1. Field of the Invention
The present invention relates to a communication system, a radio communication terminal and a radio communication device, for setting up a communication link while carrying out an authentication processing, which are directed to the case of carrying out transmission/reception of information by a short range radio communication such as Bluetooth between the radio communication terminal and the radio communication device, for example.
2. Description of the Related Art
Recently, the short range radio communication scheme having a transmission range of about 10 m has been attracting much attention. In contrast to the conventional radio LAN which has an effective transmission range of over 100 m, the short range radio communication scheme requires a smaller power consumption because of the short transmission range, so that it is suitable for an information processing device with a limited battery capacity such as a portable telephone.
The Bluetooth is one such short range radio communication scheme, and the portable information processing device (referred hereafter simply as a portable terminal) such as a portable telephone, a PDA, etc., which is equipped with a communication function according to this Bluetooth has been gaining increasingly popularity in recent years. For further details of the Bluetooth, the detailed specification can be obtained from the Web site “http://www.bluetooth.org/”.
When the Bluetooth becomes widespread, it becomes possible to provide a service suitable for each location, at any location. For example, at the convenience store, supermarket or retail store, it is possible to realize services for the benefit of purchasers such as an electronic coupon service, an electronic point service, an electronic payment, an electronic receipt, an electronic acknowledgement issuance, etc. Furthermore, applications to a gate controlling using an electronic ticket, payment and discount at the automatic vending machine, an information delivery, a road guidance, etc. are expected.
In the following, an exemplary case where a connection according to the Bluetooth is set up between a portable terminal equipped with the communication function according to the Bluetooth (hereafter simply referred to as a Bluetooth portable terminal) and an information communication device equipped with the Bluetooth (hereafter referred to as a Bluetooth device), and the Bluetooth device provides a service to a user who owns the portable terminal will be described.
The Bluetooth uses a frequency band that is open to public for commercial use, so that it can be easily obstructed by other devices using the same frequency band. For this reason, the Bluetooth employs the frequency hopping technique for periodically changing the utilized frequency so as to be less vulnerable to the obstruction from the other devices. In the frequency hopping, there is a need for an initial operation to establish synchronization between two devices for carrying out communications.
At a time of searching the other Bluetooth devices existing in its communication area, the portable terminal uses the Bluetooth device search function to sequentially scan through the predetermined frequency band and discover the Bluetooth devices that are standing by in an accessible state.
The Bluetooth device in the accessible state that received a search signal transmits a clock information along with its own terminal identification information to a search signal sender. The Bluetooth device in the accessible state is also periodically changing the utilized frequency, so that it takes several seconds before the frequencies coincide. Even under the ideal condition of having no radio communication device using the same frequency in a vicinity, it may take five seconds or more to discover one terminal depending on the circumstance. In the case where the device using the same frequency exists in a vicinity, it can possibly take even longer time.
The portable terminal collects a terminal identification information in 48 bits from each one of the discovered Bluetooth devices, and carries out the synchronization of the frequency hopping pattern with a desired (selected) Bluetooth device at a connection phase by using the clock information and 28 bits out of the terminal identification information of that Bluetooth device. After the hopping pattern is synchronized, a physical link is established, and thereafter layers are connected so that the exchange and setting of necessary parameters are carried out, and then it becomes possible to carry out the data exchange at the application level. The mutual authentication is carried out if necessary, and when the connection at the application level is established, the Bluetooth device provides a prescribed service.
In general, in comparison with the communication utilizing infrared rays, the radio communication has an advantage in that it is not affected by the positional relationship or obstacles between two devices, but it also has a property that it is difficult to set up a connection only with a terminal existing at a specific location.
This fact gives rise to the following problems. In the following, an exemplary case where a user who has the electronic coupon in the portable terminal uses that electronic coupon by carrying out communications with a cash register equipped with the Bluetooth communication function at a time of payment at a cash register of the convenience store will be considered.
In the case where only one customer (only one portable terminal) and only one cash register (only one Bluetooth device) are present, the relationship between the portable terminal of the customer who makes the payment and the cash register is uniquely determined so that no problem regarding the connection arises. In other wards, when a person who operates the portable terminal discovers the Bluetooth device by using the Bluetooth device search function described above, the discovered device can be regarded as the cash register to which the payment is to be made.
However, when a plurality of cash registers exist, the cash register of the next line will also be discovered, so that there is a need for the user who has the portable terminal to select the one cash register to which the payment is to be made from the discovered cash registers, by checking a name of the cash register or the like.
Also, in the case where the other customer waiting for his turn to make the payment also has a portable terminal, there is a possibility for the portable terminal of the other customer to make the connection with the cash register before the portable terminal of the customer currently in his turn to make the payment.
For this reason, there is a need for an operator of the cash register to check the customer if the connection is made with a right portable terminal or not, by using some information associated with the portable terminal.
Such selection and checking operations do not constitute a good interface for the customer who makes the payment and they also hinder the register operation of the operator.
Moreover, if the person operating the portable terminal specifies the wrong cash register, there can be troubles such as the amount to be paid is not discounted despite of the use of the coupon, or the points granted to the one customer are actually added to the other customer. The cancellation operation must be carried out at both the portable terminal and the cash register, which requires considerable time and effort.
In addition, in the system using radio, anyone can be accessible to the radio communications, so that there can possibly be a problem related to business obstruction and privacy due to an attack from a malicious user such as setting up a link earlier than an innocent user to prevent the innocent user to make the connection, or pretending the cash register to secretly acquire the personal information or steal coupons, etc.
Thus, conventionally, it has been difficult to establish one-to-one correspondence between the portable terminal and the Bluetooth device correctly, easily and quickly, by using the short range radio communications.