RIS Multi-Beam Design for mmWave Blind Spot Coverage
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Solution Overview
Problem
Millimeter wave (mmWave) communications face challenges with high free-space path-loss and poor scattering, resulting in mostly line-of-sight channels and coverage gaps, particularly in blind spots due to shadowing and blockage, which existing technologies like beamforming struggle to fully address.
Innovation Solution
A reconfigurable intelligent surface (RIS) is positioned as a uniform planar array to reflect signals, enabling the creation of sharp and effective multi-beams with controlled phase and gain, covering different solid angles and extending coverage to previously blind areas with low computational complexity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If beamforming is used to address high path-loss, then signal strength is improved, but coverage gaps in blind spots remain
Solution Approach 1:
The patent introduces a reconfigurable intelligent surface (RIS) as an intermediary component between the transmitter and receivers. The RIS reflects and shapes mmWave signals to cover blind spots that traditional beamforming cannot reach, effectively acting as a mediator to extend coverage while maintaining signal strength through cooperative beamforming.
2Area of stationary object
If reconfigurable intelligent surface is deployed to extend coverage, then coverage area is improved, but system complexity increases
Solution Approach 1:
The patent segments the coverage area into different spatial regions and uses multiple discrete elements of the RIS to independently shape beams for different regions. This segmentation allows the system to extend coverage to blind spots while managing complexity through modular, distributed beamforming across multiple RIS elements.
3Area of stationary object
If multiple beams are generated to cover different solid angles, then coverage area is improved, but computational complexity increases
Solution Approach 1:
The patent employs preliminary beamforming design where the RIS configuration and beam patterns are pre-optimized for different spatial regions. This preliminary action reduces real-time computational complexity by preparing beamforming weights and patterns in advance, enabling rapid switching between different beam configurations to cover various solid angles without excessive computational overhead.
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
The RIS effectively enhances mmWave channel coverage by generating high-gain beams within desired angular intervals, improving communication for users in blind spots while maintaining energy efficiency and reducing operational costs.
Implementation Method 1
positioning a reconfigurable intelligent surface (RIS) in a vicinity of the multi-antenna transmitter and the multi-antenna receiver, the RIS reflecting signals received from the multi-antenna transmitter toward the multi-antenna receiver
Data Source
AI summary
A method for shaping a mmWave wireless channel in a wireless network is presented. The method includes enabling communication between a multi-antenna transmitter and a multi-antenna receiver, positioning a reconfigurable intelligent surface (RIS) in a vicinity of the multi-antenna transmitter and the multi-antenna receiver, constructing the RIS as a uniform planar array (UPA) structure forming a multi-beamforming framework, a surface of the UPA defining an array of discrete elements arranged in a grid pattern, wherein parameters of the discrete elements of the UPA are controllable to achieve multiple disjoint beams covering different solid angles, and enabling the plurality of users of the plurality of mobile devices positioned in blind spots of a coverage map to communicate with the multi-antenna transmitter by employing the MS to generate sharp and effective beams having almost uniform gain in a desired angular coverage interval (ACI).