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Claims  |
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Having thus described our invention, we claim:
1. A receiver comprising:
desired signal estimation means for converting a desired signal sequence
candidate into an estimated received desired signal in accordance with a
channel parameter and outputting said estimated received desired signal;
interference signal estimation means for converting an interference signal
sequence candidate into an estimated received interference signal in
accordance with a channel parameter and outputting said estimated received
interference signal;
error estimation means connected to the outputs of said desired signal
estimation means and said interference signal estimation means, for
generating an estimation error signal by subtracting, from a received
signal, said estimated received desired signal from said desired signal
estimation means and said estimated received interference signal from said
interference signal estimation means;
state estimation means connected to the output of said error estimation
means and to inputs of said desired signal estimation means and said
interference signal estimation means for producing a plurality of desired
signal sequence candidates and a plurality of interference signal sequence
candidates respectively corresponding to a predetermined plurality of
sequences of states of signal transition and for providing said plurality
of desired signal sequence candidates and said plurality of interference
signal sequence candidates to said desired signal estimation means and
said interference signal estimation means, respectively, said state
estimation means being operative to output, as the result of a sequence
decision, that one of said desired signal sequence candidates that is
estimated to be a desired signal sequence contained in said received
signal on the basis of said estimation error signal generated by said
error estimation means; and
control means connected to the output of said state estimation means and to
inputs of said desired signal estimation means and said interference
signal estimation means, for controlling said channel parameters of said
desired signal estimation means and said interference signal estimation
means by an adaptation algorithm on the basis of said desired signal
sequence, said interference signal sequence and said estimation error
signal;
said desired signal estimation means and said interference signal
estimation means being formed by first and second transversal filters with
predetermined numbers of taps, respectively, and said control means
generating, as said channel parameters, first and second tap coefficient
vectors representing channel impulse responses and providing said first
and second tap coefficient vectors to said first and second transversal
filters.
2. A receiver comprising:
desired signal estimation means for converting a desired signal sequence
candidate into an estimated received desired signal in accordance with a
channel parameter and outputting said estimated received desired signal;
interference signal estimation means for converting an interference signal
sequence candidate into an estimated received interference signal in
accordance with a channel parameter and outputting said estimated received
interference signal;
error estimation means connected to the outputs of said desired signal
estimation means and said interference signal estimation means, for
generating an estimation error signal by subtracting, from a received
signal, said estimated received desired signal from said desired signal
estimation means and said estimated received interference signal from said
interference signal estimation means;
state estimation means connected to the output of said error estimation
means and to inputs of said desired signal estimation means and said
interference signal estimation means for producing a plurality of desired
signal sequence candidates and a plurality of interference signal sequence
candidates respectively corresponding to a predetermined plurality of
sequences of states of signal transition and for providing said plurality
of desired signal sequence candidates and said plurality of interference
signal sequence candidates to said desired signal estimation means and
said interference signal estimation means, respectively, said state
estimation means being operative to output, as the result of a sequence
decision, that one of said desired signal sequence candidates that is
estimated to be a desired signal sequence contained in said received
signal on the basis of said estimation error signal generated by said
error estimation means; and
control means connected to the output of said state estimation means and to
inputs of said desired signal estimation means and said interference
signal estimation means, for controlling said channel parameters of said
desired signal estimation means and said interference signal estimation
means by an adaptation algorithm on the basis of said desired signal
sequence, said interference signal sequence and said estimation error
signal;
said desired signal estimation means, said interference signal estimation
means, said error estimation means and said control means constituting a
first diversity branch, said receiver including a second diversity branch
of the same construction as said first diversity branch, said error
estimation means of said first and second diversity branches being
supplied with quasi-coherently detected signal sample values obtained from
received signals at different positions, respectively, and said state
estimation means comprising first and second square means for calculating
the squares of estimation errors from said error estimation means of said
first and second diversity branches and adder means which adds the outputs
from said first and second square means and outputs the added result as a
likelihood signal corresponding to its likelihood, said state estimation
means generating a set of a desired signal symbol sequence candidate and
an interference signal symbol sequence candidate and providing said set to
said desired signal estimation means, said interference signal estimation
means and said control means of said first and second diversity branches.
3. A receiver comprising:
desired signal estimation means for converting a desired signal sequence
candidate into an estimated received desired signal in accordance with a
channel parameter and outputting said estimated received desired signal;
interference signal estimation means for converting an interference signal
sequence candidate into an estimated received interference signal in
accordance with a channel parameter and outputting said estimated received
interference signal;
error estimation means connected to the outputs of said desired signal
estimation means and said interference signal estimation means, for
generating an estimation error signal by subtracting, from a received
signal, said estimated received desired signal from said desired signal
estimation means and said estimated received interference signal from said
interference signal estimation means;
state estimation means connected to the output of said error estimation
means and to inputs of said desired signal estimation means and said
interference signal estimation means for producing a plurality of desired
signal sequence candidates and a plurality of interference signal sequence
candidates respectively corresponding to a predetermined plurality of
sequences of states of signal transition and for providing said plurality
of desired signal sequence candidates and said plurality of interference
signal sequence candidates to said desired signal estimation means and
said interference signal estimation means, respectively, said state
estimation means being operative to output, as the result of a sequence
decision, that one of said desired signal sequence candidates that is
estimated to be a desired signal sequence contained in said received
signal on the basis of said estimation error signal generated by said
error estimation means; and
control means connected to the output of said state estimation means and to
inputs of said desired signal estimation means and said interference
signal estimation means, for controlling said channel parameters of said
desired signal estimation means and said interference signal estimation
means by an adaptation algorithm on the basis of said desired signal
sequence, said interference signal sequence and said estimation error
signal;
said state estimation means comprising: state sequence candidate generating
means which generates a first transition state sequence candidate
corresponding to said desired signal symbol sequence candidate and a
second transition state sequence candidate corresponding to said
interference signal symbol sequence candidate; and first and second
modulated signal generating means which generate, as said desired signal
sequence candidate and said interference signal sequence candidate, first
and second symbol sequence candidates sequentially modulated in accordance
with said first and second transition state sequence candidates,
respectively.
4. A method for cancelling an interference signal from a received signal in
a receiver which comprises error estimation means, state estimation means,
desired signal estimation means, interference signal estimation means and
channel estimation means, said method comprising:
A. a step wherein upon each input of a quasi-coherently detected signal
sample value into said error estimation means, said state estimation means
sequentially generates a plurality of first symbol sequence candidates and
a plurality of second symbol sequence candidates corresponding to a
plurality of transition state sequence candidates for received signals of
desired and interference waves;
B. a step wherein said desired signal estimation means and said
interference signal estimation means respectively perform convolutional
operations of said first and second symbol sequence candidates and channel
impulse response estimated values for said desired and interference waves
from said channel estimation means to generate an estimated received
interference signal;
C. a step wherein said error estimation means subtracts said estimated
received desired signal and said estimated received interference signal
from said sample value to generate an estimation error signal; and
D. a step wherein said state estimation means calculates the likelihood
corresponding to said estimation error signal for said set of first and
second symbol sequence candidates to decide a desired signal sequence
candidate of the maximum likelihood and outputs the result of said
decision;
said method including an interference wave training signal period during
which a symbol sequence corresponding to an interference wave training
signal is provided, as a substitute for said second symbol sequence
candidate, to said interference signal estimation means and said channel
estimation means, and said channel estimation means outputs said channel
impulse response estimated value corresponding to said symbol sequence
candidate of said desired signal which provides the maximum likelihood.
5. A method for cancelling an interference signal from a received signal in
a receiver which comprises error estimation means, state estimation means,
desired signal estimation means, interference signal estimation means and
channel estimation means, said method comprising:
A. a step wherein upon each input of a quasi-coherently detected signal
sample value into said error estimation means, said state estimation means
sequentially generates a plurality of first symbol sequence candidates and
a plurality of second symbol sequence candidates corresponding to a
plurality of transition state sequence candidates for received signals of
desired and interference waves;
B. a step wherein said desired signal estimation means and said
interference signal estimation means respectively perform convolutional
operations of said first and second symbol sequence candidates and channel
impulse response estimated values for said desired and interference waves
from said channel estimation means to generate an estimated received
interference signal;
C. a step wherein said error estimation means subtracts said estimated
received desired signal and said estimated received interference signal
from said sample value to generate an estimation error signal; and
D. a step wherein said state estimation means calculates the likelihood
corresponding to said estimation error signal for said set of first and
second symbol sequence candidates to decide a desired signal sequence
candidate of the maximum likelihood and outputs the result of said
decision;
said step A being a step wherein, in a predetermined period of a received
signal, said channel estimation means sets the number of states to a value
larger than the numbers of possible transition states for desired and
interference waves and increases the numbers of said first and second
symbol sequence candidates accordingly and said channel estimation means
outputs said channel impulse response estimated values corresponding to
said first and second symbol sequence candidates of said desired and
interference waves which provide the maximum likelihood in said
predetermined period.
6. A method for cancelling an interference signal from a received signal in
a receiver which comprises error estimation means, state estimation means,
desired signal estimation means, interference signal estimation means and
channel estimation means, said method comprising:
A. a step wherein upon each input of a quasi-coherently detected signal
sample value into said error estimation means, said state estimation means
sequentially generates a plurality of first symbol sequence candidates and
a plurality of second symbol sequence candidates corresponding to a
plurality of transition state sequence candidates for received signals of
desired and interference waves;
B. a step wherein said desired signal estimation means and said
interference signal estimation means respectively perform convolutional
operations of said first and second symbol sequence candidates and channel
impulse response estimated values for said desired and interference waves
from said channel estimation means to generate an estimated received
interference signal;
C. a step wherein said error estimation means subtracts said estimated
received desired signal and said estimated received interference signal
from said sample value to generate an estimation error signal;
D. a step wherein said state estimation means calculates the likelihood
corresponding to said estimation error signal for said set of first and
second symbol sequence candidates to decide a desired signal sequence
candidate of the maximum likelihood and outputs the result of said
decision; and
E. a step wherein in desired and interference wave training signal periods,
training signal symbol sequences respectively corresponding to desired and
interference wave training signals are provided to said desired signal
estimation means and said interference signal estimation means, as
substitutes for said first and second symbol sequence candidates, said
training symbol sequences being provided to said channel estimation means
as well, and said channel impulse response estimated values to be provided
to said desired signal estimation means and said interference signal
estimation means are determined so that said estimation error signal of
said error estimation means is minimized in said training signal periods.
7. A method for cancelling an interference signal from a received signal in
a receiver which comprises error estimation means, state estimation means,
desired signal estimation means, interference signal estimation means and
channel estimation means, said method comprising:
A. a step wherein upon each input of a quasi-coherently detected signal
sample value into said error estimation means, said state estimation means
sequentially generates a plurality of first symbol sequence candidates and
a plurality of second symbol sequence candidates corresponding to a
plurality of transition state sequence candidates for received signals of
desired and interference waves;
B. a step wherein said desired signal estimation means and said
interference signal estimation means respectively perform convolutional
operations of said first and second symbol sequence candidates and channel
impulse response estimated values for said desired and interference waves
from said channel estimation means to generate an estimated received
interference signal;
C. a step wherein said error estimation means subtracts said estimated
received desired signal and said estimated received interference signal
from said sample value to generate an estimation error signal;
D. a step wherein said state estimation means calculates the likelihood
corresponding to said estimation error signal for said set of first and
second symbol sequence candidates to decide a desired signal sequence
candidate of the maximum likelihood and outputs the result of said
decision; and
E. a step of selecting a path which provides the maximum state transition
path metric, by use of the Viterbi algorithm, for each of all
predetermined possible transition states of a combination of said desired
and interference signals and, upon each selection of said path for each
state at each point in time, updating channel parameters for said desired
and interference signals on the basis of said first and second symbol
sequence candidates corresponding to said selected path.
8. A method for cancelling an interference signal from a received signal in
a receiver which comprises error estimation means, state estimation means,
desired signal estimation means, interference signal estimation means and
channel estimation means, said method comprising:
A. a step wherein upon each input of a quasi-coherently detected signal
sample value into said error estimation means, said state estimation means
sequentially generates a plurality of first symbol sequence candidates and
a plurality of second symbol sequence candidates corresponding to a
plurality of transition state sequence candidates for received signals of
desired and interference waves;
B. a step wherein said desired signal estimation means and said
interference signal estimation means respectively perform convolutional
operations of said first and second symbol sequence candidates and channel
impulse response estimated values for said desired and interference waves
from said channel estimation means to generate an estimated received
interference signal;
C. a step wherein said error estimation means subtracts said estimated
received desired signal and said estimated received interference signal
from said sample value to generate an estimation error signal;
D. a step wherein said state estimation means calculates the likelihood
corresponding to said estimation error signal for said set of first and
second symbol sequence candidates to decide a desired signal sequence
candidate of the maximum likelihood and outputs the result of said
decision; and
E. a step wherein states groups composed of combinations of possible
transition states of said desired signal and possible transition states of
said interference signal are defined; the state transition between
adjacent points in time is limited to one path which provides the maximum
path metric between respective state groups; and upon each selection of
one path on the basis of said path metric, channel impulse responses for
said desired and interference signals are updated in accordance with said
first and second symbol sequence candidates of said desired and
interference signals corresponding to the selected state transition.
9. A communication system which uses a receiver to receive a desired signal
in signals transmitted from a plurality of transmitting stations, said
plurality of transmitting stations each including random generating means
for generating a pseudo-random number and phase shift means for shifting
the phase of the signal to be transmitted, by an amount corresponding to
said pseudo-random number; said receiver comprising:
desired signal estimation means for converting a desired signal sequence
candidate into an estimated received desired signal in accordance with a
channel parameter and outputting said estimated received desired signal;
interference signal estimation means for converting an interference signal
sequence candidate into an estimated received interference signal in
accordance with a channel parameter and outputting said estimated received
interference signal;
error estimation means connected to the outputs of said desired signal
estimation means and said interference signal estimation means, for
generating an estimation error signal by subtracting, from a received
signal, said estimated received desired signal from said desired signal
estimation means and said estimated received interference signal from said
interference signal estimation means;
state estimation means connected to the output of said error estimation
means and to inputs of said desired signal estimation means and said
interference signal estimation means for producing a plurality of desired
signal sequence candidates and a plurality of interference signal sequence
candidates respectively corresponding to a predetermined plurality of
sequences of states of signal transition and for providing said plurality
of desired signal sequence candidates and said plurality of interference
signal sequence candidates to said desired signal estimation means and
said interference signal estimation means, respectively, said state
estimation means being operative to output, as the result of a sequence
decision, that one of said desired signal sequence candidates that is
estimated to be a desired signal sequence contained in said received
signal on the basis of said estimation error signal generated by said
error estimation means; and
control means connected to the output of said state estimation means and to
inputs of said desired signal estimation means and said interference
signal estimation means, for controlling said channel parameters of said
desired signal estimation means and said interference signal estimation
means by an adaptation algorithm on the basis of said desired signal
sequence, said interference signal sequence and said estimation error
signal.
10. A communication system which uses receiver to receive a desired signal
in signals transmitted from a plurality of transmitting stations, each
transmitting station including random generating means for generating a
pseudo-random number and power control means for changing the amplitude of
the signal to be transmitted in accordance with said pseudeo-random
number; said receiver comprising:
desired signal estimation means for converting a desired signal sequence
candidate into an estimated received desired signal in accordance with a
channel parameter and outputting said estimated received desired signal;
interference signal estimation means for converting an interference signal
sequence candidate into an estimated received interference signal in
accordance with a channel parameter and outputting said estimated received
interference signal;
error estimation mean connected to the outputs of said desired signal
estimation means and said interference signal estimation means, for
generating an estimation error signal by subtracting, from a received
signal, said estimated received desired signal from said desired signal
estimation means and said estimated received interference signal from said
interference signal estimation means;
state estimation means connected to the output of said error estimation
means and to inputs of said desired signal estimation means and said
interference signal estimation means for producing a plurality of desired
signal sequence candidates and a plurality of interference signal sequence
candidates respectively corresponding to predetermined plurality of
sequence of states of signal transition and for providing said plurality
of desired signal sequence candidates and said plurality of interference
signal sequence candidates to said desired signal estimation means and
said interference signal estimation means, respectively, said state
estimation means being operative to output, as the result of a sequence
decision, that one of said desired signal sequence candidates that is
estimated to be a desired signal sequence contained in said received
signal on the basis of said estimation error signal generated by said
error estimation means, and
control mean connected to the output of said state estimation means and to
inputs of said desired signal estimation means and said interference
signal estimation means, for controlling said channel parameters of said
parameters of said desired signal estimation means and said interference
signal estimation means by an adaptation algorithm on the basis of said
desired signal sequence, said interference signal sequence and said
estimation error signal.
11. A method for cancelling an interference signal from a received signal
in a receiver which comprises error estimation means, state estimation
means, desired signal estimation means, interference signal estimation
means and channel estimation means, said method comprising:
A. a step wherein upon each input of a quasi-coherently detected signal
sample value into said error estimation means, said state estimation means
sequentially generates a plurality of first symbol sequence candidates and
a plurality of second symbol sequence candidates corresponding to a
plurality of transition state sequence candidates for received signals of
desired and interference waves;
B. a step wherein said desired signal estimation means and said
interference signal estimation means respectively perform convolutional
operations of said first and second symbol sequence candidates and channel
impulse response estimated values for said desired and interference waves
from said channel estimation means to generate an estimated received
desired signal and an estimated received interference signal;
C. a step wherein said error estimation means subtracts said estimated
received desired signal and said estimated received interference signal
from said sample value to generate an estimation error signal; and
D. a step wherein said state estimation means calculates the likelihood
corresponding to said estimation error signal for said set of first and
second symbol sequence candidates to decide a desired signal sequence
candidate of the maximum likelihood and outputs the result of said
decision;
said method including a desired wave training signal period during which a
symbol sequence corresponding to a desired wave training signal is
provided, as a substitute for said first symbol sequence candidate, to
said desired signal estimation means and said channel estimation means,
and said channel estimation means outputs said channel impulse response
estimated value corresponding to said symbol sequence candidate of said
interference wave which provides the maximum likelihood.
12. The receiver of claim 1, wherein said state estimation means comprises:
first maximum likelihood sequence estimation means which generates a
desired signal symbol sequence candidate for the transition state of said
desired signal and makes a maximum likelihood sequence estimation for said
desired signal symbol candidate on the basis of said estimation error
signal from said error estimation means; desired signal modulated signal
generating means which modulates said desired signal symbol sequence
candidate from said first maximum likelihood sequence estimation means and
outputs said desired signal sequence candidate to said desired signal
estimation means; second maximum likelihood sequence estimation means
which generates an interference signal symbol sequence candidate for the
transition state of said interference signal and makes a maximum
likelihood sequence estimation for said interference signal symbol
sequence candidate on the basis of said estimation error signal from said
error estimation means; and interference signal modulated signal
generating means which modulates said interference signal symbol sequence
candidate from said second maximum likelihood sequence estimation means
and outputs said interference signal sequence candidate to said
interference signal estimation means.
13. The receiver of claim 1, wherein said state estimation means comprises:
maximum likelihood sequence estimation means which generates a plurality
of sets of desired and interference signal symbol sequence candidates for
respective state sequences each formed by a combination of the transition
state for said desired signal and the transition state for said
interference signal and makes a maximum likelihood estimation for each of
said sets of desired and interference signal symbol sequence candidates on
the basis of the corresponding estimation error signal from said error
estimation means; and desired signal modulated signal generating means and
interference signal modulated signal generating means which respectively
modulate said desired signal sequence candidate and said interference
signal sequence candidate obtainable from said sets of candidates
outputted from said maximum likelihood sequence estimation means and
output said desired signal sequence candidate and said interference signal
sequence candidate to said desired signal estimation means and said
interference signal estimation means, respectively.
14. The receiver of claim 1, wherein said state estimation means comprises:
maximum likelihood sequence estimation means which generates a plurality
of desired signal symbol sequence candidates for each state sequence of
said desired signal and makes a maximum likelihood sequence estimation for
each of said desired signal symbol sequence candidates on the basis of the
corresponding estimation error signal from said error estimation means;
desired signal modulated signal generating means which modulates each of
said desired signal symbol sequence candidates from said maximum
likelihood sequence estimation means and outputs said desired signal
sequence candidate to said desired signal estimation means; maximum
likelihood decision means which generates a plurality of interference
signal symbol sequence candidates for each state sequence of said
interference signal and makes a maximum likelihood decision for each to
said interference signal symbol sequence candidates on the basis of the
corresponding estimation error signal from said error estimation means;
and interference signal modulated signal generating means which modulates
each of said interference signal symbol sequence candidates from said
maximum likelihood decision means and outputs said interference signal
sequence candidate to said interference signal estimation means.
15. The receiver of claim 1, wherein said state estimation means comprises:
maximum likelihood decision means which generates a plurality of desired
signal symbol sequence candidates for each state sequence of said desired
signal and makes a maximum likelihood decision for each of said desired
signal symbol sequence candidates on the basis of the corresponding
estimation error signal from said error estimation means; desired signal
modulated signal generating means which modulates each of said desired
signal symbol sequence candidates from said maximum likelihood decision
means and outputs said desired signal sequence candidate to said desired
signal estimation means; maximum likelihood sequence estimation means
which generates a plurality of interference signal symbol sequence
candidates for each state sequence of said interference signal and makes a
maximum likelihood sequence estimation for each of said interference
signal symbol sequences on the basis of the corresponding estimation error
signal from said error estimation means; and interference signal modulated
signal generating means which modulates each of said interference signal
symbol sequence candidates from said maximum likelihood sequence
estimation means and outputs said interference signal sequence candidate
to said interference signal estimation means.
16. The receiver of claim 1, wherein said state estimation means comprises:
maximum likelihood decision means which generates a plurality of desired
signal symbol sequence candidates for each state sequence of said desired
signal and make a maximum likelihood decision for each of said desired
signal symbol sequence candidates on the basis of the corresponding
estimation error signal from said error estimation means; desired signal
modulated signal generating means which modulates each of said desired
signal symbol sequence candidates from said maximum likelihood decision
means and outputs said desired signal sequence candidate to said desired
signal estimation means; maximum likelihood decision means which generates
a plurality of interference signal symbol sequence candidates for each
state sequence of the state sequence of said interference signal and makes
a maximum likelihood decision for each of said interference signal symbol
sequences on the basis of the corresponding to estimation error signal
from said error estimation means; and interference signal modulated signal
generating means which modulates each of said interference signal symbol
sequence candidates from said maximum likelihood decision means and output
said interference signal sequence candidate to said interference signal
estimation means.
17. The receiver of claim 1, wherein said state estimation means comprises:
maximum likelihood sequence estimation means which generates a plurality
of desired signal symbol sequence candidates for each state sequence of
said desired signal and makes a maximum likelihood sequence estimation for
each of said desired signal symbol sequence candidates on the basis of the
corresponding estimation error signal from said error estimation means;
desired signal modulated signal generating means which modulates each of
said desired signal symbol sequence candidates from said maximum
likelihood sequence estimation means and outputs said desired signal
sequence candidate to said desired signal estimation means; inverse filter
means which is controlled by the inverse of said second tap coefficient
vector and generates an interference signal sequence estimated from said
estimation error signal; and symbol decision means which makes a
symbol-by-symbol decision for said estimated interference signal sequence
and outputs it as said interference signal sequence candidate.
18. The receiver of any one of claims 1 through 12, wherein said control
means comprises: tap coefficient update means which is supplied with said
desired signal symbol sequence candidate and said interference signal
symbol sequence candidate from said state estimation means and said
estimation error signal from said error estimation means and whereby said
first and second tap coefficient vectors stored for each transition state
are updated for each possible transition state of said desired signal and
said interference signal through said adaptation algorithm; tap
coefficient holding means which holds said updated first and second tap
coefficient vectors for each transition state; and tap coefficient
switching means which selects, for each transition state, the
corresponding first and second tap coefficient vectors from said tap
coefficient holding means and sets them in said first and second
transversal filters.
19. The receiver of any one of claims 12 through 15, wherein said maximum
likelihood sequence estimation means is means which makes said estimation
following a Viterbi algorithm.
20. The receiver of claim 1, which further comprises: training signal
storage means having stored therein training signals of a plurality of
base stations; and first switching means whereby, in a training signal
period of a received signal of a desired wave, said desired signal symbol
sequence candidate from said state estimation means is switched to a
desired wave training signal symbol sequence for supply to said first
transversal filter and said control means from said training signal
storage means; and wherein said control means adaptively updates, on the
basis of said estimation error signal, said first tap coefficient vector
for each transition state of said desired wave training signal symbol
sequence in said training signal period.
21. The receiver of claim 20, which further comprises second switching
means whereby, in said training signal period, said interference signal
sequence candidate from said state estimation means is switched to an
interference wave training signal for supply to said second transversal
filter and said control means from said training signal storage means, and
wherein said control means adaptively updates, on the basis of said
estimation error signal, said second tap coefficient vector for each
transition state of said interference wave training signal in said
training signal period.
22. The receiver of claim 20 or 21, wherein said switching means is
provided at the input side of said modulated signal generating means.
23. The receiver of claim 1, wherein at least one of said desired signal
estimation means and said interference signal estimation means includes
complex multiplier means which rotates the phase of a complex signal
output of said transversal filter in accordance with a carrier center
frequency difference between desired and interference waves.
24. The receiver of claim 8, wherein said first and second modulated signal
generating means respectively comprise: first and second mapping logic
circuit means which convert said transition state sequences provided
thereto into first and second modulated symbol sequences of desired
modulated forms; and first and second converting means which convert said
first and second modulated symbol sequences from said first and second
mapping logic circuit means into said desired signal symbol sequence
candidate and said interference signal symbol sequence candidate,
respectively.
25. The method of claim 6, wherein said receiver has prestored in memory
means a plurality of preknown training patterns corresponding to different
receivable training signals, said method selecting that one of said
training patterns which provides a training signal symbol sequence which
has the highest correlation to a received signal and using a symbol
sequence corresponding to said selecting training pattern as said training
symbol sequence.
26. The method of claim 6 or 25, wherein training patterns for said desired
and interference waves are those which are high in the auto-correlation of
their symbol sequences but low in the correlation between said symbol
sequences.
27. The method of claim 26, wherein said training patterns are determined
so that their symbol sequences are orthogonal to each other.
28. The communication system of claim 9, which includes timing generating
means for applying a common timing signal to at least two of said
transmitting stations, said transmitting stations including transmitting
power control means for controlling the amplitudes of said signals to be
transmitted on the basis of said timing signal so that said signals have
different amplitudes.
29. The communication system of claim 10, wherein said each transmitting
station includes second random generating means for generating a second
pseudorandom number and phase shift means for changing the phase of said
signal to be transmitted by an amount corresponding to said second
pseudo-random number.
30. The communication system of claim 19, 28, or 29, wherein said each
transmitting station transmits the signal with a burst and said phase
shift means changes the phase of said signal to be transmitted on the
basis of said random number for each burst. |
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