Access control system and access control method using the same

1. An access control method of a door operating device that communicates with a user terminal, the access control method comprising:

determining a distance between the door operating device and the user terminal based on a received signal strength corresponding to a transmitted signal from at least one of the door operating device and the user terminal;

determining whether the distance between the door operating device and the user terminal is within a first distance;

establishing a communication connection between the door operating device and the user terminal when the distance between the door operating device and the user terminal is within the first distance;

obtaining first open authentication information when the distance between the door operating device and the user terminal is within the first distance;

determining whether the distance between the door operating device and the user terminal is within a second distance;

obtaining second open authentication information when the distance between the door operating device and the user terminal is within the second distance; and

determining whether the door is open or not based on the open authentication information comprising the first open authentication information and the second open authentication information,

wherein the first open authentication information and the second open authentication information are part of the open authentication information, and

wherein the first open authentication information and the second open authentication information are different from each other.

2. The access control method of claim 1 , wherein the second distance is shorter than the first distance.

3. The access control method of claim 1 , wherein the establishing of the communication connection comprises:

obtaining connection authentication information from the user terminal when the door operating device requests the connection authentication information; and

establishing the communication connection between the door operating device and the user terminal based on the connection authentication information.

4. The access control method of claim 3 , wherein the communication connection between the door operating device and the user terminal is at least one of Bluetooth communication connection, Wi-Fi communication connection, and BLE communication connection.

5. The access control method of claim 1 , wherein the obtaining of the second open authentication information comprises requesting the second open authentication information to the user terminal and obtaining the second open authentication information in response to the request.

6. The access control method of claim 1 , wherein the open authentication information includes at least one of authentication information, user identification information, user terminal identification information, and a password.

7. The access control method of claim 6 , wherein the authentication information includes information on whether at least one of the user terminal and the user is authorized to open the door.

8. The access control method of claim 1 , further comprising adjusting a reference received signal strength used for determining the second distance based on a maximum value of the received signal strength corresponding to the transmitted signal when the transmitted signal includes the open authentication information.

9. The access control method of claim 8 , wherein the adjusting of the reference received signal strength comprises:

setting a received signal strength differed from the maximum value of the received signal strength by a predetermined value as the reference received signal strength.

10. An access control method of a user terminal that communicates with a door operating device, the access control method comprising:

determining a distance between the door operating device and the user terminal based on a received signal strength corresponding to a transmitted signal from at least one of the door operating device and the user terminal;

determining whether the distance between the door operating device and the user terminal is within a first distance;

establishing a communication connection between the door operating device and the user terminal when the distance between the door operating device and the user terminal is within the first distance;

transmitting first open authentication information to the door operating device;

determining whether the distance between the door operating device and the user terminal is within a second distance; and

transmitting second open authentication information to the door operating device for when the distance between the door operating device and the user terminal is within the second distance such that the door operating device obtains open authentication information comprising the first open authentication information and the second open authentication information,

wherein the first open authentication information and the second open authentication information are part of the open authentication information, and

wherein the first open authentication information and the second open authentication information are different from each other.

11. The access control method of claim 10 , wherein the determining of whether the distance between the door operating device and the user terminal is within the second distance comprises:

storing at least one received signal strength corresponding to the transmitted signal from the door operating device; and

adjusting a reference received signal strength used for determining the second distance based on a maximum received signal strength of the stored at least one received signal strength.

12. The access control method of claim 11 , wherein the determining of whether the distance between the door operating device and the user terminal is within the second distance comprises:

setting a received signal strength in a predetermined range based on the maximum received signal strength as the reference received signal strength.

13. A door operating device configured to communicate with a user terminal, the door operating device comprising:

a communication unit; and

a control unit configured to:

determine a distance from the user terminal based on a strength of a signal transmitted from the user terminal,

establish a communication connection with the user terminal and acquire the first open information through the communication connection using the communication unit from the user terminal when the distance from the user terminal is within a first distance,

acquire second open authentication information from the user terminal using the communication unit when the distance between the user terminals is changed from the first distance to a second distance, and

determine whether the door is open or not based on open authentication information comprising the first open authentication information and the second open authentication information,

wherein the first open authentication information and the second open authentication information are part of the open authentication information, and

wherein the first open authentication information and the second open authentication information different from each other.

14. A non-transitory computer readable medium configured to store program code instructions, when executed by a processor, cause the processor to perform steps comprising:

determining a distance between a door operating device and a user terminal based on a received signal strength corresponding to a transmitted signal from at least one of the door operating device and the user terminal;

determining whether the distance between the door operating device and the user terminal is within a first distance;

establishing a communication connection between the door operating device and the user terminal when the distance between the door operating device and the user terminal is within the first distance;

obtaining first open authentication information when the distance between the door operating device and the user terminal is within the first distance;

determining whether the distance between the door operating device and the user terminal is within a second distance;

obtaining second open authentication information when the distance between the door operating device and the user terminal is within the second distance; and

determining whether the door is open or not based on the open authentication information comprising the first open authentication information and the second open authentication information,

wherein the first open authentication information and the second open authentication information. are part of the open authentication information, and

wherein the first open authentication information and the second open authentication information are different from each other.

15. A non-transitory computer readable medium configured to store program code instructions, when executed by a processor, cause the processor to perform steps comprising:

determining a distance between a door operating device and a user terminal based on a received signal strength corresponding to a transmitted signal from at least one of the door operating device and the user terminal;

determining whether the distance between the door operating device and the user terminal is within a first distance;

establishing a communication connection between the door operating device and the user terminal when the distance between the door operating device and the user terminal is within the first distance;

transmitting first open authentication information to the door operating device;

determining whether the distance between the door operating device and the user terminal is within a second distance; and

transmitting second open authentication information to the door operating device when the distance between the door operating device and the user terminal is within the second distance such that the door operating device obtains open authentication information comprising the first open authentication information and the second open authentication information,

wherein the first open authentication information and the second open authentication information are part of the open authentication information, and

wherein the first open authentication information and the second open authentication information different from each other.