 B2
• Filed: 02/20/2007
• Issued: 12/13/2011
• Est. Priority Date: 02/21/2006
• Status: Active Grant

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Bhushan, Naga, Gorokhov, Alexei
• Primary Examiner(s): Ferris, Derrick
• Assistant Examiner(s): Crompton, Christopher R
• Application Number:
  US11/676,939
• Publication Number:
  US 20070195690A1
• Time in Patent Office: 1,757 Days
• Field of Search: 370/208
• US Class Current: 370/208
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT
• CPC Class Codes: H04L 5/0016 Time-frequency-code
• CPC Class Codes: H04L 5/0042 intra-user or intra-terminal allocation
• CPC Class Codes: H04L 5/0044 allocation of payload
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/0094 Indication of how sub-channels of the path are allocated

Abstract

Techniques for efficiently sending data in a wireless communication system are described. Code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) may be selected for each traffic segment, which may correspond to specific time frequency resources. An output waveform comprised of traffic and overhead segments may be generated. Each traffic segment may carry CDM data at a chip rate if CDM is selected or OFDM data if OFDM is selected. OFDM symbols may be generated at a sample rate that may be an integer ratio of the chip rate and may have a duration that may be determined based on the traffic segment duration. The output waveform may carry CDM data and/or OFDM data on subcarriers corresponding to at least one carrier in a spectral allocation and may further carry OFDM data on remaining usable subcarriers in the spectral allocation.

Claims

1. An apparatus comprising:

at least one processor to select code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) for each of multiple traffic segments within a traffic interval, and to generate an output waveform comprised of the multiple traffic segments, the each of the multiple traffic segments carrying CDM data if CDM is selected or OFDM data if OFDM is selected; and

a memory coupled to the at least one processor,

wherein the multiple traffic segments are segmented by frequency within the traffic interval,

wherein the at least one processor is capable of selecting CDM for a first traffic segment of the multiple traffic segments and OFDM for a second traffic segment of the multiple traffic segments and generating the output waveform comprised of the multiple traffic segments for simultaneous transmission, each of the multiple traffic segments carrying CDM data or OFDM data,

wherein the first and second traffic segments of the multiple traffic segments are in a same half-slot in a same carrier, and

wherein the output waveform further comprises at least one overhead segment comprising OFDM data.

2. The apparatus of claim 1, wherein the at least one processor generates the at least one overhead segment with overhead data and generates the output waveform comprised of the multiple traffic segments and the at least one overhead segment.

3. The apparatus of claim 1, wherein the at least one processor generates the at least one overhead segment with overhead data for multiple carriers, and generates the output waveform comprised of the multiple traffic segments and the at least one overhead segment for the multiple carriers.

4. The apparatus of claim 1, wherein the at least one processor generates a first waveform comprised of traffic segments carrying CDM data, generates a second waveform comprised of traffic segments carrying OFDM data, and generates the output waveform based on the first and second waveforms.

5. The apparatus of claim 1, wherein the at least one processor maps CDM data to subcarriers used for traffic segments carrying CDM data, maps OFDM data to subcarriers used for traffic segments carrying OFDM data, and generates the output waveform based on the mapped CDM data and OFDM data.

6. The apparatus of claim 1, wherein the each of the multiple traffic segments carries CDM data or OFDM data for unicast data sent to one terminal.

7. The apparatus of claim 1, wherein the multiple traffic segments comprise a guard band segment and the at least one processor is configured to select CDM data or OFDM data for the guard band segment.

8. A method within an apparatus, comprising:

selecting code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) for each of multiple traffic segments within a traffic interval; and

generating an output waveform comprised of the multiple traffic segments, the each of the multiple traffic segments carrying CDM data if CDM is selected or OFDM data if OFDM is selected,

wherein the multiple traffic segments are segmented by frequency within the traffic interval,

wherein the selecting comprises selecting CDM for a first traffic segment of the multiple traffic segments and OFDM for a second traffic segment of the multiple traffic segments,

wherein the generating comprises generating the output waveform comprised of the multiple traffic segments for simultaneous transmission,

wherein the first and second traffic segments of the multiple traffic segments are in a same half-slot in a same carrier, and

wherein the output waveform further comprises at least one overhead segment comprising OFDM data.

9. The method of claim 8, wherein the generating the output waveform comprises generating the output waveform comprised of the first and second traffic segments and the at least one overhead segment, the at least one overhead segment carrying overhead data.

10. An apparatus comprising:

means for selecting code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) for each of multiple traffic segments within a traffic interval; and

means for generating an output waveform comprised of the multiple traffic segments, the each of the multiple traffic segments carrying CDM data if CDM is selected or OFDM data if OFDM is selected,

wherein the multiple traffic segments are segmented by frequency within the traffic interval,

wherein the means for selecting is capable of selecting CDM for a first traffic segment of the multiple traffic segments and OFDM for a second traffic segment of the multiple traffic segments,

wherein the means for generating generates the output waveform comprised of the multiple traffic segments for simultaneous transmission,

wherein the first and second traffic segments of the multiple traffic segments are in a same half-slot in a same carrier, and

wherein the output waveform further comprises at least one overhead segment comprising OFDM data.

11. The apparatus of claim 10, wherein the means for generating the output waveform comprises means for generating the output waveform comprised of the first and second traffic segments and the at least one overhead segment, each of the first and second traffic segments carrying CDM data or OFDM data, and the at least one overhead segment carrying overhead data.

12. An apparatus comprising:

at least one processor configured to select code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) for a plurality of traffic segments within a traffic interval, the traffic segments being segmented by frequency within the traffic interval, to generate CDM data at a chip rate and to send the CDM data in a first traffic segment of the plurality of traffic segments within the traffic interval if CDM is selected for the first traffic segment, and to generate at least one OFDM symbol at a sample rate and to send the at least one OFDM symbol in a second traffic segment of the plurality of traffic segments within the traffic interval if OFDM is selected for the second traffic segment, the sample rate being related to the chip rate by an integer ratio, each OFDM symbol having a duration determined based on duration of the traffic interval, wherein the first and second traffic segments of the plurality of traffic segments are in a same half-slot in a same carrier, and wherein an overhead interval comprising at least one long OFDM symbol is time division multiplexed with the traffic interval; and

a memory coupled to the at least one processor.

13. The apparatus of claim 12, wherein the at least one processor generates the CDM data at a chip rate of 1.2288 mega chips/second (Mcps) if CDM is selected, and generates the at least one OFDM symbol at a sample rate of 1.2288xn mega samples/second (Msps) if OFDM is selected, where n is the integer ratio.

14. The apparatus of claim 12, wherein the at least one processor generates multiple OFDM symbols for the traffic interval if OFDM is selected, each OFDM symbol having a duration that is an integer divisor of the duration of the traffic interval.

15. The apparatus of claim 14, wherein the traffic interval spans 400 chips, and wherein each OFDM symbol has duration of 400 /m chips, where m is the integer divisor.

16. The apparatus of claim 12, wherein each OFDM symbol covers K subcarriers, where K is an integer that is not a power of two.

17. The apparatus of claim 12, wherein the at least one processor generates overhead data in accordance with CDM at the chip rate and time division multiplexes the overhead data in the overhead interval and the CDM data or the at least one OFDM symbol in the traffic interval.

18. The apparatus of claim 12, wherein the at least one processor generates CDM data at the chip rate for at least one carrier in a spectral allocation, and generates the at least one OFDM symbol at the sample rate for remaining usable subcarriers in the spectral allocation.

19. The apparatus of claim 18, wherein the at least one processor generates overhead data in accordance with CDM at the chip rate, generates the at least one long OFDM symbol at the sample rate, each long OFDM symbol having a duration determined based on duration of the overhead interval, and sends the overhead data and the at least one long OFDM symbol in the overhead interval.

20. The apparatus of claim 18, wherein the at least one processor generates a first waveform comprising the CDM data for the at least one carrier, generates a second waveform comprising the at least one OFDM symbol for the remaining usable subcarriers, and generates an output waveform based on the first and second waveforms.

21. A method within an apparatus, comprising:

selecting code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) for a plurality of traffic segments within a traffic interval, the traffic segments being segmented by frequency within the traffic interval;

generating CDM data at a chip rate and sending the CDM data in a first traffic segment of the plurality of traffic segments within the traffic interval if CDM is selected; and

generating at least one OFDM symbol at a sample rate and sending the at least one OFDM symbol in a second traffic segment of the plurality of traffic segments within the traffic interval if OFDM is selected, the sample rate being related to the chip rate by an integer ratio, each OFDM symbol having a duration determined based on duration of the traffic interval, wherein the first and second traffic segments of the plurality of traffic segments are in a same half-slot in a same carrier, and wherein an overhead interval comprising at least one long OFDM symbol is time division multiplexed with the traffic interval.

22. The method of claim 21, further comprising:

generating overhead data in accordance with CDM at the chip rate;

generating the at least one long OFDM symbol at the sample rate, each long OFDM symbol having a duration determined based on duration of the overhead interval; and

sending the overhead data and the at least one long OFDM symbol in the overhead interval.

23. An apparatus comprising:

means for selecting code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) for a plurality of traffic segments within a traffic interval, the traffic segments being segmented by frequency within the traffic interval;

means for generating CDM data at a chip rate and sending the CDM data in a first traffic segment of the plurality of traffic segments within the traffic interval if CDM is selected; and

means for generating at least one OFDM symbol at a sample rate and sending the at least one OFDM symbol in a second traffic segment of the plurality of traffic segments within the traffic interval if OFDM is selected, the sample rate being related to the chip rate by an integer ratio, each OFDM symbol having a duration determined based on duration of the traffic interval, wherein the first and second traffic segments of the plurality of traffic segments are in a same half-slot in a same carrier, and wherein an overhead interval comprising at least one long OFDM symbol is time division multiplexed with the traffic interval.

24. The apparatus of claim 23, further comprising:

means for generating overhead data in accordance with CDM at the chip rate;

means for generating the at least one long OFDM symbol at the sample rate, each long OFDM symbol having a duration determined based on duration of the overhead interval; and

means for sending the overhead data and the at least one long OFDM symbol in the overhead interval.

25. An apparatus comprising:

at least one processor configured to determine whether code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) is used for a plurality of traffic segments within a traffic interval, the traffic segments being segmented by frequency within the traffic interval, to process received samples to recover CDM data sent in a first traffic segment of the plurality of traffic segments, and to process the received samples to recover OFDM data sent in a second traffic segment of the plurality of traffic segments and in an overhead segment, wherein the first and second traffic segments of the plurality of traffic segments are in a same half-slot in a same carrier; and

a memory coupled to the at least one processor.

26. The apparatus of claim 25, wherein the at least one processor processes the received samples to recover overhead data in the overhead segment that is time division multiplexed with the traffic segment.

27. The apparatus of claim 25, wherein to recover the OFDM data the at least one processor processes the received samples to obtain received symbols for subcarriers used for the traffic segment, and processes the received symbols to recover the OFDM data sent in the traffic segment.

28. The apparatus of claim 25, wherein to recover the CDM data the at least one processor filters the received samples to obtain filtered samples for subcarriers used for the traffic segment, processes the filtered samples to obtain input samples for the traffic segment, decovers the input samples with multiple orthogonal codes to obtain received symbols, and processes the received symbols to recover the CDM data sent in the traffic segment.

29. The apparatus of claim 25, wherein to recover the CDM data the at least one processor processes the received samples to obtain frequency-domain symbols for a plurality of subcarriers, processes frequency-domain symbols for subcarriers used for the traffic segment to obtain time-domain samples, decovers the time-domain samples with multiple orthogonal codes to obtain received symbols, and processes the received symbols to recover the CDM data sent in the traffic segment.

30. A method within an apparatus, comprising:

determining whether code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) is used for a plurality of traffic segments within a traffic interval, the plurality of traffic segments being segmented by frequency within the traffic interval;

processing received samples to recover CDM data sent in a first traffic segment of the plurality of traffic segments; and

processing the received samples to recover OFDM data sent in a second traffic segment of the plurality of traffic segments and in an overhead segment, wherein the first and second traffic segments of the plurality of traffic segments are in a same half-slot in a same carrier.

31. The method of claim 30, further comprising:

processing the received samples to recover overhead data in the overhead segment that is time division multiplexed with the traffic segment.

32. An apparatus comprising:

means for determining whether code division multiplexing (CDM) or orthogonal frequency division multiplexing (OFDM) is used for a plurality of traffic segments within a traffic interval, the plurality of traffic segments being segmented by frequency within the traffic interval;

means for processing received samples to recover CDM data sent in a first traffic segment of the plurality of traffic segments; and

means for processing the received samples to recover OFDM data sent in a second traffic segment of the plurality of traffic segments and in an overhead segment, wherein the first and second traffic segments of the plurality of traffic segments are in a same half-slot in a same carrier.

33. The apparatus of claim 32, further comprising:

means for processing the received samples to recover overhead data in the overhead segment that is time division multiplexed with the traffic segment.