KR100535644B1 - Call drop rate reduction method in mobile communication system - Google Patents

Abstract

The present invention relates to a method for reducing call disconnection rate in a mobile communication system.

According to an aspect of the present invention, there is provided a method for reducing call truncation rates in a mobile communication system providing a voice call and a high speed packet data call service. When it is reported that the high-speed packet data call that has occurred and is in service has been abnormally terminated, checking whether the base station has transmitted a paging signal to the mobile station or has received a response signal for the paging signal from the mobile station; And if the base station transmits a paging signal to the mobile station and receives a response signal for the paging signal, processing the high-speed packet data service in service as normally terminated. .

Accordingly, the present invention provides a high speed packet to a specific mobile station in a mobile communication system providing a voice call and a high speed packet data call service, such as a mobile communication system providing CDMA 2000 1x and 1x EV-DO services using the same base station. While providing a data service, when an incoming call connection request for a voice call occurs and it is reported that the high speed packet data call currently in service is abnormally terminated, the base station has transmitted a paging signal to the mobile station or not according to the paging signal. By checking whether a response signal has been received and processing the high-speed packet data service that was in service, the system terminates service switching by normal call termination generated between the BSC / PCF and each channel card of the base station. Recognize your call truncation rate statistics Since it is not reflected, it provides the system administrator with accurate information about the call processing result and its statistics.

Description

CALL DROP RATE REDUCTION METHOD IN MOBILE COMMUNICATION SYSTEM}

The present invention relates to a mobile communication system, and more particularly to a mobile communication system providing a voice call and a high-speed packet data call service, such as a mobile communication system providing CDMA 2000 1x and 1x EV-DO services using the same base station. While providing a high speed packet data service to a specific mobile station, when an incoming call connection request for a voice call is reported that the high speed packet data call currently in service is abnormally terminated, the base station transmits a paging signal to the mobile station. The present invention relates to a method for reducing call disconnection rate in a mobile communication system, which processes whether a fast packet data service in service is normally terminated by checking whether or not a response signal to the paging signal is received.

In general, a mobile communication system based on the Interim Standard (IS) -95 is a form of providing a voice-oriented service, but the recent International Mobile Telecommunication (IMT) -2000 service is a high-speed packet data service, a video service or a packetized service. Evolving into a system that supports multimedia services such as voice services.

In particular, the Code Division Multiple AZ Data Only (CDMA) service is a technology capable of high-speed packet data service having a data rate of up to about 2.4 Mbps on a forward link as well as existing IS-95-based voice call service and data service. to be.

In addition, the 1x EV-DO service can be implemented by newly building base station equipment while using the CDMA 2000 1x system as it is, which can service different channel cards, that is, existing IS-95-based voice calls and data in the same base station. Equipped with a CDMA 2000 1x channel card and a 1x EV-DO channel card capable of serving high-speed packet data for multimedia service support, and using a hybrid terminal capable of selectively receiving all of the above services. The CDMA 2000 1x and 1x EV-DO services can be implemented.

1 is a block diagram showing a network configuration of a mobile communication system providing a conventional CDMA 2000 1x and 1x EV-DO service. As shown therein, a mobile station 10 and a base station (BTS) 11 are shown. ), Control Station (BSC) / Packet Controller (PCF) (Base Station Controller / Packet Control Function) (12), Switcher (MSC) / Visitor Location Register (VLR) (13), A packet data serving node (PDSN) 14, a packet core network (PCN) 15, and an internet network 16 are provided.

The base station 11 and the BSC / PCF 12 connect a plurality of mobile stations 10 to the PDSN 14, and when the mobile station 10 requests a voice call or packet data call service to the base station 11 to which it is wirelessly connected. In case of a voice call, the BSC / PCF 12 transmits another external communication network (PSTN, PCS, PLMN) through the MSC / VLR 13, which is responsible for the overall management of the system such as subscriber information and billing information for each mobile station 10. And the like, and in the case of the packet data call service, determine the PDSN 14 serving as an interface of the packet data and connect the PCN 15 and the Internet network 16 through the determined PDSN 14. To be connected.

Here, the mobile station 10 is a hybrid terminal capable of receiving both CDMA 2000 1x service and 1x EV-DO service, and uses a channel card for CDMA 2000 1x installed therein according to the service type defined by the mobile communication service provider. In the case of receiving a service or using a high-speed packet data, a call connection is attempted using a 1x EV-DO channel card to receive the service.

That is, the mobile station 10 performs a CDMA 2000 1x call connection attempt and service start operation by tuning a CDMA 2000 1x channel frequency in case of a voice call attempt according to a service type, and in case of a fast packet data call attempt, 1x EV. -1x EV-DO call connection attempt and service start operation by tuning channel frequency allocated for DO.

Then, in the base station 11, different channel cards 11-1 and 11-2, that is, channel cards 11-1 for CDMA 2000 1x capable of servicing voice calls and data based on existing IS-95. ) And a 1x EV-DO channel card 11-2 capable of serving high-speed packet data, thereby implementing both CDMA 2000 1x and 1x EV-DO services. 1) and 1x EV-DO channel card 11-2 are used to allocate separate channel frequencies by separating FA (Frequency Assignment).

Meanwhile, in the mobile communication system providing both CDMA 2000 1x and 1x EV-DO services, the service switching process in the mobile station 10 will be described with reference to FIG. 2, and the mobile station 10 is in a 1x EV-DO service. Assuming that the mobile station 10 which is provided with the high speed packet data service using the 1x EV-DO channel frequency is received from the base station 11 at every defined slot cycle index period even if the mobile station 10 is receiving the service. It is monitored whether a CDMA 2000 1x paging signal is received (S20 and S21).

When the CDMA 2000 1x paging signal is not received as a result of the monitoring, the mobile station 10 terminates the 1x EV-DO service connection while continuing to receive the 1x EV-DO service and attempting to terminate the packet data service. Message to indicate that the channel card 11-2 for the 1x EV-DO of the base station 11 is transmitted.

Then, as shown in FIG. 4, the mobile station 10 releases the channel connection in the channel connected state in which the traffic channel is formed and transitions to the channel connection standby state in which no data is transmitted. Initializes the formed traffic channel and transitions to an initialization state for acquiring system information through a pilot channel, a data rate control (DRC) channel, and the like, and finally performs a series of procedures for terminating the service (S22). S24).

However, as a result of the monitoring, when the CDMA 2000 1x paging signal is received from the base station 11, the mobile station 10 turns a radio frequency (RF) signal tuned to the 1x EV-DO channel frequency currently being serviced. It is turned off (S25).

In addition, the mobile station 10 terminates the current 1x EV-DO service and simultaneously sends a message indicating that the radio frequency is re-tuned to the CDMA 2000 1x channel frequency of the 1x EV-DO channel card 11 of the corresponding base station 11. Without transmitting to -2), the CDMA 2000 1x channel card 11-1 and the CDMA 2000 1x voice call service of the base station 11 are started (S26, S27).

Here, the 1x EV-DO channel card 11-2 in the base station 11 serving high speed packet data with the mobile station 10 receives the CDMA 2000 1x paging signal and receives 1x EV-. In the process of turning off the radio frequency signal tuned to the DO channel frequency, the mobile station 10 does not receive a message indicating that the 1x EV-DO service is terminated. 10) The pilot signal and the DRC (Data Rate Control) signal, which were received from the uplink signal, are abnormally lost, and it is determined that abnormal 1x EV-DO call disconnection has occurred at the present time.

That is, as shown in FIG. 5, the mobile station 10 immediately initializes the formed traffic channel without shifting from the channel connected state in which the traffic channel is formed to the channel connection standby state (Idle State), and the pilot channel and the DRC channel. By transitioning to an Initialization State for acquiring system information through, for example, the 1x EV-DO channel card 11-2 in the base station 11 indicates that the mobile station 10 has abnormally terminated the service. Report to / PCF 12 (S22 to S24).

Meanwhile, referring to FIG. 3, a service switching process in a mobile communication system providing CDMA 2000 1x and 1x EV-DO services will be described with reference to FIG. 3. When a call connection request is received, it is determined whether the received new call connection request requires a CDMA 2000 1x service or a 1x EV-DO service (S30, S31).

As a result of the determination, if there is a new call request for the CDMA 2000 1x service, the mobile station 10 requesting the service is allocated a CDMA 2000 1x channel frequency, and the CDMA 2000 1x service is started (S32, S33).

Then, if a bad frame continues to occur during the service, the CDMA 2000 1x channel card 11-1 in the base station 11 terminates the CDMA 2000 1x call being served from the mobile station 10. Check whether the message is received (S34), if the message is received, the service is normally terminated according to a normal call termination procedure (S35), otherwise, the service is abnormally terminated and this is the BSC / PCF 12 Report to (S39).

On the other hand, if the received new call connection request is a 1x EV-DO service, the BSC / PCF 12 similarly allocates the 1x EV-DO channel frequency to the mobile station 10 and starts the 1x EV-DO service ( S36 and S37, and then check whether the message indicating that the 1x EV-DO call currently being serviced is received from the mobile station 10 ends the service normally (S38, S35), or abnormally terminates the service (S39). ).

Here, when the service for the CDMA 2000 1x call and 1x EV-DO call is abnormally terminated, the BSC / PCF 12 reports to the higher level managing call truncation rate statistics during the 1x EV-DO high speed packet data service. In the case of providing the CDMA 2000 1x call service, the BSC / PCF 12 transmits the base station 11 even though normal service switching occurs between itself and each channel card 11-1 and 11-2 of the base station 11. According to the report of the 1x EV-DO channel card 11-2 in FIG. 1, the call cut-off rate statistics on the system side reflect the abnormal call termination.

Accordingly, in the above conventional technology, in a mobile communication system in which CDMA 2000 1x and 1x EV-DO services are serviced using the same base station, the hybrid terminal provides a CDMA 2000 1x paging signal during 1x EV-DO high speed packet data service. When receiving, the terminal stops the 1x EV-DO service in service without transmitting a signal indicating that the terminal stops the 1x EV-DO service, and the system loses the backward signal from the hybrid terminal. By determining that the call that was being serviced is abnormally terminated, the system recognizes the service switching due to normal call termination occurring between the BSC / PCF and each channel card of the base station as abnormal call termination and reflects it in the call truncation rate statistics. In addition to providing inaccurate information to managers, Manpower and time wasted to work to identify the cause.

Accordingly, the present invention has been proposed to solve the above problems, and provides a voice call and a high-speed packet data call service like a mobile communication system providing CDMA 2000 1x and 1x EV-DO services using the same base station. In the mobile communication system, when the high speed packet data call that is currently being serviced is reported abnormally terminated due to an incoming call connection request for a voice call while providing a high speed packet data service to a specific mobile station, It is an object of the present invention to provide a method for checking whether a paging signal is transmitted to the mobile station or receiving a response signal for the paging signal so that a high speed packet data service in service is normally terminated.

According to an aspect of the present invention, there is provided a method for reducing call truncation rates in a mobile communication system that provides a voice call and a high speed packet data call service, while providing a high speed packet data call service to a mobile station. When a voice call related incoming call connection request is generated and it is reported that the high speed packet data call in service is abnormally terminated, the base station has transmitted a paging signal to the mobile station or receives a response signal for the paging signal from the mobile station. Checking whether or not; And, if the base station transmits a paging signal to the mobile station and receives a response signal for the paging signal, the base station processes the high-speed packet data service in service as being normally terminated.

Hereinafter, an embodiment according to the present invention will be described in detail with reference to the accompanying drawings.

1 is a block diagram showing a network configuration of a mobile communication system implementing a method for reducing call disconnection rate in a mobile communication system according to the present invention. As shown in FIG. 1, a mobile station 10 and a base station (BTS) are provided. (11), Control Station (BSC) / Packet Controller (PCF) (Base Station Controller / Packet Control Function) (12), Switcher (MSC) / Visitor Location Register (VLR) ( 13), a packet data serving node (PDSN) 14, a packet core network (PCN) 15, and an internet network 16. The configuration is the same as in the prior art.

However, when the CDMA 2000 1x channel card 11-1 of the base station 11 transmits a paging signal to the mobile station 10 to start the CDMA 2000 1x voice call service to the mobile station 10, the base station ( 11), when the CDMA 2000 1x channel card 11-1 receives a request from the BSC / PCF 12 to transmit the paging signal to the mobile station 10, a response signal to the paging signal from the mobile station 10 is received. Is determined whether or not is received and reporting the result to the BSC / PCF 12 is different.

The BSC / PCF 12 provides a voice call or a high-speed packet data call service requested by a mobile subscriber through its mobile station 10, and the 1x EV-DO channel card 11 of the base station 11 is provided. -2), when the call currently being serviced is abnormally terminated, the CDMA 2000 1x channel card 11-1 of the base station 11 to start the CDMA 2000 1x voice call service to the mobile station 10 is received. Requesting whether the paging signal has been transmitted to the mobile station 10, retrieving channel resources according to the result of the request, controlling the service to be terminated normally, and reporting the result to a higher level managing call disconnection rate statistics. .

The present invention can be implemented in a mobile communication system capable of simultaneously or selectively serving a voice call and a high-speed packet data call. The network configuration of the present invention provides a CDMA 2000 1x and a 1x EV-DO service in the same base station. It will be described on the assumption that the CDMA 2000 1x service and the 1x EV-DO service can be simultaneously or selectively serviced using.

In addition, it is assumed that the mobile station 10, which is a hybrid terminal capable of receiving both CDMA 2000 1x service and 1x EV-DO service, receives a CDMA 2000 1x paging signal while receiving 1x EV-DO high speed packet data service. Will be explained.

That is, through the mobile station 10, the mobile communication subscriber receives a voice call service using the CDMA 2000 1x channel card installed therein according to the service type defined by the mobile communication operator, or receives the 1x EV-DO channel card. A high speed packet data call service is used.

In addition, in the base station 11, different channel cards 11-1 and 11-2, that is, channel cards 11-1 for CDMA 2000 1x capable of serving existing IS-95 based voice calls and data. And a 1x EV-DO channel card 11-2 capable of serving a high-speed packet data call, thereby implementing both CDMA 2000 1x and 1x EV-DO services. The CDMA 2000 1x channel card 11-11 is implemented. 1) and 1x EV-DO channel card 11-2 are used to allocate separate channel frequencies by separating FA (Frequency Assignment).

Referring to the flowchart of FIG. 6, the operation of the present invention will be described in the mobile communication system serving a CDMA 2000 1x and 1x EV-DO service using the same base station 11. Upon receiving the new call connection request of step 10), the BSC / PCF 12 determines whether the received new call connection request requires the CDMA 2000 1x service or the 1x EV-DO service (S60 and S61).

As a result of the determination, if there is a new call request for the CDMA 2000 1x service, the mobile station 10 requesting the service is assigned a CDMA 2000 1x channel frequency and the CDMA 2000 1x channel card 11-1 in the base station 11 is assigned. The CDMA 2000 1x service is provided to the mobile station 10 through S71.

Meanwhile, according to the assumption of the present invention, when there is a new call request for 1x EV-DO service, the BSC / PCF 12 allocates 1x EV-DO channel frequency to the corresponding mobile station 10 and 1x in the base station 11. The 1x EV-DO high speed packet data service is provided to the mobile station 10 through the EV-DO channel card 11-2 (S62 and S63).

Then, while providing the 1x EV-DO high speed packet data service, the BSC / PCF 12 receives a reverse pilot signal or DRC (Data Rate Control) from the mobile station 10 receiving the 1x EV-DO high speed packet data service. ) Signal is received, the packet data received from the PDSN 14 via the PCN 15 or the Internet network 16 continues to serve the mobile station 10 (S64).

At this time, even if the mobile station 10 is provided with the high-speed packet data service using the 1x EV-DO channel frequency, the mobile station 10 receives the CDMA from the base station 11 at every defined slot cycle index period. 2000 1x paging signal is monitored. If the CDMA 2000 1x paging signal is received from the base station 11, the mobile station 10 is tuned to the currently serving 1x EV-DO channel frequency radio frequency Turn off (Radio Frequency, RF) signal.

In addition, the mobile station 10 terminates the current 1x EV-DO service and simultaneously sends a message indicating that the radio frequency is re-tuned to the CDMA 2000 1x channel frequency of the 1x EV-DO channel card 11 of the corresponding base station 11. It is prepared to start the CDMA 2000 1x voice call service through the channel card 11-1 for CDMA 2000 1x of the base station 11 without transmitting to -2).

Here, since the 1x EV-DO channel card 11-2 of the base station 11 has abnormally terminated the current service, the channel card 11-2 reports this to the BSC / PCF 12, and the BSC / PCF 12 Request confirmation of whether the mobile station 10 has transmitted a paging signal to the mobile station 10 by the CDMA 2000 1x channel card 11-1 of the base station 11 that intends to initiate a CDMA 2000 1x voice call service to the mobile station 10. (S66).

Then, if the CDMA 2000 1x channel card 11-1 of the base station 11 reports to the BSC / PCF 12 that a paging signal has been transmitted to the mobile station 10, the CDMA 2000 1x channel The BSC / PCF 12, which has reported that the paging signal is transmitted from the card 11-1 to the mobile station 10, checks again whether or not the mobile station 10 has received a response signal for the paging signal. (S67).

In response to the request of the BSC / PCF 12, the CDMA 2000 1x channel card 11-1 in the base station 11 transmits a paging signal to the corresponding mobile station 10 and then responds to the paging signal. Through a method of checking whether a signal is received within a predetermined time or the like, the mobile station 10 checks whether a response signal to the paging signal is received and reports the result to the BSC / PCF 12.

Then, when the BSC / PCF 12 receives a report from the CDMA 2000 1x channel card 11-1 in the base station 11 that it has received a response signal for the paging signal, the BSC / PCF 12 receives the 1x EV-DO service in service. The channel resource is recovered and the service is normally terminated (S69).

That is, the BSC / PCF 12 reports that the call is normally completed to the upper end of managing call truncation rate statistics.

However, if the BSC / PCF 12 does not receive a report that the response signal for the paging signal is received from the channel card 11-1 for CDMA 2000 1x in the base station 11, the CDMA 2000 of the base station 11 When the 1x channel card 11-1 controls to retransmit the paging signal to the mobile station 10 (S68), and receives a report that the response signal for the paging signal is received, the service is performed in the same manner as in the step S69. Exit normally

Here, the BSC / PCF 12 receives the response signal for the paging signal from the CDMA 2000 1x channel card 11-1 in the base station 11 by repeating the processes S66 to S68 for a predetermined number of times. Waits for a report, and if it does not receive a report indicating that it has received a response signal for the paging signal even during the predetermined number of times, it automatically recovers the channel resources and terminates the service normally. In this case, the 1x EV-DO service in service is normally Since the response signal to the paging signal for the CDMA 2000 1x call connection attempted to terminate but the new call connection is attempted is not received from the mobile station 10, the call connection fails for the voice call.

The predetermined number of times is adjustable according to the performance and environment of the system.

On the other hand, without receiving a call termination message indicating that the 1x EV-DO service currently being serviced is received from the mobile station 10, the BSC / PCF 12 performs the CDMA 2000 of the base station 11 as in step S66. If the 1x channel card 11-1 is reported not to transmit the paging signal to the mobile station 10, the call is abnormally terminated due to the influence of the mobile station 10 or the system environment. The 1x EV-DO service is arbitrarily disconnected in the maintenance and repair area of the system storing the processing result.

As described above, when service switching to the CDMA 2000 1x service occurs during the 1x EV-DO service, the channel card 11-2 for the 1x EV-DO in the base station 11 serving the high speed packet data with the mobile station 10 is performed. 1x EV- from the mobile station 10 in the process of receiving the CDMA 2000 1x paging signal and turning off the radio frequency signal tuned to the 1x EV-DO channel frequency. If the BSC / PCF 12 reports that the call is abnormally terminated because the message indicating that the DO service is stopped is not received, the BSC / PCF 12 transmits a paging signal to the mobile station 10 in the base station 11. It is determined whether the mobile station 10 normally terminates the call by checking whether the paging signal is transmitted from the CDMA 2000 1x channel card 11-1 or whether the paging signal has been received.

As described above, the present invention provides a mobile communication system that provides a voice call and a high speed packet data call service, such as a mobile communication system that provides CDMA 2000 1x and 1x EV-DO services using the same base station. If, while providing a fast packet data service to the mobile station, it is reported that an incoming call connection request for a voice call has occurred and an abnormally terminated high speed packet data call is currently being serviced, the base station has transmitted a paging signal to the mobile station; or By checking whether or not the response signal for the paging signal has been received and processing the high speed packet data service in service, the service is switched by normal call termination occurring between the BSC / PCF and each channel card of the base station. Recognizes as normal call termination It does not reflect the call truncation rate statistics, which provides the system administrator with accurate information about the call processing result and the statistics.

1 is a block diagram showing a network configuration of a mobile communication system providing conventional CDMA 2000 1x and 1x EV-DO services.

2 is a flowchart illustrating a service switching process in a mobile station which is a hybrid terminal in a mobile communication system providing conventional CDMA 2000 1x and 1x EV-DO services.

3 is a flowchart illustrating a switching process of each service in a conventional mobile communication system providing CDMA 2000 1x and 1x EV-DO services.

4 is a state diagram showing a state transition of a mobile station according to a normal 1x EV-DO call termination in a mobile communication system providing conventional CDMA 2000 1x and 1x EV-DO services.

FIG. 5 is a state diagram illustrating a state transition of a mobile station due to termination of an 1x EV-DO call generated by receiving a CDMA 2000 1x page signal in a mobile communication system providing conventional CDMA 2000 1x and 1x EV-DO services. FIG.

Figure 6 is a flow chart showing the operation of the call cutting rate reduction method in the mobile communication system of the present invention.

*** Description of the symbols for the main parts of the drawings ***

10: mobile station 11: base station

11-1: Channel card for CDMA 2000 1x 11-2: Channel card for 1x EV-DO

12: BSC / PCF 13: MSC / VLR

14: PDSN 15: PCN

16: Internet network

Claims (2)

A method for reducing call truncation rates in a mobile communication system providing a voice call and a high speed packet data call service, wherein a voice call related incoming call connection request is generated to the mobile station while providing a high speed packet data call service to the mobile station. When it is reported that the high speed packet data call being ended abnormally ends, checking whether the base station has transmitted a paging signal to the mobile station or has received a response signal for the paging signal from the mobile station; And when the base station transmits a paging signal to the mobile station and receives a response signal for the paging signal, processing the high-speed packet data service in service as being normally terminated. How to reduce call cut rates in a system. 2. The method of claim 1, further comprising: retransmitting a paging signal to the mobile station when the base station transmits a paging signal to the mobile station but does not receive a response signal for the paging signal; After retransmitting the paging signal, if a response signal for the paging signal is not received for a predetermined number of times, automatically recovering channel resources and processing the high-speed packet data service in service as being normally terminated. A method for reducing call truncation rates in a mobile communication system.