Precoding Codebook Design for Uplink SU-MIMO
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Solution Overview
Problem
Current MIMO communication systems face limitations in uplink SU-MIMO transmissions, particularly in achieving high peak data rates and spectral efficiency due to constraints on precoding codebooks, which do not adequately address power amplifier imbalance and complexity in precoder selection.
Innovation Solution
The development of a precoding codebook for uplink SU-MIMO that employs a constant modulus, finite alphabet, and a low power rating, with a precoding matrix structure ensuring all elements have the same magnitude and only one non-zero element per row, to optimize transmission efficiency and reduce power amplifier backoff.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional precoding codebooks are used in uplink SU-MIMO transmissions, then the system can support multiple parallel data streams, but power amplifier imbalance and complexity in precoder selection limit the achievement of high peak data rates and spectral efficiency
Solution Approach 1:
The codebook is segmented into multiple subsets, each corresponding to a specific antenna port. This segmentation allows the UE to select precoders from a manageable subset rather than searching through the entire codebook, reducing selection complexity while maintaining high data rate capability through coordinated multi-antenna transmission
Solution Approach 2:
The patent changes the parameter structure of precoding matrices by enforcing constant modulus constraints and specific algebraic forms. This parameterization reduces the search space for precoder selection while ensuring compatibility with power amplifier characteristics, thereby reducing complexity without sacrificing productivity
2Productivity
If conventional precoding codebooks are used in uplink SU-MIMO transmissions, then the system can support multiple parallel data streams, but power amplifier imbalance and complexity in precoder selection limit the achievement of high peak data rates and spectral efficiency
Solution Approach 1:
The patent enforces constant modulus constraints on precoding matrix elements, which directly addresses power amplifier imbalance by ensuring uniform signal power across all antenna ports. This parameter constraint improves reliability of power amplification while maintaining spectral efficiency through optimized spatial multiplexing
Solution Approach 2:
The constant modulus constraint creates equipotential conditions across all transmit antennas by ensuring equal signal power levels. This eliminates power amplifier imbalance by making all amplifiers operate under identical power conditions, improving reliability without sacrificing spectral efficiency
3Adaptability or versatility
If precoding matrices with varying magnitudes are used, then flexibility in signal optimization is improved, but power amplifier imbalance increases and complexity rises
Solution Approach 1:
The patent changes the parameter space by restricting precoding elements to constant modulus values from a finite alphabet. This reduces the effective parameter space while maintaining adaptability through phase variations, thereby reducing complexity without sacrificing signal optimization flexibility
Solution Approach 2:
The patent applies different local qualities to different codebook subsets, where each subset is optimized for specific antenna configurations and channel conditions. This localized optimization maintains overall adaptability while reducing global complexity by allowing specialized handling of different scenarios
Data Source
AI summary
A transmitter is for use with multiple transmit antennas and includes a precoder unit configured to precode data for a transmission using a precoding matrix selected from a codebook, wherein the codebook corresponds to the following three transmission properties for an uplink transmission: 1) all precoding elements from the precoding matrix have a same magnitude, 2) each precoding element from the precoding matrix is taken from a set of finite values and 3) there is only one non-zero element in any row of the precoding matrix. The transmitter also includes a transmit unit configured to transmit the precoded data.