OTDOA testing | OTDOA conformance testing and equipments

This page describes OTDOA testing and OTDOA test cases and mentions OTDOA conformance testing. It mentions OTDOA test equipments used for OTDOA measurements. The test equipment vendors include Spirent communications, Rohde and Schwarz etc.

About OTDOA:
The term OTDOA stands for Observed Time Difference of Arrival. It is one of the positioning technique used in LTE compliant mobile phones. This technique is used to determine location of UE (mobile phone) in emergency situations. It works very effectively and accurately irrespective of UE positions such as indoors, on tall buildings and even in forest locations surrounded by dense trees. This is due to the fact that LTE signals penetrate steel and concrete structures as well as trees. Moreover LTE has introduced special reference signal referred as PRS ("Positioning Reference Signal") to provide better estimation performance to locate the UE. It is similar to E-OTD (Enhanced Observed Time Difference) used in WCDMA and AFTL (Advanced Forward Link Trilateration) used in CDMA for location determination.

There are two main types of OTDOA viz. downlink and uplink.
➨In downlink OTDOA, UE receives the downlink signals from serving eNB and multiple neighbour eNBs and determines RSTD (Reference Signal Time Difference). This information is fed back to the network (i.e. eNBs) by UE. Based on the RSTD information eNBs determine position of the UE.
➨In uplink OTDOA, eNBs receives the uplink transmissions from the UE and determines its position.

The OTDOA conformance test cases are defined in 3GPP TS 37.571 release document. Following table mentions OTDOA test equipment vendors with their offerings.
Refer OTDOA basics and working >>.

The OTDOA testing involves test cases in the following areas:
• Conformance test specification
• Operator acceptance testing
• R & D performance testing

OTDOA test equipments

Following are the OTDOA test equipments used for OTDOA measurements.

OTDOA test equipment Description
CS8 interactive tester from Spirent It is a network emulator which allows UE to connect with eNB as in realtime network scenario. It allows whether mobile gets registered with eNB(i.e. network) and whether it is sensing the PRS (Positioning Reference Signal) transmitted by eNBs and so on. This OTDOA equipment allows to conduct initial level of OTDOA testing of the UE. It is used for manual OTDOA testing. It allows to configure eNBs and PRS configurations.
8100 LTS from Spirent This LTE Location Technology Solution is designed for automated testing of OTDOA feature in a mobile phone.It is second level of testing which allows testing in three different modes as mentioned above. This testdrive LTS provides test cases as per TS 37.571 readily available to test the UE. These test cases can also be modified and configured. The GUI of testDrive LTS allows user to review all the messages exchanged between UE and eNBs.
TS-LBS Location Based Services Test System from Rohde and Schwarz It supports all positioning technologies viz. A-GNSS, OTDOA, eCID and hybrid technologies. It supports technologies such as LTE FDD, LTE TDD, GERAN, HSPA, WCDMA, etc.


U-TDOA vs GPS  Basics of OTDOA and its working  OTDOA vs U-TDOA  GPS vs GLONASS  GPS vs AGPS  GPS vs GPRS  GPS Frame Structure  GPS Basics Tutorial  GPS Antenna  GPS Receiver Module  GPS Satellite  GPS Tracking System 

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