一种新的叠加64QAM星座设计方案

A Novel Superimposed 64QAM Constellation Design Scheme

为了提升可见光通信系统的传输速率和克服信道相关性,在2×2多输入多输出可见光通信系统中提出一种叠加64阶正交幅度调制(64QAM)星座方案。首先,在发射端生成两路几何整型的8QAM信号,通过两个发光二极管(LED)发送;其次,在自由空间传输到接收端线性叠加得到一个方形的64QAM星座信号。实验表明,所提方案误码率更低、电压峰峰值工作范围更广,相较于现有方案的发射端信号具有更大的最小欧式距离和较低的峰均功率比值,因此抗噪声能力更强,能有效降低发射端LED产生非线性失真风险。理论仿真和实验都证明了其优越性。

In order to improve the transmission rate of visible light communication systems and overcome channel correlation,a superimposed 64 order orthogonal amplitude modulation constellation scheme is proposed in a 2×2 multi input multi output visible light communication system.Firstly,generate two geometrically integer 8QAM signals at the transmitting end and send them through two light-emitting diodes;Then,a square 64QAM constellation signal is obtained by linearly superimposing the free space transmission to the receiving end.Experiments have shown that the proposed scheme has a lower bit error rate,a wider range of peak to peak voltage operation,and a larger minimum Euclidean distance and lower peak to average power ratio compared to existing schemes.Therefore,it has stronger noise resistance and can effectively reduce the risk of nonlinear distortion in the transmitting LED.Both theoretical simulations and experiments have proven its superiority.