US 5,694,388 A · CDMA demodulator and demodulation method

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.

3 more elements

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.

13 more elements

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.

12 more elements

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.

7 more elements

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.

15 more elements

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.

14 more elements

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 more elements

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.

16 more elements

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 more elements

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 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.

18 more elements

A CDMA (Code Division Multiple Access) demodulation method 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 demodulation method, which demodulates the spread signal by using the spreading code, comprising:

a step of outputting a despread signal by 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, by multiplying said spread signal and successively delayed spread signals by tap coefficients obtained on the basis of said spreading code, and by summing up results of multiplications to despread said spread signal;
an absolute phase estimating step of 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 of estimating a received phase of each information symbol in said information signal by interpolating said received phases of said received pilot signal;
a phase error compensation step of compensating received phase errors of said received pilot signal on the basis of estimated received phases of said received pilot signal, and of compensating a phase error of each said information symbol on the basis of an estimated received phase of said information symbol;
a decision step of deciding said pilot signal whose phase has been compensated, and of deciding said information symbol whose phase has been compensated;
and
a tap coefficient calculation step of calculating said tap coefficients which will minimize a mean square error of differences between an output of said phase error compensation step and an output of said decision step.

3 more elements

A CDMA (Code Division Multiple Access) demodulation method 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 demodulation method comprising:

a step of outputting a despread signal of said pilot signal by 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, by 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 by summing up results of multiplications to despread said spread signal of said pilot channel;
a phase error estimating/averaging step of 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 of obtaining phase differences between said received pilot symbols and an average signal obtained by averaging said received phases of said received pilot symbols;
a step of 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;
a step of outputting a despread signal of said traffic channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said traffic channel;
a traffic channel phase error compensation step of 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;
a decision step of deciding information symbols whose phases have been compensated;
and
a step of calculating said tap coefficients that will minimize a mean square error of differences between said information symbols whose phases have been compensated and information symbols which have been decided.

5 more elements

A CDMA (Code Division Multiple Access) demodulation method 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 demodulation method comprising:

a step of outputting a despread signal of said pilot signal by 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, by 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 by summing up results of multiplications to despread said spread signal of said pilot channel;
a phase error estimating/averaging step of 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 of obtaining differences between said received pilot symbols and an average signal obtained by averaging said received phases of said received pilot symbols;
a step of outputting a despread signal of said traffic channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said traffic channel;
a traffic channel phase error compensation step of 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;
a step of deciding information symbols whose phases have been compensated;
and
a step of calculating said tap coefficients that will minimize a mean square error of differences between said information symbols whose phases have been compensated and information symbols which have been decided.

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A CDMA (Code Division Multiple Access) demodulation method 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 demodulation method, which demodulates the spread signals transmitted through multipaths by using the spreading codes, comprising for each path:

a step of outputting a despread signal by 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, by multiplying said spread signal and successively delayed spread signals by tap coefficients obtained on the basis of said spreading code, and by summing up results of multiplications to despread said spread signal;
an absolute phase estimating step of 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 of estimating a received phase of each information symbol in said information signal by interpolating said received phases of said received pilot signal;
a phase error compensation step of compensating received phase errors of said received pilot signal on the basis of estimated received phases of said received pilot signal, and of compensating a phase error of each said information symbol on the basis of an estimated received phase of said information symbol;
a RAKE combining step of 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;
a decision step of deciding a RAKE combined signal;
and
a step of calculating said tap coefficients that will minimize mean square error of differences between an output of said phase error compensation step of said each path and signals obtained by sharing in terms of power an output of said decision step in accordance with said weighting factors of said RAKE combining.

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A CDMA (Code Division Multiple Access) demodulation method 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 demodulation method, which demodulates the spread signals transmitted through multipaths by using the spreading codes, comprising for each path of said multipaths:

a step of outputting a despread signal of said pilot channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said pilot channel;
a phase error estimating/averaging step of 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 of obtaining phase differences between said received pilot symbols and an average signal obtained by averaging said received phases of said received pilot symbols;
a step of 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;
a step of outputting a despread signal of said traffic channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said traffic channel;
a traffic channel phase error compensation step of 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;
a RAKE combining step of RAKE combining said information symbols whose phases have been compensated, by multiplying for each path of said multipaths said information symbols by weighting factors;
a decision step of deciding a RAKE combined signal;
and
a step of calculating said tap coefficients that will minimize mean square error of differences between an output of said traffic channel phase error compensation step of said each path and one of signals obtained by sharing in terms of power an output of said decision step in accordance with said weighting factors of said RAKE combining.

6 more elements

A CDMA (Code Division Multiple Access) demodulation method 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 demodulation method, which demodulates the spread signals transmitted through multipaths by using the spreading codes, comprising for each path of said multipaths:

a step of outputting a despread signal of said pilot channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said pilot channel;
a phase error estimating/averaging step of 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 of obtaining differences between said received pilot symbols and an average signal obtained by averaging said received phases of said received pilot symbols;
a step of outputting a despread signal of said traffic channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said traffic channel;
a traffic channel phase error compensation step of 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;
a RAKE combining step of RAKE combining said information symbols whose phases have been compensated, by multiplying for each path of said multipaths said information symbols by weighting factors;
a decision step of deciding a RAKE combined signal;
and
a step of calculating said tap coefficients that will minimize mean square error of differences between an output of said traffic channel phase error compensation step of said each path and one of signals obtained by sharing in terms of power an output of said decision step in accordance with said weighting factors of said RAKE combining.

5 more elements

A CDMA (Code Division Multiple Access) transmission method 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 method comprising:

a step of transmitting from said base station to said mobile stations only a pilot signal of a known pattern through at least one pilot channel;
and
a step of transmitting said information signals through a plurality of traffic channels,
wherein a demodulation method of a receiver of said mobile stations comprises:
a step of outputting a despread signal of said pilot channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said pilot channel;
a phase error estimating/averaging step of 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 of obtaining phase differences between said received pilot symbols and an average signal obtained by averaging said received phases of said received pilot symbols;
a pilot channel tap coefficient calculation step of 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;
a step of outputting a despread signal of said traffic channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said traffic channel;
a traffic channel phase error compensation step of 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;
a decision step of deciding information symbols whose phases have been compensated;
and
a step of calculating said tap coefficients that will minimize a mean square error of differences between said information symbols whose phases have been compensated and information symbols which have been decided.

9 more elements

A CDMA (Code Division Multiple Access) transmission method 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 method comprising:

a step of transmitting from said base station to said mobile stations only a pilot signal of a known pattern through at least one pilot channel;
and
a step of transmitting said information signals through a plurality of traffic channels,
wherein a demodulation method of a receiver of said mobile stations comprises:
a step of outputting a despread signal of said pilot channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said pilot channel;
a phase error estimating/averaging step of 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 of obtaining phase differences between said received pilot symbols and an average signal obtained by averaging said received phases of said received pilot symbols;
a step of outputting a despread signal of said traffic channel by 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, by 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 by summing up results of multiplication to despread said spread signal of said traffic channel;
a traffic channel phase error compensation step of 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;
a decision step of deciding information symbols whose phases have been compensated;
and
a step of calculating said tap coefficients that will minimize a mean square error of differences between said information symbols whose phases have been compensated and information symbols which have been decided.

8 more elements

A CDMA (Code Division Multiple Access) transmission method 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 method comprising:

a step of transmitting from said base station to said mobile stations only a pilot signal of a known pattern through at least one pilot channel;
and
a step of transmitting said information signals through a plurality of traffic channels,
wherein a demodulation method of a receiver of said mobile stations comprises for each path of said multipaths:
a step of outputting a despread signal of said pilot channel by 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, by 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 by summing up results of multiplications to despread said spread signal of said pilot channel;
a phase error estimating/averaging step of 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 of obtaining phase differences between said received pilot symbols and an average signal obtained by averaging said received phases of said received pilot symbols;
a step of 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;
a step of outputting a despread signal of said traffic channel by 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, by 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 by summing up results of multiplication to despread said spread signal of said traffic channel;
a traffic channel phase error compensation step of 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;
a RAKE combining step of 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;
a decision step of deciding a RAKE combined signal;
and
a step of calculating said tap coefficients that will minimize mean square error of differences between an output of said traffic channel phase error compensation step of said each path and one of signals obtained by sharing in terms of power an output of said decision step in accordance with said weighing factors of said RAKE combining.

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CDMA demodulator and demodulation method

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CDMA demodulator and demodulation method

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Abstract

Claims38