Communication system, communication apparatus and method for setting communication parameters of the apparatus

A wireless terminal which newly joins a wireless communication system transmits a message containing its identification data to an access point in the wireless communication system at a communication parameter setting start. Upon receiving the message, the access point determines whether or not the wireless terminal has been registered. If it is determined that the wireless terminal has not been registered, the access point determines whether or not the wireless terminal is a setting target device of communication parameters based on the identification data contained in the message. If it is determined that the wireless terminal is a setting target device, the access point sets communication parameters for the wireless terminal.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a communication system, communication apparatus and method for setting communication parameters.

2. Description of the Related Art

To conduct communication via wireless LAN, it is necessary to set wireless LAN communication parameters (such as a network identifier called an SSID (Service Set ID), encryption key, authentication method and authentication key) among devices which conduct communications. Techniques have been proposed for simplifying the setting of communication parameters, which has been troublesome for users. For example, a method for setting communication parameters to be used between an access point and a station by transferring the parameters automatically from the access point to the station has been implemented into a product.

Also, Japanese Patent Laid-Open No. 2003-218875 (reference 2) describes a technique in which communication parameters are transmitted after being encrypted by an encryption method (WEP or common key, and devices which receive the communication parameters decrypt and set the parameters.

With the communication parameter setting methods described in references 1 and 2, when setting communication parameters for a device in operation (in communication), the operation must be stopped once before setting the communication parameters in order to specify the setting target device and to prevent leakage of the communication parameters.

In contrast, Japanese Patent Laid-Open No. 2003-338821 discloses a method for setting communication parameters without stopping the operation of a device in operation. This method uses default communication parameters to set operating communication parameters for a terminal which newly joins a network.

The conventional technique described above uses the default communication parameters for communication parameter transfer. Consequently, the transmitted communication parameters may be intercepted by malicious third parties (devices). Also, during communication parameter setting, operating communication parameters are switched to the default communication parameters, making it necessary for the communicating devices to perform the switching.

SUMMARY OF THE INVENTION

The present invention has as an object to solve the problems with the conventional techniques described above.

It is a feature of the present invention to make it easier for communication devices which newly join a network to set communication parameters.

According to an aspect of the present invention there is provided a communication system comprising:

a first communication apparatus which newly joins the communication system; and

a second communication apparatus which has joined the communication system,

wherein the first communication apparatus comprising:

a transmission unit configured to transmit a message containing identification data of the first communication apparatus to the second communication apparatus, in response to a communication parameter setting start,

the second communication apparatus comprising:

a registration determination unit configured to determine whether or not the first communication apparatus which transmitted the message has been registered;

a determination unit configured to determine whether or not the first communication apparatus is a setting target device of communication parameters based on the identification data contained in the message; and

a parameter setting unit configured to set communication parameters for the first communication apparatus based on the determination made by the registration determination unit and the determination made by the determination unit.

According to an aspect of the present invention there is provided a method for setting communication parameters among a plurality of communication apparatus, comprising:

a transmission step of transmitting a message containing identification data of a first communication apparatus to a second communication apparatus in response to a communication parameter setting start on the first communication apparatus;

a registration determination step of determining on the second communication apparatus whether or not the first communication apparatus which transmitted the message has been registered;

a determination step of determining whether or not the first communication apparatus is a setting target device of communication parameters based on the identification data contained in the message; and

a parameter setting step of setting communication parameters for the first communication apparatus based on the determination made in the registration determination step and the determination made in the determination step.

DESCRIPTION OF THE EMBODIMENTS

Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. It should be noted that the embodiments below do not limit the present invention set forth in the claims and that not all of the combinations of features described in the embodiments are necessarily essential as means for attaining the objects of the invention.

First Embodiment

FIG. 1is a schematic diagram of a wireless communication system according to a first embodiment of the present invention.

The wireless communication system includes an access point104, wireless terminal101, and wireless terminal107which conduct wireless LAN communication compliant with IEEE 802.11. The access point104is equipped with a wireless communication unit105and included in a wireless LAN. A button106is used to give a command to start automatic setting of communication parameters. When the button106is pressed, the access point104starts automatic setting of the communication parameters. The wireless terminal101is equipped with a wireless communication unit102. When a button103is pressed, the wireless terminal101starts an auto-setting process of communication parameters. Similarly, the wireless terminal107is equipped with a wireless communication unit108and when a button109is pressed, the wireless terminal107starts an auto-setting process of communication parameters.

Here, the access point104forms a first wireless network110using first communication parameters111. Also, the wireless terminal107is communicating with the access point104by setting the first communication parameters111. That is, the access point104decides that the wireless terminal107has been registered with the first wireless network110.

On the other hand, the wireless terminal101is a newly joining terminal of the first wireless network110. That is, the access point104decides that the wireless terminal101has not been registered with the first wireless network110. The access point104and wireless terminal101has an encryption key for registration as a secret key and a public key, respectively.

FIG. 2is a block diagram showing a configuration of the wireless terminal101according to the first embodiment.

A controller (CPU)201controls overall operation of the wireless terminal101. A wireless communication processor202controls communication with the wireless LAN. A power supply unit203supplies electric power to the wireless terminal101. A RAM204is used to temporarily store various data. A ROM205stores programs (control instructions) executed by the controller201, various data, and the like. An antenna206and antenna controller207are components of the wireless communication unit102. The button103is used to start setting the communication parameters, i.e., it is used to start the auto-setting process of the communication parameters. A display unit209is a liquid crystal display or the like and is used to display operator messages and the like. A console unit210contains various keys and buttons and is operated by an operator. A communication interface (I/F)211is used for communication other than wireless communication. It may be, for example, a USB, IEEE 1394, or other interface. A real-time clock212keeps time and informs the controller201of the present time. A timer213measures the elapsed time after instructions are received from the controller201and when a specified time elapses, it informs the controller201using an interrupt or the like.

The wireless terminal107has the same configuration as the wireless terminal101, and thus a description thereof will be omitted.

FIG. 3is a block diagram showing a configuration of the access point104according to the first embodiment.

A controller301controls overall operation of the access point104. A wireless communication processor302controls communication via the wireless LAN. A power supply unit303supplies electric power to the access point104. A RAM304is used to temporarily store various data. A ROM305stores programs (control instructions) executed by the controller301, various data, and the like. The button106is used to start setting the communication parameters, i.e., it is used to start a communication parameter setting process. An antenna controller307and antenna308are components of the wireless communication unit105. A display unit309is a liquid crystal display or the like and is used to display operator messages and the like. A console unit310contains various keys and buttons and is operated by an operator. A communication interface (I/F)311is used for communication other than wireless communication. It may be, for example, a USB, IEEE 1394, or other interface. A real-time clock312keeps time and informs the controller301of the present time. A timer313measures the elapsed time after instructions are received from the controller301, and when a specified time elapses, it informs the controller301using an interrupt or the like. A registration manager314stores and manages information about devices registered with the access point104.

The wireless terminals and access points according to the other embodiments described below have the same configurations as those shown inFIGS. 2 and 3.

FIG. 4is a diagram illustrating a concrete example of the first communication parameters111according to the first embodiment. In the first communication parameters111, an SSID (Service Set ID) serving as a network identifier is “ABC”. WEP (Wired Equivalent Privacy) is used as an encryption scheme. As an encryption key, “zxfgmtqlc” is used. Its key length is 128 bits. As an authentication method, Open authentication is used.

According to the first embodiment, the access point104, wireless terminal101, and wireless terminal107keep time (in absolute time) using their own real-time clocks. According to the first embodiment, the absolute time at which communication parameters are started to be set are used as identification data to identify the setting target device. If values of the identification data match or are within a predetermined tolerance, it is considered that validation of the target device has been successful. That is, the wireless terminal101and access point104start setting the communication parameters simultaneously to make it possible to identify the setting target device of the communication parameters.

Next, a description will be given of a method for setting the communication parameters according to the first embodiment. According to the first embodiment, the access point104is communicating with the wireless terminal107using an encryption key (included in the first communication parameters111) for communication. It periodically transmits a beacon containing SSID=ABC as the SSID of the wireless network110. The beacon also contains, as a time stamp, the time at which it is transmitted.

A flow of this embodiment will be described below.

FIG. 5is a flowchart explaining a beacon reception process on the wireless terminal101according to the first embodiment. A program which performs this process is stored in the ROM205and is executed under the control of the controller201.

The access point104transmits a beacon1101(FIG. 11) which contains, as a time stamp, the time given by the real-time clock312. The wireless terminal101receives the beacon1101from the access point104in Step S501and adjusts its real-time clock212in Step S502based on the time stamp contained in the beacon1101. This makes it possible to synchronize the real-time clock312of the access point104with the real-time clock212of the wireless terminal101.

FIGS. 6 and 7are flowcharts explaining a communication parameter setting process on the wireless terminal101according to the first embodiment. A program which performs this process is stored in the ROM205and is executed under the control of the controller201.

FIG. 8is a flowchart explaining a communication parameter setting process on the access point104according to the first embodiment. A program which performs this process is stored in the ROM305and is executed under the control of the controller301.

FIGS. 9 and 10are flowcharts explaining part of a frame reception process in a determination process on the access point104shown inFIG. 8.

FIG. 11is a diagram explaining a communication parameter setting sequence performed between the wireless terminal101and access point104according to the first embodiment.

The processes according to this embodiment will be described below with reference to these drawings.

To start setting communication parameters, a user of the wireless terminal101presses the button103, thereby giving a command to start the communication parameter setting. Consequently, in Step S601, the wireless terminal101reads the time at which the button103is pressed from the real-time clock212and stores it in the RAM204as setting identification data of the wireless terminal101. In Step S602, the wireless terminal101starts scanning a beacon. Incidentally, as shown inFIG. 11, the wireless terminal101has already received the beacon from the access point104when the button103is pressed. That is, the real-time clock312of the access point104and real-time clock212of the wireless terminal101are in synchronization.

The flowchart inFIG. 8is started when the user of the access point104presses the button106, thereby giving a command to start setting communication parameters. Consequently, in Step S801, the access point104reads the time at which the button106is pressed from the real-time clock312and stores it in the RAM304as setting identification data for the access point104.

In Step S602inFIG. 6, if the wireless terminal101receives a beacon1101(FIG. 11) from the access point104, it detects “SSID=ABC” contained in the beacon. After the detection of the SSID, the wireless terminal101performs a management/control frame transmission process in Step S603. This process is compliant with IEEE 802.11. In this process, for example, a probe request is transmitted.

FIG. 7is a flowchart explaining the probe request transmission process.

According to the first embodiment, a probe request1102is transmitted in Step S611. The probe request containing the detected “SSID=ABC” is transmitted to the access point104.

Upon receiving the probe request1102(FIG.11) from the wireless terminal101, the access point104decides in Step S802(FIG. 8) that a message has been received and determines in Step S803whether the message is a data frame. Since the probe request1102is a control frame, the process of the access point104advances to Step S805to perform a frame reception process for a frame other than a data frame.

The frame reception process is performed according to procedures for processing a management/control frame and is compliant with IEEE 802.11 (FIGS. 9 and 10).

This process includes a probing process, which is performed based on the received probe request1102.

FIG. 9is a flowchart explaining the probing process.

After receiving the probe request in Step S901, the process of the access point104advances to Step S902. In Step S902, the access point104compares the SSID contained in the received probe request1102with the “SSID=ABC” of the first wireless network110constructed by the access point104. If it is found as a result of the comparison that the SSID is correct (matches), the process advances to Step S903to transmit a probe response1103to the wireless terminal101. On the other hand, if it is found in Step S902that the SSID is not correct (does not match), the process advances to Step S904, where the access point104discards the frame and finishes processing.

After receiving the probe response1103in Step S612inFIG. 7, the process of the wireless terminal101advances to Step S604(FIG. 6) to establish a wireless link with the access point104and transmit an association request1104containing an SSID to the access point104.

Upon receiving the association request1104from the wireless terminal101, the access point104decides in Step S802(FIG. 8) that a message has been received and determines in Step S803whether the message is a data frame. Since the association request1104is a control frame, the process of the access point104advances to Step S805to perform a frame reception process for a frame other than a data frame.

This process includes an association process, which is performed to process the received association request1104.

FIG. 10is a flowchart explaining the association process.

Upon receiving the association request1104in Step S905, the process of the access point104advances to Step S906. In Step S906, the access point104compares the SSID contained in the received association request1104with the “SSID=ABC” of the first wireless network110constructed by the access point104. If it is found as a result of the comparison that the SSID is correct (matches), the process of the access point104advances to Step S907to transmit an association request1104to the wireless terminal101. On the other hand, if it is found in Step S906that the SSID is not correct (does not match), the process advances to Step S908, where it discards the frame and finishes processing.

Consequently, the wireless terminal101receives an association response1105in Step S605inFIG. 6. Thus, a wireless link has been established between the wireless terminal101and access point104.

Upon receiving the association response1105(FIG. 11), the wireless terminal101transmits a registration request message1106containing its setting identification data (start time) to the access point104. The registration request message1106is encrypted with an encryption key (public key) for a registration request in Step S606(FIG. 6) and transmitted to the access point104in Step S607.

Consequently, the access point104receives the registration request message1106from the wireless terminal101. As a result, the wireless terminal101decides in Step S802(FIG. 8) that a message has been received. In Step S803, it determines whether the message is a data frame. Since the registration request message1106is a data frame, the process of the access point104advances to Step S804to determine whether the sender of the message is a device registered with the first wireless network110. The determination is made by the registration manager314. Specifically, it is determined whether the device has been registered with the registration manager314.

The wireless terminal101is not registered with the first wireless network110at the time when it transmits the registration request message1106(FIG. 11). Therefore, the access point104decides that the wireless terminal101is an unregistered device. Consequently, the process of the access point104advances from Step S804to Step S807and tries to decrypt the message received from the wireless terminal101judged to be an unregistered device with the encryption key (secret key) for a registration request. If the message cannot be decrypted with the encryption key for a registration request, the access point104decides that the message is invalid and the process advances to Step S814to cut off the wireless link.

On the other hand, if the message is decrypted successfully in Step S807, the process of the access point104advances to Step S808to determine whether the message is a registration request message1106. If it is found as a result of the determination that the message is not a registration request message1106, the process advances to Step S814, where it decides that the message is invalid and cuts off the wireless link. On the other hand, if it is found in Step S808that the message is a registration request message1106, the process of the access point104advances to Step S809to compare the setting identification data of the wireless terminal101contained in the registration request with the setting identification data possessed by the access point104. If it is found as a result of the comparison that values of the setting identification data match or are within a defined tolerance, it is considered that the device has been validated successfully. Consequently, the process of the access point104advances to Step S810to encrypt a registration acceptance message1107(FIG. 11) containing an encryption key for communication parameter setting with an encryption key (secret key) for a registration request. The access point104transmits the encrypted registration acceptance message1107to the wireless terminal101in Step S811. On the other hand, if validation of the device fails in Step S809, the process advances to Step S814and cuts off the wireless link.

According to the first embodiment, since the setting identification data is provided in the form of a setting start time, validation based on the setting identification data is considered to be successful if the difference between the setting start time of the access point104and setting start time of the wireless terminal101falls within a certain range such as five seconds (inclusive).

Upon receiving the registration acceptance message1107in Step S608(FIG. 6), the process of the wireless terminal101advances to Step S609to decrypt the registration acceptance message1107with the encryption key (public key) for a registration request. In Step S610, the wireless terminal101starts a communication parameter setting sequence1108(FIG. 11) together with the access point104using the encryption key for communication parameter setting contained in the registration acceptance message1107. The communication parameter setting sequence1108is also performed between the wireless terminal101and access point104in Step S812inFIG. 8. In the communication parameter setting sequence1108, the access point104encrypts the first communication parameters111with the encryption key for communication parameter setting and transmits it to the wireless terminal101. The wireless terminal101receives the first communication parameters111and decrypts the parameters with the encryption key for communication parameter setting to set in the wireless terminal101. When the communication parameter setting sequence1108is completed, in Step S813inFIG. 8, the access point104registers the wireless terminal101with the registration manager314as a device already registered with the first wireless network110. The wireless terminal101on which the communication parameters have been set can now conduct data communication with devices in the first wireless network110.

If the access point104receives a message (data frame) from the wireless terminal107, it determines in Step S804whether the wireless terminal107has been registered with the first wireless network110. Since the wireless terminal107has been registered with the registration manager314in this case, the access point104decrypts the message using the encryption key and encryption scheme (included in the first communication parameters111) for the wireless terminal107(Step S806). Regarding messages transmitted from the access point104to the wireless terminal107, they are also encrypted using the encryption key and encryption scheme (included in the first communication parameters111) for the wireless terminal107before transmission. Also, the wireless terminal101, once registered, can conduct encrypted communication using the first communication parameters111as in the case of the wireless terminal107.

In this way, according to the first embodiment, it is possible to set communication parameters on a target device without interrupting communication even if the target device is communicating with another device. It also makes it possible to identify a setting target device by starting to set the communication parameters simultaneously or almost simultaneously on the two devices between which the communication parameters are to be set.

Second Embodiment

A second embodiment of the present invention will be described next. According to the second embodiment, the wireless terminal on which communication parameters are to be set is located in service areas of multiple access points. The embodiment uses the start time of communication parameter setting as the setting identification data for use to identify the setting target device as in the case of the first embodiment.

FIG. 12is a block diagram illustrating a wireless communication system according to the second embodiment. The system includes an access point104, access point1001, wireless terminal101, wireless terminal107, and wireless terminal1004which conduct wireless LAN communication compliant with IEEE 802.11. The same components as those of the first embodiment are denoted by the same reference numerals as the corresponding components of the first embodiment.

The access point1001is equipped with a wireless communication unit1002to construct a wireless LAN. When a button1003is pressed, the access point1001starts automatic setting of communication parameters. The wireless terminal1004is equipped with a wireless communication unit1005. When a button1006is pressed, the wireless terminal1004starts an auto-setting process of communication parameters.

Here, the access point104forms a first wireless network110using first communication parameters111. Also, the wireless terminal107is communicating with the access point104by setting the first communication parameters111. That is, the wireless terminal107has been registered with a registration manager314of the access point104, and the access point104decides that the wireless terminal107has been registered with the wireless network110.

On the other hand, the access point1001forms a second wireless network1007using second communication parameters1008. The wireless terminal1004is communicating with the access point1001by setting the second communication parameters1008. That is, the wireless terminal1004has been registered with a registration manager314of the access point1001, and the access point1001decides that the wireless terminal1004has been registered with the wireless network1007.

The wireless terminal101is located where the service areas of the first wireless network110and second wireless network1007overlap and is a newly joining terminal of the first wireless network110and second wireless network1007. That is, the wireless terminal101is not registered with the registration managers314of the access point104and access point1001.

The access points104and1001have a secret key as an encryption key for a registration request. The wireless terminals101,107, and1004have a public key as an encryption key for a registration request. It is assumed here that the wireless terminal101sets communication parameters in relation to the access point104. Incidentally, the wireless terminals and access points according to the second embodiment have the same configurations as those shown in the block diagrams inFIGS. 2 and 3. The access point104, access point1001, wireless terminal101, wireless terminal107, and wireless terminal1004keep time (in absolute time) using their own real-time clocks. The wireless terminals101,107, and1004have respective synchronized timetables.

FIG. 14shows an example of the present time indicated by the respective real-time clocks of the wireless terminal101, access point104, and access point1001. In this way, there are slight differences in the present time indicated in the wireless terminal101, access point104, and access point1001.

FIG. 15is a diagram illustrating an example of a synchronized timetable possessed by the wireless terminal101according to the second embodiment. The synchronized timetable is stored in the RAM204.

The synchronized timetable contains information about constituent devices of the wireless network, an SSID of the wireless network, and time differences between the constituent devices of the wireless network and owner of the synchronized timetable. The time differences are calculated and updated each time a beacon is received from an appropriate access point. In the example ofFIG. 15, the time kept by the access point104differs from the time kept by the wireless terminal101by +13 seconds while the time kept by the access point1001differs from the time kept by the wireless terminal101by −20 seconds.

Next, a method for setting the communication parameters according to the second embodiment will be described with reference to flowcharts inFIGS. 16 to 19.

FIG. 16is a flowchart explaining a beacon reception process on the wireless terminal101according to the second embodiment.

FIG. 17is a flowchart explaining a communication parameter setting process on the wireless terminal101according to the second embodiment.

Incidentally, the communication parameter setting process on the access point104is the same as the process illustrated in the flowchart inFIG. 8, and thus description thereof will be omitted.

FIG. 18is a flowchart explaining a communication process on the access point1001according to the second embodiment.

FIG. 19is a diagram explaining a communication parameter setting sequence performed among the wireless terminal101, access point104, and access point1001according to the second embodiment.

According to the second embodiment, as in the case of the first embodiment, the wireless terminal101and access point104start setting the communication parameters simultaneously to identify the target device on which the communication parameters will be set.

The access point104is communicating with the wireless terminal107using an encryption key (included in the first communication parameters111) for communication. It periodically transmits a beacon1902(FIG. 19) containing “SSID=ABC” as the SSID of the first wireless network110. The beacon1902also contains, as a time stamp, the time at which it is transmitted. Similarly, the access point1001is communicating with the wireless terminal1004using an encryption key (included in the second communication parameters1008) for communication. It periodically transmits a beacon1901(FIG. 19) containing “SSID=DEF” as the SSID of the second wireless network1007. The beacon1901also contains, as a time stamp, the time at which it is transmitted.

The processes according to the second embodiment will be described in detail below.

Referring toFIG. 16, if the wireless terminal101receives a beacon1902from the access point104in Step S1601, the process advances to Step S1602. In Step S1602, the wireless terminal101compares the value of its own real-time clock212with the time stamp contained in the beacon1902and calculates the difference. In Step S1603, the wireless terminal101stores the difference in the synchronized timetable together with “SSID=ABC” contained in the beacon1902.

On the other hand, if the wireless terminal101receives a beacon1901from the access point1001in Step S1601, the process advances to Step S1602. In Step S1602, the wireless terminal101compares the value of its own real-time clock212with the time stamp contained in the beacon1901and calculates the difference. In Step S1603, the wireless terminal101stores the difference in the synchronized timetable together with “SSID=DEF” contained in the beacon1901. This ends the beacon reception process on the wireless terminal101. Incidentally, the above information is stored by being associated with addresses (MAC addresses or the like) of the access points104and1001which have received the beacons1901and1902and is managed on a per-access-point basis.

Next, to start setting communication parameters, the user of the wireless terminal101presses a communication parameter setting start button103. Consequently, the flowchart shown inFIG. 17is started. In Step S1701, the wireless terminal101reads the time at which the communication parameter setting start button103is pressed from the real-time clock212and stores this process start time. In Step S1702, the wireless terminal101starts scanning the beacon.

On the other hand, the user of the access point104presses a communication parameter setting start button106to start setting communication parameters. Consequently, the process represented by the flowchart inFIG. 8is started. In Step S801, the access point104reads the time at which the communication parameter setting start button106is pressed from the real-time clock312and stores it in the RAM304as setting identification data for the access point104.

In Step S1702, if the wireless terminal101receives a beacon1902from the access point104, it detects the SSID contained in the beacon1902. After that, the process of the wireless terminal101advances to Step S1703to perform the beacon reception process illustrated inFIG. 16. After the beacon reception process, the wireless terminal101transmits an association request1906(FIG. 19) containing the detected SSID to the access point104in Step S1705. Incidentally, although a management/control frame transmission process which involves transmitting a probe request is not described here, it may be performed as in the case of the first embodiment.

Upon receiving the association request1906from the wireless terminal101in Step S905inFIG. 10, the access point104transmits an association response1907(FIG. 19) to the wireless terminal101(Step S907) as in the case of the first embodiment.

The wireless terminal101receives the association response1907in Step S1706and the process advances to Step S1707. In Step S1707, the wireless terminal101adds the difference contained in the synchronized timetable corresponding to “SSID=ABC” of the first wireless network110, i.e., the sender (the access point104) of the association response, to the stored start time, and thereby generates setting identification data. Subsequently, the wireless terminal101encrypts a first registration request message1908(FIG. 19) containing the generated setting identification data with an encryption key (public key) for a registration request. After that, the process of the wireless terminal101advances to Step S1708to transmit the first registration request message1908to the access point104.

Consequently, the access point104can decrypt the message from the unregistered wireless terminal101. It determines in Step S808inFIG. 8whether the received message is a registration request message. Since it is a registration request message1908, the access point104determines in Step S809whether the wireless terminal101is a setting target device based on the received setting identification data. For that, the setting identification data of the wireless terminal101contained in the registration request is compared with the setting identification data possessed by the access point104. If it is found as a result of the comparison that values of the setting identification data match or are within a defined tolerance, it is considered that the wireless terminal101has been validated successfully, and the process of the access point104advances to Step S810. In Step S810, the access point104encrypts a registration acceptance message1909(FIG. 19) containing an encryption key for communication parameter setting with an encryption key (secret key) for a registration request. The access point104transmits the encrypted registration acceptance message1909to the wireless terminal101in Step S811. Upon receiving the registration acceptance message in Step S1709, the wireless terminal101decrypts the registration acceptance message with the encryption key (public key) for a registration request in Step S1710to obtain an encryption key for communication parameter setting. Subsequently, in Step S812and Step S1711, the access point104performs a communication parameter setting sequence1910together with the wireless terminal101. As a result of the communication parameter setting sequence1910, the first communication parameters111are encrypted with the encryption key for communication parameter setting and transmitted to the wireless terminal101by the access point104. The wireless terminal101receives the first communication parameters111and decrypts the parameters with the encryption key for communication parameter setting to set the parameters. Consequently, the wireless terminal101can now conduct communication with devices in the first wireless network110.

Similarly, in communication between the access point1001and wireless terminal101, upon receiving a beacon1901from the access point1001, the wireless terminal101performs the beacon reception process illustrated inFIG. 16in Step S1703. After the beacon reception process, the wireless terminal101transmits an association request1903to the access point1001in Step S1705.

The process performed by the access point1001will be described with reference toFIG. 18. Upon receiving the association request1903(FIG. 19), the access point1001determines in Step S1801whether the communication parameter setting start button1003has been pressed. In this case, the communication parameter setting start button1003has not been pressed in the access point1001. Consequently, a communication parameter setting process is not performed and the received message is processed in a regular communication process (Step S1803). Thus, upon receiving the association request1903from the wireless terminal101in Step S1803, the access point1001performs a regular communication process to transmit an association response1904to the wireless terminal101.

The wireless terminal101receives the association response1904(S1706) and the process advances to Step S1707. In Step S1707, the wireless terminal101adds the difference contained in the synchronized timetable corresponding to “SSID=DEF” of the second wireless network1007, i.e., the sender (the access point1001) of the association response, to the stored start time, and thereby generates setting identification data. Subsequently, the wireless terminal101encrypts a second registration request message1905(FIG. 19) containing the generated setting identification data with an encryption key (public key) for a registration request and transmits it to the access point1001(Step S1708).

Upon receiving the second registration request message1905from the wireless terminal101, the access point1001decides that a message has been received, and performs a regular communication process. However, the message (second registration request message1905), which has been encrypted with the encryption key for a registration request, cannot be decrypted in a regular communication process. Consequently, the access point1001decides that the message is invalid and discards the received message or cuts off the wireless link with the wireless terminal101(Step S1803).

During this time, if the access point104receives the message (date frame) from the wireless terminal107, it determines in Step S804whether the wireless terminal107has been registered with the first wireless network110. It has been in this case, and thus the process of the access point104advances to Step S806to decrypt the massage using the encryption key and encryption scheme (included in the first communication parameters111) for the wireless terminal107.

Regarding messages transmitted from the access point104to the wireless terminal107, they are also encrypted using the encryption key and encryption scheme (included in the first communication parameters111) for the wireless terminal107before transmission.

Also, communication between the access point1001and wireless terminal1004is maintained by the regular communication process (Step S1803) represented by the flow inFIG. 18.

According to the second embodiment, if a plurality of different SSID beacons are received during the period from the press of the button103to the end of the communication parameter setting, the wireless terminal101transmits a registration request message to all the access points which have transmitted the beacons containing the detected SSIDs. However, once communication parameters are set in relation to any of the access points through a communication parameter setting sequence, the registration request message may not be transmitted to the other access points.

According to the second embodiment, since synchronization is achieved with each access point, even if there are a plurality of access points, it is possible to almost eliminate differences in start times serving as setting identification data.

Third Embodiment

According to a third embodiment, the time between the start of communication parameter setting and transmission or reception of a registration request message according to the first embodiment is measured using the timers213and313of the wireless terminal and access point. The time measured by each timer is used as setting identification data. If the values of the setting identification data match or their difference is not larger than a predetermined tolerance, it is considered that the wireless terminal has been validated as a setting target device. Again, the wireless terminal101and access point104start setting the communication parameters simultaneously to identify the target device.

Next, a method for setting the communication parameters according to the third embodiment will be described with reference toFIGS. 20 to 22.

FIG. 20is a flowchart explaining a communication parameter setting process on a wireless terminal101according to the third embodiment.

FIG. 21is a flowchart explaining a communication parameter setting process on an access point104according to the third embodiment. Incidentally, a frame reception process for a frame other than a data frame such as shown inFIG. 21includes the process shown inFIGS. 9 and 10as a part of it.

FIG. 22is a diagram explaining a communication parameter setting sequence performed between the wireless terminal101and access point104according to the third embodiment.

According to the third embodiment, as in the case of the first embodiment, the access point104is communicating with the wireless terminal107using the first communication parameters111. It periodically transmits a beacon containing “SSID=ABC” as the SSID of the first wireless network110.

The processes according to the third embodiment will be described below.

To start setting communication parameters, the user of the wireless terminal101presses the communication parameter setting start button103. Consequently, the process represented by the flowchart inFIG. 20is started. In Step S2001, when the communication parameter setting start button103is pressed, the wireless terminal101starts the timer213to start counting time. In Step S2002, the wireless terminal101starts scanning the beacon.

On the other hand, the user of the access point104presses the communication parameter setting start button106to start setting communication parameters. Consequently, the flowchart shown inFIG. 21is started. In Step S2101, when the communication parameter setting start button106is pressed, the access point104starts the timer313to start counting time.

In Step S2002, if the wireless terminal101receives a beacon2201(FIG. 22) from the access point104, it detects “SSID=ABC” contained in the beacon2201. After detecting the SSID, the wireless terminal101transmits an association request2202containing “SSID=ABC” to the access point104in Step S2004. Incidentally, although a management/control frame transmission process which involves transmitting a probe request is not described here, it may be performed as in the case of the first embodiment.

Upon receiving the association request2202from the wireless terminal101in Step S905(FIG. 10), the access point104transmits an association response2203(FIG. 22) to the wireless terminal101(Step S907) as in the case of the first embodiment.

Consequently, the wireless terminal101receives the association response2203in Step S2005. Next, in Step S2006, the wireless terminal101reads the timer value from the activated timer213and uses the timer value as the setting identification data of the wireless terminal101. Subsequently, the wireless terminal101encrypts a registration request message2204containing the setting identification data with an encryption key (public key) for a registration request and transmits the encrypted registration request message2204(FIG. 22) to the access point104(Step S2007).

Upon receiving the registration request message2204from the wireless terminal101, the access point104decides in Step S2102that a message has been received. Next, in Step S2103, the access point104determines whether the received message is a data frame. In this case, the registration request message2204is a data frame, and thus the process of the access point104advances to Step S2104to determine whether the message-sending device has been registered with the first wireless network110by the registration manager314. In this case, it is determined that the message-sending device has not been registered, and the process advances to Step S2107, where it decrypts the received message with an encryption key (secret key) for a registration request. In Step S2108, the access point104determines whether the message is a registration request message. If it is determined that the message is a registration request message, the process of the access point104advances to Step S2109to read the timer value from the timer313. The access point104sets the time counted between the start of communication parameter setting and reception of the registration request message2204as setting identification data for the access point104. Next, in Step S2110, the access point104compares the setting identification data for the access point104and setting identification data of the wireless terminal101contained in the registration request message2204, and thereby determines whether the setting target device has been validated successfully. According to the third embodiment, the validation based on the setting identification data is considered to be successful if the difference between the values of the setting identification data falls within a certain range such as e.g., five seconds (inclusive). Consequently, the process of the access point104advances to Step S2111to encrypt a registration acceptance message2205containing an encryption key for communication parameter setting with an encryption key (secret key) for a registration request. In Step S2112, the access point104transmits the encrypted registration acceptance message2205(FIG. 22) to the wireless terminal101.

Upon receiving the registration acceptance message2205in Step S2008, the process of the wireless terminal101advances to Step S2009to decrypt the received registration acceptance message2205with the encryption key for a registration request. In Step S2010, the wireless terminal101starts a communication parameter setting sequence2206in relation to the access point104using the encryption key for communication parameter setting contained in the registration acceptance message2205. The access point104also starts a communication parameter setting sequence2206in Step S2113(FIG. 22).

Subsequently, the same processes as in the first embodiment are performed between the wireless terminal101and access point104to set the first communication parameters111on the wireless terminal101. Consequently, the wireless terminal101is registered with the registration manager314of the access point104(Step S2114). The wireless terminal101can now conduct data communication with devices in the first wireless network110. During this time, communication between the access point104and wireless terminal107is maintained as in the case of the first embodiment. In Step S2115, the access point104cuts off the wireless link.

According to the third embodiment, if there are a plurality of access points, i.e., if a plurality of different SSID beacons are detected, the wireless terminal101transmits a registration request message to all the access points which have transmitted the beacons containing the detected SSIDs. Alternatively, the wireless terminal101transmits a registration request message to the access points which have transmitted the beacons containing the detected SSIDs, until communication parameters can be set.

In this way, according to the third embodiment, it is possible to identify the setting target device of communication parameters without synchronizing time between the access point and wireless terminal unlike the first and second embodiments.

Fourth Embodiment

According to a fourth embodiment, a password or other authentication information is used as the setting identification data for validation of a setting target device. Incidentally, the password herein includes a PIN (Personal Identification Number) code or other unique information used to identify a user and device.

In the fourth embodiment described below, a password is used as setting identification data. It is assumed that the password has been set on the access point and that the wireless terminal is required to enter the password. Incidentally, the fourth embodiment includes the access point104, wireless terminal101, and wireless terminal107as in the case of the first embodiment. Also, the wireless terminals and access point according to the fourth embodiment have the same configurations as those shown in the block diagrams inFIGS. 2 and 3.

Next, a method for setting communication parameters according to the fourth embodiment will be described with reference toFIGS. 23 to 25.

FIG. 23is a flowchart explaining a communication parameter setting process on the wireless terminal101according to the fourth embodiment.

FIG. 24is a flowchart explaining a communication parameter setting process on the access point104according to the fourth embodiment.

FIG. 25is a diagram explaining a communication parameter setting sequence performed between the wireless terminal101and access point104according to the fourth embodiment. InFIG. 25,2501to2505are the same as1101to1105inFIG. 1, and thus a description thereof will be omitted.

The processes according to the fourth embodiment will be described below.

To start setting communication parameters, the user of the wireless terminal101presses a communication parameter setting start button103. Consequently, the flowchart shown inFIG. 23is started. When the communication parameter setting start button103is pressed, the wireless terminal101presents a password entry screen on the display unit209in Step S2301. In Step S2302, when the user enters a password, the wireless terminal101stores the password as setting identification data of the wireless terminal101and the process advances to Step S2303, where the wireless terminal101starts scanning a beacon. Subsequent processes on the wireless terminal101are the same as in the first embodiment except that the setting identification data to be put in a registration request message is the password stored in Step S2302, and thus a description thereof will be omitted.

According to the fourth embodiment, it is not necessary to press the communication parameter setting start button106in order for the access point104to start setting communication parameters. The flowchart shown inFIG. 24is always executed.

After a wireless link is established through an association process with the wireless terminal101, if a registration request message2506(FIG. 25) is received from the wireless terminal101, the process of the access point104advances from Step S2401to Step S2402. In Step S2402, the access point104determines whether the received message is a data frame. If the received message is a data frame and the sender of the message is not registered with the registration manager314, the process of the access point104advances from Step S2403to Step S2406to determine whether the received message has been decrypted with an encryption key for a registration request. If the message has been decrypted, the access point104determines in Step S2407whether the message is a registration request message. If it is found as a result of the determination that the message is a registration request message, the process of the access point104advances to Step S2408to compare the setting identification data of the wireless terminal101, i.e., a password, contained in the registration request message2506with a password set on the access point104in advance. If the passwords match, the access point104considers that validation of the setting target device has been successful and the process advances to Step S2409. In Step S2409, the access point104encrypts a registration acceptance message2507(FIG. 25) containing an encryption key for communication parameter setting with an encryption key (secret key) for a registration request. The access point104transmits the encrypted registration acceptance message2507to the wireless terminal101in Step S2410. Subsequent processes on the access point104are the same as in the first embodiment, and thus a description thereof will be omitted.

The first communication parameters111are set on the wireless terminal101through a communication parameter setting sequence2508(FIG. 25) performed between the wireless terminal101and access point104. Consequently, the wireless terminal101can now conduct data communication with devices in the first wireless network110. During this time, communication between the access point104and wireless terminal107is maintained as in the case of the first embodiment.

If there are a plurality of access points, the wireless terminal101transmits a registration request message to all the access points which have transmitted the beacons containing the detected SSIDs. Alternatively, the wireless terminal101transmits a registration request message to the access points which have transmitted the beacons containing the detected SSIDs, until communication parameters can be set.

As described above, according to the fourth embodiment, since a setting target device is validated using a password, communication parameter setting may be started only on the wireless terminal without the need to simultaneously start setting the communication parameters on the access point.

Incidentally, the password may be set on the access point at the start of communication parameter setting. In that case, when the communication parameter setting start button106is pressed on the access point, a password entry screen may be presented in the display unit309, allowing the user to enter a password using the console unit310. This will make it possible to perform the communication parameter setting process even if a password has not been set on the access point in advance.

Fifth Embodiment

In the first to fourth embodiments described above, the beacon scanning on the wireless terminal may be performed before communication parameters are set on the wireless terminal.

Sixth Embodiment

According to a sixth embodiment, when transmitting data from an access point to a wireless terminal as described in the first to fifth embodiments, the access point determines whether the destination wireless terminal has been registered. If the wireless terminal is yet to be registered, the access point transmits the data at minimum transmission power.

FIG. 26is a flowchart explaining a data transmission process on an access point according to the sixth embodiment.

For data transmission, the access point determines in Step S2601whether the destination of a message has been registered. If the destination has been registered, the process of the access point advances to Step S2602to transmit the message at regular transmission power. On the other hand, if the destination device is not registered, the process of the access point advances to Step S2603to transmit the message at lower transmission electric power than the regular transmission power. Incidentally, inFIG. 26, the transmission electric power is reduced to a minimum as an example.

By reducing the transmission electric power in this way upon transmitting data to an unregistered device, it is possible to reduce the risk of data interception and the like.

Seventh Embodiment

The first to sixth embodiments described above may use an encryption/decryption scheme in which the encryption key for a registration request is a common key possessed by the wireless terminal101and access point104rather than a public key.

Eighth Embodiment

The first to seventh embodiments described above may not use an encryption key for a registration request. This will make it possible to set communication parameters for devices which do not have an encryption key for a registration request.

Ninth Embodiment

In the first to eighth embodiments, the encryption scheme contained in the communication parameters also includes the case of no encryption scheme.

Tenth Embodiment

In the first to ninth embodiments, the encryption scheme contained in the communication parameters transmitted to a newly joining terminal during a communication parameter setting sequence may be varied from device to device instead of being the encryption scheme used for the current communication. By varying the encryption scheme from device to device, it is possible to reduce the risk of the communication parameters being intercepted or falsified during the current communication. This also makes it possible to set the communication parameters even if a newly joining terminal does not support the encryption scheme used for the communication.

Eleventh Embodiment

Communication parameter setting performed between access points and wireless terminals has been described in the first to tenth embodiments, but the present invention is also applicable to communication parameter setting performed between wireless terminals without an intervening access point as shown inFIG. 27.

FIG. 27is a diagram showing a configuration of a wireless communication system according to an eleventh embodiment of the present invention. The same components as those of the other embodiments are denoted by the same reference numerals as the corresponding components of the other embodiments.

On a wireless network110, a wireless terminal107and wireless terminal2701are conducting wireless communication directly without an intervening access point (an ad hoc system). The wireless terminal2701has a wireless communication unit2702. When a button2703is pressed, the wireless terminal2701starts an auto setting process of communication parameters. However, in a case that a password is used as in the case of the fourth embodiment, there is no need to press the button2703. On the other hand, a wireless terminal101is a newly joining terminal of the wireless network110. That is, the wireless network110is judged to be an unregistered device by the wireless terminals107and2701. Also, the wireless terminals107,2701, and101have encryption keys for a registration request in the form of a secret key and public key.

The rest of the configuration is the same as the first embodiment if the access point104is replaced by the wireless terminal2701, and thus a description thereof will be omitted. In this case, the wireless terminal2701will have a registration manager.

Twelfth Embodiment

In the first to tenth embodiments, the registration manager may be connected via a network as shown inFIG. 28instead of being installed in an access point. By referring to a registration manager2602via a network, an access point2601will determine whether a wireless terminal which has transmitted a message has been registered. This configuration eliminates the need to install the registration manager2602in the access point2601. Also, it allows information registered in the registration manager2602to be shared by a plurality of access points.

Thus, the embodiments described above make it easy to set communication parameters on a communication apparatus which newly joins a network. They also make it possible to set communication parameters on a newly joining device while continuing ongoing communication with other devices.

Also, since a communication parameter setting process is performed using an encryption key made known to the setting target device of the communication parameters in advance, the communication parameters can be set safely. Besides, since the encryption key is transmitted in encrypted form, it is possible to further improve safety.

Other Embodiments

Embodiments of the present invention have been described in detail above, but the present invention may be applied either to a system consisting of two or more devices or to an apparatus consisting of a single device.

Incidentally, the present invention can also be achieved by a configuration in which a software program that implements the functions of the embodiments described above is supplied to a system or apparatus either directly or remotely and a computer in the system or apparatus reads out and executes the supplied program. In that case, the configuration does not necessarily have to take the form of a program as long as it has program functions.

Thus, program code itself installed on the computer to implement functions and processes of the present invention on the computer also implements the present invention. That is, the present invention as defined in the claims also includes the computer program which implements the functions and processes of the present invention. In that case, the program code may take any form including object code, programs executed by an interpreter, and script data supplied to an OS as long as it has program functions.

The program can also be supplied via an Internet homepage. In that case, the user is supposed to connect to an Internet homepage using a browser on a client computer and download the program itself of the present invention or a compressed self-installing file onto a recording medium such as a hard disk. Also, the program code of the program according to the present invention may be divided into multiple files, which can be downloaded from respective homepages. That is, the present invention as defined in the claims also includes WWW servers which allow multiple users to download program files capable of implementing the functions and processes of the present invention on a computer.

The present invention may also be distributed to users as a storage medium such as a CD-ROM containing the program of the present invention in encrypted form. In that case, only the users who satisfy predetermined conditions are provided with key information for decryption through a download from an Internet homepage and allowed to decrypt and install the program in executable form on a computer using the key information.

The functions of the above embodiments may be implemented not only by the program read out and executed by the computer, but also, for example, by part or all of the actual processing executed, in accordance with instructions from the program, by an OS running on the computer.

Furthermore, the functions of the above embodiments may also be implemented by part or all of the actual processing executed by a CPU or the like contained in a function expansion board inserted in the computer or a function expansion unit connected to the computer if the processing is performed in accordance with instructions from the program code that has been read out of the storage medium and written into memory on the function expansion board or unit.

While the present invention has been described with reference to an exemplary embodiment, it is understood that the invention is not limited to the disclosed exemplary embodiment. The scope of the following claims is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures and functions.

The application claims the benefit of Japanese Application No. 2006-46969 filed Feb. 23, 2006, which is hereby incorporated by reference herein in its entirety.