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Frequency domain channel estimation method of crossing frequency division multiplexing system with time-domain enveloping weighting

An orthogonal frequency division, frequency domain channel technology, applied in the field of frequency domain interpolation and frequency domain noise filtering channel estimation, can solve the problem of no noise, large channel frequency domain estimation error, traditional transform domain or linear interpolation algorithm can not meet the System requirements and other issues to achieve the effect of improving performance and improving estimation performance

Inactive Publication Date: 2007-02-07
TSINGHUA UNIV +1
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  • Abstract
  • Description
  • Claims
  • Application Information

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Problems solved by technology

For linear and transform domain interpolation algorithms, only interpolation is done, and there is no further suppression of noise in the frequency domain
[0005] Within the range of the actual OFDM system operating point, the channel frequency domain estimation error is too large, and the traditional transform domain or linear interpolation algorithm cannot meet the system requirements

Method used

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  • Frequency domain channel estimation method of crossing frequency division multiplexing system with time-domain enveloping weighting
  • Frequency domain channel estimation method of crossing frequency division multiplexing system with time-domain enveloping weighting
  • Frequency domain channel estimation method of crossing frequency division multiplexing system with time-domain enveloping weighting

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Embodiment Construction

[0035] Below in conjunction with accompanying drawing and example, the present invention is described in detail:

[0036] In this embodiment, the transceiver adopts the Orthogonal Frequency Division Multiplexing OFDM technology for communication. One OFDM symbol length NFFT points, pilot insertion interval Finterval points, the number of non-negative pilot subcarriers NonnegaPilot points, the number of pilot positions in virtual subcarrier points VSCPilot points, the number of negative pilot subcarriers NegaPilot points , the time domain cyclic prefix length CP point, the first non-negative pilot subcarrier sequence number is InitPilot.

[0037] This embodiment only discusses the comb-shaped pilot insertion method, as shown in FIG. 1( b ). The transmitter implements as figure 2 shown.

[0038] For the convenience of description, we describe for the kth OFDM symbol, k=0, 1, 2, . . . .

[0039] a) Modulation mapping to obtain symbol M k (f), the modulation can adopt QPSK, 1...

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Abstract

The invention relates to a frequency interpolation method and a frequency domain noise filter method in OFDM mark, wherein it is characterized in that: based on single-receiving single-sending OFDM system, or the multi-sending multi-receiving system whose pilot positions are orthogonal, in the converted time domain sequence, enveloping and weighting to restrain the time domain noise, while the higher of enveloping value, the weighting factor is near to 1; or else, the weighting factor is near to 0; the invention provides the formula to calculate best envelop weighting factor; and it also provides a weighting factor calculation based on constant envelop weighting similar, threshold valve envelop similar and incline envelop weighting similar. The invention can improve the property of signal channel estimate after OFDM frequency domain interpolation.

Description

technical field [0001] The invention relates to a channel estimation method for frequency domain interpolation and frequency domain filtering noise in an OFDM symbol in an OFDM system using comb pilot symbols and mesh pilot. Background technique [0002] With the increasing bandwidth requirement in wireless communication, Orthogonal Frequency Division Multiplexing (OFDM) multi-carrier transmission system is attracting a lot of attention in recent years. [0003] Since the OFDM system uses technologies such as inverse Fourier transform and cyclic prefix at the transmitting end and uses Fourier transform demodulation after discarding the cyclic prefix at the receiving end, it eliminates intersymbol interference and converts frequency selective channels into flat fading Therefore, in practical applications, only a simple frequency domain equalization technique is required to allow high-speed data transmission. Of course, to obtain high performance, it is necessary to accuratel...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L25/02H04L27/06H04L25/08
Inventor 高群毅周世东
Owner TSINGHUA UNIV