Selective Uplink Digital Pre-Distortion for ACLR Control
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Solution Overview
Problem
Power amplifiers in communication networks introduce distortion, particularly out-of-band emission, which is challenging to mitigate without increasing hardware complexity and power consumption, especially in lower frequency ranges like FR1 and FR3, where beamforming techniques are not practical.
Innovation Solution
A mechanism for user devices to transmit reference signals without digital pre-distortion, allowing network devices to determine if DPD is needed, enabling dynamic activation or deactivation based on ACLR violations, thus optimizing uplink transmissions and reducing power consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If digital pre-distortion is used to reduce out-of-band emission, then ACLR performance is improved, but device complexity and power consumption increase
Solution Approach 1:
The patent implements dynamic activation and deactivation of digital pre-distortion based on real-time channel conditions and power amplifier characteristics. The network device determines whether to activate DPD for a given user device based on measured ACLR and other parameters, allowing the system to adapt between using DPD (when needed) and not using it (when unnecessary), thus reducing average complexity and power consumption while maintaining performance when required
2Object-generated harmful factors
If digital pre-distortion is used to reduce out-of-band emission, then ACLR performance is improved, but power consumption increases
Solution Approach 1:
The system dynamically adjusts DPD activation status based on measured performance parameters. When the power amplifier operates in conditions where distortion is significant, DPD is activated to control out-of-band emission. When the PA operates in linear regions or under different conditions, DPD is deactivated, reducing power consumption. This dynamic approach ensures DPD is only used when necessary to meet ACLR requirements
3Manufacturing precision
If digital pre-distortion is used to reduce in-band distortion, then EVM performance is improved, but device complexity increases
Solution Approach 1:
The patent applies dynamic activation of digital pre-distortion based on real-time assessment of channel conditions and power amplifier characteristics. The network device measures performance parameters and determines whether to activate DPD for each user device, enabling the system to use DPD only when in-band distortion is significant, thereby reducing average device complexity while maintaining EVM performance when needed
4Object-generated harmful factors
If beamforming techniques are used to relax out-of-band emission requirements, then ACLR performance is improved, but applicability is limited to higher frequency ranges
Solution Approach 1:
The patent changes the approach to out-of-band emission control based on frequency range parameters. For higher frequency ranges (FR2 and above), beamforming techniques are used to relax ACLR requirements. For lower frequency ranges (FR1 and lower FR3), where beamforming is not practical, the system instead uses digital pre-distortion at the user device to control out-of-band emission. This parameter-based differentiation allows the system to adapt to different frequency characteristics and apply the most suitable mitigation technique for each range
Data Source
AI summary
This specification describes methods, apparatus, and/or computer programs for selectively utilizing digital pre-distortion in a communication network. According to a first aspect of this specification, there is described a user device including means for transmitting an uplink reference signal to a network device without using digital pre-distortion; means for receiving, from a network device, an indication indicating whether digital pre-distortion is enabled or disabled for performance, by the user device, of subsequent uplink transmissions, wherein the transmitted uplink reference signal is useable for determination of the indication; and means for, when the indication indicates that digital pre-distortion is enabled for performance of subsequent uplink transmissions, performing one or more uplink transmissions using digital pre-distortion, and when the indication indicates that digital pre-distortion is disabled for performance of subsequent uplink transmissions, performing one or more uplink transmissions without using digital pre-distortion.