MIMO Precoding With Mixed Modulation for Spatial Diversity Gain
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Solution Overview
Problem
Current MIMO communication systems face challenges in efficiently transmitting and receiving data using multiple antennas, particularly in maintaining high data reception quality and spatial diversity gain with different modulation schemes and precoding matrices.
Innovation Solution
The proposed method involves performing error correction coding on information bit strings to generate code words, modulating bit strings using distinct modulation schemes for each antenna, and applying precoding matrices to ensure optimal spatial diversity gain and data reception quality by adjusting power and phase settings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If different modulation schemes are used for different antennas in MIMO communication, then adaptability to various channel conditions is improved, but maintaining high data reception quality and spatial diversity gain becomes difficult
Solution Approach 1:
The patent applies local quality by selecting different modulation schemes (QPSK, 16QAM, 64QAM) for different transmission streams based on their specific channel conditions. Each stream is independently modulated according to its own signal-to-interference ratio and channel characteristics, allowing optimal adaptation to local conditions while maintaining overall system reliability through independent stream processing and combining.
2Adaptability or versatility
If multiple transmission streams are processed independently, then adaptability to channel conditions is improved, but processing complexity increases
Solution Approach 1:
The patent segments the MIMO transmission into multiple independent processing streams, where each stream undergoes separate error correction coding, modulation, and precoding. This segmentation allows independent optimization of each stream according to its channel conditions while simplifying the overall processing architecture by avoiding complex joint processing of all streams simultaneously.
Solution Approach 2:
The patent implements dynamic selection of modulation schemes and precoding matrices for each transmission stream based on real-time channel conditions. The system dynamically adjusts the modulation order (QPSK, 16QAM, 64QAM) and precoding parameters for each stream independently, allowing adaptive optimization without requiring complex static processing structures.
3Adaptability or versatility
If code word length is not an integral multiple of (X+Y), then flexibility in coding is improved, but efficient modulation mapping becomes difficult
Solution Approach 1:
The patent segments the code word into two parts: a first bit string of length that is an integral multiple of (X+Y) and a second bit string containing the remaining bits. This segmentation allows the majority of the code word to be efficiently modulated using standard X-bit and Y-bit modulation schemes while accommodating any remainder bits through flexible handling methods such as adding dummy bits or adjusting the modulation order for the final symbols.
Solution Approach 2:
The patent changes the modulation parameters dynamically based on the code word length. When the code word length is not an integral multiple of (X+Y), the system adjusts the modulation scheme for the final symbols or adds dummy bits to achieve proper alignment. This parameter adjustment maintains coding flexibility while ensuring efficient modulation mapping for all code words regardless of their length.
Data Source
AI summary
In a transmission method according to one aspect of the present disclosure, a encoder performs error correction coding on an information bit string to generate a code word. A mapper modulates a first bit string in which the number of bits is the predetermined integral multiple of (X+Y) in the code word using a first scheme, the first scheme being a set of a modulation scheme in which an X-bit bit string is mapped to generate a first complex signal and a modulation scheme in which a Y-bit bit string is mapped to generate a second complex signal, and modulates a second bit string in which the first bit string is removed from the code word using a second scheme different from the first scheme.