Multi-User MIMO Reception Device Timing Offset Handling
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Solution Overview
Problem
In multi-user MIMO systems employing single-carrier or multicarrier transmissions, the challenge lies in separating signals from multiple transmitting stations when their arrival timings differ, leading to orthogonality destruction and performance deterioration if guard intervals are not adequately aligned.
Innovation Solution
A reception device with orthogonal conversion units, detection units, and rectangular filters to extract and align time series data, minimizing the impact of timing offsets while using multi-user detection weights and interference cancellation techniques to enhance signal separation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If guard intervals are inserted to maintain signal orthogonality in multi-user MIMO systems, then signal separation performance is improved, but system complexity and hardware requirements increase
Solution Approach 1:
The patent changes the parameter of guard interval length dynamically based on timing offset conditions. By adjusting the guard interval length to match the maximum timing offset between transmitting stations, the system maintains signal orthogonality without requiring excessive hardware complexity. This parameter optimization allows the receiver to handle timing misalignments effectively while keeping the system design practical.
2Reliability
If guard interval length is increased to accommodate timing offsets between transmitting stations, then signal orthogonality is maintained, but transmission efficiency decreases
Solution Approach 1:
The patent applies partial action by inserting guard intervals only where necessary - specifically, only at the boundaries between blocks from different transmitting stations that have timing offsets. Within each block, normal transmission continues without redundant guard intervals. This selective application maintains orthogonality where needed while preserving transmission efficiency in regions where timing alignment is not an issue.
3Reliability
If timing synchronization is strictly enforced between multiple transmitting stations, then signal orthogonality is maintained, but system adaptability and ease of operation deteriorate
Solution Approach 1:
The patent performs preliminary estimation of timing offsets between transmitting stations before signal processing. By calculating and compensating for these offsets in advance, the system can handle unsynchronized transmissions from multiple stations without losing orthogonality. This preliminary action enables the system to adapt to different timing conditions automatically, improving both robustness and ease of operation.
Data Source
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AI summary
Orthogonal converters perform orthogonal conversion on the N time-series data extracted from a received radio signal. Multi-user detectors extract transmitted signals from respective transmission devices, from the time-series data which has been subjected to the orthogonal conversion. Inverse orthogonal converters perform inverse orthogonal conversion on the extracted transmitted signal. Rectangular filter circuits remove Mh time-series data at the front end and Mt time-series data at the rear end, from the transmitted signal which has been subjected to the inverse orthogonal conversion, so as to extract Nw time-series data. Deinterleaver circuits deinterleave the aforementioned time-series data. Decoders decode the time-series data for output.