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Channel estimation method for PDM-CO-OFDM (Pulse Duration Modulation-Coherent Optical-Orthogonal Frequency Division Multiplexing) system

A technology of PDM-CO-OFDM and channel estimation, which is applied in the field of multi-frequency code system, and can solve the problems of increased calculation amount and increased system overhead

Inactive Publication Date: 2013-01-09
HEBEI UNIV OF TECH
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Problems solved by technology

[0004] The technical problem to be solved by the present invention is to provide a channel estimation method for a PDM-CO-OFDM system, which is a channel estimation method based on scattered pilots combined with multi-wavelet and frequency-domain average within symbols for joint noise reduction, overcoming Eliminates the defects of increased calculation and increased system overhead of related existing OFDM channel estimation methods

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  • Channel estimation method for PDM-CO-OFDM (Pulse Duration Modulation-Coherent Optical-Orthogonal Frequency Division Multiplexing) system
  • Channel estimation method for PDM-CO-OFDM (Pulse Duration Modulation-Coherent Optical-Orthogonal Frequency Division Multiplexing) system
  • Channel estimation method for PDM-CO-OFDM (Pulse Duration Modulation-Coherent Optical-Orthogonal Frequency Division Multiplexing) system

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Embodiment

[0071] In the optical OFDM system, block pilots or comb pilots are used in the prior art, and these two pilots have better estimation performance, but the system overhead is relatively large. The scattered pilot used in the present invention can perform channel estimation and phase noise compensation while reducing system overhead.

[0072] The first step is to design and select the scattered pilot format at the sending end of the PDM-CO-OFDM system, and send information data and pilot data

[0073] Through multiple simulation experiments, considering both system overhead and estimated performance, the S f = 6, S t1 = 4 and S t2 =3, it is the optimal scattered pilot pattern. image 3 and Figure 4 Shown are the scattered pilot patterns for the X and Y polarization directions used in this embodiment. The pilots have the same insertion interval in the frequency domain and the same insertion interval in the time domain, but the insertion method is the same for every other OF...

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Abstract

The invention provides a channel estimation method for a PDM-CO-OFDM (Pulse Duration Modulation-Coherent Optical-Orthogonal Frequency Division Multiplexing) system and relates to a system applying a multi-frequency code in a transmission process of digital information. The channel estimation method comprises the following steps of: designing and selecting a discrete guide frequency format at a sending end of the PDM-CO-OFDM system; sending information data and guide frequency data; utilizing a least square algorithm, namely an LS (Least Algorithm) algorithm, to carry out guide frequency point channel estimation on an orthogonal frequency division multiplexing mark by the information data and the guide frequency data received by a receiving end; carrying out linear interpolation on a frequency region and carrying out multi-wavelet de-noising on an obtained interpolation value; carrying out the linear interpolation on a time region; carrying out mark inner frequency averaging on an interpolation value result to finish combined de-noising; carrying out matrix inversion algorithm on a channel property subjected to the de-noising treatment; and finally, estimating sending data. According to the channel estimation method, based on a discrete guide frequency, the average combined de-noising of a multi-wavelet and a mark inner frequency region is used for carrying out channel estimation, so that defects that the calculation amount of the relative conventional OFDM channel estimation method is increased and the system expenditure is increased are overcome.

Description

technical field [0001] The technical scheme of the present invention relates to a system using multi-frequency codes in the transmission of digital information, specifically a channel estimation method for PDM-CO-OFDM systems. Background technique [0002] At present, people's demand for communication capacity increases sharply, and the research of high-speed optical fiber communication system has attracted people's great attention. The evolution of ultra-large-capacity optical fiber transmission network has become one of the future mainstream development directions in the current international communication field. Polarization multiplexing coherent optical orthogonal frequency division multiplexing system, that is, PDM-CO-OFDM system, is recognized as a high-speed long-distance optical signal due to its high speed, high spectrum efficiency, high receiving sensitivity and strong anti-multipath ability. A solution for transmission. However, due to the time-varying nature of...

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Application Information

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IPC IPC(8): H04L27/26H04L25/02
Inventor 刘剑飞李洁曾祥烨王蒙军
Owner HEBEI UNIV OF TECH
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