Question: In the context of HSDPA (High-Speed Downlink Packet Access) testing, as outlined in the procedure for measuring UE (User Equipment) power, what is the primary purpose of sending a HS-SCCH (High-Speed Shared Control Channel) order to activate UL_CLTD (Uplink Closed Loop Transmit Diversity) activation state 3?
Option 1: To initiate a handover to a different cell to improve signal strength.
Option 2: To activate a feature that enhances downlink data transmission rates by adjusting UE transmit power.
Option 3: To trigger a change in the UE's receiver sensitivity for better uplink communication.
Option 4: To start a diagnostic test for identifying issues with the UE's antenna configuration.
Explanation: Activating UL_CLTD (Uplink Closed Loop Transmit Diversity) activation state 3, via a HS-SCCH order, is primarily aimed at enhancing the uplink transmission by dynamically adjusting the UE's transmit power based on feedback from the network. This closed-loop mechanism improves the overall efficiency and quality of the uplink communication, which indirectly supports the downlink data transmission rates by ensuring more reliable and efficient use of the uplink channel for acknowledgments and control signals. Thus, it is closely related to enhancing downlink data transmission rates through better management of UE transmit power in response to network conditions.