Diversity Reception Device Correlation Weighting
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Solution Overview
Problem
Existing diversity reception systems with multiple branches face challenges in achieving optimal weighting for demodulated signals, particularly when dealing with weak wanted waves and strong unwanted waves, due to errors in gain control and reliance on pilot signals for reliability calculations.
Innovation Solution
A diversity reception device and method that utilize correlation signals to determine weighting factors independently of received signal levels, using time position detectors, autocorrelation, and integral calculations to control gain settings across branches, ensuring robust detection of weak signals and minimizing the impact of unwanted waves.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If weighting is performed based on reception levels (RSSI values, gain control values), then combining efficiency is improved, but measurement precision deteriorates due to gain control errors and unwanted waves
Solution Approach 1:
The patent introduces correlation signals as an intermediary measurement mechanism. Instead of directly measuring reception levels using RSSI or gain control values (which are affected by errors and unwanted waves), the system uses correlation between the received signal and delayed/reference signals to generate correlation signals. The levels of these correlation signals serve as a more accurate proxy for determining weighting factors, thereby resolving the contradiction between combining efficiency and measurement precision.
2Ease of operation
If pilot signals are used for reliability calculation, then carrier selection and combining is simplified, but reliability calculation accuracy deteriorates in branches with weak wanted waves and strong unwanted waves
Solution Approach 1:
The patent changes the parameter used for reliability assessment from pilot signal levels to correlation signal levels. By calculating correlation between received signals and delayed/reference signals, and using the levels of these correlation signals (rather than pilot signal levels) to determine weighting factors, the system maintains operational simplicity while significantly improving accuracy in difficult reception conditions where wanted waves are weak and unwanted waves are strong.
3Reliability
If gain control is applied to amplify weak signals, then signal detection capability is improved, but unwanted waves are also amplified causing measurement errors
Solution Approach 1:
The patent extracts the useful signal characteristic through correlation processing. By computing the correlation between the received signal and delayed/reference signals, the system separates the wanted signal components from unwanted waves and noise. The correlation signals contain only the relevant signal information needed for weighting determination, effectively filtering out the harmful amplified unwanted waves while preserving detection capability for weak wanted signals.
Data Source
AI summary
A diversity reception device includes branches, a controller and a combining section. Each branch includes a correlation section that generates a correlation signal that represents a correlation between a received signal and a delayed signal or between the received signal and a reference signal, where the correlation signal level disregarding the received signal level, a time position detector that detects time positions at which the level of the correlation signal is at a peak, a demodulation section that demodulates the received signal, and a multiplication section that multiplies the demodulated signal with a weighting factor. The controller controls the weighting factor on the basis of the respective levels of the correlation signals at the detected time positions. The combining section combines, by adding, the respective demodulated signals of the branches subsequent to the demodulated signal of each branch being multiplied with the weighting factor.