Apparatus and method for controlling device triggering in a mobile communication network

A method for controlling device triggering in a mobile communication system includes registering a default urgent level of a terminal when the terminal is connected, receiving a device trigger register including urgent level information transmitted from an application server, and setting the received urgent level in a packet filter, and comparing, upon reception of a downlink data packet from the application server, a default urgent level and an urgent level of the application server to determine whether to transmit a downlink data notification. The method further includes receiving a device trigger register including wait time information transmitted from an application server, and then setting the received wait time in the packet filter, and buffering during the wait time upon reception of the downlink data packet from the application server, and then determining a downlink data notification transmission upon expiration of the wait time.

TECHNICAL FIELD

The present invention relates to a data packet communication apparatus and method of a mobile communication network and, in particular, to a device-triggering control apparatus and method for connecting to an external server.

BACKGROUND ART

In the mobile communication, device triggering is the means by which a server located outside a Mobile Operation Network indicates necessity of communication such that a terminal connects to the server. The device triggering has to be available both cases when the terminal is in the online state and has data connection and when the terminal is in the online state but has no data connection.

FIG. 1is a diagram illustrating architecture of a mobile operator network interworking with a circuit network for providing Short Message Service (SMS), andFIG. 2is a diagram illustrating a mobile communication network including the packet service network and an application server. Referring toFIGS. 1 and 2, the solution making it possible to fulfilling the requirements of the current device triggering is an SMS-based push service. That is, if the information on the external server through SMS, the terminal which receives the SMS establishes a Packet Data Network (PDN) connection to connect to the external server. However, the SMS-based connection method uses a Circuit Switched network, there is a problem in that the LTE system using only the Packet Switched (PS) network has to interwork with the legacy Circuit Switched network. There is therefore a need of a method for supporting device triggering only with the Packet Switched network without interworking with the Circuit Switched network.

The device triggering in the packet network may causes signaling overhead. That is, if several application servers located at external networks request for device trigger service to communicate small amount of data, this causes frequent state transitions of the terminal, resulting in signaling overhead of the mobile communication network. For example, if a terminal which has received a paging for device triggering of an application connects to an application server to exchanged small amount of data and enters the idle state and, afterward, if the paging for device triggering associated with another application server is received, the terminal transitions to the active state to exchange small amount of data and then transitions to the idle state, repeatedly. The signaling overhead problem is exemplified as shown inFIG. 3.FIG. 3is a graph illustrating an exemplary signaling overhead increment caused by state transition. As shown inFIG. 3, the signaling overhead is the problem caused by the application server using notification for the data terminal (e.g. smartphone)

DISCLOSURE OF INVENTION

Technical Problem

The mobile communication system configures a packet filter for controlling device triggering and controls, when there is any device trigger request, the connection between the external server and the terminal selectively based on the information configured to the packet filter. That is, an embodiment of the present invention proposes a method of configuring, at the mobile communication network, packet filters for device triggering levels or timings per application server and analyzing, when a device trigger request is received from the corresponding application server, the packet filter to determine whether to perform downlink data notification.

An embodiment of the present invention proposes a method of configuring the packet filter of a serving gateway based on tolerant level (or urgent level), wait time, the data packet amount buffered at the serving gateway and/or the load status of MME and analyzing, when device trigging is detected, the packet filter for the corresponding application server to determine whether to send downlink data notification.

Solution to Problem

In accordance with an aspect of the present invention, a device triggering method of a mobile communication system includes registering, when a terminal attaches, a default urgent level of corresponding terminal, receiving a device trigger register including urgent level information from an application server, configuring a packet filter with the urgent level, determining, when a downlink data packet is received, whether to transmit a downlink data notification by comparing a urgent level of the application server with the default urgent level.

At this time, the determining of whether to transmit the downlink data notification includes comparing the urgent level of the application server with the default urgent level, notifying, when the urgent level is higher than the default urgent level, the downlink packet, buffering and transmitting, when the terminal attaches, the data packet to the terminal, and buffering, when the urgent level is lower than the default urgent level, the packet.

In accordance with an aspect of the present invention, a device triggering control method of the mobile communication system receives a device trigger register including wait time information from an application server, configuring a packet filter with the wait time, buffering downlink data packets transmitted by the application server during the wait time, and determining, when the wait time expires, downlink data notification transmission.

The determining of the downlink data notification transmission includes starting, when no buffered data exists in receiving the data packet, a downlink data notification timer, buffering, when buffered data exists, buffers the received data packet, notifying, when the downlink data notification timer expires, the UE of the downlink packet, and transmitting, when the terminal attaches, the buffered data.

In accordance with an aspect of the present invention, a device triggering control apparatus of a mobile communication system includes terminals, application servers which transmit device trigger registers including urgent level information and generate downlink data packets, a serving gateway, and a core network which configures a packet filter of the serving gateway with a default urgent level and urgent levels transmitted by the application servers, comparing, when a downlink data packet is received from an application server, the urgent level of the corresponding application server with the default urgent level to determine whether to transmit a downlink data notification to the terminal.

In accordance with an aspect of the present invention, a device triggering control apparatus of a mobile communication system includes terminals, application servers which transmit device trigger registers including wait time information and generate downlink data packets, a serving gateway, and a core network which configures a packet filter of the serving gateway with the wait times transmitted by the application servers, buffers downlink packets transmitted by the application servers during the wait time, and determine, when the wait time expires, transmitting a downlink data notification.

Advantageous Effects of Invention

The device-triggering control apparatus and method of the present invention processes downlink data packets using the packet filter configured per application server so as to avoid frequent state transitions of the terminal for data packet download and thus reduce signaling overhead of the mobile communication network.

MODE FOR THE INVENTION

Exemplary embodiments of the present invention are described with reference to the accompanying drawings in detail. The same reference numbers are used throughout the drawings to refer to the same or like parts.

In an embodiment of the present invention, the device-triggering apparatus configures the packet filter of the serving gateway (SGW) of the mobile terminal to a level or time for device triggering and, if there is any device trigger request, controls the connection between the external server and the terminal according to the information configured to the packet filter. That is, an embodiment of the present invention proposes a method for configuring packet filter per application server and determining, at the mobile communication network, whether to transmit a downlink data notification based on the analysis of the packet filter when the corresponding application server requests for device trigger.

In an embodiment of the present invention, the packet filter may be configured as follows. First, the present invention proposes a method for configuring the packet filter with the tolerant level (or urgent level) and analyzing, when a device trigger is received, the packet filter of the corresponding application server to determine whether to transmit downlink data notification (first embodiment). Here, the urgent level may correspond to priority. Secondly, the present invention proposes a method for configuring the packet filter with the wait time and analyzing, when a device trigger is received, the packet filter of the corresponding application server to determine whether to transmit downlink data notification (second embodiment). Thirdly, the present invention proposes a method for configuring the packet filter with a plurality of tolerant levels (or urgent levels) and the wait times corresponding to the respective levels and analyzing, when a device trigger is received, the packet filter of the corresponding application server to determine whether to transmit downlink data notification. Fourthly, the present invention proposes a method for configuring the packet filter with the data buffer amount of the serving gateway (SGW) and analyzing, when a device trigger is received, the packet filter of the corresponding application server to determine whether to transmit the downlink data notification. Fifthly, the present invention proposes a method for configuring the packet filter with the load status of the MME and analyzing, when a device trigger is received, the packet filter of the corresponding application server to determine whether to transmit the downlink data notification. In the following, the description is mainly directed to the first embodiment of the first method and the second embodiment of the second method.

A description is made of the packet filter configuration method according to the first embodiment of the present invention.

The Long Term Evolution (LTE) network supports the always-on connectivity of the attached terminal. Accordingly, the terminal maintains, event in the idle state, S5bearer (bearer between SGW and PGW) of the PDN connection and thus, if any downlink data addressed to the terminal is received, the SGW buffers the data and sends the terminal a downlink data notification to trigger paging. If the terminal transitions to the active state upon receipt of it, the mobile communication system forwards the received data to the terminal. At this time, the method of the first embodiment configures the urgent level of the acknowledgement corresponding to the downlink data while using the buffering function of the SGW. If the terminal is in the idle state in this state, the mobile communication system buffers the downlink data below a predetermined level and, if the downlink data exceeds the predetermined level, transmits a paging so as to process the acknowledgements to the server at a time when the operation state of the terminal transitions to the active state.

FIG. 4is a diagram illustrating architecture of a mobile communication system according to an embodiment of the present invention. Referring toFIG. 4, the application server470generates a device trigger registration request message including a device identifier (ID), a source address and port, and packet filter configuration information and transmits downlink data. Here, the device ID may be an external ID. The application Interworking function (IWF)460receives the device trigger registration request message from the application server470and sends the Policy and Charging Rules Function (PCRF)450the Policy and Charging Rule provision (PCRF) information including APN, source address and port, and packet configuration information received from the IWF460. The PCRF450communicates with the Packet Data Network (PDN) Gateway (PGW)440to configure the default packet filter and sends the PGW440the PCRF information including the APN, source address and port, and packet configuration information received from the application IWF460. The PGW440communicates the default packet filter to be configured at the SGW430and the packet filter information of the application server470with the PCRF450. The SGW430configures the default packet filter and the packet filter of the application server470, buffers the downlink packets from the application server470, and analyzes the packet filter of the application server470and the default packet filter toe notify the UE of presence/absence of downlink packet. The evolved Node B (eNB)420establishes a radio link with the User Equipment (UE)410and controls the radio communication between the UE410and the mobile communication system including the SGW430.

Here, the PGW440, SGW430, and MME (not shown) are the entities of the core network.

In the above-structured mobile communication system, the application IWF460receives the device trigger registration request including the UE ID and packet configuration information from the external application server470and forwards it to the PGW440via the PCRF450. Then the SGW430configures the packet filter with the information on the application server470(src addr, src port) and packet filter information (urgent level, wait time, etc.) to adjust the state transition of the UE410. Here, the wait time may be a valid period.

FIG. 5is a flow diagram illustrating a procedure of controlling device trigger by configuring packet filter with urgent level according to the first embodiment of the present invention.

Referring toFIG. 5, the UE410may request for connection or PDN connection at step501. In this state, the PGW440sends the PCRF450an IP Connectivity Access Network (CAN) session establishment indication, which includes UE Id, APN, IP address, etc., for policy and QoS configuration at step503.

Upon receipt of the IP CAN session Establishment indication from the

PGW440at step503, the PCRF450acknowledges the receipt of the IP CAN session Establishment with Policy and Charging Control (PCC) rule including service data flow template and default urgent level. That is, in the first embodiment of the present invention, the RRC rule is transmitted with the configuration of the default urgent level of the corresponding PDN connection. At this time, the default urgent level may be configured per PDN connection or bearer level. The default urgent level information is installed at the SGW430but not transferred to the UE410.

In the above state, the application server470may configure the urgent level for use in device triggering. In this case, the Application Server470generates the device trigger registration request message (device trigger register) with the parameters including address (src_addr) and port (src_port) used by the server for communication with the UE and the urgent level value of the communication between the corresponding server and the UE to register the device trigger with the application IWF460. At this time, the UE id may be a public id such as URI, FQDN, and MSIDSN. Then the application IWF460sends the Home Subscriber Server (HSS) a request including the device id as a parameter to check the International Mobile Subscriber Identity (IMSI) as the id used by MNO at step513. Then the HSS sends the application IWF460a response device ID such as IMSI and subscription information at step515. That is, the application IWF460acquires APN subscription information in addition to IMSI.

Afterward, the application IWF460sends the PCRF450the application/service information including address and port of the application server (src_addr and src_port), urgent level, and APN used by the UE in communication with the corresponding server based on the IMSI at step517. At this time, the APN is selected based on the APN subscription information or operator configuration. The PCRF450sends the PGW440a PCC rule of the corresponding PGW which has been updated based on the information received from the application IWF460at step523, the PCC rule including APN, src_addr, src_port, and urgent level. The PCRF450sends the application IWF460the Ack at step519, and the application IWF460forwards the ACK to the application server470at step521.

The PGW440sends the SGW430a service data flow including the urgent level received from the PCRF at step525(update bearer request (service data flow (src_addr, src_port, urgent level)) to SGW only), and the SGW430installs this (store add/update packet filter the updated service data flow) at step527. Here, since the urgent level is the information which is not transmitted to the UE, the change of the urgent level information is terminated at the SGW. After configuring the packet filter with the urgent level of the application server470as described above, the SGW430sends the PGW440an update bearer response at step529, and the PGW440sends the PCRF450the ack message at step513.

After configuring the packet filter with the urgent level of the application server470at the SGW430, if downlink data packet occurs at the application server470, the downlink data packet is transmitted to the SGW430at step533. Upon receipt of the downlink data packet, the SGW430checks whether the urgent level of the corresponding service data flow is higher than a default urgent level (check if the urgent level of src_addr, src_port is greater than default urgent level) and processes the corresponding data packet according to the comparison result at step535. If the urgent level is lower than the default urgent level installed at step505, the SGW430does not send the downlink data notification to the corresponding MME and buffers the received data packet at step535. Afterward, in order to transmit the buffered data to the UE410at the timing of the default urgent level, a paging is transmitted. In an exemplary case of using a default urgent level timer, the default urgent level timer starts at the receipt of the data packet and, if the timer expires, the SGW pages the UE410to transmit the buffered data packet. Otherwise if the urgent level of the received packet is higher that the default urgent level installed at step505, the SGW430sends the corresponding MME a downlink data notification to trigger paging. If the connection is established, the mobile communication system transmits the received data packets to the UE. At this time, if there is buffered data packet, the buffered data packets are transmitted together.

Here, the urgent level may be reconfigured when the application server470performs the device trigger registration again since the initial configuration.

As described above, the urgent level of the downlink data is configured while using the buffering function of the SGW430in the first embodiment of the present invention. if the UE in the idle state receives the downlink packet, the mobile communication system compares the urgent level registered by the application server with the default urgent level of the UE and, if it is equal to or lower than the urgent level, buffers the downlink data and, otherwise if it is higher than the default level, pages the UE to transition to the active state and transmits the downlink packet.

The second embodiment of the present invention proposes a method for configuring the packet filter with the wait time and processing downlink data packet based thereon. That is, the second embodiment of the present invention relates to the method of configuring the wait time instead of the tolerant level (urgent). In the device trigger registration, the application server470set the wait time to the maximum value available after the trigger. If the application server470transmits downlink data after the wait time configuration, the SGW430operates as follows depending on the state of the corresponding UE. First, if there is no data buffered at the SGW430, the SGW430configures the wait time of the arrived data as the timer for transmitting the downlink data notification. Secondly, if there is data buffered at the SGW430and if the residual time of the configured downlink data notification timer is shorter than the wait timer of the arrived data, the SGW430buffers the corresponding data and, otherwise if the residual time of the configured downlink data notification timer is longer than the wait timer of the arrived data, resets the timer to the wait time of the corresponding timer and buffers the data. Thirdly, if the downlink data notification timer expires, the SGW430sends the MME the downlink data notification to trigger paging.

FIG. 6is a flow diagram illustrating a procedure of configuring the packet filter of the SGW430with the wait timer and processing the data packet received since then according to the second embodiment of the present invention.

Referring toFIG. 6, if the UE requests for Attach or PDN connection at step601, the PGW440sends the PCRF450an IP CAN session establishment indication message including UE id, APN, and IP address for configuring policy at step603. Upon receipt of the IP CAN session establishment indication from the PGW440, the PCRF450sends a PCC Rule in reply at step605.

The application server470generates the device trigger using the parameters including the address and port information used in communication with the UE, wait time value of the communication between the corresponding server and the terminal, and the UE id and registers the device trigger with the application IWF460at step611. The UE id used at this time may be a public id such as URI, FQDN, and MSIDSN. Then the application IWF460sends the HSS a request including the device id as a parameter to check the IMSI as the id used by MNO at step613and receives IMSI and APN subscription information from the HSS at step615

Afterward, the application IWF460generates application/service information including the application server address and port, wait time, and APN used by the UE in communication with the corresponding server and registers the information with the PCRF450at step617. At this time, the APN is selected based on the APN subscription information or operator configuration. The PCRF450generates the PCC rule updated based on the information received from the application IWF460and sends the PGW440the PCC rule at step623. The PCRF450sends the application IWF460an ack message at step619, and the application IWF460forwards the ack message to the application server470at step621.

The PGW440sends the SGW430a service data flow including the wait time received from the PCRF450(update bearer request (service data (src_add, src_port, wait time) to SGW only) at step625, and the SGW430updates the packet filter with the received update service data (store add/update packet filter the updated service add flow) at step627. Here, since the wait time is the information which is not transmitted to the UE, the change of the wait time information is terminated at the SGW. Afterward, the SGW430sends the PGW440an update bearer response at step629, and the PGW440sends the PCRF450the ack message at step633.

If a downlink data packet occurs at the application server470after updating the packet filter of the SGW430, the SGW430receives the downlink data packet at step633. Upon receipt of the downlink data packet, the SGW430checks and processes the wait time configured for the corresponding service data flow at step635. At this time, if there is no data buffered at the SGW430, sets the downlink data notification timer to the wait time (No buffered data: set timer to wait time of arrived data). If there is data buffered, the SGW430processes the received data packet as follows. First, if the residual time of the configured downlink data notification timer is shorter than the wait timer of the arrived data, the SGW430buffers the corresponding data (remaining timer<wait timer→just buffering data). Secondly, if the residual time of the configured downlink data notification timer is longer than the wait timer of the arrived data, the SGW430resets the downlink data notification timer to the wait time of the corresponding data and buffers data (remaining timer>wait timer→reset downlink data notification timer). If the downlink data notification timer configured at the SGW430expires, the SGW430sends the MME the downlink data notification. Here, the wait time may be rest when the application server470performs the device trigger registration again since the initial setting.

In an embodiment of the present invention, the packet filter of the SGW430may be configured with the features of the first and second embodiments. In this case, the application server470generates device trigger registers for configuring a plurality of urgent levels and wait timers corresponding to the levels, and the SGW430configures the packet filters with the urgent levels and corresponding wait times received through the above procedure. The level for processing the downlink data packet may be selected by the application server470or the SGW430. In the case that the application server470processes, the application server470sends the downlink packet data along with the level information.

When receiving the downlink data packet, the SGW430may determine whether to send the device triggering based on the load state of the MME. That is, the SGW430determines whether to deliver data packet based on the load at the MME and the level of the UE to which the data packet is addressed. For example, if the load of the MME is great, the data packet transmission may be permitted to the UE with high QoS level. The SGW430also may determine whether to send the device triggering depending on the size of the buffered data packet. That is, the SGW430buffers the data packets and, if the amount of the data packets exceeds a predetermined size, triggers the corresponding UE to control the connection of the UE. In an embodiment of the present invention, it is possible to use at least two packet filter configuration methods selectively in configuring the packet filter of the SGW430.

Although preferred embodiments of the invention have been described using specific terms, the specification and drawings are to be regarded in an illustrative rather than a restrictive sense in order to help understand the present invention. It is obvious to those skilled in the art that various modifications and changes can be made thereto without departing from the broader spirit and scope of the invention.