Observed time difference of arrival angle of arrival discriminator

Abstract

A method, user equipment (UE) and location server for estimating position of a UE based on observed angles of arrival. According to one embodiment, angles of arrival of signals from a plurality of base stations are received by a UE are observed by scanning for position reference signals (PRS) by adjusting a phase difference between antennas to cause a null of a beam of the UE to be incremented through an angular sector. For each of a plurality of base stations, an angle of arrival at which the null is steered when a PRS is suppressed by the null and a reference signal time difference, RSTD, are determined. Each angle of arrival and corresponding RSTD is transmitted to a location server which estimates UE position based on the observed angles of arrival. Further, the location server may instruct the UE to suppress a non-line-of-sight PRS signal.

1 - 23 . (canceled) 
     
     
         24 . A method performed by a user equipment (UE), the method comprising:
 scanning for position reference signals (PRSs) from a plurality of base stations, by adjusting a phase difference between antennas to cause a null of a beam of an antenna pattern of the UE to be incremented through an angular sector;   determining, for each of the plurality of base stations:
 an observed angle of arrival (AOA) at which the null is steered when a PRS is suppressed by the null; and 
 a reference signal time difference (RSTD); and 
   transmitting each observed AOA and corresponding RSTD to a location server.   
     
     
         25 . The method of  claim 24 , further comprising determining a spatial orientation of the UE to determine a reference plane for the scanning. 
     
     
         26 . The method of  claim 24 , further comprising receiving from the location server an indication of a target PRS to be suppressed, the target PRS being determined to be received from a non-line-of-sight direction. 
     
     
         27 . The method of  claim 26 , wherein the indication includes a target AOA at which the target PRS is received, and the method further comprises steering a null to the target AOA. 
     
     
         28 . The method of  claim 27 , wherein the target AOA differs, from the observed AOA corresponding to the target PRS, by more than a threshold. 
     
     
         29 . The method of  claim 24 , further comprising:
 for a first PRS received from one of the plurality of base stations, scanning the null to determine if more than one minimum of the first PRS is encountered, the more than one minimum indicating that the first PRS is received via multiple paths.   
     
     
         30 . A user equipment (UE), comprising:
 a plurality of antennas;   a phase shifter configured to adjust a relative phase between at least two of the plurality of antennas;   a transceiver configured to receive and process signals from the plurality of antennas, the signals including at least one position reference signal (PRS);   a memory storing instructions; and   a processor configured to execute the instructions to:
 scan for PRSs from a plurality of base stations, by controlling the phase shifter to adjust a phase difference between antennas to cause a null of a beam of an antenna pattern of the UE to be incremented through an angular sector; 
 determine, for each of the plurality of base stations:
 an observed angle of arrival (AOA) at which the null is steered when a PRS is suppressed by the null; and 
 a reference signal time difference (RSTD); and 
 
 transmit each observed AOA and corresponding RSTD to a location server. 
   
     
     
         31 . The UE of  claim 30 , wherein the processor is further configured to execute the instructions to:
 determine a spatial orientation of the UE to determine a reference plane for the scanning.   
     
     
         32 . The UE of  claim 30 , wherein the processor is further configured to execute the instructions to:
 receive from the location server an indication of a target PRS to be suppressed, the target PRS being determined to be received from a non-line-of-sight direction.   
     
     
         33 . The UE of  claim 32 , wherein the indication includes a target AOA at which the target PRS is received, and the processor is further configured to execute the instructions to steer a null to the target AOA. 
     
     
         34 . The UE of  claim 33 , wherein the target AOA differs, from the observed AOA corresponding to the target PRS, by more than a threshold. 
     
     
         35 . The UE of  claim 30 , wherein the processor is further configured to execute the instructions to:
 for a first PRS received from one of the plurality of base stations, scan the null to determine if more than one minimum of the first PRS is encountered, the more than one minimum indicating that the first PRS is received via multiple paths.   
     
     
         36 . A non-transitory computer-readable medium storing a program code executable by a user equipment (UE), wherein the execution of the program code causes the UE to perform operations comprising:
 scanning for position reference signals (PRSs) from a plurality of base stations, by adjusting a phase difference between antennas to cause a null of a beam of an antenna pattern of the UE to be incremented through an angular sector;   determining, for each of the plurality of base stations:
 an observed angle of arrival (AOA) at which the null is steered when a PRS is suppressed by the null; and 
 a reference signal time difference (RSTD); and 
   transmitting each observed AOA and corresponding RSTD to a location server.   
     
     
         37 . The non-transitory computer-readable medium of  claim 36 , wherein the operations further comprise:
 determining a spatial orientation of the UE to determine a reference plane for the scanning.   
     
     
         38 . The non-transitory computer-readable medium of  claim 36 , wherein the operations further comprise:
 receiving from the location server an indication of a target PRS to be suppressed, the target PRS being determined to be received from a non-line-of-sight direction.   
     
     
         39 . The non-transitory computer-readable medium of  claim 38 , wherein the indication includes a target AOA at which the target PRS is received, and the operations further comprise steering a null to the target AOA. 
     
     
         40 . The non-transitory computer-readable medium of  claim 39 , wherein the target AOA differs, from the observed AOA corresponding to the target PRS, by more than a threshold. 
     
     
         41 . The non-transitory computer-readable medium of  claim 36 , wherein the operations further comprise:
 for a first PRS received from one of the plurality of base stations, scanning the null to determine if more than one minimum of the first PRS is encountered, the more than one minimum indicating that the first PRS is received via multiple paths.