Mobile communication apparatus with distance measuring unit

A radio communication system comprising:

• a base station and a mobile station which can communicate with each other by radio;
• first means provided in the mobile station for transmitting a first radio-frequency signal containing a predetermined pseudo-noise code signal toward the base station;
• second means provided in the mobile station for detecting a first timing at which the first means transmits the first radio-frequency signal;
• third means provided in the base station for receiving the first radio-frequency signal transmitted from the first means in the mobile station, and for repeating the first radio-frequency signal and transmitting the first radio-frequency signal as a second radio-frequency signal toward the mobile station;
• fourth means provided in the mobile station for receiving the second radio-frequency signal transmitted from the third means in the base station after the first means in the mobile station transmits the first radio-frequency signal;
• fifth means provided in the mobile station for converting the second radio-frequency signal received by the fourth means into a baseband signal;
• a memory provided in the mobile station and storing the predetermined pseudo-noise code signal;
• sixth means provided in the mobile station for calculating a correlation between the baseband signal generated by the fifth means and the predetermined pseudo-noise code signal stored in the memory;
• seventh means provided in the mobile station for detecting a second timing at which the correlation calculated by the sixth means peaks substantially;
• said seventh means comprising:
• first sub-means for differentiating the calculated correlation into a differentiation result;
• second sub-means for deciding whether or not the differentiation result generated by the first sub-means becomes smaller than a predetermined reference value;
• and
• third sub-means for using a timing at which the second sub-means decides that the differentiation result becomes smaller than the predetermined reference value as the second timing at which the calculated correlation peaks substantially;
• eighth means provided in the mobile station for calculating a time interval between the first timing detected by the second means and the second timing detected by the seventh means;
• and
• ninth means provided in the mobile station for calculating a distance between the mobile station and the base station on the basis of the time interval calculated by the eighth means.

A radio communication apparatus in a mobile station which can communicate with a base station radio, the base station having a function of repeating a received radio signal, the apparatus comprising:

• first means for transmitting a first radio-frequency signal containing a predetermined pseudo-noise code signal toward the base station;
• second means for detecting a first timing at which the first means transmits the first radio-frequency signal;
• third means for receiving a second radio-frequency signal after the first means transmits the first radio-frequency signal;
• fourth means for converting the second radio-frequency signal received by the third means into a baseband signal;
• a memory storing the predetermined pseudo-noise code signal;
• fifth means for calculating a correlation between the baseband signal generated by the fourth means and the predetermined pseudo-noise code signal stored in the memory;
• a differentiator for differentiating the correlation calculated by the fifth means;
• sixth means for deciding whether or not a value represented by an output signal of the differentiator becomes smaller than a predetermined reference value;
• seventh means for detecting a second timing at which the sixth means decides that the value represented by the output signal of the differentiator becomes smaller than the predetermined reference value, the second timing being indicative of a timing at which the calculated correlation peaks substantially;
• eighth means for calculating a time interval between the first timing detected by the second means and the second timing detected by the seventh means;
• and
• ninth means for calculating a distance between the mobile station and the base station on the basis of the time interval calculated by the eighth means.

A radio communication system comprising:

• a base station and a mobile station which can communicate with each other by radio;
• first means provided in the mobile station for transmitting a first radio-frequency signal containing a predetermined pseudo-noise code signal toward the base station;
• second means provided in the mobile station for detecting a first timing at which the first means transmits the first radio-frequency signal;
• third means provided in the base station for receiving the first radio-frequency signal transmitted from the first means in the mobile station, and for repeating the first radio-frequency signal and transmitting the first radio-frequency signal as a second radio-frequency signal toward the mobile station;
• fourth means provided in the mobile station for receiving the second radio-frequency signal transmitted from the third means in the base station after the first means in the mobile station transmits the first radio-frequency signal;
• fifth means provided in the mobile station for converting the second radio-frequency signal received by the fourth means into a baseband signal;
• a memory provide in the mobile station and storing the predetermined pseudo-noise code signal;
• sixth means provide in the mobile station for calculating a correlation between the baseband signal generated by the fifth means and the predetermined pseudo-noise code signal stored in the memory;
• a differentiator provided in the mobile station for differentiating the correlation calculated by the sixth means;
• seventh means provided in the mobile station for deciding whether or not a value represented by an output signal of the differentiator becomes smaller than a predetermined reference value;
• eighth means for detecting a second timing at which the seventh means decides that the value represented by the output signal of the differentiator becomes smaller than the predetermined reference value, the timing being indicative of a timing at which the calculated correlation peaks substantially;
• ninth means provided in the mobile station for calculating a time interval between the first timing detected by the second means and the second timing detected by the eighth means;
• and
• tenth means provided in the mobile station for calculating a distance between the mobile station and the base station on the basis of the time interval calculated by the ninth means.

A mobile communicating apparatus having a function of measuring a distance, comprising;

• a radio portion for processing a radio frequency signal;
• a first low pass filter for limiting a band to a baseband;
• a distance measurement data store portion for storing distance measurement data of a pseudo noise code mainly used in a spread spectrum system;
• a multiplier for multiplying an output signal of the first low pass filter and the distance measurement data;
• an integrator for integrating an output signal of the multiplier;
• a threshold value detector for monitoring an integration value of the integrator, and outputting a threshold value detection signal when detecting the integration value which is equal to or greater than a threshold value;
• a differentiator for sampling an output signal of the integrator in response to a high rate clock signal equal to “n” times a distance measurement data clock signal, comparing the threshold value and the output signal of the integrator between clock pulses thereof, and outputting an arrival detection signal for the distance measurement data when it become sequel to or smaller than the threshold value;
• a received data reproducing portion for reproducing received data from a received signal;
• a memory for storing at least processing delay times caused in the radio portion, the first low pass filter, and a second low pass filter indicated later;
• a data transmission portion for transmitting at least the distance measurement data and processing delay time data of the radio portion, the first low pass filter, and the second low pass filter indicated later;
• and
• the second low pass filter for limiting a band of a transmission signal.