Baseband Signal Modulation for Beam Space MIMO RF Impairment Compensation
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Solution Overview
Problem
Beam space MIMO technology faces challenges in maintaining consistent phase and magnitude of emitted signals due to RF impairments, leading to difficulties in channel estimation and increased implementation complexity with multiple RF chains.
Innovation Solution
A baseband modulation apparatus that includes an antenna array, a baseband unit, a load calculator, a signal change controller, and a signal change unit to calculate and adjust the load value of parasitic antennas, ensuring phase and magnitude changes are consistent across baseband signals, thereby compensating for RF impairments and enabling normal channel estimation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If multiple RF chains are used to maintain consistent phase and magnitude in beam space MIMO, then signal consistency is improved, but device complexity increases
Solution Approach 1:
The patent changes the parameter of signal processing from RF domain to baseband domain. By performing channel estimation and compensation in the baseband domain rather than requiring multiple RF chains, the system achieves signal consistency with reduced hardware complexity. The baseband signal processing allows for effective compensation of phase and magnitude changes without needing multiple RF chains.
Solution Approach 2:
The patent replaces the mechanical/hardware solution of using multiple RF chains with a software-based baseband processing approach. Instead of physically replicating RF chains to maintain signal consistency, the system uses digital signal processing in the baseband domain to achieve the same goal, thereby reducing device complexity.
2Productivity
If the number of antennas is increased to maximize MIMO performance, then data rate is improved, but implementation complexity and system size increase
Solution Approach 1:
The patent segments the antenna system into active antenna elements and parasitic antenna elements. By using a small number of active elements (one or a few) combined with parasitic elements, the system achieves MIMO performance benefits without needing to increase the total number of antennas proportionally, thus reducing system complexity.
Solution Approach 2:
The parasitic antenna elements serve multiple functions: they act as both passive radiating elements and as part of the impedance tuning mechanism. This multi-functionality allows the system to achieve MIMO performance without requiring dedicated active elements for each spatial stream, thereby reducing overall system complexity.
3Measurement precision
If RF impairment compensation is performed with long cycle, then compensation accuracy is improved, but time efficiency deteriorates
Solution Approach 1:
The patent performs preliminary channel estimation and compensation setup in the baseband domain before actual data transmission. By pre-characterizing the channel and preparing compensation parameters in the baseband domain, the system can rapidly apply compensation without needing lengthy real-time adjustment cycles, thus improving time efficiency while maintaining accuracy.
Data Source
AI summary
A method and apparatus for modulating a baseband signal in beam space MIMO are provided. The baseband signal modulation apparatus may calculate a load value of a plurality of antenna elements using a baseband signal. The baseband signal modulation apparatus may change a phase or a magnitude of a baseband signal or a first band signal having a higher frequency than that of the baseband signal to correspond to the calculated load value.