基于MIMO-OFDM联合技术LED可见光通信系统设计
发布时间：2018-11-16 17:18
【摘要】：可见光LED通信(VLC)技术由于其超宽的带宽、辐射安全性及应用广泛性,已逐渐成为断句通信的有利补充,并已形成为一种发展趋势。期望不久的将来,LED照明普及的同时VLC在室内无线数据传输方面也能够普及。VLC通信是通过驱动电路将电信号通过高速闪烁的LED光源发射出去的。接收端捕捉这些光信号,通过多种技术手段,从纷繁复杂的干扰中提取有用的信号分量,实现兼容照明与通信的双重目的。 本文提出了将OFDM-MIMO联合技术应用在可见光通信系统的设计。OFDM技术通过IFFT及FFT算法将串行的高速码流映射为并行的低速正交子载波,码流速率降低,周期大幅延长使得多径时延带来干扰非常小,又由于正交性使得接收端可以清楚的将每个载波信号剥离并还原。另外,OFDM技术对每个OFDM符号前段添加循环前缀。循环前缀长度大于最大多径时延,成功的克制了多径效应。 MIMO技术采用了多天线收发的技术,利用空分复用的原理,同时收发多路光信号。本文设计了2发2收天线阵列,与传统的单发单收天线技术相比,信道的利用率提高一倍,信道容量也变为原来的2倍。采用的MIMO的检测为MMSE算法。同时,MIMO技术同时也利用了空间分集原理。在发射端对信源进行STBC编码,天线间发射的数据流彼此正交,减少多天线带来的自干扰,带来了编码增益。 本设计针对传统的光通信模式、仅有OFDM调制的光通信模式、OFDM-MIMO联合技术的光通信模式、带有STBC编码的OFDM-MIMO联合技术的光通信模式,这四种模式经行仿真。仿真误码率曲线表明这四种模式下误码率的表现是依次递优的。
[Abstract]:Because of its wide bandwidth, radiation safety and wide application, (VLC) technology of visible light LED communication has gradually become a favorable supplement to break sentence communication, and has become a trend of development. It is expected that in the near future, LED lighting will be popularized, while VLC will be able to popularize indoor wireless data transmission. VLC communication emits electrical signals through high speed flicker LED light source through driving circuit. The receiver captures these optical signals and extracts the useful signal components from the complex interference by a variety of technical means to achieve the dual purpose of compatible lighting and communication. In this paper, the design of the application of OFDM-MIMO technology in visible light communication system is presented. The OFDM technology maps the serial high speed bitstream into a parallel low speed orthogonal subcarrier by IFFT and FFT algorithm, which reduces the bitstream rate. The extended period makes the interference of multipath delay very small, and because of the orthogonality, the receiver can clearly peel off and restore each carrier signal. In addition, OFDM technology adds a cyclic prefix to the front of each OFDM symbol. The cyclic prefix length is larger than the maximum multipath delay and the multipath effect is successfully restrained. The MIMO technology adopts the technology of multi-antenna transceiver and uses the principle of space-division multiplexing to transmit and receive multi-channel optical signals at the same time. In this paper, two transmit and two receive antenna arrays are designed. Compared with the traditional single transmit and single receiving antenna technology, the channel utilization ratio is doubled and the channel capacity is doubled. The detection of MIMO is MMSE algorithm. At the same time, MIMO technology also makes use of spatial diversity principle. The source is coded by STBC at the transmitter, and the data streams transmitted between the antennas are orthogonal to each other, which reduces the self-interference caused by the multiple antennas and brings the coding gain. This design aims at the traditional optical communication mode, only the optical communication mode of OFDM modulation, the optical communication mode of OFDM-MIMO joint technology, the optical communication mode with STBC coded OFDM-MIMO joint technology, and the simulation of these four modes. The simulation results show that the performance of BER in these four modes is sequentially superior.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1
本文编号：2336132
[Abstract]:Because of its wide bandwidth, radiation safety and wide application, (VLC) technology of visible light LED communication has gradually become a favorable supplement to break sentence communication, and has become a trend of development. It is expected that in the near future, LED lighting will be popularized, while VLC will be able to popularize indoor wireless data transmission. VLC communication emits electrical signals through high speed flicker LED light source through driving circuit. The receiver captures these optical signals and extracts the useful signal components from the complex interference by a variety of technical means to achieve the dual purpose of compatible lighting and communication. In this paper, the design of the application of OFDM-MIMO technology in visible light communication system is presented. The OFDM technology maps the serial high speed bitstream into a parallel low speed orthogonal subcarrier by IFFT and FFT algorithm, which reduces the bitstream rate. The extended period makes the interference of multipath delay very small, and because of the orthogonality, the receiver can clearly peel off and restore each carrier signal. In addition, OFDM technology adds a cyclic prefix to the front of each OFDM symbol. The cyclic prefix length is larger than the maximum multipath delay and the multipath effect is successfully restrained. The MIMO technology adopts the technology of multi-antenna transceiver and uses the principle of space-division multiplexing to transmit and receive multi-channel optical signals at the same time. In this paper, two transmit and two receive antenna arrays are designed. Compared with the traditional single transmit and single receiving antenna technology, the channel utilization ratio is doubled and the channel capacity is doubled. The detection of MIMO is MMSE algorithm. At the same time, MIMO technology also makes use of spatial diversity principle. The source is coded by STBC at the transmitter, and the data streams transmitted between the antennas are orthogonal to each other, which reduces the self-interference caused by the multiple antennas and brings the coding gain. This design aims at the traditional optical communication mode, only the optical communication mode of OFDM modulation, the optical communication mode of OFDM-MIMO joint technology, the optical communication mode with STBC coded OFDM-MIMO joint technology, and the simulation of these four modes. The simulation results show that the performance of BER in these four modes is sequentially superior.
【学位授予单位】：华东理工大学
【学位级别】：硕士
【学位授予年份】：2014
【分类号】：TN929.1
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