Chapter 4 FortiOS Carrier : GTP identity filtering : Other identity and location based information elements : Access Point Number (APN) : User Location Information (ULI)
  
User Location Information (ULI)
Gives Cell Global Identity/Service Area Identity (CGI/SAI) of where the mobile station is currently located. The ULI and the RAI are commonly used together to identify the location of the mobile device.
ULI is part of advanced filtering configuration. See “Configuring advanced filtering in FortiOS Carrier”.