# US 7,412,018 B1 · Rapid acquisition synchronization sequences for direct sequence spread spectrum systems using code time offsets

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- Number: US 7,412,018 B1
- Document ID: US7412018B1
- Status: Granted
- Kind: B1
- Application number: 09/573,218
- Filed: 2000-05-19
- Granted: 2008-08-12
- Earliest claimed: 1999-05-26
- Assignees: Alcatel USA Sourcing, L.P.
- Inventors: Francis D. Natali; John E. Ohlson
- Web page: https://patentgrep.com/patent/US7412018B1

## CPC

- H04J 13/0022: {PN, e.g. Kronecker}
- H04B 1/7075: with code phase acquisition
- H04J: MULTIPLEX COMMUNICATION (transmission in general H04B; peculiar to transmission of digital information H04L5/00; systems for the simultaneous or sequential transmission of more than one television signal H04N7/08; in exchanges H04Q11/00; stereophonic systems H04S)
- H04B: TRANSMISSION

## Abstract

In a wireless communication system which includes a synchronization signal generator which generates a synchronization sequence, an RF transmitter which transmits the synchronization signal, and one or more receiver that receives the signal, where the synchronization sequence employs M PN codes of the same length that are repeated in a pseudo-random fashion for N code periods. Each receiver incorporates M filters matched to the M PN codes whose outputs are post detection combined in a manner consistent with the pseudo-random code transmission sequence to provide signal detection and synchronization. In another aspect, the synchronization sequence employs M time-shifted versions of a PN code that are repeated in a pseudo-random fashion for N code periods and each receiver incorporates a filter matched to the unshifted PN code and whose output samples are post detection combined in a manner consistent with the pseudo-random code transmission sequence to provide signal detection and synchronization.

## Claims

### Claim 1

A wireless direct sequence spread spectrum communication system which includes a synchronization signal generator which generates a synchronization signal sequence, an RF transmitter which transmits the synchronization signal sequence, and one or more receiver that receives the signal, where:
said synchronization signal generator generates a synchronization signal sequence employs M time-shifted versions of a PN code that are cyclically repeated in a pseudo-random fashion for N code periods, and wherein each receiver incorporates a filter matched to the unshifted PN code and whose output samples are post detection combined in a manner consistent with the pseudo-random code transmission synchronization signal sequence to provide signal detection and synchronization.