Question: What primary factors influence a User Equipment (UE) transmitter's decision to adjust its uplink output power in a TDD system, as per 3GPP specifications?
Option 1: Measured downlink path loss, values from higher layer signalling, and a path loss weighting parameter.
Option 2: UE's battery life, current network congestion, and the type of data being transmitted.
Option 3: Signal-to-Noise Ratio (SNR) of the uplink channel, UE's velocity, and time of day.
Option 4: Downlink transmission power, uplink channel bandwidth, and UE's operating temperature.
Explanation: In a TDD (Time Division Duplex) system, uplink power control is crucial for efficient communication. The correct answer reflects the key factors influencing this control: - Measured downlink path loss helps estimate the uplink path loss due to the reciprocal nature of wireless channels in TDD. - Values determined by higher layer signalling provide network-specific adjustments based on overall system conditions. - Path loss weighting parameter, as defined in relevant 3GPP specifications (e.g., TS 25.331), fine-tunes these adjustments for optimal performance. These factors work together to set the UE's output power, defined as the RRC filtered mean power of the transmit timeslot, ensuring effective and controlled uplink transmission.