Group-Wise STBICM MIMO Receiver Demapping
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Solution Overview
Problem
Existing MIMO receivers face high computational complexity in demapping processes, making them impractical for high spectral efficiency systems due to exponential complexity in processing multiple symbol streams, especially when the number of receive elements is less than the number of transmitted streams.
Innovation Solution
Implementing a demapper that operates on a group-wise basis, using single stream demappers and group stream demappers to reduce complexity by assigning streams into groups for independent demapping, with soft cancellation and spatial filtering to minimize interference, allowing for adjustable complexity based on receiver processing power.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If joint-stream demapping is used to process multiple symbol streams simultaneously, then decoding performance is improved, but computational complexity increases exponentially
Solution Approach 1:
The patent divides the set of Nt symbol streams into multiple groups, where each group contains a subset of streams. Instead of processing all streams simultaneously (joint-stream demapping), the system processes each group independently using group stream demappers. This segmentation reduces the computational complexity from exponential to manageable levels while maintaining decoding performance through iterative processing across multiple groups.
2Device complexity
If the number of receive elements is reduced to match the number of transmitted streams, then system complexity is reduced, but interference between streams increases
Solution Approach 1:
The patent implements an iterative detection process where soft information is exchanged between group stream demappers and a channel decoder across multiple iterations. In each iteration, the demappers use feedback information from previous iterations to refine their estimates, progressively reducing interference effects. This feedback mechanism allows the system to compensate for the reduced number of receive elements while maintaining acceptable performance.
3Device complexity
If group stream demapping is implemented with multiple groups, then computational complexity is reduced, but processing time increases due to iterative operations
Solution Approach 1:
The patent employs a dynamic iterative process where the number of iterations and the grouping configuration can be adjusted based on system conditions. The iterative detection allows the system to converge on optimal decisions progressively, balancing processing time and complexity. In practical implementations, the number of iterations is limited to achieve sufficient performance improvement within acceptable time constraints.
Data Source
AI summary
A STBICM MIMO receiver includes a plurality of demappers for demapping a plurality of complex symbols transmitted by a STBICM MIMO transmitter. Each demapper is configured to have one or more complex symbols associated therewith and is responsible for demapping its associated complex symbols.