To significantly extend the battery life of a radio terminal while sharing a frequency with another radio system, without providing a DAA function to the radio terminal.
Terminals 40 to 44 transmit data at predetermined time intervals. For example, a signal of the terminal 44 is received by base stations 32 and 33. Of the base stations 32 and 33, the base station 33 that is closer to the terminal 44 is designated as one that is to be in charge of the terminal 44, taking into consideration a state of reception in the past (the number of times of successful reception, etc.). Here, when a signal comes from another radio system that uses the same frequency band, a supervisory station 1 retrieves the terminal 44 that would cause interference from a history stored in a positioning server 50, and transmits to the base station 33 a command to stop transmission to the terminal 44. The terminal 44, when receiving the transmission stop command from the base station 33, stops the transmission.
SAKAMURA TAKESHI
MOROKUMA TATESHI
MIYAZAKI SUKEYUKI
FUJIWARA RYOSUKE
HITACHI LTD
| JP2001298763A | 2001-10-26 | |||
| JP2002135831A | 2002-05-10 | |||
| JP2002354531A | 2002-12-06 | |||
| JP2007166488A | 2007-06-28 | |||
| JP2002158667A | 2002-05-31 |
Tadashi Takahashi