Apparatus and method for positioning mobile station

1. An apparatus for calculating an enhanced observed time difference from a mobile station and transmitting the enhanced observed time difference to a servicing mobile location center for a location-based service, the apparatus comprising:

means for receiving a location-measuring request and assistance data from the servicing mobile location center;

means for choosing a base transceiver station, the synchronization channel of which is to be measured, based on response time detected from the location-measuring request and a predetermined priority; and

means for calculating an enhanced observed time difference for the chosen base transceiver station and transmitting a location-measuring response, including the calculation result, to the servicing mobile location center,

wherein said predetermined priority is set to a priority order of: [1] an overlap between a channel list included in the assistance data and a list of a number of nearby cells having a higher priority than [2] a broadcast control channel allocation list excepting the channel list included in the assistance data and the list of nearby cells.

2. An apparatus for calculating an enhanced observed time difference from a mobile station and transmitting the enhanced observed time difference to a servicing mobile location center for a location-based service, the apparatus comprising:

a period checker unit adapted to determine if a predetermined period has arrived;

a detector unit adapted to detect the intensity of received signals whenever the period has arrived for detecting the intensity of received signals for an entire channel;

a first memory for storing a database of the intensity of received signals detected by the detector unit; and

a controller unit adapted to choose a base transceiver station, the synchronization channel of which is to be measured, when a location-measuring request and assistance data are received from the servicing mobile location center, based on response time detected from the location-measuring request and a predetermined priority, calculate an enhanced observed time difference for the chosen base transceiver station and transmit a location-measuring response, including the calculation result, to the servicing mobile location center,

wherein said priority is set to a priority order of: [1] an overlap between a channel list included in the assistance data and a list of a number of nearby cells, having a higher priority level than [2] a broadcast control channel allocation list excepting the channel list included in the assistance data and the list of nearby cells, having a higher priority level than [3] a cell having the strongest signal intensity among the remaining base transceiver stations.

3. The apparatus as claimed in claim 2 , further comprising a second memory for storing said priority.

4. The apparatus as claimed in claim 2 , wherein said priority of the base transceiver stations belonging to case [3] follows an order of magnitude of intensity of received signals stored in the first memory.

5. The apparatus as claimed in claim 2 , wherein the list of nearby cells is a list of six nearby cells.

6. A method for calculating an enhanced observed time difference from a mobile station and transmitting the enhanced observed time difference to a servicing mobile location center for a location-based service, the method comprising:

receiving a location-measuring request and assistance data from the servicing mobile location center via a radio resource link protocol;

choosing a base transceiver station, the synchronization channel of which is to be measured, based on response time detected from the location-measuring request and a predetermined priority; and

receiving the synchronization channel of the chosen base transceiver station, calculating an enhanced observed time difference for the chosen base transceiver station, and transmitting a location-measuring response, including the calculation result, to the servicing mobile location center via the radio resource link protocol,

wherein a first priority is assigned to an overlap between a channel list included in the assistance data and a list of a number of nearby cells, and a second priority is assigned to a broadcast control channel allocation list.

7. A method for calculating an enhanced observed time difference from a mobile station and transmitting the enhanced observed time difference to a servicing mobile location center for a location-based service, the method comprising:

determining if a detection period has arrived;

detecting and storing the intensity of received signals for the entire channel when the period has arrived;

receiving a location-measuring request and assistance data via a cordless resource link protocol;

choosing a base transceiver station, the synchronization channel of which can be measured, based on response time detected from the location-measuring request and predetermined priority; and

receiving the synchronization channel of the chosen base transceiver station, calculating an enhanced observed time difference for the chosen base transceiver station and transmit a location-measuring response, including the calculation result, to the servicing mobile location center via the radio resource link protocol,

wherein a first priority is assigned to an overlap between a channel list included in the assistance data and a list of six nearby cells, a second priority is assigned to a broadcast control channel allocation list, and a third priority is assigned to a channel having the strongest signal intensity stored in the second step.

8. The method as claimed in claim 7 , wherein the detection of intensity of received signals is performed before camping on a network.