OTDOA, or Observed Time Difference of Arrival, is a protocol that uses cell towers to measure the time it takes for an LTE signal to reach a tower to determine a phone's location, as explained by (http://www.androidauthority.com/oneplus-5-911-rebooting-issue-explained-789822/) Android Authority .
The OnePlus 5 911 rebooting problem is caused by a memory bug that's triggered when OTDOA information is being obtained and sent out.
This is because not all emergency numbers support the OTDOA protocol.
In addition, Rohde & Schwarz announced that CETECOM, a specialist in test and certification for wireless communications devices, has selected the R&S TS8980FTA-2 and R&S CMW500 wireless test platforms for conformance and network-operators acceptance testing for LTE RIO CA, IMS, VoLTE, RCS, E911 over IMS, A-GNSS, OTDOA, and eCID.
Both organizations will use the platforms to support technologies such as CA, VoLTE/IMS, RCS, A-GNSS, OTDOA, eCID, and E911 over IMS.
Inside the Method country suburban city buildings Cell ID 1-35km 1-10km 50m-lkm 50m-lkm Cell ID +TA 1-35km 1-10km 50m-lkm 50m-lkm U-TDOA OTDOA
80m 50m 50m 50m E-OTD 50-150m 50-150m 50-150m 50-150m A-GPS 30m 40m 30-150m 200m
The Time of Arrival (TOA), OTDOA, as well its enhancements, such as cumulative virtual blanking, are affected in a similar fashion although this may have more of an impact as these methods are meant to deliver greater accuracy than the Cell ID based methods .
Some methods require more human intervention to set up, such as PCM and probabilistic fingerprint matching, whilst others might require additional hardware, such as OTDOA requiring location measurement units.
Even though OTDOA-IPDL improves OTDOA availability, it is still hard to obtain measurements from at least four cells in a UMTS network.
A further improvement to OTDOA was proposed by 3GPP, which is the introduction of positioning elements (PEs) that transmit short three-symbol identifier codes during Node B idle periods.
In LTE, current standards support Observed Time Difference of Arrival (OTDOA), an advanced cellular positioning technology that can augment A-GNSS and provide a more accurate location fix for indoor scenarios.
As the leader in location technology testing, Spirent is currently working with all the key industry players to evaluate OTDOA and its integration with other positioning technologies, and to enable operators to meet the location requirements for VoLTE E911 and the evolving FCC requirements.