Frequency division multiple access schemes for wireless communication

• US 8,582,548 B2
• Filed: 01/04/2006
• Issued: 11/12/2013
• Est. Priority Date: 11/18/2005
• Status: Expired due to Fees

• Current Assignee: Qualcomm, Inc.
• Original Assignee: Qualcomm, Inc.
• Inventors: Gore, Dhananjay Ashok, Palanki, Ravi
• Primary Examiner(s): Ho, Huy C
• Application Number:
  US11/325,980
• Publication Number:
  US 20070115795A1
• Time in Patent Office: 2,869 Days
• Field of Search: 370/344
• US Class Current: 370/344
• CPC Class Codes: H04B 1/00 Details of transmission systems, not covered by a single one of groups H04B3/00 - H04B13/00; Details of transmission systems not characterised by the medium used for transmission
• CPC Class Codes: H04B 1/0003 Software-defined radio [SDR] systems, i.e. systems wherein components typically implemented in hardware, e.g. filters or modulators/demodulators, are implented using software, e.g. by involving an AD or DA conversion stage such that at least part of the signal processing is performed in the digital domain digital baseband systems H04L25/00; digital modulation/demodulation H04L27/00; CDMA H04B1/707; TDMA H04B7/2643; image transmission H04N5/00
• CPC Class Codes: H04B 7/2621 using frequency division multiple access [FDMA] H04B7/2615 takes precedence
• CPC Class Codes: H04L 27/2602 Signal structure
• CPC Class Codes: H04L 27/2607 Cyclic extensions
• CPC Class Codes: H04L 27/2614 Peak power aspects
• CPC Class Codes: H04L 5/0007 the frequencies being orthogonal, e.g. OFDM(A), DMT

Abstract

Techniques for transmitting data using single-carrier frequency division multiple access (SC-FDMA) multiplexing schemes are described. In one aspect, data is sent on sets of adjacent subbands that are offset from one another to achieve frequency diversity. A terminal may be assigned a set of N adjacent subbands that is offset by less than N (e.g., N/2) subbands from another set of N adjacent subbands assigned to another terminal and would then observe interference on only subbands that overlap. In another aspect, a multi-carrier transmission symbol is generated with multi-carrier SC-FDMA. Multiple waveforms carrying modulation symbols in the time domain on multiple sets of subbands are generated. The multiple waveforms are pre-processed (e.g., cyclically delayed by different amounts) to obtain pre-processed waveforms, which are combined (e.g., added) to obtain a composite waveform. A cyclic prefix is appended to the composite waveform to generate the multi-carrier transmission symbol.

Claims

1. An apparatus comprising:

at least one processor configured to generate a transmission symbol carrying a set of modulation symbols in time domain on a first set of N adjacent subbands assigned to a first terminal, wherein the first set of N subbands is offset by less than N subbands from a second set of N adjacent subbands assigned to a second terminal such that the first set of N subbands and the second set of N subbands partially overlap, and wherein N is an integer greater than one; and

a memory coupled to the at least one processor.

2. The apparatus of claim 1, wherein the first set of N subbands is offset by N/2 subbands from the second set of N subbands.

3. The apparatus of claim 1, wherein the first set of N subbands is offset by less than N subbands from a third set of N adjacent subbands assigned to a third terminal, and wherein the second set of N subbands is offset by less than N subbands from the third set of N subbands.

4. The apparatus of claim 1, wherein the first and second terminals are in two sectors in a communication system.

5. The apparatus of claim 1, wherein the first and second terminals are in a single sector in a communication system.

6. The apparatus of claim 1, wherein the at least one processor is configured to transform the set of modulation symbols to frequency domain to obtain a first sequence of frequency domain values, to map the frequency domain values in the first sequence on the N subbands in the first set to obtain a second sequence, and to generate the transmission symbol with the second sequence.

7. The apparatus of claim 1, wherein the at least one processor is configured to map the set of modulation symbols to evenly spaced sample locations in a first sequence, to transform the first sequence to frequency domain to obtain a second sequence of frequency domain values, to zero out frequency domain values in the second sequence for subbands not included in the first set to obtain a third sequence, and to generate the transmission symbol with the third sequence.

8. A method comprising:

determining a first set of N adjacent subbands assigned to a first terminal, wherein the first set of N subbands is offset by less than N subbands from a second set of N adjacent subbands assigned to a second terminal such that the first set of N subbands and the second set of N subbands partially overlap, and wherein N is an integer greater than one; and

generating a transmission symbol carrying a set of modulation symbols in time domain on the first set of N subbands.

9. The method of claim 8, wherein the generating the transmission symbol comprises

transforming the set of modulation symbols to frequency domain to obtain a first sequence of frequency domain values,

mapping the frequency domain values in the first sequence on the N subbands in the first set to obtain a second sequence, and

generating the transmission symbol with the second sequence.

10. An apparatus comprising:

means for determining a first set of N adjacent subbands assigned to a first terminal, wherein the first set of N subbands is offset by less than N subbands from a second set of N adjacent subbands assigned to a second terminal such that the first set of N subbands and the second set of N subbands partially overlap, and wherein N is an integer greater than one; and

means for generating a transmission symbol carrying a set of modulation symbols in time domain on the first set of N subbands.

11. The apparatus of claim 10, wherein the means for generating the transmission symbol comprises

means for transforming the set of modulation symbols to frequency domain to obtain a first sequence of frequency domain values,

means for mapping the frequency domain values in the first sequence on the N subbands in the first set to obtain a second sequence, and

means for generating the transmission symbol with the second sequence.

12. An apparatus comprising:

at least one processor configured to receive a transmission symbol carrying a set of modulation symbols in time domain on a first set of N adjacent subbands assigned to a first terminal, and to process the received transmission symbol to recover the set of modulation symbols from the first set of N subbands, wherein the first set of N subbands is offset by less than N subbands from a second set of N adjacent subbands assigned to a second terminal such that the first set of N subbands and the second set of N subbands partially overlap, and wherein N is an integer greater than one; and

a memory coupled to the at least one processor.

13. The apparatus of claim 12, wherein the at least one processor is configured to transform the received transmission symbol to frequency domain to obtain a set of frequency-domain values for the first set of N subbands, and to transform the set of frequency-domain values to time domain to recover the set of modulation symbols.