Power Back-Off for 256 QAM Downlink Signal Quality
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Solution Overview
Problem
High-order modulation schemes like 256 QAM in wireless communication systems face performance deterioration due to self-interference and errors caused by non-linearity in power amplifiers, leading to reduced signal-to-noise-plus-interference ratio (SINR) and error vector magnitude (EVM), especially in small cell environments.
Innovation Solution
Implementing a power back-off scheme that reduces transmission power to maintain low EVM and improve SINR, specifically by configuring power reduction for resources allocated to terminals using 256 QAM, and signaling this configuration to user equipment (UE) through high-layer signaling.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If high order modulation scheme (256 QAM) is introduced to improve spectral efficiency, then data transmission rate is improved, but performance deterioration occurs due to self interference and power amplifier non-linearity
Solution Approach 1:
The patent changes the transmission power parameter by applying power back-off specifically for 256 QAM modulated signals. This reduces the peak-to-average power ratio and minimizes the impact of power amplifier non-linearity, thereby improving EVM and signal quality while maintaining the use of high-order modulation for spectral efficiency
2Reliability
If transmission power is increased to improve signal quality, then SINR is improved, but self interference and EVM increase due to power amplifier non-linearity
Solution Approach 1:
The patent applies power back-off to reduce transmission power for 256 QAM signals, which decreases the operating point of the power amplifier into a more linear region. This reduces self-interference and EVM while maintaining acceptable signal quality through optimized power levels
3Reliability
If power back-off is applied to reduce EVM and improve SINR, then signal quality is improved, but transmission power is reduced
Solution Approach 1:
The patent applies power back-off selectively only to resources allocated for 256 QAM modulation, while other modulation schemes operate at normal power levels. This localized application maintains EVM performance for high-order modulation without unnecessarily reducing overall transmission power
4Productivity
If 256 QAM is used to improve spectral efficiency, then data rate is improved, but hardware implementation complexity increases due to stricter EVM requirements
Solution Approach 1:
The patent modifies the transmission power parameter through power back-off to relax EVM requirements for 256 QAM. This allows existing hardware implementations to achieve the required performance without needing more complex or higher-cost components
Data Source
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AI summary
One disclosure of the present application provides a method for receiving downlink data in a wireless communication system supporting 256 QAM. The method for receiving downlink data in a wireless communication system supporting 256 QAM comprises the steps of: receiving setting information for power back-off; receiving downlink data transmitted on the basis of the setting information for power back-off; and demodulating the downlink data received on the basis of the setting information for power back-off, wherein the setting information for power back-off is information related to at least one of whether to apply the power back-off, a reduced amount of power of the downlink data by the power back-off, a frame index to which the power back-off is applied, a subframe index and a resource to which the power back-off is applied.