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A Channel Estimation Method Based on Alternating Parity and Even Pilot Sequences in Navdat

A technology of pilot sequence and channel estimation, applied in baseband system components and other directions, can solve the problem of reducing the accuracy of channel estimation, and achieve the effect of improving accuracy

Active Publication Date: 2018-02-27
ZHEJIANG UNIV
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Problems solved by technology

On the contrary, the accuracy of channel estimation will decrease

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  • A Channel Estimation Method Based on Alternating Parity and Even Pilot Sequences in Navdat
  • A Channel Estimation Method Based on Alternating Parity and Even Pilot Sequences in Navdat
  • A Channel Estimation Method Based on Alternating Parity and Even Pilot Sequences in Navdat

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[0035] In order to make the technical solution and advantages of the present invention clearer, the specific implementation of the technical solution will be described in more detail in conjunction with the accompanying drawings:

[0036] The transmission of OFDM symbols can be regarded as a two-dimensional transmission structure of time domain and frequency domain. In the time domain, an OFDM symbol period is used as a unit, and in the frequency domain, a subcarrier is used as a unit. Considering this two-dimensional transmission characteristic, we can optionally insert pilot signals in the time-frequency domain array. In practical applications, considering the complexity of the receiver and the Doppler frequency offset is relatively large in the short-wave sky-wave channel environment, it is more suitable to use the comb-shaped pilot scheme in the sky-wave channel, such as figure 1 shown. In the figure, t represents the direction in the time domain, and f represents the dir...

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Abstract

The invention proposes a channel estimation method in NAVDAT based on an odd-even alternative pilot frequency sequence, and the method comprises the following steps: (1) inserting a pilot frequency sequence on the subcarrier of each OFDM symbol at equal intervals at an NAVDAT transmission end according to a specific rule; (2) employing the least square method to estimate a channel impulse response at a pilot frequency position at an NAVDAT receiving end; (3) estimating the channel impulse response of the odd number subcarrier of each OFDM symbol through linear interpolation algorithm; (4) estimating all channel impulse responses based on an interpolation algorithm of a low-pas filter. The method makes the most of channel characteristics of adjacent OFDM symbols to estimate the channel impulse response of the odd number subcarrier of each OFDM symbol. Compared with a mode of comb-shaped distribution pilot frequency insertion with the same pilot frequency interval, the method further improves the accuracy of channel estimation under the condition of not reducing the efficiency of data transmission.

Description

technical field [0001] The present invention relates to a pilot frequency design and channel estimation method of a wireless mobile digital communication system, especially relates to the use of odd and even alternating pilot sequences to improve frequency spectrum utilization and channel estimation accuracy in the case of long channel coherence time, an application Pilot design and channel estimation method in NAVDAT (Navigational Data, navigation data) digital communication system. Background technique [0002] The NAVDAT digital communication system is a digital broadcasting system that works in the 500KHz frequency band and is used for maritime mobile services to ensure maritime safety and secure transmission of relevant information from the shore to the ship. This digital communication system provides broadcast transmission services for various types of messages and is encrypted. The messages broadcast include but are not limited to navigation safety, information secur...

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Application Information

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Patent Type & Authority Patents(China)
IPC IPC(8): H04L25/02
Inventor 伍冲斌雷鸣赵民建赵明敏刘亚辉方应潘燕杰陈波
Owner ZHEJIANG UNIV
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