Iterative Joint Parameter Estimation for LTE Advanced UL MIMO
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Solution Overview
Problem
Current measuring devices struggle to accurately determine parameters such as carrier frequency error, sample frequency error, phase noise, IQ offset, and channel estimation in LTE Advanced UL MIMO systems, where pilot symbols are transmitted simultaneously across all layers, making existing methods for SISO systems inapplicable.
Innovation Solution
A measuring device and method that iteratively estimate residual CFO, SFO, phase noise, IQ offset, and channel, using an iterative approach to handle the non-linear connection between channel and CFO, with digital processing means that adjust parameters based on pilot symbols and channel coefficients, allowing for accurate measurement even in the presence of simultaneous pilot signals.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If existing SISO estimation methods are used for LTE Advanced UL MIMO, then the measurement process is simple, but the measurement precision deteriorates because pilot symbols are transmitted simultaneously by all layers making existing approaches inapplicable
Solution Approach 1:
The patent segments the estimation process into multiple iterations, where each iteration estimates specific parameters (CFO, SFO, phase noise, IQ offset, channel) separately using updated values from previous iterations. This segmentation allows accurate estimation of all parameters despite the complex MIMO pilot structure, resolving the contradiction between operational simplicity and measurement precision.
Solution Approach 2:
The patent implements a dynamic iterative estimation process where parameter estimates are continuously refined across multiple iterations. The algorithm dynamically updates CFO, SFO, phase noise, IQ offset, and channel estimates using the most recent values, transforming a static single-step estimation into a dynamic multi-step process that achieves high precision for UL MIMO systems.
2Measurement precision
If joint minimization of frequency offset and channel is performed directly, then the estimation accuracy is improved, but the computational power required increases significantly because the non-linear problem cannot be solved directly
Solution Approach 1:
The patent segments the joint minimization problem into separate estimation steps for different parameters (CFO, SFO, phase noise, IQ offset, channel) that are performed iteratively. Each step focuses on estimating specific parameters using updated values from previous steps, avoiding the need for direct joint minimization of all parameters simultaneously. This segmentation maintains high estimation accuracy while significantly reducing computational complexity.
Solution Approach 2:
The patent performs partial minimization in each iteration by focusing on estimating specific parameters rather than performing complete joint minimization of all parameters in each step. The iterative process accumulates improvements across multiple partial minimization steps, achieving accurate joint estimation with lower computational power than direct complete minimization would require.
Data Source
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AI summary
A measuring device for determining at least a first parameter and a second parameter of a measuring signal, comprises receiving means for receiving the measuring signal and processing means (13). The measuring signal comprises a first signal and a second signal. The processing means (13) comprise parameter setting means (20, 30) for setting an initial value of the first parameter and iteration means (27, 37) for iteratively determining the parameters based upon the set initial value of the first parameter.