Uplink Interference Handling with Adaptive Waveform and Power Control
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Solution Overview
Problem
Modern wireless communication standards face challenges with uplink interference due to non-linearities in transmitter devices, leading to signal spectral regrowth and interference with adjacent channels, which are exacerbated by high Peak-to-Average Power Ratio (PAPR) in OFDMA signals, causing inefficiencies and increased power consumption.
Innovation Solution
An apparatus and method that define different prioritized frequency layouts for uplink signal interference handling, verify appropriate radio conditions for reference signal waveform emission and power class boosting, and initiate signaling to redirect uplink service traffic to minimize interference by optimizing power back-off and amplifier class.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If highly linear power amplifier properties are used to avoid interference with adjacent channels, then uplink interference is reduced, but device complexity and power consumption increase
Solution Approach 1:
The system dynamically switches between different uplink reference signal waveforms (CP-OFDM and DFT-s-OFDM) based on radio conditions and interference levels. This dynamic adaptation allows the system to use highly linear DFT-s-OFDM waveforms only when interference is problematic, while using more complex CP-OFDM waveforms when linearity requirements are less stringent, thus resolving the contradiction between interference reduction and device complexity
Solution Approach 2:
The system changes the waveform parameter (spectral shape) based on operating conditions. By selecting between different waveform types with different spectral characteristics, the system can optimize linearity performance when needed without permanently committing to the complexity of highly linear amplifier designs, thereby reducing the overall device complexity while maintaining interference mitigation capability
2Object-affected harmful factors
If highly linear power amplifier properties are used to avoid interference with adjacent channels, then uplink interference is reduced, but power consumption increases
Solution Approach 1:
The system dynamically selects waveform types based on real-time radio conditions and interference measurements. By using DFT-s-OFDM waveforms with highly linear PAs only when interference thresholds are exceeded, the system avoids continuous operation in high-linearity mode, thereby reducing overall power consumption while maintaining interference mitigation when necessary
Solution Approach 2:
The system changes the spectral shape parameter of the uplink reference signal based on interference conditions. This parameter change allows the system to achieve acceptable linearity performance with lower power consumption by using CP-OFDM waveforms when interference is not critical, reserving the power-intensive highly linear mode only when needed
3Use of energy by moving object
If spectral shaping filtering is used to reduce PAPR, then power amplifier efficiency improves, but spectral efficiency deteriorates due to excess bandwidth
Solution Approach 1:
The system dynamically switches between CP-OFDM and DFT-s-OFDM waveforms based on radio conditions. When spectral efficiency is critical and interference is low, the system uses CP-OFDM without spectral shaping, maintaining high spectral efficiency. When interference becomes problematic, it switches to DFT-s-OFDM with spectral shaping, accepting the bandwidth overhead to achieve better PA efficiency and lower interference
Solution Approach 2:
The system changes the spectral shape parameter of the uplink waveform based on interference measurements. By adjusting this parameter dynamically, the system can optimize the trade-off between spectral efficiency and power amplifier efficiency according to current network conditions, rather than being fixed to one waveform type
4Reliability
If Pi/2-BPSK modulation with spectral shaping is used, then PAPR is reduced and coverage is improved, but spectral efficiency is reduced due to excess bandwidth
Solution Approach 1:
The system dynamically selects between different modulation and waveform combinations based on radio conditions and interference levels. In cell-edge scenarios with high interference, it uses Pi/2-BPSK with spectral shaping to improve coverage and reduce PAPR. In better conditions, it switches to more spectrally efficient modulations without spectral shaping, thus dynamically optimizing the coverage-spectral efficiency trade-off
Data Source
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AI summary
An apparatus is disclosed, comprising at least one processor, and at least one memory storing instructions that, when executed by the at least one processor, cause the apparatus at least to define (301) different prioritized frequency layouts for uplink signal interference handling, verify (302) first radio conditions for enabling most appropriate uplink reference signal waveform emission, verify (303) second radio conditions for signalling lower allowed uplink power back-off and uplink maximum output power class boosting, and, based on the verifying, initiate (304) signalling to mitigate uplink signal interference by redirecting uplink service traffic to a most appropriate prioritized frequency layout.