Multiple-rate direct sequence architecture utilizing a fixed chipping rate and variable spreading code lengths
US5946344A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Apr 7, 1997 |
| Grant date | Aug 31, 1999 |
| Priority date | — |
| Expiry date | Apr 7, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B1/7093
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A spread spectrum communication system is provided in which a receiver is adapted to despread multi-bit digital signals transmitted with a fixed chipping rate using two or more different spreading code lengths. As a result, a longer spreading code could be utilized to transmit at a lower data rate for conditions in which jamming resistance is more critical, such as over longer distances, and a shorter spreading code could be utilized to transmit at a higher data rate for conditions in which jamming resistance is less critical, such as over shorter distances. The receiver further comprises a digital matched filter adapted to correlate to the two different spreading codes. The digital matched filter comprises a digital delay line having a plurality of successive delay stages that propagate the received digital signal therethrough at a fixed rate corresponding to the chipping rate of the digital signal. A first correlator compares the digital signal to a first spreading code having a length M, and a second correlator compares the digital signal to a second spreading code having a length N, in which N is less than M. A multiplexer is adapted to select an output from one of the two corr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.