Unlock instant, AI-driven research and patent intelligence for your innovation.

Optical OFDM transmission having a variable transmission rate

A technology of transmission rate and transmission power, which is applied in the field of optical OFDM transmission with variable transmission rate, and can solve the problem of reducing the maximum transmission distance

Inactive Publication Date: 2012-09-05
ALCATEL LUCENT SAS
View PDF4 Cites 5 Cited by
  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

As a result, the maximum transmission distance is reduced

Method used

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
View more

Image

Smart Image Click on the blue labels to locate them in the text.
Viewing Examples
Smart Image
  • Optical OFDM transmission having a variable transmission rate
  • Optical OFDM transmission having a variable transmission rate
  • Optical OFDM transmission having a variable transmission rate

Examples

Experimental program
Comparison scheme
Effect test

Embodiment Construction

[0062] about figure 1 Schematically explaining the operation of the optical OFDM transmitter. The digital data stream z[n], which may also include speech data, is supplied to a divider or demultiplexer 10 which divides the digital stream into a number of consecutive OFDM symbols. Each OFDM symbol consists of multiple words W 0 -W N-1 , where each word consists of at least one bit. every word W 0 -W N-1 is sent to the constellation modulator 12. Each constellation modulator transforms the word into a signal space constellation by applying a digital modulation scheme such as ASK, PSK, QPSK, MPSK and QAM. Each constellation modulator 12 may use a different form of digital modulation or all constellation modulators 12 may use the same form of digital modulation.

[0063] Constellation DataX 0 -X N-1 is supplied to a mapping unit 14 comprising an inverse Fourier transform unit. The mapping unit 14 transforms the constellation data X by using an inverse Fourier transform u...

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

PUM

No PUM Login to View More

Abstract

The present invention provides a method and a system for transmitting data over an optical channel using OFDM with a variable transmission rate. Such a method and a system feed an essentially constant transmission power over a predetermined OFDM bandwidth into the optical channel. In an embodiment, at least two OFDM subcarriers may be modulated with signal information derived from a single word of an OFDM symbol. Further thereto, the frequency spacing between the transmitted OFDM subcarriers may be changed.

Description

technical field [0001] The present invention relates to optical OFDM transmission methods and systems with variable transmission rates. Background technique [0002] OFDM (Orthogonal Frequency Division Modulation) is widely used in both wired and wireless communications. Examples of OFDM-based communication systems include DSL and WLAN according to IEEE 802.11G. [0003] In OFDM systems, the digital stream to be transmitted is divided into data words grouped into OFDM symbols. Each OFDM symbol includes multiple subcarriers. Each OFDM subcarrier is modulated by a word consisting of at least one bit. OFDM subcarriers may be modulated, for example, by BPSK, QPSK, 16-QAM or 64-QAM modulation schemes. OFDM subcarriers are orthogonal to each other. Orthogonality within an OFDM context is defined as an OFDM subcarrier having its maximum value at a frequency where the magnitude of adjacent OFDM subcarriers is zero. Therefore, the distortion between subcarriers will be signific...

Claims

the structure of the environmentally friendly knitted fabric provided by the present invention; figure 2 Flow chart of the yarn wrapping machine for environmentally friendly knitted fabrics and storage devices; image 3 Is the parameter map of the yarn covering machine
Login to View More

Application Information

Patent Timeline
no application Login to View More
Patent Type & Authority Applications(China)
IPC IPC(8): H04B10/155H04B10/18H04L27/26H04L5/00H04B10/255H04B10/516
CPCH04B10/255H04L1/08H04L5/0007H04L5/0044H04L5/0087H04L25/03866H04B10/548H04L27/2634H04L27/26524H04B10/00H04L27/26
Inventor F·布哈利A·克勒坎普
Owner ALCATEL LUCENT SAS