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Method for evaluating PAM-OFDM (Pulse-amplitude Modulation-Orthogonal Frequency Division Multiplexing) visible light communication system signal peak-to-average ratio

A technology of PAM-OFDM and visible light communication, which is applied in the field of evaluating the signal peak-to-average ratio of PAM-OFDM visible light communication system, which can solve the problems that complex signals cannot be used and achieve high accuracy.

Inactive Publication Date: 2017-06-13
SOUTHEAST UNIV
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Problems solved by technology

[0003] Different from the traditional wireless radio frequency communication system, the intensity modulation direct detection technology is commonly used in the visible light communication system. This is because in the visible light communication system, the luminous intensity is generally used to carry information, and the luminous intensity of the LED can only be is a non-negative real number, so complex signals cannot be used as in the traditional RF domain

Method used

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  • Method for evaluating PAM-OFDM (Pulse-amplitude Modulation-Orthogonal Frequency Division Multiplexing) visible light communication system signal peak-to-average ratio
  • Method for evaluating PAM-OFDM (Pulse-amplitude Modulation-Orthogonal Frequency Division Multiplexing) visible light communication system signal peak-to-average ratio
  • Method for evaluating PAM-OFDM (Pulse-amplitude Modulation-Orthogonal Frequency Division Multiplexing) visible light communication system signal peak-to-average ratio

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Embodiment Construction

[0031] like figure 1 and 2 As shown, a series of high-speed parallel bit streams are serially converted to multiple parallel low-speed data streams, and then the parallel low-speed data streams are pulse amplitude modulated (PAM) and the modulated symbols are added as the imaginary part of the signal to be transmitted, that is, the first The signal on the k-way subcarrier is S k =jA k , each subcarrier frequency domain signal of PAM-DMT satisfies conjugate symmetry, and its frequency domain frame structure is:

[0032]

[0033] After IFFT, the time domain signal s n It can be expressed as

[0034]

[0035] Note that the time domain signal of PAM-DMT has odd symmetry, namely:

[0036]

[0037] Therefore, zero-crossing clipping will not lose any information on the IFFT output signal of PAM-DMT. Therefore, the lower clipping of the PAM-DMT signal is zero-crossing clipping, and the upper clipping depends on the situation. The clipping process is:

[0038]

[003...

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Abstract

The invention discloses a method for evaluating PAM-OFDM (Pulse-amplitude Modulation-Orthogonal Frequency Division Multiplexing) visible light communication system signal peak-to-average ratio. The peak-to-average ratio obtained by the invention has high accuracy, and is verified with a theoretical calculating value obtained by the invention through system simulation, so that the theoretical calculating value obtained by the invention has fairly high accuracy when the subcarrier number is big enough. The peak-to-average ratio of a clipping signal obtained by the invention is simple and easy in calculation, and can be quickly obtained through recognizing power of a time-domain signal on each subcarrier after modulation and an upper and lower bound of clipping regarding to PAM-DMT with big enough subcarrier number instead of actual hardware measurement.

Description

technical field [0001] The invention relates to the technical field of wireless optical communication, in particular to a method for evaluating the signal peak-to-average ratio of a PAM-OFDM visible light communication system. Background technique [0002] LED lamps have many advantages such as long service life, energy saving, and high luminous efficiency, and are widely used in indoor lighting. In the future, they will gradually replace traditional fluorescent lamps and incandescent lamps, and become mainstream indoor lighting devices. Recent studies have shown that LED devices can also perform high-speed digital communication while illuminating, and indoor visible light communication systems based on LEDs have the advantages of low cost, high transmission rate, and good confidentiality. Therefore, it is considered an important Indoor wireless communication technology. Compared with the existing radio communication, indoor visible light communication has the advantages of...

Claims

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Application Information

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Patent Type & Authority Applications(China)
IPC IPC(8): H04B10/077H04B10/116
CPCH04B10/0775H04B10/116
Inventor 王家恒许洋凌昕彤梁霄赵春明
Owner SOUTHEAST UNIV
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