Gap-Aware Equalizer Coefficients for NR Base Station EVM Testing
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Solution Overview
Problem
Existing methods for calculating equalizer coefficients in new radio (NR) base station conformance testing fail to effectively address large gaps between allocated resource blocks (RBs) in the frequency domain, leading to inappropriate equalization and degraded error vector magnitude (EVM) values due to varying amplitude and phase characteristics across these gaps.
Innovation Solution
Adopting a modified moving average window size for DMRS subcarriers at the edges of RBs, combined with higher-order interpolation polynomials, to calculate equalizer coefficients for each RB, thereby addressing the gaps and improving EVM measurements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard moving average window size is used for equalizer coefficients across all resource blocks, then calculation simplicity is maintained, but measurement precision degrades due to inappropriate equalization at channel edges with large gaps between RBs
Solution Approach 1:
The patent applies different moving average window sizes to different resource blocks based on their location. Resource blocks at channel edges with large gaps use a first (smaller) window size, while resource blocks in the middle with smaller gaps use a second (larger) window size. This local differentiation ensures appropriate equalization for each RB's specific conditions, improving EVM measurement accuracy without uniformly increasing complexity across all RBs.
Solution Approach 2:
The patent segments the frequency domain into different regions based on gap sizes between resource blocks. By identifying and separating edge RBs with large gaps from middle RBs with smaller gaps, the system applies targeted equalization strategies to each segment. This segmentation allows the measurement system to handle different channel conditions appropriately, resolving the contradiction between precision and complexity.
2Measurement precision
If the moving average window size is reduced for edge resource blocks, then equalization accuracy at channel edges improves, but the amount of data used for averaging decreases
Solution Approach 1:
The patent dynamically changes the moving average window size parameter based on the specific conditions of each resource block. For edge RBs with large gaps, a smaller window size is selected to avoid including irrelevant subcarriers from distant RBs. For middle RBs with smaller gaps, a larger window size is used to充分利用 available subcarriers for better averaging. This parameter adaptation resolves the contradiction by optimizing the trade-off between accuracy and data quantity for each local condition.
Data Source
AI summary
According to a first embodiment, a method may include calculating at least one moving average window size in a frequency domain associated with a channel bandwidth and adjusting the at least one moving average window size in the frequency domain for at least one demodulation reference signal subcarrier in at least one resource block where at least one gap having a size of at least a predefined size is between the at least one resource block. The at least one resource block comprises a predetermined number of demodulation reference signal subcarriers.