UE Initial Transmit Power Adjustment for Carrier Frequency Handovers
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Solution Overview
Problem
In cellular wireless communication, user equipment (UE) faces challenges in quickly determining a suitable transmission power when transitioning from one base station to another operating on a different carrier frequency, which can lead to communication failures if the UE does not reach a suitable power level quickly enough.
Innovation Solution
The UE determines a baseline initial transmit power based on previous communications with a first base station and adjusts it based on the difference between the old and new carrier frequencies, as well as the distance between the UE and the base stations, to establish an adjusted initial transmit power for communication with the new base station.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the UE uses a standard power control process to determine transmission power when transitioning to a new base station on a different carrier frequency, then the power control process will eventually reach a suitable power level, but it will take too much time and may lead to communication failures
Solution Approach 1:
The patent applies preliminary action by having the UE determine an initial transmit power level before actually transitioning to the new base station on the new carrier frequency. The UE calculates this initial power based on previous communication parameters (from the old carrier frequency) and anticipated conditions (new carrier frequency characteristics, distance to new base station). This pre-calculation allows the UE to start transmission immediately at a suitable power level, avoiding the time-consuming iterative power control process that would otherwise be required after connection establishment.
Solution Approach 2:
The patent applies beforehand cushioning by incorporating margin adjustments to the calculated initial transmit power. The system anticipates potential power deficiencies or excesses by adding cushioning factors based on the carrier frequency difference and distance variations. This pre-built cushion ensures that even if the initial calculation is not perfectly accurate, the UE starts with a power level that is sufficiently close to the optimal value, reducing the need for subsequent power adjustments and minimizing communication failures.
2Speed
If the UE determines initial transmit power based on previous communications, then the UE can quickly establish communication, but the accuracy may be insufficient when carrier frequencies differ significantly
Solution Approach 1:
The patent applies parameter changes by systematically adjusting the initial transmit power calculation based on multiple parameters including the difference between old and new carrier frequencies, the distance to the new base station, and the received power level from the new base station. The formula incorporates these parameters to dynamically calculate an appropriate initial power level: P_new = P_old + adjustment_factors. This multi-parameter approach maintains both speed and accuracy by adapting the power calculation to the specific conditions of each frequency transition scenario.
Solution Approach 2:
The patent applies feedback by using the received power level measurement from the new base station to refine the initial transmit power determination. After the UE transmits at the calculated initial power, the new base station measures the received signal strength and provides feedback (power control commands) to the UE. This feedback loop allows the system to quickly converge to the optimal power level, combining the speed of initial estimation with the precision of measured feedback.
Data Source
AI summary
A method and corresponding system to help manage user equipment device (UE) transmission power, specifically in a scenario where the UE was being served by a base station on a first carrier frequency and the UE is then going to communicate with a base station (whether the same or another base station) instead on a second, different carrier frequency. As disclosed, a UE may determine, based on communication by the UE on the first carrier frequency, a baseline initial transmit power for the UE to use for an initial transmission from the UE to a cellular base station on the second carrier frequency. Responsive to the second carrier frequency being different than the first carrier frequency, the UE may adjust the baseline initial transmit power to establish an adjusted initial transmit power. The UE may then engage in the initial transmission using the adjusted baseline initial transmit power.