MIMO Sphere Decoder Linear Startup Complexity Reduction
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Solution Overview
Problem
Current wireless local area network (WLAN) transceivers face challenges in improving Multiple-Input Multiple-Output (MIMO) reception capabilities, particularly in environments with obstacles, where collision detection is difficult and existing MIMO decoding methods are either complex or sub-optimal.
Innovation Solution
A wireless device equipped with multiple antennas, utilizing a MIMO demapper that performs both linear and non-linear decoding processes, with an initial linear decoding phase followed by non-linear sphere decoding, reducing complexity by extending the time interval for channel estimate decomposition and improving decoding efficiency.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If non-linear sphere decoding is used for MIMO reception, then decoding performance is improved, but computational complexity increases
Solution Approach 1:
The decoding process is segmented into two distinct phases: an initial linear decoding phase that processes the first received symbol, and a subsequent non-linear sphere decoding phase that processes remaining symbols. This segmentation allows the system to use simpler linear decoding for initial processing and reserve complex non-linear decoding for when it is most needed, thereby reducing overall computational complexity while maintaining decoding performance.
Solution Approach 2:
The system performs preliminary linear decoding of the first received symbol before initiating non-linear sphere decoding. This preliminary action extends the time interval available for channel estimate decomposition and reduces the complexity burden on the non-linear decoding phase, as some decoding work has already been completed using less computationally intensive linear methods.
2Device complexity
If linear decoding is used for MIMO reception, then computational complexity is reduced, but decoding performance becomes sub-optimal
Solution Approach 1:
The decoding system dynamically switches between linear and non-linear decoding methods based on the processing stage. Initially, linear decoding is used for the first received symbol to reduce complexity, then the system transitions to non-linear sphere decoding for remaining symbols to improve performance. This dynamic adaptation allows the system to optimize between complexity and performance at different stages of the decoding process.
3Productivity
If MIMO decoding is performed in real-time, then communication efficiency is improved, but processing time requirements increase
Solution Approach 1:
The decoding process is divided into temporal segments where linear decoding handles the initial symbol processing and non-linear sphere decoding handles subsequent symbols. This segmentation allows the system to perform decoding operations in a structured time sequence, improving real-time processing efficiency by avoiding the need to perform all complex non-linear decoding operations immediately for every symbol.
Data Source
AI summary
A wireless device with multiple antennae and configured to support orthogonal frequency-division multiplexed (OFDM), multiple-input multiple-output (MIMO) communications of a wireless local area network (LAN) over a wireless communication medium on a communication channel. The wireless device comprises: a MIMO demapper configured to receive a packet on the communication channel and to perform both linear together with non-linear decoding processes based on an initial communication channel estimate ‘H’, and with initial linear decoding of at least a first received symbol in a payload portion of the received packet followed by decoding of remaining symbols in the packet using non-linear sphere decoding, thereby reducing a level of complexity associated with non-linear decoding by extending a time interval available for an initial channel estimate decomposition portion of non-linear sphere decoding to span at least a portion of a n interval associated with linear decoding of at least the first received payload symbol.