US5757845A — Adaptive spread spectrum receiver

Claim 1

Independent Claim 116 words

An adaptive spread spectrum receiver comprising: sample means which samples a received signal at regular time intervals and outputs sampled signals; and signal extraction means which despreads and linearly combines said sampled signals and outputs a combined signal; wherein said signal extraction means comprises: despreading/combining means which despreads and linearly combines said sampled signals by use of weighting coefficients to obtain said combined signal and outputs said combined signal and signals to be multiplied by said weighting coefficients; and coefficient control means which is supplied with said signal to be multiplied and said combined signal and calculates said weighting coefficients which minimize the average power of said combined signal under a constraint on said weighting coefficients.

Claim 2

Dependent Claim 116 words

An adaptive spread spectrum receiver comprising: sample means which samples a received signal at regular time intervals and outputs sampled signals; and signal extraction means which despreads and linearly combines said sampled signals and outputs a combined signal; wherein said signal extraction means comprises: despreading/combining means which despreads and linearly combines said sampled signals by use of weighting coefficients to obtain said combined signal and outputs said combined signal and signals to be multiplied by said weighting coefficients; and coefficient control means which is supplied with said signal to be multiplied and said combined signal and calculates said weighting coefficients which minimize the average power of said combined signal under a constraint on said weighting coefficients.

Claim 3

Dependent Claim 69 words

The adaptive spread spectrum receiver of claim 1, wherein said despreading/combining means comprises: despreading means which despreads said sampled signals by a plurality of despreading codes into a plurality of despread signals and outputs said plurality of despread signals as said signals to be multiplied; and linearly combining means which multiplies said plurality of despread signals by said weighting coefficients and combines the multiplied signals into said combined signal.

Claim 4

Dependent Claim 36 words

The adaptive spread spectrum receiver of claim 2, wherein said plurality of despreading codes of said despreading means is composed of a spreading code of a desired signal and one or more spreading codes orthogonal thereto.

Claim 5

Dependent Claim 54 words

The adaptive spread spectrum receiver of claim 1, wherein said despreading/combining part is means which convolutes a sequence of said sampled signals and a sequence of said weighting coefficients by a transversal filter and outputs the convoluted output as said combined signal and said sequence of sampled signals as said signals to be multiplied.

Claim 6

Dependent Claim 86 words

The adaptive spread spectrum receiver of claim 1, wherein said sample means is means which samples one or more received signals at regular time intervals and outputs one or more sampled signals; wherein said signal extraction means is diversity signal extraction means which despreads and linearly combines said sampled signals by said despreading/combining means and said coefficient control means and outputs a plurality of branch combined signals; and which comprises diversity demodulation means which diversity-combines/demodulates said plurality of branch combined signals and outputs a decision signal.

Claim 7

Dependent Claim 74 words

The adaptive spread spectrum receiver of claim 5, wherein said sample means is means which outputs, as said sampled signals, received signals generated from received waves of a plurality of antennas; and wherein said diversity signal extraction means is means which comprises said despreading/combining means and said coefficient control means for each of said sampled signals and outputs combined signals outputted by said plurality of despreading/combining means as said plurality of branch combined signals.

Claim 8

Dependent Claim 72 words

The adaptive spread spectrum receiver of claim 5, wherein said sample means is means which outputs, as a single sampled signal, a received signal generated from a received wave of a single antenna; and wherein said diversity signal extraction means is means which performs processings of said despreading/combining means and said coefficient control means with different timings and outputs the results of such signal processings as said plurality of branch combined signals.

Claim 9

Dependent Claim 123 words

The adaptive spread spectrum receiver of claim 7, wherein said despreading/combining means comprises: despreading means which despreads said sampled signal by a plurality of despreading codes to obtain a plurality of despread signals and outputs them as said signals to be multiplied; and a plurality of linearly combining means which sample said plurality of despread signals with different timings, multiply the sampled despread signals of different timings by weighting coefficients for the respective timings and combines the multiplied signals into said branch combined signals; and wherein said coefficient control means is a plurality of coefficient control means which uses, as said signals to be multiplied, said sampled despread signals sampled with said different timings and generate said weighting coefficients for said different timings.

Claim 10

Dependent Claim 84 words

The adaptive spread spectrum receiver of claim 8, wherein said plurality of despreading codes of said despreading means are a spreading code of a desired signal and one or more spreading codes orthogonal thereto; and wherein the timing for sampling said despread signals despread by said one or more spreading codes orthogonal to said spreading code of said desired signal is not synchronized with the timing of said despread signal despread by said spreading code of said desired signal in terms of sampling phase.

Claim 11

Dependent Claim 119 words

The adaptive spread spectrum receiver of claim 8, wherein said plurality of spreading codes of said despreading means are a spreading code of a desired signal and one or more spreading codes orthogonal to both of said spreading code of said desired signal and codes generated by shifting said spreading code of said desired signal in accordance with said timing, and the timing for sampling said despread signals despread by said one or more spreading codes orthogonal to both of said spreading code of said desired signal and codes generated by shifting said spreading code of said desired signal is synchronized with said despread signal despread by said spreading code of said desired signal in terms of sampling phase.

Claim 12

Dependent Claim 86 words

The adaptive spread spectrum receiver of claim 7, wherein said despreading/combining means is means which convolutes a sequence of said sampled signals and a sequence of said weighting coefficients by a transversal filter and outputs said plurality of branch combined signals and said sequence of sampled signals as said signals to be multiplied; and wherein said coefficient control means is means which outputs said weighting coefficients for said different timings on the basis of said signals to be multiplied and said plurality of branch combined signals.

Claim 13

Dependent Claim 29 words

The adaptive spread spectrum receiver of claim 1, wherein said sample means performs said sampling with a period shorter than a chip period of the code for said despreading.

Claim 14

Dependent Claim 66 words

The adaptive spread spectrum receiver of claim 2, 6, or 8, wherein said coefficient control means is means which calculates said weighting coefficients by using a correlation matrix of said plurality of despread signals, a steering vector using as its element the cross-correlation between said plurality of despreading codes and a despreading code of a desired signal, and a weighting coefficient constraint using said steering vector.

Claim 15

Dependent Claim 38 words

The adaptive spread spectrum of claim 13, wherein the period of said sampling is one half of a chip period and said despreading code of said desired signal has the number of elements doubled by interpolating its elements.

Claim 16

Dependent Claim 52 words

The adaptive spread spectrum receiver of claim 3, 9, or 10, wherein said coefficient control means is means which makes constant the weighting coefficient by which said despread signal of said desired signal is multiplied and calculates other weighting coefficients by use of a correlation matrix of said plurality of despread signals.

Claim 17

Dependent Claim 39 words

The adaptive spread spectrum receiver of claim 15, wherein the period of said sampling is one half of a chip period and said despreading code of said desired signal has the number of elements doubled by interpolating its elements.

Claim 18

Dependent Claim 60 words

The adaptive spread spectrum receiver of claim 4 or 11, wherein said coefficient control means is means which calculates said weighting coefficients by using a correlation matrix of said signals to be multiplied, a steering vector using each chip signal of a despreading code of a desired signal as its element and a weighting coefficient constraint using said steering vector.

Claim 19

Dependent Claim 51 words

The adaptive spread spectrum receiver of claim 17, wherein the period of said sampling is one half of a chip period and said steering vector has its number of elements doubled by interpolating elements of a steering vector in the case where the period of said sampling is the chip period.

Claim 20

Dependent Claim 30 words

The adaptive spread spectrum receiver of claim 1, wherein said coefficient control means is means which calculates said weighting coefficient by a recursive algorithm which satisfies a weighting coefficient constraint.

Claim 21

Dependent Claim 38 words

The adaptive spread spectrum receiver of claim 1, which receives, as said received signal, a transmitted signal generated by transmission processing means formed by a cascade connection of modulation means including a band limited filter and spreading means.

Claim 22

Dependent Claim 41 words

The adaptive spread spectrum receiver of claim 1, which receives, as said received signal, a transmitted signal generated by transmission processing means formed by a cascade connection of modulation means for a symbol waveform by an RZ signal and spreading means.

Claim 23

Dependent Claim 60 words

The adaptive spread spectrum receiver of claim 1, which receives, as said received signal, a transmitted signal generated by transmission processing means formed by a cascade connection of modulation means, spreading means and power control means which gradually increases the level of said transmitted signal over a period of time about the same as the time constant of said algorithm.

Claim 24

Dependent Claim 34 words

The adaptive spread spectrum receiver of claim 1, which receives, as said received signal, a transmitted signal generated by transmission processing means formed by a cascade connection of timing-shifted modulation means and spreading means.

Claim 25

Dependent Claim 47 words

The adaptive spread spectrum receiver of claim 1, which receives, as said received signal, a transmitted signal generated by transmission processing means formed by a cascade connection of frame generating means for generating a signal frame having periodically inserted thereinto training signals, modulation means and spreading means.

Annuity Stage	Window Opens	Payment Deadline	Surcharge Period Until	Estimated Fee	Status
3.5 Years (Year 4)	2001-05-25	2001-11-24	2002-05-26	$2000.00	Window Closed / Lapsed
7.5 Years (Year 8)	2005-05-25	2005-11-24	2006-05-26	$3760.00	Window Closed / Lapsed
11.5 Years (Year 12)	2009-05-25	2009-11-24	2010-05-26	$7700.00	Window Closed / Lapsed

Adaptive spread spectrum receiver

Abstract

Inventors

Bibliographic Details

Claims Analysis

References Cited (Backward Citations)

USPTO Annuity & Maintenance Windows

Assigned Categories & Tags

Assign Category Tag