JPH07203540A - Radio communication system - Google Patents

Abstract

PURPOSE:To provide a radio communication system capable of preventing the resources of a base station and radio resources from being unjustly used by an illegal radio mobile station. CONSTITUTION:A radio base station is provided with a means (25-1) holding network ID (1a third identification number) of the radio base station, a means (25-2) holding radio base station ID (a first identification number) and a means (25-3) preparing ciphering ID (a second identification number) from network ID and radio base station ID and holding it. This ciphering ID and ciphering ID, which is added to a signal transmitted from the radio mobile station and calculated by the radio mobile station, are compared and when they are not equal, the signal is not received.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wireless communication system composed of a wireless base station and a wireless mobile station, and in particular, the CPU resource of the wireless base station is illegally used by an unauthorized access from the wireless mobile station. The present invention relates to a wireless communication system capable of preventing the above.

[0002]

2. Description of the Related Art First, a conventional operation for making a call from a wireless mobile station to a wireless base station will be described. FIG. 9 is a diagram showing an example of a transmission sequence when a wireless mobile station transmits to a wireless base station. In the figure, reference numeral 91 denotes an upstream transmission signal from the wireless mobile station to the wireless base station, which is a signal for requesting establishment of a wireless link. An example of this upstream transmission signal is shown in FIG. In FIG. 10, 101 is a preamble for synchronizing in a wireless transceiver, 102 is an uplink synchronization word, 103 is a broadcast channel, dedicated control channel,
It is a channel type indicating a channel type such as an incoming channel, and is displayed as an individual control channel in an outgoing signal. 10
4 is the base station ID of the destination of the upstream signal, 105 is the mobile station ID of the wireless mobile station transmitting the outgoing signal, and 106 is the message type, in which case "outgoing" is displayed. 107
Is transmission signal data, and 108 is a CR for bit error detection
It is a C (Cyclic Redundancy Check) code.

Reference numeral 92 denotes a downlink channel designation signal from the radio base station, which is a signal for designating the channel of the radio link. FIG. 11 shows an example of this downlink channel designation signal. In FIG. 11, 111 is a preamble for synchronizing in a wireless transceiver, 112 is a downlink synchronization word, 113 is a channel type indicating a channel type such as a broadcast channel, an individual control channel, and an incoming channel, and individual control is performed with a channel designation signal. Displayed as channel. 11
4 is the base station ID of the radio base station transmitting the downlink signal,
115 is the mobile station ID of the wireless mobile station that is the destination of the downlink signal, and 116 is the message type, in which case "channel designation" is displayed. 117 is the data of the channel designation signal, and 118 is the CRC. Reference numeral 93 is a call setting signal for end-to-end call setting using a wireless link established by exchanging an upstream transmission signal 91 and a downstream signal 92, 94 is a call setting acceptance signal, and 95 is a wireless mobile station authentication. , 96 is an authentication response signal in response to the authentication request signal of 95. Reference numeral 97 indicates the timing of channel switching to the wireless link channel designated by the wireless base station.

Normally, the mobile radio station regularly receives an annunciation signal and an incoming signal from the radio base station, and when transmitting to the radio base station, it is displayed in the signal from the radio base station. As shown in FIG. 10, the base station ID 104 and the mobile station ID in the transmission signal are the base station ID and the mobile station ID which have been set.
It is displayed as 105. The wireless base station determines whether or not the base station ID 105 in the outgoing signal received from the mobile station is the same as the ID of its own base station, and recognizes that it is the outgoing signal to its own wireless base station only when the ID is the same. Also, when the radio base station transmits the channel designation signal to the radio mobile station, the radio base station displays its own radio base station ID and mobile station ID in the channel designation signal as the base station ID 114 and the mobile station ID 115 as shown in FIG. . As described above, the wireless mobile station can make a call to the wireless base station and receive the channel designation from the wireless base station. That is, in the transmission signal of FIG. 10 and the channel designation signal of FIG. 11, base station IDs 104 and 114, mobile station ID 1
Since 05 and 115 are the same, signals can be transmitted and received by both the wireless mobile station and the wireless base station. The radio base station starts the management of the radio mobile station and the radio resource management after specifying the channel. That is, for the wireless mobile station having the mobile station ID 105, CPU resources of the wireless base station,
Resources such as memory and radio will be allocated. In addition, a wireless link is established between the wireless mobile station and the wireless base station, and wireless resources are also allocated. The wireless base station side authenticates the wireless mobile station based on the authentication request 95 and the authentication response 96 to prevent unauthorized call connection of the wireless mobile station.

[0005]

In the conventional system as described above, when an unauthorized wireless mobile station exists, it is possible to prevent call connection of the unauthorized wireless mobile station by authentication. On the other hand, there is a disadvantage that the wireless base station resources such as the CPU and the wireless resources such as the wireless link are unnecessarily allocated. It is an object of the present invention to provide a wireless communication system that can solve the above-mentioned drawbacks and prevent unauthorized use of base station resources and wireless resources by wireless mobile stations.

[0006]

In order to achieve the above object, the present invention has means (25) for holding a third identification number for identifying a network of the radio base station in the radio base station (FIG. 2). -1), a means (25-2) for holding the first identification number for identifying the radio base station, and the encrypted second identification number from the exchange or calculated. Means, means for holding the obtained second identification number (25-3), means for periodically sending out a notification signal containing the third identification number, and sending out a signal containing the first identification number. And a means for receiving a signal having the second identification number, and means for receiving the third identification number by the notification signal from the wireless base station to the wireless mobile station (FIG. 4). A means (45-1) for storing the third identification number and a means for transmitting the identification number from the radio base station. And a means for receiving a signal having the first identification number, a means for calculating the encrypted second identification number, and a means for transmitting a signal including the second identification number calculated. It is characterized by that. The means for calculating the second identification number in the wireless base station and the wireless mobile station is calculated from the third identification number and the first identification number, or the third identification number is calculated.
The secret key corresponding to the identification number is previously stored (see FIG. 2).
25-1) of FIG. 4, 45-1) of FIG. 4, and means for obtaining by calculation from the secret key and the first identification number. Furthermore, the exchange (FIG. 3) is characterized by having means (35-1) for temporally changing the first identification number.

[0007]

The present invention uses the above first to third identification numbers,
Moreover, by keeping the means for calculating the second identification number from the third identification number and the first identification number secret, and by changing the calculation method for each third identification number,
It makes it impossible for an unauthorized wireless mobile station to cause the wireless base station to receive an outgoing signal. Even if the call is made by using the arbitrary second identification number, the wireless base station cannot receive the channel because it does not receive the call. Further, when the wireless base station receives a signal from a wireless mobile station, the conventional configuration receives a signal including its own wireless base station ID, whereas the configuration of the present invention uses the wireless base station ID Instead, only the signal including the encrypted identification number (second identification number) is received, and the signal processing amount does not increase at all regarding signal reception. Further, as a means for calculating the second identification number, a secret key corresponding to the third identification number is stored in advance, and a second key is obtained from the secret key and the first identification number.
By calculating the identification number of, the strength of the encryption can be further increased. Further, by providing a means for changing the identification number with time, it is possible to further prevent unauthorized access from an unauthorized wireless mobile station. With this configuration, the wireless base station can easily encrypt the identification number for wireless access transmitted from the wireless mobile station to the wireless base station without increasing the processing amount for signal reception. It is possible to eliminate wasteful allocation of radio base station resources and radio resources to mobile stations.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is a diagram showing an embodiment of a system configuration when the present invention is applied. In the figure, 11-a
And 11-b are radio base stations, 12-a and 12-b.
Are wireless zones of the wireless base stations 11-a and 11-b, 13 is an exchange station, 14 is a wireless mobile station, and 15 is a private line connecting the exchange station and the wireless base station. In the figure, the wireless zones of the wireless base stations 11-a and 11-b are assumed to be 12-a and 12-b, respectively. It is assumed that wireless mobile station 14 is in the overlapping portion of wireless zones 12-a and 12-b and is capable of receiving signals from both wireless base stations 41-a and 41-b. In this embodiment, the wireless base station 11
-A and 11-b, the wireless mobile station 14, the switching center 13, the notification signal that is periodically transmitted by the wireless base station, and the illegal wireless transfer by devising the uplink transmission signal from the wireless mobile station to the wireless base station. Prevents improper use of resources from the station. The configurations and operations of the wireless base station, the wireless mobile station, and the switching center in the embodiments of the present invention will be described in detail below.

First, the broadcast signal, upstream transmission signal, and downstream channel designation signal used in this embodiment will be described. From the wireless base station 11 to the wireless mobile station 1 in this embodiment
The downlink notification signal to 4 is configured as shown in FIG. 5, for example. In the figure, 51 is a preamble for synchronizing in a wireless transceiver, 52 is a downlink synchronization word, 53 is a channel type indicating the type of channel such as a broadcast channel, an individual control channel, an incoming channel, and 54 is the downlink signal. Of the radio base station 11-a which has transmitted
D and 55 are signals that indicate the type of message, and here, for example, indicate that the network ID is being notified. 56 is a network ID, 57 is data of a broadcast signal, and 58 is a code for bit error detection. It is assumed that the wireless base station 11 periodically transmits the notification signal of FIG. 5, for example.

Also, from the radio mobile station 14 to the radio base station 11
The upstream outgoing signal to -a is configured as shown in FIG. 6, for example. In the figure, 61 is a preamble for synchronizing in a wireless transceiver, 62 is a rising sync word, 63 is a channel type indicating the type of channel such as a broadcast channel, an individual control channel, an incoming channel, etc. Display as channel. 64 is the encryption I of the radio base station 11-a which is the destination of the rising signal.
D and 65 are wireless mobile stations 1 that are the senders of the rising signals.
The mobile station ID 4 and 66 are signals indicating the type of message, and here, for example, indicate that transmission is being performed. 67 is data of the transmission signal, and 68 is a CRC for bit error detection.

The downlink channel designation signal from the radio base station 11-a to the radio mobile station 14 is configured as shown in FIG. 7, for example. In the figure, 71 is a preamble for synchronizing in a wireless transceiver, 72 is a downlink synchronization word, 73 is a broadcast channel, an individual control channel,
A channel type indicating the type of channel such as an incoming channel is displayed as an individual control channel in the channel designation signal. 74 is the radio base station 11- which has transmitted the downlink signal.
a is the base station ID of a, 75 is the mobile station ID of the wireless mobile station 14 that is the destination of the signal, and 76 is a signal that indicates the type of message. Here, for example, it indicates that channel designation is being performed. . Reference numeral 77 is channel designation signal data, and 78 is a CRC code for bit error detection.

FIG. 2 is a diagram showing a configuration example of a radio base station in this embodiment, for example, the radio base station 11-a. In the figure, 21 is a wired interface device for connecting to the exchange 13 by wire, 22 is a wireless transceiver, and 2
Reference numeral 3 is a signal reception determination device for determining whether or not the signal received by the wireless transceiver 22 is addressed to the own wireless base station, and 24
Is a CPU (Central Processing Unit) that controls the entire wireless base station, and 25-1 to 25-6 are memories. When the wireless base station 11-a receives the transmission signal (FIG. 6) from the wireless mobile station 14, the CPU 24 causes the signal reception determination device 2
The encrypted ID calculated from the own wireless base station ID is set for 3. The signal reception determination device 23 monitors all the signals received by the wireless transceiver 22, and sends the signal to the CPU 24 when the encrypted ID 64 in the received signal matches the encrypted ID specified by the CPU 24. Work. For example, the wireless mobile station 14 is connected to the wireless base station 11-a.
When the signal is transmitted to the wireless base station 11-a, since the encrypted ID 64 is the encrypted ID corresponding to the wireless base station 11-a, only the wireless base station 11-a can receive it. Will never receive.

The memory 25 (25-1 to 25-6) is, for example, a memory as shown below. 25-1 is, for example, the network ID of the own base station (third identification number)
Is a memory for storing. In addition, network I
The secret key paired with D is also stored in this memory, and the third key
It corresponds to the private key corresponding to the identification number. As a method of setting the network ID and the secret key, for example,
A method is conceivable in which the same network ID and secret key are written from the exchange 13 to all the wireless base stations 11 (here, 11-a and 11-b) under the control when the system is started up. The network ID is displayed as a network ID 56 in a notification signal of FIG. 5 which will be described later, and indicates whether or not it is possible to connect to a wireless mobile station, and also specifies a method of calculating an encrypted ID. is there. 25-2 is a wireless base station ID (first identification number) indicating the ID of the wireless base station
Is a memory for storing. As a method of writing the present radio base station ID, for example, there is a method of writing from the exchange 13 as described later. Reference numeral 25-3 is a memory for storing an encrypted ID (second identification number) used when making a reception determination of a rising signal. As a method of storing this encrypted ID,
For example, the method of loading from the exchange 13 at the time of initial startup, and the encrypted program memory 25-5 described later
There is a method in which calculation is performed at the time of initial startup using the encryption program in and the result is stored. When receiving the upstream transmission signal shown in FIG. 6, the CPU 24 sets the main encrypted ID in the signal reception determination device 23 to perform signal reception.

Reference numeral 25-4 is a memory for storing the mobile station ID of the radio mobile station 14 currently controlled by the radio base station. This mobile station ID stores the mobile station ID in the signal as it is when the signal is received. When transmitting a downlink signal to the wireless mobile station 14 under control, this mobile station ID is displayed in the transmission signal (for example, mobile station ID 75 in FIG. 7). Reference numeral 25-5 is a memory for storing an encryption program for calculating the encryption ID at the initial startup. This memory is unnecessary when the calculation of the encrypted ID is not performed by the wireless base station. This encryption program has a one-to-one correspondence with a network ID, and as an example, it is assumed here that all the wireless base stations 11 (11-a, 11-b) under the control of the exchange 13 are the same. As a specific example of the encryption program using the secret key, for example, an algorithm based on the well-known encryption standard DES (Data Encryption Standard) standardized in the United States can be used.
Is used as the original text, the ciphertext is calculated by the DES algorithm using the secret key in the memory 25-1 as a key, and this ciphertext is used as the encrypted ID. Also, for example, the encrypted ID
As a simple method of obtaining, there is a method of taking the exclusive OR of the base station ID and the network ID. Reference numeral 25-6 is a memory that stores a control program for controlling the radio base station.

FIG. 3 is a diagram showing a configuration example of the exchange station 13 in this embodiment. In the figure, 31 is a switch circuit, 32 is a wireless base station interface for interfacing with the wireless base station 11, and 33 is a PSTN or ISDN.
Station line interface for connecting to public networks such as 3
4 is a CPU for controlling the exchange 13; 35 (35-1, 3;
5-2) is a memory. There are the following types of memory. Reference numeral 35-1 is a memory for storing a base station ID reset program for resetting the base station ID and the like. The identification number can be changed over time. An example of using this program will be described as an example of the method.
Here, it is assumed that the radio base stations 11 under the exchange 13 all have different numbers. In order to give a different number to the radio base station 11 and to change the number temporally, for example, a different number is given to each radio base station interface 62, an offset value is added to this number, and its modulo is added. Provide means to calculate. For example, once a day, the offset value is changed and designated to all the radio base stations 11. At the same time, all wireless base stations 11 are instructed to recalculate the encrypted ID. If the wireless base station 11 does not calculate the encrypted ID, a method of directly transmitting the encrypted ID from the exchange 13 to the wireless base station 11 is also conceivable. 35-2 is exchange 1
3 is a memory of a control program for controlling the whole.

FIG. 4 is a diagram showing a configuration example of the wireless mobile station 14 in this embodiment. In the figure, 41 is a handset, 42 is a wireless transceiver, 43 is a signal reception determination device for determining whether a signal received by the wireless transceiver 42 is addressed to the mobile station itself, and 44 is a wireless mobile station. A CPU for controlling the whole, 45 for a memory, and 46 for a dial key switch. When the wireless mobile station 14 receives the channel designation signal (FIG. 7) from the wireless base station, the CPU 44 sets the own mobile station ID in the signal reception determination device 43. The signal reception determination device 43 monitors all the signals received by the wireless transceiver 42, determines whether or not the mobile station ID 105 portion of the received signal matches the mobile station ID set by the CPU 44, and determines whether the signals match. Only when it does, it functions to send the received signal to the CPU 44. Furthermore, for example,
When receiving a signal from the wireless base station 11-a, the CPU
44 designates not only the mobile station ID to the signal reception determination device 43 but also the base station ID of the radio base station 11-a so as to receive only the signal addressed to the radio mobile station from the radio base station. To enable.

The memories 45 (45-1 to 45-4) are of the following types, for example. 45-1
Is a memory for storing the network ID (third identification number) of the receiving wireless base station 11. If the wireless mobile station 14 is a connectable wireless base station, the wireless mobile station 14 stores the network ID notified from the wireless base station in the memory 45-1. As a method for determining whether or not the wireless mobile station 14 can connect to the wireless base station, for example, all connectable network IDs are stored and collated with the network ID in the notification signal, and the matched signal is detected. There is a method to make it possible to connect only. The secret key and the encryption program paired with the network ID are stored in advance in this memory. When the wireless mobile station 14 stores a plurality of network IDs, the same number of private keys and encryption programs must be stored in advance. As a method of setting the network ID, the secret key, and the encryption program stored in advance, for example, a method of writing all network IDs, secret keys, and the encryption program that can be connected at the time of factory shipment can be considered. The encryption program can be realized by the same method as that described for the base station.

Reference numeral 45-2 is a memory for storing a radio base station ID (first identification number) indicating the ID of the radio base station 11. The wireless mobile station 14 stores the base station ID of the wireless base station 11-a to be connected in this memory. Wireless mobile station 14
When searching for a notification signal, for example, the signal reception determination device 43
The broadcast signal can be searched for by setting one of the broadcast channel as the channel type, the broadcast signal for the message, and the ID that the mobile station can receive for the network ID. For example, when the wireless mobile station 14 receives the notification signal of the wireless base station 11-a, the wireless mobile station 14 stores the base station ID 54 in the base station ID memory 45-2 and waits for a signal from the wireless base station. 45-3 is the mobile station ID of the wireless mobile station 14.
Is a memory for storing. As a setting method, for example,
A method of writing at the time of factory shipment is possible. 45-4
Is a memory that stores a control program for controlling the wireless mobile station 14.

FIG. 8 shows an example of transmission when the present invention is applied. Using the figure, the wireless mobile station 14 and the wireless base station 11
A transmission / reception operation performed between -a will be described. Wireless base station 1
The wireless mobile station 14 that originates a call to 1-a is, for example, the network ID of the wireless base station 11-a in the memory 45-1.
The encrypted ID is calculated from the base station ID in the base station ID memory 45-2 using the encryption program corresponding to.
Next, in order to transmit the transmission signal shown in FIG. 6, the individual control channel is used as the channel type 63, the encrypted ID calculated previously as the encrypted ID 64, and the mobile station ID 65 in the mobile station ID memory 65-3. Set the mobile station ID and make a call. Since the radio base station 11-a receives signals,
The encrypted ID memory 2 is previously stored in the signal reception determination device 23.
The encryption ID in 5-3 is set. In the signal reception determination device 23, the encrypted ID in the signal from the wireless mobile station 14
When 64 matches the set ID, the received signal is sent to the CPU 24. The CPU 24 is the signal reception determination device 2
The message type 66 and the data 67 are analyzed for the signal from No. 3, and the mobile station ID 65 is stored in the mobile station ID memory 25-4. Next, in order to send the channel designation signal shown in FIG.
, The individual control channel, the base station ID 74, the base station ID in the base station ID memory 45-2, and the mobile station ID 7.
5, the mobile station ID in the mobile station ID memory 45-3 is
The channel designation is set as the message type 76, the channel data designated as the data 107 is set, and the channel designation signal is transmitted. As described above, the legitimate transmission of the wireless mobile station 14 and the channel designation can be performed.

Next, the effectiveness of the present invention will be described by taking as an example the operation when a call is originated from an unauthorized wireless mobile station.
For example, in the memory 45-1 in the wireless mobile station, the wireless base station 1
From an unauthorized wireless mobile station that does not have the encryption program corresponding to the network ID 1-a to the wireless base station 11-
Consider a case where an unauthorized wireless mobile station makes a call to a. In this case, the encrypted ID cannot be calculated. In this case, for example, an individual control channel as the channel type 63, arbitrary data as the encryption ID 64, and a mobile station ID
It is assumed that the mobile station ID in the mobile station ID memory 45-3 is set as 65, and arbitrary data is masqueraded as an encrypted ID to transmit the transmission signal shown in FIG. Since the wireless base station 11-a receives the signal, the encrypted ID in the encrypted ID memory 25-3 is set in the signal reception determination device 23 in advance. The signal reception determination device 23 collates the encrypted ID 64 in the signal from the unauthorized wireless mobile station with the set ID, but if they do not match, the CPU 2
No signal is sent to 4. Therefore, the signal from the unauthorized mobile station is not received, and it is possible to prevent the base station resources and the wireless resources of the wireless base station 11-a from being wastefully used by the unauthorized wireless mobile station. Especially in the case of the second generation cordless telephone system (digital cordless telephone system), the method of the present embodiment is effective because it occupies a wideband control channel for wireless access until the mobile station is authenticated.

[0021]

According to the present invention, the radio base station can easily encrypt the number for radio access transmitted from the radio mobile station to the radio base station without increasing the processing amount for signal reception. As a result, it is possible to prevent the wireless base station resources and the wireless resources from being unnecessarily allocated to the unauthorized mobile station, and the resources can be effectively used.

[Brief description of drawings]

FIG. 1 is a diagram showing an example of a system configuration when the present invention is applied.

FIG. 2 is a diagram showing a configuration example of a radio base station according to an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration example of a switching center in an embodiment of the present invention.

FIG. 4 is a diagram showing a configuration example of a wireless mobile station according to an embodiment of the present invention.

FIG. 5 is a diagram showing a downlink notification signal from a wireless base station to a wireless mobile station according to an embodiment of the present invention.

FIG. 6 is a diagram showing an upstream transmission signal from a wireless mobile station to a wireless base station according to an embodiment of the present invention.

FIG. 7 is a diagram showing a downlink channel designation signal from a wireless base station to a wireless mobile station according to an embodiment of the present invention.

FIG. 8 is a diagram showing a transmission / reception sequence of a transmission signal and a channel designation signal between a wireless mobile station and a wireless base station according to the present invention.

FIG. 9 is a diagram showing a transmission sequence when a wireless mobile station in a conventional example transmits to a wireless base station.

FIG. 10 is a diagram showing an upstream transmission signal from a wireless mobile station to a wireless base station in a conventional example.

FIG. 11 is a diagram showing a downlink channel designation signal from a wireless base station to a wireless mobile station in a conventional example.

[Explanation of symbols]

 11-a, 11-b Wireless base station 12-a, 12-b Wireless zone 13 Switching station 14 Wireless mobile station 21 Wired interface device 22 Wireless transceiver 23, 43 Signal reception determination device 24, 34, 44 CPU 25, 35 , 45 memory 31 switch circuit 32 wireless base station interface 33 station line interface 41 handset 42 wireless transceiver 46 dial key switch

Claims (3)

[Claims] 1. A wireless communication system having a wireless base station, a wireless mobile station, and a switching center, wherein the wireless base station holds a third identification number for identifying a network of the wireless base station, and the wireless base station. Means for holding a first identification number for identifying a base station, means for receiving an encrypted second identification number from a switching center, or means for calculating, and holding the obtained second identification number Means, a means for periodically transmitting a notification signal including the third identification number, a means for transmitting a signal including the first identification number, and a signal including the second identification number. Means for receiving the third identification number by the notification signal from the wireless base station, and the third mobile station receiving the third identification number.
Means for storing the identification number, means for receiving a signal including the first identification number transmitted from the radio base station, means for calculating the encrypted second identification number, and means for calculating And a means for transmitting a signal including the obtained second identification number. 2. The radio communication system according to claim 1, wherein the means for calculating the second identification number in the radio base station and the radio mobile station is based on the third identification number and the first identification number. A wireless communication system, which is means for obtaining by calculation, or storing a secret key corresponding to a third identification number in advance, and obtaining by calculation from the secret key and the first identification number. 3. The wireless communication system according to claim 1 or 2, wherein the exchange has means for temporally changing the first identification number.