CDMA receiving apparatus, method, program and recording medium
First Claim
1. A CDMA receiving apparatus which receives radio-signal of CDMA scheme to perform a channel detection and channel demodulation operations, wherein said apparatus comprises a received signal wave-form buffer unit which digitalizes the amplitude of the wave-form of the signal which is received by a radio unit for recording the signal as data on the received signal wave-form;
- a delay profile generating unit for generating a delay profile which represent the distribution of the signal power value relative to the delay time on a path by calculating as a signal power value a sum of the correlation values which are obtained by multiplying said received signal wave-form data by a desired channel code over a time interval which is provided as a predetermined desired length of constraint if the time length of said received signal wave-form data recorded on said received signal wave-form buffer unit becomes a predetermined processing unit length;
a path search unit for obtaining the time of respective demodulation paths by detecting the time at which the signal power value of said delay profile peak to detect the path candidates used for demodulating said received signal and to select the demodulation paths which are to be applied for demodulation, having a number not more than predetermined maximum number of paths;
a channel estimating unit for demodulating the pilot symbols of respective demodulation paths by determining the correlation between said received signal wave-form data recorded on the received signal wave-form buffer unit and demodulation code assigned to said CDMA receiving apparatus on a symbol unit basis at said time of said respective demodulation paths which are selected by said path search unit and for estimating an adjustment angle for aligning phases of said respective demodulation paths from a result of demodulation of said pilot symbol;
a channel demodulating unit which determines correlations between said received signal wave-form data recorded on said receiving signal wave-form buffer unit and said demodulation code at said time of said respective selected demodulation paths, as demodulation symbols on a symbol unit basis and for adjusting the phases of the symbols which are determined for each demodulation path based upon said adjustment angle of said each demodulation path which is estimated by said channel estimating unit;
a RAKE unit which combines said demodulation symbols of said respective demodulation paths, the phases of which are aligned to obtain combined demodulation symbols for outputting them; and
a reception quality measuring unit for measuring the reception quality by comparing said combined demodulation symbol related with said pilot symbol of said combined demodulation symbols with a predetermined pilot pattern, and in that said demodulation paths which are selected in said path search unit are changed depending upon whether or not said reception quality measured by said reception quality measuring unit is lower than a predetermined preset reference value.
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Abstract
In a CDMA receiving apparatus, a delay profile using a desired constraint length is generated by a delay profile generating unit from received signal wave-form data recorded on a received signal wave-form buffer unit. Several demodulation paths are selected at peak position of the delay profile by the path search unit. Demodulation symbols which are generated from received signal wave-form data of each demodulation path by the channel demodulating unit are brought into in-phase by an adjustment angle which is obtained by the channel estimating unit. If the reception quality which is measured by the reception quality measuring unit is lower than a predetermined value for a combined demodulation symbol which is combined by a RAKE unit, the combination of said selected demodulation paths or the constraint length is changed to repeat the demodulation operation of the same received signal wave-form data.
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Citations
27 Claims
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1. A CDMA receiving apparatus which receives radio-signal of CDMA scheme to perform a channel detection and channel demodulation operations, wherein said apparatus comprises a received signal wave-form buffer unit which digitalizes the amplitude of the wave-form of the signal which is received by a radio unit for recording the signal as data on the received signal wave-form;
- a delay profile generating unit for generating a delay profile which represent the distribution of the signal power value relative to the delay time on a path by calculating as a signal power value a sum of the correlation values which are obtained by multiplying said received signal wave-form data by a desired channel code over a time interval which is provided as a predetermined desired length of constraint if the time length of said received signal wave-form data recorded on said received signal wave-form buffer unit becomes a predetermined processing unit length;
a path search unit for obtaining the time of respective demodulation paths by detecting the time at which the signal power value of said delay profile peak to detect the path candidates used for demodulating said received signal and to select the demodulation paths which are to be applied for demodulation, having a number not more than predetermined maximum number of paths;
a channel estimating unit for demodulating the pilot symbols of respective demodulation paths by determining the correlation between said received signal wave-form data recorded on the received signal wave-form buffer unit and demodulation code assigned to said CDMA receiving apparatus on a symbol unit basis at said time of said respective demodulation paths which are selected by said path search unit and for estimating an adjustment angle for aligning phases of said respective demodulation paths from a result of demodulation of said pilot symbol;
a channel demodulating unit which determines correlations between said received signal wave-form data recorded on said receiving signal wave-form buffer unit and said demodulation code at said time of said respective selected demodulation paths, as demodulation symbols on a symbol unit basis and for adjusting the phases of the symbols which are determined for each demodulation path based upon said adjustment angle of said each demodulation path which is estimated by said channel estimating unit;
a RAKE unit which combines said demodulation symbols of said respective demodulation paths, the phases of which are aligned to obtain combined demodulation symbols for outputting them; and
a reception quality measuring unit for measuring the reception quality by comparing said combined demodulation symbol related with said pilot symbol of said combined demodulation symbols with a predetermined pilot pattern, and in that said demodulation paths which are selected in said path search unit are changed depending upon whether or not said reception quality measured by said reception quality measuring unit is lower than a predetermined preset reference value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13)
- a delay profile generating unit for generating a delay profile which represent the distribution of the signal power value relative to the delay time on a path by calculating as a signal power value a sum of the correlation values which are obtained by multiplying said received signal wave-form data by a desired channel code over a time interval which is provided as a predetermined desired length of constraint if the time length of said received signal wave-form data recorded on said received signal wave-form buffer unit becomes a predetermined processing unit length;
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14. A CDMA receiving method which receives radio-signal of CDMA scheme to perform channel detection and channel demodulation operations, wherein there is provided a received signal wave-form buffer unit which digitalizes the amplitude of the wave-form of the signal which is received by a radio unit for recording the signal as data on the received signal wave-form, in that said method comprises a delay profile generating step for generating a delay profile which represent the distribution of the signal power value relative to the delay time on a path by calculating as a signal power value a sum of the correlation values which are obtained by multiplying said received signal wave-form data by a desired channel code over a time interval which is provided as a predetermined desired length of constraint if the time length of said received signal wave-form data recorded on said received signal wave-form buffer unit becomes a predetermined processing unit length;
- a path search step for obtaining the time of respective demodulation paths by detecting the time at which the signal power value of said delay profile peak to detect the path candidates used for demodulating said received signal and to select the demodulation paths which are to be applied for demodulation, having a number not more than predetermined maximum number of paths;
a channel estimating step for demodulating the pilot symbols of respective demodulation paths by determining the correlation between said received signal wave-form data recorded on the received signal wave-form buffer unit and demodulation code assigned to a CDMA receiving apparatus on a symbol unit basis at said time of said respective demodulation paths which are selected by said path search step and for estimating an adjustment angle for aligning phases of said respective demodulation paths from a result of demodulation of said pilot symbol;
a channel demodulating step which determines correlations between said received signal wave-form data recorded on said receiving signal wave-form buffer unit and said demodulation code at said time of said respective selected demodulation paths, as demodulation symbols on a symbol unit basis and for adjusting the phases of the symbols which are determined for each demodulation path based upon said adjustment angle of said each demodulation path which is estimated by said channel estimating step;
a RAKE step which combines said demodulation symbols of said respective demodulation paths, the phases of which are aligned to obtain combined demodulation symbols for outputting them; and
a reception quality measuring step for measuring the reception quality by comparing said combined demodulation symbol related with said pilot symbol of said combined demodulation symbols with a predetermined pilot pattern, and in that said demodulation paths which are selected in said path search step are changed depending upon whether or not said reception quality measured by said reception quality measuring step is lower than a predetermined preset reference value. - View Dependent Claims (15, 16, 17, 18, 19, 20, 21, 22, 23, 24, 25, 26, 27)
- a path search step for obtaining the time of respective demodulation paths by detecting the time at which the signal power value of said delay profile peak to detect the path candidates used for demodulating said received signal and to select the demodulation paths which are to be applied for demodulation, having a number not more than predetermined maximum number of paths;
Specification