MIMO-OFDM Successive Interference Cancellation Decoder
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Solution Overview
Problem
Existing MIMO-OFDM systems face inefficiencies in decoding horizontally encoded transmissions, particularly in requiring buffering for parallel decoders and increased hardware requirements, which affects throughput and memory usage.
Innovation Solution
Implementing a single decoder that demodulates only one layer of the received tones at a time, using MIMO-1 mode for equalization, and applying successive interference cancellation (SIC) to selectively decode layers, thereby eliminating the need for pre-decoder buffering while maintaining throughput.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If parallel decoders are used for MIMO horizontal encoding and decoding, then decoding capability is improved, but hardware requirements and memory usage increase
Solution Approach 1:
The patent segments the decoding process into sequential stages: first decoding one codeblock, then using its result to aid decoding of the second codeblock. This temporal segmentation replaces spatial parallelism, allowing a single decoder to achieve the same functionality as multiple parallel decoders would provide, thus reducing hardware requirements while maintaining decoding capability.
Solution Approach 2:
The patent applies preliminary action by fully decoding the first codeblock before attempting to decode the second codeblock. The successfully decoded first codeblock is stored and used as a known quantity to simplify the decoding of the second codeblock. This preliminary decoding action reduces the computational complexity and hardware requirements for the overall MIMO decoding process.
2Productivity
If buffering is implemented for parallel decoders, then decoding efficiency is improved, but memory usage increases
Solution Approach 1:
The patent extracts and utilizes the decoded content of the first codeblock as a known quantity for decoding the second codeblock. Instead of buffering both codeblocks simultaneously for parallel processing, the system extracts the essential information from the first codeblock and uses it to reduce the buffering requirements for the second codeblock, thereby improving decoding efficiency while reducing memory usage.
Solution Approach 2:
The patent discards the need to buffer both codeblocks simultaneously by processing them sequentially. The first codeblock is decoded, its results are temporarily held and used for second codeblock decoding, then the buffering requirements are reduced. This approach recovers the functionality of parallel processing with reduced memory requirements through sequential processing with selective buffering.
3Device complexity
If a single decoder is used with successive interference cancellation, then hardware requirements are reduced, but computational load increases
Solution Approach 1:
The patent ensures continuity of useful action by maintaining the decoded first codeblock in memory and continuously utilizing it during the decoding of the second codeblock. This continuous utilization of the first codeblock's decoded information allows the single decoder to efficiently process the second codeblock without requiring additional hardware, thereby reducing hardware requirements while managing computational load through intelligent reuse of decoded information.
Data Source
AI summary
A method and system for receiving and decoding horizontally encoded MIMO-OFDM transmissions with improved efficiency. In one embodiment, MIMO decoding is performed on each of the extracted separate tones of a MIMO-OFDM signal to extract and demodulate frequency domain symbols of the first layer corresponding to one or more code blocks. For each code block of the first layer that passes an error check, corresponding portions of the second layer are decoded using SIMO decoding.