Combined frequency offset tracking and channel equalization method and realization system

A channel equalization and pilot channel technology, applied in multi-frequency code systems and other directions, can solve problems such as difficulty in quickly and accurately estimating channel response and reduced system transmission performance.

CN1968242AActive Publication Date: 2007-05-23ZHEJIANG UNIV +1
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2007-05-23

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Abstract

The invention relates to a frequency shift tracking and channel balance method used in OFDM system, wherein it comprises that; evaluating out channel response initial value Hn, Ki at each pilot position of OFDM data mark converted to the frequency domain; weighting and summing the Hn and Ki, with H'n-1 and Ki at last OFDM data mark, asme pilot position, which has been corrected frequency bias, to obtain the Hn and Ki at present pilot with weighted, smoothed and filtered; interpolating the channel evaluate value at all pilots, to obtain the channel response evaluate values Hn and K of all sub carrier values; removing the receive value of all sub carrier values of present mark from the channel evaluate value of all sub carrier waves, to complete channel balance. The invention has eliminated the channel evaluate result change caused by left frequency bias, to reach accurate result.
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Description

technical field

[0001] The present invention relates to an Orthogonal Frequency Division Multiplexing (OFDM) system, in particular to a joint method of frequency offset tracking and channel equalization and an implementation system. Background technique

[0002] Orthogonal Frequency Division Multiplexing (OFDM) transmission system not only has high spectral efficiency, but also can effectively deal with frequency selective fading, and is very suitable for broadband transmission, so it is widely used in various wireless broadband communication systems. Its main weakness is that it is sensitive to carrier frequency offset, so OFDM receivers need to take various measures to eliminate frequency offset, including capturing and tracking frequency offset by using preamble and pilot frequency. At the same time, in order to deal with the multipath fading in the wireless channel, the OFDM receiver must also perform proper channel estimation and equalization. Therefore, frequency offs...

Examples

Embodiment Construction

[0097] For the convenience of description, the present invention introduces the following symbols:

[0098] N: number of OFDM modulated subcarriers;

[0099] k i : The subcarrier number of the i-th pilot component, 0≤k i ≤N-1, where i=1, 2, ..., p, p is the number of pilots;

[0100] P n，ki : The transmitted value of the i-th pilot component of the n-th symbol is a known quantity;

[0101] P n，ki : the actual received value of the ith pilot component of the nth symbol;

[0102] h n，ki : The channel response at the i-th pilot position of the initially estimated n-th symbol;

[0103] H' n，ki : The channel response at the i-th pilot position of the n-th symbol after frequency offset correction;

[0104] The channel response at the i-th pilot position of the n-th symbol after weighted smoothing filtering of the front and rear symbols;

[0105] The channel response at the kth subcarrier position of the nth symbol obtained after interpolation.

[0106] The combined me...