Modulation and demodulation apparatuses and methods for wired/wireless communication system
US7961798B2 · kind B2 · utility
Assignee
Inventor
Key dates
| Filing date | Nov 30, 2006 |
| Grant date | Jun 14, 2011 |
| Priority date | — |
| Expiry date | Mar 1, 2028 |
Classification
- Technology area (CPC H)Electricity
- CPC primaryH04L5/0044
- WIPO fieldDigital communication
- WIPO sectorElectrical engineering
Abstract
Wired/wireless optical signal modulation and demodulation apparatuses and methods using an intensity modulation/direct detection method and an orthogonal frequency division multiplexing (OFDM) method are provided. A unipolar OFDM symbol frame is generated by determining the polarity of each of a plurality of sub-frames of a bipolar OFDM symbol frame which comprises both a plurality of positive pulses and a plurality of negative pulses, inverting the polarity of the sub-frames which are determined to be negative, delaying one of the positive sub-frame and a positive sub-frame obtained through the inversion by the duration of the sub-frames, and multiplexing the result of the delaying and whichever of the positive sub-frame and the positive sub-frame obtained through the inversion is not the result of the delaying. The unipolar OFDM symbol frame can guarantee high power amplification efficiency and high transmission power efficiency, and is robust against a multi-path channel environment. Therefore, the unipolar OFDM symbol frame can be used in various optical signal modulation/demodulation methods for wireless indoor broadband optical transmission devices, wired broadband optical tr…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.