ACO-OFDM system channel estimation method based on compressed sensing

A compressed sensing and channel estimation technology, which is applied in the field of channel estimation of ACO-OFDM wireless optical communication systems based on compressed sensing, and can solve the problems that the compressed sensing channel estimation method cannot be directly applied and the research on the application of compressed sensing theory is insufficient.

Inactive Publication Date: 2017-06-30
CHONGQING UNIV OF POSTS & TELECOMM
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Problems solved by technology

[0006] Scholars at home and abroad have made some achievements in the research of OFDM channel estimation method based on compressed sensing, but the research on the application of compressed sensing theory in ACO-OFDM channel estimation is not enough
Due to the difference between ACO-OFDM and traditional OFDM systems, the compressed sensing channel estimation method suitable for traditional OFDM systems cannot be directly applied to ACO-OFDM systems

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  • ACO-OFDM system channel estimation method based on compressed sensing
  • ACO-OFDM system channel estimation method based on compressed sensing
  • ACO-OFDM system channel estimation method based on compressed sensing

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Embodiment Construction

[0014] The implementation of the present invention will be further described below in conjunction with the accompanying drawings.

[0015] The schematic diagram of ACO-OFDM system is as follows: figure 1 shown. The present invention adopts the comb pilot, in order to meet the requirements of the ACO-OFDM system, the pilot symbols need to have Hermitian symmetry and be inserted in odd subcarriers, with the following relationship:

[0016]

[0017] where N P is the number of pilots (·) * Indicates conjugation.

[0018] The measurement matrix in ACO-OFDM system channel estimation is composed of pilot symbols and DFT sub-matrix Composition, namely:

[0019]

[0020] in It is formed according to the N×NDFT matrix row and the first L columns corresponding to the pilot position, and L is the channel length. For the pilot position index, it should be noted that odd subcarriers correspond to even rows in the DFT matrix, because the number of carriers is calculated from ...

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Abstract

The present invention provides an ACO-OFDM wireless optical communication system channel estimation method based on compressed sensing, and belongs to the field of intensity modulation optical communication. The channel estimation method is used to solve the problem that during pilot based channel estimation, a pilot symbol causes a bandwidth utilization rate to be reduced. According to the method provided by the present invention, channel estimation technology based on the compressed sensing is combined with the ACO-OFDM system. Firstly, the pilot is enabled to have Hermitian symmetry, a pilot allocation scheme is optimized by minimizing a DFT sub-matrix cross-correlation squared sum, and an ACO-OFDM system pilot allocation optimization algorithm is provided. Then, a channel response is estimated by using an improved variable step sparse degree adaptive matching tracking algorithm, the improved algorithm can improve estimation accuracy and calculation speed. Finally, an iterative correction algorithm is used to further improve the estimation accuracy. Compared with the traditional pilot based channel estimation method, the method can effectively reduce the number of pilot symbols, and improve the system bandwidth utilization rate.

Description

technical field [0001] The invention belongs to the field of intensity modulation optical communication, in particular to a channel estimation method for an ACO-OFDM wireless optical communication system based on compressed sensing. Background technique [0002] Wireless optical communication has the advantages of free spectrum resources, huge available bandwidth, simple system equipment, small size, good confidentiality and no electromagnetic interference. The capacity and bandwidth requirements of communication systems are getting higher and higher, and wireless optical communication has shown its application value in communication systems, see the literature: "Boucouvalas A, Chatzimisios P, Ghassemlooy Z, et al.Standards for indoor Optical Wireless Communications[J ].IEEE Communications Magazine, 2015,53(3):24-31." The wireless optical OFDM proposed in the document "Gonzalez O, Perez-JimenezR, Rodriguez S, et al. OFDM over indoor wireless optical channel[J]. IEE Proceedi...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26
CPCH04L27/2695H04L27/2692
Inventor 赵辉张浩翀李红兵
Owner CHONGQING UNIV OF POSTS & TELECOMM
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