JP2003124941A - Bidirectional information originating type multicast communication system and its operating method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a bidirectional information originating type multicast communication system and its operating method which enables the bidirectional information origination from a base station and mobile terminals, possibly reduces the number of multicast communication channels and useless traffics, and enables the priority control of the multicast communication. SOLUTION: The system comprises a plurality of base stations (20) capable of bidirectional information origination with mobile terminals belonging to their respective service areas; a base station controller (10) for generally managing the plurality of base stations; and a mobile terminal group (30) which are movable, as desired, over the service areas of one or more base stations among the plurality of base stations, and capable of bidirectional information origination, and have information interpreting keys for sending/receiving multicast information to/from their respective base stations. A single channel taking a common frequency and code over the entire service area is employed for multicast channels, thereby possibly reducing the channel number and useless traffics.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bidirectional information transmission type multicast communication system capable of transmitting bidirectional information to a mobile terminal in a wireless section and an operating method thereof.

2. Description of the Related Art A multicast communication method for simultaneously providing the same information to a plurality of mobile terminals is becoming widespread. This is to distribute multicast information to mobile terminals included in the service area of the base station.

[0002] There is a demand for a wireless multicast communication method that does not use resources as much as possible and that has a simple management method and simple processing flow. Here, since the information transfer device called a home agent does not have a one-to-one correspondence with the direct information distribution area called a scope, two types of multicast group information management are required: "direct participation" and "transfer participation".
Mobile terminal is "direct participation group""transfer participation group"
A multicast communication method has been proposed in which three pieces of information of "non-participating group" must be managed (Japanese Patent Laid-Open No. 10-243010: Japanese Patent Application No. 09-39).
288). The communication method disclosed here has the problems that the processing is complicated and the information management load on the mobile terminal is high. Further, there is a method for relaying multicast communication between a plurality of networks, which is an improvement of the above-mentioned prior art (Japanese Patent Laid-Open No. 11-
220500: Japanese Patent Application No. 10-33856). Also here, since the method similar to the above-mentioned publication is adopted, there is a problem that the processing is complicated and the information management load on the mobile terminal is high. Further, a technique for realizing the multicast communication by an individual channel to each mobile terminal is also disclosed (Japanese Patent Laid-Open No. 2-212058).
No. 000-175250: Japanese Patent Application No. 10-34515
No. 5). This technique involves compression of the channel space and
Information is distributed to the area and the adjacent area for one mobile terminal (user). Therefore, there is a problem that the traffic becomes enormous because the data is distributed to a plurality of base station areas. Moreover, the modeling of the priority control method has not been clarified. Prior art defining multicast as a broadcast channel is also disclosed (Japanese Patent Laid-Open No. 2000-
175263: Japanese Patent Application No. 10-347549).
Here, the channel allocation method is CDMA (Code D
It is limited only to the ivision Multiple Access), and its application to other systems has not been clarified. In addition, a technique having commonality with TCP / IP by utilizing IGMP (Internet Group Management Protocol) is also disclosed (Japanese Patent Laid-Open No. 2000-2000).
-32007 gazette: Japanese Patent Application No. 11-106187).
However, here, the transmission method is IP Over wireless AT.
It is limited to M (asynchronous transfer mode), and it is difficult to apply it to other systems.

[0003]

The present invention enables bidirectional information transmission between a base station and a mobile terminal, reduces the number of channels for multicast communication and unnecessary traffic as much as possible, and enables priority control of multicast communication. It is an object to provide a two-way information transmission type multicast communication system and an operating method thereof.

[0004]

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention
Any one or more of a plurality of base stations capable of bidirectional information transmission with a mobile terminal belonging to each service area, a base station control device that collectively manages the plurality of base stations, and a plurality of the base stations. Of mobile terminals capable of arbitrarily moving in the service area of the base station and capable of transmitting and receiving bidirectional information, the mobile terminals having an information decryption key for transmitting / receiving multicast information to / from each base station. And a group, and is solved by a bidirectional information transmission type multicast communication system that reduces the number of channels and unnecessary traffic as much as possible by making the multicast channel a single channel using a common frequency and code throughout the service area. .

Another object of the present invention is to enable a mobile terminal belonging to a two-way information transmission type multicast communication system to request registration of multicast information only for its own multicast group using the information decryption key. Solved by a multicast communication system.

Further, the object of the present invention is to control each base station by the base station control device, reduce unnecessary multicast communication traffic, calculate network resources for priority control service at each level, and provide flexible control. It is solved by a multicast communication system that enables operation. According to the multicast communication system of the present invention, it is a bidirectional information transmission type, and desired multicast data can be acquired by a request issued from the mobile terminal side to the base station. In this case, the objective is to reduce the number of channels for multicast communication in the wireless section as much as possible, reduce unnecessary traffic as much as possible, and enable priority control of multicast communication. We manage each station area. The basic model of the multicast communication system of the present invention is shown in FIG. In this model of the multicast communication system, each mobile terminal has a key for decrypting the multicast communication of its own multicast group, and a terminal not having this key discards the received multicast communication information. Also, by using this key, each mobile terminal can request the registration of the multicast information only for the self-joined multicast group. In this model, the multicast channel is defined as a single channel that uses a common frequency and code throughout the service area, and the number of channels for multicast communication is determined by using this multicast channel to send and receive information related to multicast as much as possible. We are trying to reduce. Further, by allocating the multicast data device and the priority control device at the level of summarizing the base station and the level of the base station respectively, unnecessary multicast communication traffic as shown in FIG. 6 is reduced, and as shown in FIG. It enables network resource calculation and flexible operation for priority control service at each level.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The functional model structure of a multicast communication system according to the present invention is as shown in FIG. 1, and is roughly classified into a base station control stage 10, a base station group 20, and a mobile terminal group 30. .

The base station control stage 10 is composed of a plurality of base station groups 2
It is intended to control 0 as a whole, and is a block for controlling the entire service area.
2. A multicast service control device 14 and a priority control management device 16 are included.

The base station control device 12 includes the base stations A, B,
It has a role of notifying and registering the multicast group information notified from C and the multicast information from the mobile terminals belonging to each to the multicast service control device 14. Also, the multicast information is read from the multicast service control device 14 and transmitted to each base station A, B, C in the service area. And each base station A,
By requesting B and C to read out the individual base station area information and distribute it within the area, the multicast information distribution within the entire service area is controlled comprehensively. The multicast service control device 14 is a device for recording / holding multicast group subscription information (multicast group subscription information table) of each mobile terminal in the service area, and information commonly distributed to the entire service area. The priority control management device 16 interlocks with the base station control device 12 and the multicast service control device 14, calculates network resources in the service area based on the multicast group subscription information of the entire service area, and performs multicast communication addressed to each multicast group. Dynamically determines whether the priority given to the network is acceptable for network resources. The base station group 20 refers to a set of devices that control the inside of each of the base station areas A, B, and C. Each base station A, B, C manages the mobile terminal group 30 included in the base station area and its multicast group subscription information, and plays a role of notifying / registering to the multicast base station data devices A, B, C. . In addition, the multicast information distributed from the base station control device 12 or the multicast information read from the multicast base station data devices A, B, and C in response to a request from the base station control device 12 is used in a base station area by using a multicast channel. It plays a role of transmitting to each mobile terminal group 30 in A, B, and C. The multicast base station data devices A, B, C hold multicast group subscription information (intra-area multicast group subscription information table) of each mobile terminal group 30 in the base station areas A, B, C, and base station area individual information. It is a device that does. The base station priority control devices A, B, C operate in conjunction with the base stations A, B, C and the multicast base station data devices A, B, C, and according to the multicast group joining information in the base station area, Network resources are calculated, and it is dynamically determined whether or not the priority given to each multicast group or each mobile terminal addressed multicast communication is acceptable for the network resources.

With the mobile terminal group 30, a transmission / reception function for multicast communication and a multicast communication function On /
A mobile terminal device having an Off switching function.

As described above, the functional model of the multicast communication system according to the present invention comprises the base station control stage 10, the base station group 20, and the mobile terminal group 30. Hereinafter, a specific operation of the present invention will be sequentially described.

First, the definition of the multicast channel will be described.

The multicast channel is a 1-to-N (plurality) communication channel set between the base station and all mobile terminals in the base station areas A, B, and C. Regardless of the channel allocation method in the wireless section, the multicast channel uses a common and fixed channel in each service area. For example, CDMA (Co
de Division Multiple Access
ss), a channel having a certain frequency and code is defined as a multicast channel. If the traffic load is allowed, either the broadcast channel or the common control channel may be used as it is. Similarly,
TDMA (Time Division Multip
In the case of “le Access”, a channel of a certain fixed frequency is defined as a multicast channel, and the multicast communication is performed by adjusting the transmission / reception timing for each multicast group. When there is no room in the channel, the transmission / reception timing common to all the multicast group communications may be defined to use a single channel.
If the traffic load is allowed, either the broadcast channel or the common control channel may be used as it is. FDMA (Frequency Divi
In the case of the zone multiple access, a channel having a certain fixed frequency is defined as a multicast channel. When the traffic load is allowed, either the broadcast channel or the common control channel may be used as it is. As described above, the present invention can be used without depending on the channel allocation method by defining a single channel common to the service area that can communicate with all terminals in each base station according to each channel allocation method. Transmission / reception of multicast communication is performed as follows.

From the viewpoint of simplification of information management and security, it is assumed that the multicast group joining information of each mobile terminal of the terminal group 30 is decided in advance at the time of contract, and the information is managed by the multicast service control device 14. It is assumed that However, when the complexity of information management and the problem of security are solved, a dynamic new registration means for a multicast group may be possible. In that case, when each mobile terminal uses the means for notifying the base stations A, B, C of the multicast group joining information, when a new multicast group is designated, it is treated as new registration and the multicast service control device 1
4. Allow registration to the multicast base station data devices A, B, C.

Further, in a mobile terminal having a multicast function and joining a multicast group, by setting the multicast function On / Off of the mobile terminal,
It is assumed that transmission / reception of multicast communication can be dynamically changed. From the above, each mobile terminal can select the time when it is necessary and can efficiently perform the transmission and reception of the multicast communication without wasting unnecessary energy. The management of multicast group information is as follows. Management of the multicast group subscription information of each mobile terminal in each base station area is performed by each mobile terminal notifying the corresponding base station. At this time, the information essential for the notification is the terminal ID and the multicast group ID. The trigger for the notification is (a) the base station controller sends a multicast group join information request to each base station at regular intervals according to the required real-time property → each base station that has received the request sends its own base station. Send a multicast group join information request using a multicast channel in the station area → The multicast communication joining mobile terminal that received the request responds to the base station with its own multicast group join information, (b) Each mobile terminal sends its own multicast Responding group subscription information to the base station at regular intervals, (c) When each mobile terminal moves in the base station area and is authenticated in the new base station area, the new base station sends to the mobile terminal. Send a multicast group join information request using an individual channel → The multicast communication joining mobile terminal that received the request sends its own multicast Responsive strike group subscription information to the base station, one of the three, or shall be caused by a combination of these. At this time, a channel used for a multicast group joining information response from each mobile terminal to the base station is a multicast channel or an individual channel depending on the response trigger. In other words, when the information request is made at regular intervals, capturing the individual channel by each mobile terminal puts pressure on the channel space.
It is more effective to define the multicast channel as a bidirectional channel and use the multicast channel. However, if each mobile terminal is individually requested for information only when it moves to the new base station area, and if the information is not updated as long as it stays within the same base station area, the multicast channel is transmitted from the base station to each mobile terminal. It is also possible to define it as a one-way channel and use a dedicated channel for the multicast group join information response. When the multicast channel is defined as a bidirectional channel, it is necessary to control the order of uplink communication from each mobile terminal to the base station.
For this order control, random, round robin,
WRR (Weighted Round Robin)
Various known priority control methods can be applied. As an example, it will be disclosed with reference to FIG. 2, which shows a case where a multicast channel is used for a multicast group join information response. Note that the same components as those in FIG. 1 are denoted by the same reference numerals, the ○ mark of the mobile terminal group indicates multicast communication joining, the X mark indicates multicast communication non-joining and non-receiving, and the solid line arrow indicates multicast. Indicates communication (wireless section). Here, a flow of multicast group management is shown in the case where the information request is made from the base station controller 12 at a fixed cycle as a trigger for notification of multicast group subscription information. (A) The base station controller 12 has service areas A, B,
The multicast group joining information of all mobile terminals in C, the information about each multicast group, and the information about each terminal are registered in the multicast service control device 14. (B) The base station controller 12 transmits a multicast group joining information request to each of the base stations A, B, and C. (C) The base stations A, B, and C that have received the request transmit a multicast group joining information request to all mobile terminal groups in their own base station areas A, B, and C using the multicast channel. (D) Each mobile terminal receiving the request is a multicast communication subscriber terminal and has a multicast function On / O.
If the ff setting is On, a multicast group join information response is created according to the request and transmitted to the corresponding base station. This response includes its own terminal ID and multicast group ID. At this time, a mobile terminal existing in an area extending over a plurality of base station areas must respond to all base stations that have transmitted the request. (E) Of the mobile terminals that have received the request, non-subscriber terminals for multicast communication or multicast function On /
A terminal whose Off setting is Off does not process all the information transmitted by the multicast channel.
Alternatively, it shall be discarded after reception. Also, the request received here is not similarly processed for reception, or is discarded after reception. (F) The base stations A, B, and C are addressed to the base station control device 12,
The received multicast group joining information response and its own base station area ID are transmitted. (G) The base station controller 12 compares the information contained in the received multicast group join information response with the information held in the multicast service controller 14. (H) If the terminal ID and the multicast group ID included in the response are a combination registered in the multicast service control device 14, the base station control device 12 determines as the information corresponding to the terminal ID and the multicast group ID included in the response. The area ID is registered in the multicast service control device 14. Also, it sends a request to register the multicast group joining information to the base station of the response sender. This registration request includes the area ID, the terminal ID, and the multicast group ID. (I) In the case of a network that does not allow dynamic new registration to a multicast group, the terminal ID included in the response
And the multicast group ID is a combination not registered in the multicast service control device 14, the base station control device 12 discards the response or transmits an error response to the base station of the response transmission source. This error response includes the area ID, the terminal ID, and the multicast group ID. (J) In the case of a network that allows dynamic new registration to a multicast group, if the combination of the terminal ID and the multicast group ID included in the response is not registered in the multicast service control device 14,
The base station controller 12 queries the multicast service controller 14 for the terminal information and the multicast group information. As a result of the inquiry, when the problem for the dynamic new registration is solved, the base station controller 12 informs the multicast service controller 14 of the area ID as the information corresponding to the terminal ID and the multicast group ID included in the response. register. The problem for dynamic new registration includes whether or not the multicast group permits dynamic new registration, a billing problem for the terminal, and the like. Also, it sends a request to register the multicast group joining information to the base station of the response sender. This registration request includes the area ID, terminal ID, and multicast group I.
D shall be included. Either discard the response or send an error response to the base station that sent the response. This error response includes the area ID, the terminal ID, and the multicast group ID. As a result of the inquiry, if the problem for the dynamic new registration is not solved, the base station controller 1
2 discards the response or transmits an error response to the base station which is the source of the response. This error response includes the area ID, the terminal ID, and the multicast group ID. (K) The base stations A, B, and C that have received the registration request have the terminal ID and the multicast group ID included in the registration request.
Are registered in any of the multicast base station data devices A, B, and C attached thereto. (L) When any of the base stations A, B, and C that has received the error response subsequently receives the same multicast group joining information response, it is discarded. Management of the multicast group information is realized by the above processing. In addition, multicast group information group key management / distribution is performed as follows. In the present invention, each multicast group has a code serving as a group key, and at the time of transmitting each multicast information, information coded (encrypted) by this code is transmitted. By using this group key, only the multicast communication subscribing terminals that have joined the multicast group can receive and decrypt the information. Since the present invention does not depend on the content of the coding (encryption) method using this group key, the type of the code (encryption) method is not particularly limited. A group key is defined for the multicast group one to one throughout the service area. The distribution method of the group key is defined as (a) fixedly according to the height of the demand for security, and the group key of the multicast group is distributed to the subscribing terminals at the time of the multicast communication contract, (b) dynamic change to·
When a multicast group joining information response is accepted, the group key of the multicast group is distributed by an individual channel for each joining terminal. (C) Dynamically changing / defining, except for communication. It is realized by any one of the means for appropriately distributing the group key of the multicast group for each subscribing terminal.

As an example, FIG. 3 shows a case in which the group key is dynamically changed / defined and distributed for each subscribing terminal through an individual channel. The same components as those in FIG. 1 are designated by the same reference numerals, and ○ in each area indicates a multicast communication joining terminal, × indicates a multicast communication non-joining and non-receiving terminal, and a solid arrow Indicates individual channel communication (wireless section). The flow of group key management and distribution in this case is shown below. (A) The base station controller 12 uses a group key for each multicast group (indicated by% group name in FIG. 3,
For example, the group key of group 1 is% 1), and the code is registered in the multicast service control device 14. (B) When the base station controller 12 changes the group key, the base station controller 12 registers each base station area A, B, C in the multicast service controller 14.
Inquiring about the multicast group joining information of, the group key of the required multicast group is transmitted for each base station. Base stations A, B, which have received the changed group key,
C registers the group key in the multicast base station data devices A, B, and C attached thereto. (C) Base stations A, B, which have received the changed group key,
The C inquires of the multicast base station data devices A, B, and C about the multicast group joining information, and distributes the group key to all the mobile terminals that have joined the multicast group by an individual channel. (D) When receiving the registration request from the base station controller 12 in response to the multicast group join information response from the mobile terminal, the base stations A, B, and C distribute the group key to the mobile terminal by the individual channel. At this time, in the multicast group information management, when a method of requesting information only to a new mobile terminal is used, distribution is performed to all mobile terminals for which registration is requested. However, if the method of requesting information to all mobile terminals at regular intervals is used, distribution is performed to all mobile terminals requested to be registered, or multicast group joining in the multicast base station data device is performed. The information may have a group key distribution flag, and may be distributed only to undistributed terminals. (E) The mobile terminal group which has received the group key has a table for registering the group key for each self-added multicast group, and registers and manages the received group key information. The multicast group information group key management / delivery is realized by any one of the above processes. Next, the multicast information distribution will be disclosed. The distribution of the multicast information is managed and controlled by the base station control device 12, and each base station A, B, C that receives the multicast information transmission request from the base station control information is managed by its own base station area A, B, C. It is realized by transmitting multicast information using a multicast channel inside. In the present invention, as multicast information, (a) exactly the same information is distributed in the entire service area, (b) the same type of information to be distributed in the entire service area, and the information actually distributed is a base station. It is possible to define two types, different for each area. Examples of the delivery of exactly the same information include simultaneous notification of wide area information to all mobile terminals, and when the type of information is the same and the actually delivered information differs for each base station area, Information about shops belonging to the group can be considered. The former information is held in the multicast service control device 14, and the latter information is held in each multicast base station data device A, B, C. As an example of information distribution, the case where exactly the same information is distributed in the entire service area is shown in FIGS. 4 and 5, and the type of information to be distributed in the entire service area is the same and the content of the information that is actually distributed is the base. FIG. 6 shows a case where it differs for each station area. In each figure, the same components as those in FIG. 1 are denoted by the same reference numerals, ○ in each area indicates a multicast communication joining terminal, × indicates a multicast communication non-joining and non-receiving terminal, and A solid line arrow indicates multicast channel communication (wireless section). The flow of multicast information distribution in each case is shown below. (A) The base station control device transmits a multicast information transmission request to each base station. The transmission request includes the multicast group ID and the message ID. Message I
It is assumed that D is a different ID for each transmission request, and is a systematic ID that can identify the type of information requested to be transmitted and the device holding the information. At this time, if exactly the same information is distributed throughout the service area (Figs. 4 and 5)
Reads the information itself to be transmitted from the multicast service control device 14, adds it to the transmission request, and transmits it. However, a transmission request is not issued to a base station that does not have a terminal that joins the multicast group requested to be transmitted. (B) The base stations A, B, and C that have received the multicast information transmission request transmit the multicast information to all mobile terminals in their own base station areas A, B, and C by the multicast channel. At this time, when the group key corresponding to the requested multicast group ID is read from the multicast base station data devices A, B, and C, and the same information is distributed in the entire service area (FIGS. 4 and 5).
Is the information added to the transmission request, the information type is the same and the actually distributed information is different for each base station area (FIG. 6), the information corresponding to the information type indicated by the message ID is the multicast base station data. It is assumed that the information is read from the devices A, B, and C, the information is encrypted by the group key, and the information is transmitted together with the message ID and the multicast group ID. In the figure, the information encrypted by the group key is represented by msg * group key name. For example, msg *% 1 indicates information encrypted with the group key 1. (C) The mobile terminal receiving the multicast information encrypted by the group key
To check whether it is a self-joined multicast group. If it is not a self-added multicast group, the received information is discarded. (D) Further, the mobile terminal holds the message ID of the multicast information that has undergone the reception process, and upon receiving the multicast information, reads the message ID and confirms whether it is already received information. Message I of received information
If it matches D, the received information is discarded. By this processing, when exactly the same information is distributed in the entire service area, it is possible to avoid that the mobile terminals existing in an area extending over a plurality of base station areas receive the same information redundantly. Also, if the type of information is the same and the information that is actually distributed differs for each base station area, mobile terminals existing in areas that span multiple base station areas must receive all information for each base station area. Is possible. (E) When the received multicast information holds the self-joined multicast group ID and the unreceived message ID, the mobile terminal decrypts the received multicast information using the group key corresponding to the multicast group, Performs service processing such as screen display. The above processing realizes the multicast group information distribution that is simple, efficient, and reduces unnecessary traffic as much as possible. Also, the registration of multicast information from the mobile terminal is performed as follows. The present invention realizes bidirectional information transmission type multicast communication. Specifically, it is assumed that the information distributed as multicast information can be set not only by network side devices such as the base station control device 12 but also by mobile terminals. The actual multicast information distribution itself does not depend on the device or terminal for which the information has been set, but is carried out at the request of the base station control device, thereby simplifying management. As an example, FIG. 7 shows a case where a mobile terminal registers information in a multicast group to which exactly the same information is distributed in the entire service area. FIG. 8 shows a case where information is registered in a different multicast group for each base station area. In each of these figures,
The same reference numerals are given to the same constituent elements as in, the circles in each area indicate the multicast communication participating terminals, the crosses indicate the multicast communication non-participating and non-receiving terminals, and the solid arrows indicate the multicast channel communication. (Wireless section) is shown.

The flow of multicast information distribution when registering information for a multicast group to which the same information is distributed in the entire service area will be described below. (A) The mobile terminal sends a multicast information registration request for the self-added multicast group to the base station. The registration request includes its own terminal ID, multicast group ID, and information to be registered. (B) The base station that received the registration request confirms the multicast group ID included in the registration request, and if the same information is distributed in the entire service area, adds the area ID and adds the base station to the base station. A registration request is transmitted to the control device 12. However, the multicast group ID included in the registration request is inquired to the multicast base station data devices A, B, and C, and if the result of the inquiry is that the multicast group has no subscriber terminal in the base station, the registration request is issued. Discard. (C) The base station controller 12, which has received the registration request, receives the terminal ID and the multicast group ID included in the registration request.
Is checked with the multicast service control device 14 to confirm whether the mobile terminal of the request transmission source has joined the multicast group. If the result of the confirmation is that it has not joined, the registration request is discarded. When the subscriber is subscribed, it is further confirmed whether or not the multicast group permits the multicast information registration from the mobile terminal, and when the confirmation does not permit, the registration request is similarly discarded. If the message ID is granted, the message ID is added to the multicast service control device 14 in a form that can identify the type of information requested to be transmitted and the device holding the information. The following is a flow of multicast information distribution when the information to be distributed in the entire service area is the same and the information that is actually distributed is registered in a different multicast group for each base station area. (A) The mobile terminal sends a multicast information registration request for the self-added multicast group to the base station. The registration request includes its own terminal ID, multicast group ID, and information to be registered. (B) Upon receiving the registration request, the base station confirms the multicast group ID included in the registration request, and the type of information to be transmitted in the entire service area is the same, but the actually distributed information is different for each base station area. If it is a group, the terminal ID and the multicast group ID included in the registration request are assigned to the multicast base station data device A,
Inquiries are made to B and C, and it is confirmed whether or not the mobile terminal of the request transmission source has joined the multicast group. If the result of the confirmation is that it has not joined, the registration request is discarded. When the subscriber is subscribed, it is further confirmed whether or not the multicast group permits the multicast information registration from the mobile terminal, and when the confirmation does not permit, the registration request is similarly discarded. Message I, if allowed
In order to add D, the type of the information requested to be transmitted and the device holding the information are registered in the multicast base station data device 14 in a form that can be discriminated. By the above processing, the multicast information registration from the mobile terminal is realized for the two types of multicast information. The distribution of the registered multicast information is performed based on the above-mentioned multicast information distribution operation. The priority control of multicast communication is performed as follows. According to the present invention, by managing the multicast group joining information at two levels, that is, the entire service area level and the base station area level, the traffic for each multicast group or each mobile terminal can be predicted at two levels. In the present invention, a network resource calculation for priority control in multicast communication and a priority control device for determining the priority of information based on the calculation result are provided at each of two levels, and the above-mentioned two types of multicast information are provided. Realize effective priority control. The present invention does not depend on the priority control method, and the priority control management device 16
Alternatively, the priority setting method, the judgment logic, etc. used in the base station priority control devices A, B, C depend on the transmission method of the network and the design concept of the network, and are not particularly limited. As an example, FIG. 9 shows a case where exactly the same information is distributed in the entire service area. In this figure, the same components as those in FIG. 1 are designated by the same reference numerals. less than,
The flow of priority control of multicast communication when registering information to a multicast group to which the same information is distributed in the entire service area is shown. (A) In multicast information distribution, when the information requested to be transmitted is notified or registered by a transmission method with priority, the base station control device 12 that has read the information makes an inquiry to the priority control management device 16. . (B) Upon receipt of the inquiry, the priority control management device 16 inquires of the multicast service control device 14 about the number of subscriber terminals to the multicast group requested to be transmitted, and based on the obtained number of subscriber terminals, the priority of the network resource by multicast communication is changed. Calculate the load. Then, considering the obtained calculation result and the given priority, an appropriate priority is set and a response is returned to the base station controller 12. (C) The base station controller 12, which has received the priority response, sets the priority notified in the response to the multicast information in the transmission method and transmits a multicast information transmission request to each base station. (D) The base stations A, B, C that have received the multicast information transmission request by the transmission method with priority make an inquiry to the base station priority control devices A, B, C. (E) The base station priority control devices A, B, and C that have received the inquiry
The number of joining terminals in the own base station area to the requested multicast group is inquired to the multicast base station data devices A, B and C, and from the obtained number of joining terminals, the network resource in the own base station area by multicast communication is obtained. Calculate the load of. After that, considering the obtained calculation result and the given priority, the own base station areas A, B, C
To the base stations A, B, and C, and returns a response to the base stations A, B, and C. (F) The base stations A, B, and C that have received the priority response set the transmission method using the priority notified in the response to the multicast information, and transmit the multicast information to each mobile terminal by the multicast channel. . By the above processing, suitable priority control communication is realized in the dangerous multicast communication accompanied by explosive consumption of network resources. The movement of the mobile terminal between base station areas in this system is performed as follows. In the present invention, the base station areas A, B, and C are set so as to overlap each other so that the reception leakage area does not exist, and the location registration operation when the mobile host moves to the new base station area is performed by each radio. Based on the control method. In addition, by considering the distribution of multicast information to hosts existing in an area extending over a plurality of base station areas, it is not necessary to perform a process when the mobile terminal moves between base station areas. In addition, if the base station area is too large as the minimum management unit due to the nature of the information to be distributed by multicast communication, it may be possible to perform further segmentation within the base station area. At that time, there are two methods of partitioning: (a) defining a fixed partition and (b) dynamically defining an efficient partition depending on the distribution status of mobile terminals. In addition, when dynamically defining the divisions, as methods, (a) grasp the distribution status by the location registration information, (b) cause each mobile host to perform a test transmission on a multicast channel, and perform an interference wave on each mobile host. It is also possible to make changes such as analyzing the number of interfering terminals and grasping the distribution status by notifying the base station.

[0018]

According to the multicast communication function model of the present invention, the following effects can be obtained. While the conventional method does not necessarily include the registration of the multicast information from the mobile terminal, the present invention is a bidirectional information transmission type model that allows the registration of the multicast information from the mobile terminal. Information sharing is possible. Further, since the mobile terminal is provided only with the means for registering the multicast information and the actual information distribution is always performed from the base station controller, the multicast information management and the multicast information distribution control become easy. In the conventional method, a huge amount of information management is required because the information is distributed to the area where the user who requests the reception of the multicast information exists and the area near the user, and the distribution management is performed individually. On the other hand, in the present invention, a unique channel throughout the service area is defined as dedicated to multicast, and all mobile terminals can receive the information flowing through that channel. It is possible to perform multicast information distribution without increasing the number. In the conventional method, the multicast subscription information is centrally managed and held, whereas in the present invention, the multicast subscription information can be managed at two levels: the entire service area level and the base station area level. Therefore,
Even if a method is adopted in which all mobile terminals can receive information flowing through the multicast channel throughout the service area, unnecessary multicast communication is reduced, such as not performing multicast communication in the base station area where no subscriber terminal exists. It is possible. Further, in the conventional method, the priority control function is arranged only at the level of the entire service area, but in the present invention, the priority control device is provided at two levels of the level of the entire service area and the level of the base station area, and each level is provided. Calculates the load on network resources and sets appropriate priorities. Therefore, it is possible to avoid explosive use of network resources in a wired section or a wireless section during multicast communication. Further, the present invention does not limit the logic regarding the priority setting. As another effect, whether or not the terminal is a terminal that transmits and receives multicast communication has been fixed in the past, but in the present invention, since the mobile terminal is provided with the multicast communication function On / Off setting function, it can be adapted to the situation. It is possible to dynamically avoid unnecessary reception of multicast information. Further, according to the conventional technology, an IGMP (Internet G) in TCP / IP, which is generally highly implemented, is used.
group Management Protocol)
While not aware of the consistency and commonality with the logic of
In the present invention, the processing of managing the multicast group information is made common to the logic of managing the multicast group of IGMP. Therefore, when the wireless multicast network according to the present invention is connected to the TCP / IP wired multicast network. Also, the multicast group information management can be easily shared. Conventionally, it is assumed that only registered terminals will receive by specifying a multicast group.
In the present invention, encoding (encryption) using a group key is performed for each multicast group for both information reception and information registration. Therefore, even if a method is adopted in which all mobile terminals can receive the information flowing through the multicast channel throughout the service area, it is possible to avoid the information leakage. In the conventional method, the area individual information has to be registered in a plurality of multicast groups for each area, but in the present invention, the multicast subscription information is managed at two levels of the service area overall level and the base station area level, and the service is provided. Service area common information is managed at the entire area level, and area individual information is managed at the base station area level. Therefore, even in the area individual information, if the information types are the same, the information can be delivered only by one group registration. For example, if you want to get the nearest store information at the destination, if you have registered in the multicast group defined as "Distribute the nearest store information", each base station that receives a transmission request from the base station controller Reads and distributes its own base station area information to the multicast group, the current base station area information can always be obtained even if the base station area is moved. In addition, the message ID at the time of multicast information distribution is different from the service area common information in the case of area individual information distribution by using a base station control device or several different systems between base stations, and extends over multiple base station areas. Mobile terminals existing in the area can receive information from multiple base station areas.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a basic configuration model of a bidirectional information transmission type multicast communication system of a mobile terminal according to the present invention.

FIG. 2 is a model explanatory diagram of multicast group management and group registration of the multicast communication system according to the present invention.

FIG. 3 is a model explanatory diagram of multicast group management and group key distribution in the multicast communication system according to the present invention.

FIG. 4 is a model explanatory view of multicast communication and information common to all areas (group 1) of the multicast communication system according to the present invention.

FIG. 5 is a model explanatory view of multicast communication and information common to all areas (group 3) of the multicast communication system according to the present invention.

FIG. 6 is a model explanatory diagram of multicast communication and area individual information distribution (group 4) of the multicast communication system according to the present invention.

FIG. 7 is a model explanatory view of multicast communication and all area common information registration (group 1) of the multicast communication system according to the present invention.

FIG. 8 is a model explanatory diagram of multicast communication and area individual information registration (group 4) of the multicast communication system according to the present invention.

FIG. 9 is a model explanatory diagram of multicast communication of the multicast communication system according to the present invention, and information distribution (group 1) by priority control of information common to all areas.

[Explanation of symbols]

10 Base station control stage 12 Base station controller 14 Multicast service controller 16 Priority control management device 20 base stations 30 mobile terminals

Claims (7)

[Claims] 1. A plurality of base stations capable of bidirectional information transmission to and from mobile terminals belonging to respective service areas, a base station control device for collectively managing the plurality of base stations, and the plurality of base stations. A mobile terminal group capable of arbitrarily moving in the service area of any one or a plurality of base stations and capable of bidirectional information transmission, and an information decryption key for transmitting / receiving multicast information to / from each base station. Bidirectional information characterized by reducing the number of channels and unnecessary traffic as much as possible by making a multicast channel into a single channel that uses a common frequency and code in the entire service area. Originating multicast communication system. 2. The mobile terminal belonging to a two-way information transmission type multicast communication system is capable of requesting registration of multicast information only to a self-subscribed multicast group using the information decryption key. 1. The bidirectional information transmission type multicast communication system according to 1. 3. The base station control device controls each base station, reduces unnecessary multicast communication traffic, and enables network resource calculation and flexible operation for priority control service at each level. The two-way information transmission type multicast communication system according to claim 1 or 2. 4. A multicast communication system comprising a base station and a group of mobile terminals, which is a bidirectional information transmission type, wherein desired multicast data can be acquired by a request issued from the mobile terminal side to the base station. ,
A method of operating a bidirectional information transmission type multicast communication system, characterized in that the number of channels for multicast communication in the wireless section can be reduced as much as possible, wasteful traffic can be reduced as much as possible, and priority control of multicast communication can be performed. 5. Each mobile terminal has a key for decrypting the multicast information of its own multicast group, a terminal without this key discards the received multicast communication information, and each mobile terminal having this key 5. The method for operating a bidirectional information transmission type multicast communication system according to claim 4, wherein registration of the multicast information can be requested only to the self-joined multicast group. 6. A channel for multicast communication by defining a multicast channel as a single channel that uses a common frequency / code in the entire service area and performing transmission / reception of information related to multicast by using this multicast channel as much as possible. The method of operating a bidirectional information transmission type multicast communication system according to claim 4 or 5, characterized in that the number is reduced. 7. An unnecessary multicast communication traffic is reduced by arranging a multicast data device and a priority control device at each of the base station level and the base station level, and for priority control service at each level. The method for operating a bidirectional information transmission type multicast communication system according to any one of claims 4 to 6, wherein the network resource calculation and the flexible operation are possible.