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Truncation compensation OFDM modulation method for wireless optical communication system

A technology of wireless optical communication and modulation method, which is applied in the field of optical communication, can solve the problems such as no compensation and correction methods are proposed, and achieve the effect of reducing truncation error and improving utilization rate

Inactive Publication Date: 2021-11-05
NORTHWESTERN POLYTECHNICAL UNIV
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Problems solved by technology

However, for the high peak-to-average ratio of the OFDM signal and the peak truncation error of the signal, no simple and effective compensation and correction method has been proposed.

Method used

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  • Truncation compensation OFDM modulation method for wireless optical communication system
  • Truncation compensation OFDM modulation method for wireless optical communication system
  • Truncation compensation OFDM modulation method for wireless optical communication system

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specific Embodiment

[0093] In IM / DD systems, the forward current signal drives laser diodes and other light sources as emission sources. Due to the structure of the laser diode, there is a nonlinear relationship between the output optical power and the input current. Due to current saturation, the maximum output optical signal of the LD will be affected by the peak power limit, and this will cause truncation noise in the modulated signal. Such as Figure 4 As shown, when transmitting multi-level or continuous-valued signals in an IM / DD system, the nonlinearity of the light source can cause distortion.

[0094] CEO-OFDM transmits non-negative real number signals by sequentially transmitting positive, negative and truncated information of bipolar OFDM signals. At the receiver end, this embodiment will reconstruct the received signal, so as to restore the original OFDM signal and realize the compensation for the truncation error.

[0095] The basic principle of CEO-OFDM is as follows: Figure 5 ...

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Abstract

The invention discloses a truncation compensation OFDM (Orthogonal Frequency Division Multiplexing) modulation method for a wireless optical communication system. According to the method, on the basis of U-OFDM, a signal part which should be limited and cut off by peak power is sent again by adding one or more transmission time slots, and a received signal is reconstructed at a receiving end; therefore, the peak truncation error of the OFDM signal is compensated and corrected. Under the condition that the transmitting power of the light source is limited, the utilization rate of the power is effectively improved and the truncation error of the signal is reduced by using a method of sending the truncation information in a time-sharing manner.

Description

technical field [0001] The invention belongs to the technical field of optical communication, and in particular relates to a truncation compensation OFDM modulation method. Background technique [0002] Intensity modulation and direct detection (IM / DD) communication systems such as free-space optical communication, visible light communication, and infrared communication have attracted much research attention in recent years. Using light-emitting diodes (LEDs) or laser diodes (LDs) as transmitters, IM / DD optical systems have many advantages over ratio-frequency (RF) communications, including high privacy, high data rates, low power consumption, and no spectrum adjust. However, since the signals sent and received must be non-negative real numbers in the IM / DD process, it is necessary to design the modulation mode when performing signal modulation in such communication systems. [0003] Because OFDM technology has the advantages of high transmission efficiency, no intersymbol...

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04L27/26H04B10/516
CPCH04L27/2614H04L27/2634H04B10/5161H04L27/2697
Inventor 廉杰廉殿斌汤宸聪高妍
Owner NORTHWESTERN POLYTECHNICAL UNIV
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