JPH0793666B2 - Billing terminal - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a charging terminal, and more particularly to a mobile communication system that includes a plurality of base stations connected to a public telephone network and provides a pay call service to a mobile terminal. Mobile charging terminals such as personal telephones.

[Conventional technology]

In the conventional fixed type or semi-fixed type telephone system, since the billing device was installed on the call route, it was easy to bill the call charge. However, in the mobile telephone system such as a personal telephone, such a billing process is performed. It was difficult to charge by the device.

[Problems to be solved by the invention]

In the above-mentioned conventional billing method, the call route between the center that holds the billing information for each telephone and the mobile telephone that can move throughout the country may be very different. There is a problem that not only the amount of communication increases but also the connection route becomes complicated.

[Means for solving problems]

According to the present invention, in a mobile communication system which includes a plurality of base stations connected to a public telephone network and provides a pay call service to a mobile terminal, an encryption code shared in advance with the base station is used. A storage unit that stores a key and a cumulative amount of charges for the call service that has already been received and an upper limit of the cumulative amount, and an identifier that identifies a connection request for receiving the provision of the call service with the base station. Identifier conversion means for converting based on a rule shared in advance between the base station, the base station and the encrypted amount and the encrypted identifier of the charge of the call service to be provided by the call service provider. Decryption means for receiving the data from the decryption means for decrypting using the encryption key, and using the encryption key for the conversion result obtained by the conversion means for the decrypted identifier. Encrypting means for encrypting, transmitting means for transmitting the result of this encryption to the base station, disconnecting means for disconnecting communication with the base station when receiving a disconnection command from the base station, and the call. Adding means for adding the decrypted call service charge amount to the accumulated amount when the service is received, and forced termination means for forcibly ending the provided call service when the accumulated amount exceeds the upper limit amount. It is possible to obtain a charging terminal characterized by including.

[Action]

FIG. 2 is a diagram showing the operation and principle of the present invention, and FIG. 3 is a block diagram of a system showing an application example of the present invention. Hereinafter, the terminal is a personal phone carried by an individual, and the service is a call. In addition, in FIG. 3, a base station (hereinafter referred to as BS) and a personal telephone (hereinafter referred to as PT)
Communication between them is wireless communication, and a system using a public line network is illustrated as an example, but the communication is not limited to this.

In FIG. 2, 201 and 202 show the processes related to charging on the PT side and BS side, respectively.

When PT makes a connection request, BS generates a random number (hereinafter referred to as RN) and encrypts it with a secret key K that is set in advance together with a call charge per unit time (hereinafter referred to as RT) (hereinafter referred to as E _K ). Note) Send E _K (RN, RT) to PT. In PT, this is decrypted with the key K to obtain RN and RT, and the data in which some bits of the predetermined RN are inverted (hereinafter referred to as RN ₁ ) is encrypted with the key K again E _K (RN ₁ ) To BS.
BS decrypts this to obtain RN ₁ , and if correct RN ₁ is not output, that is, if RN ₁ is wrong, instruct PT to disconnect, P
At T, the connection request is disconnected. Also, if the correct RN ₁ comes out on the BS, it connects and the call with the PT starts. PT remembers the total amount of telephone charges for this month (hereinafter referred to as CH) and the guarantee amount (hereinafter referred to as CR), but adds RT to CH at each unit time when a call is started. Then, when CH> CR or when the call ends, the connection with BS is disconnected and BS
Will also be restored.

Here, the CR deposit is a deposit to the service provider when the subscriber subscribes, and is applied when the telephone charge is not paid.

In FIG. 3, each PT is connected to the nearest BS, but if all BSs have the secret key K, it is possible to charge to any BS. Also,
There is no need to contact the subscriber information center for each call.
Therefore, the problems of the conventional method can be solved. In this case, PT
Is configured so that CH, CR, and K cannot be accessed even by subscribers.

〔Example〕

Next, the present invention will be described with reference to FIGS. 1 and 4.

FIG. 1 is a block diagram showing an embodiment of the present invention, and FIG. 4 is a flowchart showing the work executed by the microprocessor in FIG.

In FIG. 1, a voice circuit 4 converts voice and electric signals, and a billing circuit 6 performs billing processing such as generation of billing information. Further, the control circuit 5 generates or receives control information such as call setting and performs predetermined control, and also disconnects a call at the request of the charging circuit 6. The demultiplexing / demultiplexing circuit 3 multiplexes the control information from the control circuit 5 and the audio signal from the audio circuit 4 and sends it to the transceiver 2, or conversely demultiplexes the signal from the transceiver 2 to the audio circuit 4 and the control circuit 5. Send to.
The antenna 1 receives the radio wave from the BS and sends it to the transceiver 2, and conversely sends the signal from the transceiver 2 on the radio wave and sends it to the BS.

The billing circuit 6 has an interface circuit 61 that interfaces with the control circuit 5, an encryption / decryption circuit 64 that performs encryption and decryption with the key K, control of the interface circuit 61 and the encryption / decryption circuit 64, and data to the memory 62. And a memory 62 including a work area in addition to a storage area for programs and keys K for executing the flowchart shown in FIG.

It is desirable to make the charging circuit 6 into one chip so that even a subscriber or a PT user cannot access the inside. It is necessary to write the terminal number, key K or CH, etc. in this chip. For this, for example, there is a method of mounting the chip written in the subscriber information center at the time of subscription, and it is also possible to use an IC card. For payment at the end of the month, send the CH to the subscriber information center instead of the BS, and this subscriber information center may debit the bank.

Next, the work executed by the microprocessor 63 will be described with reference to FIG. When the PT calls and issues a connection request, the microprocessor 63 encrypts RN and RT with E _K (R
(N, RT) waiting for reception. When E _K (RN, RT) is received, it is decrypted, part of RN is bit-inverted, and key K
It will be encrypted and sent back and wait for the call connection. Once connected, billing starts and RT is added to CH each time a unit of time elapses.
CH> CR or end of call or disconnect request by BS to disconnect and end.

In this embodiment, encryption / decryption can be performed by the microprocessor. For CH, PT can store the balance (hereinafter referred to as CS) for CR instead of CH, and CS can be reduced when calling. Key K
Is less secure when used for a long time, so it is advisable to change it from time to time. The key to be used in the future can be set in advance and stored. It is also possible to divide all PTs into several groups, define a key for each group (denoted as a group key), and store all group keys in the BS to use as necessary.

RN and RN ₁ are used not only for tampering and error detection, but also for preventing unauthorized retransmission. Unauthorized retransmission is a method of storing a previous message and sending it later. It is possible to prevent these without using random numbers. For example, in Figure 2,
, The BS simply uses the time information (hereinafter referred to as TM) and sends E _K (TM, RT) instead of E _K (RN, RT), and PT decrypts it and TM If the time is close to that time, it can be determined that there is no injustice. Also, when there is a dishonesty
Notify the BS to prevent the connection.

In this embodiment, the key K is always used as the encryption / decryption key, but RN may be used as the key. In this case, when the RN is first sent from the BS to the PT, it is encrypted with the key K, but the subsequent encryption uses the RN, and falsification and error detection can be realized by providing information with redundancy. That is,
If the redundancy does not occur correctly when decrypted on the receiving side, it is determined to be fraudulent.

〔The invention's effect〕

INDUSTRIAL APPLICABILITY As described in detail above, the present invention is a mobile communication system that includes a plurality of base stations connected to a public telephone network and provides a pay call service to a mobile terminal, which is shared in advance with a base station. The base station has a storage means for storing the stored encryption key and a cumulative amount of charges for the already received call service and an upper limit of the accumulated amount, and an identifier for identifying a connection request for receiving the call service. Identifier conversion means for converting based on the rules shared in advance, and the encrypted amount and the encrypted identifier of the call service charge provided by the call service provider are received from the base station and encrypted. A decryption means for decrypting using the key, and an encryption means for encrypting the conversion result obtained by the conversion means for the decrypted identifier using the encryption key. Transmitting means for transmitting the result of this encryption to the base station, disconnecting means for disconnecting the communication with the base station when a disconnection command is received from the base station, and the total amount when the call service is received are decrypted. By providing addition means for adding the call service charge amount and forcible termination means for forcibly ending the call service being provided when the cumulative amount exceeds the upper limit, each mobile terminal, not the subscriber information center Since the billing process can be performed, there is a great effect that the billing can be performed with almost no increase in the process and communication amount on the network side.

[Brief description of drawings]

FIG. 1 is a block diagram showing an embodiment of the present invention, FIG. 2 is a diagram showing the operation and principle of the present invention, FIG. 3 is a block diagram of a system showing an application example of the present invention, and FIG. 3 is a flowchart showing the work executed by the microprocessor in FIG. 1. 1 ... Antenna, 2 ... Transceiver, 3 ... Multiplex / separation circuit, 4 ... Voice circuit, 5 ... Control circuit, 6 ... Billing circuit, 61 ... Interface circuit, 62 ... Memory, 63 ...
… Microprocessor, 64 …… Encryption / decryption circuit, 201,20
2 ... Processing related to billing on the PT side and BS side.

Claims (1)

[Claims] 1. In a mobile communication system which comprises a plurality of base stations connected to a public telephone network and provides a pay call service to mobile terminals, an encryption key shared in advance with the base station. And a storage means for storing the accumulated amount of charges for the call service already received and the upper limit of the accumulated amount, and an identifier for identifying a connection request for receiving the provision of the call service with the base station. From the base station, an identifier conversion unit for converting based on a rule shared in advance between the base station and an encrypted amount and an encrypted identifier of a call service charge to be provided by the call service provider. Decryption means for receiving and decrypting by using the encryption key, and a decryption result obtained by the conversion means for the decrypted identifier by using the encryption key. Encrypting means for encrypting, transmitting means for transmitting the result of this encryption to the base station, disconnecting means for disconnecting communication with the base station when a disconnection command is received from the base station, and the call service When receiving, the adding means for adding the decrypted call service charge amount to the accumulated amount, and the forced ending means for forcibly ending the provided call service when the accumulated amount exceeds the upper limit amount. A billing terminal, comprising: