Claims
- 1. A method employed by a remote terminal for reducing interference in a spread spectrum code division multiple access (CDMA) receiver having N channels wherein each of the N channels is identified by a distinct chip-code signal, comprising:
a) generating a plurality of chip-code signals; b) simultaneously despreading a plurality of spread spectrum channels of a spread spectrum CDMA signal; c) generating a timed version of the plurality of chip-code signals; d) spread spectrum processing the plurality of despread signals with a chip-code signal corresponding to a respective despread signal; e) subtracting from the spread spectrum CDMA signal N−1 spread spectrum process despread signals with N−1 spread spectrum process despread signals with the exception of a spread spectrum process despread of an ith despread signal to general a subtractive signal; and f) despreading a subtractive signal employ the ith chip-code signal as an ith channel.
- 2. The method of claim 1 wherein step (d) includes mixing each of the chip-code signals with a received spread spectrum CDMA signal and filtering each mixed signal.
- 3. The method of claim 2 wherein the filtering step includes providing filters for each channel, each filter having an impulse response which is matched to an associated chip-code word.
- 4. The method of claim 1 wherein step (c) further includes:
(g) mixing the output obtained at step (b) with a time delayed chip-code signal from a chip-code work corresponding the ith channel; and (h) integrating the output obtained from step (g).
- 5. A method employed by a remote terminal for reducing interference in a received spread spectrum code division multiple access (CDMA) N channel signal, with each of the N channels identified by a distinct chip-code signal, comprising:
a) despreading a spread spectrum CDMA received signal as a plurality of despread signals. b) simultaneously spread spectrum processing the plurality of despread signals employing a timed version of the plurality of chip-code signals with a chip-code signal corresponding to a respective despread signal; c) simultaneously subtracting from the spread spectrum CDMA signal each of N−1 spread spectrum process that despread signals employing N−1 spread spectrum processed despread signals, except for a spread spectrum processed ith despread signal, of an despread signal, to generate a subtractive signal; and d) despreading the subtractive signal employing the ith chip-code signal as an ith channel.
- 6. The method of claim 5 wherein step (a) includes correlating the spread spectrum CDMA signal into a plurality of despread signals.
- 7. The method of claim 5 wherein step (a) includes matched filtering the spread spectrum CDMA signal as a plurality of despread signals.
- 8. A method employed by a remote terminal for reducing interference in a received spread spectrum code division multiple access (CDMA) signal having N channels, with each of the N channels identified by a distinct chip-code signal through the use N groups of interference cancellers, comprising:
for each group of interference cancellers; simultaneously despreading a plurality of spread spectrum channels of a spread spectrum CDMA signal as a plurality of despread signals; simultaneously spread spectrum processing, using a time diversion of the plurality of chip-code signals, the plurality of despread signals each with a chip-code signal corresponding to a respective despread signal; subtracting from the spread spectrum CDMA signal N−1 spread spectrum processed signals in each interference canceller group the spread spectrum processed-despread signals omitting a different spread spectrum process despread signal of a first through an ith of the despread signal, each generating a subtractive signal; and despreading the subtracted signal of each group of interference cancellers with the chip-code signal of the omitted chip-code for that group of interference cancellers thereby providing N sets of estimates of the N channels.
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 |
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Parent |
09851740 |
May 2001 |
US |
Child |
10202129 |
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 |