Radio communication system including SDL having transmission rate of relatively high speed

Abstract

A large amount of user information is transmitted with good efficiency by means of a high-speed downlink by making transmission rates of an uplink circuit and a downlink asymmetrical. The radio communication system includes a plurality of base stations, a plurality of terminals, an uplink established between each of the base stations and each of the terminals for the purpose of radio transmission of prescribed information from a terminal to a base station, and a downlink circuit established between each of the terminals and each of the base station for the purpose of radio transmission of prescribed data from a base station to a terminal. This radio communication system has a low-speed transmitting means, provided at the terminal, which transmits a radio signal at a relatively low transmission rate to an above-noted base station via the above-noted uplink, a low-speed receiving means, provided at the base station, which receives a radio signal sent at a relatively low transmission rate from one terminal via the uplink, a high-speed transmitting means, provided at the base station, which transmits a radio signal at a relatively high transmission rate to an above-noted terminal via the above-noted downlink, and a high-speed receiving means, provided at the terminal, which receives a radio sent at a relatively high transmission rate from the base station via the downlink.

1. A radio communication system including at least one base station, and a plurality of terminals, said radio communication system comprising:
 an uplink which performs radio transmission of data at a first transmission rate;  
 a low-speed down link which performs radio transmission of the data at a the first transmission rate;  
 a high-speed downlink which performs radio transmission of the data at a second transmission rate which is higher than the first transmission rate;  
 a first low-speed transmitter, provided at said terminal, which transmits a first radio signal at the first transmission rate to said base station via said uplink;  
 a first low-speed receiver, provided at the base station, which receives the first radio signal, which sent at the first transmission rate, from said terminal via said uplink;  
 a high-speed transmitter, provided at said base station, which transmits a second radio signal at the second transmission rate to said terminal via said high-speed downlink;  
 a high-speed receiver, provided at said terminal, which receives the second radio signal at the second transmission rate from said base station via said high-speed downlink;  
 a second low-speed transmitter, provided at said base station, which transmits a third radio signal at the first transmission rate to said terminal via said low-speed downlink; and  
 a second low-speed receiver, provided at said terminal, which receives the third radio signal at the first transmission rate from said base station via said low-speed downlink;  
 wherein said uplink and said low-speed downlink establish radio transmission at a first frequency, and said high-speed down link establishes radio transmission at a second frequency which is higher than said first frequency; and  
   wherein at least said high - speed downlink and said low - speed uplink form an asymmetric communication path between said base station and said terminal, in which said high - speed uplink is used by said second radio signal at a relatively high transmission rate, and said low - speed uplink is used by said first radio signal at a relatively low transmission rate.    
 
     
     
       2. A radio communication system including at least one base station, and a plurality of terminals, said radio communication system comprising:
   an uplink which performs radio transmission of data at a first transmission rate;        a low - speed downlink which performs radio transmission of data at the first transmission rate;        a high - speed downlink which performs radio transmission of data at a second transmission rate which is higher than the first transmission rate;        a first low - speed transmitter, provided at said terminal, which transmits a first radio signal at the first transmission rate to said base station via said uplink;        a first low - speed receiver, provided at said base station, which receives the first radio signal which is transmitted at the first transmission rate from said terminal via said uplink;        a high - speed transmitter, provided at said base station, which transmits a second radio signal at the second transmission rate to said terminal via said high - speed downlink;        a high - speed receiver, provided at said terminal, which receives the second radio signal at the second transmission rate from said base station via said high - speed downlink;        a second low - speed transmitter, provided at said base station, which transmits a third radio signal at the first transmission rate to said terminal via said low - speed downlink; and        a second low - speed receiver, provided at said terminal, which receives the third radio signal at the first transmission rate from said base station via said low - speed downlink;        wherein said uplink and said low - speed downlink establish radio transmission at a first frequency, and said high - speed downlink establishes radio transmission at a second frequency which is higher than said first frequency; and        wherein at least said high - speed downlink and said low - speed uplink form an asymmetric communication path between said base station and said terminal, in which said high - speed uplink is used by said second radio signal at a relatively high transmission rate, and said low - speed uplink is used by said first radio signal at a relatively low transmission rate.     
     
     
       3. The radio communication system according to  claim 2 , wherein
   said uplink and said low - speed downlink, which establish the radio transmission at said first frequency, perform radio transmission of the data at the first and third signals, respectively, within a wide communication area; and        said high - speed downlink which establishes the radio transmission at said second frequency, performs radio transmission of the data at the second radio signal in a narrow area.     
     
     
       4. The radio communication system according to  claim 3 , wherein
   said base station transmits at least user information to said terminal by said second low - speed transmitter; and        said terminal transmits at least control information to said base station by said first low - speed transmitter.     
     
     
       5. The radio communication system according to  claim 3 , wherein
   said base station transmits at least one of control information and voice information to said terminal by said second low - speed transmitter.     
     
     
       6. The radio communication system according to  claim 3 , wherein
   said base station transmits to said terminal an identifying signal for identifying the base station itself by said high - speed transmitter; and        said terminal further comprises said high - speed receiver which receives said identifying signal, base station notification means for receiving an optimum base station for a connection on the basis of said identifying signal received by said high - speed receiver, and said first low - speed transmitter transmitting information with respect to said optimum base station which is notified by said base station notification means, to said optimum base station.     
     
     
       7. The radio communication system according to  claim 3 , wherein
   said base station transmits to said terminal an identifying signal for identifying the base station itself by said high - speed transmitter; and        said terminal further comprises said high - speed receiver which receives said identifying signal, base station notification means for notifying an optimum base station for a connection on the basis of said identifying signal received by said high - speed receiver and for further notifying any other optimum base station when the other optimum base station is determined to be an optimum base station rather than the base station during the connection, and said first low - speed transmitter transmitting information with respect to said optimum base station which is notified by said base station notification means, to said optimum base station.     
     
     
       8. The radio communication base station provided in a radio communication system and performing a radio communication with a terminal, comprising:
   a first low - speed receiver which performs a first radio communication with a first low - speed transmitter provided at the terminal by using a first radio frequency signal at a first radio transmission rate;        a high - speed transmitter which performs a second radio communication with a high - speed receiver provided at the terminal, by using a second radio frequency signal different from the first radio frequency signal at a second transmission rate higher than the first radio frequency signal; and        a second low - speed transmitter which performs the first radio communication with a second low - speed receiver provided at the terminal at the first radio transmission rate;        wherein at least said high - speed downlink and said low - speed uplink form an asymmetric communication path between said base station and said terminal, in which said high - speed uplink is used by said second radio frequency signal at a relatively high transmission rate, and said low - speed uplink is used by said first radio frequency signal at a relatively low transmission rate.     
     
     
       9. The radio communication base station according to  claim 8 , wherein
   said base station transmits at least user information to said terminal by said second low - speed transmitter; and        said terminal transmits at least control information to said base station by said first low - speed transmitter.     
     
     
       10. The radio communication base station according to  claim 8 , wherein
   said base station transmits at last one of control information and voice information to said terminal by said second low - speed transmitter.     
     
     
       11. The radio communication base station according to  claim 8 , wherein
   said base station transmits to said terminal an identifying signal for identifying the base station itself by said high - speed transmitter; and        said terminal further comprises said high - speed receiver which receives said identifying signal, base station notification means for notifying an optimum base station for a connection on the basis of said identifying signal received by said high - speed receiver, and said first low - speed transmitter transmitting information with respect to said optimum base station which is notified by said base station notification means, to said optimum base station.     
     
     
       12. The radio communication base station according to  claim 8 , wherein
   said base station transmits to said terminal an identifying signal for identifying the base station itself by said high - speed transmitter; and        said terminal further comprises said high - speed receiver which receives said identifying signal, base station notification means for notifying an optimum base station for a connection on the basis of said identifying signal received by said high - speed receiver and for further notifying any other optimum base station when the other optimum base station is determined to be an optimum base station rather than the base station during the connection, and said first low - speed transmitter transmitting information with respect to said optimum base station which is notified by said base station notification means, to said optimum base station.     
     
     
       13. A radio communication terminal provided in a radio communication system and performing a radio communication with a radio communication base station, comprising:
   a first low - speed transmitter which performs a first radio communication with a first low - speed receiver provided at the base station, by using a first radio frequency signal at a first radio transmission rate;        a high - speed receiver which performs a second radio communication with a high - speed transmitter provided at the base station, by using a second radio frequency signal different from the first radio frequency signal at a second transmission rate higher than the first radio frequency signal; and        a second low - speed receiver which performs the first radio communication with a second low - speed transmitter provided at the base station at the first radio transmission rate;        wherein at least said high - speed downlink and said low - speed uplink form an asymmetric communication path between said base station and said terminal, in which said high - speed uplink is used by said second radio frequency signal at a relatively high transmission rate, and said low - speed uplink is used by said first radio frequency signal at a relatively low transmission rate.     
     
     
       14. The radio communication terminal according to  claim 13 , wherein
   said base station transmits at least user information to said terminal by said second low - speed transmitter; and        said terminal transmits at least control information to said base station by said first low - speed transmitter.     
     
     
       15. The radio communication terminal according to  claim 13 , wherein
   said base station transmits at least one of control information and voice information to said terminal by said second low - speed transmitter.     
     
     
       16. The radio communication terminal according to  claim 13 , wherein
   said base station transmits to said terminal an identifying signal for identifying the base station itself by said high - speed transmitter; and        said terminal further comprises said high - speed receiver which receives said identifying signal, base station notification means for notifying an optimum base station for a connection on the basis of said identifying signal received by said high - speed receiver, and said first low - speed transmitter transmitting information with respect to said optimum base station which is notified by said base station notification means, to said optimum base station.     
     
     
       17. The radio communication terminal according to  claim 13 , wherein
   said base station transmits to said terminal an identifying signal for identifying the base station itself by said high - speed transmitter; and        said terminal further comprises said high - speed receiver which receives said identifying signal, base station notification means for notifying an optimum base station for a connection on the basis of said identifying signal received by said high - speed receiver and for further notifying any other optimum base station when the other optimum base station is determined to be an optimum base station rather than the base station during the connection, and said first low - speed transmitter transmitting information with respect to said optimum base station which is notified by said base station notification means, to said optimum base station.