Processor Unit for EVM Estimation via Signal Transformation
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Solution Overview
Problem
Existing digital communication systems face inefficiencies in estimating the Error Vector Magnitude (EVM) and Signal-to-Noise Ratio (SNR) due to the need for complex algorithms and overhead bandwidth usage, which complicates the determination of communication channel quality.
Innovation Solution
A processor unit with transformation logic circuitry that applies a sequence of transformations, including absolute value calculation and complex number operations, to move received complex values into a single target region, simplifying EVM estimation without requiring maximum likelihood algorithms or additional training sequences, thereby optimizing bandwidth usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If maximum likelihood detection algorithm is used to estimate EVM, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent segments the complex EVM estimation process into two parts: (1) a simplified initial estimation using basic signal processing, and (2) an optional refinement stage. This segmentation allows the system to achieve acceptable EVM measurement precision without always requiring the computationally intensive maximum likelihood algorithm, thus reducing device complexity while maintaining measurement accuracy when needed.
Solution Approach 2:
The patent employs simpler, computationally inexpensive estimation methods that can be quickly computed as a first approximation. These 'cheap' estimation techniques provide sufficient accuracy for many applications without requiring the expensive (computationally) maximum likelihood algorithm, effectively using disposable low-complexity solutions instead of always deploying high-complexity algorithms.
2Measurement precision
If training sequences are used for channel quality estimation, then measurement precision is improved, but loss of information increases
Solution Approach 1:
The patent enables the system to perform channel quality estimation using the actual data-bearing signal itself, without requiring separate training sequences. The estimation logic circuitry extracts channel quality information directly from the received signal's constellation points, allowing the signal to serve dual purposes: information transmission and channel quality measurement, thereby eliminating the need for dedicated training sequences and preventing bandwidth loss.
Solution Approach 2:
The patent makes the transmitted signal multi-functional by enabling it to simultaneously carry information and provide channel quality estimation data. The received signal is used both for data recovery and for calculating EVM and SNR metrics, eliminating the need for separate training sequences and maximizing bandwidth utilization for information transmission.
Data Source
AI summary
A processor unit used to determine a quality indicator, QI, of a communication channel. The processor unit receives received complex symbols at an input, executes a predetermined sequence of transformations on the received complex symbols and computes the error vector magnitude, EVM. The quality indicator, QI, of the communication channel is determined based on the determined error vector magnitude, EVM. Data representing the quality indicator, QI, is outputted at an output of the processor unit. The predetermined sequence of transformations transfers all the received complex symbols to a single predetermined region containing a single target location. The error vector magnitude, EVM, is then calculated as average distance of all the processed received complex symbols in the predetermined single region to the single target location.