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Claims  |
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What is claimed is:
1. A CDMA (Code Division Multiple Access) demodulator used in a CDMA
transmission which performs multiple access transmission by spreading a
signal, which includes a frame consisting of a pilot signal of a known
pattern and an information signal, into a wideband signal using a
spreading code faster than each information symbol in the information
signal, thereby generating a spread signal, said CDMA demodulator, which
demodulates the spread signal by using the spreading code, comprising:
an orthogonal filter including a plurality of delay elements, a plurality
of multipliers and an adder, said delay elements providing said spread
signal with successive delays each of an amount of 1/m of a chip interval
of said spreading code, where m is a positive integer, said multipliers
multiplying said spread signal and successively delayed spread signals by
tap coefficients obtained on the basis of said spreading code, and said
adder summing up outputs of said multipliers, said orthogonal filter
despreading said spread signal to generate a despread signal;
absolute phase estimating means for estimating received phases of a
received pilot signal by comparing said received pilot signal included in
said despread signal with said pilot signal of a known pattern, and for
estimating a received phase of each information symbol in said information
signal by interpolating said received phases of said received pilot
signal;
phase error compensation means for compensating received phase errors of
said received pilot signal on the basis of estimated received phases of
said received pilot signal, and for compensating a phase error of each
said information symbol on the basis of an estimated received phase of
said information symbol;
decision means for deciding said pilot signal whose phase has been
compensated, and for deciding said information symbol whose phase has been
compensated; and
tap coefficient control means for calculating said tap coefficients which
will minimize a mean square error of differences between an output of said
phase error compensation means and an output of said decision means, and
for feeding said tap coefficients to said orthogonal filter.
2. The CDMA demodulator as claimed in claim 1, wherein said tap coefficient
control means calculates said tap coefficients that will minimize said
mean square error for each symbol in said pilot signal, and calculates
said tap coefficients that will minimize said mean square error for each
symbol in said information signal.
3. The CDMA demodulator as claimed in claim 1, wherein said tap coefficient
control means calculates said tap coefficients that will minimize said
mean square error for each said pilot signal.
4. The CDMA demodulator as claimed in claim 1, wherein said tap coefficient
control means calculates said tap coefficients that will minimize said
mean square error for each said pilot signal, and calculates said tap
coefficients that will minimize said mean square error for each symbol in
said information signal.
5. A CDMA (Code Division Multiple Access) demodulator of a receiver of a
mobile station used in a CDMA transmission system whose forward link
channels from a base station to mobile stations include at least one pilot
channel and multiple traffic channels, said pilot channel transmitting
only a pilot signal of a known pattern, and said traffic channels
transmitting information signals, said CDMA transmission system spreading
said pilot signal and said information signals into wideband signals by
using spreading codes faster than a transmission rate of said pilot signal
and said information signals, thereby generating spread signals to perform
communications between said base station and said mobile stations in a
multiple access transmission, said CDMA demodulator comprising:
a pilot channel demodulating portion for demodulating said pilot channel;
and
a traffic channel demodulating portion provided for each said traffic
channel for demodulating said traffic channel,
wherein said pilot channel demodulating portion comprises:
a pilot channel orthogonal filter including a plurality of delay elements,
a plurality of multipliers and an adder, said delay elements providing
said spread signal of said pilot channel with successive delays each of an
amount of 1/m of a chip interval of said spreading codes, where m is a
positive integer, said multipliers multiplying said spread signal and
successively delayed spread signals of said pilot channel by tap
coefficients of said pilot channel obtained on the basis of said spreading
code of said pilot channel, and said adder summing up outputs of said
multipliers, said pilot channel orthogonal filter despreading said spread
signal of said pilot channel to generate a despread signal of said pilot
channel;
phase error estimating/averaging means for estimating received phases of
individual received pilot symbols of a received pilot signal included in
said despread signal of said pilot channel by comparing said received
pilot signal with said pilot signal of a known pattern of said pilot
channel, and for obtaining phase differences between said received pilot
symbols and an average signal obtained by averaging said received phases
of said received pilot symbols; and
pilot channel tap coefficient control means for calculating said tap
coefficients of said pilot channel, which will minimize a mean square
error of said phase differences between said received pilot symbols and
said average signal, and for feeding said tap coefficients to said pilot
channel orthogonal filter,
wherein said traffic channel demodulating portion comprises:
a traffic channel orthogonal filter including a plurality of delay
elements, a plurality of multipliers and an adder, said delay elements
providing said spread signal of said traffic channel with successive
delays each of an amount of 1/m of a chip interval of said spreading
codes, where m is a positive integer, said multipliers multiplying said
spread signal and successively delayed spread signals of said traffic
channel by tap coefficients of said traffic channel obtained on the basis
of said spreading code of said traffic channel, and said adder summing up
outputs of said multipliers, said traffic channel orthogonal filter
despreading said spread signal of said traffic channel to generate a
despread signal of said traffic channel;
traffic channel phase error compensation means for compensating a received
phase of each said information symbol in said information signal included
in said despread signal of said traffic channel on the basis of said
received phase of said pilot symbol corresponding said information symbol;
and
traffic channel tap coefficient control means for calculating tap
coefficients of said traffic channel, and for feeding said tap
coefficients to said traffic channel orthogonal filter,
and wherein
said demodulator further comprises decision means for deciding information
symbols whose phases have been compensated, and
said traffic channel tap coefficient control means calculates said tap
coefficients that will minimize a mean square error of differences between
said information symbols whose phases have been compensated and
information symbols outputted from said decision means.
6. A CDMA (Code Division Multiple Access) demodulator of a receiver of a
mobile station used in a CDMA transmission system whose forward link
channels from a base station to mobile stations include at least one pilot
channel and multiple traffic channels, said pilot channel transmitting
only a pilot signal of a known pattern, and said traffic channels
transmitting information signals, said CDMA transmission system spreading
said pilot signal and said information signals into wideband signals by
using spreading codes faster than a transmission rate of said pilot signal
and said information signals, thereby generating spread signals to perform
communications between said base station and said mobile stations in a
multiple access transmission, said CDMA demodulator comprising:
a pilot channel demodulating portion for demodulating said pilot channel;
and
a traffic channel demodulating portion provided for each said traffic
channel for demodulating said traffic channel,
wherein said pilot channel demodulating portion comprises:
a matched filter including a plurality of delay elements, a plurality of
multipliers and an adder, said delay elements providing said spread signal
of said pilot channel with successive delays each of an amount of 1/m of a
chip interval of said spreading codes, where m is a positive integer, said
multipliers multiplying said spread signal and successively delayed spread
signals of said pilot channel by tap coefficients of said pilot channel
obtained on the basis of said spreading code of said pilot channel, and
said adder summing up outputs of said multipliers, said pilot channel
orthogonal filter despreading said spread signal of said pilot channel to
generate a despread signal of said pilot channel; and
phase error estimating/averaging means for estimating received phases of
individual received pilot symbols of a received pilot signal included in
said despread signal of said pilot channel by comparing said received
pilot signal with said pilot signal of a known pattern of said pilot
channel, and for obtaining differences between said received pilot symbols
and an average signal obtained by averaging said received phases of said
received pilot symbols,
wherein said traffic channel demodulating portion comprises:
a traffic channel orthogonal filter including a plurality of delay
elements, a plurality of multipliers and an adder, said delay elements
providing said spread signal of said traffic channel with successive
delays each of an amount of 1/m of a chip interval of said spreading
codes, where m is a positive integer, said multipliers multiplying said
spread signal and successively delayed spread signals of said traffic
channel by tap coefficients of said traffic channel obtained on the basis
of said spreading code of said traffic channel, and said adder summing up
outputs of said multipliers, said traffic channel orthogonal filter
despreading said spread signal of said traffic channel to generate a
despread signal of said traffic channel;
traffic channel phase error compensation means for compensating a received
phase of each said information symbol in said information signal included
in said despread signal of said traffic channel on the basis of said
received phase of said pilot symbol corresponding said information symbol;
and
traffic channel tap coefficient control means for calculating tap
coefficients of said traffic channel, and for feeding said tap
coefficients to said traffic channel orthogonal filter,
and wherein
said demodulator further comprises decision means for deciding information
symbols whose phases have been compensated, and
said traffic channel tap coefficient control means calculates said tap
coefficients that will minimize a mean square error of differences between
said information symbols whose phases have been compensated and
information symbols outputted from said decision means.
7. A CDMA (Code Division Multiple Access) demodulator used in a CDMA
transmission which performs multiple access transmission by spreading a
signal, which includes a frame consisting of a pilot signal of a known
pattern and an information signal, into a wideband signal using a
spreading code faster than each information symbol in the information
signal, thereby generating a spread signal, said CDMA demodulator, which
demodulates the spread signals transmitted through multipaths by using the
spreading codes, comprising for each path:
an orthogonal filter including a plurality of delay elements, a plurality
of multipliers and an adder, said delay elements providing said spread
signal with successive delays each of an amount of 1/m of a chip interval
of said spreading code, where m is a positive integer, said multipliers
multiplying said spread signal and successively delayed spread signals by
tap coefficients obtained on the basis of said spreading code, and said
adder summing up outputs of said multipliers, said orthogonal filter
despreading said spread signal to generate a despread signal;
absolute phase estimating means for estimating received phases of a
received pilot signal by comparing said received pilot signal included in
said despread signal with said pilot signal of a known pattern, and for
estimating a received phase of each information symbol in said information
signal by interpolating said received phases of said received pilot
signal;
phase error compensation means for compensating received phase errors of
said received pilot signal on the basis of estimated received phases of
said received pilot signal, and for compensating a phase error of each
said information symbol on the basis of an estimated received phase of
said information symbol; and
tap coefficient control means for calculating said tap coefficients, and
for feeding them to said orthogonal filter,
wherein said demodulator further comprises:
a RAKE combiner for RAKE combining said pilot signals and said information
symbols whose phases have been compensated, by multiplying for each path
of said multipaths said pilot signal and said information symbols by
weighting factors; and
decision means for deciding a RAKE combined signal,
and wherein said tap coefficient control means of said each path calculates
said tap coefficients that will minimize mean square error of differences
between an output of said phase error compensation means of said each path
and signals obtained by sharing in terms of power an output of said
decision means in accordance with said weighting factors of said RAKE
combiner.
8. The CDMA demodulator as claimed in claim 7, wherein said tap coefficient
control means calculates said tap coefficients that will minimize said
mean square error for each symbol in said pilot signal, and calculates
said tap coefficients that will minimize said mean square error for each
symbol in said information signal.
9. The CDMA demodulator as claimed in claim 7, wherein said tap coefficient
control means calculates said tap coefficients that will minimize said
mean square error for each said pilot signal.
10. The CDMA demodulator as claimed in claim 7, wherein said tap
coefficient control means calculates said tap coefficients that will
minimize said mean square error for each said pilot signal, and calculates
said tap coefficients that will minimize said mean square error for each
symbol in said information signal.
11. The CDMA demodulator as claimed in claim 7, wherein said weighting
factors are received SIRs (Signal-to-Interference Ratios) of individual
paths of said multipaths.
12. A CDMA (Code Division Multiple Access) demodulator of a receiver of a
mobile station used in a CDMA transmission system whose forward link
channels from a base station to mobile stations include at least one pilot
channel and multiple traffic channels, said pilot channel transmitting
only a pilot signal of a known pattern, and said traffic channels
transmitting information signals, said CDMA transmission system spreading
said pilot signal and said information signals into wideband signals by
using spreading codes faster than a transmission rate of said pilot signal
and said information signals, thereby generating spread signals to perform
communications between said base station and said mobile stations in
multiple access transmission, said CDMA demodulator, which demodulates the
spread signals transmitted through multipaths by using the spreading
codes, comprising for each path of said multipaths:
a pilot channel demodulating portion for demodulating said pilot channel;
and
a traffic channel demodulating portion provided for each said traffic
channel for demodulating said traffic channel,
wherein said pilot channel demodulating portion comprises:
a pilot channel orthogonal filter including a plurality of delay elements,
a plurality of multipliers and an adder, said delay elements providing
said spread signal of said pilot channel with successive delays each of an
amount of 1/m of a chip interval of said spreading codes, where m is a
positive integer, said multipliers multiplying said spread signal and
successively delayed spread signals of said pilot channel by tap
coefficients of said pilot channel obtained on the basis of said spreading
code of said pilot channel, and said adder summing up outputs of said
multipliers, said pilot channel orthogonal filter despreading said spread
signal of said pilot channel to generate a despread signal of said pilot
channel;
phase error estimating/averaging means for estimating received phases of
individual received pilot symbols of a received pilot signal included in
said despread signal of said pilot channel by comparing said received
pilot signal with said pilot signal of a known pattern of said pilot
channel, and for obtaining phase differences between said received pilot
symbols and an average signal obtained by averaging said received phases
of said received pilot symbols; and
pilot channel tap coefficient control means for calculating said tap
coefficients of said pilot channel, which will minimize a mean square
error of said phase differences between said received pilot symbols and
said average signal, and for feeding said tap coefficients to said pilot
channel orthogonal filter,
wherein said traffic channel demodulating portion comprises:
a traffic channel orthogonal filter including a plurality of delay
elements, a plurality of multipliers and an adder, said delay elements
providing said spread signal of said traffic channel with successive
delays each of an amount of 1/m of a chip interval of said spreading
codes, where m is a positive integer, said multipliers multiplying said
spread signal and successively delayed spread signals of said traffic
channel by tap coefficients of said traffic channel obtained on the basis
of said spreading code of said traffic channel, and said adder summing up
outputs of said multipliers, said traffic channel orthogonal filter
despreading said spread signal of said traffic channel to generate a
despread signal of said traffic channel;
traffic channel phase error compensation means for compensating a received
phase of each said information symbol in said information signal included
in said despread signal of said traffic channel on the basis of said
received phase of said pilot symbol corresponding said information symbol;
and
traffic channel tap coefficient control means for calculating tap
coefficients of said traffic channel, and for feeding said tap
coefficients to said traffic channel orthogonal filter,
and wherein said demodulator further comprises:
a RAKE combiner for RAKE combining said information symbols whose phases
have been compensated, by multiplying for each path of said multipaths
said information symbols by weighting factors; and
decision means for deciding a RAKE combined signal,
and wherein said traffic channel tap coefficient control means of said each
path calculates said tap coefficients that will minimize mean square error
of differences between an output of said traffic channel phase error
compensation means of said each path and one of signals obtained by
sharing in terms of power an output of said decision means in accordance
with said weighting factors of said RAKE combiner.
13. The CDMA demodulator as claimed in claim 12, wherein said weighting
factors are received SIRs (Signal-to-Interference Ratios) of individual
paths of said multipaths.
14. A CDMA (Code Division Multiple Access) demodulator of a receiver of a
mobile station used in a CDMA transmission system whose forward link
channels from a base station to mobile stations include at least one pilot
channel and multiple traffic channels, said pilot channel transmitting
only a pilot signal of a known pattern, and said traffic channels
transmitting information signals, said CDMA transmission system spreading
said pilot signal and said information signals into wideband signals by
using spreading codes faster than a transmission rate of said pilot signal
and said information signals, thereby generating spread signals to perform
communications between said base station and said mobile stations in
multiple access transmission, said CDMA demodulator, which demodulates the
spread signals transmitted through multipaths by using the spreading
codes, comprising for each path of said multipaths:
a pilot channel demodulating portion for demodulating said pilot channel;
and
a traffic channel demodulating portion provided for each said traffic
channel for demodulating said traffic channel,
wherein said pilot channel demodulating portion comprises:
a pilot channel matched filter including a plurality of delay elements, a
plurality of multipliers and an adder, said delay elements providing said
spread signal of said pilot channel with successive delays each of an
amount of 1/m of a chip interval of said spreading codes, where m is a
positive integer, said multipliers multiplying said spread signal and
successively delayed spread signals of said pilot channel by tap
coefficients of said pilot channel obtained on the basis of said spreading
code of said pilot channel, and said adder summing up outputs of said
multipliers, said pilot channel matched filter despreading said spread
signal of said pilot channel to generate a despread signal of said pilot
channel; and
phase error estimating/averaging means for estimating received phases of
individual received pilot symbols of a received pilot signal included in
said despread signal of said pilot channel by comparing said received
pilot signal with said pilot signal of a known pattern of said pilot
channel, and for obtaining differences between said received pilot symbols
and an average signal obtained by averaging said received phases of said
received pilot symbols,
wherein said traffic channel demodulating portion comprises:
a traffic channel orthogonal filter including a plurality of delay
elements, a plurality of multipliers and an adder, said delay elements
providing said spread signal of said traffic channel with successive
delays each of an amount of 1/m of a chip interval of said spreading
codes, where m is a positive integer, said multipliers multiplying said
spread signal and successively delayed spread signals of said traffic
channel by tap coefficients of said traffic channel obtained on the basis
of said spreading code of said traffic channel, and said adder summing up
outputs of said multipliers, said traffic channel orthogonal filter
despreading said spread signal of said traffic channel to generate a
despread signal of said traffic channel;
traffic channel phase error compensation means for compensating a received
phase of each said information symbol in said information signal included
in said despread signal of said traffic channel on the basis of said
received phase of said pilot symbol corresponding said information symbol;
and
traffic channel tap coefficient control means for calculating tap
coefficients of said traffic channel, and for feeding said tap
coefficients to said traffic channel orthogonal filter,
and wherein said demodulator further comprises:
a RAKE combiner for RAKE combining said information symbols whose phases
have been compensated, by multiplying for each path of said multipaths
said information symbols by weighting factors; and
decision means for deciding a RAKE combined signal,
and wherein said traffic channel tap coefficient control means of said each
path calculates said tap coefficients that will minimize mean square error
of differences between an output of said traffic channel phase error
compensation means of said each path and one of signals obtained by
sharing in terms of power an output of said decision means in accordance
with said weighting factors of said RAKE combiner.
15. The CDMA demodulator as claimed in claim 14, wherein said weighting
factors are received SIRs (Signal-to-Interference Ratios) of individual
paths of said multipaths.
16. A CDMA (Code Division Multiple Access) transmission system carrying out
communications between a base station and mobile stations in multiple
access transmission by using spread signals generated by spreading
information signals into wideband signals using spreading codes whose rate
is higher than a transmission rate of said information signals, said CDMA
transmission system including forward link channels from the base station
to the mobile stations, each of said forward link channels comprising:
at least one pilot channel for transmitting only a pilot signal of a known
pattern; and
a plurality of traffic channels for transmitting said information signals,
wherein a demodulator of a receiver of said mobile stations comprises:
a pilot channel demodulating portion for demodulating said pilot channel;
and
a traffic channel demodulating portion provided for each said traffic
channel for demodulating said traffic channel,
wherein said pilot channel demodulating portion comprises:
a pilot channel filter including a plurality of delay elements, a plurality
of multipliers and an adder, said delay elements providing said spread
signal of said pilot channel with successive delays each of an amount of
1/m of a chip interval of said spreading codes, where m is a positive
integer, said multipliers multiplying said spread signal and successively
delayed spread signals of said pilot channel by tap coefficients of said
pilot channel obtained on the basis of said spreading code of said pilot
channel, and said adder summing up outputs of said multipliers, said pilot
channel orthogonal filter despreading said spread signal of said pilot
channel to generate a despread signal of said pilot channel;
phase error estimating/averaging means for estimating received phases of
individual received pilot symbols of a received pilot signal included in
said despread signal of said pilot channel by comparing said received
pilot signal with said pilot signal of a known pattern of said pilot
channel, and for obtaining phase differences between said received pilot
symbols and an average signal obtained by averaging said received phases
of said received pilot symbols; and
pilot channel tap coefficient control means for calculating said tap
coefficients of said pilot channel, which will minimize a mean square
error of said phase differences between said received pilot symbols and
said average signal, and for feeding said tap coefficients to said pilot
channel orthogonal filter,
wherein said traffic channel demodulating portion comprises:
a traffic channel orthogonal filter including plurality of delay elements,
a plurality of multipliers and an adder, said delay elements providing
said spread signal of said traffic channel with successive delays each of
an amount of 1/m of a chip interval of said spreading codes, where m is a
positive integer, said multipliers multiplying said spread signal and
successively delayed spread signals of said traffic channel by tap
coefficients of said traffic channel obtained on the basis of said
spreading code of said traffic channel, and said adder summing up outputs
of said multipliers, said traffic channel orthogonal filter despreading
said spread signal of said traffic channel to generate a despread signal
of said traffic channel;
traffic channel phase error compensation means for compensating a received
phase of each said information symbol in said information signal included
in said despread signal of said traffic channel on the basis of said
received phase of said pilot symbol corresponding to said information
symbol; and
traffic channel tap coefficient control means for calculating tap
coefficients of said traffic channel, and for feeding said tap
coefficients to said traffic channel orthogonal filter,
and wherein
said demodulator further comprises decision means for deciding information
symbols whose phases have been compensated, and
said traffic channel tap coefficient control means calculates said tap
coefficients that will minimize a mean square error of differences between
said information symbols whose phases have been compensated and
information symbols outputted from said decision means.
17. A CDMA (Code Division Multiple Access) transmission system carrying out
communications between a base station and mobile stations in multiple
access transmission by using spread signals generated by spreading
information signals into wideband signals using spreading codes whose rate
is higher than a transmission rate of said information signals, said CDMA
transmission system including forward link channels from the base station
to the mobile stations, each of said forward link channels comprising:
at least one pilot channel for transmitting only a pilot signal of a known
pattern; and
a plurality of traffic channels for transmitting said information signals,
wherein a demodulator of a receiver of said mobile stations comprises:
a pilot channel demodulating portion for demodulating said pilot channel;
and
a traffic channel demodulating portion provided for each said traffic
channel for demodulating said traffic channel,
wherein said pilot channel demodulating portion comprises:
a matched filter including a plurality of delay elements, a plurality of
multipliers and an adder, said delay elements providing said spread signal
of said pilot channel with successive delays each of an amount of 1/m of a
chip interval of said spreading codes, where m is a positive integer, said
multipliers multiplying said spread signal and successively delayed spread
signals of said pilot channel by tap coefficients of said pilot channel
obtained on the basis of said spreading code of said pilot channel, and
said adder summing up outputs of said multipliers, said pilot channel
orthogonal filter despreading said spread signal of said pilot channel to
generate a despread signal of said pilot channel; and
phase error estimating/averaging means for estimating received phases of
individual received pilot symbols of a received pilot signal included in
said despread signal of said pilot channel by comparing said received
pilot signal with said pilot signal of a known pattern of said pilot
channel, and for obtaining differences between said received pilot symbols
and an average signal obtained by averaging said received phases of said
received pilot symbols,
wherein said traffic channel demodulating portion comprises:
a traffic channel orthogonal filter including a plurality of delay
elements, a plurality of multipliers and an adder, said delay elements
providing said spread signal of said traffic channel with successive
delays each of an amount of 1/m of a chip interval of said spreading
codes, where m is a positive integer, said multipliers multiplying said
spread signal and successively delayed spread signals of said traffic
channel by tap coefficients of said traffic channel obtained on the basis
of said spreading code of said traffic channel, and said adder summing up
outputs of said multipliers, said traffic channel orthogonal filter
despreading said spread signal of said traffic channel to generate a
despread signal of said traffic channel;
traffic channel phase error compensation means for compensating a received
phase of each said information symbol in said information signal included
in said despread signal of said traffic channel on the basis of said
received phase of said pilot symbol corresponding to said information
symbol; and
traffic channel tap coefficient control means for calculating tap
coefficients of said traffic channel, and for feeding said tap
coefficients to said traffic channel orthogonal filter,
and wherein
said demodulator further comprises decision means for deciding information
symbols whose phases have been compensated, and
said traffic channel tap coefficient control means calculates said tap
coefficients that will minimize a mean square error of differences between
said information symbols whose phases have been compensated and
information symbols outputted from said decision means.
18. A CDMA (Code Division Multiple Access) transmission system carrying out
communications between a base station and mobile stations in multiple
access transmission by using spread signals generated by spreading
information signals into wideband signals using spreading codes whose rate
is higher than a transmission rate of said information signals, said CDMA
transmission system including forward link channels from the base station
to the mobile stations, each of said forward link channels comprising:
at least one pilot channel for transmitting only a pilot signal of a known
pattern; and
a plurality of traffic channels for transmitting said information signals,
wherein a demodulator of a receiver of said mobile stations comprises for
each path of said multipaths:
a pilot channel demodulating portion for demodulating said pilot channel;
and
a traffic channel demodulating portion provided for each said traffic
channel for demodulating said traffic channel,
wherein said pilot channel demodulating portion comprises:
a pilot channel orthogonal filter including a plurality of delay elements,
a plurality of multipliers and an adder, said delay elements providing
said spread signal of said pilot channel with successive delays each of an
amount of 1/m of a chip interval of said spreading codes, where m is a
positive integer, said multipliers multiplying said spread signal and
successively delayed spread signals of said pilot channel by tap
coefficients of said pilot channel obtained on the basis of said spreading
code of said pilot channel, and said adder summing up outputs of said
multipliers, said pilot channel orthogonal filter despreading said spread
signal of said pilot channel to generate a despread signal of said pilot
channel;
phase error estimating/averaging means for estimating received phases of
individual received pilot symbols of a received pilot signal included in
said despread signal of said pilot channel by comparing said received
pilot signal with said pilot signal of a known pattern of said pilot
channel, and for obtaining phase differences between said received pilot
symbols and an average signal obtained by averaging said received phases
of said received pilot symbols; and
pilot channel tap coefficient control means for calculating said tap
coefficients of said pilot channel, which will minimize a mean square
error of said phase differences between said received pilot symbols and
said average signal, and for feeding said tap coefficients to said pilot
channel orthogonal filter,
wherein said traffic channel demodulating portion comprises:
a traffic channel orthogonal filter including plurality of delay elements,
a plurality of multipliers and an adder, said delay elements providing
said spread signal of said traffic channel with successive delays each of
an amount of 1/m of a chip interval of said spreading codes, where m is a
positive integer, said multipliers multiplying said spread signal and
successively delayed spread signals of said traffic channel by tap
coefficients of said traffic channel obtained on the basis of said
spreading code of said traffic channel, and said adder summing up outputs
of said multipliers, said traffic channel orthogonal filter despreading
said spread signal of said traffic channel to generate a despread signal
of said traffic channel;
traffic channel phase error compensation means for compensating a received
phase of each said information symbol in said information signal included
in said despread signal of said traffic channel on the basis of said
received phase of said pilot symbol corresponding to said information
symbol; and
traffic channel tap coefficient control means for calculating tap
coefficients of said traffic channel, and for feeding said tap
coefficients to said traffic channel orthogonal filter,
and wherein said demodulator further comprises:
a RAKE combiner for RAKE combining said pilot signal and said information
symbols whose phases have been compensated, by multiplying for each path
of said multipaths said pilot signal and said information symbols by
weighing factors; and
decision means for deciding a RAKE combined signal,
and wherein said traffic channel tap coefficient control means of said each
path calculates said tap coefficients that will minimize mean square error
of differences between an output of said traffic channel phase error
compensation means of said each path and one of signals obtained by
sharing in terms of power an output of said decision means in accordance
with said weighing factors of said RAKE combiner.
19. A CDMA (Code Division Multiple Access) transmission system carrying out
communications between a base station and mobile stations in multiple
access transmission by using spread signals generated by spreading
information signals into wideband signals using spreading codes whose rate
is higher than a transmission rate of said information signals, said CDMA
transmission system including forward link channels from the base station
to the mobile stations, each of said forward link channels comprising:
at least one pilot channel for transmitting only a pilot signal of a known
pattern; and
a plurality of traffic channels for transmitting said information signals,
wherein a demodulator of a receiver of said mobile stations comprises for
each path of said multipaths:
a pilot channel demodulating portion for demodulating said pilot channel;
and
a traffic channel demodulating portion provided for each said traffic
channel for demodulating said traffic channel,
wherein said pilot channel demodulating portion comprises:
a pilot channel matched filter including a plurality of delay elements, a
plurality of multipliers and an adder, said delay elements providing said
spread signal of said pilot channel with successive delays each of an
amount of 1/m of a chip interval of said spreading codes, where m is a
positive integer, said multipliers multiplying said spread signal and
successively delayed spread signals of said pilot channel by tap
coefficients of said pilot channel obtained on the basis of said spreading
code of said pilot channel, and said adder summing up outputs of said
multipliers, said pilot channel orthogonal filter despreading said spread
signal of said pilot channel to generate a despread signal of said pilot
channel; and
phase error estimating/averaging means for estimating received phases of
individual received pilot symbols of a received pilot signal included in
said despread signal of said pilot channel by comparing said received
pilot signal with said pilot signal of a known pattern of said pilot
channel, and for obtaining phase differences between said received pilot
symbols and an average signal obtained by averaging said received phases
of said received pilot symbols,
wherein said traffic channel demodulating portion comprises:
a traffic channel orthogonal filter including a plurality of delay
elements, a plurality of multipliers and an adder, said delay elements
providing said spread signal of said traffic channel with successive
delays each of an amount of 1/m of a chip interval of said spreading
codes, where m is a positive integer, said multipliers multiplying said
spread signal and successively delayed spread signals of said traffic
channel by tap coefficients of said traffic channel obtained on the basis
of said spreading code of said traffic channel, and said adder summing up
outputs of said multipliers, said traffic channel orthogonal filter
despreading said spread signal of said traffic channel to generate a
despread signal of said traffic channel;
traffic channel phase error compensation means for compensating a received
phase of each said information symbol in said information signal included
in said despread signal of said traffic channel on the basis of said
received phase of said pilot symbol corresponding to said information
symbol; and
traffic channel tap coefficient control means for calculating tap
coefficients of said traffic channel, and for feeding said tap
coefficients to said traffic channel orthogonal filter,
and wherein said demodulator further comprises:
a RAKE combiner for RAKE combining said pilot signal and said information
symbols whose phases have been compensated, by multiplying for each path
of said multipaths said pilot signal and said information symbols by
weighing factors; and
decision means for deciding a RAKE combined signal,
and wherein said traffic channel tap coefficient control | | |
