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Dual code spread spectrum communication system

a communication system and dual-code technology, applied in the field of direct sequence spectrum spreading (dsss) communication systems, can solve the problems of difficult acquisition without advance, rendering isolation and reception of input signals difficult without advance, and signal cannot be reconstituted nor detected

Inactive Publication Date: 2008-06-26
THE AEROSPACE CORPORATION
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

The power spectra density of the communicated channel signal is spread over the channel bandwidth and is difficult to acquire without advance knowledge of the spreading code.
Signal components of a channel signal are spread over the channel bandwidth providing low power components across the bandwidth rendering the isolation and reception of the input signal difficult without advance knowledge of the spreading code for correlation with the channel signal of interest.
In the event the replica code has a large code phase differential, coherently code phase lock is lost, and the signal cannot be reconstituted nor detected.

Method used

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  • Dual code spread spectrum communication system
  • Dual code spread spectrum communication system

Examples

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Embodiment Construction

[0013]An embodiment of the invention is described with reference to the figures using reference designations as shown in the figures. Referring to FIG. 1, a data source 10 provides messages in the form of sequence of data bits that are spectrum spread by a code spreader 12. A code generator 14 generates an original spreading code A during a first time period when the data source is providing a first message in the form of a first sequence of data bits, and, the code generator 14 generates an original spreading code B during a second time period when the data source 10 provides a second message in the form of a second sequence of data bits. The code spreader 12 spectrum spreads the first sequence of data bits that then modulates a carrier by the transmitter 16 that then broadcasts the first channel signal. The code spreader 12 spectrum spreads the second sequence of data bits that then modulates a carrier by the transmitter 16 that then broadcasts the second channel signal. Modulatio...

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Abstract

A direct sequence spread spectrum receiver includes a first spreading code generator for receiving a first channel signal spectrum spread by a first spread code, while a second group of receivers use a second spreading code, where the first and second codes are partially correlated, so that, the first group of receivers receive all messages communicated while the second group of receivers only receives a portion of the messages. In this manner, a spread spectrum broadcast system can selectively communicate to a selected portion of receivers in a whole group of receivers by simply switching the spreading code at the transmitter.

Description

STATEMENT OF GOVERNMENT INTEREST[0001]The invention was made with Government support under contract No. F04701-00-C-0009 by the Department of the Air Force. The Government has certain rights in the invention.FIELD OF THE INVENTION[0002]The invention relates to the field of direct sequence spectrum spreading (DSSS) communications systems. More particularly, the present invention relates to DSSS communications for selectively communicating from a transmitter to a select portion of a group of receivers using switched spreading codes.BACKGROUND OF THE INVENTION[0003]Spread spectrum communication systems use direct sequence spread spectrum (DSSS) codes for spectrum spreading channel signals communicated over respective communication channels and over a common channel bandwidth. Prior to transmission, an input signal having a narrow frequency spectrum, is spectrum spread by mixing the input signal with the DSSS code for providing a spread spectrum channel signal that has a spread spectrum...

Claims

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Application Information

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Patent Type & Authority Applications(United States)
IPC IPC(8): H04B1/00
CPCH04B1/707H04J13/0077H04J13/00
Inventor LILLO, WALTER E.
Owner THE AEROSPACE CORPORATION
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