Method, system, and apparatus for detecting a position of a terminal in a network

• US 20040046693A1
• Filed: 06/18/2003
• Published: 03/11/2004
• Est. Priority Date: 09/06/2002
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Doi, Nobukazu, Yano, Takashi, Shida, Masaaki, Ogino, Atsushi, Yamasaki, Ryota, Tsunehara, Katsuhiko, Suzuki, Hideya
• Granted Patent: US 7,167,712 B2
• Time in Patent Office: Days
• US Class Current: 342/357.08
• CPC Class Codes: G01S 5/0054 of actual mobile position, i.e. position calculation on base station
• CPC Class Codes: G01S 5/0081 Transmission between base stations
• CPC Class Codes: G01S 5/021 Calibration, monitoring or correction G01S5/0252 takes precedence
• CPC Class Codes: G01S 5/02216 Timing or synchronisation of the receivers
• CPC Class Codes: G01S 5/06 Position of source determined by co-ordinating a plurality of position lines defined by path-difference measurements G01S5/12 takes precedence
• CPC Class Codes: H04W 64/00 Locating users or terminals or network equipment for network management purposes, e.g. mobility management

Abstract

A method, system, and apparatus are provided for detecting a position of a terminal in a network accurately without a GPS receiver. In one example, a method for locating a position of a terminal includes calculating a position of a base station; detecting a clock time difference between the base station and another base station; measuring a reception timing of a signal received by the base station from the terminal; and locating the position of the terminal using at least the position of the base station, the clock time difference, and the reception timing.

Claims

1. A method for locating a position of a terminal, the method comprising:

detecting a clock time difference between the base station and another base station;

measuring a reception timing of a signal received by the base station from the terminal; and

locating the position of the terminal using at least the position of the base station, the clock time difference, and the reception timing,

wherein a frequency channel is used to measure the reception timing of a signal received from the terminal and to detect the clock time difference among the base stations.

2. The method of claim 1, wherein the step of detecting comprises transmitting at least wireless signal from the base station to the other base station.

3. The method of claim 2, wherein the signal received by the base station from the terminal is transmitted in response to reception, at the terminal, of the wireless signal transmitted from the base station to detect the clock time difference.

4. The method of claim 1, further comprising a step of instructing the base stations, by a server, to monitor the frequency channel.

5. The method of claim 1, further comprising detecting one or more additional clock time differences between the base station and one or more additional base stations, wherein the step of locating the position further comprises using the one or more additional clock time differences.

6. The method of claim 1, wherein the step of detecting a clock time difference comprises:

repeating wireless communications from the base station to the other base stations; and

detecting a ratio of a clock speed of one of the other base stations to a clock speed of another of the other base stations, and

the step of locating the position of the terminal further comprises using the ratio for locating the position of the terminal.

7. The method of claim 1, wherein the step of detecting clock time difference is carried out in a wireless local area network (LAN) through communications from the base station to the other base stations.

8. The method of claim 7, wherein the base station and the other base station repeat wireless communication in a wireless local area network in order to detect differences in clock speed.

9. The method of claim 1, wherein a synchronization field pattern of a preamble of the signal received from the terminal is used for measuring the reception timing.

10. A server configured to manage procedures for locating a position of a terminal, the server comprising:

a channel control instruction component configured to instruct base stations to monitor a frequency channel used for locating the position of the terminal;

a sending request component configured to send via a base station a request for the terminal to send a terminal signal to the frequency channel;

a measurement result receiving component configured to receive measurement results from each of the other base stations, the measurement results being associated with reception timings of signals received from the base station and from the terminal; and

a position calculation component configured to calculate the position of the terminal,

wherein the frequency channel is used for sending the request for the terminal to send a terminal signal and for sending the signal received from the terminal.

11. The server of claim 10, wherein the base station is configured to send a base station signal to other base stations, wherein the other base stations are each configured to measure a reception timing of the base station signal received from the base station, wherein the other base stations are further configured to measure a reception timing of the terminal signal received from the terminal.

12. The server of claim 11, wherein the terminal, the base station, and the other base stations are configured to repeat wireless communications, wherein the base station is configured to detect a ratio of a clock speed of one of the other base stations to a clock speed of another of the other base stations, and the position calculation component is further configured to use the ratio for locating the position of the terminal.

13. The server of claim 10, wherein each component of the server is made up of at least one of software and hardware.

14. The server of claim 10, wherein delay times of receiving processing at each base station are accumulated, wherein the position calculation component is further configured to use each accumulated delay in calculating the position of the terminal.

15. The server of claim 10, wherein the base station and the frequency channel are chosen according to a position of an initial base station that relays a position location request issued from the terminal.

16. The server of claim 15, wherein the server controls transmission power, for the frequency channel, of base stations not used for locating the position of the terminal, according to the base station used for locating the position of the terminal and the frequency channel.

17. A base station for a terminal location system locating a position of a terminal using positions of base stations, clock time difference between the base station and another base station and a reception timing of a signal received by the base station from the terminal, comprising:

a communication block for receiving signals transmitted from the terminal and the another base station;

a control block for controlling the communication block; and

a storage block for storing at least a part of signals received from the terminal and the another base station and clock information associated with the storing for determining the clock time difference and the reception timing, wherein the control block controls the communication block to receive the signals from the terminal and the another base station via a frequency channel.

18. The base station of claim 17, wherein the at least a part of signals and the clock time information associated with the storing are transmitted to a server for calculating the location of the terminal.

19. The base station of claim 17, wherein the control block calculates reception timings of the signals from the terminal and the another base station and said reception timings are transmitted to a server for calculating the location of the terminal.

20. The base station of claim 17, wherein the at least a part of signals stored in the storing block include a synchronization field patterns of preambles of the signals.