Research On The Light Receiving Technology Of Indoor MIMO Visible Light Communication

As an environmental friendly lighting source,LEDs are widely used in our daily life.And researchers are looking for other new applications of LEDs.Because of the high modulation bandwidth,LEDs can be used in visible light communication technology.To satisfy the requirement of illumination,there must be many LEDs used in lighting.So it is easy to consider the combination of visible light communication and multiple input multiple output(MIMO)technology which is used in wireless communication.And with the introduction of MIMO,it is possible to get higher communication data rate and better performance.There are multiple LEDs acting as transmitters and multiple photodiodes acting as receivers in MIMO visible light communication system.Lights containing the message transfer from LEDs to photodiodes theoretically.Thus receiving technology in MIMO visible light communication system is vital in the whole systems.At the receiver,lights from different LEDs would be received by all the photodiode.And the signal should be separated at the receiver to recover the original transmitting signals easily.In this paper,the receiving technology will be studied.A novel receiver is proposed in this paper based on the angle diversity receiving technology for non-imaging receiver while a fish-eye lens is designed for imaging receiver.Then a 4×4MIMO communication system is established in MATLAB,and the comparision between these two kinds of receivers is giving based upon the channel capacity and SNR.A fish-eye lens is designed for imaging receiver whose field of view is 120°.Use ZEMAX to assist the lens design and give the estimation of image quality.At last,a two-lens non-imaging optical antenna is designed.And analyse the feasibility and suitability of using this fish-eye lens in imaging receiver.This optical antenna is verified by an experiment to have an effect on improving the field of view and communication quality.This optical antenna can also be used in the non-imaging receiver directly.An optical antenna can significantly improve the communication distance,the field of view of the receivers,and the seperation of different signals.A further research can be done around simplifying the stucture of the imaging optical antenna proposed in this paper and applying it in the practical engineering.