EVM Measurement Block for MIMO Signal Quality Assessment
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current communication systems face challenges in accurately measuring signal quality for production line testing and rate adaptation in multiple-rate systems, particularly in wireless MIMO systems, where received SNR or SINR is difficult to calculate due to interference and noise, leading to the need for a cost-effective and efficient method to assess channel conditions.
Innovation Solution
The integration of an EVM measurement block in receivers allows for the measurement of error vector magnitude (EVM) in both signal and data fields, enabling the determination of optimal spatial streams and modulation/coding schemes, and facilitating rate adaptation by using pre-calibrated Rx golden units for transmitter and receiver testing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If received SNR or SINR is used to measure signal quality, then measurement accuracy is improved, but device complexity and cost increase due to the difficulty of separating signal, interference and noise
Solution Approach 1:
The patent uses EVM measurement as a simpler, more cost-effective alternative to SNR/SINR measurement. EVM can be calculated using basic constellation point comparison without requiring complex signal separation techniques, making it suitable for production line testing and rate adaptation in cost-sensitive applications
Solution Approach 2:
The patent replaces the complex mechanical/signal processing system required for SNR/SINR measurement with a computational approach using EVM. The EVM calculation substitutes complex signal separation mechanics with straightforward distance measurement in the constellation diagram, achieving sufficient accuracy without the complexity of traditional methods
2Measurement precision
If expensive high-precision devices with pre-calibrated Rx units are used, then measurement precision is improved, but cost increases
Solution Approach 1:
The patent employs EVM measurement blocks that can be implemented in standard receivers without requiring expensive pre-calibrated equipment. The EVM calculation uses basic operations to determine distance from constellation points, eliminating the need for costly high-precision measurement devices while maintaining sufficient accuracy for production line testing
Solution Approach 2:
The patent creates a simplified measurement model using EVM that copies the essential information needed for quality assessment without requiring the full complexity of SNR/SINR measurement systems. This allows standard receivers to perform accurate measurements that previously required specialized expensive equipment
3Productivity
If multiple transmitters are tested simultaneously with a single vector signal analyzer, then productivity is improved, but measurement precision deteriorates due to signal interference
Solution Approach 1:
The patent segments the measurement process by having each transmitter include its own EVM measurement block. This allows simultaneous testing of multiple transmitters without interference, as each transmitter independently measures its own signal quality using its embedded EVM block rather than sharing a single external analyzer
Solution Approach 2:
The patent implements self-measurement capability where each transmitter measures its own signal quality using an embedded EVM measurement block. This eliminates the need for external measurement equipment and allows each device to independently assess its performance, enabling simultaneous testing without cross-interference
Data Source
AI summary
The present invention discloses an effective apparatus and method to measure the received signal quality for digital communication systems by measuring error vector measurement (EVM) with embedded EVM measurement block in receivers. The distinction of the present invention is that the EVMSIG and the EVMDATA are measured in the receiver for the SIGNAL fields and DATA fields, respectively. EVMSIG is a good indicator for one spatial stream and EVMDATA is a good indicator for current multiple streams. The receiver determines the optimum number of spatial data streams for feedback to the transmitter based on the combinations of EVMSIG and EVMDATA with or without other algorithms such as analysis on periodically requested sounding packet. The receiver also determines the optimum modulation and coding schemes for feedback based on the EVM measurements.