考虑远端用户随机位置的协作NOMA-VLC性能分析OA

To address the performance degradation issue in visible light communication(VLC)systems caused by dynamically changing user distribution and imperfect channel state information(CSI)feedback,a two-user cooperative non-orthogonal multiple access(NOMA)VLC system was investigated.A probability density function model of the channel gain was established based on the location distribution of the far user,and analytical expressions for the system bit error probability(BEP)were derived.On this basis,the performance of cooperative and non-cooperative systems was comparatively analyzed by incorporating the maximal ratio combining(MRC)technique.Simulation results demonstrate that,with the increase of signal-to-noise ratio(SNR)the cooperative system employing MRC significantly improves the system performance and effectively reduces the BEP.Among the considered modulation schemes,including L-pulse position modulation(PPM)and on-off keying(OOK),8-PPM achieves the best performance,followed by 4-PPM and OOK,while 2-PPM exhibits the poorest performance.Moreover,system performance improves as the outer-ring radius decreases,indicating that the outer-ring parameter has a more pronounced impact on coverage performance for dynamically distributed users.In addition,imperfect CSI leads to an increase in the error rate,highlighting the importance of accurate channel estimation.The proposed dynamic channel model and cooperative transmission scheme provide theoretical support for the application of NOMA-VLC systems in smart homes and industrial internet of things scenarios.