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Dual-space modulation method for wireless optical communication

A technology of wireless optical communication and modulation method, which is applied in the field of wireless optical communication, can solve problems such as increased complexity, and achieve the effects of improving bit error performance, increasing spectral efficiency and transmission rate

Active Publication Date: 2019-10-11
LANZHOU UNIVERSITY OF TECHNOLOGY
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Problems solved by technology

[0007] The benefits of the present invention are: simultaneously activating two lasers to send PPM modulation and PAM modulation symbols respectively, which not only improves the spectral efficiency and transmission rate of the system, but also effectively improves the bit error performance of the system at the cost of a little complexity increase , and solve the problem that the number of lasers must be an integer power of 2

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  • Dual-space modulation method for wireless optical communication
  • Dual-space modulation method for wireless optical communication
  • Dual-space modulation method for wireless optical communication

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Embodiment Construction

[0009] The present invention is a dual-space modulation method for wireless optical communication. The transmitting end transmits pulse position modulation (PPM) and pulse amplitude modulation (PAM) respectively by simultaneously activating two lasers each time, and the activated lasers carry different information. The receiver adopts Maximum Likelihood Decoding (ML) to detect the signal; and adopts the joint bound technique to deduce the upper bound of the theoretical bit error rate of this method in the log-normal channel.

[0010] Concrete steps of the present invention are:

[0011] Step 1: Assume that the total number of lasers is N t , the number of lasers activated each time is 2, then from N t The number of combinations that activate 2 of the lasers is kind. Since the number of laser combinations used must be an integer power of 2, it is only necessary to start from Choose from a combination of species, among which, Indicates the rounding down operation.

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Abstract

The invention discloses a dual-space modulation method for wireless optical communication, and aims to establish the dual-space modulation method for wireless optical communication by utilizing PPM modulation and PAM modulation, thereby improving the transmission rate of a wireless optical communication system. According to the method, two lasers are activated at the same time each time to send pulse position modulation (PPM) and pulse amplitude modulation (PAM) respectively, and then the system transmission rate is increased. First, a transmitting end uses the characteristics of laser mappingvectors, M-PPM modulation symbols, and L-PAM modulation symbols to construct a transmission signal matrix. Then transmitted optical signals pass through a turbulence channel and then reach a receiving end to be received by an optical detector. On the premise of assuming the receiving end has known channel state information, namely, signal detection is performed by adopting a maximum likelihood decoding algorithm with known H to recover original bit information. On this basis, upper bound o theoretical bit error rate of the method under a logarithmic normal channel is derived by using joint bound technology.

Description

technical field [0001] The invention relates to a dual-space modulation method for wireless optical communication, which transmits pulse position modulation and pulse amplitude modulation respectively by activating two lasers at the same time each time, so as to improve the system transmission rate, and belongs to the technical field of wireless optical communication. Background technique [0002] Wireless optical communication has become a new type of broadband access technology because of its good confidentiality and excellent cost performance. With the rapid increase of data transmission traffic, people put forward higher requirements on the capacity and transmission rate of wireless optical communication systems; at the same time, the existence of atmospheric turbulence will seriously affect the effectiveness and reliability of wireless optical communication systems. Optical spatial modulation technology not only uses traditional digital modulation constellations (that i...

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Application Information

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IPC IPC(8): H04B10/2575H04B10/50H04B10/524H04B10/54
CPCH04B10/25752H04B10/503H04B10/524H04B10/54
Inventor 王惠琴杨顺信曹明华曹建锋王玺吕佳芸武鑫
Owner LANZHOU UNIVERSITY OF TECHNOLOGY