AF Repeater Impairment Correction Using Base Station DPD Feedback
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Wireless communication networks, particularly those using amplify-and-forward repeaters, face performance degradation due to timing restrictions, link budget limitations, distortion, droop, internal and external interference, and the lack of digital pre-distortion and pre-equalization capabilities, which hinder efficient signal amplification and interference mitigation.
Innovation Solution
Implementing a method for base stations to perform digital pre-distortion and pre-equalization at amplify-and-forward repeaters based on measured non-linear and droop characteristics, and providing exclusion indications for resources allocated by base stations to avoid or mitigate interference experienced by repeaters, through training sessions and feedback mechanisms.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If amplify-and-forward repeaters are deployed to extend wireless coverage, then coverage area is improved, but signal distortion and interference increase
Solution Approach 1:
The base station performs preliminary digital pre-distortion and pre-equalization of signals before transmission to the repeater. The repeater performs preliminary impairments correction based on pre-computed correction parameters. These preliminary actions compensate for anticipated distortion and interference before they occur, allowing the repeater to extend coverage while maintaining signal quality.
Solution Approach 2:
The system implements feedback mechanisms where the repeater measures its actual non-linear characteristics and droop, then reports these measurements to the base station. The base station uses this feedback to compute accurate correction parameters and adjust pre-distortion settings, enabling continuous optimization that maintains signal quality across extended coverage areas.
2Reliability
If digital pre-distortion and pre-equalization capabilities are added to repeaters, then signal quality is improved, but device complexity increases
Solution Approach 1:
The base station acts as an intermediary that performs the complex digital pre-distortion and pre-equalization computations remotely. The repeater only needs to implement simpler impairments correction functions using pre-computed parameters received from the base station, thereby improving signal quality while avoiding the complexity of full DPD/PEQ implementation at the repeater.
Solution Approach 2:
The patent replaces the need for complex hardware-based DPD/PEQ circuits at the repeater with a software-based solution where correction parameters are computed at the base station and applied at the repeater. This substitution of mechanical/electrical complexity with computational simplicity achieves signal quality improvement without increasing repeater hardware complexity.
3Measurement precision
If training sessions are conducted to measure non-linear characteristics and droop, then measurement precision is improved, but loss of time increases
Solution Approach 1:
The system performs partial training by measuring only the critical non-linear characteristics and droop parameters that have the greatest impact on signal quality. Rather than conducting exhaustive measurements of all possible impairments, the focused partial measurement approach achieves sufficient precision for effective correction while minimizing the time required for training sessions.
4Reliability
If base station performs pre-processing to compensate for repeater impairments, then signal quality is improved, but use of energy at base station increases
Solution Approach 1:
The base station dynamically adjusts the level of pre-processing applied based on measured impairment parameters. By changing processing parameters adaptively rather than applying fixed maximum processing, the system maintains signal quality while optimizing energy consumption. The pre-processing intensity is matched to the actual impairment severity, avoiding unnecessary energy expenditure.
Data Source
AI summary
Apparatuses and methods for base station assistance for impairments correction and handling for AF repeaters are described. An apparatus is configured to obtain a first indication of one or more conditions associated with a set of NL characteristics and a set of droop characteristics. The apparatus is also configured to measure the set of NL characteristics and the set of droop characteristics, where the set of NL characteristics and the set of droop characteristics are associated with a DPD training session. The apparatus is also configured to transmit, for a network node, one or more of: (1) a second indication of the measured set of NL characteristics and the measured set of droop characteristics, or (2) at least one of a list of excluded resources or a set of indexes for the list of excluded resources that are associated with interference at the wireless device.