JP2002261777A - Radio mobile communication terminal, radio communication system, and radio communication method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To rapidly move among different networks. SOLUTION: The radio mobile communication network 1 that can freely travel among a plurality of networks detect such position information as the latitude, longitude, and altitude of itself, based on a signal that is transmitted from a GPS satellite 15, compares the position information with the agent information of all agents that are stored by itself and are updated periodically, recognizes the agent of the network that the itself belongs currently, and perform communication via the recognized agent.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless mobile communication terminal, a wireless communication system, and a wireless communication method, and more particularly, to a wireless mobile communication terminal that performs communication via at least one intermediary communication device existing in each network, The present invention relates to a wireless communication system and a wireless communication method.

[0002]

2. Description of the Related Art At present, communication protocols on the Internet are TCP / IP (Transport Control Protocol).
/ Internet Protocol) has become mainstream. This TC
In a group of networks using P / IP, each network has at least one router serving as a communication mediation device. A communication terminal is connected to a router in each network, and the communication terminal communicates via the router. Communication information transmitted to a router is divided into basic units called IP packets (IP datagrams), and an IP address is added to a header of the IP packet. The IP address is like an address (hereinafter, referred to as an address) that can clearly identify which network a certain communication terminal is connected to, and a network prefix indicating a network address,
And a host prefix indicating the address of the communication terminal.

[0003] A router plays a role of transferring an IP packet transmitted from one communication terminal to another router or the other communication terminal which is a final destination. Specifically, the transfer destination is determined by comparing the network prefix of the IP address added to the IP packet with a routing table, for example, communication path control information, and the IP packet is transferred toward the destination.

[0004] In a communication process with a portable wireless mobile communication terminal (hereinafter, referred to as a mobile terminal) that is movable between a plurality of networks as a final destination, the mobile terminal is separated from a network to which the mobile terminal was originally connected. Let's consider the case of moving to another network. At this time, since the network prefix of the IP packet received by the router existing on the network to which the mobile terminal was originally connected is different from the network prefix of the network to which the mobile terminal has moved, the router transmits the received IP packet to the mobile terminal. Cannot be transferred to

[0005] This will be described below with reference to the schematic configuration of the network shown in FIG. In FIG. 5, a communication terminal that communicates with a mobile terminal 110 that can move freely between networks, the communication terminal fixed to the network is referred to as a fixed terminal 109, and the network to which the fixed terminal 109 is connected is referred to as a fixed terminal. It is assumed that the network is 100. Also, the mobile terminal 11 which is the final destination of the IP packet
Network 0 is originally connected to network 2
00. The network to which the mobile terminal 110 has moved is referred to as a network 300.

Here, a router 101 is installed on the network 100, a router 102 is installed on the network 200,
A router 103 is installed on the top of the router 103.

The network prefix of the network 100 is set to 100.0.0, and the network 2
Assuming that the network prefix of 00 is 200.0.0 and the network prefix of the network 300 is 300.0.0, the IP address of the fixed terminal 109 is, for example, 100.0.0.
The ten IP addresses are, for example, 200.0.0.1.

When the fixed terminal 109 communicates with the mobile terminal 110, the router 101 receives the IP packet transmitted from the fixed terminal 109, and receives the IP packet attached to the IP packet.
The IP packet is transferred to the router 102 by matching the network prefix 200.0.0 of the P address 200.0.0.1 with a route table, for example, communication route control information. The router 102 checks the IP of the received IP packet
The transfer to the mobile terminal 110, which is the final destination, is determined by matching the network prefix 200.0.0 of the address 200.0.0.1 with the communication path control information, but the transfer destination originally exists. Should be mobile terminal 1
Since the device 10 is absent, the IP packet cannot be transferred. Therefore, the mobile terminal 110 cannot receive the IP packet transmitted by the fixed terminal 109 on the network 300.

As a technique for solving such a problem,
For example, MobileIP has been proposed. Mobil
eIP is a mobile terminal 110 that uses MobileIP.
Is a technology that makes it appear as if it is located at a predetermined address on the network to which it was originally connected when viewed from another terminal (for example, the fixed terminal 109) regardless of where it is connected on which network. MobileIP is IE
RFC2 at TF (Internet Engineering Task Force)
002 is standardized.

A communication process of a mobile terminal using MobileIP will be described with reference to a schematic configuration of a network shown in FIGS. 6 and 7, a network to which the fixed terminal 109 that has transmitted the IP packet is connected is referred to as a network 100. The network to which the mobile terminal 110 which is the final destination of the IP packet is originally connected is referred to as a network (hereinafter, referred to as a home network) 200. The network to which the mobile terminal 110 has moved is referred to as a network (hereinafter, referred to as an external network) 300.

Here, a router 101 is installed on the network 100, and the home network 200
Above is a router called a home agent
Described as a home agent. ) 102 is installed, and a router called an external agent (hereinafter, referred to as an external agent) is provided on the external network 300.
103 is installed.

The network prefix of the network 100 is set to 100.0.0, and the network prefix of the home network 200 is set to 200.0.0.
0.0, and the network prefix of the external network 300 is 300.0.0. Then, the IP address of the fixed terminal 109 is, for example, 100.0.
0.1, and the IP address of the mobile terminal 110 is, for example, 200.0.0.1. That is, IP address 2
0.0.0.1 is the home address of the mobile terminal 110.

First, position registration of mobile terminal 110 will be described with reference to FIG. In FIG. 6, the external agent 103 broadcasts its existence as an agent advertisement at certain time intervals. This is to ensure that the mobile terminal 110 can be connected to the external network 300 to which the foreign agent 103 belongs at any time. When the mobile terminal 110 moves to the foreign network 300, the mobile terminal 110 receives the agent advertisement in the foreign network 300, thereby discovering the foreign agent 103. Here, the mobile terminal 110
Recognizes that it belongs to the external network 300 where the external agent 103 exists, that is, performs location registration. Next, the mobile terminal 110
It requests the external agent 103 to register its own location. The foreign agent 103 receives the request, registers the location of the mobile terminal 110,
The home agent 102 is notified of the location registration information of the mobile terminal 110. Thereby, the home agent 102 registers the location of the mobile terminal 110.

It is also possible that the mobile terminal 110 actively transmits an agent request for searching for an agent existing on the destination network, for example, the external agent 103 on the external network 300 at a certain time interval. In this case, the foreign agent 103 transmits an agent advertisement in response to the agent request, and the mobile terminal 110 can discover the foreign agent 103 by receiving the agent advertisement. Also in this case, the mobile terminal 110
Performs location registration based on the agent advertisement, requests the foreign agent 103 to register itself, and in response to the request, the foreign agent 103 registers the location of the mobile terminal 110 and performs home location registration. The location registration information of the mobile terminal 110 is notified to the mobile terminal 102, and the home agent 102 registers the location of the mobile terminal 110.

Next, the transfer processing of the IP packet will be described with reference to FIG. Fixed terminal 109 is mobile terminal 1
When communicating with the fixed terminal 10, the router 101
9 is compared with the network prefix 200.0.0 of the IP address 200.0.0.1 attached to the IP packet and a routing table, for example, communication route control information. To the home agent 102. Here, the home agent 102 receives the IP packet as a proxy, encapsulates the IP packet in a new IP address to the foreign agent 103 based on the location registration information of the mobile terminal 110 held by the home agent 102, Transfer by so-called tunneling. The foreign agent 103 restores the transferred IP packet to its original form and transfers it to the mobile terminal 110 that is the final destination. Therefore, the mobile terminal 110
Can receive, on the moved external network 300, an IP packet that would originally be received on the home network 200.

Conversely, the IP packet transmitted from mobile terminal 110 to fixed terminal 109 is transmitted to home agent 102
, But directly to the router 101. At this time, the mobile terminal 110 sets the IP address attached to the IP packet to the home address 200.0.
0.1, the mobile terminal 1
10 appears to be connected to the home network 200.

As described above, the mobile terminal 110 that has moved
Is connected to the external agent 103 using an agent advertisement or an agent request.

In Japanese Patent Laid-Open No. 2000-92562, communication is performed between base stations (access points), location information of mobile terminals is shared between base stations, and another base station adjacent to one base station is used. A technique is disclosed in which, when a mobile terminal is connected to a coverage area of an external agent, an external agent accommodating one base station shortens the time to carry out an agent advertisement.

[0019]

By the way, the above-mentioned agent advertisement or agent request is performed at certain time intervals. Therefore, the connection time of the mobile terminal using the agent advertisement or agent request,
There is a problem that it takes more time than the channel switching (handoff) during communication in the link layer, and the mobile terminal does not move smoothly between networks. Further, if the certain time interval is too short, there is a problem that the ratio of the agent advertisement occupied in the traffic in the network increases, and the efficiency of the network (hereinafter, referred to as throughput) decreases.

In the technique disclosed in Japanese Patent Laid-Open No. 2000-92562, since communication is performed between base stations, it is necessary to introduce a system for realizing this technique to all base stations. Yes, it would be very expensive in terms of cost. Further, JP-A-2000-9
According to the technology disclosed in the 2562 publication, when a mobile terminal is connected to the coverage area of another base station adjacent to one base station, a foreign agent accommodating one base station requires many agent advertisements. Therefore, if the mobile terminal does not move within the coverage area of one base station, frequency resources will be wasted. In addition, it is considered that the throughput is significantly reduced during the period in which the agent advertisement is transmitted.

Accordingly, the present invention has been proposed in view of the above circumstances, and has as its object to provide a wireless mobile communication terminal, a wireless communication system, and a wireless communication method capable of moving between networks at high speed. I have.

[0022]

SUMMARY OF THE INVENTION In order to achieve the above object, a wireless mobile communication terminal according to the present invention is movable between a plurality of networks and communicates with each other via communication mediation devices existing in each network. A wireless mobile communication terminal that performs communication, and stores position information detection means for detecting its own position information, and communicable area information indicating at least an area in which the communication mediation device can communicate with respect to all communication mediation devices. Recognizing means for comparing the position information detected by the position information detecting means with the communicable area information stored in the storing means, and recognizing the communication mediation device existing in the network to which the device belongs. And communication control means for performing communication via the communication mediation device recognized by the recognition means.

This wireless mobile communication terminal is movable between a plurality of networks, and exists in a located network based on detected position information and stored communicable area information of a communication mediating device. Recognize communication mediation devices,
The communication is performed via the communication mediation device.

[0024] The wireless communication system according to the present invention comprises:
In order to achieve the above object, in a plurality of networks, at least one communication mediation device in each network, position information detecting means for detecting its own position information, and at least the communication mediation device for all communication mediation devices A storage unit that stores communicable area information indicating a communicable area by the intermediary device, and compares the own position information detected by the position information detection unit with the communicable area information stored by the storage unit, A recognition unit for recognizing a communication mediation device existing in a network to which the device belongs, and a communication control unit for performing communication via the communication mediation device recognized by the recognition unit are provided, and are movable between a plurality of networks. And a wireless mobile communication terminal that performs communication via a communication mediation device existing in the network.

In this wireless communication system, the wireless mobile communication terminal is movable between a plurality of networks,
Based on the detected position information and the stored communicable area information of the communication mediation device, the communication mediation device existing in the located network is recognized, and communication is performed via the communication mediation device.

Further, in order to achieve the above-mentioned object, the wireless communication method according to the present invention provides a communication mediation device in which at least one wireless mobile communication terminal capable of moving between a plurality of networks exists in each network. A wireless communication method of performing communication via a wireless communication terminal, wherein a position information detecting step of detecting position information of the wireless mobile communication terminal, and all of the stored wireless information and the position information of the wireless mobile communication terminal detected in the position information detecting step A communication step of comparing the communication mediation device that is present in the network to which the wireless mobile communication terminal belongs, and a communication mediation device recognized by the recognition process, And a communication control step of performing communication via the control unit.

This wireless communication method is capable of moving between a plurality of networks, and based on the detected position information and the stored communicable area information of the communication mediation device, the communication existing in the located network. A wireless mobile communication terminal that recognizes the mediation device performs communication via the communication mediation device.

[0028]

Embodiments of the present invention will be described below in detail with reference to the drawings. In this embodiment, a wireless communication system includes a wireless mobile communication terminal (hereinafter, referred to as a mobile terminal) that can move in a plurality of networks, and a router that is at least one communication mediation device in each network. Consists of The mobile terminal has a position information detecting means for detecting its own position information,
Storage means for storing location information of all agents, network range, and data of identifiers (IP addresses and the like) (hereinafter, referred to as agent information); detected location information and agent information of all stored agents; And a communication control means for communicating through the recognized agent.

Hereinafter, a schematic configuration of the mobile terminal will be described with reference to FIG. The mobile terminal 10 uses a GPS (Global Posit
ioning System) signal receiving antenna 22, GPS signal receiving unit 23, wireless signal transmitting / receiving antenna 24, wireless signal transmitting / receiving unit 25, agent database 26,
CPU (Central Processing Unit) 27 and ROM (R
ead Only Memory) 28 and RAM (Random Access Mem)
ory) 29. Further, the mobile terminal 10
An operation unit 30, a display unit 31, a microphone 32,
A so-called user interface such as a speaker 33 may be provided. In that case, a control unit (not shown) for controlling these devices is required.

In the mobile terminal 10 configured as described above, each component functions as follows. In the mobile terminal 10, the GPS signal receiving unit 23 receives GPS signals transmitted from a plurality of GPS satellites via the GPS signal receiving antenna 22 and detects position information. The wireless signal transmitting / receiving unit 25 transmits / receives a wireless signal via the wireless signal transmitting / receiving antenna 24 and performs modulation / demodulation and the like. The agent database 26 is composed of agent information of all agents. This agent information is periodically broadcast from each agent and updated. The CPU 27 controls the operation of each unit constituting the mobile terminal 10. The ROM 28 stores a program for controlling the operation of each unit executed by the CPU 27 and the like. RAM
Reference numeral 29 denotes a work area used for storing and developing data.

The operation unit 30 is an interface through which operations such as information input to the mobile terminal 10 are performed. The display unit 31 is, for example, a liquid crystal display (LCD: Liquid Cry).
stalDisplay) to display various information. The microphone 32 detects an audio signal. Speaker 33
Outputs an audio signal. A control unit (not shown) controls the operation of a machine interface including an operation unit 30, a display unit 31, a microphone 32, a speaker 33, and the like.

As described above, in the mobile terminal 10 in which each component functions, the GP signal received by the GPS signal
The position information is detected based on the S signal, and the RAM 29 stores the agent information of all the agents constituting the agent database 26, based on the detected position information and the stored agent information of all the agents. The CPU 27 recognizes an agent on the network to which the CPU 27 belongs, and transmits the
7 communicates via the agent by transmitting and receiving wireless signals.

FIG. 2 shows a schematic configuration of a network including a wireless communication system. In FIG. 2, a communication terminal that communicates with a mobile terminal 10 that can move freely between networks, where the communication terminal fixed to the network is a fixed terminal 9, and the network to which the mobile terminal 9 is connected is Network 1 is assumed. The home network 2 is a network to which the mobile terminal 10 capable of receiving a GPS signal from the GPS satellite 15 is originally connected. Here, the network to which the mobile terminal 10 is originally connected is the network indicated by the network prefix of the IP address held by the mobile terminal 10. Further, among a plurality of networks to which the mobile terminal 10 moves, for example, two networks are respectively referred to as a first external network 3 and a second external network 4.

A router 11 is installed on the network 1, a router called a home agent 12 is installed on the home network 2, and a first foreign agent 13 is installed on the first external network 3.
A router called a second external agent 14 is installed on the second external network 4.

The network prefixes of the network 1, the home network 2, the first external network 3, and the second external network 4 are each 1.0.
0, 2.0.0, 3.0.0, and 4.0.0. Then, the IP address of the fixed terminal 9 is, for example, 1.
0.0.1, and the IP address of the mobile terminal 10 is, for example, 2.0.0.1. This IP address 2.0.
0.1 is called the home address of the mobile terminal 10.

In such a plurality of networks,
When the mobile terminal 10 moves between different networks (for example, the home network 2 and the first foreign network 3), the mobile terminal 10 needs to change the IP address, and thus the IETF (Internet Engineering Task Forc.)
e) Mobil standardized as RFC 2002 in
eIP is used.

On the other hand, a case where the mobile terminal 10 moves in the same network will be described below using the schematic configuration of the links in the home network 2 and the first external network 3 shown in FIG. In the link shown in FIG. 3, in the home network 2, a plurality of routers, for example, routers 16 ₁ , 1
6 ₂ is connected, it is installed apart access points. In this case, a plurality access points to the router 16 _1, for example, the access point ₁₇ 1, 17 ₂ are connected to the router 16 ₂ access points ₁₇ 3, 17 ₄ are connected.

[0038] Similarly, in the first external network 3, a plurality of routers to the first foreign agent 13, for example, the router ₁₆ 3, 16 ₄ is connected, the access point is located remotely. In this case, a plurality access points to the router 16 _3, for example, the access point 17
_5, 17 ₆ are connected, the access point ₁₇ 7, 17 ₈ is connected to the router 16 _4.

A home net having such a link configuration
In the work 2 and the first external network 3, for example,
When the mobile terminal 10 moves within the home network 2,
Mobile terminal 10 connects to the same home agent 12
Access point 17 ₁, 17₂, 17₃, 17
₄Between the mobile terminal 10 and the mobile terminal 10
The network prefix of the IP address changes
Will not be. Similarly, in the first external network 3
When the mobile terminal 10 moves, the mobile terminal 10
Access point connected to 1 external agent 13
17₅, 17₆, 17₇, 17₈Can be moved between
And the network of the IP address held by the mobile terminal 10.
The prefix will not change. Therefore,
For a mobile terminal 10 moving within the same network,
Channel disconnection during communication at link layer between access points
Replacement (hereinafter referred to as handoff).

Hereinafter, the location registration of the mobile terminal 10 in the network shown in FIG. 2 will be described in detail with reference to the flowchart shown in FIG. The mobile terminal 10
Is registered when the mobile terminal 10 moves to a new network instead of moving within the same network, so that the description of the access point used in the above-described handoff will be omitted. MobileIP is used so that the mobile terminal 10 can receive an IP packet on the first external network 3 or the second external network 4 away from the home network 2. Mo
In the bileIP, as a method for the mobile terminal 10 to detect movement between networks and register its own location,
Generally, agent advertisement and agent request are used. In the embodiment described below, the mobile terminal 1
The latter agent request is used for location registration of 0.

In FIG. 4, first, in step S1, the mobile terminal 10 is turned on and the like. Next, in step S2, when the agent database 26 is updated with the agent information of each agent broadcasted periodically from each agent, for example, once a day (YES), in step S5, the mobile terminal 10 The GPS signal transmitted from the GPS satellite 15 is transmitted to the GPS signal receiving antenna 22 via the GPS signal receiving antenna 22.
The PS signal is received by the PS signal receiving unit 23.

On the other hand, if the agent database 26 has not been updated in step S2 (NO), the mobile terminal 10 receives the broadcasted agent information in step S3, and in step S4, The agent database 26 is updated. Subsequently, in step S5, the mobile terminal 10 receives the above-described GPS signal.

In step S6, the mobile terminal 10
Based on the received GPS signal, position information such as the latitude, longitude, and altitude of the terminal is detected. Next, in step S7, the mobile terminal 10 compares the position information with the agent information of all the agents constituting the agent database 26, and searches for an agent on the network to which the mobile terminal 10 belongs.

In step S8, when the location registration described later has not been performed for the agent searched by the mobile terminal 10 (NO), in step S9, the mobile terminal 10 determines that the home agent 1
2 or not, that is, whether or not the network to which it belongs currently is the home network 2. If the current network is the home network 2 (YES), in step S10, the mobile terminal 10
It performs communication using its own home address as a so-called fixed terminal.

On the other hand, in step S9, the mobile terminal 1
0 indicates that the searched agent is the home agent 12
If not, that is, if the current network is not the home network 2 but another network, for example, the first external network 3 (NO),
In step S11, the mobile terminal 10 transmits an agent request to the first foreign agent 13 on the first external network 3 from the wireless signal transmitting / receiving unit 25 via the wireless signal transmitting / receiving antenna 24. The first foreign agent 13 immediately transmits an agent advertisement in response to the agent request, and in step S12, the mobile terminal 10 receives the agent advertisement. At this time, the agent advertisement is not broadcasted but transmitted to the mobile terminal 10 that transmitted the agent request. Subsequently, in step S13, the mobile terminal 10 sets 1 in the field of the received agent advertisement.
Then, the IP address of the first external agent 13 is read and obtained. This IP address is called a care-of address.

In addition, in step S8 described above, if the location registration described later has been performed for the agent searched by the mobile terminal 10 (YES), the mobile terminal 10 needs to change the agent in step S14. If it is determined whether or not there is a change, and if there is no need to change the agent (NO), that is, if the mobile terminal 10 has not moved from the network to which it currently belongs, in step S15, the mobile terminal 10 Use to communicate.

On the other hand, in step S14, when it is necessary to change the agent (YES), that is, when the mobile terminal 10 has moved from the network to which it currently belongs to another network, in step S9 described above,
It is determined whether the moved network is the home network 2 or not. When the moved network is the home network 2 (YES), in step S10, the mobile terminal 10 performs communication using its own home address as a so-called fixed terminal.

On the other hand, in step S9, if the moved network is not the home network 2 but is another network, for example, the second external network 4 (NO), the first foreign agent on the first external network 3 In step S11, the mobile terminal 10
Sends an agent request to the second external agent 14 on the second external network 4 via the radio signal transmitting / receiving unit 25
Through the wireless signal transmitting / receiving antenna 24. The second external agent 14 immediately transmits the agent advertisement in response to the agent request, and proceeds to step S1.
In 2, the mobile terminal 10 receives the agent advertisement. At this time, the agent advertisement is not broadcasted but transmitted to the mobile terminal 10 that transmitted the agent request. Subsequently, in step S13, the mobile terminal 10 determines the IP address of the second foreign agent 14 from one of the fields of the received agent advertisement.
Read and get the address. This IP address is called a care-of address.

As described above, the mobile terminal 10 may obtain a care-of address from the first foreign agent 13 and the second foreign agent 14. Hereinafter, the process is the same as the conventional process, and the description will be continued with the mobile terminal 10 that has acquired the care-of address from the first foreign agent 13 as an example. The mobile terminal 10 performs location registration using the acquired care-of address. Subsequently, the mobile terminal 10 requests the first foreign agent 13 that has transmitted the agent advertisement including the care-of address to also perform location registration. Upon receiving this request, the first foreign agent 13 registers the location of the mobile terminal 10 with itself, and notifies the home agent 12 of the location registration information of the mobile terminal 10. As a result, the home agent 12 registers the location of the mobile terminal 10 with itself. As described above, the home agent 12 and the first foreign agent 13 complete the location registration of the mobile terminal 10, so that the first
The foreign agent 13 can accurately transfer the IP packet received by proxy to the mobile terminal 10.

Next, the transfer process will be described in detail. When the fixed terminal 9 communicates with the mobile terminal 10, the router 11 receives the IP packet transmitted from the fixed terminal 9, and sets the IP address 2.0.
The IP packet is transferred to the home agent 12 on the home network 2 by matching the network prefix 2.0.0 of 0.1 with a route table, for example, communication route control information. Here, the home agent 12
Receives the IP packet on behalf of,
3 and the encapsulation performed in RFC2004 etc.
Transfer to the first external agent 13 by so-called tunneling. The first foreign agent 13 restores the encapsulation of the transferred IP packet to its original form and transfers the IP packet to the mobile terminal 10 as the final destination.

Conversely, the IP packet transmitted from the mobile terminal 10 to the fixed terminal 9 is not transferred through the home agent 12 but is transferred directly to the router 11.
At this time, even though the mobile terminal 10 is connected to the first external network 3, the
Since the address is set to the home address of 2.0.0.1, the mobile terminal 10 appears to the fixed terminal 9 as if it is continuously connected to the home network 2.
As described above, the mobile terminal 10 can perform communication using the care-of address in the moved network.

As described above, the mobile terminal 10
Communication is performed using any one of the home address, the currently held IP address, or the care-of address. However, there is a case where the mobile terminal 10 needs to change the IP address being used as it moves to another network. Therefore, while the power is kept on, the mobile terminal 10
Is repeatedly detected.

More specifically, the IP address used when the mobile terminal 10 performs communication is the home address in step S10, and the current IP address in step S15.
After the P address and the care-of address in step S13 are determined, the mobile terminal 10 continues to execute step S13.
In 2, it is determined whether or not the agent database 26 has been updated with the agent information of each agent broadcasted periodically from each agent, for example, once a day. Next, the mobile terminal 10 that has performed location registration at least once receives GPS signals at minute time intervals and detects location information. By quickly detecting location information, for example, the mobile terminal 10
Can be quickly determined whether or not has departed from the network to which he currently belongs. Thereby, the mobile terminal 10
Performs location registration again only when it departs from the network to which it currently belongs.

At this time, there is no need to compare the detected position information with the agent information of all the agents constituting the agent database 26, and the position information is located close to the agent on the network to which the agent has belonged. What is necessary is just to compare with the agent information of the agent. Thereby, the mobile terminal 10 detects an agent on the network to which the mobile terminal 10 currently belongs. If the detected agent is a foreign agent, the mobile terminal 1
0 sends an agent request to this external agent. Thereafter, as described above, the mobile terminal 10 receives the agent advertisement in response to the agent request,
The location is registered using the care-of address acquired from the agent advertisement, and communication is performed.

As described above, in the wireless communication system according to the embodiment of the present invention, the mobile terminal 10 constituting the wireless communication system has its own position information detected from the GPS signal and all the agents constituting the agent database 26. By comparing with the agent information, the agent on the network to which the terminal belongs can be quickly recognized. Thus, when the recognized agent is a foreign agent, the mobile terminal 10 can perform location registration and move at high speed between networks. In addition, the mobile terminal 10 uses the GP to detect its own location information.
By using S, the traffic of the agent advertisement in the network can be reduced, and the network resources can be used effectively.

In the embodiment of the present invention, the mobile terminal 10 detects its own position information by using GPS, compares the detected position information with the agent information of all agents, We recognized the agent of the existing network, and when the recognized agent was an external agent, we performed location registration using an agent request. However, when the GPS cannot be used for some reason, for example, when the GPS signal cannot be received, the mobile terminal 10 cannot perform the location registration. Therefore, the external agent can have a function of transmitting the agent advertisement in response to the agent request and a function of broadcasting the agent advertisement at certain time intervals.

Therefore, when the mobile terminal 10 cannot receive the GPS signal, it switches to the agent advertisement receiving mode, and determines which network it belongs to from the received agent advertisement. As a result, the mobile terminal 1
0 performs communication using its own home address as a so-called fixed terminal when it belongs to the home network 2. On the other hand, when belonging to the external network, the mobile terminal 10 reads out and acquires the care-of address from one of the fields of the agent advertisement. Thereafter, the mobile terminal 10 performs position registration using this care-of address and performs communication. As described above, in order to determine whether the GPS signal can be received, it is necessary to periodically confirm whether the GPS signal can be received. Also, the agent database 26 needs to be updated.

It should be noted that the present invention is not limited to only the above-described embodiment, and it is needless to say that various modifications can be made without departing from the gist of the present invention. For example, the GPS used in the embodiment of the present invention may be used for applications such as a conventional navigation system. Further, the mobile terminal targeted in the embodiment of the present invention may be a communication module or the like including a car navigation and a PC (Personal Computer) card. Furthermore, in the embodiment of the present invention, the mobile terminal detects its own position information using GPS, but may detect the position information by another method having an equivalent function.

[0059]

The wireless mobile communication terminal according to the present invention compares the detected location information of itself with the communicable area information indicating the communicable area of each communication mediating device stored therein, and at high speed belongs to the wireless mobile communication terminal. Communication mediation device existing in the network to be connected can be recognized. As a result, it is possible to perform position registration with respect to the recognized communication mediation device as needed, and to move at high speed between networks. In addition, by using GPS to detect its own location information, reduce the traffic of agent advertising in the network,
Network resources can be used effectively.

Further, in the wireless communication system according to the present invention, the wireless mobile communication terminal compares the detected position information of itself with the stored communication area information indicating the communication area of each communication mediating device, It is possible to quickly recognize a communication mediation device existing in a network to which the device belongs. As a result, it is possible to perform position registration with respect to the recognized communication mediation device as needed, and to move at high speed between networks. In addition, the GP
By using S, the traffic of the agent advertisement in the network can be reduced, and the network resources can be used effectively. Since there is no need to make any special changes to the communication mediation device or the like, there is no economic burden.

Further, in the wireless communication method according to the present invention, the wireless mobile communication terminal compares the detected location information of itself with the stored communicable area information indicating the communicable area of each communication mediating device. It is possible to quickly recognize a communication mediation device existing in a network to which the device belongs. As a result, it is possible to perform position registration with respect to the recognized communication mediation device as needed, and to move at high speed between networks. In addition, the GP
By using S, the traffic of the agent advertisement in the network can be reduced, and the network resources can be used effectively. Since there is no need to make any special changes to the communication mediation device or the like, there is no economic burden.

[Brief description of the drawings]

FIG. 1 is a block diagram showing a schematic configuration of a wireless mobile communication terminal according to an embodiment of the present invention.

FIG. 2 is a diagram illustrating a schematic configuration of a network including a wireless communication system according to an embodiment of the present invention.

FIG. 3 is a diagram illustrating a schematic configuration of a link of a network.

FIG. 4 is a flowchart showing a location registration process of the wireless mobile communication terminal according to the embodiment of the present invention.

FIG. 5 is a diagram illustrating a schematic configuration of a network including a wireless mobile communication terminal that does not use MobileIP.

FIG. 6 is a schematic configuration diagram of a network showing a location registration process of a wireless mobile communication terminal using MobileIP.

FIG. 7 is a schematic configuration diagram of a network showing an IP packet transfer process of a wireless mobile communication terminal using MobileIP.

[Explanation of symbols]

9 fixed terminal, 10 wireless mobile communication terminal, 11 router, 12 home agent, 13 first foreign agent, 14 second foreign agent, 15 GPS satellite, 23 GPS signal receiving unit, 25 wireless signal transmitting / receiving unit, 26 agent database, 27 CPU

Claims (22)

[Claims] 1. A wireless mobile communication terminal which is movable between a plurality of networks and communicates via each communication mediating device present in each network, comprising: a position information detecting means for detecting own position information; A storage unit that stores at least communicable area information indicating an area in which communication can be performed by the communication mediating device, for all communication mediating devices, Recognizing means for comparing the stored communicable area information and recognizing a communication mediating device present in the network to which the device belongs, and communication control means for performing communication via the communication mediating device recognized by the recognizing means. A wireless mobile communication terminal comprising: 2. The method according to claim 1, wherein the position information detecting means is a GPS (Global Pos.) Which is a current position measuring system using an artificial satellite.
2. The wireless mobile communication terminal according to claim 1, wherein the position information is detected by using a transition system. 3. The wireless mobile communication terminal according to claim 1, wherein the communicable area information is periodically broadcast from each communication mediating device and updated. 4. The communication device according to claim 1, wherein, if there is a communication mediation device recognized immediately before, the recognizing unit compares the location information with the communication mediation device information existing in the vicinity of the communication mediation device recognized immediately before. 2. The wireless mobile communication terminal according to claim 1, wherein the communication is performed. 5. The communication control unit, when the communication mediation device recognized by the recognition unit is the same as the communication mediation device to which the communication mediation device was originally connected, communicates with the communication mediation device to which the communication mediation device was originally connected. The wireless mobile communication terminal according to claim 1, wherein communication is performed using an address. 6. The communication control means, when the communication mediation device recognized by the recognition means is different from the communication mediation device to which the communication mediation device was originally connected, requests connection to the communication mediation device recognized by the recognition means. The wireless mobile communication terminal according to claim 1, wherein the terminal transmits information. 7. The communication mediation device transmits a response message to the wireless mobile communication terminal that has transmitted the connection request information in response to the connection request information. 7. The wireless mobile communication according to claim 6, wherein request information is transmitted, a communication address is obtained from the response message transmitted from the corresponding communication mediation device, and communication is performed using the communication address. Terminal. 8. A plurality of networks, at least one communication mediation device existing in each network, position information detecting means for detecting its own position information, and at least communication between all communication mediation devices by the communication mediation device. Storage means for storing communicable area information indicating a possible area, and comparing the own position information detected by the position information detection means with the communicable area information stored by the storage means, Recognition means for recognizing a communication mediation device that exists in the network to which the device belongs, and communication control means for performing communication via the communication mediation device recognized by the recognition means, wherein the communication mediation device is movable between the plurality of networks, A wireless communication system comprising: a wireless mobile communication terminal that performs communication via a communication mediation device existing in each network. 9. The wireless communication system according to claim 8, wherein said position information detecting means detects position information using GPS which is a current position measurement system using said artificial satellite. 10. The wireless communication system according to claim 8, wherein the communicable area information is periodically broadcasted from each communication mediating device and updated. 11. When there is a communication mediation device recognized immediately before, the recognizing means compares the location information with the communication mediation device information of the communication mediation device present in the vicinity of the communication mediation device recognized immediately before. The wireless communication system according to claim 8, wherein the communication is performed. 12. The communication control means, when the communication mediation device recognized by the recognition means and the communication mediation device to which the wireless mobile communication terminal was originally connected are the same, the wireless mobile communication terminal is originally connected. 9. The wireless communication system according to claim 8, wherein communication is performed using the communication address of the communication mediation device that has been set. 13. The communication control device, when the communication mediation device recognized by the recognition device is different from the communication mediation device to which the wireless mobile communication terminal was originally connected, to the communication mediation device recognized by the recognition device. The wireless communication system according to claim 8, wherein the connection request information is transmitted to the wireless communication system. 14. The wireless communication system according to claim 13, wherein the communication mediation device transmits a response message to the wireless mobile communication terminal that has transmitted the connection request information according to the connection request information. . 15. The communication control unit transmits the connection request information, acquires a communication address from the response message transmitted from a corresponding communication mediation device, and performs communication using the communication address. The wireless communication system according to claim 14, wherein: 16. At least one wireless mobile communication terminal capable of moving between a plurality of networks is provided in each network.
What is claimed is: 1. A wireless communication method for performing communication via a communication mediation device, comprising: a position information detecting step of detecting position information of the wireless mobile communication terminal; and the wireless mobile communication terminal detected by the position information detecting step. Comparing the location information with the communicable area information indicating the area communicable by all of the stored communication mediating devices, and recognizing a communication mediating device present in the network to which the wireless mobile communication terminal belongs; A communication control step of performing communication via the communication mediation device recognized in the recognition step. 17. The wireless communication method according to claim 16, wherein in the position information detecting step, the position information is detected by using a GPS, which is a current position measurement system using an artificial satellite. 18. The wireless communication method according to claim 16, wherein the communicable area information is periodically broadcast from each communication mediating device and updated. 19. In the recognizing step, when there is a communication mediation device recognized immediately before, the comparison based on the position information is performed based on the communicable area information of the communication mediation device existing near the communication mediation device recognized immediately before. The wireless communication method according to claim 16, wherein the method is performed. 20. In the communication control step, when the communication mediation device recognized in the recognition step is the same as the communication mediation device to which the wireless mobile communication terminal was originally connected, the wireless mobile communication terminal is originally 17. The wireless communication method according to claim 16, wherein communication is performed using a communication address of the connected communication mediation device. 21. In the communication control step, when the communication mediation device recognized in the recognition process is different from the communication mediation device to which the wireless mobile communication terminal was originally connected, the communication mediation recognized in the recognition process is different. 17. The wireless communication method according to claim 16, wherein the connection request information is transmitted to the device. 22. The communication mediation device, according to the connection request information, transmits a response message to the wireless mobile communication terminal that has transmitted the connection request information. 22. The wireless communication method according to claim 21, wherein request information is transmitted, a communication address is obtained from the response message transmitted from the corresponding communication mediation device, and communication is performed using the communication address. .