Theory And Technology Of Optical Wireless Communication Using Spatial Modulation

With rich spectrum resources,high security as well as the properties of energy conservation and environmental protection,optical wireless communication(OWC)is becoming a new wireless communication technology attracting extensive attention,which combines the two functions of illumination and communication.It utilizes the light emitting diodes(LEDs)to transmit data.This thesis focuses on the channel capacity of OWC system using spatial modulation and studies the upper and lower bound of it,respectively.This thesis reseach the adaptive modulation’s utilization in the OWC system using spatial modulation.The research results can further fulfill the theory of visible light communications.Since there exists essential difference between the visible light communications and traditional wireless radio frequency communication,the signal of OWC is unipolar,the basic principles and results of radio frequency communication cannot be used in the area of OWC directly.It is necessary to research related OWC problems.There is lacking of OWC channel capacity and the utilization’s in OWC in the open literatures.This thesis analies and compare several spatial modulation technology:space shift keying(SSK),generalized space shift keying(GSSK),spatial modulation(SM),generalized spatial modulation(GSM).Spatial modulation modulate the data bits into signal domain and space domain.In signal domain,Pulse Amplitude Modulation(PAM)is a common choice amd modulated signal is mapped to constellation point.In space domain,data bits transmitted by the index of active LED,which improve the spectrum efficiency.The OWC system using spatial modulation is not impacted by the interchannel interference(ICI).It is also unnecessary for OWC system to synchronize the transmitting LED.The complexity of system is lowered.This thesis reseaches the channel model of the OWC system using SM thechnology and drives the channel capacity.At first,the OWC system is divided into multiple-input single-output(MISO)sytem and multiple-input multiple-output(MIMO)sytem.The lower bound of channel capacity is drived by data-processing inequality and the upper bound is drived under the assumption that the receiver can detect the index of the active LED correctly.This thesis reseaches the utilization of adaptive modulation in the OWC system and two schemes are proposed which are optimal and suboptimal respectively.