Method of judging whether radio receiver is inside or outside service area, circuit for judging the same, and radio selective-calling receiver including the circuit

• US 6,198,934 B1
• Filed: 11/04/1998
• Issued: 03/06/2001
• Est. Priority Date: 11/04/1997
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Ohtsuki, Michihito
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Tran, Congvan
• Application Number:
  US09/185,949
• Time in Patent Office: 853 Days
• Field of Search: 455/132, 455/134, 455/140, 455/161.1, 455/161.2, 455/161.3, 455/421, 455/422, 455/434, 455/456, 455/517, 455/525, 455/526, 455/226.2, 455/150.1, 455/32.1, 340/825.44, 340/825.49, 340/825.36, 342/450, 342/457
• US Class Current: 455/456.2
• CPC Class Codes: H04W 8/245 from a network towards a terminal
• CPC Class Codes: H04W 88/022 Selective call receivers

Abstract

There is provided a method of judging whether a radio receiver is in a first area or a second area, the radio receiver dealing with a plurality of frequency channels, the method including the steps, in sequence, of receiving radio signals, detecting a synchronization signal out of the received radio signals, and transmitting a first signal, judging whether the radio receiver transfers outside a range where transmitted radio signals can be received, based on the first signal, detecting an intensity of electro-magnetic wave for each of the frequency channels, when the radio receiver is judged to transfer outside the range, and judging that the radio receiver is situated in the first area, when all of intensities of electro-magnetic waves are smaller than a threshold value, and judging that the radio receiver is situated in the second area, when at least one of intensities of electro-magnetic waves is greater than the threshold value. In accordance with the method, it is possible to accurately judge whether a radio receiver is situated in a first area such as an area to which radio is interrupted to enter, or in a second area such as an area other than a service area where transmitted radio signal can be received.

Claims

1. A method of judging whether a radio receiver is in a first area or a second area, said radio receiver dealing with a plurality of frequency channels, said method comprising the steps, in sequence, of:

(a) receiving and demodulating radio signals;

(b) detecting a synchronization signal out of the thus demodulated radio signals, and transmitting a first signal;

(c) judging whether said radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal detected in said step (b);

(d) detecting an intensity of electro-magnetic wave for each of said frequency channels, when said radio receiver is judged to transfer outside said range; and

(e) judging that said radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are equal to or smaller than a predetermined threshold value, and judging that said radio receiver is situated in said second area, when at least one of intensities of electro-magnetic waves is equal to or greater than said predetermined threshold value.

2. The method as set forth in claim 1, further comprising the step of (f) searching a synchronization signal suitable for said first area, when said radio receiver is judged to be situated in said first area in said step (e).

3. The method as set forth in claim 2, wherein said steps (e) and (f) are carried out on receiving an external input.

4. The method as set forth in claim 3, further comprising the step of storing said external input.

5. The method as set forth in claim 1, further comprising the step of (g) searching a synchronization signal suitable for said second area, when said radio receiver is judged to be situated in said second area in said step (e).

6. The method as set forth in claim 5, wherein said steps (e) and (g) are carried out on receiving an external input.

7. The method as set forth in claim 6, further comprising the step of storing said external input.

8. The method as set forth in claim 1, further comprising the steps of:

(h) storing data about said intensity of electro-magnetic wave; and

(i) judging whether said radio receiver is situated in said first area or said second area, and determining an operation of said radio receiver, based on said data.

10. The method as set forth in claim 2, wherein said radio receiver is judged to be situated within said range, when said synchronization signal is detected, and is judged to be situated outside said range, when said synchronization signal is not detected successively a predetermined number of times.

11. The method as set forth in claim 2, wherein said radio receiver is judged to be situated within said range, when said synchronization signal is detected, and is judged to be situated outside said range, when said synchronization signal is not detected by a predetermined period of time.

12. The method as set forth in claim 2, wherein said plurality of frequency channels are changed or determined in dependence on frequency channels obtained when said radio receiver transfers outside said range.

9. A method of judging whether a radio receiver is in one of a first area and a second area, the radio receiver operable over a plurality of frequency channels, the method comprising the steps of, in sequence:

(a) receiving and demodulating radio signals;

(b) detecting a synchronization signal within said demodulated radio signals, and transmitting a first signal;

(c) judging whether the radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal detected in said step (b);

(d) detecting an intensity of electro-magnetic wave for each of the frequency channels when the radio receiver is judged to transfer outside said range; and

(e) judging that the radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are not greater than a predetermined threshold value and judging that said radio receiver is situated in said second area, when at least one of intensities of electro-magnetic waves is not less than said predetermined threshold value wherein said first area is an area to which radio is interrupted to enter, and said second area is an area other than an area where the transmitted radio signal can be received.

13. A method of judging whether a radio receiver is in one of a first area and a second area, the radio receiver operable over a plurality of frequency channels, said method comprising the steps, in sequence, of:

(a) receiving and demodulating radio signals;

(b) detecting a synchronization signal within said demodulated radio signals, and transmitting a first signal;

(c) judging whether the radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal detected in said step (b);

(d) detecting an intensity of an electro-magnetic wave for each of said frequency channels, when the radio receiver is judged to transfer outside said range; and

(e) judging that the radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are not greater than a predetermined threshold value, and judging that the radio receiver is situated in said second area when at least one of intensities of electro-magnetic waves is not less than said predetermined threshold value; and

searching a synchronization signal suitable for said second area, when said radio receiver is judged to be situated in said second area in said step (e)

wherein said synchronization signal is searched with predetermined frequency channels being switched and further with radio signals being received at an interval longer than an interval determined for battery saving.

14. A method of judging whether a radio receiver is in a first area or a second area, said radio receiver dealing with a plurality of frequency channels, said method comprising the steps, in sequence, of:

(a) receiving and demodulating radio signals;

(b) detecting a synchronization signal out of the thus demodulated radio signals, and transmitting a first signal;

(c) judging whether said radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal detected in said step (b);

(d) detecting an intensity of electro-magnetic wave for each of said frequency channels, when said radio receiver is judged to transfer outside said range;

(e) judging that said radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are equal to or smaller than a predetermined threshold value, and judging that said radio receiver is situated in said second area, when at least one of intensities of electro-magnetic waves is equal to or greater than said predetermined threshold value;

(f) detecting an intensity of electro-magnetic wave; and

(g) searching a synchronization signal suitable for said first or second area, when said radio receiver is judged to be situated in said first or second area in said step (e).

15. The method as set forth in claim 14, wherein said first area is an area to which radio is interrupted to enter, and said second area is an area other than a service area where transmitted radio signal can be received.

16. The method as set forth in claim 14, wherein said synchronization signal is searched with predetermined frequency channels being switched and further with radio signals being received at an interval longer than an interval determined for battery saving.

17. The method as set forth in claim 14, wherein said steps (e) and (g) are carried out on receiving an external input.

18. The method as set forth in claim 17, further comprising the step of storing said external input.

19. The method as set forth in claim 17, wherein said radio receiver is judged to be situated within said range, when said synchronization signal is detected, and is judged to be situated outside said range, when said synchronization signal is not detected successively a predetermined number of times.

20. The method as set forth in claim 17, herein said radio receiver is judged to be situated within said range, when said synchronization signal is detected, and is judged to be situated outside said range, when said synchronization signal is not detected by a predetermined period of time.

21. The method as set forth in claim 14, further comprising the steps of:

(h) storing data about said intensity of electro-magnetic wave; and

(i) judging whether said radio receiver is situated in said first area or said second area, and determining an operation of said radio receiver, based on said data.

22. The method as set forth in claim 14, wherein said plurality of frequency channels are changed or determined independence on frequency channels obtained when said radio receiver transfers outside said range.

23. A circuit for judging whether a radio receiver is in a first area or a second area, said radio receiver dealing with a plurality of frequency channels, said circuit comprising:

(a) a radio receiver for receiving and demodulating radio signals;

(b) a first detector for detecting a synchronization signal out of the thus demodulated radio signals, and transmitting a first signal;

(c) a monitor for judging whether said radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal transmitted from said first detector;

(d) a second detector for detecting an intensity of electro-magnetic wave for each of said frequency channels, when said radio receiver is judged to transfer outside said range; and

(e) a controller for judging that said radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are equal to or smaller than a predetermined threshold value, and judging that said radio receiver is situated in said second area, when at least one of intensities of electro-magnetic waves is equal to or greater than said predetermined threshold value.

24. The circuit as set forth in claim 23, wherein said radio receiver searches a synchronization signal suitable for said first area, when said radio receiver is judged to be situated in said first area.

25. The circuit as set forth in claim 23, wherein said receiver searches a synchronization signal suitable for said second area, when said radio receiver is judged to be situated in said second area.

26. The circuit as set forth in claim 23, further comprising a switch for providing an external input to said radio receiver for causing said radio receiver to judge whether said radio receiver is in said first or second area.

27. The circuit as set forth in claim 23, further comprising a memory for storing data about an intensity of electro-magnetic wave, transmitted from said second detector, and wherein said controller judges whether said radio receiver is situated in said first area or said second area, and determining an operation of said radio receiver, based on said data.

28. The circuit as set forth in claim 27, wherein said memory is an electrically erasable programmable read only memory (EEPROM).

30. The circuit as set forth in claim 24, wherein said monitor judges that said radio receiver is situated within said range, when said synchronization signal is detected, and that said radio receiver is situated outside said range, when said synchronization signal is not detected successively a predetermined number of times.

31. The circuit as set forth in claim 24, wherein said monitor judges that said radio receiver is situated within said range, when said synchronization signal is detected, and that said radio receiver is situated outside said range, when said synchronization signal is not detected by a predetermined period of time.

32. The circuit as set forth in claim 24, wherein said plurality of frequency channels are changed or determined in dependence on frequency channels obtained when said radio receiver transfers outside said range.

29. A circuit for judging whether a radio receiver is in one of a first area and a second area, said radio receiver operable over a plurality of frequency channels, said circuit comprising:

(a) a radio receiver for receiving and demodulating radio signals;

(b) a first detector for detecting a synchronization signal within said demodulated radio signals, and transmitting a first signal;

(c) a monitor for judging whether the radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal transmitted from the first detector;

(d) a second detector for detecting an intensity of electro-magnetic wave for each of said frequency channels, when the radio receiver is judged to transfer outside said range;

(e) a controller for judging that the radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are not greater than a predetermined threshold value and judging that the radio receiver is situated in said second area, when at least one of intensities of electro-magnetic waves is not less than said predetermined threshold value;

wherein said first area is an area to which radio is interrupted to enter, and said second area is an area other than a service area where a transmitted radio signal can be received.

33. A circuit for judging whether a radio receiver is in one of a first area and a second area, said radio receiver operable over a plurality of frequency channels, the circuit comprising:

(a) a radio receiver for receiving and demodulating radio signals and searching for a synchronization signal suitable for the second area when the receiver is judged to be in the second area;

(b) a first detector for detecting a synchronization signal within said demodulated radio signals, and transmitting a first signal;

(c) a monitor for judging whether the radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal transmitted from the first detector;

(d) a second detector for detecting an intensity of electro-magnetic wave for each of said frequency channels, when the radio receiver is judged to transfer outside said range; and

(e) a controller for judging that the radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are not greater than a predetermined threshold value, and judging that the radio receiver is situated in said second area when at least one of intensities of electro-magnetic waves is not less than the predetermined threshold value;

wherein the radio receiver searches said synchronization signal with predetermined frequency channels being switched and further with radio signals being received at an interval longer than an interval determined for battery savings.

34. A radio selective-calling receiver dealing with a plurality of frequency channels, comprising a circuit for judging whether said radio selective-calling receiver is in a first area or a second area, said circuit comprising:

(a) a radio receiver for receiving and demodulating radio signals;

(b) a first detector for detecting a synchronization signal out of the thus demodulated radio signals, and transmitting a first signal;

(c) a monitor for judging whether said radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal transmitted from said first detector;

(d) a second detector for detecting an intensity of electro-magnetic wave for each of said frequency channels, when said radio receiver is judged to transfer outside said range; and

(e) a controller for judging that said radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are equal to or smaller than a predetermined threshold value, and judging that said radio receiver is situated in said second area, when at least one of intensities of electro-magnetic waves is equal to or greater than said predetermined threshold value.

35. The radio selective-calling receiver as set forth in claim 34, wherein said radio receiver searches a synchronization signal suitable for said first area, when said radio receiver is judged to be situated in said first area.

36. The radio selective-calling receiver as set forth in claim 34, wherein said receiver searches a synchronization signal suitable for said second area, when said radio receiver is judged to be situated in said second area.

37. The radio selective-calling receiver as set forth in claim 34, further comprising a switch for providing an external input to said radio receiver for causing said radio receiver to judge whether said radio receiver is in said first or second area.

38. The radio selective-calling receiver as set forth in claim 34, further comprising a memory for storing data about an intensity of electro-magnetic wave, transmitted from said second detector, and wherein said controller judges whether said radio receiver is situated in said first area or said second area, and determining an operation of said radio receiver, based on said data.

39. The radio selective-calling receiver as set forth in claim 37, wherein said memory is an electrically erasable programmable read only memory (EEPROM).

41. The radio selective-calling receiver as set forth in claim 35, wherein said monitor judges that said radio receiver is situated within said range, when said synchronization signal is detected, and that said radio receiver is situated outside said range, when said synchronization signal is not detected successively a predetermined number of times.

42. The radio selective-calling receiver as set forth in claim 35, wherein said monitor judges that said radio receiver is situated within said range, when said synchronization signal is detected, and that said radio receiver is situated outside said range, when said synchronization signal is not detected by a predetermined period of time.

43. The radio selective-calling receiver as set forth in claim 35, wherein said plurality of frequency channels are changed or determined in dependence on frequency channels obtained when said radio receiver transfers outside said range.

40. A radio selective-calling receiver operable over with a plurality of frequency channels, comprising a circuit for judging whether said radio selective-calling receiver is in one of a first area and a second area, said circuit comprising:

(a) a radio receiver for receiving and demodulating radio signals;

(b) a first detector for detecting a synchronization signal within said demodulated radio signals, and transmitting a first signal;

(c) a monitor for judging whether the radio receiver transfers outside a range where transmitted radio signals can be received, based on the first signal transmitted from the first detector;

(d) a second detector for detecting an intensity of electro-magnetic wave for each of said frequency channels, when the radio receiver is judged to transfer outside said range; and

(e) a controller for judging that the radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are not greater than a predetermined threshold value, and judging that said radio receiver is situated in said second area when at least one of intensities of electro-magnetic waves is not less than said predetermined threshold value;

wherein said first area is an area to which radio is interrupted to enter, and said second area is an area other than a service area where transmitted radio signal can be received.

44. A radio selective-calling receiver operable over a plurality of frequency channels, comprising a circuit for judging whether the radio selective-calling receiver is in one of a first area and a second area, the circuit comprising:

(a) a radio receiver for receiving and demodulating radio signals and searching for a synchronization signal suitable for the second area when the radio receiver is judged to be in the second area;

(b) a first detector for detecting a synchronization signal within said demodulated radio signals, and transmitting a first signal;

(c) a monitor for judging whether the radio receiver transfers outside a range where transmitted radio signals can be received, based on said first signal transmitted from said first detector;

(d) a second detector for detecting an intensity of electro-magnetic wave for each of said frequency channels when the radio receiver is judged to transfer outside said range; and

(e) a controller for judging that the radio receiver is situated in said first area, when all of intensities of electro-magnetic waves are not greater than a predetermined threshold value, and judging that the radio receiver is situated in said second area, when at least one of intensities of electro-magnetic waves is not less than said predetermined threshold value;

wherein the radio receiver searches said synchronization signal with predetermined frequency channels being switched and further with radio signals being received at an interval longer than an interval determined for battery saving.