location measurement unit (UMTS) (LMU)
As can be seen from the name Location Measurement Unit (LMU), this is a unit for determining the position of mobile devices in mobile communications networks.
LMUs are units of the base station, Node B, and are used in GSM and UMTS networks to locate or measure the propagation time between the mobile device and the base stations. From the propagation time, they determine the geographical position of the mobile stations using the known coordinate values of the base stations.
The position of the mobile device is determined using propagation time measurements such as Enhanced Observed Time Difference( E-OTD), which is used in GSM networks, or Observed Time Difference of Arrival( OTDoA) from UMTS.