Radio communication system, mobile terminal unit thereof, and azimuth determining method

A radio communication system comprising a transmitting station which transmits an azimuth designation signal having directivity toward a predetermined reference azimuth, and a plurality of transmitting/receiving stations which can receive said azimuth designation signal transmitted from said transmitting station,

• wherein a target transmitting/receiving station, included in said plurality of transmitting/receiving stations, comprises:
• a receiving section that receives said azimuth designation signal transmitted from said transmitting station;
• an arrival direction obtaining section that obtains an arrival direction of said azimuth designation signal received by said receiving section;
• an azimuth designation signal generating section that generates a new azimuth designation signal having directivity in a direction determined by said arrival direction of said azimuth designation signal obtained by said arrival direction obtaining section;
• and
• a transmitting section that transmits said new azimuth designation signal generated by said azimuth designation signal generating section, in such a manner that said new azimuth designation signal has a directivity in a direction designated by said new azimuth designation signal.

A radio communication system comprising:

• a plurality of transmitting stations and at least one transmitting/receiving station both arranged in a given area,
• wherein each of said plurality of transmitting stations comprises a transmitting section for transmitting an azimuth designation signal having directivity in a direction determined in accordance with a position within said area, and said transmitting/receiving station comprises a receiving section that receives said azimuth designation signal(s) when said azimuth designation signal(s) transmitted from one or more of said plurality of transmitting stations is/are receivable and/or when said azimuth designation signal(s) transmitted from said transmitting/receiving station(s) other than said transmitting/receiving station, in which said receiving section is included, is/are receivable;
• an arrival direction obtaining section that obtains an arrival direction of said azimuth designation signal(s) received by said receiving section;
• a received power measuring unit that respectively measures received power of said plurality of azimuth designation signals received;
• a vector generating section that generates a vector having magnitude of said received power and direction of said arrival direction on the basis of said received power and said arrival direction;
• a combined vector generating section that generates a combined vector by combining said vectors respectively generated for said received azimuth designation signals;
• an azimuth designation signal generating section that generates a new azimuth designation signal on the basis of the magnitude and the direction of said combined vector, by determining the direction of said combined vector as an arrival direction of an azimuth designation signal and by obtaining directional information on the basis of this arrival direction;
• and
• a transmitting section that transmits said new azimuth designation signal generated by said azimuth designation signal generating section with directivity in a direction of said combined vector or in a direction having a predetermined angle with said combined vector.

An azimuth determining method, using a plurality of transmitting/receiving stations arranged in a given area, for determining an azimuth in one or more of said transmitting/receiving stations, said method comprising:

• in a transmitting station, transmitting an azimuth designation signal so as to have directivity toward a predetermined reference azimuth;
• in said transmitting/receiving station, receiving said azimuth designation signal;
• obtaining an arrival direction of said azimuth designation signal;
• generating a new azimuth designation signal having directivity in a direction determined by said arrival direction;
• transmitting said new generated azimuth designation signal;
• and
• specifying said reference azimuth on the basis of said arrival directions of said azimuth designation signals transmitted from said transmitting station and said transmitting/receiving station(s), and determining an azimuth on the basis of said specified reference azimuth.

A transmitting/receiving station comprising:

• a receiving section that receives an azimuth designation signal, which is transmitted from a transmitting station so as to have directivity in a previously set reference azimuth;
• an arrival direction obtaining section that obtains an arrival direction of said azimuth designation signal received by said receiving section;
• an azimuth designation signal generating section that generates a new azimuth designation signal having directivity in a direction determined by said arrival direction of said azimuth designation signal;
• a reference azimuth specifying section that detects the direction of the directivity of said new azimuth designation signal generated by said azimuth designation signal generating section as a reference azimuth;
• and
• a transmitting section that transmits said new azimuth designation signal generated by said azimuth designation signal generating section so as to have directivity in a direction designated by said new azimuth designation signal.

A transmitting station for transmitting an azimuth designation signal having directivity toward a predetermined reference azimuth, said transmitting station comprising:

• an information holding section that holds data indicative of said reference azimuth;
• an azimuth designation signal generating section that generates an azimuth designation signal which designates said reference azimuth on the basis of said data indicative of said reference azimuth;
• and
• a transmitting section that transmits a signal having directivity in a direction designated by said azimuth designation signal generated by said azimuth designation signal generating section.