Proximity sensing method using loopback mechanism and wireless communications device thereof

• US 9,386,527 B2
• Filed: 10/21/2013
• Issued: 07/05/2016
• Est. Priority Date: 01/04/2013
• Status: Active Grant

• Current Assignee: Xueshan Technologies Inc. (Wi-LAN Inc.)
• Original Assignee: MediaTek Singapore Pte. Ltd. (MediaTek, Inc.)
• Inventors: Shana'a, Osama K A, Lien, Wee-Liang, Low, Eng-Chuan, Leow, Chin-Heng, Choke, Tieng Ying, Sun, Yuan
• Primary Examiner(s): Urban, Edward
• Assistant Examiner(s): Mathew, Max
• Application Number:
  US14/058,305
• Publication Number:
  US 20140194057A1
• Time in Patent Office: 988 Days
• Field of Search: 455/41.1, 455/41.2, 235/439
• US Class Current: 1/1
• CPC Class Codes: H04W 52/0241 where no transmission is received, e.g. out of range of the transmitter
• CPC Class Codes: H04W 52/0245 according to signal strength
• CPC Class Codes: H04W 52/0254 detecting a user operation or a tactile contact or a motion of the device
• CPC Class Codes: Y02D 30/70 in wireless communication networks

Abstract

A proximity sensing method employed by a wireless communications device includes the steps of: performing a first predetermined operation to detect a presence of at least a transponder in the proximity of the wireless communications device; when the presence of a transponder in the proximity of the wireless communications device is not detected by the first predetermined operation, performing a second predetermined operation to obtain a first characteristic value and after a period of time, performing the second predetermined operation to obtain a second characteristic value sequentially; checking if the first characteristic value and the second characteristic value satisfy a predetermined criteria; and when the predetermined criterion is satisfied, performing the first predetermined operation again to check the presence of the transponder in the proximity of the wireless communications device.

Claims

1. A proximity sensing method employed by a wireless communications device, comprising:

performing a first predetermined operation to detect presence of at least a transponder in the proximity of the wireless communications device;

when the presence of a transponder in the proximity of the wireless communications device is not detected by the first predetermined operation, performing a second predetermined operation to obtain a first characteristic value and after a period of time, performing the second predetermined operation to obtain a second characteristic value sequentially;

checking if the first characteristic value and the second characteristic value satisfy a predetermined criterion; and

when the predetermined criterion is satisfied, performing the first predetermined operation again to check the presence of the transponder in the proximity of the wireless communications device.

2. The proximity sensing method of claim 1, wherein the first predetermined operation is a polling operation for a connection establishment.

3. The proximity sensing method of claim 1, wherein the second predetermined operation transmits a probe signal to an antenna matching network of the wireless communications device, receives a loopback signal of the probe signal, and obtains a characteristic value according to the loopback signal, where the first characteristic value and the second characteristic value are characteristic values obtained by the second predetermined operation at different times.

4. The proximity sensing method of claim 3, wherein the probe signal is a single-tone signal, a square wave signal, an arbitrary signal, a triangular signal or a white noise signal.

5. The proximity sensing method of claim 3, wherein the probe signal is transmitted based on a first local oscillator (LO) frequency, and the loopback signal is received based on a second LO frequency different from the first LO frequency.

6. The proximity sensing method of claim 1, wherein the predetermined criterion is satisfied when a difference between the first characteristic value and the second characteristic value exceeds a threshold.

7. The proximity sensing method of claim 1, further comprising:

after performing the second predetermined operation to obtain the first characteristic value, the wireless communications device enters into a sleep mode, and then leaves the sleep mode after the period of time in order to perform the second predetermined operation to obtain the second characteristic value.

8. The proximity sensing method of claim 1, further comprising:

when the first predetermined operation is performed again and the presence of a transponder in the proximity of the wireless communications device is not detected, performing the second predetermined operation to update the first characteristic value.

9. The proximity sensing method of claim 1, wherein the wireless communications device is a near field communications device.

10. A wireless communications device having proximity sensing capability, comprising:

a first circuit, for performing a first predetermined operation to detect a presence of at least a transponder in the proximity of the wireless communications device, and when the presence of a transponder in the proximity of the wireless communications device is not detected by the first predetermined operation, performing a second predetermined operation to obtain a first characteristic value and after a period of time, performing the second predetermined operation to obtain a second characteristic value sequentially; and

a second circuit, for checking if the first characteristic value and the second characteristic value satisfy a predetermined criteria;

wherein when the predetermined criterion is satisfied, the first circuit performs the first predetermined operation again to check the presence of the transponder in the proximity of the wireless communications device.

11. The wireless communications device of claim 10, wherein the first predetermined operation is a polling operation for a connection establishment.

12. The wireless communications device of claim 10, wherein the first circuit comprises:

a transmitter, for transmitting a polling command signal when performing the first predetermined operation, and transmitting a probe signal to an antenna matching network of the wireless communications device when performing the second predetermined operation; and

a receiver, for receiving a response signal of the polling command signal when performing the first predetermined operation, and receiving a loopback signal of the probe signal and accordingly obtaining a characteristic value according to the loopback signal when performing the second predetermined operation, where the first characteristic value and the second characteristic value are characteristic values obtained by the second predetermined operation at different times;

wherein the second predetermined operation transmits the probe signal, receives the loopback signal of the probe signal, and obtains a characteristic value according to the loopback signal.

13. The wireless communications device of claim 12, wherein the probe signal is a single-tone signal, a square wave signal, an arbitrary signal, a triangular signal or a white noise signal.

14. The wireless communications device of claim 12, further comprising

a first local oscillator, for generating a first local oscillation frequency such that the transmitter transmits the probe signal on the first local oscillator frequency;

and

a second local oscillator, for generating a second local oscillation frequency such that the receiver receives the loopback signal on the second LO frequency;

wherein the first local oscillator frequency is different from the second local oscillator frequency.

15. The wireless communications device of claim 11, wherein the second circuit determines the predetermined criterion is satisfied when a difference between the first characteristic value and the second characteristic value exceeds a threshold.

16. The wireless communications device of claim 11, wherein after performing the second predetermined operation to obtain the first characteristic value, the second circuit controls the wireless communications device to enter into a sleep mode, and then leaves the sleep mode after the period of time in order to perform the second predetermined operation to obtain the second characteristic value.

17. The wireless communications device of claim 11, wherein when the first circuit performs the first predetermined operation again and the presence of a transponder in the proximity of the wireless communications device is not detected, the first circuit performs the second predetermined operation to update the first characteristic value.

18. The wireless communications device of claim 11, wherein the wireless communications device is a near field communications device.