Methods for Reference Determination in Inter-RAT TDOA

Abstract

A wireless device adapted for operation according to two or more radio access technologies, RATs, obtains positioning reference signal configuration information by sending (602), to a location server, a request for assistance, the request for assistance comprising information about a cell serving the wireless device according to a first RAT. The wireless device receives (604), in response to the request for assistance, positioning reference signal configuration information, the positioning reference signal configuration information identifying one or more signals transmitted according to a second RAT, for measurement by the wireless device. The wireless device measures (606) at least one of the identified one or more signals and may report the measurements and/or estimate a location for the wireless device based on the measurements.

What is claimed is: 
     
         1 . A method, in a user equipment (UE), for obtaining positioning reference signal configuration information, the method comprising:
 sending, to a location server, a request for assistance, the request for assistance comprising information about a cell serving the UE according to a first radio access technology (RAT); and   receiving, in response to the request for assistance, positioning reference signal configuration information, the positioning reference signal configuration information identifying one or more signals transmitted according to a second RAT, for measurement by the UE.   
     
     
         2 . The method of  claim 1 , further comprising reporting one or more measurements for the measured signal or signals. 
     
     
         3 . The method of  claim 1 , further comprising estimating a location for the UE, based on one or more measurements for the measured signal or signals. 
     
     
         4 . The method of  claim 3 , wherein said one or more measurements comprise measurements of relative time differences between different reference signals. 
     
     
         5 . The method of  claim 1 , wherein the method further comprises sending capability information indicating the UE's capability to perform positioning measurements for one or more RATs other than the first RAT. 
     
     
         6 . The method of  claim 5 , wherein the positioning capability information includes one or more of the following:
 a current wireless device configuration with respect to multi-RAT operation;   an indication of one or more RATs according to which the UE is capable of receiving or prefers to receive positioning assistance data;   an indication of one or more RATs according to which the UE is capable of reporting or prefers to report results of positioning measurements;   an indication of one or more RATs for which the UE has a primary cell configured;   an indication of whether the UE is capable of and/or prefers performing positioning measurements of signals according to multiple RATs in parallel;   an indication of a maximum number of cells and/or frequencies for positioning measurements according to each of one or more of supported RATs;   an indication of a set or a range of carrier frequencies for positioning measurements according to each of one or more of supported RATs;   an indication of supported bandwidth(s) according to each of one or more of supported RATs; and   an indication of the UE's numerology capability with respect to each of one or more supported RATs.   
     
     
         7 . The method of  claim 1 , wherein the method further comprises establishing a measurement gap for monitoring signals according to the second RAT, wherein establishing the measurement gap comprises requesting a measurement gap, via the cell serving the UE according to the first RAT, or autonomously setting up the measurement gap. 
     
     
         8 . The method of  claim 1 , wherein the UE is being served by a primary cell operating according to a first RAT, wherein the method further comprises identifying a strongest cell operating according to the second RAT, and wherein the request for assistance includes information identifying the identified strongest cell operating according to the second RAT. 
     
     
         9 . The method of  claim 1 , wherein the request for assistance includes information describing a primary cell serving the UE according to a first RAT. 
     
     
         10 . The method of  claim 9 , wherein the information describing the primary cell serving the UE includes one or more of:
 a cell identifier for the primary cell;   a carrier frequency for the primary cell;   a frequency of a serving synchronization signal block (serving SSB);   an identifier of an SSB;   a tracking reference signal identifier;   an identifier of a channel-state information reference signal; and   timing information for the primary cell.   
     
     
         11 . The method of  claim 1 , wherein the request for assistance includes information describing one or more cells serving the UE other than a primary cell serving the UE. 
     
     
         12 . The method of  claim 1 , wherein the positioning reference signal configuration information comprises timing information for one or more of the identified signals for measurement by the UE, and wherein said measuring the at least one of the identified one or more signals comprises using the timing information. 
     
     
         13 . The method of  claim 12 , wherein the timing information is an offset between a timing of the first RAT and a timing of the second RAT. 
     
     
         14 . A user equipment (UE) configured to obtain positioning reference signal configuration information, the UE comprising:
 transceiver circuitry configured for communicating directly or indirectly with a location server and one or more wireless communication networks; and   processing circuitry operatively associated with the transceiver circuitry and configured to:
 send, to a location server, a request for assistance, the request for assistance comprising information about a cell serving the UE according to a first radio access technology (RAT); and 
 receive, in response to the request for assistance, positioning reference signal configuration information, the positioning reference signal configuration information identifying one or more signals transmitted according to a second RAT, for measurement by the UE. 
   
     
     
         15 . The UE of  claim 14 , wherein the processing circuitry is further configured to report one or more measurements for the measured signal or signals. 
     
     
         16 . The UE of  claim 14 , wherein the processing circuitry is further configured to estimate a location for the UE, based on one or more measurements for the measured signal or signals. 
     
     
         17 . The UE of  claim 16 , wherein said one or more measurements comprise measurements of relative time differences between different reference signals. 
     
     
         18 . The UE of  claim 14 , wherein the UE is being served by a primary cell operating according to a first RAT, wherein the UE is further adapted to identify a strongest cell operating according to the second RAT, and wherein the request for assistance includes information identifying the identified strongest cell operating according to the second RAT.