JT-MU-MIMO Transmission Weight Interpolation with Timing Correction
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Solution Overview
Problem
Existing JT-MU-MIMO systems face challenges in computing optimal frequency-dependent transmission weights due to varying propagation delays between transmission points and user equipment, leading to increased processing load and difficulty in interpolating accurate weights, especially with large delay differences.
Innovation Solution
A communication device computes reflected transmission weights based on timing correction coefficients and channel estimation values, interpolating them at narrower frequency intervals, and corrects these weights to account for timing differences, ensuring accurate phase rotation suppression and optimal weight application.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the frequency band is divided into predetermined band segments to acquire optimal frequency-dependent transmission weights, then the transmission weight accuracy is improved, but the processing load increases
Solution Approach 1:
The frequency band is divided into multiple band segments, and transmission weights are computed for each segment separately. This segmentation allows the system to capture frequency-dependent characteristics of the channel while managing computational complexity through localized processing in each band segment.
Solution Approach 2:
The patent changes the frequency interval parameter by computing transmission weights at wider frequency intervals first, then interpolating to obtain weights at narrower frequency intervals. This parameter transformation reduces the direct computational burden while maintaining accuracy through mathematical interpolation techniques.
2Productivity
If transmission weights are computed without increasing the number of segments, then the processing load is reduced, but the interpolation accuracy deteriorates when there are large differences in propagation delays
Solution Approach 1:
The patent applies preliminary timing correction to the channel estimates before computing transmission weights. By pre-aligning the timing of uplink signals from different UEs, the system creates more favorable conditions for subsequent weight computation and interpolation, reducing the adverse effects of large propagation delay differences.
Solution Approach 2:
The patent introduces timing correction coefficients as an intermediary element that mediates between the raw channel estimates and the final transmission weights. These coefficients compensate for timing differences and enable more accurate interpolation by providing a corrected reference framework.
3Measurement precision
If transmission weights are interpolated at narrower frequency intervals, then the frequency resolution is improved, but the phase rotation fluctuations increase when there are large propagation delays
Solution Approach 1:
The patent performs preliminary timing correction on channel estimates before interpolation. This pre-processing step stabilizes the phase characteristics across frequency by aligning timing references, thereby enabling accurate interpolation at narrow frequency intervals without introducing excessive phase rotation fluctuations.
Data Source
AI summary
A communication device that is configured to: compute reflected transmission weights based on timing correction coefficients to be applied to each of a plurality of antennas according to reception timings of uplink signals from a plurality of wireless terminals that receive multiplexed downlink signals transmitted from the plurality of antennas, and on respective channel estimation values between the plurality of antennas and the plurality of wireless terminals, the computed reflected transmission weights reflecting the timing correction coefficients and being computed at first frequency intervals; compute interpolated transmission weights by interpolating between the computed reflected transmission weights at second frequency intervals that are narrower than the first frequency intervals; and compute transmission weights to be applied to downlink signals by, based on the timing correction coefficients, correcting the interpolated transmission weights that have been interpolated such that the timing correction coefficients are reflected a second time.