Position determination of a wireless device

Abstract

There is provided a method for position determination of a wireless device. The method is performed by the wireless device. The method comprises detecting, whilst being operatively connected to a source radio access technology (RAT) an indicator requiring a handover of the wireless device to a target RAT. The method comprises starting a positioning detection procedure of the wireless device before being handed over to the target RAT, the positioning detection procedure involving processing of positioning measurements. The method comprises keeping the positioning measurements of the positioning detection procedure whilst the wireless device being handed over from the source RAT to the target RAT. The method comprises continuing the positioning detection procedure using the positioning measurements whilst being operatively connected to the target RAT.

1 . A method for position determination of a wireless device, the method being performed by the wireless device, the method comprising:
 detecting, whilst being operatively connected to a source radio access technology (RAT) an indicator requiring a handover of the wireless device to a target RAT;   starting a positioning detection procedure of the wireless device before being handed over to the target RAT, the positioning detection procedure involving processing of positioning measurements;   keeping the positioning measurements of the positioning detection procedure whilst the wireless device being handed over from the source RAT to the target RAT; and   continuing the positioning detection procedure using the positioning measurements whilst being operatively connected to the target RAT.   
     
     
         2 . The method according to  claim 1 , wherein the indicator is an emergency call indicator. 
     
     
         3 . The method according to  claim 1 , wherein continuing the positioning detection procedure comprises:
 completing said positioning detection procedure so as to determine a position of the wireless device; and   providing the position to the target RAT.   
     
     
         4 . The method according to  claim 1 , wherein continuing the positioning detection procedure comprises:
 providing the positioning measurements to the target RAT.   
     
     
         5 . The method according to  claim 1 , further comprising, in response to detecting the indicator:
 sending a non-access, stratum (NAS) extended service request with a service type information element set to emergency call to the source RAT.   
     
     
         6 . The method according to  claim 1 , further comprising, in response to detecting the indicator:
 requesting a radio resource control (RRC) connection establishment with information element establishment cause set to emergency to the source RAT.   
     
     
         7 . The method according to  claim 1 , wherein being handed over from the source RAT to the target RAT comprises:
 receiving information elements for redirection of the wireless device to the target RAT.   
     
     
         8 . The method according to  claim 7 , wherein the information elements for redirection are received in a radio resource control (RRC) connection release message. 
     
     
         9 . The method according to  claim 1 , wherein the wireless device is not capable of performing Internet protocol multimedia subsystem (IMS) emergency calls in the source RAT. 
     
     
         10 . The method according to  claim 1 , wherein the handover involves a circuit switched (CS) fallback of the wireless device. 
     
     
         11 . The method according to  claim 1 , wherein the handover involves a single radio voice call continuity (SRVCC) procedure. 
     
     
         12 . The method according to  claim 1 , wherein the positioning detection procedure involves performing a network initiated location request (NILR) positioning procedure whilst being operatively connected to the source RAT. 
     
     
         13 . The method according to  claim 1 , wherein the positioning measurements are global navigation satellite system (GNSS) measurements. 
     
     
         14 . The method according to  claim 13 , wherein the GNSS measurements are assisted GNSS (A-GNSS) assistance data items received from an evolved serving mobile location center (E-SMLC). 
     
     
         15 . The method according to  claim 1 , wherein the source RAT is a Long Term Evolution (LTE) compliant network. 
     
     
         16 . The method according to  claim 1 , wherein the target RAT is non-Long Term Evolution (non-LTE) compliant network. 
     
     
         17 . A method for position determination of a wireless device, the method being performed by a mobility management node, the method comprising:
 detecting an indication of a wireless device being operatively connected to a source radio access technology (RAT) the indication requiring a handover of the wireless device to a target RAT; in response thereto:   sending a Location Services Application Protocol (LCS-AP) location request message to an evolved serving mobile location center (E-SMLC) of the wireless device; and   sending, upon fulfilment of a criterion relating to the indication of the wireless device, a LCS-AP location abort request message to the E-SMLC.   
     
     
         18 . The method according to  claim 17 , wherein the indicator is an emergency call indicator. 
     
     
         19 . The method according to  claim 17 , further comprising:
 monitoring transmission of assisted GNSS (A-GNSS) assistance data items from the E-SMLC to the wireless device; and   wherein the criterion is fulfilled when a configured number of data items have been sent from the E-SMLC to the wireless device.   
     
     
         20 . The method according to  claim 17 , wherein the criterion is fulfilled when a configured time interval starting at the detection of the indication has finished. 
     
     
         21 . The method according to  claim 17 , further comprising:
 sending an S1-AP context modification request comprising a circuit switched fallback indicator to the source RAT upon having sent the LCS-AP location abort request.   
     
     
         22 . A wireless device for position determination of the wireless device, the wireless device comprising a processing unit configured to:
 detect, whilst being operatively connected to a source radio access technology (RAT) an indicator requiring a handover of the wireless device to a target RAT;   start a positioning detection procedure of the wireless device before being handed over to the target RAT, the positioning detection procedure involving processing of positioning measurements;   keep the positioning measurements of the positioning detection procedure whilst the wireless device being handed over from the source RAT to the target RAT; and   continue the positioning detection procedure using the positioning measurements whilst being operatively connected to the target RAT.   
     
     
         23 . A mobility management node for position determination of a wireless device, the mobility management node comprising a processing unit configured to:
 detect an indication of a wireless device being operatively connected to a source radio access technology (RAT) the indication requiring a handover of the wireless device to a target RAT; in response thereto:   send a Location Services Application Protocol (LCS-AP) location request message to an evolved serving mobile location center (E-SMLC) of the wireless device; and   send, upon fulfilment of a criterion relating to the indication of the wireless device, a LCS-AP location abort request message to the E-SMLC.   
     
     
         24 . The mobility management node according to  claim 23 , wherein the mobility management node is a Mobility Management Entity (MME). 
     
     
         25 . A nontransitory computer-readable medium comprising a computer program for position determination of a wireless device, the computer program comprising computer program code which, when run on a processing unit of the wireless device, causes the processing unit to:
 detect, whilst being operatively connected to a source radio access technology (RAT) an indicator requiring a handover of the wireless device to a target RAT;   start a positioning detection procedure of the wireless device before being handed over to the target RAT, the positioning detection procedure involving processing of positioning measurements;   keep the positioning measurements of the positioning detection procedure whilst the wireless device being handed over from the source RAT to the target RAT; and   continue the positioning detection procedure using the positioning measurements whilst being operatively connected to the target RAT.   
     
     
         26 . A nontransitory computer-readable medium comprising a computer program for position determination of a wireless device, the computer program comprising computer program code which, when run on a processing unit of a mobility management node, causes the processing unit to:
 detect an indication of a wireless device being operatively connected to a source radio access technology (RAT) the indication requiring a handover of the wireless device to a target RAT; in response thereto:   send a Location Services Application Protocol (LCS-AP) location request message to an evolved serving mobile location center, E-SMLC, of the wireless device; and   send, upon fulfilment of a criterion relating to the indication of the wireless device, a LCS-AP location abort request message to the E-SMLC.   
     
     
         27 . (canceled)