EP0715440A1
Expired / Lapsed
EP
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Synchronous detector and synchronizing method for digital communication receiver
Assignee: NTT Docomo Inc
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Filing: 1995-06-21
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Granted: —
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Expires: 2015-06-21
Abstract
Abstract A synchronous detecting method in which the transfer function of a propagation path is estimated by regarding the information symbols adjacent to pilot signals as known symbols and using the information symbols as pseudo-pilot signals. The method includes a step of estimating the transfer function by using the pilot signals, a step of performing interpolation synchronous detection of part of the information symbols by using the estimated transfer function, a step of storing the result of the interpolation synchronous detection as pseudo-pilot signals, a step of reestimating the transfer function related to information symbols corresponding to the pseudo-pilot signals from the pseudo-pilot signals and the received signals corresponding to the pseudo-pilot signal, regarding the pseudo-pilots as known correct signals, and a step of performing interpolation synchronous detection of each information symbol by using the reestimated transfer function. Thus, the detection characteristic can be improved by estimating the transfer function with high accuracy even when the number of symbols per pilot signal is small.
Inventors
- 👤 Akihiro Higashi
- 👤 Fumiyuki Adachi
- 👤 Koji Ohno
- 👤 Mamoru Sawahashi
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-31 17:06
CPC Classifications
H; H04; H04L; H04L25/00; H04L25/02; H04L25/0202; H04L25/0224; H04L25/0228; H04L25/023; H04L25/0236; H04L25/0212; H04L25/0232; H04L7/00; H04L7/04; H04L7/08
Claims Analysis
Total Claims: 6
Claim 1
Independent Claim
277 words
A coherent detector for a digital communication receiver, which performs coherent detection of a received signal including pilot signals of a known pattern and information signals, by estimating for individual information symbols of said information signals transfer functions of a propagation path of said received signal on the basis of said pilot signals, by correcting said information symbols with estimated transfer functions, and by deciding corrected information symbols, each of said pilot signals alternating with each one of said information signals at a fixed period, said coherent detector characterized by comprising: a received signal memory for storing said received signal; pilot signal generating means for generating said pilot signals of said known pattern; transfer function estimation means for estimating said transfer functions using said pilot signals stored in said received signal memory and said pilot signals of said known pattern supplied from said pilot signal generating means; interpolation means for interpolating a plurality of transfer functions estimated by said transfer function estimation means, thereby obtaining said transfer functions for said information symbols; compensation means for compensating information symbols stored in said received memory by using said transfer functions obtained by said interpolation means; decision means for deciding said information symbols compensated by said compensation means; and pseudo-pilot signal storing means for storing a predetermined number of information symbols which are outputted from said decision means and adjacent to said pilot signals as pseudo-pilot signals, wherein said transfer function estimation means reestimates for individual information symbols corresponding to said pseudo-pilot symbols said transfer functions of said propagation path by using said pseudo-pilot signals and said information symbols in said received signal memory which correspond to said pseudo-pilot signals.
Claim 2
Dependent Claim
69 words
The coherent detector for a digital communication receiver as claimed in claim 1, characterized in that said transfer function estimation means further comprises: means for estimating a fading frequency from said pilot signals; and means for prestoring relationships between forgetting factors and estimation errors of said transfer functions with said fading frequency as a parameter, wherein one of said forgetting factors which will minimize said estimation errors is selected.
Claim 3
Dependent Claim
221 words
A coherent detection method for a digital communication receiver, which performs coherent detection of a received signal including pilot signals of a known pattern and information signals, by estimating for individual information symbols of said information signals transfer functions of a propagation path of said received signal on the basis of said pilot signals, by correcting said information symbols with estimated transfer functions, and by deciding corrected information symbols, each of said pilot signals alternating with each one of said information signals at a fixed period, said coherent detection method characterized by comprising the steps of: storing said received signal; generating said pilot signals of said known pattern; estimating said transfer functions using said pilot signals stored and said pilot signals of said known pattern; interpolating a plurality of transfer functions estimated, thereby obtaining said transfer functions for said information symbols; compensating information symbols by using said transfer functions obtained in said step of interpolating; deciding said information symbols compensated; storing a predetermined number of information symbols which are decided in said step of deciding and adjacent to said pilot signals as pseudo-pilot signals; and reestimating for individual information symbols corresponding to said pseudo-pilot symbols said transfer functions of said propagation path by using said pseudo-pilot signals and said information symbols in said received signal which correspond to said pseudo-pilot signals.
Claim 4
Dependent Claim
61 words
The coherent detection means for a digital communication receiver as claimed in claim 3, further characterized by comprising the steps of: estimating a fading frequency from said pilot signals; prestoring relationships between forgetting factors and estimation errors of said transfer functions with said fading frequency as a parameter; and selecting one of said forgetting factors which will minimize said estimation errors.
Claim 5
Dependent Claim
277 words
A digital communication receiver including a coherent detector which performs coherent detection of a received signal including pilot signals of a known pattern and information signals, by estimating for individual information symbols of said information signals transfer functions of a propagation path of said received signal on the basis of said pilot signals, by correcting said information symbols with estimated transfer functions, and by deciding corrected information symbols, each of said pilot signals alternating with each one of said information signals at a fixed period, said coherent detector characterized by comprising: a received signal memory for storing said received signal; pilot signal generating means for generating said pilot signals of said known pattern; transfer function estimation means for estimating said transfer functions using said pilot signals stored in said received signal memory and said pilot signals of said known pattern supplied from said pilot signal generating means; interpolation means for interpolating a plurality of transfer functions estimated by said transfer function estimation means, thereby obtaining said transfer functions for said information symbols; compensation means for compensating information symbols stored in said received memory by using said transfer functions obtained by said interpolation means; decision means for deciding said information symbols compensated by said compensation means; and pseudo-pilot signal storing means for storing a predetermined number of information symbols which are outputted from said decision means and adjacent to said pilot signals as pseudo-pilot signals, wherein said transfer function estimation means reestimates for individual information symbols corresponding to said pseudo-pilot symbols said transfer functions of said propagation path by using said pseudo-pilot signals and said information symbols in said received signal memory which correspond to said pseudo-pilot signals.
Claim 6
Dependent Claim
65 words
The digital communication receiver as claimed in claim 5, characterized in that said transfer function estimation means further comprises: means for estimating a fading frequency from said pilot signals; and means for prestoring relationships between forgetting factors and estimation errors of said transfer functions with said fading frequency as a parameter, wherein one of said forgetting factors which will minimize said estimation errors is selected.
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