Mobile telephone system for determining a position of a mobile telephone

• US 5,926,765 A
• Filed: 01/21/1997
• Issued: 07/20/1999
• Est. Priority Date: 02/02/1996
• Status: Expired due to Fees

• Current Assignee: NEC Corporation
• Original Assignee: NEC Corporation
• Inventors: Sasaki, Yutaka
• Primary Examiner(s): Urban, Edward F.
• Assistant Examiner(s): Nguyen, Thuan T.
• Application Number:
  US08/786,717
• Time in Patent Office: 910 Days
• Field of Search: 342/450, 342/458, 455/67.1, 455/67.6, 455/115, 455/456, 455/457
• US Class Current: 455/456.1
• CPC Class Codes: G01S 5/14 Determining absolute distances from a plurality of spaced points of known location
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A cordless telephone is disclosed that displays the relative position of a communication partner'"'"'s cordless telephone during conversation between cordless telephones and that includes a received field level detector that measures the received field level; a memory section that inputs and stores the position at which received field level is first detected and positions subsequently detected; a control section that determines the relative position of a communication partner'"'"'s cordless telephone by performing a three-point measurement based on the results of detecting received field level three times and on the resulting detected positions, and a display section that displays the measurement result.

Claims

1. A mobile radiotelephone system comprising a plurality of mobile radio terminals, a switching device for connecting mobile radio terminals to other terminals within the same network or within another network, and connectors which are radio base stations that connect said mobile radio terminals with said switching device;

wherein said mobile radio terminals are provided with;

received level detection means for detecting the received field level of received signals;

calculation means for calculating distance from a mobile radio terminal to a communciation-partner mobile radio terminal by means of the detected received field level;

storage means, that includes an input means, for storing in a memory device a first detected position which is the position at which a received level is first detected by said detection means, and relative positions of a detected positions at which received levels are subsequently detected using first detected position as a reference;

direction detection means for detecting the direction of the position of said communication-partner mobile radio terminal with respect to the mobile radio terminal based on said first detected position and subsequently detected positions; and

displays means for displaying distance calculated by said calculation means and direction detected by said direction detection means.

2. A mobile radiotelephone system according to claim 1 wherein said mobile radio terminal has a transceiver function.

3. A mobile radiotelephone system according claim 2 wherein at least one item of information among received level by said first detection and received levels subsequently detected at different positions is an information item from said connectors.

4. A mobile radiotelephone system according to claim 2 wherein said connector is a connector for household use which is a main unit of a cordless radiotelephone system.

5. A mobile radiotelephone system according to claim 4 wherein said calculated distance and direction are displayed on said connector for household.

6. A mobile radiotelephone system according to claim 4 wherein said calculated distance and direction are displayed on said connector for household.

7. A mobile radiotelephone system according to claim 3 wherein said connector is a connector for household use which is a main unit of a cordless radiotelephone system.

8. A mobile radiotelephone system according to claim 7 wherein said calculated distance and direction are displayed on said connector for household.

9. A mobile radiotelephone system according to claim 1 wherein said mobile radiotelephone system is a digital cordless radiotelephone system.

10. A mobile radiotelephone system according claim 9 wherein at least one item of information among received level by said first detection and received levels subsequently detected at different positions is an information item from said connectors.

11. A mobile radiotelephone system according to claim 9 wherein said connector is a connector for household use which is a main unit of a cordless radiotelephone system.

12. A mobile radiotelephone system according to claim 11 wherein said calculated distance and direction are displayed on said connector for household.

13. A mobile radiotelephone system according to claim 10 wherein said connector is a connector for household use which is a main unit of a cordless radiotelephone system.

14. A mobile radiotelephone system according to claim 13 wherein said calculated distance and direction are displayed on said connector for household.

15. A mobile radiotelephone system according claim 1 wherein at least one item of information among received level by said first detection and received levels subsequently detected at different positions is an information item from said connectors.

16. A mobile radiotelephone system according to claim 15 wherein said connector is a connector for household use which is a main unit of a cordless radiotelephone system.

17. A mobile radiotelephone system according to claim 16 wherein said calculated distance and direction are displayed on said connector for household.

18. A mobile radiotelephone system according to claim 1 wherein said connector is a connector for household use which is a main unit of a cordless radiotelephone system.

19. A mobile radio terminal for communicating with a partner mobile radio terminal in a mobile radiotelephone system, the mobile radio telephone comprising:

detection means for detecting a received field level of a signal received from the partner mobile radio telephone;

a direct-read table for providing a relative distance to the partner mobile radio telephone based on the detected field level, said table including plural field levels and predetermined corresponding distances;

storage means for storing a first position of the mobile radio telephone at which the signal from the partner mobile radio telephone is first detected, and for storing subsequent positions of the mobile radio telephone relative to said first position at which the signal from the partner mobile radio telephone is subsequently detected;

direction determining means for determining a relative direction to the partner mobile radio telephone based on said first and subsequent positions; and

a display for a relative direction and distance to the partner mobile radio telephone from said table and said direction determining means.

20. A mobile radio terminal for communicating with a partner mobile radio terminal in a mobile radiotelephone system, the mobile radio telephone comprising:

detection means for detecting a received field level of a signal received from the partner mobile radio telephone;

calculation means for providing a relative distance to the partner mobile radio telephone based on the detected field level;

storage means for storing a first position of the mobile radio telephone at which the signal from the partner mobile radio telephone is first detected, and for storing subsequent positions of the mobile radio telephone relative to said first position at which the signal from the partner mobile radio telephone is subsequently detected;

direction determining means for determining a relative direction to the partner mobile radio telephone based on said first and subsequent positions; and

a display for a relative direction and distance to the partner mobile radio telephone from said table and said direction determining means.