An Adaptive Compensation Method for Expanding the Usable Communication Band of LEDs

Abstract

An adaptive compensation method for extending the available communication frequency band of LEDs, comprising the following steps: powering on the device, initializing; configuring parameters; measuring the amplitude-frequency characteristic parameters of the LEDs; calculating the power pre-emphasis coefficient of each subcarrier of DCO-OFDM; Power allocation, limited output of the power amplifier; calculate the mean value and variance of the subcarrier power at the receiving end and send it to the transmitting end; judge whether the mean value and variance of the subcarrier power meet the range; add one to the number of subcarriers; judge the number of subcarriers used Whether the conditions are met, and decide whether to enter the next cycle; determine the maximum number of compensated subcarriers of the digital pre-emphasis device; readjust the DCO-OFDM parameters and perform normal communication. The invention pre-compensates the transmission signal under the limitation of the output power, optimizes the LED frequency response characteristics, has better compatibility and flexibility, and ensures the communication rate and quality of DCO-OFDM visible light.

Description

technical field [0001] The invention relates to the field of wireless optical communication, in particular to an adaptive compensation method for extending the available communication frequency band of LEDs. Background technique [0002] LED-based visible light communication has attracted much attention in the research field of short-distance high-speed communication due to its advantages of low cost, high security, and abundant available bandwidth resources. However, the available bandwidth of LED lights used to send optical signals is relatively low, generally below 6 MHz, which greatly restricts the transmission rate and performance of visible light communication. In order to use LEDs to realize short-distance high-speed communication, it is necessary to widen the bandwidth of LEDs. [0003] At present, the methods to realize LED bandwidth expansion are pre-emphasis compensation by means of hardware. At present, there are several solutions such as bridge T-shaped equaliz...

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Problems solved by technology

[0004] (1) The hardware circuit cannot be compensated in combination with the LED attenuation characteristics;

[0005] (2) The hardware compensation circuit cannot compensate the LED bandwidth according to the actual output power. Under the condition of a certain system output power, if the bandwidth compensation range is too large, the compensation effect is not obvious, but the average power of the in-band signal is reduced. , the signal-to-noise ratio decreases;

[0006] (3) The hardware circuit can only compensate for one or a certain type of LED, lacking flexibility and compatibility

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