Spread spectrum CDMA interference canceler system and method

Claim 2

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a plurality of interference cancelers, each of said plurality of interference cancelers including, means for generating a plurality of chip-code signals; means for despreading, using the plurality of chip-code signals, a spread-spectrum CDMA signal as a plurality of despread signals, respectively; means for timing the plurality of chip-code signals to generate a plurality of timed chip-code signals; means, responsive to the plurality of timed chip-code-signals, for spread-spectrum processing the plurality of despread signals with the plurality of timed chip-code-signals, respectively; means, for an i th chip-code signal, for subtracting from the spread-spectrum CDMA signal each of an N-1 plurality of spread-spectrum processed despread signals, with the N-1 plurality of spread-spectrum processed despread signals not including the i th spread-spectrum processed despread signal of an i th despread signal, thereby generating a subtracted signal; and channel means for despreading the subtracted signal with the i th timed chip-code signal as an i th channel signal.

Claim 3

The spread-spectrum CDMA interference canceler system as set forth in claim 1 with said despreading means including: 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.

Claim 4

The spread-spectrum CDMA interference canceler system as set forth in claim 2 with said channel means including: a filter; a chip-code generator for generating a chip-code signal from a chip codeword corresponding to the i th channel signal; and a mixer coupled between said filter and said chip-code generator.

Claim 5

The spread-spectrum CDMA interference canceler system as set forth in claim 1 with said despreading means including a matched filter having an impulse response matched to a respective chip codeword.

Claim 6

The spread-spectrum CDMA interference canceler system as set forth in claim 4 with said channel means including: a filter; a chip-code generator for generating a chip-code signal from a chip codeword corresponding to the i th channel signal; and a mixer coupled between said filter and said chip-code generator.

Claim 7

The spread-spectrum CDMA interference canceler system as set forth in claim 4 with said channel means including a matched filter having an impulse response matched to a chip codeword corresponding to the i th channel.

Claim 8

The spread-spectrum CDMA interference canceler system as set forth in claim 1 with said channel means including: a filter; a chip-code generator for generating a chip-code signal from a chip codeword corresponding to the i th channel signal; and a mixer coupled between said filter and said chip-code generator.

Claim 9

The spread-spectrum CDMA interference canceler system as set forth in claim 1 with said despreading means including a digital signal processor with digital matched filter having an impulse response matched to a respective chip codeword.

Claim 10

The spread-spectrum CDMA interference canceler system as set forth in claim 8 with said channel means including a matched filter having an impulse response matched to a chip codeword corresponding to the i th channel.

Claim 11

The spread-spectrum CDMA interference canceler system as set forth in claim 8 with said channel means including a surface acoustic wave (SAW) device having an impulse response matched to a chip codeword corresponding to the i th channel.

Claim 12

The spread-spectrum CDMA interference canceler system as set forth in claim 1 with said channel means including a digital signal processor with digital matched filter having an impulse response matched to a chip codeword corresponding to the i th channel.

Claim 13

The spread-spectrum CDMA interference canceler system as set forth in claim 1 with said despreading means including a surface acoustic wave (SAW) device having an impulse response matched to a chip codeword corresponding to the i th channel.

Claim 14

The spread-spectrum CDMA interference canceler system as set forth in claim 12 with said channel means including a matched filter having an impulse response matched to a chip codeword corresponding to the i th channel.

Claim 15

The spread-spectrum CDMA interference canceler system as forth in claim 12 with said channel means including 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 i th channel.

Claim 16

The spread-spectrum CDMA interference canceler system forth in claim 12 with said channel means including a surface acoustic wave (SAW) device having an impulse response matched to a chip codeword corresponding to the i th channel.

Claim 17

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a CDMA/DS detector for detecting and despreading a received spread-spectrum signal having a plurality of channels as a plurality of despread, spread-spectrum channels; a plurality of serially connected interference cancelers each for processing the plurality of despread, spread-spectrum channels and for outputting a respective plurality of estimates of the plurality of channels; and and a combiner for combining, using the outputs of the plurality of interference cancelers, a plurality of estimates of a particular channel to generate an averaged estimate.

Claim 18

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a CDMA/DS detector for detecting and despreading a received spread-spectrum signal having a plurality of channels as a plurality of despread, spread-spectrum channels; a plurality of serially connected interference cancelers each for processing the plurality of despread, spread-spectrum channels and for outputting a respective plurality of estimates of the plurality of channels; and and a combiner for combining, using the outputs of the plurality of interference cancelers, a plurality of estimates of a particular channel to generate an averaged estimate.

Claim 19

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a CDMA/DS detector for detecting and despreading a received spread-spectrum signal having a plurality of channels as a plurality of despread, spread-spectrum channels; a plurality of serially connected interference cancelers each for processing the plurality of despread, spread-spectrum channels and for outputting a respective plurality of estimates of the plurality of channels; means for combining, using the respective plurality of estimates from said plurality of interference cancelers, a first plurality of estimates for a first channel to generate a first averaged output for channel one, a second plurality of estimates for a second channel to generate a second averaged output for channel two, and an M th plurality of estimates for an M th channel to generate an M th averaged output for channel M; and decision means for processing the first averaged output for channel one, the second averaged output for channel two, and the M th averaged output for channel M.

Claim 20

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a CDMA/DS detector for detecting and despreading a received spread-spectrum signal having a plurality of channels as a plurality of despread, spread-spectrum channels; a plurality of serially connected interference cancelers each for processing the plurality of despread, spread-spectrum channels and for outputting a respective plurality of estimates of the plurality of channels; means for combining, using the respective plurality of estimates from said plurality of interference cancelers, a first plurality of estimates for a first channel to generate a first averaged output for channel one, a second plurality of estimates for a second channel to generate a second averaged output for channel two, and an M th plurality of estimates for an M th channel to generate an M th averaged output for channel M; and decision means for processing the first averaged output for channel one, the second averaged output for channel two, and the M th averaged output for channel M.

Claim 23

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a plurality of interference cancelers, each of said interference cancelers including, a plurality of chip-code-signal generators for generating, simultaneously, a plurality of chip-code signals; a plurality of correlators coupled to said plurality of chip-code generators through a plurality of mixers, each of said plurality of correlators responsive to a distinct chip-code signal of the plurality of 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 for delaying the plurality of chip-code signals as a timed plurality of chip-code signals, respectively; a plurality of processing mixers coupled to said plurality of delay devices and to said plurality of correlators, responsive to the timed plurality of chip-code signals, for spread-spectrum processing, simultaneously, 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 correlators for despreading the plurality of subtracted signals with a particular one of the plurality of timed chip-code signals, respectively, as a plurality of channel signals.

Claim 24

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a plurality of interference cancelers, each of said interference cancelers including, a plurality of chip-code-signal generators for generating, simultaneously, a plurality of chip-code signals; a plurality of correlators coupled to said plurality of chip-code generators through a plurality of mixers, each of said plurality of correlators responsive to a distinct chip-code signal of the plurality of 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 for delaying the plurality of chip-code signals as a timed plurality of chip-code signals, respectively; a plurality of processing mixers coupled to said plurality of delay devices and to said plurality of correlators, responsive to the timed plurality of chip-code signals, for spread-spectrum processing, simultaneously, 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 correlators for despreading the plurality of subtracted signals with a particular one of the plurality of timed chip-code signals, respectively, as a plurality of channel signals.

Claim 25

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a CDMA/DS detector for detecting and despreading a received spread-spectrum signal having a plurality of channels as a plurality of despread, spread-spectrum channels; a plurality of serially connected interference cancelers each for processing the plurality of despread, spread-spectrum channels and for outputting a respective plurality of estimates of the plurality of channels; and means for combining, using the respective plurality of estimates from said plurality of interference cancelers, a first plurality of estimates for a first channel to generate a first averaged output for channel one, a second plurality of estimates for a second channel to generate a second averaged output for channel two, and an M th plurality of estimates for an M th channel to generate an M th averaged output for channel M.

Claim 26

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a CDMA/DS detector for detecting and despreading a received spread-spectrum signal having a plurality of channels as a plurality of despread, spread-spectrum channels; a plurality of serially connected interference cancelers each for processing the plurality of despread, spread-spectrum channels and for outputting a respective plurality of estimates of the plurality of channels; and means for combining, using the respective plurality of estimates from said plurality of interference cancelers, a first plurality of estimates for a first channel to generate a first averaged output for channel one, a second plurality of estimates for a second channel to generate a second averaged output for channel two, and an M th plurality of estimates for an M th channel to generate an M th averaged output for channel M.

Claim 27

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a plurality of serially connected interference cancelers each for processing a plurality of despread, spread-spectrum channels and for outputting a plurality of estimates of a plurality of spread-spectrum channels corresponding to the plurality of despread, spread-spectrum channels, respectively; means for combining the plurality of estimates to produce a plurality of averaged estimates; and decision means for processing the plurality of averaged estimates.

Claim 28

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a plurality of serially connected interference cancelers each for processing a plurality of despread, spread-spectrum channels and for outputting a plurality of estimates of a plurality of spread-spectrum channels corresponding to the plurality of despread, spread-spectrum channels, respectively; means for combining the plurality of estimates to produce a plurality of averaged estimates; and decision means for processing the plurality of averaged estimates.

Claim 29

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a plurality of serially connected interference cancelers each for processing a plurality of despread, spread-spectrum channels and for outputting a plurality of estimates of a plurality of spread-spectrum channels corresponding to the plurality of despread, spread-spectrum channels, respectively; a plurality of combiners for combining the plurality of estimates to produce a plurality of averaged estimates; and a plurality of decision devices for processing the plurality of averaged estimates.

Claim 30

A spread-spectrum code division multiple access (CDMA) interference-canceler system for reducing interference in a spread-spectrum CDMA receiver having N channels, with each of the N channels identified by a distinct chip-code signal, comprising: a plurality of serially connected interference cancelers each for processing a plurality of despread, spread-spectrum channels and for outputting a plurality of estimates of a plurality of spread-spectrum channels corresponding to the plurality of despread, spread-spectrum channels, respectively; a plurality of combiners for combining the plurality of estimates to produce a plurality of averaged estimates; and a plurality of decision devices for processing the plurality of averaged estimates.