KR101488883B1 - Method and apparatus of processing CSFB service for improving call success rate - Google Patents

Abstract

The present invention relates to a method of processing a Circuit Switch Fall Back (CSFB) service in a 4G Evolved Packet System (EPS) defined by 3GPP.
According to the present invention, there is provided a CSFB (Circuit Switch Fall Back) service processing method for separately providing a circuit switching network service in an LTE network environment, the method comprising the steps of: (a) And performing paging; (b) upon receiving the CSFB service request message at the switching node, terminating the request paging timer; And (c) initiating a paging response timer for waiting for a paging response message from the MS in response to the CSFB service process, and performing paging, / RTI >

Description

TECHNICAL FIELD The present invention relates to a method and apparatus for processing CSFB service for improving call success rate,

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an advanced mobile communication network, and more particularly, to a method of processing a Circuit Switch Fall Back (CSFB) service in a 4G Evolved Packet System defined by 3GPP.

The 3GPP next generation core network (EPS) is an all-IP based system supporting various access networks including Long Term Evolution (LTE), High-Speed Packet Access (HSPA) / HSPA + as well as non-3GPP networks.

CS Fallback in the 3GPP EPS system means that a user equipment (UE) under service in a cell area of an LTE Evolved Terrestrial Radio Access Network (LTE E-UTRAN) uses network resources in a Circuit Switched (CS) (SMS), Location Services (LCS), and USSD (Unstructured Supplementary Service Data), as well as voice services, using a mobile switching center or an MSC server.

The CSFB function is used when the CS service can not be provided through the EPS network. For reference, EPS is an AIPN (All IP Network) type network, and it is necessary to link with IMS network to provide services such as voice and SMS. Therefore, when the IPS network does not support the IMS service or the IMS function can not be used, the CSFB function is used. The CSFB function must be supported by the UE as well as the network.

In relation to the CSFB function, Korean Patent Laid-Open Publication No. 2012-0013114 discloses a configuration in which 3G and LTE services can be used without any difference in the method of acquiring an LTE network according to the CSFB scheme in a mixed heterogeneous network with LTE. .

In the process of network evolution to LTE, CSFB technology using LTE and voice was introduced to the initial LTE commercialization service providers by standardizing CSFB technology using the existing 3G network, in a transitional form to data-based voice service (IMS, mVoIP).

However, since the construction range of LTE and 3G is different and heterogeneous transit occurs necessarily when voice service is provided, a single mode terminal can not simultaneously use data service in LTE network and voice service in 3G network . In addition, there is a problem that the reception call success rate may be lowered depending on the radio wave quality in the LTE of the terminal and the current state of the radio wave quality in the 3G.

SUMMARY OF THE INVENTION The present invention has been devised to solve the above problems and it is an object of the present invention to provide a CSFB service processing method capable of improving a call success rate by improving a call- And the like.

Other objects and advantages of the present invention will be described hereinafter and will be understood by the embodiments of the present invention. Further, objects and advantages of the present invention can be realized by the means and the combination shown in the appended claims.

In order to achieve the above object, a CSFB service processing method for improving a call success rate according to the present invention is a CSFB (Circuit Switch Fall Back) service processing method for separately providing a circuit switching network service in an LTE network environment, ) Initiating a request paging timer at the switching node of the communication system, the paging timer waiting for receiving a CSFB service request message; (b) upon receiving the CSFB service request message at the switching node, terminating the request paging timer; And (c) initiating a paging response with a response paging timer waiting for receipt of a paging response message from the terminal according to the CSFB service process.

According to another aspect of the present invention, there is provided a CSFB (Circuit Switch Fall Back) service processing apparatus for separately providing a circuit switching network service in an LTE network environment, the apparatus comprising: a paging processing module for performing paging processing to a node of a core network or a mobile communication terminal; A message receiving module for receiving a CSFB service request message and a paging response message at a mobile node in another node; And a response paging timer that waits for reception of a paging response message from the terminal, and performs paging with a request paging timer started, and receives a CSFB service request message And a paging timer control module for terminating the request paging timer, initiating a response paging timer, and performing paging. The CSFB service processing apparatus includes:

According to still another aspect of the present invention, there is provided a recording medium on which a program for performing Circuit Switch Fall Back (CSFB) service processing for providing a circuit switching network service in an LTE network environment is recorded, The method comprising: initiating a request paging timer that waits for a request message to be received and performing paging; terminating the request paging timer upon receipt of a CSFB service request message at an exchange node; A paging procedure for initiating a response paging timer to wait for reception of a paging response message from the terminal according to a process and a paging procedure and an exchange node receiving a paging response message from the terminal and executing a procedure for completing the CSFB service processing There is provided a computer-readable recording medium storing a program.

According to the present invention, when the paging timer for receiving the CSFB service request message from another switching node and the paging timer for receiving the paging response message from the terminal are separated and operated in the switching node, The paging timer expires before the paging response message is received from the terminal, and the call failure rate is improved to improve the call success rate.

BRIEF DESCRIPTION OF THE DRAWINGS The accompanying drawings, which are incorporated in and constitute a part of the specification, illustrate preferred embodiments of the invention and, together with the description of the invention below, And should not be construed as limiting.
1 is a schematic diagram illustrating a network configuration of a communication system in which the present invention is implemented.
2 is a block diagram of a CSFB service processing apparatus for improving a call success rate according to an embodiment of the present invention.
3 is a diagram illustrating a procedure of a CSFB service processing method for improving a call success rate according to an embodiment of the present invention.
4 is a diagram showing an example of a message reception process in accordance with the CSFB process of a voice incoming call in a mode in which an existing timer is operated.
5 is a diagram illustrating an example of message reception processing according to a CSFB service processing method according to an embodiment of the present invention.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings. Prior to this, terms and words used in the present specification and claims should not be construed as limited to ordinary or dictionary terms, and the inventor should appropriately interpret the concepts of the terms appropriately It should be interpreted in accordance with the meaning and concept consistent with the technical idea of the present invention based on the principle that it can be defined. Therefore, the embodiments described in this specification and the configurations shown in the drawings are merely the most preferred embodiments of the present invention and do not represent all the technical ideas of the present invention. Therefore, It is to be understood that equivalents and modifications are possible.

1 is a schematic diagram illustrating a network configuration of a communication system in which the present invention is implemented.

Referring to FIG. 1, the communication system in which the present invention is implemented is a mixed network of an LTE network and a 3G network. The mobile communication terminal 30 is a single mode terminal connectable to both the LTE network and the 3G network. The terminal 30 supports the CSFB function.

The 3G network includes an MSC 10, a radio network controller (RNC) 12, an SGSN 11, a base station (Node B) 13, and the like. The LTE network includes an MME 20, a Node B (eNode B) 21, and the like. The MME 20 and the MSC 10 communicate via the SGs interface protocol.

The mobile communication terminal 30 is a single mode terminal, that is, a terminal that can not connect to two kinds of communication networks at the same time but can connect to only one communication network. In addition, the mobile communication terminal 30 and the communication system provide and support a CSFB function. The CSFB function is a circuit switched fall back function. When a single-mode terminal accesses an LTE network and performs data communication or accesses an LTE network and a voice call or a 3G service call occurs, It is a processing function that changes the connection to the 3G network.

When a voice call is generated in the 3G network to the mobile communication terminal 30 connected to the LTE network, the MSC 10 of the 3G network transmits the MME 20 To perform paging notifying the voice incoming. The MME 20 transmits a CSFB service request message to the MSC 10 for CSFB processing because the corresponding terminal is a single mode terminal, and after transferring the control right to the 3G network according to the CSFB processing, . The mobile communication terminal 30 receives the paging to confirm the voice call, transmits the paging response message to the 3G network that has been CSFB, and performs the incoming process.

Accordingly, the MSC 10 must receive the CSFB service request message from the MME 20 together with the paging and receive the paging response message from the mobile communication terminal 30, thereby completing the normal CSFB receiving process . In addition, the MSC 10 starts paging with a timer, which sets the time to wait for acknowledgment in response to the paging process. If the response is not received until the timer expires, the call fails.

As described above, the present invention proposes a CSFB service processing method for reducing a call failure according to a timer at the time of paging performed with the CSFB processing in the MSC 10 and increasing a call success rate.

2 is a block diagram of a CSFB service processing apparatus for improving a call success rate according to an embodiment of the present invention.

2, the CSFB service processing apparatus 100 according to the present invention includes a paging processing module 110, a message receiving module 120, a paging timer control module 130, a CSFB processing module 140, and the like do.

Also, the CSFB service processing apparatus 100 according to the present invention may be included in the 3G network, included in the 3G network, or included in or included in the LTE network. In more detail, the CSFB service processing apparatus 100 according to the present invention is provided in the MSC 10 of the 3G network or in the MME 20 of the LTE network, and operates in call processing or CSFB service processing.

The paging processing module 110 performs a paging process for notifying an incoming call when an incoming call occurs. When the CSFB service is required, the paging processing module 110 performs paging with an exchange node (MSC or MME) of another network that requires CSFB processing, and performs paging with the mobile communication terminal 30 to be received.

The message receiving module 120 plays a role of receiving a response message according to the paging process in the paging processing module 110. That is, when performing paging with an exchange node of another network, the CSFB service request message is received or the paging response message according to paging is received by the mobile communication terminal 30.

Upon receiving a message from the message receiving module 120, the message transmission / reception between the exchange node (MME or MSC) of another network communicates a signal according to a protocol according to the SGs interface. On the other hand, the message transmission / reception between the exchange node (MME or MSC) of the core network and the mobile communication terminal 30 or the base station (Node B or e Node B) communicates a signal with a protocol according to the Iu interface.

The paging timer control module 130 controls the paging timer to be started together with the paging process. That is, the paging timer control module 130 may include a request paging timer Ts5 that waits for a CSFB service request message together with paging to an MME (or MSC) upon processing of a CSFB service according to the occurrence of an incoming call, And manages and controls the response paging timer Ts5 'waiting for receiving the paging response message for paging to the mobile communication terminal 30.

In detail, the paging timer control module 130 performs paging to the MME 20 according to the CSFB of the terminal 30 connected to the LTE network when an incoming call is generated in the 3G network, and at the same time, And waits for the reception of the CSFB service request message from the MME 20. After the paging, when the CSFB service request message is received in the MME 20, a response paging timer Ts5 ', which is another timer, is started to receive a paging response message from the mobile communication terminal 30 that has been CSFB processed from the LTE network to the 3G network . Upon receiving the paging response message from the mobile communication terminal 30, the incoming call processing is successfully completed.

In this way, the paging timer control module 130 divides and operates the timer in two ways, so that the call failure occurs due to the difference in the reception time of the CSFB service request message received from the exchange node and the paging response message received from the terminal 30 Can be solved.

The CSFB processing module 140 performs CSFB service processing according to the CSFB processing function and plays a role of successfully receiving an incoming call. That is, the CSFB service request signal is received from the switching node, the CSFB service process is performed, the paging response message is received from the terminal 30, and the incoming call is successfully received.

3 is a diagram illustrating a procedure of a CSFB service processing method for improving a call success rate according to an embodiment of the present invention.

Referring to FIG. 3, a CSFB service processing method according to the present invention will be described.

First, it is assumed that a voice call is generated in the 3G network to the terminal 30 connected to the LTE network. It is also assumed that the corresponding terminal 30 supports the CSFB function as a single mode terminal and the CSFB function as a communication system.

When an incoming call is generated in the 3G network, a request paging timer Ts5 is started to receive a CSFB service request message in order to perform a paging process for notifying an incoming call to the LTE network.

In addition, paging and timer control after reception of an incoming call in the 3G network is performed in the MSC 10, which is an exchange node of the 3G network.

A timer is started and a procedure for performing paging to the MME 20 of the LTE network is performed (S11)

The MSC 10 performs paging according to voice incoming, and thereafter, a procedure for monitoring whether a CSFB service request message is received from the MME 20 is performed (S12)

When the CSFB service request message is not received, it is checked whether the request paging timer Ts5 has expired, and if the CSFB service request message has not expired, the paging process is continuously performed. On the other hand, when the request paging timer Ts5 has expired, the call processing ends. (S13)

At the same time, the MME 20 of the LTE network receives the paging according to the voice call from the MSC 10, proceeds with the CSFB process, and transmits the CSFB service request message to the MSC 10 of the 3G network, The communication terminal 30 performs paging. At this time, as the CSFB service is processed, the mobile communication terminal 30 passes control from the LTE network to the 3G network.

Referring to the procedure of step S12, when the MSC 10 of the 3G network receives the CSFB service request message from the MME 20 of the LTE network, the request paging timer Ts5 for receiving the CSFB service request message is terminated , And starts a response paging timer Ts5 'for receiving a paging response message from the terminal (S20).

Thereafter, the MSC 10 of the 3G network continues paging with the start of the timer Ts5 '.

During the paging, the procedure proceeds to step S22 to check whether the paging response message has been received from the mobile communication terminal 30 that has undergone the CSFB processing. (S22)

If the paging response message is not received, it is checked whether the response paging timer Ts5 'has expired. If the response paging timer Ts5' has not expired, the paging process is continuously performed. If the response paging timer Ts5 ' (S23)

In addition, after the CSFB process is performed, the mobile communication terminal 30 of the LTE network transmits a paging response message in response to receiving the paging. Since the CSFB process is performed in the 3G network, ) To transmit the paging response message.

Returning to the procedure of step S22, when the paging response message is received from the mobile communication terminal 30 that has undergone the CSFB processing through the base station in the MSC 10 of the 3G network, the CSFB processing is completed, The process is completed successfully.

As described above, according to the present invention, at the time of CSFB service processing according to a voice incoming call, a request paging timer (Ts5) for awaiting reception of a CSFB service request message from an exchange node of another network, The response paging timer Ts5 'that waits for receipt of the paging response message according to the reception is distinguished and operated so as to improve the call success rate as compared with the conventional method of operating the timer.

FIG. 4 is a diagram illustrating an example of a message reception process according to the CSFB process of a voice incoming call performed in a conventional method of operating a timer. FIG. 5 is a flowchart illustrating a method of processing a CSFB service according to an exemplary embodiment of the present invention. And shows an example of reception processing.

Referring to FIG. 4, when paging is performed at the switching node, only one timer is started.

Here, a case is assumed in which a CSFB service request message is received at 9 seconds after the paging and a paging response message is received from the terminal at 11 seconds. In addition, one conventional timer has a period of 10 seconds as an example.

Referring to the drawing, paging is started at a time T1 (0 second), and one timer is started at the same time.

At time T2 (9 seconds), the CSFB service request message is received from the exchange node of another network. Thereafter, the timer expires at the time T3 (10 seconds), and the paging response message is received from the mobile communication terminal that has undergone the CSFB processing at the time T4 (11 seconds) after the expiration of the timer.

In this case, since the timer expires at the time T3, the paging response message is received from the terminal at the time point T4, which is a short time later. However, the incoming call can not be successfully processed and the incoming call fails due to the timer end.

In the CSFB commercial service, the time required for CSFB processing is estimated to be about 1.5 seconds. Therefore, if there is one existing timer, the call fails if the difference between T2 and T3 is within 1.5 seconds.

Next, referring to FIG. 5, when paging is performed at the switching node, the two divided timers are operated and controlled differently according to the embodiment of the present invention. That is, the request paging timer Ts5, which is the first timer, is started at the T1 time (0 second) at the same time as the paging.

As described above, when the CSFB service request message is received from the switching node at the T2 time point (9 seconds), the request paging timer Ts5 is terminated at this point and, at the same time, the response paging timer Ts5 ' Lt; / RTI >

Thereafter, the paging response message is received at the time T4 (11 seconds) from the CSFB-processed mobile communication terminal. Since the response paging timer Ts5 ', which is a new timer, is newly started at the time T2, the timer is not expired, Lt; RTI ID = 0.0 > paging < / RTI > response message.

In this case, even when the same situation is assumed, call reception fails due to the expiration of the timer in the past, but according to the embodiment of the present invention, the incoming call of the voice call normally succeeds due to the new timer, and the overall call success rate is improved .

That is, when the time required for CSFB processing, which is a general case of the CSFB commercial service described above, is 1.5 seconds, even when the difference between T2 and T3 is within 1.5 seconds, the call does not fail and a normal call is made. There is an effect of increasing.

The method of the present invention as described above may be embodied as a program and stored in a computer-readable recording medium (such as a CD-ROM, a RAM, a ROM, a floppy disk, a hard disk, or a magneto-optical disk).

While the specification contains many features, such features should not be construed as limiting the scope of the invention or the scope of the claims. In addition, the features described in the individual embodiments herein may be combined and implemented in a single embodiment. Conversely, various features described herein in a single embodiment may be implemented in various embodiments individually or in a suitable subcombination.

It is to be understood that, although the operations have been described in a particular order in the figures, it should be understood that such operations are performed in a particular order as shown, or that a series of sequential orders, or all described operations, . In some circumstances, multitasking and parallel processing may be advantageous. It should also be understood that the division of various system components in the above embodiments does not require such distinction in all embodiments. The above-described program components and systems can generally be implemented as a single software product or as a package in multiple software products.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. The present invention is not limited to the drawings.

110: Paging processing module 120: Message receiving module
130: Paging timer control module 140: CSFB processing module

Claims (11)

A Circuit Switch Fall Back (CSFB) service processing method for separately providing a circuit switching network service in an LTE network environment,
(a) When a voice call is made to the terminal, the Mobile Switching Center (MSC) of the 3G network performs paging for the terminal with the Mobile Management Entity (MME) of the LTE network, starts a request paging timer, Waiting for reception of a CSFB service request message to be transmitted;
(b) when the MSC receives the CSFB service request message before expiration of the request paging timer, ends the request paging timer and starts a response paging timer to wait for receiving a paging response message from the MS, If the CSFB service request message is not received until the expiration of the paging timer, processing the voice call termination failure processing; And
(c) if the paging response message is received before the expiration of the response paging timer, the MSC completes an incoming call for the voice call for the MS, and if the paging response message is not received until expiration of the response paging timer And processing the unsuccessful call reception of the voice incoming call. delete The method according to claim 1,
The step (c)
And a response paging timer is started at the same time when the request paging timer is terminated in the step (b). delete delete The method according to claim 1,
The step (a) and the step (b)
Wherein the CSFB service processing method is performed between the switching nodes of the core network through the SGs protocol. The method according to claim 1,
The step (c)
And the IU protocol between the switching node and the base station of the core network. A Circuit Switch Fall Back (CSFB) service processing apparatus for separately providing a circuit switching network service in an LTE network environment,
A paging processing module that performs paging processing to a node of the core network or the terminal when a voice call is made to the terminal;
A message receiving module for receiving a CSFB service request message from another node or receiving a paging response message from the terminal; And
A request paging timer for waiting for reception of the CSFB service request message and a response paging timer for awaiting reception of a paging response message transmitted by the terminal, and for initiating the request paging timer, And controls to perform paging when a CSFB service request message is received before the request paging timer expires by terminating the request paging timer, initiating a response paging timer, and performing paging before receiving the CSFB service request message. And a paging timer control module for processing a call termination failure of the voice incoming call when the request paging timer expires,
Wherein if the paging response message is received before the expiration of the response paging timer, the paging timer control module completes an incoming call for the voice call to the terminal when the paging response message is received, and if the paging response message is not received until expiration of the response paging timer, A CSFB service processing apparatus for improving the call success rate to process a call termination failure call. delete 9. The method of claim 8,
Wherein the paging timer control module comprises:
And a response paging timer is started at the same time when the request paging timer is terminated. CLAIMS 1. A recording medium on which a program for performing Circuit Switch Fall Back (CSFB) service processing separately providing a circuit switching network service in an LTE network environment is recorded,
When a voice call for the MS occurs, the Mobile Switching Center (MSC) of the 3G network performs paging for the MS with an MME (Mobile Management Entity) of the LTE network, starts a request paging timer, Waiting for reception of the service request message,
When the MSC receives the CSFB service request message before expiration of the request paging timer, waits for a paging response message from the MS to start a response paging timer after the request paging timer expires, If the CSFB service request message is not received,
The MSC terminates the voice incoming call to the MS when the paging response message is received before expiration of the response paging timer, and if the paging response message is not received until the response paging timer expires, A computer-readable recording medium recording a program for executing a procedure for processing an incoming call failure.

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