In April 2023,a satellite orbiting approximately 500 km above Earth’s surface delivered terabytes of data at record-breaking rates of up to 200 Gb·s^(-1)—more than 100 times faster than the fastest internet spe...In April 2023,a satellite orbiting approximately 500 km above Earth’s surface delivered terabytes of data at record-breaking rates of up to 200 Gb·s^(-1)—more than 100 times faster than the fastest internet speeds in most cities—via an optical communication link to a ground-based receiver 95 km north of Los Angeles,CA,USA[1].At more than 1000 times faster than the radiofrequency(RF)links traditionally used for satellite communication,this is the highest data rate ever achieved for a space-to-ground optical transmission[1].展开更多
通过采用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术,实现了高速数据流的高效并行传输。通过自适应调制技术的动态调整能力,以响应信道状态信息(Channel State Information,CSI)的变化,从而在光纤传输中对抗...通过采用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术,实现了高速数据流的高效并行传输。通过自适应调制技术的动态调整能力,以响应信道状态信息(Channel State Information,CSI)的变化,从而在光纤传输中对抗色散和非线性效应等影响,优化系统性能。本研究提出基于深度神经网络(Deep Neural Networks,DNN)的自适应调制方案,通过实时监测子载波的有效信噪比(Signal to Interference plus Noise Ratio,SNR),动态调整比特分配和调制格式,以适应变化的信道条件。仿真结果表明,与固定调制格式相比,所提出的自适应调制方案在相同系统速率下显著降低了误码率,同时在不同误码率目标下均实现光信噪比的增益。展开更多
文摘5G新技术应用于可见光通信(Visible Light Communication,VLC)场景对系统容量以及频谱效率有了更高的要求,稀疏码多址接入(Sparse Code Multiple Access,SCMA)技术作为一种新型的非正交多址接入(Non-Orthgonal Multiple Access,NOMA)技术可作为解决方案。针对上述方案,搭建了VLC-SCMA系统,使得系统在相同的频谱资源下能够拥有更大的系统容量和频谱效率,同时为了降低系统复杂度,加快接收端进行多用户检测时的收敛速度,提出了基于串行改进下的部分外部信息传递的消息传递算法(Message Passing Algorithm Based on Serial Strategy for Partial External Information Transmission,SPEIT-MPA)。通过在迭代过程中设置门限值过滤掉携带信息量较少的外部信息点,利用串行改进使得算法迭代过程进一步简化。在VLC-SCMA系统中的仿真结果表明,对比原始算法,新算法可以在保证误码率(Bit Error Rate,BER)性能损失较少的前提下拥有更快的收敛速度,且算法复杂度随着信噪比(Signal to Noise Ratio,SNR)的增大明显降低。
文摘In April 2023,a satellite orbiting approximately 500 km above Earth’s surface delivered terabytes of data at record-breaking rates of up to 200 Gb·s^(-1)—more than 100 times faster than the fastest internet speeds in most cities—via an optical communication link to a ground-based receiver 95 km north of Los Angeles,CA,USA[1].At more than 1000 times faster than the radiofrequency(RF)links traditionally used for satellite communication,this is the highest data rate ever achieved for a space-to-ground optical transmission[1].
文摘通过采用正交频分复用(Orthogonal Frequency Division Multiplexing,OFDM)技术,实现了高速数据流的高效并行传输。通过自适应调制技术的动态调整能力,以响应信道状态信息(Channel State Information,CSI)的变化,从而在光纤传输中对抗色散和非线性效应等影响,优化系统性能。本研究提出基于深度神经网络(Deep Neural Networks,DNN)的自适应调制方案,通过实时监测子载波的有效信噪比(Signal to Interference plus Noise Ratio,SNR),动态调整比特分配和调制格式,以适应变化的信道条件。仿真结果表明,与固定调制格式相比,所提出的自适应调制方案在相同系统速率下显著降低了误码率,同时在不同误码率目标下均实现光信噪比的增益。
