Based On MIMO-OFDM United Technologies LED Visible Light Communication System Design

Because of its wide bandwidth, radiation safety and application breadth, Visible LED Communication (VLC) technology, has become beneficial supplement punctuate communications, and formed as a trend. In the near future, LED lighting is expected to be popular while the popularity of VLC indoor wireless data transmission can come true. VLC communication is via a high-speed electrical drive circuit flashing LED light source emits out. By a variety of techniques,the receiving side extracts the useful signal component from the complex interference to captture optical signal,which can achieve the dual purpose of the compatibility between lighting and communication.This paper presents that OFDM-MIMO can be applied in the designof VLC. High-speed stream of OFDM technology mapping algorithm by the FFT and IFFT low-speed serial to parallel orthogonal subcarriers, stream rate decreases significantly extended cycle makes multipath delay caused interference is very small, and because of the orthogonality allows the receiver each side can clearly be stripped and restored carrier signal. Furthermore, OFDM technology OFDM cyclic prefix to each symbol preceding. Cyclic prefix length greater than the maximum multipath delay, the success of restraint multipath effects.MIMO technology uses a multi-antenna transceiver techniques,using the principle of space division multiplexing, the multiplexed optical signal is simultaneously transmitted and received. This paper presents two2admission antenna array, compared with the traditional single-input single-antenna technology, channel utilization doubling channel capacity also becomes the original two-fold. MIMO MMSE detection algorithm is employed. Meanwhile, MIMO technology also takes advantage of spatial diversity principle. In the transmitter the source for STBC encoded data stream transmitted between the antenna orthogonal to each other, to reduce self-interference caused by multiple antennas brings coding gain.The optical design of the traditional mode of communication, only OFDM modulated optical communication mode, OFDM-MIMO technology combined optical communication mode, OFDM-MIMO technology combined with STBC encoded optical communication mode, these four modes through the line simulation. BER simulation curves show that the error rate performance under these four modes are sequentially delivered excellent.