MIMO Detector Using Multiple QR Decompositions for Low Complexity
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Solution Overview
Problem
MIMO communication receivers face high computation complexity, particularly in MIMO detection, which hinders performance and increases costs, especially in packet-based OFDM transmissions where processing for each OFDM symbol is repetitive and resource-intensive.
Innovation Solution
A hardware architecture design for MIMO detectors that optimizes channel processing and soft-output generation by using multiple QR Decompositions (MQRDs) and a reduced candidate search list based on channel fading conditions, distinguishing between sub-carriers for full or reduced search to balance memory usage and complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If MIMO detection is performed using traditional methods, then detection accuracy is improved, but computation complexity increases significantly
Solution Approach 1:
The patent segments the MIMO detection process into distinct functional units: channel processing unit, detection unit, and soft-output generation unit. Each unit handles specific tasks independently, allowing parallel processing and reducing overall computational complexity while maintaining detection accuracy through coordinated operation of these segmented components.
Solution Approach 2:
The patent performs preliminary channel processing and QR decomposition before the actual detection operation. By pre-computing channel matrices and preparing detection parameters in advance, the system reduces the computational burden during time-critical detection phases, thereby lowering real-time computation complexity without sacrificing accuracy.
2Measurement precision
If full search is performed for all sub-carriers, then detection performance is improved, but processing time and complexity increase
Solution Approach 1:
The patent applies different processing strategies to different sub-carriers based on local channel conditions. Sub-carriers experiencing fading are identified and handled with reduced search methods, while only critical sub-carriers undergo full search. This localized quality adjustment optimizes the balance between detection performance and processing time by avoiding unnecessary full searches on all sub-carriers.
Solution Approach 2:
The patent implements partial search strategies where a reduced candidate list is used for sub-carriers not experiencing severe fading. Instead of performing exhaustive full searches on all sub-carriers, the system applies partial search to sufficient subsets of sub-carriers, achieving acceptable detection performance with significantly reduced processing time.
3Measurement precision
If memory usage is increased to store more channel data, then processing accuracy is improved, but hardware costs and complexity increase
Solution Approach 1:
The patent extracts and processes only the essential channel information required for accurate detection, rather than storing and processing all available channel data. By identifying and extracting the critical components of channel state information, the system achieves high processing accuracy with reduced memory requirements and lower hardware complexity.
Solution Approach 2:
The system performs preliminary channel processing to pre-compute and store only the essential parameters needed for detection, such as pre-processed channel matrices and key statistical properties. This preliminary action reduces the volume of data that needs to be stored in memory during operation, thereby lowering hardware complexity while maintaining processing accuracy.
4Productivity
If high data rate is achieved through MIMO, then communication capacity is improved, but system complexity and cost increase
Solution Approach 1:
The patent segments the MIMO system into specialized functional units that handle different aspects of high-rate communication independently. This segmentation allows the system to achieve high data rates through parallel processing in these units while managing overall system complexity by distributing computational tasks across modular components rather than requiring a monolithic complex system.
Data Source
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AI summary
An embodiment of a method and device for detecting a signal and generating bit soft-output of a multiple-input multiple-output system is provided. The device includes at least one channel estimates pre-processing unit, one received vector processing and one detection and soft-output generation unit. The pre-processing unit calculates multiple QR Decompositions of the input channel estimation matrix. The detection and soft-output generation unit computes near optimal bit soft output information with a deterministic complexity and latency. It may implement a reduced complexity search method. Globally, embodiments of the invention may allow achieving low complexity, high data rate, scalability in terms of the dimension of the MIMO system and flexibility versus the supported modulation order, all potentially key factors for most MIMO wireless transmission applications.