Interleaved Codeword Mapping for Fading and MIMO Transmission
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Solution Overview
Problem
Current communication systems using self-orthogonal codes and LDPC-CCs are inadequate for channels with correlation, such as fading channels and MIMO channels, particularly in mobile communication systems, as they fail to effectively correct errors due to burst errors and spatial correlation, and are limited to BPSK modulation, lacking consideration for higher-speed M-ary modulation.
Innovation Solution
A transmitting apparatus that employs error correction encoding using self-orthogonal codes or LDPC-CCs, along with an interleaver that rearranges codeword symbols to enhance correlation between channel characteristics, ensuring non-correlated symbols are not used in decoding, thereby improving error correction capability in fading and MIMO channels and supporting M-ary modulation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If self-orthogonal code or LDPC-CC is used for error correction encoding, then the encoder configuration becomes simple and decoding can be performed with majority logic decoding, but the error correction capability is inferior to maximum-likelihood decoding and convergence characteristic in iterative decoding is insufficient
Solution Approach 1:
The patent transforms the binary self-orthogonal code into a non-binary code operating over a larger finite field GF(q). This parameter change in the algebraic structure allows the code to achieve better error correction capability while maintaining the self-orthogonal property, enabling improved performance with iterative decoding without increasing encoder complexity
Solution Approach 2:
The patent employs iterative decoding where the decoding process is repeated multiple times with updated soft decision values. This dynamic approach allows the decoder to progressively improve error correction capability through repeated processing, transforming a static single-pass decoding into a dynamic iterative process that converges to better solutions
2Adaptability or versatility
If conventional error correction methods are used in fading channels or MIMO channels, then the system can operate in mobile communication environments, but burst errors and spatial correlation cause insufficient error correction performance
Solution Approach 1:
The patent extends the code from binary to non-binary over GF(q), adding an algebraic dimension to the code structure. This dimensional expansion provides additional degrees of freedom in the code design, enabling better handling of correlated errors in fading and MIMO channels while maintaining compatibility with the existing channel environments
3Reliability
If BPSK modulation is used, then the system achieves reliable transmission, but transmission speed is limited and M-ary modulation for higher speeds has not been sufficiently considered
Solution Approach 1:
The patent creates a universal error correction code over GF(q) that can support multiple modulation schemes. The non-binary code structure is adaptable to both BPSK and M-ary modulations, providing a single flexible solution that maintains reliability across different transmission speeds and modulation orders, enabling the system to achieve both reliability and higher speeds
Data Source
AI summary
Provided is a transmission device which improves the error rate characteristic upon decoding when performing error correction encoding by using a self-orthogonal code or an LDPC-CC in a communication system using a communication path having a fading fluctuation, multi-value modulation, or MIMO transmission. In the transmission device, the self-orthogonal encoding unit (110) encodes a self-orthogonal code having a constriction length K and an interleave unit (130) rearranges a code word sequence so that the same modulation symbol includes an information bit of a moment i and a non-correlated bit of the information bit of the moment i in a multi-value modulation unit (150).