Pulse or digital communications – Spread spectrum – Direct sequence
Reexamination Certificate
1999-12-17
2001-05-08
Pham, Chi (Department: 2631)
Pulse or digital communications
Spread spectrum
Direct sequence
C375S148000, C342S127000, C455S456500
Reexamination Certificate
active
06229844
ABSTRACT:
PRIORITY
This application claims priority to an application entitled “Device and Method for Locating Position of Mobile Station in Mobile Communication System” filed in the Korean Industrial Property Office on Dec. 17, 1998 and assigned Ser. No. 98-55907, the contents of which are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to the field of wireless communications, and in particular, to a receiving device and method in a base station (BS), for locating a mobile station (MS).
2. Description of the Related Art
The FCC (Federal Communication Committee) of the U.S. provides that an MS locating service should be implemented for emergency 911 (E911) public safety services. The FCC requires that wireless carriers be able to locate an E-911 caller with an accuracy of 125 meters in 67% of the cases by October, 2001. Therefore, the CDMA (Code Division Multiple Access) standard (TIA/EIA/IS-95) as well as the IMT-2000 (International Mobile Telecommunication-2000) system makes efforts to provide the MS locating service with use of a reverse link function called “PUF (Power Up Function)”. The PUF is an MS locating scheme in which an MS in an emergency situation transmits probes with gradually increased power to a plurality of adjacent BSs on a reverse channel to inform them of its position so that each of the BSs can calculate the distance between the BS and the MS by estimating the time taken for the signal to reach the BS. The PUF is provided in IS-95B. However, the PUF of IS-95B may decrease system performance since an MS increases its transmit power on its own decision. That is, the increased transmit power of the specific MS creates interference with other MSs. Then, a BS continuously performs power control to reduce the transmit power of the specific MS, thereby increasing system load. Therefore, there exists the need for a continuous positioning service which does not degrade system performance by increasing interference.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide an efficient BS receiving device and method for locating an MS.
It is another object to provide a device and method for locating an MS, which method does not degrade system performance by increasing interference.
It is another object of the present invention to provide a device and method for locating an MS from a reverse channel received from an MS in a BS using a CDMA communication system.
It is a further object of the present invention to provide a device and method for estimating the direction of an MS based on the incident angle of a reverse channel received from the MS in a BS of a mobile communication system.
It is still another object of the present invention to provide a device and method for locating an MS by estimating the direction of the MS based on the incident angle of a reverse channel received from the MS and measuring the distance between a BS and the MS based on a round trip delay in a BS of a mobile communication system.
The present invention provides an MS locating method which makes a continuous positioning service viable without causing the degraded system performance due to increased interference as observed in the PUF of IS-95B. The MS locating method according to the present invention is based on the principle that a BS measures the incident angle of a received MS signal via a reverse link channel and determines the relative direction of the MS with respect to the BS based on the measured incident angle.
REFERENCES:
patent: 5764188 (1998-06-01), Ghosh et al.
patent: 6047192 (2000-04-01), Maloney et al.
patent: 6070079 (2000-05-01), Kuwahara
patent: 6084928 (2000-07-01), Kuwahara
patent: 6112095 (2000-08-01), Wax et al.
patent: 6157339 (2000-12-01), Sato et al.
Dilworth & Barrese LLP
Pham Chi
Phu Phuong
Samsung Electronics Co,. Ltd.
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