Network-based method and system for determining a location of user equipment in CDMA networks
AssigneeNokia Corporation
InventorsYrjö Keränen, Timo Viero
Life of this patent
Estimating the term…
Abstract
A method and system for determining a location of a user equipment using RTT measurements from a connected node B and RTT measurement of other node Bs which are not connected to the user equipment. The radio network controller of a network measures RTT of a connected node Bs and then measures RTT of non connected node Bs. Based on the RTT measurement, the distances of the user equipment from each node B is determined. Circles having radii equal to the distances of the user equipment from the nodes are used to determine the user equipment location.
Claims20
A method for determining a geographic location of a user equipment via a location service server in a wireless network, comprising the steps of:
- (a1) receiving, by the wireless network, a request for locating a user equipment;
- (a2) determining if the user equipment is in active communication with a connected transceiver node in response to said request for locating a user equipment, requesting a connection between the user equipment and a selected transceiver node if the user equipment is not in active communication with any transceiver node, and connecting the selected transceiver node with the user equipment so that the selected transceiver node comprises a connected transceiver node;
- (a) determining a value of the transmission timing delay of the user equipment;
- (b) measuring a round trip time of a radio signal between the connected transceiver node and the user equipment, wherein the connected transceiver node is in active communication with the user equipment;
- (c) measuring a round trip time of a radio signal between at least one other transceiver node and the user equipment, wherein the at least one other transceiver node is not in active communication with the user equipment;
- (d) calculating a distance between the user equipment and the connected transceiver node and between the user equipment and each of the at least one other transceiver node using the transmission timing delay determined in said step (a);
- and
- (e) determining the location of the user equipment using the distances calculated in said step (d).
A wireless communication system comprising a core network, a plurality of radio network controllers, a plurality of wireless transceiver nodes for communicating with a user equipment located in a geographical area supported by said transceiver nodes, and a location services server for determining a location of the user equipment, said location services server comprising:
- means for receiving a request for locating a user equipment;
- means for determining if the user equipment is in active communication with a connected transceiver node in response to said request for locating a user equipment, requesting a connection between the user equipment and a selected transceiver node if the user equipment is not in active communication with any transceiver node, and connecting the selected transceiver node with the user equipment so that the selected transceiver node comprises a connected transceiver node;
- means for determining a round trip time for a radio signal from between a user equipment and a connected transceiver node in active communication with the user equipment including means for measuring a time from a beginning of transmission of a downlink transmission signal from the connected transceiver node to the reception of an uplink transmission signal from the user equipment to the connected transceiver node in response to the downlink transmission signal;
- means for determining a round trip time between the user equipment and at least one other non-connected transceiver node which is not in active communication with the user equipment;
- means for determining the distance of the user equipment from the connected transceiver node and the at least one other non-connected transceiver node;
- and
- means for determining a location of the user equipment from the distances of the user equipment from each of the nodes.
Dependencies are inferred from the claim text.