Claims
- 1. A method of transmitting an identifying signal in an orthogonal frequency division multiplexing system, comprising the steps of:
modulating said signal; transforming said modulated signal to create an OFDM signal having a plurality of sub-carriers; and transmitting an identifying signal on inactive sub-carriers, wherein said identifying signal identifies a transmitter.
- 2. The method of claim 1, wherein said modulation step further comprises the step of differentially modulating said signal in the frequency domain.
- 3. The method of claim 1, wherein said inactive sub-carriers will be modulated in accordance with a predefined transmitter identifier information value.
- 4. The method of claim 1, wherein said inactive sub-carriers carrying said identifying signal are transmitted at a reduced power.
- 5. The method of claim 1, further comprising the step of mapping said identifying value onto a set of complex symbols.
- 6. The method of claim 1, wherein said inactive sub-carriers carrying said identifying signal are transmitted with each OFDM symbol.
- 7. The method of claim 1, wherein said transforming step implements a Fast Fourier Transform.
- 8. The method of claim 1, wherein said transforming step implements an orthogonal transform.
- 9. An orthogonal frequency division multiplexing transmitter for transmitting an OFDM signal, comprising:
an encoder for modulating said OFDM signal; a transformer for creating said OFDM signal having a plurality of sub-carriers; and means for inserting an identifying signal on inactive sub-carriers, wherein said identifying signal identifies a transmitter.
- 10. The transmitter of claim 9, wherein said encoder differentially modulates said signal in the frequency domain.
- 11. The transmitter of claim 9, wherein said inactive sub-carriers will be modulated in accordance with a predefined transmitter identifier information value.
- 12. The transmitter of claim 9, wherein said inactive sub-carriers carrying said identifying signal are transmitted at a reduced power.
- 13. The transmitter of claim 9, wherein said identifying value is mapped onto a set of complex symbols.
- 14. The transmitter of claim 9, wherein said inactive sub-carriers carrying said identifying signal are transmitted with each OFDM symbol.
- 15. The transmitter of claim 9, wherein said transformer a Fast Fourier Transform.
- 16. The transmitter of claim 9, wherein said transformer implements an orthogonal transform.
- 17. A method of receiving an identifying signal in an orthogonal frequency division multiplexing system, comprising the steps of:
transforming said received signal to recover an OFDM signal in the frequency domain having a plurality of sub-carriers; decoding said OFDM signal; and processing an identifying signal received on inactive sub-carriers, wherein said identifying signal identifies a transmitter.
- 18. The method of claim 17, wherein said decoding step further comprises the step of differentially demodulating said signal in the frequency domain.
- 19. The method of claim 17, wherein said inactive sub-carriers will be demodulated in accordance with a predefined transmitter identifier information value.
- 20. The method of claim 17, wherein said inactive sub-carriers carrying said identifying signal are received at a reduced power.
- 21. The method of claim 17, wherein said inactive sub-carriers carrying said identifying signal are received with each OFDM symbol.
- 22. The method of claim 17, wherein said transforming step implements a Fast Fourier Transform.
- 23. The method of claim 17, wherein said transforming step implements an orthogonal transform.
- 24. An orthogonal frequency division multiplexing receiver for receiving an OFDM signal, comprising:
a transformer for transforming said received signal to recover an OFDM signal in the frequency domain having a plurality of sub-carriers; a decoder for demodulating said OFDM signal; and means for processing an identifying signal received on inactive sub-carriers, wherein said identifying signal identifies a transmitter.
- 25. The receiver of claim 24, wherein said decoder differentially demodulates said signal in the frequency domain.
- 26. The receiver of claim 24, wherein said inactive sub-carriers will be demodulated in accordance with a predefined transmitter identifier information value.
- 27. The receiver of claim 24, wherein said inactive sub-carriers carrying said identifying signal are received at a reduced power.
- 28. The receiver of claim 24, wherein said inactive sub-carriers carrying said identifying signal are received with each OFDM symbol.
- 29. The receiver of claim 24, wherein said transformer implements a Fast Fourier Transform.
- 30. The receiver of claim 24, wherein said transformer implements an orthogonal transform.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 09/398,503, filed on Sep. 17, 1999.
Continuations (1)
|
Number |
Date |
Country |
Parent |
09398503 |
Sep 1999 |
US |
Child |
10763595 |
Jan 2004 |
US |