Adaptive MIMO Codebook Selection for High-Speed Terminals
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Solution Overview
Problem
Conventional 4×4 MIMO systems experience performance degradation at high mobile terminal speeds, and determining rank information and precoding indices is computationally complex, especially with large codebooks.
Innovation Solution
A mobile terminal uses a full-size or reduced-size precoder codebook based on its speed to determine the recommended transmission rank and precoder matrix, transmitting this information to the network to reduce computational complexity and improve performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a full-size codebook is used to determine rank information and precoding indices, then transmission performance is improved, but computational complexity at the mobile terminal increases significantly
Solution Approach 1:
The patent applies dynamics by making the codebook size adaptive based on mobile terminal speed. The system dynamically switches between full-size and reduced-size codebooks according to the measured speed threshold, allowing the computational resources to be adjusted according to actual channel conditions and mobility requirements.
Solution Approach 2:
The patent changes the parameter of codebook size based on mobile terminal speed. When speed exceeds a threshold, the system transitions from using a full-size codebook to a reduced-size codebook, thereby changing the computational complexity parameter while maintaining acceptable transmission performance for high-speed scenarios.
2Speed
If conventional MIMO systems operate at high mobile terminal speeds, then coverage is maintained, but performance degradation occurs due to outdated channel information
Solution Approach 1:
The system dynamically adapts the codebook selection based on mobile terminal speed measurements. When the terminal exceeds a speed threshold, the system switches to a reduced-size codebook that is more suitable for high-speed scenarios where channel information may be outdated, thereby maintaining transmission performance despite mobility-induced channel variations.
3Productivity
If the number of antennas is increased to improve system capacity, then spectral efficiency increases, but determining rank information and precoding indices becomes more computationally demanding
Solution Approach 1:
The patent makes the codebook size dynamic based on mobile terminal speed. For systems with multiple antennas (e.g., 4×4 MIMO or 8×8 MIMO), the system adapts between full-size and reduced-size codebooks, allowing the mobile terminal to handle larger antenna configurations without excessive computational burden, especially in high-speed scenarios where reduced codebooks are used.
Data Source
AI summary
A mobile terminal can receive N or less different data streams transmitted in parallel over N antennas. The number of different data streams actually transmitted in parallel to the mobile terminal corresponds to transmission rank. If the speed of the mobile terminal does not exceed a predetermined threshold, the mobile terminal utilizes a full-size codebook containing precoder elements for all N transmission ranks to determine a recommended transmission rank and precoder matrix for use in transmitting data to the mobile terminal. Otherwise, the mobile terminal utilizes a reduced-size codebook which excludes the precoder elements for at least transmission rank-N to determine the recommended transmission rank and precoder matrix where transmission rank-N corresponds to N different data streams being transmitted in parallel over the N antennas. The mobile terminal transmits an indication of the recommended transmission rank and precoder matrix to the network.