Uplink Power Control for PRACH and PUSCH Overlap
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Solution Overview
Problem
In LTE-A Rel-11, the concurrent transmission of PRACH with PUCCH/PUSCH signals leads to uplink power control challenges, as existing methods fail to ensure that the total transmit power does not exceed the maximum allowed power of the UE, especially when PRACH overlaps with other uplink signals.
Innovation Solution
The proposed uplink power control method involves determining the target transmit power of uplink signals and PRACH, and if the sum exceeds the maximum power, maintaining the PRACH power unchanged while scaling down SC-FDMA symbols of other uplink signals to prevent power exceeding the UE's maximum capacity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If PRACH is transmitted concurrently with PUCCH/PUSCH signals, then random access function is achieved, but total transmit power exceeds maximum allowed power of UE
Solution Approach 1:
The patent extracts the PRACH transmission from the power control calculation by determining its target power separately and excluding it from the total power sum used for scaling decisions. This allows PRACH to maintain its required power level while other uplink signals are scaled down to comply with maximum power constraints.
Solution Approach 2:
The patent applies different power control treatments to different signal types: PRACH signals are excluded from power-based scaling decisions, while PUCCH and PUSCH signals are subject to power scaling. This localized differentiation ensures random access reliability while managing overall power consumption.
2Productivity
If target transmit power of all uplink signals is determined, then normal uplink transmission is achieved, but concurrent transmission with PRACH causes power exceeding maximum capacity
Solution Approach 1:
The patent performs preliminary determination of PRACH target transmit power before incorporating it into the overall power control decision. By establishing PRACH power requirements in advance and excluding them from the total power calculation, the system can proceed with normal uplink transmission planning while avoiding power overflow issues.
Solution Approach 2:
The patent segments the power control process into separate handling for PRACH signals and other uplink signals. PRACH power is determined independently and excluded from the total power sum, while PUCCH and PUSCH powers are calculated and scaled separately, allowing each signal type to be optimized according to its specific requirements.
Data Source
AI summary
Disclosed are a method and user equipment of uplink power control. The method comprises the steps of: UE determines the target transmission power of uplink signal which transmitted on each synchronization uplink component carrier of current uplink sub-frame; Judging whether PRACH transmission exists on uplink secondary component carrier of current uplink sub-frame; If judged that there is, determining the PRACH target transmission power, and further judging that whether the sum of the uplink signal power and the PRACH target transmission power exceeds the maximum transmission power of UE; If judged exceeded, holding the PRACH target transmission power constant, and reducing the target transmission power of all or part of SC-FDMA symbol of uplink signal which is contained in current uplink sub-frame and needed to reduce power. The technical scheme of present invention is using for uplink power control when PRACH signal is overlap with other uplink signal.