LDPC Encoder Controller for Adaptive Modulation Coding
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Solution Overview
Problem
Next-generation communication systems, such as IEEE 802.16e and IEEE 802.11n, employ Adaptive Modulation and Coding (AMC) schemes but lack a concrete method to utilize channel codes like Low Density Parity Check (LDPC) codes, which are effective for high-speed data transmission and error correction.
Innovation Solution
An apparatus and method for determining and applying Modulation and Coding Schemes (MCS) levels or modulation schemes in communication systems, using LDPC codes for encoding and decoding signals, including a controller for selecting parity check matrices optimized for each MCS level or modulation scheme, and an encoder/decoder for generating and restoring information vectors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If AMC scheme is employed to increase data transmission amount, then productivity is improved, but reliability deteriorates due to lack of concrete channel code utilization method
Solution Approach 1:
The patent applies parameter changes by dynamically selecting different LDPC code rates (e.g., 1/2, 2/3, 3/4, 4/5) and modulation schemes (BPSK, QPSK, 16-QAM, 64-QAM) based on channel conditions. The controller adjusts these parameters to optimize both throughput and reliability, resolving the contradiction between increasing data transmission amount and maintaining transmission reliability.
2Productivity
If LDPC code is used for high-speed data transmission, then productivity is improved, but device complexity increases due to need for optimized parity check matrices for each MCS level
Solution Approach 1:
The patent applies preliminary action by pre-defining and storing multiple parity check matrices corresponding to different LDPC code rates (1/2, 2/3, 3/4, 4/5) and modulation schemes before transmission. The controller selects the appropriate pre-prepared matrix based on current channel conditions, avoiding real-time complex matrix generation and reducing encoding complexity while maintaining high-speed transmission capability.
3Reliability
If multiple parity check matrices are stored for different MCS levels, then reliability is improved, but memory requirements increase
Solution Approach 1:
The patent applies segmentation by dividing the LDPC code structure into multiple code rates (1/2, 2/3, 3/4, 4/5), each with its own optimized parity check matrix. This segmentation allows the system to store only the necessary matrices for specific MCS levels rather than all possible matrices, reducing memory requirements while maintaining reliable error correction for each segmentation category.
Data Source
AI summary
Disclosed is an apparatus and method for transmitting/receiving a signal in a communication system, in which an MCS level or a modulation scheme to be used to an information vector to be transmitted is determined when the information vector is generated, and a codeword vector is generated by encoding the information vector in an encoding scheme corresponding to the determined MCS level or modulation scheme. Thus, a signal can be transmitted in such a manner as to have optimal performance for each MCS level or modulation scheme.