Li-Fi Interference Management via Time Slot Scheduling
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Solution Overview
Problem
Current Light Fidelity (Li-Fi) communication networks lack mechanisms to manage interference caused by overlapping white light modulated access points, leading to connectivity issues when users move between access points, as they do not detect physical cell IDs or schedule data transmission effectively in interference regions.
Innovation Solution
A method and system that utilize an interference management device to detect User Equipment (UE) presence in interference regions by analyzing uplink data frames, attach the UE to the Li-Fi access point with the highest Channel Quality Indication (CQI), and schedule data transmission in mutually exclusive time slots to minimize interference.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple Li-Fi access points transmit data simultaneously in overlapping regions, then coverage area is expanded, but interference between access points increases causing data reception failures
Solution Approach 1:
The patent implements periodic action by introducing time slots for data transmission. Each access point transmits data in designated time slots rather than continuously, allowing other access points to transmit during different slots. This periodic transmission pattern eliminates simultaneous transmissions in overlapping regions, reducing interference while maintaining expanded coverage area through coordinated multi-access point operation.
2Adaptability or versatility
If users move between access points, then mobility is enabled, but connectivity is lost when entering interference regions
Solution Approach 1:
The patent applies preliminary action by having access points transmit beacon frames before actual data transmission. These beacon frames are sent in advance to allow mobile users to detect the presence of multiple access points and their respective time slots before the user actually needs to receive data. This preliminary beacon transmission enables users to prepare for handover and maintain connectivity when moving between access points, even when entering interference regions.
Solution Approach 2:
The patent implements feedback mechanisms where users send acknowledgment signals back to access points based on received beacon frames and data transmissions. This feedback loop allows the system to detect when a user is in an interference region and automatically adjust transmission parameters or switch to alternative access points, maintaining connectivity during mobility transitions.
3Difficulty of detecting and measuring
If beacon frames are transmitted to discover devices, then device discovery is enabled, but no existing mechanism exists to transmit beacons in interference regions
Solution Approach 1:
The patent extends periodic action to beacon frame transmission by implementing time slot-based beacon sending. Each access point transmits beacon frames in designated time slots, allowing beacon discovery to occur even in interference regions where multiple access points operate simultaneously. This structured periodic beacon transmission enables device discovery without requiring complex coordination mechanisms, as the time slot structure naturally prevents beacon collisions.
Data Source
AI summary
A method and system for managing interference between a set of Light Fidelity (Li-Fi) access points is disclosed. The method includes receiving a plurality of uplink data frames. Each of the plurality of uplink data frames includes a response that includes one of an Acknowledgement (ACK) and a Negative Acknowledgment (NACK) for the associated downlink test frame and a Channel Quality Indication (CQI) for the associated Li-Fi access point. The method further includes detecting presence of the User Equipment (UE) in an interference region of the set of Li-Fi access points. The method includes attaching the UE with a first Li-Fi access point having the highest CQI and scheduling data transmission from the set of Li-Fi access points in a mutually exclusive time slot. The UE accepts data received from the attached Li-Fi access point and drops data received from remaining set of Li-Fi access points.