Base station, mobile station, communication system, transmission control method, and mobile station control program

A communication system comprising a base station configured to transmit a pilot signal at a predetermined transmission power, and a mobile station configured to transmit a preamble to the base station prior to a start of transmission/reception of data, the communication system being configured to implement radio communication based on code division multiplexing between the base station and the mobile station,

• wherein the mobile station comprises:
• spreading means for spreading the preamble with a spreading code corresponding to any one of the reception power or the signal interference ratio about the pilot signal at the mobile station, the preamble transmission power of the mobile station, and the combination of the reception power or the signal interference ratio of the pilot signal at the mobile station with the preamble transmission power of the mobile station, based on any one of correspondence information between the spreading code used for the preamble and, the reception power or the signal interference ratio of the pilot signal at the mobile station, correspondence information between the spreading code and the preamble transmission power of the mobile station, and correspondence information between the spreading code and the combination of the reception power or the signal interference ratio of the pilot signal at the mobile station with the preamble transmission power of the mobile station;
• and
• preamble transmitting means for transmitting the preamble after the spreading process to the base station;
• and
• wherein the base station comprises:
• determining means for determining at least one, of a transmission power and a downlink transmission rate for a signal directed to the mobile station, and an uplink transmission rate for transmission of information from the mobile station, corresponding to at least the spreading code, based on any one of correspondence information between the spreading code used for the preamble and, the reception power or the signal interference ratio of the pilot signal at the mobile station, correspondence information between the spreading code and the preamble transmission power of the mobile station, and correspondence information between the spreading code and the combination of the reception power or the signal interference ratio of the pilot signal at the mobile station with the preamble transmission power of the mobile station.

A transmission control method of implementing radio communication based on code division multiplexing between a base station configured to transmit a pilot signal at a predetermined transmission power and a mobile station configured to transmit a preamble to the base station prior to a start of transmission/reception of data, the transmission control method comprising:

• a spreading step wherein the mobile station determines a spreading code corresponding to any one of the reception power or the signal interference ratio about the pilot signal at the mobile station, the preamble transmission power of the mobile station, and the combination of the reception power or the signal interference ratio of the pilot signal at the mobile station with the preamble transmission power of the mobile station, based on any one of correspondence information between the spreading code used for the preamble and, the reception power or the signal interference ratio of the pilot signal at the mobile station, correspondence information between the spreading code and the preamble transmission power of the mobile station, and correspondence information between the spreading code and the combination of the reception power or the signal interference ratio of the pilot signal at the mobile station with the preamble transmission power of the mobile station, and the mobile station spreads the preamble with the determined spreading code;
• a preamble transmitting step wherein the mobile station transmits the preamble after the spreading process to the base station;
• and
• a rate determining step wherein the base station determines at least one of a transmission power and a downlink transmission rate for a signal directed to the mobile station, and an uplink transmission rate for transmission of information from the mobile station, corresponding to at least the spreading code, based on any one of correspondence information between the spreading code used for the preamble and, the reception power or the signal interference ratio of the pilot signal at the mobile station, correspondence information between the spreading code and the preamble transmission power of the mobile station, and correspondence information between the spreading code and the combination of the reception power or the signal interference ratio of the pilot signal at the mobile station with the preamble transmission power of the mobile station.

A mobile station control program to be executed by a computer provided in a mobile station configured to perform radio communication based on code division multiplexing with a base station which transmits a pilot signal at a predetermined transmission power, and to transmit a preamble to the base station prior to a start of transmission/reception of data,

• the mobile station storing correspondence information between a spreading code used for the preamble, and a reception power or a signal interference ratio of the pilot signal at the mobile station, correspondence information between the spreading code and a preamble transmission power of the mobile station, or correspondence information between the spreading code and a combination of a reception power or a signal interference ratio of the pilot signal at the mobile station with a preamble transmission power of the mobile station, the mobile station control program comprising:
• a spreading step of spreading the preamble with the spreading code corresponding to the reception power or the signal interference ratio of the pilot signal at the mobile station, the preamble transmission power of the mobile station, or the combination of the reception power or the signal interference ratio of the pilot signal at the mobile station with the preamble transmission power of the mobile station, based on the correspondence information stored;
• and
• a transmitting step of transmitting the preamble after the spreading step to the base station.