Parallel SIC Detection Reducing MIMO Memory Requirements
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Solution Overview
Problem
Conventional MIMO detectors in communication systems face inefficiencies due to large signal buffers required for channel decoding and interference cancellation, which are exacerbated by the need for successive interference cancellation and the uncertainty of whether interference cancellation will be successful during data stream decoding.
Innovation Solution
An improved SIC detector uses predetermined LMMSE filters for a second MIMO data stream, storing LMMSE filter outputs instead of original signal samples, and performing interference cancellation only after successful decoding of the first data stream, allowing for parallel detection and storage of results for successful and unsuccessful interference cancellation scenarios.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If successive interference cancellation is performed with channel decoding, then interference cancellation effectiveness is improved, but large signal buffers are required causing increased memory requirements
Solution Approach 1:
The patent performs preliminary detection of the second data stream in parallel with the detection of the first data stream, storing two possible detection results before channel decoding completes. This preliminary action eliminates the need to buffer entire signal samples for later interference cancellation, reducing memory requirements while maintaining cancellation effectiveness.
Solution Approach 2:
The patent segments the detection process by separating the detection of the first data stream from the detection of the second data stream. The second stream detection is performed in parallel and segmented into two possible outcomes (with or without interference cancellation), allowing selective processing based on first stream decoding success without requiring full signal buffering.
2Measurement precision
If interference cancellation is performed for all data streams, then detection accuracy is improved, but computational complexity increases
Solution Approach 1:
The patent applies partial interference cancellation by performing detection for the second data stream in parallel without always executing full interference cancellation. The cancellation is selectively applied only when the first data stream decoding succeeds, avoiding unnecessary computational complexity while maintaining detection accuracy when needed.
Solution Approach 2:
The patent introduces dynamic decision-making where the interference cancellation operation is conditional based on the decoding outcome of the first data stream. The system adapts its processing path dynamically - either performing interference cancellation or using the parallel detection result directly - optimizing computational resources based on actual channel conditions.
3Reliability
If signal samples are buffered for channel decoding delay, then successful interference cancellation is enabled, but large memory resources are consumed
Solution Approach 1:
The patent performs preliminary parallel detection of the second data stream before channel decoding of the first stream completes. This preliminary action stores only detection results (not entire signal samples), enabling interference cancellation to proceed successfully when needed while consuming minimal memory resources.
Solution Approach 2:
The patent creates a copy of the detection result for the second data stream and stores it in advance. This copied result can be used directly for interference cancellation without needing to retain the original signal samples, significantly reducing the buffer size required while maintaining cancellation effectiveness.
Data Source
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AI summary
An apparatus for determining a symbol estimate includes a detection unit, an information storage, a channel decoder, and an estimator. One or more detectors of the detection unit is configured to detect a first data stream and the one or more detectors or one or more other detectors are configured to detect a second data stream when interference cancellation is carried out and when interference cancellation is not carried out parallel to detection of a first data stream to obtain results of detection. The information storage is configured to store the results of the detection of the second data stream, and the channel decoder is configured to channel decode a detected first data stream. The estimator is configured to determine a symbol estimate by using the stored results of the detection of the second data stream and based on the success of the channel decoding of the first data stream.