Butler Matrix Beam Steering With Phase Shifters for mmWave Coverage
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Solution Overview
Problem
Current wireless communication systems, particularly in 5G NR, face challenges in optimizing beamforming for multi-antenna technologies to achieve efficient beam steering and coverage, especially in millimeter wave frequencies where path loss is high and beam angles need precise control.
Innovation Solution
The implementation of a Butler matrix with phase shifters and hybrid couplers in multi-antenna devices allows for the activation of input ports to generate signals with varying phase shifts, which are further phase-shifted by phase shifters, enabling beams with different angles and phase differences, thereby enhancing beamforming capabilities.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If traditional beamforming methods are used in multi-antenna systems, then system complexity is reduced, but beam steering precision and coverage control are insufficient, especially in millimeter wave frequencies
Solution Approach 1:
The beamforming system is segmented into multiple independent functional modules: Butler matrix for phase distribution, phase shifters for individual beam control, and hybrid couplers for signal combination. This segmentation allows precise beam steering through coordinated operation of discrete components while managing system complexity through modular architecture.
Solution Approach 2:
The system employs dynamic phase shifting capabilities where phase shifters can adjust phase differences in real-time based on activation signals. This dynamic control enables precise beam angle adjustment and steering without requiring physical movement of antenna elements, achieving high measurement precision through electronic control.
2Productivity
If millimeter wave frequencies are used to increase bandwidth, then data rate is improved, but path loss increases and coverage is reduced
Solution Approach 1:
The system changes the phase parameter of transmitted signals using Butler matrix and phase shifters to create directional beamforming. By dynamically adjusting phase differences across antenna elements, the system concentrates energy in specific directions to compensate for millimeter wave path loss, maintaining coverage reliability while operating at high frequencies for high data rates.
Solution Approach 2:
The Butler matrix and phase shifter configuration provides multi-functional capability: it enables both wide coverage through omnidirectional transmission modes and focused coverage through directional beamforming modes. This universal system adapts to different coverage requirements while maintaining millimeter wave operation for high productivity.
3Adaptability or versatility
If multiple input ports are activated in the Butler matrix, then beamforming versatility is improved, but signal phase control complexity increases
Solution Approach 1:
The Butler matrix acts as an intermediary device that automatically manages phase relationships between multiple activated input ports. It provides fixed phase shifts between its output ports, which simplifies the overall phase control complexity by offloading the complex phase management function to the passive Butler matrix structure rather than requiring active control for each signal path.
Solution Approach 2:
The Butler matrix pre-establishes specific phase relationships between its output ports through its fixed structural design. This preliminary phase configuration reduces the burden on active phase shifters, as they only need to make fine adjustments rather than managing all phase relationships from scratch, thereby reducing overall phase control complexity while maintaining versatility.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution improves beamforming efficiency and coverage by allowing for precise control of beam angles and phase differences, addressing the high path loss and coverage issues in millimeter wave frequencies, and is applicable to both UE and base station configurations.
Implementation Method 1
the Butler matrix is configured to receive at least one activation signal to activate one or more of the input ports and output signals from all of the output ports based on one or more activated input ports, wherein the signals output from the output ports have varying phase shifts relative to each other
Implementation Method 2
a plurality of phase shifters respectively coupled to the output ports of the Butler matrix and configured to respectively phase shift the signals output from the output ports, wherein the phase shifted signals have further varying phase shifts relative to each other and a phase difference between adjacent phase shifted signals
Data Source
AI summary
Aspects of disclosure relate to beam steering at a multi-antenna device. The device receives an activation signal to activate one or more input ports of a Butler matrix and outputs signals from all output ports of the Butler matrix based on activation of the one or more input ports. The signals output from the output ports have varying phase shifts relative to each other. Moreover, the device phase shifts the signals output from the output ports via a plurality of phase shifters respectively coupled to the output ports. The phase shifted signals have further varying phase shifts relative to each other and a phase difference between adjacent phase shifted signals. Each one of a plurality of antenna elements at the device receives a phase shifted signal from an associated phase shifter and outputs a beam based on the phase shifted signal received from the associated phase shifter.