MIMO Precoding Bit Alignment for LDPC Codeword Mapping
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Implementing the MIMO scheme effectively when using LDPC coding, as existing methods face challenges in optimizing data processing and bit length adjustments for efficient transmission.
Innovation Solution
A data processing scheme that includes an encoding step for outputting an N-bit codeword, a mapping step for generating complex signals, and a bit length adjustment step to ensure the second bit sequence has a bit length that is a multiple of X+Y, facilitating the MIMO scheme's implementation with LDPC coding.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC coding is applied to MIMO transmission, then error correction capability is improved, but bit length alignment complexity increases
Solution Approach 1:
The patent applies preliminary action by performing bit length adjustment before the mapping step. The bit length adjustment unit pads the encoded bit sequence with zeros to ensure the length is a multiple of (X+Y), where X and Y are the bit lengths required for the first and second complex signals respectively. This preliminary alignment simplifies subsequent MIMO mapping operations and avoids complex real-time adjustments during transmission processing.
Solution Approach 2:
The patent introduces a bit length adjustment unit as an intermediary component between the LDPC encoder and the MIMO mapping unit. This intermediary performs the necessary bit sequence padding to align lengths, acting as a buffer that decouples the encoding process from the mapping process. This mediator simplifies the overall system architecture by handling the complexity of bit length alignment in a dedicated, manageable stage.
2Productivity
If bit length adjustment is performed to ensure multiple of X+Y, then MIMO mapping efficiency is improved, but processing time increases
Solution Approach 1:
The bit length adjustment is performed as a preliminary step before MIMO mapping, allowing the system to prepare optimized bit sequences in advance. By ensuring the bit length is a multiple of (X+Y) before mapping begins, the system enables more efficient parallel processing and resource utilization during the actual MIMO transmission, reducing overall processing time despite the initial adjustment overhead.
Data Source
AI summary
An encoder outputs a first bit sequence having N bits. A mapper generates a first complex signal s1 and a second complex signal s2 with use of bit sequence having X+Y bits included in an input second bit sequence, where X indicates the number of bits used to generate the first complex signal s1, and Y indicates the number of bits used to generate the second complex signal s2. A bit length adjuster is provided after the encoder, and performs bit length adjustment on the first bit sequence such that the second bit sequence has a bit length that is a multiple of X+Y, and outputs the first bit sequence after the bit length adjustment as the second bit sequence. As a result, a problem between a codeword length of a block code and the number of bits necessary to perform mapping by a set of modulation schemes is solved.