An Analysis For Visible Light Communication System Over Fading Channels

Wireless communication system has experienced several paradigm shifts starting from the discovery of electro-magnetic wave and the most popular frequency band is Radio Frequency(RF)since the introduction of cellular communication system.However,the available RF spectrum is rapidly dwindling along with increasing wireless network traffic since the demands of people for higher quality multimedia services.Fortunately,the emergence of Visible Light Communication(VLC)provides the new opportunities to wireless communications.Compared with RF communications,VLC is capable of achieving very high data rates and can also address the shortage of spectrum.Furthermore,VLC system can be deployed in some RF-restricted scenarios such airports or hospitals.There are many performance analysis of RF communication,such as outage probability,SNR and BER.However,researches are relatively rare in analysis of VLC systems.In this paper,a detailed performance analysis for VLC system over fading channels is derived.The main contributions of this paper include:(1)The closed-form bounds of outage probability of diversity combining systems over dual-branch non-identically distributed independent lognormal fading channels are derived.Analysing these bounds,we reveal that the imbalance between the channels' power has significant influence on the performance of diversity combining systems when the total receving power is fixed.(2)The closed-form bounds of outage probability of diversity systems over correlated lognormal fading channels have been derived.The bounds are optimized with respect to its parameters to ensure the tightness.Numerical results show that the proposed bounds are tight from low to high SNR regimes for arbitrary correlation.(3)We analysis the performance of diversity combining systems over N-branch identically distributed independent lognormal fading channels.Specifically,we derive the outage probability bounds of these kinds of diversity combining systems.We found that increasing the number of diversity branches will have a significant influence on the the performance of diversity systems.