Question: In UTRAN Iub interface Node B Application Part (NBAP) signalling for 1.28Mcps TDD, which midamble allocation scheme allows for explicit assignment for both Downlink (DL) and Uplink (UL) and is specific to each User Equipment (UE)?
Option 1: Default Midamble - Allocated by Layer 1 based on channelisation code for both DL and UL
Option 2: Common Midamble - Determined by the number of channelisation codes, applicable to DL only
Option 3: UE Specific Midamble - Explicitly assigned midamble for each UE, applicable to both DL and UL
Option 4: Hybrid Midamble - A combination of Default and Common midambles for DL and UL respectively
Explanation: The correct answer is Option 3 because the question specifically asks for a scheme that allows explicit assignment for each UE and applies to both Downlink (DL) and Uplink (UL). Only "UE Specific Midamble" meets these criteria by being explicitly assigned on a per-UE basis for both DL and UL, unlike the other options which either don't apply to both directions or aren't explicitly assigned per UE.