Communication system for reducing congestion

1. A communication system, which comprises a base station device connected to a core network and a plurality of terminal device groups including communication terminal devices connected to said base station device so as to perform radio communication therewith, wherein

said base station device transmits, to a communication terminal device to be called, a paging message including an equipment identity indicating said communication terminal device,

said communication terminal device starts, upon reception of the paging message including the equipment identity indicating said communication terminal device from said base station device, communication with said base station device,

said terminal device groups includes a group of machine type communication (MTC) devices and a group of non-MTC devices,

a maximum number of equipment identities allowed to be included within said paging message is set for the group of MTC devices,

in a case where a number MTC devices is relatively large, the maximum number of equipment identities is set to a relatively large value, and

in a case where the number MTC devices is relatively small, the maximum number of equipment identities is set to a relatively small value.

2. The communication system according claim 1 , wherein said paging message includes data to be provided to said communication terminal device.

3. The communication system according to claim 1 , wherein a maximum number of equipment identities allowed to be included within said paging message is set for the group of non-MTC devices.

4. The communication system according to claim 1 , wherein a higher priority is given for paging non-MTC devices.

5. A communication system, which comprises a base station device connected to a core network and a plurality of terminal device groups including communication terminal devices connected to said base station device so as to perform radio communication therewith, wherein

said base station device transmits, to a communication terminal device to be called, a paging message including a calling indicator indicating that said communication terminal device is being called,

said communication terminal device starts, upon reception of the paging message including the calling indicator indicating that said communication terminal device is being called, communication with said base station device,

said terminal device groups includes a group of machine type communication (MTC) devices and a group of non-MTC devices,

the paging message includes a paging record list including equipment identifiers for a plurality of non-MTC devices, and

the calling indicator indicates that an MTC device is being called.

6. The communication system according to claim 5 , wherein said paging message includes data to be provided to said communication terminal device.

7. The communication system according to claim 5 , wherein the calling indicator indicates that a plurality of MTC-devices are being called.

8. The communication system according to claim 7 , wherein the calling indicator does not contain identity information of the MTC-devices.

9. The communication system according to claim 5 , wherein the calling indicator includes a group indicator indicating that a plurality of communication terminal devices are being called.

10. The communication system according to claim 9 , wherein the group indicator is used to determine a paging frame and a paging occasion.

11. A communication system, which comprises a base station device connected to a core network and a plurality of terminal device groups including communication terminal devices connected to said base station device so as to perform radio communication therewith, wherein

said base station device transmits, to a communication terminal device to be called, a paging message notifying calling,

said communication terminal device starts, upon reception of said paging message addressed to the own device from said base station device, communication with said base station device, and

when said paging message is transmitted to the plurality of communication terminal devices included in the different terminal device groups, said paging message is transmitted to each of said terminal device groups over a different radio frame,

said terminal device groups includes a group of machine type communication (MTC) devices and a group of non-MTC devices, and

said paging message is transmitted to the MTC devices over a sub-frame, within a radio frame, different from a sub-frame, within the radio frame, that said paging message is transmitted to the non-MTC devices.

12. The communication system according to claim 11 , wherein said paging message includes data to be provided to said communication terminal device.

13. A communication system, which comprises a base station device connected to a core network and a plurality of terminal device groups including communication terminal devices connected to said base station device so as to perform radio communication therewith, wherein

said base station device transmits, to a communication terminal device, data to be provided to said communication terminal device, allocation information for a radio resource for the data, and information for notifying whether or not said data has been generated, and

said base station masks the information for notifying whether or not said data has been generated and the allocation information for the radio resource with a radio network temporary identity for the information and maps the information and the allocation information to a physical downlink control channel.

14. A communication system, which comprises a base station device connected to a core network and a plurality of terminal device groups including communication terminal devices connected to said base station device so as to perform radio communication therewith, wherein

if a predetermined disconnection condition is satisfied after a predetermined equipment-side-process is performed between a communication terminal device and said base station device, said base station device chooses to disconnect the communication with said communication terminal device,

if a prediction condition of predicting that said base station device has chosen to disconnect the communication with said communication terminal device is satisfied, said communication terminal device performs a process for establishing communication with said base station device without knowing whether or not said process for establishing communication with said base station device is needed,

the prediction condition includes a threshold for judging whether or not the process for establishing communication is to be performed or an indicator indicating whether or not the process for establishing communication is to be performed, and

the prediction condition is notified to the communication terminal device by the base station device in advance of the base station device choosing to disconnect the communication with said communication terminal device.

15. The communication system according to claim 14 , wherein

when the prediction condition includes the threshold, the threshold is a time period, and

said communication terminal device performs the process for establishing communication based upon a comparison of a period of time between an end of the predetermined equipment-side-process and a next transmission.

16. The communication system according to claim 15 , wherein said communication terminal device performs the process for establishing communication when the period of time is equal to or more than the time period.

17. The communication system according to claim 15 , wherein said communication terminal device does not perform the process for establishing communication when the period of time is equal to or less than the time period.

18. The communication system according to claim 15 , wherein

said communication terminal device performs the process for establishing communication when the period of time is more than the time period, and

said communication terminal device does not perform the process for establishing communication when the period of time is less than the time period.