Receiver for use in a code shift keying spread spectrum communications system
US6671311B1 · kind B1 · utility
Assignee
Inventors
Key dates
| Filing date | Apr 18, 2000 |
| Grant date | Dec 30, 2003 |
| Priority date | — |
| Expiry date | Apr 18, 2020 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04B2201/70703
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A direct sequence spread spectrum receiver for use in a communication system that utilizes code shift keying (CSK) modulation. Code shift keying modulation transmits data in the form of circularly rotated spreading waveforms such as PN sequences. The data is conveyed in the amount of rotation applied to the spreading waveform before it is transmitted. While tracking, the receiver decodes the received symbols yielding the original transmitted data. The input frequency range of the receiver is divided into one or more frequency bands. For each frequency band, the received signal is filtered, digitized and split into I and Q data streams wherein the Q data stream is delayed by ¼ƒc. Both I and Q data streams are sampled and correlated with an adaptive template. The received data is clocked into a shift register and circularly rotated and a correlation sum is generated. The correlation output of both I and Q channels are summed over all the frequency bands and a maximum correlations is determined. A shift index is chosen corresponding to the shift index yielding the maximum correlation sum. The templated in the receiver is dynamically adapted to the varying conditions of the…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.