LDPC Parity Distribution Across Antennas for Maximum Diversity
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Solution Overview
Problem
In multiple antenna communication systems, achieving maximum diversity and high data throughput is challenging due to signal distortion from noise, fading, and Inter-Symbol Interference (ISI), and existing channel coding techniques do not effectively manage the complexity of Low-Density Parity-Check (LDPC) codes for optimal diversity.
Innovation Solution
The method involves determining a parity-check matrix and generating a codeword using LDPC codes, with puncturing of the information word and division of parity into partial parities based on the number of transmit antennas, allowing for transmission and decoding that maximizes diversity across multiple antennas.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If LDPC codes are used for channel encoding in multiple antenna systems, then error correction capability and reliability are improved, but encoding and decoding complexity increases
Solution Approach 1:
The parity bits are divided into multiple groups corresponding to different transmit antennas. Each antenna transmits a specific group of parity bits, segmenting the overall encoding task and reducing the computational complexity at each receiver node while maintaining the full error correction capability of the LDPC code through collaborative decoding across all antennas.
Solution Approach 2:
The patent introduces a spatial dimension by distributing different parity bit groups across multiple transmit antennas. This transforms the single-dimension encoding problem into a multi-dimensional transmission scheme where the same LDPC code structure achieves complexity reduction through spatial parallelization without compromising reliability.
2Productivity
If puncturing is applied to reduce transmitted data, then data rate is improved, but signal quality and decoding reliability deteriorate
Solution Approach 1:
Different portions of the codeword (information bits vs. parity bits) are treated differently. The patent selectively transmits all information bits while only transmitting portions of the parity bits through puncturing. This local differentiation allows the system to prioritize transmission of critical information while using spatial diversity across multiple antennas to compensate for the punctured parity bits, maintaining signal quality while improving data rate.
3Reliability
If diversity is increased in space-time coding, then signal quality is improved, but system complexity and overhead increase
Solution Approach 1:
The patent merges channel encoding (LDPC) with space-time coding by integrating the parity bit distribution mechanism into the space-time transmission framework. Instead of treating encoding and spatial processing as separate stages, the system combines them by distributing encoded parity bits across antennas, achieving diversity gain while avoiding the complexity of separate space-time block coding schemes.
Data Source
AI summary
Methods and apparatuses are provided for achieving maximum diversity gain through channel coding based on a Low-Density Parity-Check (LDPC) code in a multiple antenna communication system. A method includes determining a parity-check matrix; generating a codeword using the parity-check matrix; puncturing a part of an information word; dividing a parity into a plurality of partial parities based on a number of transmit antennas; transmitting an unpunctured part of the information word and a partial parity over a first antenna; and transmitting at least one other partial parity over at least one other transmit antenna.