Visible light multi-user time division multiplexing multiple access transmission method and system

Abstract

The invention discloses a visible light multi-user time division multiplexing multiple access transmission method and system. The method comprises the steps that a visible light communication lamp sends a downlink data signal; user terminals lockdownlink data signals through a phase-locked loop and extractcarrier wav; the visible light communication lamp broadcasts downwards and sends an access invitation instruction; the user terminals respectively receive the access invitation instruction, apply for network access through an uplink in a random multiple access mode, and report own time division occupancy coefficients; the visible light communication lamp collects the network access application, determines the number of downlink carrier cycles of each user terminal according to the numberof the user terminals, and issues the number of downlink carrier cycles of all the user terminals through a downlink; the user terminals respectively receive own downlink carrier cycle numbers; the visible light communication lamp sends a communication starting instruction; and the user terminal receives the communication starting instruction and performs time division multiplexing communication based on the downlink carrier cycle number of the user terminal. According to the invention, synchronous seamless switching among a plurality of user terminals is realized, and the transmission efficiency is effectively improved.

Description

technical field [0001] The present invention relates to the technical field of visible light communication, in particular to a visible light multi-user time division multiplexing multiple access transmission method and system. Background technique [0002] Visible light communication technology has outstanding advantages such as green, high efficiency, and ubiquitous, and is very suitable for indoor communication. A typical visible light indoor communication scenario includes multiple visible light communication lights as wireless connection points, and each light irradiation area contains multiple mobile visible light user terminals. Each visible light communication light and the user terminals in its irradiation area constitute a two-way one-to-many system. A common implementation method is: the downlink sends a communication light signal in the form of broadcast by a visible light communication light, and the user terminal receives the same signal and extracts the inform...

AI Technical Summary

Problems solved by technology

[0003] For this reason, the user terminal must first send pilot information after turning on the sending light. It is estimated that the useful data can only be sent after the upper loop of the visible light communication light is locked. A large guard interval needs to be left, resulting in low transmission efficiency.

If the guard interval is too small, it will cause packet loss

Images