Paging processing method, user equipment and system

1. A paging processing method, comprising:

sending, by a user equipment, a first routing area update (RAU) message to a serving general packet radio system (GPRS) support node (SGSN);

receiving, by the user equipment, a first RAU reject message from the SGSN; and

starting, by the user equipment, a mobility management back-off timer of the user equipment;

receiving, by the user equipment, a paging message from the SGSN; and

sending, by the user equipment, a second RAU message to the SGSN in response to the paging message when a value of a temporary identity used in next update (TIN) of the user equipment is a globally unique temporary identity (GUTI) and the mobility management back-off timer of the user equipment is under a running state.

2. The method according to claim 1 , wherein the first RAU reject message carries a value of the mobility management back-off timer.

3. The method according to claim 1 , wherein an idle mode signaling reduction (ISR) mechanism is activated for the user equipment.

4. The method according to claim 1 , wherein the first RAU reject message is sent because of an overload of the SGSN.

5. A user equipment, comprising:

a transmitter, configured to send a first routing area update (RAU) message to a serving general packet radio system (GPRS) support node (SGSN);

a receiver, configured to receive a first RAU reject message from the SGSN;

a processor, configured to start a mobility management back-off timer of the user equipment;

wherein the receiver is further configured to receive a paging message from the SGSN; and

wherein the transmitter is further configured to, in response to the paging message, send a second RAU message to the SGSN when a value of a temporary identity used in next update (TIN) is a globally unique temporary identity (GUTI) and the mobility management back-off timer of the user equipment is under a running state.

6. The user equipment according to claim 5 , wherein the first RAU reject message carries a value of the mobility management back-off timer.

7. The user equipment according to claim 5 , wherein an idle mode signaling reduction (ISR) mechanism is activated for the user equipment.

8. The user equipment according to claim 5 , wherein the first RAU reject message is sent because of an overload of the SGSN.

9. A paging processing system, comprising:

a serving general packet radio system (GPRS) support node (SGSN); and

a user equipment;

wherein the user equipment is configured to send a first routing area update (RAU) message to the SGSN, receive a first RAU reject message from the SGSN and start a mobility management back-off timer of the user equipment;

wherein the SGSN is configured to send a paging message to the user equipment, and after receiving a second RAU message from the user equipment, to acquire a bearer context of the user equipment; and

wherein the user equipment is further configured to receive the paging message sent by from the SGSN, and to send the second RAU message to the SGSN in response to the paging message when a value of a temporary identity used in a next update (TIN) of the user equipment is a globally unique temporary identity (GUTI) and the mobility management back-off timer of the user equipment is under a running state.

10. The paging processing system according to claim 9 , wherein the first RAU reject message carries a value of the mobility management back-off timer.

11. The paging processing system according to claim 9 , wherein an idle mode signaling reduction (ISR) mechanism is activated for the user equipment.

12. The paging processing system according to claim 9 , wherein the first RAU reject message is sent because of an overload of the SGSN.