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Channel estimation method based on comb-type pilot frequency for DDO-OFDM system

A DDO-OFDM, comb pilot technology, applied in the field of optical communication, can solve the problems of low precision and low spectrum utilization, and achieve the effects of improving signal-to-noise ratio gain, reducing bit error rate, and improving frequency band utilization.

Active Publication Date: 2016-03-23
HANGZHOU DIANZI UNIV
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Problems solved by technology

[0008] In order to overcome the shortcomings of traditional channel estimation methods such as low frequency spectrum utilization and low precision, the present invention proposes a new channel estimation method based on comb-shaped pilots for DDO-OFDM systems

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  • Channel estimation method based on comb-type pilot frequency for DDO-OFDM system
  • Channel estimation method based on comb-type pilot frequency for DDO-OFDM system
  • Channel estimation method based on comb-type pilot frequency for DDO-OFDM system

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Embodiment

[0069] Such as Figure 4 As shown, it is a comparison chart of the pre-experimental noise ratio-SNR between the LS estimation averaging method based on block pilots in this embodiment and the LS channel estimation method based on comb pilots in the present invention. It sets O-OFDM to transmit 1023 OFDM symbols, including 1024 carriers (the first line does not contain data, that is, the effective subcarriers start from the second to the 1024th, that is to say, the actual number of effective subcarriers is 1023 ), the pilot expense is 1 / 512. Utilize the method of the present invention as follows:

[0070] (1) The pilot cost is 1 / 512, that is, the pilot interval L is 511, then there are 3 pilot subcarriers, which are the 2nd, 513th, and 1024th subcarriers respectively, and the pilot vector is denoted as X 3 .

[0071] x 3 =[X(2,:);X(513,:);X(1024,:)] 3×M

[0072] The first subcarrier does not contain data, and the remaining subcarriers are all data subcarriers.

[0073] (...

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Abstract

The present invention discloses a channel estimation method based on comb-type pilot frequency for a DDO-OFDM system. The method comprises the steps of (1) obtaining a pilot frequency position, (2) inserting a pilot frequency subcarrier at the frequency pilot position in the sending signal of an emitting end, (3) extracting the pilot frequency subcarrier for a receiving signal at a same pilot frequency position at a receiving end, (4) using LS estimation average method to estimate the average frequency response of the pilot frequency subcarrier, and (5) using a linear interpolation method to estimate the frequency response of the data subcarrier in a channel. In the same pilot frequency expenditure, the error rate is reduced by the algorithm of the present invention, the estimation accuracy is raised, and the SNR gain is raised. The pilot frequency expenditure influence on the algorithm error rate is small, the low error rate can be ensured even in small pilot frequency expenditure, the frequency band utilization rate is raised, the complexity of the algorithm is low, and the practicability is high.

Description

technical field [0001] The invention belongs to the technical field of optical communication, in particular to a comb pilot-based channel estimation method used in a DDO-OFDM system. Background technique [0002] With the development of communication technology and the continuous improvement of communication requirements, optical communication shows two obvious development trends: the data rate of single-channel transmission is greatly increased, approaching 100Gb / s; the network must have fast dynamic adjustment capabilities . However, when the data rate reaches 100Gb / s, the traditional optical fiber segment compensation becomes expensive and time-consuming, and it is difficult to accurately realize the compensation for system dispersion. However, due to its good calculation characteristics, OFDM can perform complex operations in the frequency domain. The fiber dispersion can be easily compensated. Specific references: SHIEHW, BAOH, TANGY. Coherent Optical OFDM: Theory and...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04L25/02
CPCH04L25/024H04L27/2601H04L27/2695
Inventor 李洁炜毕美华杨国伟郑坤卓怡琳黄天成牟小华
Owner HANGZHOU DIANZI UNIV
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