Wireless communication system, its base station and mobile station, communication synchronization management method and timer control program therefor

Abstract

A wireless communication system is provided for reducing the probability that latency before data transmission increases when a mobile station that is actually in sync is judged to be out of sync. A base station causes the timing calculation part to calculate the timing advance (TA) of a transmit timing from the m th mobile station; causes the timer adaptive control part to obtain the traveling speed or the time variation in TA of the m th mobile station and, adaptively determines and outputs as the timer update information the length of the m th first timer within an M number in total of synchronization timers and the length of the second timer of the m th mobile station and update the length of the m th first timer; and transmits from the downlink transmission part a downlink signal which contains timer update information.

What is claimed is: 
     
         1 . A base station of a wireless communication system which performs communication between a mobile station and the base station, the base station comprising:
 a timer unit which sets a period for judging whether an uplink signal from the mobile station is synchronized; and   a timer control unit which determines the set period for each of   
     
     
         2 . The base station of  claim 1 , wherein the base station notifies said set period via a message which is related to a RRC connection. 
     
     
         3 . A mobile station of a wireless communication system which performs communication between the mobile station and a base station, the mobile station comprising:
 a unit which judges whether an uplink signal to the base station is synchronized based on a set period which is determined for each of a plurality of mobile stations and notified to each of the mobile stations.   
     
     
         4 . The mobile station of  claim 3 , wherein the mobile station received the set period via a message which is related to a RRC connection. 
     
     
         5 . A method executed by at least one processor of controlling a base station of a wireless communication system which performs communication between a plurality of mobile stations and the base station, the method comprising:
 setting a period for judging whether an uplink signal from one of the mobile stations is synchronized; and   determining the set period for each of the mobile stations and notifies the set period to each of the mobile stations.   
     
     
         6 . A method executed by at least one processor of controlling a mobile station of a wireless communication system which performs communication between the mobile station and a base station, the method comprising:
 judging whether an uplink signal to the base station is synchronized based on a set period which is determined for each of a plurality of mobile stations and notified to each of the mobile stations.   
     
     
         7 . A wireless communication system which performs communication between a mobile station and a base station, wherein the base station comprises:
 a timer unit which sets a period for judging whether an uplink signal from the mobile station is synchronized;   a timer control unit which determines the set period for each of a plurality of mobile stations and notifies the set period to each of the mobile stations; and   wherein the mobile station comprises:
 a unit which judges whether an uplink signal to the base station is synchronized based on a set period which is determined for each of the mobile stations and notified to each of the mobile stations. 
   
     
     
       8. A method of a User Equipment (UE), the method comprising:
 receiving a first timer value of a timer and applying the first timer value,
 wherein the timer is used for uplink time alignment, and 
 wherein the first timer value is common to one or more UEs in a cell; 
   receiving a second timer value of the timer,
 wherein the second timer value is received after the first timer value is applied, and 
 wherein the second timer value is transmitted from a base station to the UE dedicatedly; 
   applying a Timing Advance Command and restarting the timer with the second timer value, in a case where the Timing Advance Command is received; and   sending one or more uplink signals to the base station.   
     
     
       9. The method according to  claim 8 , wherein the first timer value is included in system information. 
     
     
       10. The method according to  claim 8 , wherein the first timer value is included in system information broadcast to the UEs. 
     
     
       11. The method according to  claim 8 , wherein the second timer value is included in a message related to an RRC connection. 
     
     
       12. The method according to  claim 8 , wherein the timer with the second timer value is used to determine whether an uplink can be synchronized or not. 
     
     
       13. The method according to  claim 8 , wherein the timer with the second timer value is used to determine whether an uplink can be synchronized or not, and
 wherein the uplink is considered synchronized when the timer with the second timer value is running and the uplink is considered non-synchronized otherwise.   
     
     
       14. A User Equipment (UE) comprising:
 a memory; and   a processor coupled with the memory,   wherein the processor is configured to:
 receive a first timer value of a timer and apply the first timer value, wherein the timer is used for uplink time alignment, and wherein the first timer value is common to one or more UEs in a cell; 
 receive a second timer value of the timer, wherein the second timer value is received after the first timer value is applied, and wherein the second timer value is transmitted from a base station to the UE dedicatedly; 
 apply a Timing Advance Command and restart the timer with the second timer value, in a case where the Timing Advance Command is received; and 
 send one or more uplink signals to the base station. 
   
     
     
       15. The UE according to  claim 14 , wherein the first timer value is included in system information. 
     
     
       16. The UE according to  claim 14 , wherein the first timer value is included in system information broadcast to the UEs. 
     
     
       17. The UE according to  claim 14 , wherein the second timer value is included in a message related to an RRC connection. 
     
     
       18. The UE according to  claim 14 , wherein the timer with the second timer value is used to determine whether an uplink can be synchronized or not. 
     
     
       19. The UE according to  claim 14 , wherein the timer with the second timer value is used to determine whether an uplink can be synchronized or not, and
 wherein the uplink is considered synchronized when the timer with the second timer value is running and the uplink is considered non-synchronized otherwise.