针对水下可见光像素化多输入多输出(MIMO)系统中信道的吸收散射和接收透镜模糊引起的高频衰减带来部分子载波误比特数高的问题,提出一种基于可见光像素化MIMO系统的比特加载自适应算法。该算法在保证全部子载波待分配总比特数不变的前提下,根据不同子载波上的信噪比动态选择最优的子载波调制阶数,从而降低不同子载波误比特数,提升系统的可靠性。仿真结果表明,在像素化MIMO系统传输速率不变的条件下,本文算法大幅降低了误码率。

An adaptive bit loading algorithm is proposed based on visible-light pixelated multiple-input and multiple-output (MIMO) systems to deal with the problem of high number of bit errors for some subcarriers caused by the high-frequency attenuation, which is attributed to the absorption and scattering of channels and lens blur in underwater visible-light pixelated MIMO systems. By ensuring that the total number of bits allocated across all the subcarriers remains constant, the proposed algorithm dynamically selects the optimal subcarrier modulation order according to the signal-to-noise ratios of the subcarriers to reduce the number of bit errors for each subcarrier and improve the system reliability. The simulation results denote that the bit error rate can be considerably reduced when the transmission rate of the pixelated MIMO system is maintained constant.