EP1441484A2
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EP
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Reception and equalisation of multicarrier signals
Assignee: Toshiba Corp
•
Filing: 2004-01-21
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Granted: —
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Expires: 2024-01-21
Abstract
Abstract An apparatus for receiving an OFDM signal, including an AC and TMCC signals (2), a CP signal (3) and a SP signal (4), includes: an FFT circuit (15) configured to input the received OFDM signal and perform an FFT on the input OFDM signal based on an FFT window; an interpolation circuit (22) configured to interpolate the SP signal (4) outputted from theFFT circuit (15) ; an equalizer (26a) configuredtoequalize the AC and TMCC signals (2) and the CP signal (3), as the reference of the interpolated SP signal (4); an S/N ratio detector (27a) configured to detect an S/N ratio indicating a reception quality, based on an equalized output of the equalizer (26a); and an FFT window controller (28) configured to control a position of the FFT window as the position where the reception quality is the best condition based on the S/N ratio.
Inventors
- 👤 Takashi Seki
- 👤 Masahiko Sugimoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 00:32
CPC Classifications
H; H04; H04L; H04L27/00; H04L27/26; H04L27/2601; H04L27/2647; H04L27/2655; H04L27/2662; H04L27/2665; H04L25/00; H04L25/02; H04L25/0202; H04L25/021; H04L25/03; H04L25/03006; H04L25/03012; H04L2025/0335; H04L2025/03375; H04L2025/03414; H04L25/0224; H04L25/0228; H04L25/023; H04L25/0232; H04L5/00; H04L5/003; H04L5/0048
Claims Analysis
Total Claims: 10
Claim 1
Independent Claim
240 words
An apparatus for receiving an Orthogonal Frequency
Division Multiplex (OFDM) signal, the OFDM signal including
at least one signal selected from an additive information
signal (2) transmitted at a specific frequency and a continual
pilot signal (3) transmitted at a specific frequency, and
a scattered pilot signal (4) transmitted as scattered along
frequency and time axes, characterized by comprising: a fast Fourier transform circuit (15) configured to input
the received OFDM signal and perform a fast Fourier
transformation on the input OFDM signal based on an FFT window,
which specifies the range on a time-axis of the fast Fourier
transformation, in order to convert the time-axial data to
frequency-axial data; an interpolation circuit (22) configured to interpolate
the scattered pilot signal (4) outputted from the fast Fourier
transform circuit (15); an equalizer (26a) configured to equalize at least one
signal selected from the additive information signals (2)
and the continual pilot signal (3), as the reference of the
interpolated scattered pilot signal (4) outputted from the
interpolation circuit (22); a reception quality signal detector (27a) configured
to detect a reception quality signal indicating a reception
quality of the received OFDM signal, based on an equalized
output of the equalizer (26a); and an FFT window controller (28) configured to control a
position of the FFT window as the position where the reception
quality is the best condition, based on the reception quality
signal detected by the reception quality signal detector
(27a).
Claim 2
Dependent Claim
116 words
The apparatus of claim 1, characterized by further
comprising a differential detector (33a) configured to detect a
difference of a part of the additive information signals (2)
outputted from the fast Fourier transform circuit (15), and characterized in that : the equalizer (26b) equalizes at least one of the
additive information signals (2) except the differential
detection signal, which is used for the differential detection,
and the continual pilot signal (3), as the reference of the
interpolated scattered pilot signal (4) outputted from the
interpolation circuit (22); and the reception quality signal detector (27b) detects the
reception quality signal by using the equalized output of
the equalizer (26) and an output of the differential detector
(33a).
Claim 3
Dependent Claim
67 words
The apparatus of claim 1 or 2, characterized in
that the equalizer (26c) equalizes at least one of the
additive information signals (2) and the continual pilot
signal (3) the outputted from the fast Fourier transform
circuit (15), and the pilot signal (4) outputted from the
fast Fourier transform circuit (15), as the reference of the
interpolated scattered pilot signal (4) outputted from the
interpolation circuit (22).
Claim 4
Dependent Claim
61 words
The apparatus of claim 1, 2 or 3, characterized in
that the reception quality signal detector (27a) includes: a variance detector (31) configured to obtain respective
variance values from a predetermined reference signal point
for the respective equalized output of the equalizer (26a);
and an averaging circuit (32) configured to average the
obtained variance values and detect the reception quality
signal.
Claim 5
Dependent Claim
27 words
The apparatus of claim 1, 2, 3 or 4, characterized
in that the additive information signals (2) are modulated by
the differential Binary Phase Shift Keying method.
Claim 6
Dependent Claim
44 words
The apparatus of claim 2, characterized in that the differential detection signal from among the
additive information signals (2) is a transmission and
multiplexing configuration and control signal, and the
additive information signals (2) except the differential
detection signal is an auxiliary channel signal.
Claim 7
Independent Claim
184 words
A method of demodulation in an apparatus for
receiving an Orthogonal Frequency Division Multiplex (OFDM)
signal, the OFDM signal including at least one signal selected
from an additive information signal transmitted at a specific
frequency and a continual pilot signal transmitted at a
specific frequency, and a scattered pilot signal transmitted
as scattered along frequency and time axes, characterized
by comprising: inputting the received OFDM signal and performing a fast
Fourier transformation on the input OFDM signal based on an
FFT window, which specifies the range on a time-axis of the
fast Fourier transformation, in order to convert the
time-axial data to frequency-axial data; interpolating the scattered pilot signal performed by
the fast Fourier transformation; equalizing at least one signal selected from the additive
information signals and the continual pilot signal, as the
reference of the interpolated scattered pilot signal; detecting a reception quality signal indicating a
reception quality of the received OFDM signal based on an
equalized output; and controlling a position of the FFT window as the position
where the reception quality is the best condition, based on
the reception quality signal.
Claim 8
Dependent Claim
97 words
The method of claim 7, characterized by further
comprising detecting a difference of a part of the additive
information signals performed by the fast Fourier
transformation, and characterized in that : in the equalizing, at least one of the additive
information signals except the differential detection signal,
which is used for the differential detection, and the continual
pilot signal, are equalized as the reference of the
interpolated scattered pilot signal; and in the detection of the reception quality signal, the
reception quality signal is detected by using the equalized
output and an output of the differential detection.
Claim 9
Dependent Claim
53 words
The method of claim 7 or 8, characterized in that in the equalizing, at least one of the additive
information signals and the continual pilot signal performed
by the fast Fourier transformation, and the pilot signal
performed by the fast Fourier transformation are equalized
as the reference of the interpolated scattered pilot signal.
Claim 10
Dependent Claim
46 words
The method of claim 7, 8 or 9, characterized in that the detection of the reception quality signal includes: obtaining respective variance values from a
predetermined reference signal point for the respective
equalized output; and averaging the obtained variance values and detecting
the reception quality signal.
References Cited (Backward Citations)
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