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Channel estimation by adaptive interpolation

An adaptive, channel technology, applied in channel estimation, transmission path sub-channel allocation, pilot signal allocation and other directions, which can solve problems such as large number of subcarriers, difficult interpolation, and complex filters.

Inactive Publication Date: 2006-12-20
OPTIS WIRELESS TECH LLC
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  • Summary
  • Abstract
  • Description
  • Claims
  • Application Information

AI Technical Summary

Problems solved by technology

Due to the fact that the number of subcarriers is large, the symbol period will also be large, which means that if the part of the symbol used as a pilot remains the same, the pilots will be farther apart in time and the interpolation becomes harder, requiring more complex filters
Furthermore, due to the large number of subcarriers, the amount of data that must be buffered for each OFDM will also be large

Method used

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  • Channel estimation by adaptive interpolation
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Embodiment Construction

[0045] In order to facilitate the understanding of the disclosed method and equipment, this specification is based on an example whose data is very similar to the parameters in DVB-T, the European Telecommunications Standards Institute (ETSI) EN 300 744V.1.4.1 (Jan.2001) Digital TV Broadcasting (DVB) The standard of terrestrial digital television broadcasting announced; the framing structure, channel coding and modulation of digital terrestrial television. Specifically, assume that the symbol rate R s It is 1K symbols / second, and the distance between different carriers is 1 kHz. For time interpolation, every fourth symbol is a pilot, and after interpolation is performed in the time direction, every third carrier is a pilot. In addition, let C / N represent the carrier-to-noise ratio or carrier-to-interference ratio, and let f D Represents the (maximum) Doppler frequency shift, and let T m Represents the (maximum) delay spread. Obviously, the present invention is not limited to DVB o...

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PUM

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Abstract

Methods and apparatus that achieve good channel estimation without using unnecessarily complex interpolation filters are described. Adaptive interpolation filtering of a signal in a receiver includes determining at least one correlation function parameter of the channel and determining a filter configuration based on the correlation function parameter. The interpolation may be performed in time, where a Doppler frequency shift can serve as the correlation function parameter, or in frequency, where a root mean square or maximum delay spread can serve as the correlation function parameter, or both. A worst case signal-to-noise ratio may be used in determining the filter configuration, or, optionally, the signal-to-noise ratio can be determined in real time. The filter configuration can be determined in real time or selected from one of a plurality of predetermined configurations having different complexities.

Description

Technical field [0001] This application relates to digital communication for channel estimation through pilot symbols. In particular, it relates to situations where it is desired to avoid or reduce high-order interpolation filters, because such filters require memory and are complicated. This application also relates to situations where it is desired to estimate the channel correlation function through a low-complexity method. Background technique [0002] In wireless communication, data to be communicated is usually transmitted via a channel whose characteristics change with time and frequency. That is, the amplitude and phase of the channel change from one symbol to the next symbol and from one frequency to the next frequency. The signal change between two symbols in time basically depends on two things, that is, how fast the symbol period and the actual channel change; but the channel change between the two frequencies depends on the frequency distance How far away and how the...

Claims

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Application Information

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IPC IPC(8): H04L25/02H04L27/26
CPCH04L27/2647H04L25/0234H04L25/022H04L5/0048H04L25/0222H04B1/12H04B1/40H04L27/38
Inventor L·威廉松L·安德松B·伯恩哈松
Owner OPTIS WIRELESS TECH LLC