JP2003229800A - Mobile terminal, mobile communication system and method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce electric power for paging mobile terminals. <P>SOLUTION: A mobile IP (Internet Protocol) network 1', without having to page functions and a PHS (Personal Handyphone System) network 10' are used. Mobile terminals have functions of 802.11b and the PHS, the functions of 802.11b connect the mobile terminals to the IP network 1' via base stations of the 802.11b. The PHS network 10' may be a normal type and has paging function. A home agent has a function of paging mobile terminals by using a gateway 20 to the PHS network 10', when CoA (Care of Address) of mobile terminals are not active, in addition to functions owned by the home agent in the IP network 1'. The addresses of the mobile terminals in the PHS network 10' are managed as telephone numbers in the PHS by the home agent. When the mobile terminals are at standby, the mobile terminals maintain communication enabled state to the PHS and suspend to communicate to the 802.11b. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a mobile terminal having a plurality of network interfaces, a mobile communication system and a communication method.

[0002]

2. Description of the Related Art In a mobile communication system, it is necessary to know the exact position of a mobile terminal before starting the transmission of data (including voice, video, etc.), and a paging service is used as a means for that purpose. . The paging service means a function of calling another party. There is a trade-off between how accurately the current position of the mobile terminal is tracked and the time and complexity it takes. The position of the mobile terminal is held in the network and updated upon the movement of the mobile terminal or the firing of the timer. Based on this information, the paging service sends a communication request to the set of base stations that are likely to have the mobile terminal to be searched. This set of base stations is called a paging area and is composed of a set of adjacent base stations.

In a network supporting paging, a mobile terminal can have two states. One is the "active" state, which allows location tracking with the finest granularity, for example the current base station. In this state, paging is unnecessary. The other state is the "standby" state. In the "standby" state, coarse-grained position tracking is performed for each paging area. The mobile terminal updates the location information to the network in the "standby" mode much less frequently than in the "active" state. The power consumed to update the network is much higher than the power consumed in the "standby" state. When you are in communication standby, you can reduce the update frequency by putting it in the "standby" state.
We are trying to reduce the battery consumption of mobile terminals.

The paging service is an essential function in a mobile communication system, and is a CDMA (Code Division M
Ultimate Access) and GPRS (General Packet Radio Sys
Paging service is implemented in the existing high frequency mobile communication system such as tem).

On the other hand, IP (Internet Protocol) telephones are coming to a practical stage. The introduction of IP network technology is progressing not only in fixed telephones but also in mobile communication systems. By using the IP network technology, it is possible to reduce system construction and management costs, and it is possible to provide higher-performance services because data and voice can be handled in unison. It is expected to become the mainstream of 3rd and 4th generation mobile communication systems.

In addition, the introduction of IP network technology is 80
2.11x, Bluetooth, etc. will bring about the diversification of the wireless communication system of the mobile communication system (the term of wireless network is also used as appropriate). 802.11x is a LAN (Local Area N)
etwork) standard, 2.4GHz band or 5G
The contents are a wireless LAN and a wireless LAN using a spread spectrum method in the Hz band. 802.11x
Includes several standards in more detail (x = a, x = b, etc.), but will be collectively referred to herein as 802.11x. Bluetooth is a short-distance data communication technology and has a maximum data transmission rate of 1 Mbit / sec and a maximum transmission distance of 10 m. In fact, by installing a wireless LAN access point such as 802.11x, there is a movement to provide a high-speed wireless communication system in a limited area called a hotspot (for example, a wireless access point is installed in a hamburger shop). It has begun.

[0007]

However, in the past, paging architectures and protocols were designed for each wireless network, and they were incompatible. If there is paging at the IP level such that the location is managed as the movement of the IP address instead of each wireless network, a paging service that does not depend on the type of wireless network becomes possible. However, even if an IP-based paging service can be realized, it is not easy to incorporate it into a paging service integrated with an existing wireless network when a new wireless network is introduced. Newly emerging wireless networks are not easy to integrate because they use proprietary protocols and lack of validation. In addition, since the mobile terminal moves to the IP layer, which is higher than the radio layer, for position registration with the base station while moving in the “standby” state, there is a problem that power consumption for paging increases.

[0008] Furthermore, it is expected that the number of mobile terminals that implement a plurality of wireless network interfaces will increase in the future. For example, even today, PDC (Persona) is used as a mobile terminal equipped with multiple network interfaces.
l Digital Cellular), PHS (Personal Handyphone Sy
stem) that supports both types of terminals. However, in this type of terminal, PDC and PHS perform paging independently.

When mobile terminals equipped with more network interfaces come out in the future, paging to each wireless network causes a problem from the viewpoint of power consumption and effective use of network resources. Therefore, even if the paging target is limited and the location registration is performed only on one optimal network at a certain moment, in the case where the wireless coverage areas are alternated, the location information is frequently updated and the power consumption is reduced. Increase. Also, the hot spot service mentioned above has a small coverage area,
Although there are needs such as wanting to use because of high speed and low usage fee, there are cases where it is wasteful to always try to register the location.

As described above, when the mobile terminal of the mobile communication system is equipped with a plurality of network interfaces, paging in each network causes a problem of power consumption of the terminal. Also, when a new type of wireless network appears, the cost of linking it with an existing wireless network becomes a problem. On the other hand, there is a demand to use the best wireless network available at that time.

In addition, in the transitional period of IP of the mobile communication network, a paging method that is broadly compatible cannot be made, or even if such a paging method can be made, it takes time until it becomes popular. There is a risk of this.

Therefore, an object of the present invention is to use a desired one of a plurality of wireless networks included in a mobile terminal and to reduce power consumption associated with paging, a mobile terminal, a mobile communication system and communication. To provide a method.

Another object of the present invention is to provide a mobile terminal and a mobile communication system capable of paging until a paging method is established only in an IP-based wireless network such as mobile IP, or even when the paging method is not established. And providing a communication method.

Still another object of the present invention is to provide a mobile terminal, a mobile communication system and a communication method which can selectively use a hotspot type network and a wide area public network.

[0015]

In order to solve the above-mentioned problems, the invention of claim 1 is a mobile terminal in a mobile communication system, which has at least first and second network interfaces. Is a mobile terminal used for communication and the second network interface is used for paging.

The invention of claim 9 has a first network and a second network, various services are provided to a mobile terminal via at least the first network, and a home agent of the first network is provided. Is a mobile communication system in which a call is made to a mobile terminal via a second network, and the mobile terminal registers address information with a home agent.

According to a tenth aspect of the invention, in the communication method, the mobile terminal is provided with the first and second network interfaces, and the service is provided to the mobile terminal via the first network interface. In this communication method, a call is made to the mobile terminal via the interface, and the mobile terminal registers address information via the first network interface to complete the call.

In the present invention, the network used for paging and the network actually used for communication are separated. The mobile terminal comprises these network interfaces. During communication standby, the interface of the paging network is put in a standby state and the interface of the communication network is stopped. This enables power saving. Further, by using a public wireless network as a paging network, paging of a new network becomes possible even when the bases such as base stations of a new network such as a mobile IP network are not sufficiently prepared. . Furthermore, the paging network can be used for communication as necessary, and an appropriate network can be used.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION Before describing an embodiment of the present invention, a summary of the present invention will be given. In the present invention, the network used for paging (calling) and the network actually used for communication are handled separately. The mobile terminal in the mobile communication system of the present invention has two or more network interfaces.
In principle, one or more of them is a network interface that supports paging. In relation to the network used for communication, a network that supports paging is preferably one that has low power consumption, is stable, has a wide service area, and already has a base. In relation to the network used for paging, the network used for communication is preferably one that enables high-speed communication and has a limited area. However, the present invention can be applied to a mobile terminal having only a network without paging, in order to realize a standby state at a hot spot without moving.

The mobile terminal maintains a communicable state with respect to a network that supports paging while waiting for communication. That is, it maintains an "active" or "standby" state for that network. In the case where multiple networks support paging, there are cases in which communication is possible for all of those networks, and for reasons such as reducing power consumption and restrictions on network resources, It is also possible not to maintain the communicable state for some of the networks. Further, paging may be fixed to a specific wireless network in the entire system.

When the paging network is fixed, that network is always used when paging a mobile terminal. When the network used for paging can be freely selected, the home agent (in the case of mobile IP) manages which network the mobile terminal is currently paging. In the wireless communication system according to the present invention, each mobile terminal is assigned a home address that does not depend on the position of the wireless network in use. The data addressed to the home address of a certain mobile terminal is intercepted by the home agent and transferred to the current position of the mobile terminal.

A home agent may exist for each mobile terminal, but a plurality of mobile terminals can be handled by one home agent. The home agent transfers the current position on the network for communication of the mobile terminal and the current position on the network for paging (or the last updated position) to transfer the data addressed to the home address. It holds as information for each mobile terminal together with information indicating whether the position information is currently valid.

When an attempt is made to call a telephone service from one mobile terminal to another mobile terminal, or when an attempt is made to notify a mobile terminal of the arrival of an electronic mail or an event from a server on the network, those senders are sent. Sends data to the home address of the mobile terminal that is the recipient. The home agent that captures the data sends a call request to the current location of the paging network.

The paged mobile terminal checks the currently available networks, including the paged network, among the installed network interfaces (the network having the paging function and the network not having the paging function). In this case, it is possible to prioritize the network search based on the usage status, cost, speed, and the like. When the caller requests the network quality and speed, it can be transmitted as additional information when paging and is used as a hint when the receiving terminal selects the network. When a usable network is found, first, a communication-enabled state is established with the network.

The home agent sends the first data packet from the sender to the mobile terminal and the communication is started.

By the above method, paging can be performed by using the paging function of a conventional network even in an environment in which a paging method has not been developed, is not equipped even if developed, or has no unified method. It will be possible. As a result, network development and construction costs can be significantly reduced. Further, in a mobile terminal having a plurality of network interfaces, it is not necessary to perform paging on all the interfaces, so there is a great effect on power saving of the mobile terminal.

The IP of the mobile system network
It is considered that mobile terminals that support both conventional wide area wireless networks (PHS, PDC, W-CDMA, etc.) and IP will become the mainstream in the transition period of the shift to commercialization. In such a mobile terminal, it is possible to solve the power consumption problem caused by moving to the IP layer by paging, by leaving the paging portion as the division of roles for utilizing the assets of the conventional wide area wireless network.

The present invention described above will be described in more detail with reference to one embodiment. FIG. 1 shows an example of a mobile communication system to which the present invention can be applied. In FIG.
Reference numeral 1 is a core network. Reference numeral 10 is another network. Various services 2 are transmitted via the core network 1 to mobile terminals MT1, MT2, ...
Provided for MTn. For example, a service 2 such as a telephone function, a mail function, and an internet access function is provided.

The core network 1 includes home agents HA1, HA2, ... for managing mobile terminals.
., HAn is provided. The wireless base station BS and the mobile terminals MT1, MT2, ..., MTn can communicate with each other via the wireless communication unit 3. That is, the mobile terminal MT1
~ MTn receives these services by communicating with one or a plurality of wireless base stations accessible from among a plurality of wireless base stations BS. Among these services, the home agent HA is required to provide services with asynchronous notification.
1 to HAn manage the current positions of the mobile terminals MT1 to MTn, respectively.

FIG. 2 shows a mobile communication system according to an embodiment of the present invention. One embodiment is a system in which a mobile IP network 1 ′ having no paging function is used as the core network 1, and a PHS network 10 ′ having a paging function is used as the other network 10. That is, the PHS network 10 'is fixedly used as the paging network.

The mobile terminals MT1 to MTn have 802.11b and PHS as wireless network interfaces. 802.11b connects the mobile terminals MT1 to MT to the mobile IP network 1 ′ via the 802.11b radio base station BS.
Connect n. The PHS network 10 'is for ordinary public services and has a paging function as standard. The behaviors of the mobile IP network and the PHS network, which are not particularly described here, are in accordance with their specifications.

The home agents HA1 to HAn use the gateway 20 to the PHS network 10 'when the CoA (Care of Address) of the mobile terminal is not valid in addition to the function of the home agent in mobile IP. , Has a function of calling a mobile terminal.
In one embodiment, the addresses of the mobile terminals MT1 to MTn in the PHS network 10 ′ are managed by the home agents HA1 to HAn as PHS telephone numbers. If the PHS interface is not replaced, this number is fixed for the mobile terminal.

In one embodiment, as shown in FIG.
The operation of communicating from the mobile terminal MT1 to the mobile terminal MT2 will be described. The present invention is applied to the mobile terminal MT2. FIG. 3 is a flowchart showing the operation of the mobile terminal MT2 at the start of the standby state. FIG. 4 is a flowchart showing the call request process of the home agent. FIG. 5 is a flowchart showing a process when the mobile terminal MT2 receives a call request. Note that the mobile terminal MT1 is a CN (Correspon
It acts as a dent node) and does not have to be a mobile unit.

In FIG. 2, ST0 is a mobile terminal MT2.
Indicates a state in which communication can be received from an unspecified number of terminals or servers (for example, a call waiting state of a telephone function). FIG. 3 shows an operation in which the mobile terminal MT2 shifts to a communication acceptable state (standby state) after communication is completed. Power saving can be realized by transitioning to the standby state. After the communication is completed and a predetermined time determined by a timer or the like elapses, the transition to the standby state is started (step S1).

If registration with the home agent HA is possible via the base station BS, in step S2,
Home Agent H that communication CoA is invalid
Register with A. If that is not possible, the home agent HA is sent to Co via the PHS gateway 20.
Tell A's invalidity. In step S3, the mobile terminal MT2
Puts the PHS network interface into a "standby" state and shuts down the 802.11b interface. In this way, the transition to the standby state (power saving state) is completed (step S4). Even in this standby state, a call can be made via the PHS network 10 '.

When the mobile terminal MT1 communicates with the mobile terminal MT2, first, as shown by the route ST1 in FIG. 2, a data packet is first sent to the home address of MT2, and the corresponding home agent HA2 sends the data packet. To capture. Step S in the flowchart of FIG.
11 corresponds to this processing.

In step S12, the home agent HA judges whether the mobile terminal MT2 is in the communicable state by 802.11b by looking at the held CoA. If the CoA is valid and can be communicated, the data is transferred to the CoA (step S13). Thus, the calling process is completed (step S14). The mobile terminal MT1 communicates with MT2 according to the Mobile IP protocol specifications.

In the home agent HA, when the mobile terminal MT2 has completed the transition to the standby state and its CoA is determined to be invalid in step S12, the mobile terminal MT2 is passed through the PHS gateway 20.
Call the PHS interface in the "standby" state (step ST2 in FIG. 2 and step S1 in FIG. 4).
5).

In step S16, it is determined whether or not the call has succeeded (in other words, whether or not the CoA registration has been accepted). If it is determined that the call is successful, step S13 (processing for transferring a packet to CoA) is performed. In case the call fails,
The calling process fails (step S17).

Next, the processing when the mobile terminal MT2 receives the call request via the PHS network 10 'will be described with reference to FIGS. The first step S21 in FIG. 5 means that a call is made via the PHS network 10 '.

The mobile terminal MT2 sees the caller number information and finds that it is a call request from the PHS gateway 20. In step S22, the mobile terminal M
The 802.11b network interface of T2 is activated, and an accessible base station BS is searched for by referring to the radio wave condition, the identifier and the like. In step S23, CoA
Is obtained and it is determined whether the CoA registration is successful.

As shown by the route ST3 in FIG. 2, when the base station BS is found, CoA is acquired according to the mobile IP protocol and registered in the home agent HA. This completes the calling process (step S24). By including the identifier of the mobile terminal MT1 in the request of the PHS gateway 20, it is possible to set whether to receive the call according to the caller. This setting is
It is possible by the user of the mobile terminal MT2.

If no accessible 802.11b base station is found in step S23, an IP connection via the access point of the PHS network 10 'is tried by setting in step S25. The setting here is a setting as to whether or not communication is performed using PHS, and is an internal setting of the mobile terminal MT2.
By including the identifier of the mobile terminal MT1 in the call request, it is possible to decide whether or not to make the PHS connection depending on the caller.

Filtering using information other than the caller identifier is also possible. For example, filtering can be performed using information such as the application used and the user identifier of the mobile terminal MT1. The home agent HA can perform the filtering by having the home agent side have such filtering information.

When the setting of the mobile terminal MT2 is such that communication is not performed using PHS, a call process failure process (step S27) is performed. When the mobile terminal MT2 is set to communicate using PHS, the determination process of step S26 is performed. In step S26, C via the PHS access point
It is determined whether the acquisition of the oA and the registration of the CoA are successful.

If it is determined in step S26 that CoA acquisition and registration are not successful, that is, 802.11b.
If no base station is found and PHS connection is not made, or if the call is rejected, call failure processing is performed (step S27). In this process, the route ST in FIG.
As indicated by 4, the failure is notified to the home agent HA 2 via the PHS gateway 20 together with the error reason. When the PHS terminal (mobile terminal MT2) cannot be paged in the PHS network 10 ′,
An error is returned from the PHS gateway 20 to the home agent HA. If upstream communication cannot be performed, such as when using a pager (registered trademark) network instead of the PHS network 10 ', a failure is determined by a timeout process.

In step S23 or S26, C
When the acquisition of oA and the registration of the CoA are successful, the home agent HA accepts the registration of the CoA and transfers the data packet from the mobile terminal MT1 to the address. After that, the mobile terminals MT1 and MT2
Means to start communication according to normal mobile IP specifications.

In the above-described operation, when the mobile terminal MT2 tries to enter the communication standby state, the PHS interface is stopped and the 802.11b network interface is set to the standby state because the PHS network 10 'cannot be accessed. It is also possible to register a valid CoA with the home agent HA. However, in this case, there is a problem that power consumption cannot be reduced.

The above procedure is performed by the PHS network 10 '.
It is also possible to replace the part with a PDC network, a W-CDMA network, or a pager network and apply it as it is.

Next, another embodiment of the present invention will be described. As shown in FIG. 6, another embodiment is a mobile terminal M.
The present invention is applied when T2 has a wireless interface of Bluetooth and 802.11b. Bluetooth and 8
02.11b is mobile I via each radio base station.
Connect the mobile terminal to the P network 1 '. Bluetooth
When compared with 802.11b, 802.11b can communicate faster than Bluetooth and has stronger radio waves, while Bluetooth
Is more power efficient than 802.11b, so the call is Blu
It is preferable that the communication is performed using etooth and the communication is performed using 802.11b. That is, communication is performed using a network different from the call in terms of transmission speed. In the figure, Bluetooth is abbreviated as BT as appropriate. The network may be switched in consideration of the stability of communication.

In another embodiment, the mobile terminal may have a mobile IP compatible paging function,
You don't have to have it. If it does not have a paging function, it cannot support movement. Mobile IP
If you have a paging function that supports it, you can support paging during movement by using that interface. Even if paging is not supported, it is possible to obtain a significant reduction in standby power by using it in a standby state in an area such as a hot spot. Here, we will explain an example where Bluetooth has a paging function.

The operation of the other embodiment will be described by taking as an example the operation of communicating from the mobile terminal MT1 to the mobile terminal MT2, like the operation of the above-described embodiment. The mobile terminal MT1 is a CN (Corresponden
It acts as a t Node) and does not have to be a mobile.

In FIG. 6, ST10 is a mobile terminal MT.
Reference numeral 2 indicates a state in which communication can be received from an unspecified number of terminals or servers (for example, a call waiting state of a telephone function). FIG. 7 shows an operation in which the mobile terminal MT2 shifts to the communication acceptable state (standby state) after the communication is completed.
In step S31, when it is detected by a timer or the like that a predetermined time has elapsed after the communication is completed, the transition to the standby state is started.

When the mobile terminal MT2 is in a state of accepting communication from an unspecified number of terminals and servers (for example, a call waiting state of a telephone function), the Bluetooth interface is selected as a paging network and the Bluetooth is selected.
CoA is acquired (step S32).

If a call is received, it is determined in step S33 whether or not communication is performed by Bluetooth. When it is desired to communicate by Bluetooth, in step S34, the CoA of Bluetooth is registered in the home agent HA as an effective address of the network for communication (step S3).
4). Then, in step S35, 802.11b is stopped as a wireless interface, and Bluetooth is set to a standby state.

In step S33, the Bluetoot
If it is decided not to use h for communication, step S
At 37, the home agent HA has a communication CoA
Is invalidated, and the Bluetooth CoA is registered as the calling CoA (step S37). And step S
The processing shifts to 35. The home agent HA manages both the CoA for communication and the CoA for calling. In this way, transition to the standby state (step S3)
6). The standby state is a power saving state because 802.11b is stopped and Bluetooth is in a standby state.

When a call request is received, if the user desires to use 802.11b, or if he / she wants to decide which one to use in the situation when the request comes, paging (calling) the home agent HA.
Register CoA as the position in the network for
Put the uetooth interface in standby. In either case, the 802.11b interface is brought down.

When the mobile terminal MT1 communicates with the mobile terminal MT2, as shown by the route ST11 in FIG. 6, first, a data packet is sent to the home address of the mobile terminal MT2, and the home agent HA sends MT1. Captures data from and starts MT2 call processing. Step S41 in the flowchart of FIG. 8 corresponds to this process. The processing shown in FIG. 8 is performed by the home agent.

In step S42, the home agent sends a valid CoA to the communication address of the mobile terminal MT2.
Is registered or not is determined. C for valid communication
When it is determined that the oA is registered, the packet is transferred to the address (step S43), and thereafter, the mobile terminals MT1 and MT2 perform communication according to the normal mobile IP protocol. Thus, the calling process is completed (step S44).

When the home agent HA determines in step S42 that the communication CoA of the mobile terminal MT2 is not valid, it is determined in step S45 whether the calling CoA is valid. Bluetooth
And, for calling using the mobile IP network, CoA for calling is introduced. If it is determined that the calling CoA is valid, the Bluetooth interface is in the standby state, and thus the Bluet indicating the paging position is displayed.
A call request is sent to the CoA address of ooth (step S46, route ST12 in FIG. 6).

In step S47, it is determined whether or not the call has succeeded (in other words, whether or not the registration of the CoA for communication has been accepted). If it is determined that the call is successful, step S43 (processing for transferring a packet to the communication CoA) is performed. When the call fails, and when it is determined that the CoA for calling is not valid, the call process fails (step S
The process of 48) is performed.

Next, regarding the processing when the mobile terminal MT2 receives a call request via Bluetooth,
This will be described with reference to FIGS. 6 and 9. The first step S51 in FIG. 9 means that a call is made via Bluetooth.

In step S52, the mobile terminal MT2
Upon receiving the request, determines whether to perform communication by Bluetooth. If it is set to communicate using Bluetooth, the calling process is completed (step S55).

When it is determined in step S52 that communication is to be performed using the 802.11b network, the mobile terminal M
The 802.11b network interface of T2 is activated, and an accessible base station BS is searched (step S53). If the base station BS is found, Mobile IP
The CoA is acquired according to the protocol of the above, and the acquired CoA is used as the communication CoA by the home agent H.
Register in A (route ST13 in FIG. 6). Step S5
At 4, it is determined whether the acquisition and registration of the communication CoA is successful. If successful, the calling process is completed (step S55).

In step S54, the CoA for communication is used.
If it is determined that acquisition and registration are not successful, step S
At 56, it is determined whether to communicate by Bluetooth. When it is decided to perform communication by Bluetooth, the calling process is completed (step S55). Blue
When communicating by tooth, Bluetooth CoA is registered in the home agent HA. The home agent HA transfers the data from the mobile terminal MT1 to this address and communication is started.

If it is determined in step S56 that communication is not performed using Bluetooth, call failure processing is performed (step S57). In this process, as shown in FIG.
As indicated by a route ST14 in the figure, the home agent HA is notified of the failure together with the error reason via the Bluetooth base station.

Similar to the one embodiment, in another embodiment, by including the identifier of the mobile terminal MT1 in the call request, it is possible to determine whether to accept the call according to the caller. This setting is for the mobile terminal MT
It can be set by two users.

In another embodiment, when 802.11b also has a paging function, it is possible to select 802.11b when there is no Bluetooth base station BS during standby. In other embodiments, the roles of Bluetooth and 802.11b can be exchanged for operation. The network used for paging may be changed depending on the standby power of the network device, the communication status of the network at the standby location, and the like.

In another embodiment, 802.11a and Bluetooth can be used in other networks such as 802.1
There is no problem even if it is replaced with 1a, HyperLAN or the like.

The present invention is not limited to the above-described embodiment of the present invention and the like, and various modifications and applications are possible without departing from the gist of the present invention.

[0071]

As described above, according to the present invention, a conventional network is used even in an environment in which a paging system has not been developed, has been developed and has not been deployed, or has no unified system. You can perform paging by using the paging function of
Network development and construction costs can be significantly reduced. Further, in a mobile terminal having a plurality of network interfaces, it is not necessary to perform paging on all the interfaces, which has a great effect on power saving of the mobile terminal.

In the transition period of IP, the conventional wide area wireless network (PHS, PDC, W-CD) is used.
It is considered that mobile terminals that support both MA (e.g. MA) and IP mobile networks will become mainstream. In such a mobile terminal, it is possible to solve the problem of power consumption caused by moving to the IP layer by paging, by leaving the paging portion as the division of roles for utilizing the assets of the conventional wide area wireless network.

Further, although the network can be used only in a limited area such as a hot spot, it is possible to effectively use a network that is desired to be used when it can be used because of high speed and low cost.

[Brief description of drawings]

FIG. 1 is a block diagram of an example of a mobile communication system to which the present invention can be applied.

FIG. 2 is a block diagram showing a communication system according to an embodiment of the present invention.

FIG. 3 is a flowchart showing a transition operation of the mobile terminal to a standby state in the embodiment of the present invention.

FIG. 4 is a flowchart showing an operation of a call request of a mobile terminal according to the embodiment of the present invention.

FIG. 5 is a flowchart showing a process when the mobile terminal receives a call request according to the embodiment of the present invention.

FIG. 6 is a block diagram showing a communication system of another embodiment of the present invention.

FIG. 7 is a flowchart showing a transition operation of a mobile terminal to a standby state in another embodiment of the present invention.

FIG. 8 is a flowchart showing an operation of a call request of a mobile terminal according to another embodiment of the present invention.

FIG. 9 is a flowchart showing a process when a mobile terminal receives a call request in another embodiment of the present invention.

[Explanation of symbols]

HA, HA1-HAn ... Home agent, BS
... Base stations, MT1 to MTn ... Mobile terminals, 1 ...
・ Core network, 10 ・ ・ ・ Other network,
1 '... Mobile IP network, 10' ... PHS network, 2
0 ... PHS gateway

Claims (14)

[Claims] 1. A mobile terminal in a mobile communication system, comprising at least first and second network interfaces, said first network interface being used for communication and said second network interface being used for paging. Mobile terminal. 2. The mobile terminal according to claim 1, wherein the first network interface has a higher communication speed than the second network interface. 3. The mobile terminal according to claim 1, wherein the first network interface consumes more power than the second network interface. 4. The mobile terminal according to claim 1, wherein the second network interface has a wider service area than the first network interface. 5. The mobile terminal according to claim 1, wherein the power supply of the first network interface is turned off during communication standby. 6. The mobile terminal according to claim 1, wherein address information is registered via the first network interface when a call is made via the second network interface. 7. The mobile terminal according to claim 6, wherein address information is registered via the second network interface and communication is possible via the second network interface. 8. The mobile terminal according to claim 1, wherein the second network interface is a public wireless network. 9. A first network and a second network are provided, and various services are provided to the mobile terminal via at least the first network.
A mobile communication system in which a home agent of the network of (1) makes a call to the mobile terminal via the second network, and the mobile terminal registers address information with the home agent. 10. A communication method, wherein a mobile terminal comprises first and second network interfaces, and a service is provided to the mobile terminal via the first network interface, wherein the mobile terminal moves via the second network interface. A communication method in which a call is made to a terminal and the call is completed by the mobile terminal registering address information via the first network interface. 11. The communication method according to claim 10, wherein the first network interface has a higher communication speed than the second network interface. 12. The communication method according to claim 10, wherein the first network interface consumes more power than the second network interface. 13. The mobile terminal according to claim 10, wherein the second network interface has a wider service area than the first network interface. 14. The communication method according to claim 10, wherein address information is registered through the second network interface, and communication can be performed through the second network interface.