Optical Orthogonal Frequency Division Multiplexing Transmission with Improved Efficiency

A technology of frequency band and dispersive light, applied in the field of optical communication

Inactive Publication Date: 2011-11-30
OFIDIUM PTY LTD
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

As noted above, this is incompatible with using longer symbols to reduce overhead due to the required guard interval

Method used

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  • Optical Orthogonal Frequency Division Multiplexing Transmission with Improved Efficiency
  • Optical Orthogonal Frequency Division Multiplexing Transmission with Improved Efficiency
  • Optical Orthogonal Frequency Division Multiplexing Transmission with Improved Efficiency

Examples

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Embodiment Construction

[0037] Fig. 1 schematically shows a system 100 for transmitting digital information through a dispersive optical channel according to a preferred embodiment of the present invention. Exemplary system 100 includes a sending device 102 and a receiving device 104, which are generally referred to herein as a "transmitter" and a "receiver," respectively, for convenience.

[0038] Transmitter 102 communicates with receiver 104 via optical channel 106, which typically exhibits linear optical dispersion including chromatic dispersion and polarization mode dispersion. Optical channel 106 may also exhibit non-linear transmission characteristics. Although embodiments of the present invention may be employed in systems that also incorporate nonlinear compensation methods, such as the system disclosed in International Application Publication No. WO 2008 / 075085, the present invention is primarily concerned with improving the response to linear degree dispersion) compensation processing.

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Abstract

A method of transmitting digital information over a dispersive optical channel (106) comprises encoding (152) the digital information into a series of data blocks, wherein each block comprises a plurality of substantially orthogonal frequency domain subcarriers, each data block is then divided (154) into at least two frequency bands, each band comprising a plurality of contiguous subcarriers. A frequency / time transformation is then performed (156), in order to form a corresponding plurality of transformed bands, each transformed band comprising a sequence of time domain data samples. A time delay is applied (158) to at least one of the transformed bands relative to at least one other of the transformed bands. The bands are then combined (160) to produce an electrical signal waveform embodying the digital information. Finally, an optical source is modulated (162) using the electrical signal waveform, to produce a corresponding optical signal for transmission over the dispersive optical channel (106). The invention enables a reduction in the duration of guard intervals that may need to be inserted into the transmitted data blocks, in order to avoid received signal degradation due to inter-symbol interference caused by dispersion in the optical channel (106). Transmission overheads may thereby be reduced, resulting in an improvement in transmission efficiency.

Description

technical field [0001] The present invention relates generally to optical communications and, more particularly, to improvements in the efficiency of optical transmission systems utilizing Orthogonal Frequency Division Multiplexing (OFDM) and related techniques to mitigate problems such as chromatic dispersion ( chromatic dispersion) transmission damage. Background technique [0002] Orthogonal Frequency Division Multiplexing (OFDM) is a scheme for transmitting digital data using a large number of closely spaced orthogonal subcarriers. In particular, digital information is efficiently encoded into several parallel data streams or channels, each assigned to a subcarrier. The information is modulated onto subcarriers using conventional modulation schemes such as quadrature amplitude modulation (QAM) or phase shift keying (PSK) at a symbol rate that is low relative to the overall data transmission rate. The total transmission capacity of OFDM systems is usually comparable to ...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B10/04H04L27/18H04B10/2513H04B10/516
CPCH04L5/0044H04L5/0007H04B10/548H04B10/25137H04B10/516H04B2210/254
Inventor 阿瑟・詹姆斯・洛厄里
Owner OFIDIUM PTY LTD
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