METHOD AND APPARATUS FOR CONTROLLING AND CALIBRATING WIRELESS RANGE

• US 20080148360A1
• Filed: 12/19/2006
• Published: 06/19/2008
• Est. Priority Date: 12/19/2006
• Status: Active Grant

• Current Assignee: International Business Machines Corporation
• Original Assignee: International Business Machines Corporation
• Inventors: Karstens, Christopher Kent
• Granted Patent: US 7,953,392 B2
• Time in Patent Office: Days
• US Class Current: 726/4
• CPC Class Codes: H04J 3/0667 Bidirectional timestamps, e.g. NTP or PTP for compensation of clock drift and for compensation of propagation delays arrangements for monitoring round trip delays in packet switching networks H04L43/0864
• CPC Class Codes: H04L 63/10 for controlling access to devices or network resources
• CPC Class Codes: H04L 63/107 wherein the security policies are location-dependent, e.g. entities privileges depend on current location or allowing specific operations only from locally connected terminals
• CPC Class Codes: H04W 12/08 Access security
• CPC Class Codes: H04W 12/50 Secure pairing of devices
• CPC Class Codes: H04W 12/61 Time-dependent
• CPC Class Codes: H04W 12/64 using geofenced areas
• CPC Class Codes: H04W 48/04 based on user or terminal location or mobility data, e.g. moving direction, speed
• CPC Class Codes: H04W 88/08 Access point devices

Abstract

A computer implemented method, apparatus, and computer program product for controlling a wireless access point range. In one embodiment, the process identifies a distance between the client device and the wireless access point in response to a request by a client device to access the wireless access point. The process allows the client device to access the wireless access point if the distance from the client device to the wireless access point is within the selected access range for the wireless access point.

Claims

1. A computer implemented method for managing access to a wireless access point range, the computer implemented method comprising:

responsive to a request by a client device to access the wireless access point, identifying a distance between the client device and the wireless access point; and

allowing the client device to access the wireless access point if the distance from the client device to the wireless access point is within the selected access range for the wireless access point.

2. The computer implemented method of claim 1 wherein identifying a distance between the client device and the wireless access point further comprises:

identifying the selected access range for the wireless access point;

receiving a data packet from the client device, wherein the data packet includes a time that the data packet was transmitted to form a transmit clock time; and

identifying an amount of time to transmit the data packet based on a difference between the transmit clock time and a receive time, wherein the receive time is a clock time when a data packet is received.

4. The computer implemented method of claim 1 wherein the selected access range is less than an actual wireless access range for the wireless access point.

5. The computer implemented method of claim 2 wherein identifying the selected access range further comprises:

sending a data packet to a calibration client with a given time-to-live value; and

responsive to receiving a reply data packet from the calibration client, identifying the given time-to-live value as a time-to-live value that is greater than or equal to a desired time-to-live value, wherein the desired time-to-live value defines the selected access range.

6. The computer implemented method of claim 5 further comprising:

responsive to determining that a reply data packet from the calibration client was not received, sending another data packet to the calibration client with a larger time-to-live.

7. The computer implemented method of claim 2 further comprising:

identifying, by a time stamping unit on an Ethernet card, the receive time, wherein the receive time is a clock time in nanoseconds when a data packet is received.

8. The computer implemented method of claim 1 further comprising:

detecting a set of two or more wireless access points;

transmitting a data packet from the client device to each wireless access point;

identifying a distance between the client and each wireless access point based on an amount of time for the data packet to be transmitted between the client device and each wireless access point; and

sending a request to access a wireless access point in the set of two or more wireless access points that is located at a shortest distance from the client device.

3. The computer implemented method of claim 3 wherein identifying a distance from the client to the wireless access point based on the transmit time further comprises:

responsive to determining that an amount of time to transmit the data packet from the wireless access point to the client is less than or equal to a time-to-live value, identifying the distance from the client to the wireless access point as a distance within the user selected access range.

9. A computer implemented method for calibrating a wireless access range, the computer implemented method comprising:

sending a data packet to a calibration client with a given time-to-live value;

responsive to receiving a response from the calibration client, adding the given time-to-live value to a set of desired time-to-live values,; and

selecting a largest time-to-live value from the set of desired time-to-live values to form a selected time-to-live value.

10. The computer implemented method of claim 9 wherein the calibration client is located at a calibration point, and further comprising:

identifying a desired time-to-live value at two or more different calibration points to form the set of desired time-to-live values; and

selecting a largest time-to-live value from the set of time-to-live values to form the selected time-to-live value.

11. The computer implemented method of claim 9 wherein the selected time-to-live value is an amount of time required for a data packet to be sent to a location along a perimeter of a user selected access range of a wireless access point.

12. The computer implemented method of claim 9 further comprising:

responsive to a failure to receive a response from the calibration client, discarding the given time-to-live value and sending another data packet with a new time-to-live value to the calibration client, wherein the new time-to-live value is longer than the given time-to-live value.

13. The computer implemented method of claim 9 further comprising:

selecting a calibration client from a plurality of mobile client computing devices for use in calibrating the wireless access point.

14. The computer implemented method of claim 13 wherein selecting a calibration client further comprises:

specifying a unique identifier of the selected client to form the calibration client.

15. The computer implemented method of claim 9 wherein the calibration point is a location at a point on an outer perimeter of a user selected access range.

16. The computer implemented method of claim 9 wherein the set of time-to-live values are time-to-live values that enable the client to receive the data packet before the given time-to-live value expires.

17. A computer program product comprising:

a computer usable medium including computer usable program code for managing access to a wireless access range, said computer program product comprising;

computer usable program code for identifying a distance between the client device and the wireless access point in response to a request by a client device to access the wireless access point; and

computer usable program code for allowing the client device to access the wireless access point if the distance from the client device to the wireless access point is within the selected access range for the wireless access point.

18. A system for controlling a wireless access range, the system comprising:

a wireless access point, wherein the wireless access point comprises;

a calibration unit, wherein the calibration unit identifies a time-to-live value for defining a selected access range of the wireless access point;

a timer, wherein the timer identifies a clock time that a data packet is received from a client to form a receive time, and wherein the data packet includes a clock time that the data packet was transmitted by the client to form a transmit time; and

a controller, wherein the controller determines a distance from the client to the wireless access point based on the receive time and the transmit time and grants access to a wireless network to the client if the distance from the client to the wireless access point is within the selected access range.

19. The system of claim 18 further comprising:

a time stamping unit on an Ethernet card, wherein the time stamping unit precisely measures the transmit time when a data packet is transmitted and the receive time when a data packet is received.

20. The system of claim 18 wherein the wireless access point is a first wireless access point having a first user selected access range, and further comprising:

a second wireless access point, wherein the second wireless access point has a second user selected access range, and wherein the second user selected access range is a different access range than the first user selected access range.