Wireless communication base station transmission timing offset correction system

• US 20020009974A1
• Filed: 02/28/2001
• Published: 01/24/2002
• Est. Priority Date: 07/17/2000
• Status: Active Grant

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Hitachi, Ltd.
• Inventors: Kuwahara, Mikio, Doi, Nobukazu, Ishifuji, Tomoaki
• Granted Patent: US 6,704,547 B2
• Time in Patent Office: Days
• US Class Current: 455/67.16
• CPC Class Codes: H04J 3/0644 External master-clock
• CPC Class Codes: H04J 3/0685 Clock or time synchronisation in a node; Intranode synchronisation
• CPC Class Codes: H04J 3/0688 Change of the master or reference, e.g. take-over or failure of the master

Abstract

An apparatus, system and method for measuring timing of a signal transmitted from a wireless base station antenna, are disclosed. The apparatus includes an accurate time reception antenna, a cellular antenna that receives the reception time of the signal transmitted from the wireless base station antenna, and a reference clock generator that compares the reception time value and the accurate time value. The system includes an accurate time generator of an accurate time value, a wireless base station antenna that transmits a first signal, and a transmission timing measurement apparatus having a first antenna and a second antenna that receives the accurate time value and the first signal, and that outputs an offset of the first signal from the accurate time value, and may additionally include a center for the storage offsets. The method includes the steps of receiving an accurate time, receiving the reception time transmitted from the wireless base station antenna, receiving, at a reference generator, the reception time value and the accurate time value, and comparing of the reception time value and the accurate time value into a reference output.

Claims

1. A transmission timing measurement system, comprising:

an accurate time generator that transmits at least an accurate time value;

at least one wireless base station antenna that transmits a first signal; and

a transmission timing measurement apparatus having a first antenna and a second antenna, wherein said transmission timing measurement apparatus receives the accurate time value at the first antenna and the first signal at the second antenna, and outputs an offset of the first signal from the accurate time value.

2. The transmission timing measurement system of claim 1, further comprising a center, wherein the offset for at least three of said at least one wireless base station antenna is stored.

3. The transmission timing measurement system of claim 2, further comprising a network over which the offset is communicated to said center from said transmission timing apparatus.

4. The transmission timing measurement system of claim 2, further comprising a terminal, wherein said terminal accesses said center and receives therefrom the offset for at least three of said wireless base station antennae, wherein the at least three offsets received are of at least three wireless base station antennae in communication with said terminal.

5. The transmission timing measurement system of claim 4, wherein said terminal comprises a position locator, wherein said position locator locates a physical position of said terminal according to the communication with said terminal from said at least three wireless base station antennae and according to the at least three offsets.

6. The transmission timing measurement system of claim 5, wherein said transmission timing measurement apparatus comprises said terminal.

7. The transmission timing measurement system of claim 2, further comprising a terminal, and wherein said center further comprises a position locator, wherein said position locator locates a physical position of said terminal according to a communication with said terminal from at least three of said at least one wireless three base station antennae, and according to the offset of the at least three of said at least one wireless base station antennae.

8. The transmission timing measurement system of claim 1, wherein one of said at least one wireless base station antenna and said transmission timing measurement apparatus are co-located.

9. A method for measuring timing of a signal transmitted from a wireless base station antenna, comprising:

receiving, at a first antenna, a signal comprising at least an accurate time value;

outputting, from the first antenna, the accurate time value at reception of the signal transmitted from the wireless base station;

receiving, at a second antenna, the signal transmitted from the wireless base station antenna;

outputting, from the second antenna, a reception time value of the signal transmitted from the wireless base station antenna;

receiving, at a reference generator, the reception time value of the signal transmitted from the wireless base station antenna, and the accurate time value; and

comparing, by the reference generator, of the reception time value and the accurate time value into a reference output.

10. The method of claim 9, wherein the reception time value comprises a transmission time stamp of the signal transmitted from the wireless base station antenna, wherein said comparing comprises:

subtracting a propagation time for the wireless base station antenna to said cellular antenna, from the accurate time value to form a first sum;

comparing the first sum to the transmission time stamp into the reference output.

11. The method of claim 9, further comprising adjusting the timing of the signal transmitted from the wireless base station antenna according to the reference output.

12. The method of claim 9, further comprising storing the reference output.

13. The method of claim 12, further comprising:

accessing by a terminal, of the stored reference output;

receiving, by the terminal, of the reference output for at least three wireless base station antennae from storage, wherein at least three wireless base station antennae are in communication with the terminal.

14. The method of claim 13, further comprising locating a physical position of the terminal according to the communication with the terminal from the at least three wireless base station antennae and according to the at least three reference outputs.

15. A center for position measurement provided with an accumulation unit for accumulating compensation values for the transmission timings of specific signals from a plurality of base stations;

and a communication unit for transmitting, at a request from a terminal, said compensation values accumulated in the accumulating unit to the terminal.

The present invention is not limit ed in scope to the embodiments discussed hereinabove. Various changes and modifications will be apparent to those skilled in the art, and such changes and modifications fall within the spirit and scope of the present invention. Therefore, the present invention is to be accorded the broadest scope consistent with the detailed description, the skill in the art and the following claims.