KR20030046855A - Service redirection method in a mobile communication system - Google Patents

Abstract

PURPOSE: A method for redirecting a service of a mobile communication system is provided to extensively use a service redirection message related to an NDSS(Network Directed System Section) in a CDMA 1x system. CONSTITUTION: A dual MS(Mobile Station)/AT(Access Terminal) receives a CDMA(Code Division Multiple Access) 1x system and selectively sends an origination message to a serving BS-1(Base Station)(100a). The serving BS sends a CM service request message to an MSC-1(Mobile Switching Center)(100b). The MSC-1 transmits a service redirection message to the serving BS to execute an NDSS operation(100c). The serving BS informs the dual MS/AT to originate packets to 1x EV-DO(Evolution Data Only) HRPD(High Rate Packet Data) system(100d). The dual MS/AT originates the packets(100e).

Description

How to switch service of mobile communication system {SERVICE REDIRECTION METHOD IN A MOBILE COMMUNICATION SYSTEM}

The present invention relates to a mobile communication system, and more particularly, to a method of providing a switching service to a terminal connected to two or more networks each supporting a different service.

Typical mobile communication systems, such as Code Division Multiple Access (CDMA), initially supported only voice services. However, as the communication technology is developed with the subscriber's demand, the mobile communication system is also being developed to support the data service. For example, initially mobile communication systems supporting voice services were analog systems and IS-95 A / B 2G systems. After the development of the IS-95 A / B 2G system, the CDMA2000 1x 3G system was introduced. Since then, 1x EV-DO (Evolution Data Only) HRPD system and 1x EV-DV (Data and Voice) system are introduced. There is a trend. In addition, the mobile terminal used by subscribers has also been developed from a mode supporting only one mode to supporting two modes. There is a so-called Dual Mode terminal. The trend of such mobile communication systems and terminals is to provide subscribers with data services as well as voice services.

On the other hand, the recently discussed technical consensus is that the base station system informs the terminal subscriber of outgoing redirection by using a service redirection message in the radio, when the subscriber makes an outgoing call between the exchange and the base station. In addition, there is a way to send and receive a signaling message using a Network Directed Service Selection (NDSS) message between systems to switch to another system.

FIG. 1 is a diagram illustrating a process in which an existing system switches a service between a system and a preferred system of an MS. The procedure is as follows.

In step 10a, the mobile station (MS) receives and examines a certain system, selects it, and uploads an origination message to the serving BS (BS).

In step 10b, the service base station BS-1 sends a CM Service Request message according to call origination to a mobile switching center (MSC-1). At this time, MSC-1 performs user registration and authentication according to standard methods. At this time, the exchange may determine that another system is more suitable for the MS according to the subscriber's preference information (eg, digital 2G rather than analog) registered in a system device such as a subscriber authentication center or a HLR (Home Location Register). If the current serving base station can provide the NDSS, the exchange may decide to switch the MS out to another system.

(Step 10c) The exchange MSC-1 transmits a service switch message for the serving base station BS-1 to perform NDSS operation.

(Step 10d) The serving base station BS-1 informs the MS of the switching information received from the exchange through a service switching message.

After receiving the service switch message, the MS finds the designated system and sends an origination message to the system.

In step 10f, the newly selected service base station BS-2 sends a CM Service Request message to the exchange MSC-2. MSC-2 performs user registration and authentication according to standard methods.

2 is a diagram illustrating a format of a service switch message used in an IS-95 2G system according to the prior art.

Referring to FIG. 2, the main information elements of a service redirection message (SRM) are as follows. The Protocol Discriminator is used to identify the purpose of the message currently in use. For example, the Protocol Discriminator indicates whether it is a mobility management message or a call processing message. Message Type is an identifier indicating the type of message currently being used. The IS-95 Redirection Record indicates to which system the IS-95 MS should switch and send. Mobile Identity (MIN / IMSI / TMSI / ESN) is the number currently used by MS and checks whether it is MIN number system, IMSI system or ESN system. The Cell Identifier List indicates the position of the cell where the current MS is located in the system. The slot cycle index is used to inform the base station of the slot paging index when the MS is operating in the slot paging mode. The signaling type is used to indicate whether the current system is Time Division Multiple Access (TDMA) or IS-95.

As you can see, there is some information that does not need to be used in the CDMA2000 1X environment. For example, CDMA2000 1X does not use TMSI, and does not consider interworking with GSM or TDMA networks in CDMA networks. Therefore, in order to provide service switching between the CDMA2000 1X system and the IS-95 A / B system, information for the CDMA2000 1X must be newly designed. If so, let's take a look at how the service switching message currently used in the wireless. Prior to the discussion, the messages defined in the wireless standard IS-2000-A related to service redirection include Service Redirection, Global Service Redirection, and Extended Global Service Redirection. There are three messages. The service switch message is a message used in 2G IS-95A. The global service switch message is a message used when the protocol version (MOB_PREV) of the terminal is 6 or less. The extended global service switch message is a message used when the protocol version of the terminal is 6 or more. Therefore, in the CDMA-2000 1X system, an extended global service switch message is mainly used. Since the information in the extended global service switch message includes the information of the existing service switch message (for 2G IS-95A) and the global service switch message (2G, IS-95B), the description of these is described in the extended global service switch message. We will only do this for messages.

FIG. 3 is a diagram illustrating a format of an extended global service redirection message used in the IS-2000-A wireless standard according to the prior art, and FIG. 4 is a detailed format of the REDIRECT_ALLOC field illustrated in FIG. 3. Figure showing. In FIG. 3, PILOT_PN is a value indicating a pilot PN sequence offset index of the base station. CONFIG_MSG_SEQ is a value indicating a configuration sequence message number. REDIRECT_ALLOC is a value indicating an overload class to which terminals to be switched currently belong, as shown in FIG. 4 to be described later. RETURN_IF_FAIL contains, when the redirection fails, which system to switch to, or return to the system to which the call was originally attempted, based on the criteria specified in RECORD_TYPE. 1 bit of information.

FIG. 5 is a diagram illustrating specific formats of the REDIRECT_TYPE and RECORD_TYPE fields illustrated in FIG. 3, and FIGS. 6A to 6C are diagrams illustrating fields according to examples of RECORD_TYPE values illustrated in FIG. 5. That is, FIG. 5 and FIGS. 6A to 6C show fields that are currently indicated by REDIRECT_TYPE value and RECORD_TYPE value whether or not service switching should proceed. Specifically, 1 bit of Redirect_P_REV_INCL indicates that the protocol revision value of the terminal to which the switch can be applied is designated as some value or the switch is applied to all terminals regardless of the protocol change value. One bit of Excl_P_REV_Ind indicates whether to switch (if 0) or to exclude (if 1) the switching for terminals having a protocol version within the range of [REDIRECT_P_MIN, REDIRECT_P_MAX]. The value of REDIRECT_P_MIN and REDIRECT_P_MAX represents 6 or more.

FIG. 7 is a diagram illustrating a format of a service switch message according to the prior art, and illustrates a format of a service switch message used in the IS-95A wireless standard. The information in this message is the information contained in the extended global service switch message shown in FIG. Therefore, further description thereof will be omitted.

Comparing FIG. 2 with FIG. 7 described above, it can be seen that service switching between the base station and the exchange is designed to support service switching of the wireless section. However, it can be easily seen that the extended global service switching message shown in FIG. 3 used by the CDMA2000 1X 3G terminal cannot be supported by the 2G service switching message shown in FIG. 2.

Accordingly, an object of the present invention is to provide a method for extending a service switching message related to NDSS used in an IS-95 A / B system in a CDMA2000 1X 3G system.

It is another object of the present invention to maximize the use of resources in the network and to make the subscriber more stable by defining additional messages and procedures in the existing wireless service switching procedure so that the service can be switched from the CDMA2000 1X system to the 1X EV-DO HRPD system. To provide a better service.

According to a first aspect of the present invention for achieving these objects, in a mobile communication system including a mobile terminal, a first base station supporting voice service, and a second base station supporting voice service and data service simultaneously, A method for switching the voice service of the mobile terminal when the terminal is in a common area that can receive services from the first base station and the second base station is proposed. The method includes determining whether call congestion occurs in the second base station when there is voice transmission from the terminal to the second base station, and voice from the terminal when it is determined that call congestion occurs in the second base station. Converting an origination to the first base station.

According to a second aspect of the present invention, in a mobile communication system including a mobile terminal, a first base station supporting voice service, and a second base station supporting voice service and data service simultaneously, the terminal includes the first base station. And a method of switching data services of the mobile terminal when it is in a common area that can receive service from the second base station. The method may further include determining whether there is a packet transmission for data service from the terminal to the first base station, and when the packet transmission is determined at the first base station, the first base station may transmit the voice transmission from the terminal. Switching to the second base station.

The foregoing has outlined rather broadly the features and technical advantages of the present invention in order that those skilled in the art may better understand the detailed description of the invention that follows.

Additional features and advantages of the invention will be described hereinafter which form the subject of the claims of the invention. Those skilled in the art should recognize that the disclosed concepts and specific embodiments of the invention may be readily used as a basis for modifying or designing other structures for achieving the same purposes of the present invention. Those skilled in the art should also recognize that structures equivalent to the invention do not depart from the spirit and scope of the broadest form of the invention.

1 is a view showing an operation of switching a service to a network preferred by a terminal in a mobile communication system according to the prior art.

2 is a diagram illustrating a format of a service switch message used in an IS-95 2G system according to the prior art.

3 is a diagram illustrating a format of an extended global service redirection message used in the IS-2000-A wireless standard according to the prior art.

4 is a diagram illustrating a specific format of the REDIRECT_ALLOC field shown in FIG. 3.

FIG. 5 is a diagram illustrating a specific format of the REDIRECT_TYPE and RECORD_TYPE fields shown in FIG. 3. FIG.

6A-6C show a field according to examples of RECORD_TYPE values shown in FIG. 5;

7 illustrates a format of a service switch message according to the prior art.

8 illustrates a format of a service switch message to be used in a CDMA2000 1x system according to an embodiment of the present invention.

FIG. 9 illustrates a specific format of the IS-2000 Redirection Record information element shown in FIG. 8; FIG.

FIG. 10 illustrates a specific format of the Service Redirection Info information element shown in FIG. 8; FIG.

11 is a diagram illustrating a RECORD_TYPE field of an extended global service switch message according to an embodiment of the present invention.

FIG. 12 is a view showing specifically an extended field according to an embodiment of the present invention among RECORD_TYPE values of the extended global service switch message shown in FIG. 11; FIG.

FIG. 13 is a diagram illustrating an NDSS providing process between a CDMA2000 1X system and a 1x EV-DO HRPD system according to an embodiment of the present invention. FIG.

DETAILED DESCRIPTION A detailed description of preferred embodiments of the present invention will now be described with reference to the accompanying drawings. It should be noted that reference numerals and like elements among the drawings are denoted by the same reference numerals and symbols as much as possible even though they are shown in different drawings. In the following description of the present invention, if it is determined that a detailed description of a related known function or configuration may unnecessarily obscure the subject matter of the present invention, the detailed description thereof will be omitted.

The present invention, which will be described below, is a signal procedure and message specification in a base station system for service switching between a CDMA2000 1X 3G system and an IS-95 A / B 2G system, and a wireless 1x EV-DO HRPD system, which has not existed previously, The purpose is to provide a service transition between 1x EV-DV systems that are expected to be commercially available. Prior to describing the present invention, the inventors of the present application will recognize that the following facts are recognized.

If IS-95 A / B's 2G system and CDMA2000 1X 3G system are commercially available at the same time, the 2G and 3G systems will each accommodate subscribers in a common geographic area. 2G subscribers cannot access 3G systems, but 3G systems can typically connect both 2G and 3G systems. When a subscriber of a dual mode terminal capable of receiving both 2G service and 3G service sends a packet service request to the 2G system, it is natural to switch to sending a packet to an adjacent 3G system. On the contrary, if a subscriber who has made a voice call to the 3G system cannot be accommodated in the 3G system due to the congestion of the network, the subscriber should be able to switch to the 2G system to make a voice call to the 2G system. An object of the present invention is to use a service redirection message that is used in a conventional radio, and network switching service between an analog system and a 2G system using NDSS (Network Directed Service Selection) during the exchange with the base station. In addition to extending the system and the 3G system, the present invention proposes a method for converting the packet transmission through the CDMA2000 1X 3G system to the 1x EV-DO system. The present invention facilitates voice service and packet service switching between IS-95 A / B 2G system, CDMA2000 1X 3G system, 1x EV-DO HRPD system, and 1x EV-DV system, which is expected to be commercialized in the future.

First, the signaling procedure and message specification in a base station system for service switching between a CDMA2000 1X 3G system and an IS-95 A / B 2G system will be described.

8 illustrates a format of a service switch message to be used in a CDMA2000 1x system according to an embodiment of the present invention. The service switch message according to the embodiment of the present invention contains contents defining fields of the service switch message that are not defined in the existing 3G IOS standard.

Referring to FIG. 8, the service switching message includes a protocol discriminator, a reserved-octet, a message type, an IS-2000 redirection record, a service redirection info, a mobile identity (IMSI), a mobile identity (esn), a cell identifier list, and a slot cycle index. It consists of the fields of. The service switch message consisting of these fields is a message sent from the exchange (MSC) to the base station.

Compared to the service switch message used in the IS-95 2G system as shown in FIG. 2, the terminal identifier corresponding to the TMSI / MIN is deleted from the service switch message according to the embodiment of the present invention. This is because, basically, the 3G IOS standard only considers the mobile communication system transitioning from a 3G system to a 2G system. That is, in the 3G system, only IMSI and ESN are considered as a mobile identity. In addition, information on mobile addressing and signaling type used only in an analog system or a 2G system is also deleted.

As the newly required information according to the principles of the present invention, an information element of the IS-2000 Redirection Record is introduced instead of the IS-95 Redirection Record shown in FIG. In this case, the IS-2000 switch record is formatted into the same field as the record type defined in the extended global service switch message of the wireless section as shown in FIG. 3. This field is used by the exchange to authenticate the user or to create a record based on its own information. In addition, a new element of service redirection info is added to support the global global service redirection message of the IS-2000 wireless standard.

FIG. 9 is a diagram illustrating a specific format of the IS-2000 Redirection Record information element illustrated in FIG. 8, and FIG. 10 is a diagram illustrating a specific format of the Service Redirection Info information element illustrated in FIG. 8.

Referring to FIG. 9, the IS-2000 Redirection Record information element includes an A1 element identifier (1 octet), a length (2 octets), a redirection record type (3 octets), and a transition. Redirection Record Length (4 octets), Redirection Record Contents (5 octets to j octets).

Referring to FIG. 10, the Service Redirection Info information element includes an A1 element identifier (1 octet), length (2 octets), reserved (7,6,5 bits of 3 octets), and Excl_P_Rev_Ind ( 3 octets 4 bits), Redirect_P_REV_Incl (3 octets 3 bits), Redirect Type (3 octets 3 bits), Reserved (3 octets 1 bit), Return If Fail (0 octets of 3 octets), REDIRECT_P_MIN (4 octets) ), REDIRECT_P_MAX (5 octets).

The fields of the service redirection info message according to the embodiment of the present invention shown in FIG. 10 are basically designed for the same purpose as the fields in the extended global service redirection message shown in FIG. 2. Therefore, detailed description thereof will be omitted.

Next, the operation of providing service switching between the 1x EV-DO HRPD system and the future 1x EV-DV system will be described according to an embodiment of the present invention. It will be described here only when the packet origination is raised to the CDMA2000 1X system, and only the operation of switching the packet origination to the 1x EV-DO HRPD system in the same region, but the principle of the present invention is not limited thereto. do.

11 is a view showing a RECORD_TYPE field of an extended global service switch message according to an embodiment of the present invention.

Referring to FIG. 11, a record type field of “00000101” added to a field of an extended global service switching message as shown in FIG. 4, which is a message defined in the existing IS-2000.5 signaling standard, is included. have. The present invention additionally indicates Record Type = 00000101 in addition to the currently defined record type value so that when the packet is sent to the CDMA2000 1X system, the packet is switched to the 1x EV-DO HRPD system adjacent to the CDMA2000 1X system. Characterized in that.

In the case of a dual mode terminal capable of receiving both services of the CDMA2000 1X system and the 1x EV-DO system, monitoring the paging channels of the terminal 1X system and the 1x EV-DO system, respectively. This can lead to battery waste. Therefore, after a certain time, monitoring the paging channel of the 1x EV-DO system is turned off and the dual mode terminal is operated only as a 1X system. Therefore, it is a reasonable approach to operate only 1X in other cases except packet transmission. In such a case, the present invention configures the RECORD_TYPE field of the extended global service switching message as shown in FIG. 11 so that when the dual mode terminal uses the packet transmission to the 1X system, the 1x EV-DO system adjacent to the 1X system is provided. Packet switching is made.

FIG. 12 is a diagram illustrating an extended field according to an embodiment of the present invention in a RECORD_TYPE value of the extended global service switch message illustrated in FIG. 11. That is, FIG. 12 shows what information helps the service switch from the 1X system to the 1x EV-DO system when Record Type = 00000101.

Referring to FIG. 12, the RECORD_TYPE information element of the extended global service switch message includes fields of BAND_CLASS (5 bits), EXPECTED_SID (15 bits), EXPECTED_NID (16 bits), EXPECTED_PZID (8 bits), and NUM_CHANS (4 bits). Is done. The field of NUM_CHANS enables generation of a CDMA_CHAN field (11 bits) and a RESERVED field (0 to 7 bits).

As shown in FIG. 12, the RECORD_TYPE information element according to an embodiment of the present invention includes fields of a system identifier (SID), a network identifier (NID), and a packet zone identifier (PZID). Include them. In addition, since the 1x EV-DO system may use a different frequency from that of the 1X system, the 1x EV-DO system includes a band class field. In addition, a channel number (CDMA_CHAN) and a number (NUM_CHAN) for indicating the number of channels that can be received in the corresponding band are included.

FIG. 13 is a diagram illustrating a processing flow of an NDSS providing operation between a CDMA2000 1X system and a 1x EV-DO HRPD system according to an exemplary embodiment of the present invention. This processing flow represents the packet origination switching procedure from CDMA2000 1X to 1x EV-DO HRPD. The procedure is as follows.

(Step 100a) The dual mode mobile terminal (Dual MS / AT) receives and examines a CDMA2000 1X random system and selects an origination message to a serving BS (BS-1). Up.

The service base station BS-1 sends a CM Service Request message to the exchange MSC-1 in step 100b. At this time, MSC-1 performs user registration and authentication according to standard methods. The exchange is more suitable for another 1x-EV DO HRPD system according to the subscriber's preference information (for example, 1x EV-DO packet transmission preference) registered in a system device such as a subscriber authentication center or a home location register (HLR). If the current serving base station can provide NDSS, the exchange can decide to originate the dual mode terminal to another 1x EV-DO HRPD system.

The exchange MSC-1 sends a service switch message to the serving base station BS-1 to perform the NDSS operation (step 100c).

In step 100d, the service base station BS-1 informs the dual mode terminal of the switching information received from the exchange to send a packet to the 1x EV-DO system through a service switching message.

(Step 100e) The dual mode terminal transmits a packet as described in IS-878 (1x EV-DO HRPD IOS).

Meanwhile, in the detailed description of the present invention, specific embodiments have been described, but various modifications are possible without departing from the scope of the present invention. Therefore, the scope of the present invention should not be limited to the described embodiments, but should be determined not only by the scope of the following claims, but also by the equivalents of the claims.

As described above, the present invention newly defines signaling procedures and messages in the base station system for service switching between the CDMA2000 1X 3G system and the IS-95 A / B 2G system. Accordingly, the present invention allows the service switching between the CDMA2000 1X system and the IS-95 A / B system to be provided in the base station and the exchange system in the same manner as the radio section. In addition, the present invention extends the existing scheme to provide service switching between the 1x EV-DO HRPD system and the future 1x EV-DV system so that the dual mode terminal can send packets from the CDMA2000 1X system to the 1x EV-DO HRPD system. do.

Claims (2)

In a mobile communication system comprising a mobile terminal, a first base station supporting voice service, and a second base station supporting voice service and data service simultaneously, the terminal receives a service from the first base station and the second base station. In the method of switching the service of the mobile terminal when in a common area, Determining whether call congestion occurs at the second base station when there is voice transmission from the terminal to the second base station; And switching the voice transmission from the terminal to the first base station when it is determined that call congestion has occurred in the second base station. In a mobile communication system comprising a mobile terminal, a first base station supporting voice service, and a second base station supporting voice service and data service simultaneously, the terminal receives a service from the first base station and the second base station. In the method of switching the service of the mobile terminal when in a common area, Determining whether there is a packet transmission for data service from the terminal to the first base station; And when the first base station determines that the packet is originated, the first base station converts the voice transmission from the terminal to the second base station.