2-Step RACH Power Control Using PRACH Preamble Reference
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Solution Overview
Problem
Current wireless communication systems face challenges in efficiently implementing power control during the 2-step random access channel (RACH) procedure, particularly in determining optimal transmission powers for PRACH and PUSCH to ensure reliable connection establishment with low latency and support for machine-type communications.
Innovation Solution
The method involves determining a first transmission power for the PRACH preamble and a second transmission power for the PUSCH transmission, with the latter based on the former, and applying power offsets or ramping mechanisms to adjust transmission powers according to bandwidth allocations and higher-layer signaling, ensuring effective power control for MsgA transmission in the 2-step RACH procedure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If transmission power for PUSCH is determined independently of PRACH power, then power control flexibility is improved, but power management complexity and access latency increase
Solution Approach 1:
The patent applies preliminary action by determining the PUSCH transmission power based on the PRACH preamble power before the actual transmission. The UE calculates the PUSCH power using the PRACH power as a reference, applying power offsets and adjustments in advance. This preliminary power determination simplifies the overall power management while maintaining flexibility, as the PUSCH power is derived from the already-determined PRACH power rather than being independently controlled.
2Reliability
If power ramping is applied to both PRACH and PUSCH with different step sizes, then connection establishment reliability is improved, but power control complexity increases
Solution Approach 1:
The patent applies local quality by implementing different power ramping step sizes for PRACH and PUSCH transmissions. Specifically, the PRACH preamble uses one power ramping step size while the PUSCH transmission uses a different power ramping step size. This allows each transmission type to be optimized independently for its specific requirements, improving connection establishment reliability while managing power control complexity through targeted differentiation rather than uniform control.
3Reliability
If MsgA transmission uses higher power to ensure reliable detection, then connection establishment reliability is improved, but energy consumption increases
Solution Approach 1:
The patent applies feedback by using the PRACH preamble transmission power as a reference to determine the PUSCH transmission power. The UE monitors the outcome of its transmissions and adjusts subsequent power levels based on this feedback loop. The PUSCH power is calculated using the PRACH power plus applicable offsets and adjustments, creating a feedback-driven power control mechanism that ensures reliable detection while optimizing energy consumption based on actual transmission conditions.
Data Source
AI summary
A user equipment (UE) implementing power control for a 2-step random access channel (RACH) procedure is provided. The UE determines a first transmission power of a physical random access channel (PRACH) preamble to be used during a 2-step RACH procedure. The UE determines a second transmission power of a physical uplink shared channel (PUSCH) transmission to be used during the 2-step RACH procedure based on the first transmission power of the PRACH preamble. The UE then performs the 2-step RACH procedure based on the first transmission power of the PRACH preamble and the second transmission power of the PUSCH transmission. The UE switches to a 4-step RACH procedure from the 2-step RACH procedure based on a determination that the PRACH preamble was successfully detected and the PUSCH transmission was falsely detected, and performs the 4-step RACH procedure based on the first transmission power of the PRACH preamble.