JPS5911211B2 - Confidential control method in mobile communication system - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to control of transmission of a code for a secret message in a communication channel and insertion of a secret message when a mobile device changes zones in a mobile communication system using a small zone configuration.

In the conventional car telephone system with a small zone configuration, confidential communication is not introduced.

On the other hand, in the large zone system, the inverted secret system is used in wireless systems for urban disaster countermeasures, ship telephones, and the like. In this case, since there is only one zone, the mobile device does not shift from zone to zone during a call, and there is no problem. Even in a small zone configuration, if the same type of confidential communication system is used for all communication channels, there is no need to transmit information such as the confidential communication code and presence/absence. However, when a confidential message is inserted according to the user's request, or when multiple confidential message keys are set for a call, it is necessary to continue a normal conversation when the mobile device moves from one zone to another. , it becomes necessary to send and receive confidential information between wireless base stations and between mobile devices and base stations, and some kind of countermeasure is required. Confidential communication means that during a call, the voice is scrambled and sent to prevent the contents of the call from being eavesdropped on, and unless a certain rule (key) is used on the receiving side, the scrambled voice cannot be transmitted. This means to make it irreversible. This invention was made in response to the above-mentioned countermeasures, and therefore, an object of the invention is to maintain a predetermined secret conversation even when a mobile device moves from one zone to another during communication. The purpose of the present invention is to provide a confidential communication control method in a mobile communication system that allows for communication.

The outline of the configuration of this invention is as follows.

In other words, a wireless base station located in each wireless zone,
A mobile station within a service area consisting of a radio network control station that controls and controls the radio base station, a mobile switching center that connects the radio network control station and the general telephone line network, and a set of each of the radio zones. A privacy control method in a mobile communication system in which the wireless network control station controls switching of the communication path between the mobile device and the wireless base station when the mobile device moves from zone to zone. When performing a confidential message for a channel, a confidential message request signal is sent from the mobile device to the wireless base station, and the mobile device and the wireless base station insert a previously specified confidential message, and the wireless base station sends the confidential message request signal to the radio network control station. The radio network control station stores the information in a channel compatible memory for channel switching, and when the mobile device shifts from zone to zone during a call, the radio network control station performs channel switching. This is a confidential message control method in a mobile communication system, which is characterized by transmitting information indicating the existence of a confidential message to a wireless base station in a transition destination zone together with the command, executing channel switching, and inserting a confidential message. Next, an embodiment of the present invention will be described with reference to the drawings.

FIG. 1 is a conceptual diagram of a mobile communication system having a small zone configuration.

In the figure, A, B, and I are radio base stations (MBS), respectively.
), 1, 2, and i are radio zones corresponding to radio base stations A, B, and I, respectively, D is a radio channel control station (MCS), and 4 is an inter-station link. Note that the radio line control station D is connected to the general telephone line via a car telephone switching center (mobile phone switching center) not shown, and is located within a service area consisting of a set of radio zones 1, 2, and 1. It is now possible to make a call between the mobile device (car) M and the general telephone line. When the mobile device M moves from one radio zone to another during a call, the radio network control station D controls the switching of the communication path between the L device and the radio base station. FIG. 2 shows a memory table for switching communication channels provided in the radio network control station D.

This table stores mobile device numbers, wireless zone numbers, channel numbers, and zone identification codes. This table is newly provided with a 1-bit memory for storing the presence or absence of confidential information. FIG. 3 is a flowchart of the control operation of the confidential conversation control method according to the present invention.

The operation will be described below with reference to FIGS. 1 to 3.

Assume that a mobile station (MSS) M starts a call in zone 1 and requests privacy. The privacy request signal is transmitted to the wireless base station A. The radio base station A informs the radio network control station (M
CS) Transmit to D. The radio network control station D stores information indicating the existence of a confidential conversation in the memory for switching the channel in use by the mobile device M. Next, mobile device M is in zone 1.
Assume that the zone has moved from the zone to the zone i. In this case, channel switching is controlled by the radio network control station D, and the radio base station (
MBS) I specifies an available communication channel, and mobile device M also switches the communication channel to the new channel. At this time,
The radio network control station D transmits the information to the radio base station 1 if the mobile device M uses a confidential message. From this point on, the mobile device M can continue the secret conversation. In the above method, in addition to the case where a secret method using the same key is used, it is also possible to use a secret method using different keys depending on the zone identification code.

In the current car telephone system, in order to avoid malfunctions due to co-channel interference, zone identification codes are provided to make the format of the call termination signal different when the same channel is used geographically apart. "Car Telephone Radio Line Control" Yoshikawa et al., Research and Practical Application Report, Telecommunications Research Institute of the Telephone and Telecommunications Corporation VOL, 26, Jff). 7). This identification code consists of 3 pits,
One of seven types is to be specified.

One zone identification code is assigned to each wireless base station. On the other hand, the zone identification code is also transmitted to the mobile device before starting a call. Therefore, if a secret key corresponding to the zone identification code is used, there is no need to newly transmit the key between the mobile device and the radio base station. When the mobile device moves from zone to zone, the zone identification code is transmitted together with the channel designation signal at the time of channel switching, so that information can be used.
Next, we will consider how to deal with the case where a secret message with a different key code is used for each call.

In this case, the mobile device attaches a code constituting the secret key to a secret request signal and transmits it to the radio base station. In response to channel switching, since information indicating the existence of a confidential conversation is transmitted from the radio network control station to the switching destination radio base station, the confidential conversation can be continued by sending a command to retransmit the confidential conversation request after channel switching. As explained above, according to the present invention, 1-bit information indicating whether or not a confidential conversation is present is stored in the communication channel switching memory provided in the radio network control station in a manner compatible with the communication mobile device. Confidential conversations can be continued even if the mobile device changes zones.

Furthermore, this method can handle not only one type of key code but also seven types of confidential keys corresponding to the number of zone identification codes. Furthermore, since only 1 bit of additional memory is required, the cost is low.

[Brief explanation of drawings]

Fig. 1 is a conceptual diagram of the configuration of a mobile communication system with a small zone configuration, Fig. 2 is a conceptual diagram showing a memory table for switching communication channels provided in a radio network control station, and Fig. 3 is a secret story according to the present invention. This is a flowchart of the control operation of the control method. Code explanation, 1, 2, i... Wireless zone, 4...
...Inter-office line, A, B, I...Radio base station, D...Radio line control station.

Claims (1)

[Claims] 1. A radio base station located in each radio zone, a radio network control station that controls and controls the radio base station, a mobile switching center that connects the radio network control station to the general telephone network, and each of the above-mentioned radio base stations. When a mobile device moves from zone to zone, the wireless network control station controls the switching of the communication path between the mobile device and the wireless base station. This is a confidential message control method in a mobile communication system carried out by a mobile phone, and when performing confidential communication on a communication channel, a confidential message request signal is sent from the mobile device to the wireless base station, and the mobile device and the wireless base station insert a confidential message specified in advance. Then, the radio base station transmits confidential information to a radio network controller, and the radio network controller stores the information in a channel corresponding memory for channel switching, and when the mobile device leaves the zone during a call. When moving to a zone, the radio network control station transmits a channel switching command as well as information indicating that a secret message exists to the radio base station of the destination zone, executes channel switching, and inserts a secret message. Confidential control method in mobile communication system.