Question: In E-UTRAN, which of the following Terrestrial Beacon Systems (TBS) positioning modes relies solely on the User Equipment (UE) for both measurements and location calculation, without any assistance from the network?
Option 1: UE-Assisted
Option 2: UE-Based with Network Validation
Option 3: Standalone
Option 4: Hybrid TBS Mode
Explanation: The correct answer is Option 3 (Standalone) because, as defined in the E-UTRAN specification for TBS positioning methods, "Standalone" mode is characterized by the UE performing TBS measurements and calculating its own location without any assistance from the network, potentially leveraging additional non-TBS sources. This distinguishes it from UE-Assisted (which involves sending measurements to the network for position calculation) and UE-Based modes that may still utilize network assistance in some capacity. The "Hybrid TBS Mode" is not a recognized mode within the provided context, making Option 3 the accurate choice.