说明：  对可见光通信的调制模块进行研究，并且对各种调制方案的调光功能进行了研究和比较。
(we propose a MPPM to offer both functions of modulating data-stream and controlling the brightness at the same time.From our studies, we show that MPPM is superior to variable on–off keying (VOOK) and variable pulse position modulation (VPPM) proposed in the IEEE 802.15 VLC task group.)