Reception Quality Measuring Apparatus Lattice Distance Estimation
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Solution Overview
Problem
Conventional reception quality measuring apparatuses face high calculation burdens and circuit complexity in estimating interference signal strength indicator (ISSI) and noise levels, particularly due to the need for weighting past and current estimates and error correction in mobile communication systems.
Innovation Solution
A reception quality measuring apparatus and method that performs equalizing processing on a reception signal to derive an equalized signal, calculates a lattice distance estimation, and uses this to estimate RSSI and ISSI, with ISSI derived by subtracting RSSI from the lattice distance, thereby reducing calculation complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the ISSI is estimated by weighting and adding past-estimated ISSI and currently estimated ISSI, then the estimation accuracy is improved, but the calculation amount becomes great
Solution Approach 1:
The patent performs preliminary action by estimating the total reception power using the lattice distance estimation value before deriving ISSI. This allows ISSI to be obtained through a simple subtraction operation (total reception power - RSSI) rather than requiring complex weighted averaging of multiple ISSI estimates, thereby reducing calculation complexity while maintaining estimation accuracy
Solution Approach 2:
The patent inverts the conventional approach by not directly estimating ISSI through complex algorithms. Instead, it estimates the total reception power first using lattice distance estimation, then derives ISSI as the difference between total reception power and RSSI. This inverse approach simplifies the calculation while achieving accurate ISSI estimation
2Measurement precision
If the noise level is estimated by performing error correction to an estimation value obtained by approximately estimating the grid point interval, then the noise level estimation is achieved, but the error becomes great and the calculation amount or circuit scale increases
Solution Approach 1:
The patent extracts only the necessary component for noise level estimation by using the imaginary part of the lattice distance estimation value directly, without performing complex error correction procedures. This extraction approach obtains accurate noise level estimation while avoiding the computational complexity and large circuit scale associated with traditional error correction methods
Solution Approach 2:
The patent uses the lattice distance estimation value (which can be computed efficiently) as a proxy or copy for the noise level estimation, avoiding the need to perform complex error correction on grid point interval estimates. This copying approach maintains estimation accuracy while significantly reducing computational requirements
3Measurement precision
If the total reception power estimation value is derived by performing addition averaging process on the electric power of equalized reception signal using the number of subcarriers, then the estimation is achieved, but the calculation amount becomes great
Solution Approach 1:
The patent extracts the total reception power estimation value directly from the lattice distance estimation value without performing addition averaging operations over multiple subcarriers. This extraction method obtains accurate total reception power estimation while avoiding the computationally intensive averaging process that would require processing each subcarrier individually
Solution Approach 2:
The patent performs preliminary action by obtaining the lattice distance estimation value, which inherently contains the total reception power information. This preliminary estimation eliminates the need for subsequent addition averaging operations, thereby reducing calculation amount while maintaining estimation accuracy
Data Source
AI summary
A reception quality measuring apparatus (100) including: an equalizing processing unit (1) for performing an equalizing process on a reception signal to derive an equalized reception signal; lattice distance estimating element (2) for deriving a lattice distance estimation value using the equalized reception signal; an RSSI estimating unit (3) for deriving an RSSI estimation value using the lattice distance estimation value; an ISSI estimating unit (4) for deriving an ISSI estimation value by subtracting the RSSI estimation value from the lattice distance estimation value; and a dividing unit (5) for deriving an SIR representing reception quality by dividing the RSSI estimation value by the ISSI estimation value.