EP0446024A2
Expired / Lapsed
EP
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Spread-spectrum communication system
Assignee: Canon Inc
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Filing: 1991-03-05
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Granted: —
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Expires: 2011-03-05
Abstract
Abstract In order to eliminate the need for spread-spectrum code synchronization, a code divided into a suitable number of digits is applied to a transmitter and a receiver. The transmitter multiplies an original signal by each subdivision of the code to produce n-number of new baseband signals. Carrier waves having n-types of frequencies are modulated by these signals and the modulated signals are added to obtain an ultra-wide band signal, which is then transmitted to the receiver. The receiver separates the received signal into the narrow band components which prevailed prior to the adding operation in the transmitter, and then demodulates each component into a baseband signal. Each of these demodulated signals is multiplied by a code the same as that on the transmitting side, whereby n-number of original signals are obtained. Original signals obtained from a signal spread by a code different from that of the receiver are not n in number. Thus, spread-spectrum communication can be realized without requiring spread-spectrum code synchronization.
Inventors
- 👤 Ichiro Kato
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-29 15:41
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/26; H04L27/2601; H04L27/2647; H04L27/2649; H04L27/2653; H04B; H04B1/00; H04B1/69; H04L27/2626; H04L27/2627; H04L27/2637
Claims Analysis
Total Claims: 24
Claim 1
Independent Claim
81 words
A spread-spectrum signal transmitting apparatus comprising: first generating means for generating, in parallel, a plurality of carrier-wave signals having frequencies that differ from one another; second generating means for generating a spread-spectrum code sequence having a plurality of codes; and modulating means for modulating each of the plurality of carrier-wave signals, which are generated by said first generating means, based upon information to be transmitted and upon a respective one of the plurality of codes generated by said second generating means.
Claim 2
Dependent Claim
17 words
The apparatus according to claim 1, wherein said first generating means has a plurality of local oscillators.
Claim 3
Dependent Claim
32 words
The apparatus according to claim 1, wherein said second generating means generates codes the number of which is the same as the number of carrier-wave signals generated by said first generating means.
Claim 4
Dependent Claim
41 words
The apparatus according to claim 1, wherein said second generating means generates a spread-spectrum code sequence having digits the number of which is the same as, or a whole-number multiple of, the number of frequencies generated by said first generating means.
Claim 5
Dependent Claim
29 words
The apparatus according to claim 1, wherein said modulating means modulates each of the plurality of carrier-wave signals, which are generated by said first generating means, into a frequency.
Claim 6
Dependent Claim
66 words
The apparatus according to claim 1, wherein said modulating means has multipliers the number of which is the same as the number of the plurality of codes generated by said second generating means; transmitted information being supplied in parallel to respective ones of said multipliers, each multiplier multiplying the transmitted information by a respective one of the plurality of codes generated by said second generating means.
Claim 7
Dependent Claim
33 words
The apparatus according to claim 6, wherein said modulating means modulates the plurality of carrier-wave signals, which are generated by said first generating means, based upon respective ones of outputs from said multipliers.
Claim 8
Dependent Claim
73 words
A spread-spectrum signal transmitting apparatus comprising: a plurality of multiplying means for multiplying a value of each digit of a spread-spectrum code sequence, or values in which a plurality of digits of the spread-spectrum code sequence form one set, by the same digits of information to be transmitted; and modulating means for modulating outputs of the plurality of multiplying means by respective ones of carrier waves having frequencies that differ from one another.
Claim 9
Dependent Claim
22 words
The apparatus according to claim 8, wherein the information to be transmitted is supplied to said plurality of multiplying means in parallel.
Claim 10
Dependent Claim
16 words
The apparatus according to claim 8, wherein said modulating means has a plurality of local oscillators.
Claim 11
Dependent Claim
74 words
A spread-spectrum signal receiving apparatus comprising: generating means for generating a spread-spectrum code sequence having a plurality of codes; reverse spreading means for reverse-spreading a received signal, for every one of a plurality of frequency bands, based upon each of the plurality of codes generated by said generating means; and decision means for discriminating original data based upon a reverse-spread output produced by said reverse spreading means every frequency band of the received signal.
Claim 12
Dependent Claim
50 words
The apparatus according to claim 11, wherein said reverse spreading means has multipliers the number of which is the same as the number of codes generated by said generating means; each multiplier multiplying the received signal by a respective one of the plurality of codes generated by said generating means.
Claim 13
Dependent Claim
35 words
The apparatus according to claim 12, wherein said generating means generates a spread-spectrum code sequence having digits the number of which is the same as, or a whole-number multiple of, the number of multiplying means.
Claim 14
Dependent Claim
27 words
The apparatus according to claim 11, wherein said reverse spreading means has a plurality of band-pass filters for splitting the received signal into a plurality of bandwidths.
Claim 15
Dependent Claim
49 words
The apparatus according to claim 11, wherein said decision means has adding means for adding the reverse-spread outputs produced by said reverse spreading means for every one of a plurality of frequency bands; said decision means discriminating the original data based upon a sum output from said adding means.
Claim 16
Dependent Claim
67 words
A spread-spectrum signal receiving apparatus comprising: a plurality of multiplying means for multiplying the received signal by a value of each digit of a spread-spectrum code sequence, or values in which a plurality of digits of the spread-spectrum code sequence form one set, said multiplication being performed every corresponding carrier-wave frequency; and decision means for discriminating original data based upon outputs from said plurality of multiplying means.
Claim 17
Dependent Claim
27 words
The apparatus according to claim 16, wherein said reverse spreading means has a plurality of band-pass filters for splitting the received signal into a plurality of bandwidths.
Claim 18
Dependent Claim
37 words
The apparatus according to claim 16, wherein said decision means has adding means for adding outputs from said plurality of multiplying means; said decision means discriminating the original data based upon an output from said adding means.
Claim 19
Independent Claim
26 words
A method of generating a spread-spectrum signal corresponding to a sequential input symbol sequence, comprising generating, for each input symbol, a plurality of different frequencies simultaneously.
Claim 20
Dependent Claim
22 words
Spread-spectrum transmission apparatus comprising means for generating, in response to each symbol of an input sequence, a plurality of different frequencies simultaneously.
Claim 21
Dependent Claim
27 words
Apparatus according to claim 20, in which the values of said plurality of frequencies are selected in accordance with a predetermined sequence, and differ for successive symbols.
Claim 22
Dependent Claim
30 words
A spread-spectrum communication receiver including synchronization means for matching a predetermined spectrum spreading sequence to an incoming signal, in which the matching operation is performable within a single symbol period.
Claim 23
Independent Claim
61 words
A method of synchronizing a receiver to a spread-spectrum signal comprising, for each symbol, a plurality of simultaneous frequencies comprising the repeated step of demodulating the signal using a predetermined combination of frequency values, said predetermined combinations comprising a predetermined sequence of such combinations, and measuring the signal subsequent to each said repeated step, until a predetermined signal condition is detected.
Claim 24
Independent Claim
39 words
A method of spread-spectrum communcation, comprising employing a predetermined spreading sequence, characterized in that each item of said sequence comprises a multi-symbol vector each symbol of a said vector having an independent effect on said spreading of said signal.
References Cited (Backward Citations)
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