VLC Channel Allocation Using TDM and Wavelength Division
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Conventional Visible Light Communication (VLC) systems face limitations in providing diverse services when multiple adjacent light sources overlap, leading to interference and non-service areas, restricting the ability to offer different services to users and efficiently utilize light sources.
Innovation Solution
A method and apparatus for allocating channels in a VLC system using Time Division Multiplexing (TDM) and wavelength division multiplexing, where each user or service is allocated a specific time slot channel and wavelength channel, which can be dynamically changed based on service characteristics and environmental conditions, allowing for efficient data transmission and preventing interference by using non-adjacent wavelength bands.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Area of stationary object
If multiple adjacent light sources are installed to provide VLC service in a wide space, then the service coverage area is improved, but interference occurs in overlapping service areas and non-service areas are created
Solution Approach 1:
The service area is segmented into multiple zones, each served by a different light source using orthogonal codes. This allows simultaneous service in overlapping areas without interference by assigning unique code sequences to each light source, enabling spatial segmentation of the communication resource.
Solution Approach 2:
The patent introduces a new dimension for resource allocation by using orthogonal codes (code domain) in addition to traditional time and frequency domains. This allows multiple light sources to operate simultaneously in overlapping areas by assigning different code sequences, effectively adding a fourth dimension to the resource allocation space.
2Adaptability or versatility
If multiple light sources provide different services, then service diversity is improved, but data collision occurs in collision regions preventing regular service
Solution Approach 1:
Different services are segmented into distinct orthogonal code groups. Each service type (e.g., data transmission, control signals, multimedia) is assigned unique orthogonal codes, allowing simultaneous provision of diverse services in the same spatial region without data collision, as each service can be independently decoded using its assigned code.
Solution Approach 2:
The orthogonal code allocation system provides universal service capability across multiple light sources. The same code allocation mechanism can accommodate various service types (data, control, multimedia) and can be applied to any number of light sources, making the system universally adaptable to different service requirements while maintaining reliability.
3Area of stationary object
If conventional VLC is used with multiple light sources, then service coverage is improved, but all users must receive the same service limiting customization
Solution Approach 1:
The system applies local quality by assigning different orthogonal codes to different users or user groups in different spatial locations. Each user can receive customized service content through their assigned code, allowing service differentiation in overlapping coverage areas while maintaining broad geographic coverage through multiple light sources.
Data Source
AI summary
A method and apparatus for allocating resources of a Visible Light Communication (VLC) terminal in a VLC system. The VLC terminal receives a beacon message from a base station, coordinates time synchronization with the base station, searches for an available wavelength channel, constructs available wavelength channel information, and transmits an initial access request using a basic time slot channel and a basic wavelength channel. The base station considers the available wavelength channel information and a current channel allocation condition, allocates an appropriate channel, and transmits channel allocation information to the VLC terminal. The VLC terminal and the base station communicate data with each other using an allocated time slot channel included in the channel allocation information and an allocated wavelength channel included in the channel allocation information.