VOOK-fused dimmable orthogonal hybrid ACO-OFDM method
An orthogonal mixing and dimming technology, applied in the field of wireless optical communication, which can solve the problems of low spectral efficiency, high receiver complexity and processing delay, and increased processing delay at the receiving end.
Active Publication Date: 2021-08-31
NANJING UNIV OF INFORMATION SCI & TECH +1
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Problems solved by technology
MPPM-RPO-OFDM adopts the method of signal polarity inversion to realize the integrated transmission of MPPM and asymmetrically limited optical OFDM (ACO-OFDM). However, since ACO-OFDM only uses half of the subcarriers to transmit information, the method Spectrum efficiency is relatively low
FRPO-OFDM uses the same principle to implement VOOK and layered ACO-OFDM (LACO-OFDM), but since LACO-OFDM needs to use serial interference cancellation for detection, the receiver complexity and processing delay are relatively high
In addition, in this type of technology, the receiving end needs to detect the variable modulation signal first, and then the subsequent OFDM signal detection can be performed, which further increases the processing delay at the receiving end, and at the same time causes the propagation of detection errors.
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[0054] In order to make the object, technical solution and advantages of the present invention clearer, the present invention will be described in detail below with reference to the accompanying drawings and specific embodiments.
[0055] figure 1 It is a block diagram of a dimmable orthogonal hybrid ACO-OFDM transmitter incorporating VOOK in the present invention, figure 2 It is a block diagram of an adjustable optical orthogonal hybrid ACO-OFDM receiver incorporating VOOK in the present invention.
[0056] Step 1: Generate frequency domain signals of ACO-OFDM and PAM-DMT. Perform QAM and PAM modulation on the two channels of transmitted data respectively to generate QAM and PAM symbols, and the l-th QAM symbol and the i-th PAM symbol are denoted as Q l and P i , where l=1,2,...,N / 4, i=1,2,...,N / 4-1. Then the generated symbols are serial-to-parallel converted, and according to the Hermitian symmetry, at the same time, the QAM symbols and PAM symbols are respectively load...
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The invention discloses a variable optical orthogonal hybrid ACO-OFDM method fusing VOOK, and relates to the field of optical communication. According to the method, the VOOK signal, the PAM-DMT signal and the ACO-OFDM signal are subjected to superposition transmission in the time domain, the dimming degree can be linearly adjusted by changing the duty ratio of the VOOK, and therefore the dual functions of efficient communication and dimming control are achieved. In the method provided by the invention, by constructing the time domain symmetry of the VOOK, the interference of the VOOK signal on the transmission of the PAM-DMT and the ACO-OFDM is avoided, and meanwhile, the transmission information is not lost after the clipping of the PAM-DMT and the ACO-OFDM. More importantly, the transmitting end adopts a preprocessing mode, so the orthogonality of two kinds of mixed signals of PAM-DMT and ACO-OFDM is ensured, and the interference between the two kinds of signals is eliminated. At a receiving end, in view of the orthogonality of the PAM-DMT and ACO-OFDM mixed signals, the detection of the two signals can be completed by adopting a standard OFDM receiver, and the complexity and the processing time delay of the receiver are effectively reduced. Meanwhile, parallel detection of VOOK and orthogonal mixed signals can be realized, and the processing time delay is further reduced; and higher reachable spectrum efficiency can be obtained.
Description
technical field [0001] The invention relates to the field of wireless optical communication, in particular to an adjustable optical orthogonal hybrid ACO-OFDM method integrating VOOK. Background technique [0002] With the increasingly tight frequency band of wireless radio frequency communication and the rapid development of light-emitting diode (LED) technology, visible light communication technology has attracted extensive attention from academia and industry. Visible light communication is built on the LED lighting system, which has many advantages such as green environmental protection, low cost, and no electromagnetic radiation. In addition to improving the performance of information transmission, the research on visible light communication technology in recent years also requires us to take into account the basic lighting function of LEDs. In LED lighting systems, dimming control can provide brightness adjustment according to user needs, which has the effect of savin...
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Login to View More IPC IPC(8): H04L25/03H04L27/26
CPCH04L25/03821H04L27/2601H04L27/2623
Inventor李宝龙陆波丁文杰邵永松周颖
OwnerNANJING UNIV OF INFORMATION SCI & TECH