Spread spectrum CDMA subtractive interference canceler system

Claim 3

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, 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 for delaying 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 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 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 n th subtractor, for subtracting from the spread-spectrum CDMA signal, all but an n th one of the N spread-spectrum-processed-despread signals, thereby generating an n th subtracted signal; a first channel correlator for despreading the first subtracted signal with a first timed chip-code signal as an estimate of a first channel; a second channel correlator for despreading the second subtracted signal with a second timed chip-code signal as an estimate of a second channel; an n th channel correlator for despreading the n th subtracted signal with an n th timed chip-code signal as an estimate of an n th channel signal; a first combiner for combining a first plurality of estimates of the first channel from said plurality of interference cancelers; a second combiner for combining a second plurality of estimates of the second channel from said plurality of interference cancelers; and an n th combiner for combining an n th plurality of estimates of the n th channel from said plurality of interference cancelers.

Claim 4

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, 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 for delaying 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 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 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 n th subtractor, for subtracting from the spread-spectrum CDMA signal, all but an n th one of the N spread-spectrum-processed-despread signals, thereby generating an n th subtracted signal; a first channel correlator for despreading the first subtracted signal with a first timed chip-code signal as an estimate of a first channel; a second channel correlator for despreading the second subtracted signal with a second timed chip-code signal as an estimate of a second channel; an n th channel correlator for despreading the n th subtracted signal with an n th timed chip-code signal as an estimate of an n th channel signal; a first combiner for combining a first plurality of estimates of the first channel from said plurality of interference cancelers; a second combiner for combining a second plurality of estimates of the second channel from said plurality of interference cancelers; and an n th combiner for combining an n th plurality of estimates of the n th channel from said plurality of interference cancelers.

Claim 5

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 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 the 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 spread-spectrum processing, simultaneously, the plurality of despread signals with a respective timed chip-code 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 n th subtractor, for subtracting from the spread-spectrum CDMA signal, all but an n th one of the N spread-spectrum-processed-despread signals, thereby generating an n th subtracted signal; a first channel-matched filter for despreading the first subtracted signal with a first timed chip-code signal as an estimate of a first channel; a second channel-matched filter for despreading the second subtracted signal with a second timed chip-code signal as an estimate of a second channel; an n th channel-matched filter for despreading the n th subtracted signal with an n th timed chip-code signal as an estimate of an n th channel; a first combiner for combining a first plurality of estimates of the first channel from said plurality of interference cancelers; a second combiner for combining a second plurality of estimates of the second channel from said plurality of interference cancelers; and an n th combiner for combining an n th plurality of estimates of the n th channel from said plurality of interference cancelers.

Claim 6

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 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 the 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 spread-spectrum processing, simultaneously, the plurality of despread signals with a respective timed chip-code 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 n th subtractor, for subtracting from the spread-spectrum CDMA signal, all but an n th one of the N spread-spectrum-processed-despread signals, thereby generating an n th subtracted signal; a first channel-matched filter for despreading the first subtracted signal with a first timed chip-code signal as an estimate of a first channel; a second channel-matched filter for despreading the second subtracted signal with a second timed chip-code signal as an estimate of a second channel; an n th channel-matched filter for despreading the n th subtracted signal with an n th timed chip-code signal as an estimate of an n th channel; a first combiner for combining a first plurality of estimates of the first channel from said plurality of interference cancelers; a second combiner for combining a second plurality of estimates of the second channel from said plurality of interference cancelers; and an n th combiner for combining an n th plurality of estimates of the n th channel from said plurality of interference cancelers.

Claim 9

The method as set forth in claim 4, further comprising the steps of: l. processing the first plurality of estimates, the second plurality of estimates, and the n th plurality of estimates as a plurality of processed estimates; m. inputting the plurality of processed estimates to a second plurality of interference cancelers; and n. repeating steps a through k, using the second plurality of interference cancelers.

Claim 10

A spread-spectrum code division multiple access (CDMA) interference-canceler system having a plurality of interference cancelers 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 chip-code-signal generators for generating, simultaneously, a plurality of chip-code signals; despreading means, 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 for delaying the plurality of chip-code signals as a plurality of timed-chip-code signals, respectively; a first spreading mixer for spread-spectrum processing a first despread signal, of the plurality of despread signals, with a first timed-chip-code signal, of the plurality of timed-chip-code signals, to produce a first spread-spectrum-processed-despread signal; a second spreading mixer for spread-spectrum processing a second despread signal, of the plurality of despread signals, with a second timed-chip-code signal, of the plurality of time-chip-code signals, to produce a second spread-spectrum-processed despread signal; an n th spreading mixer for spread-spectrum processing an n th despread signal, of the plurality of despread signals, with an n th timed-chip-code signal, of the plurality of timed-chip-code signals, to produce an n th spread-spectrum-processed-despread signal; a first subtractor, for subtracting from the spread-spectrum CDMA signal, all but the first spread-spectrum-processed-despread signal, thereby generating a first subtracted signal; a second subtractor, for subtracting from the spread-spectrum CDMA signal, all but the second spread-spectrum-processed-despread signal, thereby generating a second subtracted signal; and an n th subtractor, for subtracting from the spread-spectrum CDMA signal, all but the n th spread-spectrum-processed-despread signal, thereby generating an n th subtracted signal; a first channel correlator for despreading the first subtracted signal with a first timed-chip-code signal as an estimate of a first channel; a second channel correlator for despreading the second subtracted signal with a second timed-chip-code signal as an estimate of a second channel; an n th channel correlator for despreading the n th subtracted signal with an n th timed-chip-code signal as an estimate of an n th channel signal; a first combiner for combining a first plurality of estimates of the first channel from said plurality of interference cancelers as a first plurality of averaged estimates; a second combiner for combining a second plurality of estimates of the second channel from said plurality of interference cancelers as a second plurality of averaged estimates; an n th combiner for combining an n th plurality of estimates of the n th channel from said plurality of interference cancelers as an n th plurality of averaged estimates; and decision means for processing the first plurality of averaged estimates, the second plurality of averaged estimates, and the n th plurality of averaged estimates.

Claim 11

A spread-spectrum code division multiple access (CDMA) interference-canceler system having a plurality of interference cancelers 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 chip-code-signal generators for generating, simultaneously, a plurality of chip-code signals; despreading means, 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 for delaying the plurality of chip-code signals as a plurality of timed-chip-code signals, respectively; a first spreading mixer for spread-spectrum processing a first despread signal, of the plurality of despread signals, with a first timed-chip-code signal, of the plurality of timed-chip-code signals, to produce a first spread-spectrum-processed-despread signal; a second spreading mixer for spread-spectrum processing a second despread signal, of the plurality of despread signals, with a second timed-chip-code signal, of the plurality of time-chip-code signals, to produce a second spread-spectrum-processed despread signal; an n th spreading mixer for spread-spectrum processing an n th despread signal, of the plurality of despread signals, with an n th timed-chip-code signal, of the plurality of timed-chip-code signals, to produce an n th spread-spectrum-processed-despread signal; a first subtractor, for subtracting from the spread-spectrum CDMA signal, all but the first spread-spectrum-processed-despread signal, thereby generating a first subtracted signal; a second subtractor, for subtracting from the spread-spectrum CDMA signal, all but the second spread-spectrum-processed-despread signal, thereby generating a second subtracted signal; and an n th subtractor, for subtracting from the spread-spectrum CDMA signal, all but the n th spread-spectrum-processed-despread signal, thereby generating an n th subtracted signal; a first channel correlator for despreading the first subtracted signal with a first timed-chip-code signal as an estimate of a first channel; a second channel correlator for despreading the second subtracted signal with a second timed-chip-code signal as an estimate of a second channel; an n th channel correlator for despreading the n th subtracted signal with an n th timed-chip-code signal as an estimate of an n th channel signal; a first combiner for combining a first plurality of estimates of the first channel from said plurality of interference cancelers as a first plurality of averaged estimates; a second combiner for combining a second plurality of estimates of the second channel from said plurality of interference cancelers as a second plurality of averaged estimates; an n th combiner for combining an n th plurality of estimates of the n th channel from said plurality of interference cancelers as an n th plurality of averaged estimates; and decision means for processing the first plurality of averaged estimates, the second plurality of averaged estimates, and the n th plurality of averaged estimates.

Claim 12

The spread-spectrum CDMA interference-canceler system as set forth in claim 6, said plurality of delay devices comprising; a first delay device for delaying a first chip-code signal by a first time delay to generate a first timed-chip-code signal; a second delay device for delaying a second chip-code signal by a second time delay to generate a second timed-chip-code signal; and an n th delay device for delaying an n th chip-code signal by an n th time delay to generate an n th timed-chip-code signal.

Claim 13

The spread-spectrum CDMA interference-canceler system as set forth in claim 6, said despreading means comprising: a plurality of correlators.

Claim 14

The spread-spectrum CDMA interference-canceler system as set forth in claim 6, said despreading means comprising: a plurality of matched filters.

Claim 15

The spread-spectrum CDMA interference-canceler system as set forth in claim 9, said plurality of delay devices comprising; a first adjustment device for aligning a first chip-code signal with the first despread signal; a second adjustment device for aligning a second chip-code signal with the second despread signal; and an n th adjustment device for aligning an n th chip-code signal with the n th despread signal.

Claim 16

A spread-spectrum code division multiple access (CDMA) interference-canceler system having a plurality of interference cancelers 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 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 the plurality of despread signals from the plurality of matched filters, for generating, simultaneously, a plurality of timed-chip-code signals, respectively; a first spreading mixer for spread-spectrum processing a first despread signal, of the plurality of despread signals, with a first timed-chip-code signal, of the plurality of timed-chip-code signals, to produce a first spread-spectrum-processed-despread signal; a second spreading mixer for spread-spectrum processing a second despread signal, of the plurality of despread signals, with a second timed-chip-code signal, of the plurality of timed-chip-code signals, to produce a second spread-spectrum-processed-despread signal; an n th spreading mixer for spread-spectrum processing an n th despread signal, of the plurality of despread signals, with an n th timed-chip-code signal, of the plurality of timed-chip-code signals, to produce an n th spread-spectrum-processed-despread signal; a first subtractor, for subtracting from the spread-spectrum CDMA signal, all but the first spread-spectrum-processed-despread signal, thereby generating a first subtracted signal; a second subtractor, for subtracting from the spread-spectrum CDMA signal, all but the second spread-spectrum-processed-despread signal, thereby generating a second subtracted signal; and an n th subtractor, for subtracting from the spread-spectrum CDMA signal, all but the n th spread-spectrum-processed-despread signal, thereby generating an n th subtracted signal; a first channel-matched filter for despreading the first subtracted signal with the first timed-chip-code signal as an estimate of a first channel; a second channel-matched filter for despreading the second subtracted signal with the second timed-chip-code signal as an estimate of a second channel; an n th channel-matched filter for despreading the n th subtracted signal with the n th timed-chip-code signal as an estimate of an n th channel; a first combiner for combining a first plurality of estimates of the first channel from said plurality of interference cancelers; a second combiner for combining a second plurality of estimates of the second channel from said plurality of interference cancelers; an n th combiner for combining an n th plurality of estimates of the n th channel from said plurality of interference cancelers; and decision means for processing the combined estimates.

Claim 17

A spread-spectrum code division multiple access (CDMA) interference-canceler system having a plurality of interference cancelers 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 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 the plurality of despread signals from the plurality of matched filters, for generating, simultaneously, a plurality of timed-chip-code signals, respectively; a first spreading mixer for spread-spectrum processing a first despread signal, of the plurality of despread signals, with a first timed-chip-code signal, of the plurality of timed-chip-code signals, to produce a first spread-spectrum-processed-despread signal; a second spreading mixer for spread-spectrum processing a second despread signal, of the plurality of despread signals, with a second timed-chip-code signal, of the plurality of timed-chip-code signals, to produce a second spread-spectrum-processed-despread signal; an n th spreading mixer for spread-spectrum processing an n th despread signal, of the plurality of despread signals, with an n th timed-chip-code signal, of the plurality of timed-chip-code signals, to produce an n th spread-spectrum-processed-despread signal; a first subtractor, for subtracting from the spread-spectrum CDMA signal, all but the first spread-spectrum-processed-despread signal, thereby generating a first subtracted signal; a second subtractor, for subtracting from the spread-spectrum CDMA signal, all but the second spread-spectrum-processed-despread signal, thereby generating a second subtracted signal; and an n th subtractor, for subtracting from the spread-spectrum CDMA signal, all but the n th spread-spectrum-processed-despread signal, thereby generating an n th subtracted signal; a first channel-matched filter for despreading the first subtracted signal with the first timed-chip-code signal as an estimate of a first channel; a second channel-matched filter for despreading the second subtracted signal with the second timed-chip-code signal as an estimate of a second channel; an n th channel-matched filter for despreading the n th subtracted signal with the n th timed-chip-code signal as an estimate of an n th channel; a first combiner for combining a first plurality of estimates of the first channel from said plurality of interference cancelers; a second combiner for combining a second plurality of estimates of the second channel from said plurality of interference cancelers; an n th combiner for combining an n th plurality of estimates of the n th channel from said plurality of interference cancelers; and decision means for processing the combined estimates.

Claim 18

The spread-spectrum CDMA interference-canceler system as set forth in claim 11, said decision means comprising: a first decision device for processing the first combined plurality of estimates; a second decision device for processing the second combined plurality of estimates; and a third decision device for processing the third combined plurality of estimates.