Positioning Node, User Equipment and Methods Therein

Abstract

Embodiments herein relate to a method in a user equipment for enabling positioning of the user equipment in a radio communications network. The user equipment is served in a first cell controlled by a radio network node. The user equipment knows or can obtain a system frame number of at least one cell. The user equipment, a positioning node, and the radio network node are included in the radio communications network. The user equipment receives, from the positioning node, a message comprising positioning assistance data, wherein the positioning assistance data comprises information associated with the at least one cell for which the system frame number is known or can be obtained by the user equipment. The user equipment also performs a positioning measurement using the positioning assistance data and the system frame number of the at least one cell to enable positioning of the user equipment.

What is claimed is: 
     
         1 . A method in a user equipment for enabling positioning of the user equipment in a radio communications network, wherein the user equipment is served in a first cell controlled by a radio network node, wherein the user equipment knows or can obtain a system frame number of at least one cell, and wherein the user equipment, a positioning node, and the radio network node are included in the radio communications network, the method comprising:
 receiving, from the positioning node, a message comprising positioning assistance data, wherein the positioning assistance data comprises information associated with the at least one cell for which the system frame number is known or can be obtained by the user equipment; and   performing a positioning measurement using the positioning assistance data and the system frame number of the at least one cell to enable positioning of the user equipment.   
     
     
         2 . The method of  claim 1 , where the positioning assistance data comprises Observed Time Difference of Arrival (OTDOA) assistance data, and wherein the at least one cell is included in the OTDOA assistance data either as a reference cell, or in a neighbor cell list. 
     
     
         3 . The method of  claim 1 , wherein the performing comprises calculating a slot number of another cell in the positioning assistance data based on the system frame number of the at least one cell, and wherein the slot number is to be used when measuring differences in time of arrival of reference signals of the cells when performing the positioning measurement. 
     
     
         4 . The method of  claim 3 , wherein the calculating is based on a slot number of the at least one cell with the known system frame number, an expected value of a reference signal time difference, and/or an offset value between timing of the at least one cell and the other cell. 
     
     
         5 . The method of  claim 1 , wherein the positioning measurement is performed on a reference signal, and wherein the reference signal is a positioning reference signal or a cell-specific reference signal. 
     
     
         6 . The method of  claim 1 , further comprising acquiring the system frame number of at least one cell comprised in the positioning assistance data prior to performing positioning measurements. 
     
     
         7 . The method of  claim 6 , wherein the at least one cell is a reference cell in the positioning assistance data when the system frame number of the reference cell is not known or uncertain. 
     
     
         8 . The method of  claim 7 , wherein the reference cell is not a cell serving the user equipment. 
     
     
         9 . The method of  claim 6 , wherein said acquiring the system frame number is triggered when receiving the message comprising the positioning assistance data if a cell serving the user equipment is not included in the positioning assistance data. 
     
     
         10 . The method of  claim 6 , wherein said acquiring the system frame number is triggered when receiving the message comprising the positioning assistance data if no cell for which the user equipment knows the system frame number is included in the positioning assistance data. 
     
     
         11 . The method of  claim 1 :
 wherein the received message further comprises a serving cell indicator indicating a cell registered in the positioning node serving the user equipment; and   wherein when the first cell is not indicated by the serving cell indicator, the user equipment sends a request for the positioning assistance data of the first cell to the positioning node.   
     
     
         12 . The method of  claim 11 , further comprising:
 requesting measurement reconfiguration when the first cell has a different frequency than the indicated serving cell in the received message.   
     
     
         13 . The method of  claim 1 , further comprising sending information to the positioning node indicating the first cell as the cell serving the user equipment. 
     
     
         14 . A method in a positioning node for enabling positioning of a user equipment in a radio communications network, wherein the user equipment is served in a first cell controlled by a radio network node, and wherein the positioning node, the user equipment, and the radio network node are included in the radio communications network, the method comprising:
 determining at least one cell for which a system frame number is known or can be obtained by the user equipment;   generating a message comprising positioning assistance data, wherein the positioning assistance data comprises information associated with the at least one cell; and   transmitting the message to the user equipment, wherein the positioning assistance data in the message enables positioning of the user equipment.   
     
     
         15 . A user equipment for enabling positioning of the user equipment in a radio communications network, wherein the user equipment is configured to be served in a first cell controlled by a radio network node, wherein the user equipment is configured to know or to obtain a system frame number of at least one cell, and wherein the user equipment, a positioning node, and the radio network node are included in the radio communications network, the user equipment comprising:
 a receiver configured to receive, from the positioning node, a message comprising positioning assistance data, wherein the positioning assistance data comprises information associated with the at least one cell for which the system frame number is known or can be obtained by the user equipment; and   a processing circuit configured to perform a positioning measurement using the positioning assistance data and the system frame number of the at least one cell to enable positioning of the user equipment.   
     
     
         16 . The user equipment of  claim 15 , wherein the positioning assistance data comprise Observed Time Difference of Arrival (OTDOA) assistance data, and wherein the at least one cell is comprised in the OTDOA assistance data either as a reference cell, or in a neighbor cell list. 
     
     
         17 . A positioning node for enabling positioning of a user equipment in a radio communications network, wherein the user equipment is served in a first cell controlled by a radio network node, the positioning node comprising:
 a determining circuit configured to determine at least one cell for which a system frame number is known or can be obtained by the user equipment;   a generating circuit configured to generate a message comprising positioning assistance data, wherein the positioning assistance data comprises information associated with the at least one cell; and   a transmitting circuit configured to transmit the message to the user equipment, wherein the positioning assistance data in the message enables positioning of the user equipment.