Multiple-access hybrid OFDM-CDMA system

• US 8,948,705 B2
• Filed: 09/08/2011
• Issued: 02/03/2015
• Est. Priority Date: 10/18/2001
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Walton, Jay R., Ketchum, John W., Howard, Steven J., Wallace, Mark
• Primary Examiner(s): Cumming, William D
• Application Number:
  US13/227,946
• Publication Number:
  US 20110317671A1
• Time in Patent Office: 1,244 Days
• Field of Search: 455/70, 370/203, 370/208, 370/210, 370/320, 370/336, 370/342, 370/343, 370/344, 370/329, 370/259, 370/280, 375/260, 375/299, 375/141, 375/208, 375/259, 375/340, 375/222, 375/233, 708/422, 382/100
• US Class Current: 455/70
• CPC Class Codes: H04B 1/692 Hybrid techniques using combinations of two or more spread spectrum techniques
• CPC Class Codes: H04L 25/0228 with direct estimation from sounding signals
• CPC Class Codes: H04L 27/0008 arrangements for allowing a transmitter or receiver to use more than one type of modulation negotiating modulation type for two-way transmission paths H04L5/1453
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/2613 Structure of the reference signals
• CPC Class Codes: H04L 27/2647 Arrangements specific to the receiver only equalisation H04L27/01
• CPC Class Codes: H04L 27/2655 Synchronisation arrangements
• CPC Class Codes: H04L 5/0021 in which codes are applied as a frequency-domain sequences, e.g. MC-CDMA
• CPC Class Codes: H04L 5/0048 Allocation of pilot signals, i.e. of signals known to the receiver
• CPC Class Codes: H04L 5/026 using code division
• CPC Class Codes: H04W 52/12 Outer and inner loops
• CPC Class Codes: H04W 52/286 during data packet transmission, e.g. high speed packet access [HSPA]

Abstract

In one aspect of a multiple-access OFDM-CDMA system, data spreading is performed in the frequency domain by spreading each data stream with a respective spreading code selected from a set of available spreading codes. To support multiple access, system resources may be allocated and de-allocated to users (e.g., spreading codes may be assigned to users as needed, and transmit power may be allocated to users). Variable rate data for each user may be supported via a combination of spreading adjustment and transmit power scaling. Interference control techniques are also provided to improve system performance via power control of the downlink and/or uplink transmissions to achieve the desired level of performance while minimizing interference. A pilot may be transmitted by each transmitter unit to assist the receiver units perform acquisition, timing synchronization, carrier recovery, handoff, channel estimation, coherent data demodulation, and so on.

Claims

1. A method for wireless communication, comprising:

spreading a modulation symbol with a spreading sequence to obtain a plurality of spread symbols;

transforming the plurality of spread symbols from frequency domain to time domain based on an inverse fast Fourier transform (IFFT) to obtain a plurality of time-domain samples; and

sending the plurality of time-domain samples via one or more antennas.

2. The method of claim 1, wherein the spreading the modulation symbol comprises multiplying the modulation symbol with a plurality of symbols of the spreading sequence to obtain the plurality of spread symbols, one spread symbol for each of the plurality of symbols of the spreading sequence.

7. The method of claim 1, wherein the spreading sequence is assigned to a terminal.

8. The method of claim 1, wherein the spreading sequence comprises a plurality of symbols of complex values.

3. A method for wireless communication, comprising:

spreading a modulation symbol with a spreading sequence to obtain a plurality of spread symbols;

transforming the plurality of spread symbols from frequency domain to time domain to obtain a plurality of time-domain samples;

appending a cyclic prefix to the plurality of time-domain samples prior to transmission; and

sending the plurality of time-domain samples via one or more antennas.

4. A method for wireless communication, comprising:

spreading a modulation symbol with a spreading sequence to obtain a plurality of spread symbols;

transforming the plurality of spread symbols from frequency domain to time domain to obtain a plurality of time-domain samples;

time division multiplexing the plurality of time-domain samples and a pilot; and

sending the plurality of time-domain samples via one or more antennas.

5. A method for wireless communication, comprising:

spreading a modulation symbol with a spreading sequence to obtain a plurality of spread symbols;

transforming the plurality of spread symbols from frequency domain to time domain to obtain a plurality of time-domain samples;

scaling the plurality of time-domain samples, or the plurality of spread symbols, or the modulation symbol based on a gain to obtain a target transmit power level; and

sending the plurality of time-domain samples via one or more antennas.

6. The method of claim 5, further comprising:

receiving a power control command; and

adjusting the gain based on the power control command.

9. An apparatus for wireless communication, comprising:

at least one processor configured to spread a modulation symbol with a spreading sequence to obtain a plurality of spread symbols and to transform the plurality of spread symbols from frequency domain to time domain based on an inverse fast Fourier transform (IFFT) to obtain a plurality of time-domain samples, and

at least one antenna associated with the at least one processor, wherein the at least one antenna is configured to send the plurality of time-domain samples.

10. The apparatus of claim 9, wherein the at least one processor is configured to multiply the modulation symbol with a plurality of symbols of the spreading sequence to obtain the plurality of spread symbols, one spread symbol for each of the plurality of symbols of the spreading sequence.

11. An apparatus for wireless communication, comprising:

at least one processor configured to spread a modulation symbol with a spreading sequence to obtain a plurality of spread symbols and to transform the plurality of spread symbols from frequency domain to time domain to obtain a plurality of time-domain samples,

wherein the at least one processor is configured to append a cyclic prefix to the plurality of time-domain samples prior to transmission, and

at least one antenna associated with the at least one processor, wherein the at least one antenna is configured to send the plurality of time-domain samples.

12. An apparatus for wireless communication, comprising:

at least one processor configured to spread a modulation symbol with a spreading sequence to obtain a plurality of spread symbols and to transform the plurality of spread symbols from frequency domain to time domain to obtain a plurality of time-domain samples,

wherein the at least one processor is configured to time division multiplex the plurality of time-domain samples and pilot, and

at least one antenna associated with the at least one processor, wherein the at least one antenna is configured to send the plurality of time-domain samples.

13. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one processor to spread a modulation symbol with a spreading sequence to obtain a plurality of spread symbols,

code for causing the at least one processor to transform the plurality of spread symbols from frequency domain to time domain based on an inverse fast Fourier transform (IFFT) to obtain a plurality of time-domain samples, and

code for causing the at least one processor to send the plurality of time-domain samples via one or more antennas.

14. A method for wireless communication, comprising:

receiving a plurality of time-domain samples via one or more antennas;

removing a cyclic prefix of the time-domain samples;

transforming the plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission after removing the cyclic prefix;

obtaining a plurality of received symbols for a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission; and

despreading the plurality of received symbols based on a spreading sequence to obtain a despread symbol.

16. The method of claim 14, wherein the despreading the plurality of received symbols comprises correlating the plurality of received symbols with a plurality of symbols determined based on the spreading sequence to obtain the despread symbol.

19. The method of claim 14, wherein the spreading sequence is assigned to a terminal.

20. The method of claim 14, wherein the spreading sequence comprises a plurality of symbols of complex values.

15. A method for wireless communication, comprising:

receiving a plurality of time-domain samples via one or more antennas;

transforming the plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission, wherein the transforming the plurality of time-domain samples comprises transforming the plurality of time-domain samples based on a fast Fourier transform (FFT) to obtain the received symbols for the subcarriers available for transmission;

obtaining a plurality of received symbols for a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission; and

despreading the plurality of received symbols based on a spreading sequence to obtain a despread symbol.

17. A method for wireless communication, comprising:

receiving a plurality of time-domain samples via one or more antennas;

time division demultiplexing the plurality of time-domain samples and a pilot;

transforming the plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission;

obtaining a plurality of received symbols for a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission; and

despreading the plurality of received symbols based on a spreading sequence to obtain a despread symbol.

18. The method of claim 17, further comprising:

determining a channel estimate based on the pilot; and

despreading the plurality of received symbols based further on the channel estimate.

21. An apparatus for wireless communication, comprising:

at least one processor configured to remove a cyclic prefix prior to transforming a plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission, to obtain a plurality of received symbols from a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission, and to despread the plurality of received symbols based on a spreading sequence to obtain a despread symbol; and

one or more antennas configured to receive and/or transmit the time domain samples and configured to be electrically coupled to the at least one processor.

23. The apparatus of claim 21, wherein the at least one processor is configured to correlate the plurality of received symbols with a plurality of symbols determined based on the spreading sequence to obtain the despread symbol.

22. An apparatus for wireless communication, comprising:

at least one processor configured to transform a plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission, to transform the plurality of time-domain samples based on a fast Fourier transform (FFT) to obtain the received symbols for the subcarriers available for transmission, and to despread the plurality of received symbols based on a spreading sequence to obtain a despread symbol; and

one or more antennas configured to receive and/or transmit the time domain samples and configured to be electrically coupled to the at least one processor.

24. An apparatus for wireless communication, comprising:

at least one processor is configured to time division demultiplex a plurality of time-domain samples and a pilot, to transform the plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission, to obtain a plurality of received symbols from a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission, and to despread the plurality of received symbols based on a spreading sequence to obtain a despread symbol; and

one or more antennas configured to receive and/or transmit the time domain samples and configured to be electrically coupled to the at least one processor.

25. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one processor to remove a cyclic prefix prior to transforming a plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission,

code for causing the at least one processor to obtain a plurality of received symbols for a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission, and

code for causing the at least one processor to despread the plurality of received symbols based on a spreading sequence to obtain a despread symbol.

26. A method for wireless communication, comprising:

generating modulation symbols comprising data multiplexed with control, wherein the generating comprises multiplexing power control commands with data;

spreading the modulation symbols with a spreading sequence to obtain a plurality of spread symbols;

transforming the plurality of spread symbols from frequency domain to time domain to obtain a plurality of time-domain samples; and

sending the plurality of time-domain samples via one or more antennas.

27. The method of claim 26, wherein the power control commands comprises downlink power control commands and the data comprises uplink data.

28. An apparatus for wireless communication, comprising:

one or more antennas;

at least one processor configured to generate modulation symbols comprising data multiplexed with control by multiplexing power control commands with data, spread the modulation symbols with a spreading sequence to obtain a plurality of spread symbols, transform the plurality of spread symbols from frequency domain to time domain to obtain a plurality of time-domain samples; and

a transmitter configured to send the plurality of time-domain samples via one or more antennas.

29. The apparatus of claim 28, wherein the power control commands comprises downlink power control commands and the data comprises uplink data.

30. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one processor to generate modulation symbols comprising data multiplexed with control, wherein the code for causing at least one processor to generate comprises code for multiplexing power control commands with data;

code for causing the at least one processor to spread the modulation symbols with a spreading sequence to obtain a plurality of spread symbols;

code for the at least one processor to transform the plurality of spread symbols from frequency domain to time domain to obtain a plurality of time-domain samples; and

code for causing the at least one processor to send the plurality of time-domain samples via one or more antennas.

31. The computer program product of claim 30, wherein the power control commands comprises downlink power control commands and the data comprises uplink data.

32. A method for wireless communication, comprising:

receiving a plurality of time-domain samples via one or more antennas, wherein the time-domain samples contain modulation symbols comprising data multiplexed with control, and wherein the received time-domain samples are power control commands multiplexed with data;

transforming the plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission;

obtaining a plurality of received symbols for a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission; and

despreading the plurality of received symbols based on a spreading sequence to obtain a despread symbol.

33. The method of claim 32, wherein the power control commands comprises downlink power control commands and the data comprises uplink data.

34. An apparatus for wireless communication, comprising:

a receiver configured to receive a plurality of time-domain samples, via one or more antennas, wherein the time-domain samples contain modulation symbols comprising data multiplexed with control, and wherein the received time-domain samples are power control commands multiplexed with data; and

at least one processor configured to transform the plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission, obtain a plurality of received symbols for a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission, and despread the plurality of received symbols based on a spreading sequence to obtain a despread symbol.

35. The apparatus of claim 34, wherein the power control commands comprises downlink power control commands and the data comprises uplink data.

36. A computer program product, comprising:

a non-transitory computer-readable medium comprising;

code for causing at least one processor to receive a plurality of time-domain samples via one or more antennas, wherein the time-domain samples contain modulation symbols comprising data multiplexed with control, and wherein the received time-domain samples are power control commands multiplexed with data;

code for causing the at least one processor to transform the plurality of time-domain samples from time domain to frequency domain to obtain received symbols for subcarriers available for transmission;

code for causing the at least one processor to obtain a plurality of received symbols for a plurality of subcarriers corresponding to a subset of the subcarriers available for transmission; and

code for causing the at least one processor to despread the plurality of received symbols based on a spreading sequence to obtain a despread symbol.

37. The computer program product of claim 36, wherein the power control commands comprises downlink power control commands and the data comprises uplink data.