Light-emittingdiode（LED）-basedvisiblelightcommunication（VLC）hasbecomeapotentialcandidatefornextgenerationultra-high-speedindoorwirelesscommunication.Inthispaper,fourspecial-shaped8-quadratureamplitudemodulation（QAM）constellationsareinvestigatedinasingle-carrierVLCsystem.Itisnumericallyverifiedandexperimentallydemonstratedthatcircular（7,1）showsobvioussuperiorityintheperformanceofthedynamicrangeofsignalvoltagepeak-to-peak（vpp）valueandbiterrorrate（BER）.Nextbestisrectangular,followedbytriangular;circular（4,4）hastheworstperformance.Adatarateof1.515Gbit/sissuccessfullyachievedbycircular（7,1）employingaredchipLEDover0.5mindoorfreespacetransmissionbelowaBERthresholdof3.8×10-3.Comparedwithcircular（4,4）,thetraditional8-QAMconstellation,circular（7,1）providesawiderdynamicrangeofsignalvpp,ahigherdatarate,andalongertransmissiondistance.Tothebestofourknowledge,thisisthefirstinvestigationintotheperformancedifferencesofspecial-shaped8-QAMconstellationsinahighspeed,single-carrierVLCsystem,andtheresultscomprehensivelydemonstratethatcircular（7,1）istheoptimaloption.
