Uplink Power Control for Multiplexed OFDM Symbols
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Solution Overview
Problem
In 5G New Radio (NR) systems, the peak-to-average power ratio (PAPR) of OFDM symbols multiplexed by a reference signal (RS) and a channel is higher than those not multiplexed, leading to performance issues for power-limited terminals, as they cannot transmit data effectively due to reduced transmit power across all symbols.
Innovation Solution
A method where a terminal determines the waveform used based on downlink signaling, calculates the power difference between symbols multiplexed and not multiplexed by an RS, and adjusts the uplink transmit power accordingly to reduce PAPR, optimizing power usage for power-limited terminals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If power back-off method is used to meet peak power transmit requirement, then PAPR requirement is satisfied, but transmit power of remaining symbols not multiplexed by RS is reduced causing performance loss
Solution Approach 1:
The patent applies local quality by differentiating power control treatment between multiplexed and non-multiplexed OFDM symbols. Specifically, power back-off is applied only to symbols containing both reference signals and data (multiplexed symbols), while non-multiplexed symbols maintain their original power levels. This selective approach resolves the contradiction by satisfying peak power requirements locally where needed without degrading overall transmission performance.
Solution Approach 2:
The patent segments OFDM symbols into two categories: multiplexed symbols (containing both RS and channel data) and non-multiplexed symbols. By segmenting the power control application, the system can apply different power strategies to different symbol types, ensuring peak power compliance for multiplexed symbols while preserving full power transmission for non-multiplexed symbols, thus eliminating the performance loss.
2Reliability
If transmit power is reduced on target time-frequency resources, then PAPR of multiplexed OFDM symbol is reduced, but transmit power for data transmission is compromised
Solution Approach 1:
The patent implements local quality by applying power reduction specifically to the reference signal components within multiplexed symbols, while preserving the power level of data components in both multiplexed and non-multiplexed symbols. This targeted approach reduces PAPR caused by RS-channel multiplexing without compromising the transmit power available for actual data transmission.
Solution Approach 2:
The patent segments the uplink signal into reference signal components and data components, applying power control differently to each. By segmenting the power adjustment at the component level rather than symbol level, the system achieves PAPR control for multiplexed symbols while maintaining adequate transmit power for data transmission.
3Adaptability or versatility
If consistent pilot design is used for both CP-OFDM and DFT-s-OFDM waveforms, then multiplexing between RS and channel is supported, but PAPR of multiplexed symbols becomes higher
Solution Approach 1:
The patent applies local quality by implementing waveform-specific power control parameters. While both CP-OFDM and DFT-s-OFDM waveforms use the same pilot design for multiplexing compatibility, the system applies different power back-off values tailored to each waveform's characteristics. This allows maintaining adaptability across waveform types while addressing their respective PAPR concerns through localized parameter adjustment.
Solution Approach 2:
The patent employs parameter changes by introducing waveform-dependent power control parameters. The base station configures different power back-off values based on the selected waveform (CP-OFDM or DFT-s-OFDM), allowing the system to maintain consistent pilot design for multiplexing support while adjusting power parameters to optimize PAPR performance for each specific waveform type.
Data Source
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AI summary
The present invention discloses an uplink signal sending method and receiving method, a terminal, and a base station. The method includes: receiving, by a terminal, downlink signaling delivered by a base station, and determining, based on the downlink signaling, a waveform used by the terminal; determining, by the terminal based on a correspondence between a waveform and a power difference, a power difference corresponding to a target time-frequency resource; determining, based on the determined power difference, an uplink transmit power of an uplink signal that is mapped on the target time-frequency resource, and sending the uplink signal by using the power. The target time-frequency resource refers to an OFDM symbol multiplexed by an RS and a channel, or may be an RE that is used for mapping a channel and that is in an OFDM symbol multiplexed by an RS and a channel. In embodiments, a transmit power of the uplink signal on the target time-frequency resource is reduced to reduce the OFDM symbol multiplexed by an RS and a channel, so that a power-limited terminal can also normally send data, thereby optimizing use of a transmit power of the power-limited terminal.