Digital Beamforming Antenna Array with Low-Resolution DACs
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Solution Overview
Problem
High-speed, high-resolution digital-to-analog converters (DACs) in large antenna array systems consume significant power and either result in high power consumption or limited spatial duplexing capabilities, while analog beam-forming methods lack amplitude control and require complex calibration.
Innovation Solution
An antenna arrangement using low-resolution DACs with a de-correlator and dithering units to reduce power consumption and enhance spatial resolution, allowing for more flexible beam-forming and reduced interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If high-resolution DACs are used in each antenna branch, then accurate amplitude and phase control is achieved, but power consumption increases significantly
Solution Approach 1:
The patent segments the beam-forming function into digital and analog domains. Digital beam-forming weights are applied in the digital domain before DAC conversion, while analog phase-shifters handle phase adjustment after conversion. This segmentation allows lower-resolution DACs to be used since the digital precoder pre-processes the signals, reducing the burden on individual DACs while maintaining overall system precision.
Solution Approach 2:
The patent changes the resolution parameter of DACs from high (e.g., 12-16 bits) to low (e.g., 4-8 bits) in large antenna arrays. By combining multiple low-resolution DAC outputs with analog phase-shifters and digital precoding, the system achieves equivalent or superior performance to high-resolution DACs while dramatically reducing power consumption and chip area.
2Use of energy by moving object
If analog phase-shifters are used for beam-forming, then power consumption is reduced, but amplitude control capability is lost
Solution Approach 1:
The patent merges digital and analog beam-forming techniques into a hybrid architecture. Digital precoders provide amplitude control in the digital domain, while analog phase-shifters handle phase adjustment in the analog domain. This combination allows the system to achieve both amplitude and phase control capabilities while using power-efficient analog components for the majority of the beam-forming operation.
3Measurement precision
If high-resolution DACs are used, then signal fidelity is maintained, but chip area and cost increase
Solution Approach 1:
The patent applies partial digital beam-forming processing before DAC conversion, rather than requiring full high-resolution digital processing throughout the entire signal chain. The digital precoder applies weighting coefficients with sufficient precision, and the remaining precision requirements are met by the combination of multiple antenna elements and analog phase-shifters, allowing each individual DAC to operate at lower resolution.
Data Source
AI summary
An antenna arrangement configured for digital beam-forming of a transmit signal comprising; a number N>1 of digital to analog converters, DACs, each of the N DACs being arranged to receive one respective digital transmit signal component, and to convert and output an analog transmit signal component, each of the N DACs having a respective resolution below a resolution required to fulfill a regulatory radio requirement in an interchangeable antenna arrangement arranged for transmission by a single antenna element connected to a single DAC; and N antenna elements, each of the N antenna elements being configured to receive one respective analog transmit signal component and to transmit the analog transmit signal component as part of the digitally beam-formed transmit signal.