LTE Uplink Signal Detection via Interference Whitening
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Solution Overview
Problem
The conventional Minimum Mean Square Error (MMSE) based detection method in LTE uplink systems fails in heterogeneous interference conditions due to uneven power spectrums and complex interference analysis from multiple sources like cordless phones, Bluetooth devices, and microwave ovens, which affects system performance and throughput.
Innovation Solution
A signal detection method and device that performs Fast Fourier Transform, extracts LTE uplink DMRS, calculates channel gains, combines signals, and applies interference pre-processing to transform non-white noise into white noise using eigenvalue decomposition and whitening operations, enabling effective frequency-domain equalization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional MMSE based detection method is used in LTE uplink, then inter-symbol interference caused by frequency-selective fading can be suppressed, but the detection algorithm completely fails in the presence of heterogeneous system interferences
Solution Approach 1:
The patent applies interference pre-processing before the main detection algorithm. Specifically, it performs eigenvalue decomposition on the interference covariance matrix and transforms the received signal through a pre-processor that whiten the interference. This preliminary action removes the harmful heterogeneous interference components before the signal enters the MMSE detector, enabling the system to handle both frequency-selective fading and heterogeneous interferences effectively
Solution Approach 2:
The patent introduces an interference pre-processor as an intermediary component between the received signal and the MMSE detector. This pre-processor uses eigenvalue decomposition to identify and separate interference components from desired signals, then transforms the signal to remove interference while preserving useful information. This intermediary structure enables the system to adapt to heterogeneous interference conditions without compromising the existing MMSE detection capability
2Measurement precision
If interference pre-processing is added to handle heterogeneous interferences, then detection precision in interference conditions is improved, but system complexity increases due to eigenvalue decomposition and additional processing steps
Solution Approach 1:
The patent segments the detection process into distinct functional modules: interference covariance matrix estimation, eigenvalue decomposition, pre-processing transformation, and MMSE detection. Each module performs a specific function, making the complex overall process more manageable and implementable. The segmentation allows for optimized implementation of each stage while maintaining overall detection precision
Solution Approach 2:
The patent uses eigenvalue decomposition to create a transformed version of the received signal that copies the essential information while removing interference. The pre-processor generates a cleaned signal copy that preserves the useful signal components while eliminating heterogeneous interference, enabling accurate detection without requiring complete redesign of the detection architecture
Data Source
AI summary
A method and device for detecting a signal of an LTE uplink system in an interference condition. The method comprises: receiving baseband signals of M receiving antennas, and after fast Fourier transform, conducting demapping to obtain frequency-domain baseband signals; extracting a DMRS inserted in a received signal of each antenna, and then, calculating a channel gain hl,k of each receiving antenna; combining the baseband signals and the channel gains of the M receiving antennas to obtain a signal matrix Yk and a gain matrix Hk; calculating an interference noise covariance matrix Rk on each subcarrier; conducting interference pre-processing on a received signal on each combined subcarrier to obtain the received signal (1) and the channel gain (2) after the interference pre-processing, where D=Rk−1/2; and according to (3), conducting frequency-domain balancing on the received signal after the interference pre-processing.