Claims
- 1. A remote terminal spread-spectrum code division multiple access (CDMA) interference canceller for reducing interference in a received spread-spectrum CDMA signal having N channels, with each of the N channels identified by a distinct chip-code signal, comprising:
a plurality of means for generating a plurality of chip-code signals; a plurality of despreading means, with each of said despreading means responsive to the respective distinct chip-code signal identifying a corresponding one of the N channels, for simultaneously despreading a plurality of spread-spectrum channels of a spread-spectrum CDMA signal as a plurality of despread signals, respectively; a plurality of delay means providing proper timing for the plurality of chip-code signals; a plurality of means, responsive to the plurality of delayed chip-code signals, for simultaneously spread-spectrum processing the plurality of despread signals, respectively, with a chip-code-signal corresponding to a respective despread signal; means, for an ith chip-code signal, for simultaneously subtracting from the spread-spectrum CDMA signal, each of N−1 spread-spectrum-processed-despread signals, with the N−1 spread-spectrum-processed-despread signals excluding a spread-spectrum processed-despread signal of the ith despread signal, thereby generating a subtracted signal; and channel means for despreading the subtracted signal with the ith chip-code signal as an ith channel.
- 2. The remote terminal canceller of claim 1 wherein each of said plurality of despreading means includes:
a filter; a chip-code generator for generating a chip-code signal from a respective chip codeword; and a mixer coupled between said filter and said chip-code generator.
- 3. The remote terminal canceller of claim 1 wherein each of said plurality of despreading means includes a matched filter having an impulse response matched to a respective chip code-word.
- 4. The remote terminal canceller of claim 1 wherein said channel means includes:
a filter; a chip-code generator for generating a chip-code signal from a chip codeword corresponding to the ith channel; and a mixer coupled between said filter and said chip-code generator.
- 5. The remote terminal canceller of claim 2 wherein said channel means includes:
a filter; a chip-code generator for generating a chip-code signal from a chip codeword corresponding to the ith channel; and a mixer coupled between said filter and said chip-code generator.
- 6. The remote terminal canceller of claim 3 wherein said channel means includes:
a filter; a chip-code generator for generating a chip-code signal from a chip codeword corresponding to the ith channel; and a mixer coupled between said filter and said chip-code generator.
- 7. The remote terminal canceller of claim 3 wherein said channel-despreading means includes a matched filter having an impulse response matched to a chip codeword corresponding to the ith channel.
- 8. The remote terminal canceller of claim 1 wherein each of said despreading means includes a digital signal processor with a digital filter having an impulse response matched to a respective chip codeword.
- 9. The remote terminal canceller of claim 8 wherein said channel-despreading means includes a matched filter having an impulse response matched to a chip codeword corresponding to the ith channel.
- 10. The remote terminal canceller of claim 1 wherein said channel-despreading means includes a digital signal processor with digital matched filter having an impulse response matched to a chip codeword corresponding to the ith channel.
- 11. The remote terminal canceller of claim 8 wherein said channel-despreading means includes a surface acoustic wave (SAW) device having an impulse response matched to a chip codeword corresponding to the ith channel.
- 12. The remote terminal canceller of claim 1 wherein each of said plurality of despreading means includes a surface acoustic wave (SAW) device having an impulse response matched to a chip codeword corresponding to the ith channel.
- 13. The remote terminal canceller of claim 12 wherein said channel despreading means includes a matched filter having an impulse response matched to a chip codeword corresponding to the ith channel.
- 14. The remote terminal canceller of claim 12 wherein said channel despreading means includes a chip-code generator for generating a chip-code signal from a digital matched filter having an impulse response matched to a chip codeword corresponding to the ith channel.
- 15. The remote terminal canceller of claim 12 wherein said channel despreading means includes a surface acoustic wave (SAW) device having an impulse response matched to a chip codeword corresponding to the ith channel.
- 16. A remote terminal spread-spectrum code division multiple access (CDMA) interference canceller for reducing interference in a received spread-spectnum CDMA signal having N channels, with each of the N channels identified by a distinct chip-code signal, comprising:
a plurality of chip-code-signal generators for generating, simultaneously, a plurality of chip-code signals; a plurality of correlators, responsive to a plurality of distinct chip-code signals, for simultaneously despreading a plurality of spread-spectrum channels of a spread-spectrum CDMA signal as a plurality of despread signals, respectively; a plurality of delay devices coupled to said plurality of chip-code signal generators to provide proper timing for the plurality of chip-code signals as a timed plurality of chip-code signals, respectively; a plurality of mixers, responsive to the timed plurality of chip-code signals, for simultaneously spread-spectrum processing, the plurality of despread signals, respectively, with a chip-code-signal corresponding to a respective despread signal; a subtractor, for an ith chip-code signal, for simultaneously subtracting from the spread-spectrum CDMA signal, each of the N−1 spread-spectrum-processed-despread signals, with the N−1 spread-spectrum-processed-despread signals, excluding a spread-spectrum processed despread signal of the ith despread signal, thereby generating a subtracted signal; and a channel correlator for despreading the subtracted signal with the ith chip-code signal as an ith channel.
- 17. A remote terminal spread-spectrum code division multiple access (CDMA) interference canceller for reducing interference in a received spread-spectrum CDMA signal having N chip-code channels, with each of the N channels identified by a distinct chip-code signal, comprising:
a plurality of matched filters, responsive to a plurality of distinct chip-code signals, for simultaneously despreading a plurality of spread-spectrum channels of a spread-spectrum CDMA signal as a plurality of despread signals, respectively; a plurality of chip-code-signal generators, responsive to a plurality of despread signals from the plurality of matched filters, for generating a timed plurality of chip-code signals, respectively; a plurality of mixers, responsive to the plurality of despread signals from the plurality of matched filters and the timed plurality of chip-code signals from the plurality of chip-code-signal generators, respectively, for spread-spectrum processing, simultaneously, the plurality of despread signals, respectively, with a timed chip-code signal corresponding to a respective despread signal; a subtractor, for an ith chip-code signal, for subtracting from the spread-spectrum CDMA signal, simultaneously, each of the N−1 spread-spectrum-processed-despread signals, with the N−1 spread-spectrum-processed-despread signals not including a spread-spectrum processed despread signal of the ith despread signal, thereby generating a subtracted signal; and a channel matched filter for despreading the subtracted signal with the ith chip-code signal as an ith channel.
- 18. A remote terminal spread-spectrum code division multiple access (CDMA) interference canceller for reducing interference in a received spread-spectrum CDMA signal having N channels, with each of the N channels identified by a distinct chip-code signal, comprising:
a plurality of chip-code-signal generators for generating, simultaneously, a plurality of chip-code signals; a plurality of correlators, responsive to a plurality of distinct chip-code-signals, for simultaneously despreading a plurality of spread-spectrum channels of a spread-spectrum CDMA signal as a plurality of despread signals, respectively; a plurality of delay devices coupled to said plurality of chip-code signal generators to provide proper timing for the plurality of chip-code signals as a timed plurality of chip-code signals, respectively; a plurality of mixers, responsive to the timed plurality of chip-code signals, for simultaneously spread-spectrum processing the plurality of despread signals, respectively, with a chip-code-signal corresponding to a respective despread signal, producing N spread-spectrum-processed-despread signals; a plurality of subtractors, each of said plurality of subtractors for subtracting from the spread-spectrum CDMA signal all but a particular one of the N spread-spectrum-processed-despread signals, with the particular one of the N spread-spectrum-processed-despread signals being different for each of said plurality of subtractors, thereby generating a plurality of subtracted signals; and a plurality of channel correlators for despreading the plurality of subtracted signals with a particular one of the plurality of chip-code signals, respectively, as a plurality of channels.
- 19. A remote terminal spread-spectrum code division multiple access (CDMA) interference canceller for reducing interference in a received spread-spectrum CDMA signal having N channels, with each of the N channels identified by a distinct chip-code signal, comprising:
a plurality of chip-code-signal generators for generating, simultaneously, a plurality of chip-code signals; a plurality of correlators, responsive to a plurality of distinct chip-code-signals, for simultaneously despreading a plurality of spread-spectrum channels of a spread-spectrum CDMA signal as a plurality of despread signals, respectively; a plurality of delay devices coupled to said plurality of chip-code-signal generators to provide proper timing for the plurality of chip-code signals as a timed plurality of chip-code signals, respectively; a plurality of mixers, responsive to the timed plurality of chip-code signals, for simultaneously spread-spectrum processing the plurality of despread signals, respectively, with a chip-code signal corresponding to a respective despread signal, producing N spread-spectrum-processed-despread signals; a first subtractor, for subtracting from the spread-spectrum CDMA signal, all but a first one of the N spread-spectrum-processed-despread signals, a plurality of chip-code-signal generators, responsive to a plurality of despread signals from the plurality of matched filters, for generating, simultaneously, a timed plurality of chip-code signals, respectively; a plurality of mixers, responsive to the plurality of despread signals from the plurality of matched filters and the timed plurality of chip-code signals from the plurality of chip-code signal generators, respectively, for simultaneously spread-spectrum processing the plurality of despread signals, respectively, with a timed chip-code signal corresponding to a respective despread signal, producing N spread-spectrum-processed-despread signals; a plurality of subtractors, each of said plurality of subtractors for subtracting from the spread-spectrum CDMA signal all but a particular one of the N spread-spectrum-processed-despread signals, with the particular one of the N spread-spectrum-processed-despread signals being different for each of said plurality of subtractors, thereby generating a plurality of subtracted signals; and a plurality of channel-matched filters for despreading the plurality of subtracted signals with a particular one of the plurality of distinct chip-code signals, respectively, as a plurality of channels.
- 20. A remote terminal spread-spectrum code division multiple access (CDMA) interference canceller for reducing interference in a received spread-spectrum CDMA receiver signal having N channels, with each of the N channels identified by a distinct chip-code signal, comprising:
a plurality of matched filters, responsive to a plurality of distinct chip-code-signals, for simultaneously despreading a plurality of spread-spectrum channels of a spread-spectrum CDMA signal as a plurality of despread signals, respectively; a plurality of chip-code signal generators, responsive to a plurality of despread signals from the plurality of matched filters, for simultaneously generating a timed plurality of chip-code-signals generators, respectively; a plurality of mixers, responsive to the plurality of despread signals from the plurality of matched filters and the timed plurality of chip-code signals from the plurality of chip-code-signal generators, respectively, for simultaneously spread-spectrum processing the plurality of despread signals, respectively, with a timed chip-code signal corresponding to a respective despread signal, producing N spread-spectrum-processed-despread signals; a first subtractor, for subtracting from the spread-spectrum CDMA signal, all but a first one of the N spread-spectrum-processed-despread signals, thereby generating a first subtracted signal; a second subtractor, for subtracting from the spread-spectrum CDMA signal, all but a second one of the N spread-spectrum-processed-despread signals, thereby generating a second subtracted signal; and an nth subtractor, for subtracting from the spread-spectrum CDMA signal, all but an nth one of the N spread-spectrum-processed-despread signals, thereby generating an nth subtracted signal; a first channel-matched filter for despreading the first subtracted signal with a first chip-code signal as an estimate of a first channel; a second channel-matched filter for despreading the second subtracted signal with a second chip-code signal as an estimate of a second channel; and an nth channel-matched filter for despreading the nth subtracted signal with an nth chip-code signal as an estimate of an nth channel. espread channels other than that channel.
- 21. A remote unit having a receiver for recovering data transmitted over a plurality of channels employing a wireless code division multiple access communication technique, the receiver comprising:
a unit for receiving the plurality of channels as a received signal, each channel associated with a code; and a unit for subtracting for each of the plurality of channels, others of the plurality of channels from the received signal and despreading a result of the subtraction as data for that channel.
- 22. The remote unit receiver of claim 21 wherein the subtracting unit includes, for each channel:
a unit for despreading the received signal with the others channels codes; a unit for respreading the despread others channel codes; and a unit for subtracting from the received signal the respread other channels.
- 23. The remote unit receiver of claim 22 wherein the despreading means is a mixer.
- 24. The remote unit receiver of claim 22 wherein the despreading means is a matched filter.
- 25. A remote unit receiver for recovering data transmitted over a plurality of channels employing a wireless code division multiple access communication technique, comprising:
a unit for receiving the plurality of channels as a received signal, each channel associated with a code; and for each of the plurality of channels, a subtractor for subtracting others of the plurality of channels from the received signal and despreading a result of that subtraction as data for that channel.
- 26. The remote unit receiver of claim 25 further comprising:
for each channel, a first mixer operatively coupled to the input for despreading the received signal with that channel code; for each channel, a second mixer for respreading that channel despread signal; and wherein for each channel, the subtractor subtracts from the received signal the respread channels other than that channel.
- 27. The remote unit of claim 25 further comprising;
for each channel, a matched filter operatively coupled to the receiving unit for despreading the received signal with that channel code; for each channel, a mixer for respreading that channel despread signal; and wherein for each channel, the subtractor subtracts from the received signal the respread channels other than that channel.
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of application Ser. No. 09/851,740, filed May 9, 2001, which is a continuation of application Ser. No. 09/276,019, filed Mar. 25, 1999, now U.S. Pat. No. 6,259,688, which is a continuation of U.S. application Ser. No. 08/939,146, filed Sep. 29, 1997, now U.S. Pat. No. 6,014,373, which is a continuation of U.S. application Ser. No. 08/654,994, filed May 29, 1996, now U.S. Pat. No. 5,719,852, which is a continuation of U.S. application Ser. No. 08/279,477, filed Jul. 26, 1994, now U.S. Pat. No. 5,553,062, which is a continuation-in-part of U.S. application Ser. No. 08/051,017, filed Apr. 22, 1993, now U.S. Pat. No. 5,363,403, all of which are incorporated herein by reference.
Continuations (5)
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Number |
Date |
Country |
Parent |
09851740 |
May 2001 |
US |
Child |
10201797 |
Jul 2002 |
US |
Parent |
09276019 |
Mar 1999 |
US |
Child |
09851740 |
May 2001 |
US |
Parent |
08939146 |
Sep 1997 |
US |
Child |
09276019 |
Mar 1999 |
US |
Parent |
08654994 |
May 1996 |
US |
Child |
08939146 |
Sep 1997 |
US |
Parent |
08279477 |
Jul 1994 |
US |
Child |
08654994 |
May 1996 |
US |
Continuation in Parts (1)
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Number |
Date |
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Parent |
08051017 |
Apr 1993 |
US |
Child |
08279477 |
Jul 1994 |
US |