KR100546509B1 - Method and System for Preventing Call Drop by Restricting Overhead Message Updated in 1X System During 1xEV-DO Traffic State - Google Patents

Abstract

The present invention relates to a method and a system for preventing call disconnection by limiting a search time of a 1X system in a 1xEV-DO traffic state.

Supporting 1xEV-DO system and 1X system, and periodically during the traffic state with the 1xEV-DO system to switch to the 1X system to receive an overhead message, when receiving a preset required overhead message the 1xEV-DO system Hybrid terminal to return to; A base station transmitter for transmitting and receiving packet data and voice data with the hybrid terminal; A base station controller controlling the base station transmitter; A mobile communication switching center providing a communication connection path for a communication call from the hybrid terminal; And a packet data serving node connected to the base station controller to transmit and receive the packet data to and from the 1xEV-DO system, thereby limiting a search time of the 1x system in a 1xEV-DO traffic state to prevent call disconnection. do.

According to the present invention, the number of occurrences of call disconnection with the 1xEV-DO system due to the discovery of the 1x system of the hybrid terminal in the 1xEV-DO traffic state can be greatly reduced.

CDMA 2000 1X, Hybrid Terminals, CDMA 2000 1x 1xEV-DO, AN, Traffic Status

Description

Method and System for Preventing Call Drop by Restricting Overhead Message Updated in 1X System During 1xEV-DO Traffic State}

1 is a block diagram schematically illustrating a system for reducing call disconnection by limiting an overhead message updated by a hybrid terminal in a 1X system according to a preferred embodiment of the present invention;

2A and 2B illustrate a channel structure of a forward link transmitted from a 1xEV-DO transmitter to a hybrid terminal;

3 is a diagram illustrating a channel structure of a reverse link for transmitting data from a hybrid terminal to a 1xEV-DO system;

4 is a flowchart illustrating a process of reducing call connection release by limiting an overhead message to be updated by switching to a 1X system in a 1xEV-DO traffic state according to a preferred embodiment of the present invention.

<Description of Symbols for Main Parts of Drawings>

110: hybrid terminal (HAT) 120: base station transmitter

122: 1X Transmitter (BTS) 124: 1xEV-DO Transmitter (ANTS)

130: base station controller 132: 1X controller (BSC)

134: 1xEV-DO controller (ANC) 140: mobile communication switching center (MSC)

142: HLR 144: VLR

146: PSTN 150: PDSN

160: IP network

The present invention relates to a method and system for preventing call disconnection by limiting the number of overhead messages that a hybrid access terminal (HAT) switches to 1X system and updates in a 1xEV-DO traffic state. . More specifically, the hybrid terminal designates an overhead message in the 1X system that updates at a predetermined periodic interval in the traffic state of the 1xEV-DO system, and the hybrid terminal only specifies an overhead message of a limited kind or quantity predefined. The present invention relates to a method and system for solving the problem of being disconnected from a 1xEV-DO system by automatically returning to the 1xEV-DO system.

The mobile communication system has been developed through the first generation analog AMPS (Advanced Mobile Phone Systems) and the second generation cellular (PC) / Personal Communication Service (PCS). International Mobile Telecommunication-2000 (IMT-2000), which is a communication, has been developed and commercialized.

The IMT-2000 system for multimedia mobile communication service has defined the standard of the synchronous IMT-2000 system in 3GPP (3rd Generation Partnership Projects) 2, an international standardization organization. The method based on (High Data Rate) was named "1x EV (Evolution)" and confirmed as an international standard. The CDMA 2000 1x EV-D0 (Data Optimized) system is a system that transmits data only from the CDMA 2000 1X system.

Hereinafter, for convenience of description, the CDMA 2000 1X system will be abbreviated as "1X system" and the CDMA 2000 1xEV-DO system as "1xEV-DO system".

The 1X system provides a high speed data service with a transmission rate of up to 307.2 Kbps in a form of a mixture of a circuit network and a packet network. On the other hand, the 1xEV-D0 system provides a high-speed packet data service having a transmission rate of up to 2.4 Mbps for packet data only.

However, these 1xEV-DO systems are currently used interchangeably with existing 1X systems. That is, the 1xEV-DO system and the 1X system are mixed in hardware in one radio base station or base station controller, but operations are performed separately. In other words, the base station transmitter is provided with a channel card for the 1xEV-DO system and a channel card for the 1x system, respectively. In addition, the base station controller also includes a data processing board for processing packet data transmitted and received in the 1xEV-DO system and a data processing board for processing data transmitted and received in the 1X system.

On the other hand, when the high-speed data is transmitted from the mobile communication system such as a wireless base station or a base station controller to the mobile communication terminal is transmitted using the 1xEV-DO system, and in the case of voice or low-speed data is transmitted using the 1X system.

Thus, a hybrid terminal capable of accommodating all of the communication services provided in a mixed state of 1xEV-DO system and 1X system periodically monitors each system at regular time intervals. That is, in the standby state, the hybrid terminal periodically searches between the 1X system and the 1xEV-DO system, and periodically searches for the 1X system even in the traffic using the 1xEV-DO system.

In particular, in the traffic state of the 1xEV-DO system, the hybrid terminal responds to a call signal such as voice call connection signal or short data such as a short message that may be transmitted from the 1X system, and periodically registers its location with the 1X system. It connects to 1X system and updates system resource such as system message, access message.

However, in the current traffic state of the 1xEV-DO system, the hybrid terminal stays in the 1X system until it periodically connects to the 1X system and updates all necessary system resources.

On the other hand, the 1xEV-DO system performs a call drop if no signal is detected from the hybrid terminal in a traffic state for a predetermined time, for example, 5.12 seconds. This is to more efficiently manage system resources by releasing a call connection established with a hybrid terminal which is not searched for a certain time for any reason.

However, the current 1xEV-DO system has a structure in which the hybrid terminal that has lost the call connection cannot know at all why. In other words, whether the hybrid terminal, which was connected to the 1xEV-DO system, moved to the radio shadow area to release the call connection, whether the communication system failed and disconnected the call, switched to the 1X system, and released the call connection. There is a problem in that no information to be determined is provided.

In order to solve the above-described problem, the present invention provides an overhead message in a 1X system in which the hybrid terminal updates at predetermined periodic intervals in the traffic state of the 1xEV-DO system, and the hybrid terminal is a limited type or a predetermined type. It is an object of the present invention to provide a method and system for solving the problem of being disconnected from a 1xEV-DO system by automatically returning to a 1xEV-DO system when only a number of overhead messages are received.

To this end, the present invention is a system for preventing call disconnection that occurs during the traffic state of the hybrid terminal and the 1xEV-DO system, in conjunction with the 1X system 1X mode for receiving a voice signal transmission service or a low-speed data transmission service And operating in a 1xEV-DO mode for receiving a high-speed data transmission service in conjunction with the 1xEV-DO system, periodically switching to the 1X system during a traffic state with the 1xEV-DO system, and receiving an overhead message. A hybrid terminal performing a return process to the 1xEV-DO system upon receiving a preset required overhead message; A base station transmitter including a 1xEV-DO transmitter for transmitting and receiving packet data to and from the hybrid terminal and a 1x transmitter for transmitting and receiving voice and data to and from the hybrid terminal; A base station controller including a 1xEV-DO controller for controlling a transmission service of the packet data of the 1xEV-DO transmitter and a 1x controller for controlling a transmission service of the 1x transmitter; And a packet data serving node connected to the 1xEV-DO controller for transmitting and receiving the packet data to and from the 1xEV-DO system. Provide a system that reduces call disconnection.

According to another object of the present invention, a method for reducing call disconnection occurring during a traffic state between a hybrid terminal and a 1xEV-DO system, comprising: (a) the hybrid terminal sequentially initializing a 1x mode and a 1xEV-DO mode to a standby state; Maintaining; (b) the hybrid terminal performing dual monitoring on the 1x mode and the 1xEV-DO mode in the standby state; (c) the hybrid terminal entering a traffic state of the 1xEV-DO mode and establishing a connection and session to transmit and receive packet data; (d) switching to the 1X system when the hybrid terminal reaches a preset monitoring time; (e) the hybrid terminal switching to the 1X system and receiving an overhead message; And (f) returning to the 1xEV-DO traffic state of the 1xEV-DO traffic state when the hybrid terminal receives all preset overhead messages. It provides a method to reduce call disconnection by limiting the number.

According to still another object of the present invention, a hybrid terminal which checks an overhead message received in a transition state to a 1X system and returns to a 1xEV-DO system when a predetermined condition is satisfied, wherein the 1xEV-DO system and the 1X system are replaced. A timer for repeatedly measuring the monitoring time for dual monitoring; A searcher module for tracking and changing a frequency to perform a switching operation between the 1X system and the 1xEV-DO system in hardware and to receive the overhead message; A finger module for demodulating the overhead message received by the searcher module; And controlling the switching operation by software, and controlling data transmission / reception between the 1X system, the 1xEV-DO system, and the hybrid terminal, when a preset required overhead message is received in the switching state to the 1X system. It provides a hybrid terminal comprising an MSM chip for controlling to return to the 1xEV-DO system.

Hereinafter, exemplary embodiments of the present invention will be described in detail with reference to the accompanying drawings. First of all, in adding reference numerals to the components of each drawing, it should be noted that the same reference numerals are used as much as possible even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

1 is a simplified block diagram of a system 100 for reducing call disconnection by limiting overhead messages updated by a hybrid terminal 110 in a 1X system in accordance with a preferred embodiment of the present invention.

As shown in FIG. 1, the system 100 according to the present invention has a configuration in which a 1 × EV-DO system and a 1 × system are mixed. That is, a 1X system including a hybrid terminal 110, a 1X transmitter 122, a 1X controller 132, a mobile switching center (MSC) 140, and the like for the transmission of voice and data, data only. Hybrid terminal 110, 1xEV-DO (Access Network Transceiver) system (ANTS) 124, 1xEV-DO (Access Network Controller) (ANC) 134, packet data for transmission A 1xEV-DO system including a Packet Data Serving Node (PDSN) (hereinafter referred to as PDSN) 150 and an Internet Protocol (IP) network 160 has a mixed configuration.

The hybrid terminal 110 is provided with a voice service and a low speed data service through a 1X system, and has a hardware-separated configuration so that a high speed data service can be provided through a 1xEV-DO system. The hybrid terminal 110 is switched to the 1X mode to communicate through the 1X system in the standby state waiting for communication, and the 1xEV-DO system to the 1xEV-DO mode at regular intervals to check whether the data is received. It performs the operation of switching and returning to 1X mode again. That is, in the preferred embodiment of the present invention, the switching of the hybrid terminal 110 from the 1xEV-DO system to the 1X system of the traffic state is called 'switching', and the hybrid terminal 110 switched to the 1X system is the 1xEV-DO system. Switching to is called 'return'.

The switching and return function between the 1X system and the 1xEV-DO system is handled by software installed in a mobile station modem (MSM) chip, which is a kind of baseband modem embedded in the hybrid terminal 110, and the hardware Typically, this is done by tracking the frequencies used in each network by a component called a searcher connected to the MSM chip. That is, when the hybrid terminal 110 switches from the 1xEV-DO system to the 1X system, it is performed by tracking the frequency used by the searcher module in the 1X system under the control of the MSM chip, and returning from the 1X system to the 1xEV-DO system. This is done by tracking the frequencies used by the 1xEV-DO system.

When the hybrid terminal 110 receives the high speed data through the 1xEV-DO system in the 1xEV-DO mode, the hybrid terminal 110 transmits the data from the access network (AN) to the hybrid terminal 110 in consideration of a very large amount of data to be received. In the case of the forward link, the channels divided by the code division multiple access (CDMA) scheme transmit data through time slots divided into time division multiplexing (TDM), while hybrid In the case of the reverse link transmitted from the terminal 110 to the 1xEV-DO transmitter 124 and the 1xEV-DO controller 134, data is transmitted using the existing CDMA scheme as it is to accommodate a large number of subscribers. do.

In addition, while receiving the data in the traffic state of the 1xEV-DO mode, the hybrid terminal 110 periodically switches to the 1x mode to check whether there is an incoming call such as a voice call using the 1x system and then returns to the 1xEV-DO mode. The return operation is repeatedly performed. The hybrid terminal 110 switched to the 1X system performs an operation of receiving and updating an overhead message from the 1X system to perform voice call, location registration, and the like in the 1X system.

Here, the overhead message received and updated by the hybrid terminal 110 from the 1X system includes a system parameter message, an access parameter message, an extended system parameter message, and a neighbor list parameter ( Neighbor List Parameter messages, Channel List Parameter messages, and the like are included.

The system parameter message includes information such as a network ID (NID), a slot cycle index (SCI), and a packet zone ID (Packet Zone_ID), which are essential for call reception. The access parameter message contains the information required for the hybrid terminal 110 to access the 1X system from the 1xEV-DO system, and the extended system parameter message is added as the system evolves from the Interim Standard (IS) -95B system to the 1X system. System parameters are included. In addition, the neighbor list parameter message includes information on a cell ID of a neighbor cell adjacent to a cell where the hybrid terminal 110 is located, and the channel list parameter message includes a call by the hybrid terminal 110. Information is provided on a frequency channel capable of transmitting and receiving data or voice.

That is, the hybrid terminal 110 that has switched from the 1xEV-DO system to the 1X system stays in the 1X system until all of the overhead messages described above are updated. Meanwhile, if the hybrid terminal 110 does not respond to the pilot channel within a predetermined time, for example, 5.12 seconds, the 1xEV-DO system, which is in a traffic state with the hybrid terminal 110, releases the call connection formed with the hybrid terminal 110. .

Therefore, in the technical concept of the present invention, only the predetermined minimum overhead message necessary for the hybrid terminal 110 to respond to a call request from the 1X system so that the hybrid terminal 110 is not disconnected from the 1xEV-DO system. Upon receipt, it will return to the 1xEV-DO system even if it does not receive all of the remaining overhead messages. That is, information regarding the required overhead message required for returning to the 1xEV-DO system from the switch state to the 1X system is stored in the internal memory space of the hybrid terminal 110.

In more detail, the forced return from the 1X system to the 1xEV-DO system is performed by the MSM chip, the searcher module, and the finger module embedded in the hybrid terminal 110. The MSM chip is responsible for processing and controlling various operations generated in the hybrid terminal 110, and input / output between the hybrid terminal 110, the 1xEV-DO system, the 1X system, and a user who inputs a voice or key value. Control various data transmitted and received. The MSM chip includes a central processing unit (CPU) and a vocoder for voice coding.

Accordingly, when the hybrid terminal 110 is in a traffic state in the 1xEV-DO system, the MSM chip monitors the 1X system at regular time intervals using embedded software, which is implemented in hardware by the searcher module. . That is, the searcher module monitors the 1X system by tracking the frequency of the 1X system at predetermined time intervals under the control of the MSM chip.

Meanwhile, the overhead message received by the searcher module while monitoring the 1X system is delivered to the MSM chip, and the MSM chip delivers the overhead message received from the searcher module to the finger module. The finger module receiving the overhead message from the MSM chip demodulates the overhead message using a CMDA demodulation technique. Of course, the modulated signal or data received while monitoring the 1xEV-DO system is also demodulated using the TDMA demodulation technique.

Upon receiving the demodulated overhead message from the finger module, the MSM chip determines whether it receives a list of all required overhead messages stored therein. Here, the required overhead message list according to the preferred embodiment of the present invention includes a system parameter message and an access parameter message required to respond to a call in the 1X system among the various overhead messages described above. Of course, one or more overhead messages among the remaining overhead messages may be added to the required overhead message list according to a communication system or a communication environment.

On the other hand, if it is determined that the MSM chip has received all the preset overhead messages, the MSM chip returns to the 1xEV-DO system immediately from the 1X system regardless of whether the remaining overhead messages are received, thereby making a call between the hybrid terminal 110 and the 1xEV-DO system. Prevent disconnection.

Here, the overhead message that the hybrid terminal 110 receives and demodulates by switching to the 1X system is stored in an internal memory area or the like. Therefore, when the hybrid terminal 110 returns to the 1xEV-DO system and operates in a traffic state, and then switches back to the 1X system after a predetermined time, for example, 5.12 seconds has elapsed, the overhead message obtained in the previous step 1X system discovery task is returned. Can be used again That is, the hybrid terminal 110 may perform a call processing function in the 1X system when receiving only the remaining overhead messages except the required overhead message received in the previous step.

In the same manner as described above, the hybrid terminal 110, which has switched to the 1X system, limits the overhead message that must be updated to the required overhead message, thereby reducing the time to stay in the 1X system as much as possible, thereby reducing the hybrid terminal 110. And the likelihood of a call disconnection between the 1xEV-DO system and the 1xEV-DO system can be reduced.

The 1X transmitter 122 and the 1xEV-DO transmitter 124 are base station transceiver subsystems (BTSs) 120 that move voice and data to the hybrid terminal 110 through an air interface. Provide communication services. That is, voice or data is provided to the hybrid terminal 110 through the 1x transmitter 122 and only packet data is provided to the hybrid terminal 110 through the 1xEV-DO transmitter 124.

The 1X controller 132 and the 1xEV-DO controller 134 serve as base station controllers (BSCs) 130 to control the operation of the base station transmitter 120. That is, the 1X controller 132 for controlling the transmission of voice or data transfers the voice and / or data transmitted from the 1X transmitter 122 to the mobile switching center 130, and the 1xEV-DO controller 134 transmits 1xEV-. Data transmitted from the DO transmitter 124 is transmitted to the PDSN 150.

Mobile switching center 140 physically and signally connects multiple 1X controllers 132 to other mobile switching centers or Public Switched Telephone Networks (PSTNs) 146, from hybrid terminal 110. Provides by switching the communication connection path of the 1X system for the communication call.

In addition, the mobile communication switching center 140 has a home location register (HLR) 132, which is a database storing information of the hybrid terminal 110 registered therein, and within its own area. Call the subscriber by obtaining profile information of the hybrid terminal 110 from a visitor location register (VLR) 134 which is a database storing information of the hybrid terminal 110 Process. Here, the profile information includes a mobile identification number (MIN), an electric serial number (ESN) of the hybrid terminal 110, and information on subscribed additional services.

The 1xEV-DO system, which is a packet data transmission system for high-speed data transmission, is connected to the PDSN 150 based on TCP / IP, and transmits and receives various data with the IP network 160 in the form of an IP packet (Internet Protocol Packet). . After receiving the packet data transmitted from the IP network 160 to the hybrid terminal 110, the received packet data is loaded into the time slot divided by the TDM scheme and transmitted to the hybrid terminal 110. The CDMA data modulated by the CDMA method transmitted from the hybrid terminal 110 is received, packet data is generated using the received CDMA data, and the generated packet data is transmitted to the PDSN 150.

In the 1xEV-DO system, in the forward link, the wireless base station transmits the maximum power without using the power control, and provides only the hard handoff function. However, the reverse link performs power control for each terminal and supports not only hard handoff but also soft handoff.

2A and 2B illustrate a channel structure of a forward link transmitted from the 1xEV-DO transmitter to the hybrid terminal 110.

As shown in FIG. 2A, the forward link is composed of a pilot channel, a medium access control (MAC) channel, a control channel, and a traffic channel. The pilot channel is a channel through which the 1xEV-DO system transmits a pilot signal for tracking the hybrid terminal 110. The hybrid terminal 110 receives one or more pilot signals transmitted through the pilot channel, and among the received pilot signals. It connects to the wireless base station which transmitted the pilot signal having the greatest intensity. In addition, the pilot channel is also used by the hybrid terminal 110 for the reference for coherent detection of the radio base station of the 1xEV-DO system.

The MAC channel is mainly used for controlling the reverse link, and is composed of a reverse activity (RA) channel and a reverse power control (RPC) channel. Here, the RA channel is used to determine the transmission speed of the reverse link, and is also used to request the hybrid terminal 110 to lower the transmission speed when the channels of the reverse link become saturated. In addition, the RPC channel is a channel used by the hybrid terminal 110 to control transmission power in case of signal or data transmission on the reverse link.

The control channel is a channel used to transmit a broadcast message or a direct message for directly controlling a specific hybrid terminal 110 to the hybrid terminal 110 in the 1xEV-DO system. It is a channel used to transmit only pure packet data to the hybrid terminal 110 in the 1xEV-DO system.

Meanwhile, referring to FIG. 2B, the structure and data structure of the time slot of the forward link will be described. The forward link includes 16 time slots per frame, and one frame has a time of approximately 26.67 ms. With intervals. One timeslot consists of 2048 chips, first half slot 1024 chips and second half slot 1024 chips, with 1.67 ㎳ per time slot. Has

Both the first half slot or the second half slot contains Data Slot 400 Chips, MAC Slot 64 Chips, Pilot Slot 96 Chips, MAC Slot 64 Chips, and Data Slot 400 Chips. It is composed.

3 is a diagram illustrating a channel structure of a reverse link for transmitting data from a hybrid terminal 110 to a 1xEV-DO system.

The reverse link shown in FIG. 3 uses a code division multiple access scheme as in the 1X system, and is largely composed of an access channel and a traffic channel. The access channel consists of a pilot channel and a data channel, and the traffic channel consists of a pilot channel, a MAC channel, an acknowledgment channel, and a data channel. Here, the MAC channel is composed of a Reverse Rate Indicator (RRI) channel and a Data Rate Control (DRC) channel.

The access channel is used to transmit an Origination Signal (Connection_Request Message) and a Registration Signal (Route_Update Message). The access channel has a low transmission rate of 9.6 kbps for the stability of the wireless channel.

The pilot channel is used for the hybrid terminal 110 for reference for coherent detection of the radio base station of the 1xEV-DO system, similar to the pilot channel in the forward link described with reference to FIG. 2A. The data channel is a channel used to transmit data necessary for the hybrid terminal 110 to access the 1xEV-DO system.

The traffic channel is a channel used by the hybrid terminal 110 to transmit packet data to the 1xEV-DO system and supports various data transmission rates according to a wireless environment.

The pilot channel performs the same function as the pilot channel described in the access channel. The MAC channel is a channel used to control the data rate of the traffic channel and continues to be formed while the hybrid terminal 110 maintains a connection with the 1xEV-DO system. In the MAC channel, the RRI channel is used to inform the information of the data rate of the traffic channel transmitted by the hybrid terminal 110, and the value of the RRI is displayed on the hybrid terminal 110.

In addition, the DRC channel determines the demodulated data rate according to the channel environment of the current forward link and informs the base station. That is, the 1xEV-DO transmitter 124 transmits packet data to the hybrid terminal 110 by using the time slot of the forward channel. The criterion for determining the transmission rate of the packet data is the DRC Cover value transmitted by the hybrid terminal 110. to be. In order to determine the DRC Cover value, the hybrid terminal 110 measures a Carrier to Interference (C / I) value received from the 1xEV-DO transmitter 124 to determine a DCR Cover value capable of achieving a maximum transmission rate.

The response channel is a channel used by the hybrid terminal 110 to transmit a response signal for data received in a time slot unit in a forward direction. In order to reduce interference and to reduce interference, 1 of the basic timeslot path is used. Occupies only two.

The data channel is a channel used by the hybrid terminal 110 to transmit only packet data, similar to the data channel of the access channel.

Meanwhile, a packet, which is a basic transmission unit of a traffic channel, has a length of 26.66 ms and is transmitted by changing the transmission bit rate for each packet size. The pilot channel, traffic channel, DRC channel, and response channel used in the reverse link are distinguished using an orthogonal Walsh code.

4 is a flowchart illustrating a process of reducing call connection release by limiting an overhead message to be updated by switching to a 1X system in a 1xEV-DO traffic state according to a preferred embodiment of the present invention.

When the power is turned on by the user, the hybrid terminal 110 receives a pilot signal from the 1X controller 132 and the 1X transmitter 122 of the 1X system to initialize the 1X mode (Initialization) to maintain a standby state, and the 1X mode. After initializing the 1xEV-DO mode using the system parameter message acquired at the initialization and the pilot signals from the 1xEV-DO controller 134 and the 1xEV-DO transmitter 132, the standby state is maintained (S400).

The hybrid terminal 110 initializing the 1X mode and the 1xEV-DO mode performs dual monitoring between the 1X mode and the 1xEV-DO mode (S402).

Meanwhile, the hybrid terminal 110 transmits data from the 1xEV-DO transmitter 124 to the hybrid terminal 110 while the 1x system and the 1xEV-DO system are monitored in a standby state, or a user of the hybrid terminal 110 receives a key. When requesting data to the 1xEV-DO system through the operation, it is determined whether the device enters a traffic state for transmitting and receiving data by being activated in the 1xEV-DO mode (S404). In order to enter the traffic state, the hybrid terminal 110 needs to establish a connection with the 1xEV-DO transmitter 124 and a connection with the 1xEV-DO transmitter 124.

If the hybrid terminal 110 enters the traffic state of the 1xEV-DO mode in step S404, the hybrid terminal 110 transmits and receives packet data with the 1xEV-DO system (S406).

Meanwhile, in the traffic state of step S406, the hybrid terminal 110 transmitting and receiving packet data with the 1xEV-DO system may reach a preset monitoring time, for example, 5.12 seconds using a built-in timer to periodically search for the 1X system. Check (S408).

If it is determined in step S408 that the hybrid terminal 110 has reached the preset monitoring time (S410). Switching to the 1X system of the hybrid terminal 110 is performed by the operation of the embedded MSM chip and the searcher module. The hybrid terminal 110 receives and demodulates an overhead message by searching for the 1X system so as to switch to the 1X system and simultaneously respond to a call in the 1X system.

In step S410, the MSM chip of the hybrid terminal 110 that receives the overhead message continuously checks whether all preset overhead messages are received (S412).

If it is determined in step S412 that all of the required overhead messages have been received, the hybrid terminal 110 stops receiving other overhead messages in the 1X system and returns to the 1xEV-DO system (S414). Of course, the hybrid terminal 110 that transmits and receives packet data by returning to the 1xEV-DO system proceeds to step S410 again after a preset monitoring time and continuously repeats the operations up to S414.

According to an embodiment of the present invention, the 1xEV may occur while the hybrid terminal 110 receives an overhead message for call response or location registration in the 1X system in a traffic state of transmitting and receiving data with the 1xEV-DO system. The problem of disconnecting a call with a -DO system can be solved without using any resources of a 1X system or a 1xEV-DO system.

The above description is merely illustrative of the technical idea of the present invention, and those skilled in the art to which the present invention pertains may make various modifications and changes without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention but to describe the present invention, and the scope of the technical idea of the present invention is not limited by these embodiments. The protection scope of the present invention should be interpreted by the following claims, and all technical ideas within the equivalent scope should be interpreted as being included in the scope of the present invention.

As described above, in the related art, a problem arises in that a call connection is released for various reasons while a hybrid terminal in a traffic state in a 1xEV-DO system searches for a 1X system. However, according to the present invention, the overhead that a hybrid terminal needs to update in a 1X system is required. By limiting the number and type of messages, the hybrid terminal can return to the 1xEV-DO system as soon as possible, thereby solving the problem of unwanted call disconnection.

In addition, the method for disconnecting a call according to the present invention does not use any resources of the 1xEV-DO system or the 1X system, and the hybrid terminal checks whether it receives a preset overhead message by itself and returns to the 1xEV-DO system. The advantage is that it does not cause overload of communication system or waste of communication resources.

Claims (23)

During the traffic state between the hybrid terminal and the CDMA 2000 1xEV-DO (Evolution-Data Optimized) system (hereinafter referred to as '1xEV-DO system'), the CDMA 2000 1X system (hereinafter referred to as '1X system') will be periodically switched. A system for preventing a call disconnection with the 1xEV-DO system that occurs when, 1x mode for receiving a voice signal transmission service or a low speed data transmission service in conjunction with the 1X system and 1xEV-DO mode for receiving a high speed data transmission service in connection with the 1xEV-DO system. A hybrid terminal (HAT) performing a return process to the 1xEV-DO system when receiving an overhead message by periodically switching to the 1X system during a traffic state with the system and receiving a preset required overhead message. Hybrid Access Terminal); A base station transmitter including a 1xEV-DO transmitter for transmitting and receiving packet data to and from the hybrid terminal and a 1x transmitter for transmitting and receiving voice and data to and from the hybrid terminal; A base station controller including a 1xEV-DO controller for controlling a transmission service of the packet data of the 1xEV-DO transmitter and a 1x controller for controlling a transmission service of the 1x transmitter; And A Packet Data Serving Node (PDSN) connected to the 1xEV-DO controller for transmitting and receiving the packet data with the 1xEV-DO system. Hybrid mobile communication system to prevent the call disconnection by limiting the overhead message to be updated by switching to the 1X system of the 1xEV-DO traffic conditions comprising a. The method of claim 1, The overhead message is a system parameter message, an access parameter message, an extended system parameter message, a neighbor list parameter message, and a channel list parameter message. A hybrid mobile communication system that restricts head messages to prevent call disconnection. The method according to claim 1 or 2, The essential overhead message includes the system parameter message and the access parameter message. Hybrid mobile communication for preventing call disconnection by limiting an overhead message for updating by switching to 1X system among 1xEV-DO traffic conditions system. The method of claim 3, wherein When the hybrid terminal receives all the required overhead messages, the hybrid terminal stops receiving the overhead message and returns to the 1xEV-DO system. A hybrid mobile communication system that restricts a message to prevent call disconnection. The method of claim 1, The hybrid terminal is set to the 1X mode to communicate with the 1X system in an idle state, and the 1xEV-DO system at regular time intervals to check whether data is received from the 1xEV-DO system. And switching to the 1X system, and performing the operation of returning to the 1X system. The method of claim 1, When the hybrid terminal is receiving high-speed data from the 1xEV-DO system in the 1xEV-DO mode, the hybrid terminal switches to the 1x system at regular intervals to check whether there is a signal reception from the 1x system and then the 1xEV. -Hybrid mobile communication system for preventing call disconnection by limiting an overhead message for switching and updating to 1X system among 1xEV-DO traffic conditions, characterized by repeatedly performing an operation of returning to a DO system. The method of claim 1, In a forward link for transmitting data from the 1xEV-DO system to the hybrid terminal, a time division multiple access (TDMA) scheme is used, and data is transmitted from the hybrid terminal to the 1xEV-DO system. In reverse link transmission, the code division multiple access (CDMA) method is used to limit the overhead message of switching to 1X system in the 1xEV-DO traffic state. Hybrid mobile communication system to prevent disconnection. The method of claim 7, wherein In the forward link, power control is performed without performing power control and hard handoff is performed. In the reverse link, power control is performed for each of the hybrid terminals. A hybrid mobile communication system for preventing call disconnection by limiting an overhead message for switching and updating to a 1X system in a 1xEV-DO traffic state characterized in that a soft handoff is performed. The method of claim 1, The switching of the hybrid terminal to the 1X system is characterized in that the searcher module tracks and converts a frequency used by the searcher module in the 1X system by controlling a mobile station modem (MSM) chip embedded in the hybrid terminal. A hybrid mobile communication system for preventing call disconnection by limiting an overhead message for updating by switching to 1X system among 1xEV-DO traffic conditions. The method of claim 7, wherein in the forward link, A pilot channel through which the 1xEV-DO system transmits a pilot signal for tracking the hybrid terminal; A Medium Access Control (MAC) channel used for control of the reverse link; A control channel used to transmit a broadcast message or a direct message for directly controlling a specific hybrid terminal from the 1xEV-DO system to the hybrid terminal; And A traffic channel used to transmit only packet data from the 1xEV-DO system to the hybrid terminal. Hybrid mobile communication system to prevent the call disconnection by limiting the overhead message to update by switching to the 1X system of the 1xEV-DO traffic conditions, characterized in that using. A method for preventing a call disconnection with the 1xEV-DO system, which occurs when a switch between the hybrid terminal and the 1xEV-DO system is performed periodically to the 1X system. (a) the hybrid terminal sequentially initializing 1x mode and 1xEV-DO mode to maintain a standby state; (b) the hybrid terminal performing dual monitoring on the 1x mode and the 1xEV-DO mode in the standby state; (c) the hybrid terminal entering a traffic state of the 1xEV-DO mode and establishing a connection with a connection to transmit and receive packet data; (d) switching to the 1X system when the hybrid terminal reaches a preset monitoring time; (e) the hybrid terminal switching to the 1X system and receiving an overhead message; And (f) returning to the 1xEV-DO system when the hybrid terminal receives all preset overhead messages; Method for preventing the call connection release by limiting the overhead message to switch to update to the 1X system of the 1xEV-DO traffic state comprising a. 12. The method according to claim 11, wherein in step (a) The hybrid terminal releases the call connection by limiting an overhead message for switching to 1X system and updating the 1xEV-DO traffic state using the system parameter acquired when the 1X mode is initialized. How to prevent. 12. The process according to claim 11, wherein in step (d) The monitoring time is a time elapsed 5.12 seconds since the switch to the 1xEV-DO system, characterized in that to limit the search time of the 1x system of the 1xEV-DO traffic conditions to prevent call disconnection. 12. The process according to claim 11, wherein in step (d) The conversion is performed by the hardware operation of the searcher module that tracks the frequency used in the 1X system under the control of the MSM chip embedded in the hybrid terminal. A method of preventing call disconnection by limiting overhead message updates. 12. The process according to claim 11, wherein in step (e) The hybrid terminal demodulates the received overhead message and stores the demodulated message in a predetermined memory space, thereby limiting an overhead message for updating by switching to a 1X system in a 1xEV-DO traffic state. . 12. The method according to claim 11, wherein in step (f) The mandatory overhead message includes a system parameter message and an access parameter message. The method of claim 1, wherein an overhead message for switching and updating to a 1X system in a 1xEV-DO traffic state is limited. 12. The method according to claim 11, wherein in step (f) The return is performed by a hardware operation of a searcher module that tracks a frequency used in the 1xEV-DO system under the control of an MSM chip embedded in the hybrid terminal. A method of preventing call disconnection by limiting overhead messages that are switched and updated. The method of claim 11, The hybrid terminal converts and updates the 1X system in the 1xEV-DO traffic state, wherein the required overhead message received and stored in the previous search of the 1X system is used for the next search of the 1X system. Limiting an overhead message to prevent call disconnection. As a hybrid terminal that checks the overhead message received in the transition state to the 1X system and returns to the 1xEV-DO system when certain conditions are satisfied, A timer for repeatedly measuring a monitoring time for dual monitoring of the 1xEV-DO system and the 1X system; A searcher module for tracking and changing a frequency to perform a switching operation between the 1X system and the 1xEV-DO system in hardware and to receive the overhead message; A finger module for demodulating the overhead message received by the searcher module; And Control the switching operation by software, and control the data transmission and reception between the 1X system, the 1xEV-DO system and the hybrid terminal, if the preset required overhead message is received in the transition state to the 1X system the 1xEV Mobile Station Modem (MSM) chip to control return to DO system Hybrid terminal comprising a. The method of claim 19, The hybrid terminal operates by searching for a frequency used in the 1X system or a frequency used in the 1xEV-DO system at a preset monitoring period and switching to the 1X mode or 1xEV-DO mode. The method of claim 19, And the hybrid terminal demodulates the received required overhead message and stores the demodulated overhead message in a predetermined memory space. The method of claim 19, And the hybrid terminal uses the required overhead message received and stored in a previous search of the 1X system in a next search of the 1X system. The method of claim 19, The hybrid terminal storing the required overhead message, when receiving the remaining overhead message, the hybrid terminal, characterized in that to switch to a state capable of responding to the voice call from the 1X system or registration of the location to the 1X system terminal.

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