LDPC Puncturing Scheme for Multi-Rate Signal Transmission
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Solution Overview
Problem
Current wireless communication systems face limitations in supporting various coding rates for high-speed, high-capacity data transmission/reception using Low Density Parity Check (LDPC) codes due to cyclic structure restrictions and complex hardware implementation, necessitating a scheme to transmit/receive signals at multiple coding rates without increasing the number of encoders and decoders.
Innovation Solution
The implementation of a puncturing scheme for LDPC codes, where only a part of the parity vector is transmitted, allowing for varying coding rates using a single encoder and decoder, with a proposed puncturing pattern to optimize performance, and a method to generate a parity check matrix that supports multiple coding rates by puncturing parity symbols according to a targeted rate.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If multiple encoders and decoders are used to support various coding rates, then coding rate adaptability is improved, but device complexity increases
Solution Approach 1:
The patent applies universality by designing a single encoder and decoder that can operate at multiple coding rates through a puncturing mechanism. The encoder generates codewords at a base coding rate, and the decoder is configured to handle both punctured and non-punctured codewords, allowing the same hardware to adapt to different coding rates (e.g., 1/3, 2/3, 3/4) without requiring separate encoders and decoders for each rate.
Solution Approach 2:
The patent changes the parameter of the decoding process by configuring the decoder with multiple possible configurations corresponding to different coding rates. The decoder can be switched between different decoding modes (e.g., decoding a codeword as if it were punctured versus non-punctured) depending on the actual coding rate used, allowing a single decoder to handle multiple coding rates through parameter adjustment rather than hardware multiplication.
2Adaptability or versatility
If puncturing is applied to achieve arbitrary rate, then coding rate flexibility is improved, but performance of punctured codes deteriorates
Solution Approach 1:
The patent applies preliminary action by pre-configuring the decoder with knowledge of possible puncturing patterns and their corresponding coding rates. The decoder is designed in advance to recognize and correctly decode codewords that have been punctured according to specific patterns, eliminating the need for complex rate-compatible punctured LDPC codes and ensuring optimal decoding performance across all supported coding rates.
Solution Approach 2:
The patent creates multiple virtual copies of the decoding process within a single decoder architecture, where each copy corresponds to a different coding rate configuration. This allows the decoder to simulate different decoding scenarios and select the appropriate one based on the actual transmitted codeword, maintaining high decoding performance without requiring physically separate decoders for each coding rate.
Data Source
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AI summary
In a communication system, a signal transmission apparatus includes an encoder for encoding an information vector into a low density parity check (LDPC) codeword with an LDPC coding scheme, and a puncturer for puncturing the LDPC codeword according to a coding rate using a puncturing scheme. A signal reception apparatus includes a '0' inserter for inserting '0' symbols in a received signal according to a coding rate used in a signal transmission apparatus, and a decoder for decoding the '0' symbol-inserted signal with a decoding scheme corresponding to a low density parity check (LDPC) coding scheme used in the signal transmission apparatus, thereby detecting an information vector.