Diversity Combining Using Residual Error Weights
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Solution Overview
Problem
Existing reception devices face performance degradation due to large channel estimation errors, especially when channel changes occur rapidly or when channel characteristics change within the interval occupied by the reference signal used for estimation, leading to inaccurate combining ratios in diversity techniques.
Innovation Solution
A reception device with multiple signal receiving units and signal processing units that transform received signals into frequency domain signals, calculate channel impulse responses, and compute residual error weights to adjust combining ratios dynamically, thereby mitigating the impact of channel estimation errors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If diversity combining is performed based on envelope ratios to maximize diversity gain, then the combining accuracy is improved when branches have identical C/Ns, but the error rate increases when branches have different C/Ns
Solution Approach 1:
The invention changes the parameter used for combining ratio calculation from envelope ratio to residual error weight. This parameter change allows the system to adapt to different C/N conditions, achieving both high diversity gain and accurate combining by using a parameter that reflects actual signal quality rather than just amplitude characteristics
Solution Approach 2:
The invention introduces feedback by calculating residual error weights based on the difference between received signals and equalized signals, then using these weights to adjust combining ratios. This closed-loop approach enables continuous optimization of combining accuracy while maintaining diversity gain, as the system continuously adapts to actual signal conditions
2Reliability
If channel estimation is performed using reference signals, then channel distortion can be compensated, but reception performance degrades when channel characteristics change within the reference signal interval
Solution Approach 1:
The invention performs preliminary channel estimation using reference signals to obtain initial channel characteristics, then uses this estimation to calculate residual error weights that guide subsequent diversity combining. This preliminary action enables the system to prepare compensation strategies in advance while accounting for potential channel variations during the reference signal interval
Solution Approach 2:
The invention introduces residual error weight as an intermediary parameter that bridges channel estimation results and diversity combining operations. This intermediary allows the system to translate channel estimation information into actionable combining ratios that account for estimation errors and rapid channel changes, improving overall reception performance
3Measurement precision
If the number of signal processing units is increased to handle rapid channel changes, then tracking accuracy is improved, but device complexity increases
Solution Approach 1:
The invention merges the functions of multiple signal processing units by performing diversity combining on frequency domain signals before inverse transformation. This consolidation maintains tracking accuracy for rapid channel changes while reducing device complexity, as the combining operation integrates information from multiple branches into a single processed signal stream
Solution Approach 2:
The invention transitions processing to the frequency domain, operating on frequency domain signals rather than time domain signals. This dimensional change enables more efficient handling of rapid channel variations through spectral analysis, achieving high tracking accuracy with reduced computational complexity compared to time domain processing of multiple branches
Data Source
AI summary
A reception device includes signal receiving units that generate received signals from signals obtained by receiving a transmitted signal at antennas, signal processing units that perform processes of generating received frequency domain signals by transforming the received signals to signals in the frequency domain, calculating channel impulse responses of the received signals, calculating estimated received signals from the channel impulse responses, and calculating residual error weights with values that decrease with increasing differences between the received signals and the estimated received signals, a combining ratio calculation unit that calculates combining ratios for the received frequency domain signals such that the ratios decrease as the residual error weights decrease, a diversity combining unit that combines the received frequency domain signals according to the combining ratios to generate a diversity combined signal, and an inverse Fourier transform unit that transforms the diversity combined signal to a time domain signal.