Question: In Evolved Universal Terrestrial Radio Access Network (E-UTRAN), which two deployment scenarios have been identified as challenging for conventional Inter-Cell Interference Coordination (ICIC) techniques to mitigate co-channel interference?
Option 1: Macro Cell and Femto Cell Scenarios
Option 2: Rural Deployment and Highway Deployment Scenarios
Option 3: Indoor Small Cell and Outdoor Macro Cell Scenarios
Option 4: Closed Subscriber Group (CSG) Scenario and Pico Cell Scenario
Explanation: The Closed Subscriber Group (CSG) Scenario, involving restricted access cells, and the Pico Cell Scenario, characterized by small cells within a larger macro cell footprint, are particularly prone to co-channel interference issues, making them the identified challenging scenarios for conventional ICIC techniques.