EP0975101A2
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Diversity receiver
Assignee: NEC Corp
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Filing: 1999-07-20
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Granted: —
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Expires: 2019-07-20
Abstract
Abstract A diversity receiver (2) is disclosed with an object to improve deteriorated transmission due to fading even when frequency selective fading resulting from multipaths occurs in a propagation path. The diversity receiver (2) is provided with two lines, each line comprising an antenna (10a, b), an orthogonal detector (20a, b), first sampling and quantizing means (31a, b), second sampling and quantizing means (32a, b), a serial-parallel conversion circuit (40a, b), and a Fourier transform circuit (50a, b). In each of the lines, a modulated signal transmitted from a transmitter (1) is received and processed. In a diversity processing unit (60), optimal diversity processing for each subcarrier is performed using the received and processed signals in respective lines. In this manner, an improvement is made in deteriorated transmission quality due to multipath fading between the receiver (2) and the transmitter (1) for transmitting OFM modulated signals.
Inventors
- 👤 Takeshi Yamamoto
Bibliographic Details
Application Number
—
Jurisdiction
EP
Data Source
google_patents
Last Synchronized
2026-10-26 04:39
CPC Classifications
H; H04; H04B; H04B7/00; H04B7/02; H04B7/04; H04B7/08; H04B7/0837; H04B7/0842; H04B7/0845; H04B7/0848; H04B7/0857
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
260 words
A diversity receiver (2) comprising: two antennas (10a, b) for receiving a modulated signal
transmitted from a transmitter (1); two orthogonal detectors (20a, b), each of said orthogonal
detectors (20a, b) for converting the modulated signal received
through one of said two antennas (10a, b) into a complex analogue
baseband signal and outputting the converted signal; two sets of sampling and quantizing means (31a, b; 32a,
b), each set of said sampling and quantizing means (31a, b;
32a, b) for sampling and quantizing the complex analogue base-band
signal provided from one of said two orthogonal detectors
(20a, b); two serial-parallel conversion circuits (40a, b), each of
said serial-parallel conversion circuits (40a, b) for serial-parallel
converting the baseband signal sampled and quantized
at one of said two sets of sampling and quantizing means (31a,
b; 32a, b); two Fourier transform circuits (50a, b) each of said
Fourier transform circuits (50a, b) for Fourier transforming
the baseband signal serial-parallel converted at one of said
two serial-parallel conversion circuits (40a, b) to separate
the modulated signal transmitted from the transmitter (1) into
signals for each subcarrier; a diversity processing unit (60) for performing optimal
diversity processing for each subcarrier using two signals provided
from said two Fourier transform circuits (50a, b); a parallel-serial conversion circuit (70) for parallel-serial
converting the signal diversity processed at said diversity
processing unit (60) to generate I, Q signals in time series;
and a demodulator (90) for demodulating the I, Q signals generated
at said parallel-serial conversion circuit (40a, b) and
outputting the demodulated signal as demodulated data.
Claim 2
Dependent Claim
131 words
The diversity receiver according to claim 1, wherein
each of said two orthogonal detectors (20a, b) converts the
modulated signal received through said antennas (10a, b) into
two complex analogue baseband signals which are orthogonal to
each other and outputting the converted signals, each of said two sets of sampling and quantizing means
(31a, b; 32a, b) comprising first sampling and quantizing means
(31a, b) for sampling and quantizing one of the analogue complex
baseband signals provided from one of said orthogonal detectors
(20a, b) to generate a sampled and quantized I signal
and second sampling and quantizing means (32a, b) for sampling
and quantizing the other of the analogue complex baseband signals
provided from the one of said orthogonal detectors (20a,
b) to generate a sampled and quantized Q signal.
Claim 3
Dependent Claim
221 words
The diversity receiver according to claim 1 or 2,
wherein said diversity processing unit (60) comprises: two propagation path characteristic estimating sections
(61a, b), each of said propagation path characteristic estimating
sections (61a, b) for estimating a propagation path characteristic
of a propagation path to the transmitter based on the
signals which have been Fourier transformed at one of said two
Fourier transform circuits (50a, b) to be separated for each
subcarrier and a known reference signal for estimating a propagation
path characteristic which is periodically inserted into
a signal transmitted from the transmitter (1); two complex conjugate sections (62a, b), each of said complex
conjugate sections (62a, b) for generating a complex conjugate
of the propagation path characteristic estimated at one
of said two propagation path characteristic estimating sections
(61a, b); two complex multipliers (63a, b), each of said complex
multipliers (63a, b) for complex multiplying the signals which
have been Fourier transformed at one of said two Fourier transform
circuits (50a, b) to be separated for each subcarrier by
the complex conjugate generated at one of said two complex conjugate
sections (62a, b); and a wave combiner (64) for combining the multiplication
results at said two complex multipliers (63a, b) for each subcarrier
and providing the combined result to said parallel-serial
conversion circuit (70) as a diversity processed signal.
Claim 4
Dependent Claim
197 words
The diversity receiver according to claim 1 or 2,
wherein said diversity processing unit (60) comprises: two propagation path characteristic estimating sections
(61a, b), each of said propagation path characteristic estimating
sections (61a, b) for estimating a propagation path characteristic
of a propagation path to the transmitter based on the
signals which have been Fourier transformed at one of said two
Fourier transform circuits (50a, b) to be separated for each
subcarrier and a known reference signal for estimating a propagation
path characteristic which is periodically inserted into
a signal transmitted from the transmitter (1); a wave amplitude characteristic comparator (65) for providing
a selection signal for selecting a signal received
through a propagation path exhibiting a high amplitude for each
subcarrier based on the propagation path characteristics estimated
at said two propagation path characteristic estimating
sections (61a, b); and selecting means (66) for receiving the signals provided
from said two Fourier transform circuits (50a, b) and selecting
the signal received through the propagation path exhibiting a
high amplitude from the signals provided from said two Fourier
transform circuits (50a, b) for each subcarrier based on the
selection signal provided from said wave amplitude characteristic
comparator (65).
Claim 5
Dependent Claim
31 words
The diversity receiver according to anyone of the
claims 1 to 4, wherein each of the first and second sampling
and quantizing means (31a, b; 32a, b) comprises an A/D converter.
References Cited (Backward Citations)
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