Adaptive MIMO Detection Switching Between K-best and SIC Modes

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Solution Overview

Problem

Existing MIMO detection methods face challenges in adaptively optimizing channel matrix preprocessing and decision thresholds, leading to increased system complexity and power consumption, and limited flexibility in accommodating varying channel conditions and M-QAM constellation sizes.

Innovation Solution

An adaptive MIMO detection method and system that dynamically switches between detection modes, performs sorted QR decomposition, and adjusts decision thresholds based on Signal to Noise Ratio, condition number, and interference term estimates to optimize channel preprocessing and detection strategies.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If optimal detection methods such as Maximum Likelihood (ML) detection are used, then bit error detection performance is improved, but detection complexity increases exponentially with the size of the QAM constellation and the number of spatial multiplexing data streams

Engineering Contradiction:
Improvebit error detection performanceVSAvoiddetection complexity
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent implements dynamic detection mode switching between K-best and SIC methods based on real-time channel condition assessment. The system transitions from static detection method selection to dynamic adaptation, where the detection algorithm is selected and adjusted according to varying channel conditions, thereby maintaining optimal performance while controlling complexity.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The patent changes the detection parameter (method selection) based on channel conditions. By monitoring channel characteristics and adjusting the detection method accordingly (switching between K-best and SIC), the system achieves near-optimal performance with reduced complexity compared to always using ML detection.

Inventive Principle:
Principle #35Parameter changes

2Device complexity

If linear sub-optimal detection methods such as Zero Forcing (ZF) and Minimum Mean Square Error (MMSE) are used, then detection complexity is reduced to the lowest level, but Receiver Diversity Gain is close to the single antenna system resulting in worst bit error performance

Engineering Contradiction:
Improvedetection complexityVSAvoidbit error performance
Core Design Contradiction:
Device complexityVSReliability

Solution Approach 1:

The system dynamically selects between linear (ZF/MMSE) and nonlinear (SIC/K-best) detection methods based on channel conditions. When channel conditions are poor, the system uses simple linear methods to minimize complexity. When channel conditions improve, it transitions to nonlinear methods to capture diversity gain, thus adapting the complexity-reliability tradeoff to actual system needs.

Inventive Principle:
Principle #15Dynamics

3Reliability

If nonlinear sub-optimal detection methods such as Successive Interference Cancellation (SIC) are used, then Receiver Diversity Gain is slightly increased, but the system becomes susceptible to error propagation

Engineering Contradiction:
ImproveReceiver Diversity GainVSAvoiderror propagation susceptibility
Core Design Contradiction:
ReliabilityVSDevice complexity

Solution Approach 1:

The patent incorporates feedback mechanisms where the system monitors detection performance and channel conditions. When error propagation is detected or channel conditions indicate high susceptibility to errors, the system switches back to more robust linear detection methods or adjusts the SIC threshold, thereby using feedback to control the error propagation issue.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts the detection method based on real-time channel assessment. By switching between SIC and other methods depending on channel conditions, the system maintains diversity gain benefits while minimizing error propagation susceptibility through adaptive method selection.

Inventive Principle:
Principle #15Dynamics

4Productivity

If K-best detector is used, then throughput rate independence from Signal to Noise Ratio (SNR) is ensured and performance is close to ML detection, but detection complexity is much lower than ML

Engineering Contradiction:
Improvethroughput rate independence from SNRVSAvoiddetection complexity
Core Design Contradiction:
ProductivityVSDevice complexity

Solution Approach 1:

The system dynamically switches between K-best and SIC methods based on channel conditions. While K-best provides SNR-independent throughput, the system can adapt to use simpler methods when channel conditions permit, thereby optimizing the balance between productivity and complexity based on actual operating conditions.

Inventive Principle:
Principle #15Dynamics

5Reliability

If existing MIMO detection methods are used, then detection performance is achieved, but adaptability to varying channel conditions and M-QAM constellation sizes is limited

Engineering Contradiction:
Improvedetection performanceVSAvoidadaptability to channel conditions
Core Design Contradiction:
ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent implements dynamic adaptation to varying channel conditions and M-QAM constellation sizes through real-time channel assessment and method switching. The system adjusts its detection strategy based on actual channel characteristics, providing versatility across different operating conditions while maintaining detection performance.

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The system changes detection parameters and methods based on channel conditions and constellation size. By adapting the detection method to match current system configuration and channel state, the system achieves both performance and adaptability, resolving the contradiction between fixed performance and flexible adaptation.

Inventive Principle:
Principle #35Parameter changes

Data Source

PatentUS11711155B2Self-adaptive MIMO detection method and system
Publication Date: 2023.07.25 ESPRESSIF SYST SHANGHAI
  • US11711155B2 patent drawing
  • US11711155B2 patent drawing
  • US11711155B2 patent drawing

AI summary

The present disclosure discloses an adaptive MIMO detection method and system. The method includes the following steps: a) determining whether a Signal to Noise Ratio of a data packet is greater than a set threshold for Signal to Noise Ratio, and if yes, performing ZF preprocessing on the channel matrix, and if not, performing MMSE preprocessing on the channel matrix; b) performing sorted QR decomposition on the channel matrix processed in step a) to obtain a plurality of decomposition matrices; c) determining whether a condition number of the channel matrix of the data packet is greater than a set threshold for condition number of the channel, and if yes, Lattice Reduction is performed on the decomposition matrices obtained in step b); d) determining whether an estimated value of an interference term of the channel matrix is greater than a threshold for the estimated value of the interference term of the channel matrix, and if yes, SIC detection mode is selected for MIMO detection on the data packets, and if not, K-best detection mode is selected for MIMO detection on the data packets; and e) according to processing results from steps a) to d), performing MIMO detection on the data packet.