SC-FDMA Receiver MIMO Detection Complexity Reduction
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Solution Overview
Problem
The existing SC-FDMA systems face challenges in implementing Maximum-Likelihood (ML)-based MIMO receivers due to high computational complexity and exponential increase in candidate symbol vector size, making it difficult to perform ML-based MIMO detection in the frequency domain, and the performance of linear MIMO receivers is inferior.
Innovation Solution
A receiving apparatus and method that converts a multi-path channel into a single path channel in the frequency domain, using a constant channel matrix for channel equalization and ML-based MIMO detection in the time domain, reducing complexity and enabling efficient ML-based MIMO reception.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If ML-based MIMO detection is implemented in the frequency domain of SC-FDMA system, then detection accuracy is improved, but computational complexity increases exponentially
Solution Approach 1:
The patent inverts the conventional processing order by performing ML-based MIMO detection in the time domain instead of the frequency domain. The received frequency-domain signal undergoes IDFT to convert to time domain, then ML detection is performed, and finally FFT converts back to frequency domain for output. This inversion avoids the exponential complexity increase associated with frequency-domain ML detection while maintaining detection accuracy.
Solution Approach 2:
The patent changes the operational dimension from frequency domain to time domain for the ML detection process. By transforming the problem into the time domain using IDFT, the detection operates on a different dimensional representation of the signal, which fundamentally reduces the computational burden while preserving the essential detection functionality.
2Device complexity
If linear MIMO receiver is used in SC-FDMA system, then device complexity is reduced, but detection performance deteriorates
Solution Approach 1:
The patent changes the key parameter of detection domain from frequency domain to time domain. This parameter change enables the system to use ML-based detection (which provides superior performance to linear detection) while operating in the time domain where the computational complexity is manageable, thus achieving both good performance and acceptable complexity.
3Device complexity
If frequency domain channel equalization is performed in SC-FDMA system, then channel compensation is simplified, but multi-path effects cannot be fully eliminated
Solution Approach 1:
The patent inverts the conventional approach by performing channel equalization in the time domain rather than the frequency domain. The received signal is first converted to time domain via IDFT, then channel equalization is applied to remove multi-path effects more effectively, and finally the equalized signal is transformed back to frequency domain for subsequent processing. This inversion achieves better multi-path mitigation while maintaining computational efficiency.
Data Source
AI summary
A receiver and a receiving method for a Single Carrier Frequency Division Multiple Access (SC-FDMA) system are provided. The receiver includes a matrix selector for selecting a constant channel matrix according to a Multiple-Input Multiple-Output (MIMO) reception scheme, a channel equalizer for equalizing a multi-path channel to a specific path channel in a frequency domain by using the constant channel matrix, and a MIMO detector for detecting a Euclidean distance of transmittable symbols from a time-domain Transmit (Tx) signal by using the channel equalized in the frequency domain and then for selecting a symbol having a minimum distance.