Bulk filtering and demodulation of independent FDMA sources
US6064645A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Dec 22, 1997 |
| Grant date | May 16, 2000 |
| Priority date | — |
| Expiry date | Dec 22, 2017 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/023
- WIPO fieldTelecommunications
- WIPO sectorElectrical engineering
Abstract
A satellite communications technique is disclosed that synchronizes the reception of numerous OFDM uplink signals (108, 110) at a satellite (106) receiver and bulk processes them in the satellite (106). In operation, the satellite (106) receives an OFDM uplink signal (110) transmitted by a CPE (104). The satellite 106 then compares the reception timing of the symbols in the received OFDM uplink signal (110) with a satellite timing reference, and generates a timing correction. The satellite (106) provides a downlink symbol clock as inherent structure in a downlink beam to the CPE (104) and also transmits the timing correction in the downlink beam. The CPE (104) uses the downlink symbol clock in conjunction with the timing correction to generate an uplink clock. The CPE (104) then transmits data in the OFDM uplink signal (110) synchronously with the uplink clock. Each CPE (102, 104) may be synchronized in this manner. In addition, the satellite (106) may also periodically re-compare the reception timing of the OFDM uplink signals (108, 110) with the satellite timing reference to generate new timing corrections, if necessary, for the CPEs (102, 104).
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.