MOBILE COMMUNICATION METHOD AND EXCHANGE

• US 20100279692A1
• Filed: 10/02/2008
• Published: 11/04/2010
• Est. Priority Date: 10/02/2007
• Status: Active Grant

• Current Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Original Assignee: NTT Docomo Incorporated (Nippon Telegraph and Telephone Corporation)
• Inventors: Hapsari, Wuri Andarmawanti, Ishii, Minami
• Granted Patent: US 8,326,300 B2
• Time in Patent Office: Days
• US Class Current: 455/436
• CPC Class Codes: H04W 36/0011 for data sessions of end-to-end connection
• CPC Class Codes: H04W 36/02 Buffering or recovering information during reselection ; Modification of the traffic flow during hand-off

Abstract

A mobile communication method according to the present invention includes the steps of: transmitting, from a NAS function to an S1-AP function, a NAS-PDU; transmitting, from the S1-AP function to the NAS function, a retransmission request for the NAS-PDU, when receiving a notification, which indicates completion of a handover of a mobile station (UE), from a handover target radio base station (eNB), after receiving an S1-AP response message, *which indicates that transfer of the NAS-PDU to the mobile station (UE) through a radio interface has failed, from the handover source radio base station (eNB); and retransmitting, from the NAS function to the S1-AP function, the NAS-PDU, in response to the retransmission request.

Claims

1. A mobile communication method in which, during handover of a mobile station, an exchange including a first protocol function to function as a first protocol and a second protocol function to function as a second protocol being a lower layer than the first protocol transmits a second protocol message containing a first protocol message to radio base stations each including a second protocol function to function as the second protocol, and each of the radio base stations transmits the first protocol message to the mobile station including a first protocol function to terminate the first protocol, the mobile communication method comprising the steps of:

transmitting, from the first protocol function of the exchange to the second protocol function of the exchange, a first protocol layer message;

transmitting, from the second protocol function of the exchange to a handover source radio base station, the second protocol message containing the first protocol message;

transmitting, from the second protocol function of the exchange to the first protocol function of the exchange, a retransmission request for the first protocol layer message, when receiving a notification, which indicates completion of the handover of the mobile station, from a handover target radio base station, after receiving a second protocol response message, which indicates that transfer of the first protocol message to the mobile station through a radio interface has failed, from the handover source radio base station;

retransmitting, from the first protocol function of the exchange to the second protocol function of the exchange, the first protocol layer message, in response to the retransmission request; and

retransmitting, from the second protocol function to the handover target radio base station, the second protocol message containing the first protocol message.

2. The mobile communication method according to claim 1, further comprising the steps of:

starting, at the first protocol function of the exchange, a retransmission timer used to determine a retransmission timing of the first protocol layer message, when transmitting the first protocol layer message to the second protocol function of the exchange; and

resetting, at the first protocol function of the exchange, the retransmission timer in response to a notification from the second protocol function of the exchange.

3. A mobile communication method in which, during handover of a mobile station, an exchange including a first protocol function to function as a first protocol and a second protocol function to function as a second protocol being a lower layer than the first protocol transmits a second protocol message containing a first protocol message to radio base stations each including a second protocol function to function as the second protocol, and each of the radio base stations transmits the first protocol message to the mobile station including a first protocol function to terminate the first protocol, the mobile communication method comprising the steps of:

transmitting, from the first protocol function of the exchange to the second protocol function of the exchange, a first protocol layer message;

transmitting, from the second protocol function of the exchange to a handover source radio base station, the second protocol message containing the first protocol message; and

retransmitting, from the second protocol function of the exchange to a handover target radio base station, the second protocol message containing the first protocol message, when receiving a notification, which indicates completion of the handover of the mobile station, from the handover target radio base station, after receiving a second protocol response message, which indicates that transfer of the first protocol message to the mobile station through a radio interface has failed, from the handover source radio base station.

4. The mobile communication method according to claim 3, further comprising the steps of:

starting, at the first protocol function of the exchange, a first retransmission timer used to determine a retransmission timing of the first protocol layer message, when transmitting the first protocol layer message to the second protocol function of the exchange;

transmitting, from the second protocol function of the exchange to the first protocol function of the exchange, a notification indicating the completion of the handover of the mobile station, when receiving the notification from the handover target radio base station, after receiving the second protocol response message, which indicates that the transfer of the first protocol message to the mobile station through the radio interface has failed, from the handover source radio base station; and

resetting, at the first protocol function of the exchange, the first retransmission timer in response to the notification from the second protocol function of the exchange.

5. The mobile communication method according to claim 3, further comprising the steps of:

starting, at the second protocol function of the exchange, a second retransmission timer used to determine a retransmission timing of the second protocol layer message, when transmitting the second protocol layer message to the handover source radio base station; and

resetting, at the second retransmission timer, receiving a notification, which indicates the completion of the handover of the mobile station, from the handover target radio base station, after receiving the second protocol response message, which indicates that the transfer of the first protocol message to the mobile station through the radio interface has failed, from the handover source radio base station.

6. The mobile communication method according to claim 3, wherein

the handover source radio base station uses a sequence number in the second protocol to specify the second protocol message whose transfer has failed.

7. The mobile communication method according to claim 3, wherein

the handover source radio base station uses a sequence number in a protocol of a lower layer than the second protocol to specify the second protocol message whose transfer has failed.

8. An exchange to be used in a mobile communication system in which, during handover of a mobile station, the exchange including a first protocol function to function as a first protocol and a second protocol function to function as a second protocol being a lower layer than the first protocol transmits a second protocol message containing a first protocol message to radio base stations each including a second protocol function to function as the second protocol, and each of the radio base stations transmits the first protocol message to the mobile station including a first protocol function to terminate the first protocol, wherein

the first protocol function of the exchange is configured:

to transmit a first protocol layer message to the second protocol function of the exchange, and to store the first protocol layer message in a buffer; and

to retransmit the first protocol layer message stored in the buffer to the second protocol function of the exchange, in response to a retransmission request for the first protocol layer message received from the second protocol function of the exchange; and

the second protocol function of the exchange is configured;

to transmit a second protocol message containing the first protocol message received from the first protocol function of the exchange to a handover source radio base station; and

to transmit the retransmission request to the first protocol function of the exchange, when receiving a notification, which indicates the completion of the handover of the mobile station, from a handover target radio base station, after receiving a second protocol response message, which indicates that transfer of the first protocol message to the mobile station through a radio interface has failed, from the handover source radio base station; and

to retransmit the second protocol message containing the first protocol message received from the first protocol function of the exchange to the handover target radio base station.

9. The exchange according to claim 8, wherein

the first protocol function of the exchange is configured to start a retransmission timer used to determine a retransmission timing of the first protocol layer message, when transmitting the first protocol layer message to the second protocol function of the exchange;

and

the first protocol function of the exchange is configured to reset the retransmission timer in response to a notification from the second protocol function of the exchange.

10. An exchange to be used in a mobile communication method in which, during handover of a mobile station, the exchange including a first protocol function to function as a first protocol and a second protocol function to function as a second protocol being a lower layer than the first protocol transmits a second protocol message containing a first protocol message to radio base stations each including a second protocol function to function as the second protocol, and each of the radio base station transmits the first protocol message to the mobile station including a first protocol function to terminate the first protocol, wherein

the first protocol function of the exchange is configured to transmit a first protocol layer message to the second protocol function of the exchange;

and

the second protocol function of the exchange is configured;

to transmit a second protocol message containing the first protocol message received from the first protocol function of the exchange to a handover source radio base station, and to store the second protocol message in a buffer; and

to retransmit the second protocol message stored in the buffer to a handover target radio base station, when receiving a notification, which indicates completion of the handover of the mobile station, from the handover target radio base station, after receiving a second protocol response message, which indicates that transfer of the first protocol message to the mobile station through a radio interface has failed, from the handover source radio base station.

11. The exchange according to claim 10, wherein

the first protocol function of the exchange is configured to start a first retransmission timer used to determine a retransmission timing of the first protocol layer message, when transmitting the first protocol layer message to the second protocol function of the exchange;

and

the second protocol function of the exchange is configured to transmit a notification indicating the completion of the handover of the mobile station, to the first protocol function of the exchange, when receiving the notification from the handover target radio base station, after receiving the second protocol response message, which indicates that the transfer of the first protocol message to the mobile station through the radio interface has failed, from the handover source radio base station; and

the first protocol function of the exchange is configured to reset the retransmission timer in response to a notification from the second protocol function of the exchange.

12. The exchange according to claim 10, wherein

the second protocol function of the exchange is configured to start a second retransmission timer used to determine a retransmission timing of the second protocol layer message, when transmitting the second protocol layer message to the handover source radio base station;

and

the second protocol function of the exchange is configured to reset the second retransmission timer, when receiving a notification, which indicates the completion of the handover of the mobile station, from the handover target radio base station, after receiving the second protocol response message from the handover source radio base station, the second protocol response message indicating that the transfer of the first protocol message to the mobile station through the radio interface has failed, from the handover source radio base station.