Passive optical network communication method, passive optical network communication system, optical network unit and optical line terminal

Abstract

The invention discloses a passive optical network (PON) communication method, which comprises the following steps: utilizing wavelength division multiplexing technology to generate a plurality of optical carrier groups of which the wavelengths are different from each other, wherein each optical carrier group comprises a plurality of optical carriers of which the wavelengths are the same; adoptingoptical code division multiple access (OCDMA) technology to perform code division on the carriers of each wavelength; changing user signals into a signal sequence with spread-spectrum characteristic through chaotic spread-spectrum processing; distinguishing different users according to an address code of an OCDMA system on each carrier; and recovering an original signal through related decoding and matching operations at a receiving end. The invention also discloses a PON system, an optical line terminal (OLT) and an optical network unit (ONU). By adopting the PON communication method, the PON communication system, the OLT and the ONU of the invention, the OCDMA is performed on the basis of wavelength division multiplexing, and the address code of the OCDMA system is generated by adoptingchaotic spread spectrum technology so that user capacity in the PON system is expanded.

Description

technical field [0001] The invention relates to optical access network technology, in particular to a passive optical network (PON) communication method and system, an optical network unit (ONU) and an optical line terminal (OLT). Background technique [0002] PON technology is currently the most ideal solution to solve the bandwidth bottleneck of the access network and realize fiber-to-the-home (FTTH). The current PON mainly includes two types, namely: a wavelength division multiplexing (WDM) PON and a time division multiplexing (TDM) PON. Among them, PON using wavelength division multiplexing can avoid technical difficulties such as ONU ranging and fast bit synchronization in time-division multiplexing PON, and has high bandwidth, protocol transparency, independent line rate, virtual point-to-point connection, and high security and easy upgradeability, therefore, wavelength division multiplexing PON is becoming more and more prominent in PON technology. [0003] However,...

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Problems solved by technology

[0003] However, due to the nonlinear phenomenon of optical fibers, when the number of wavelengths in the wavelength division multiplexing PON system reaches a certain threshold, the bottleneck of crosstalk between channels becomes particularly prominent, and the linear increase in the number of wavelengths will cause an exponential increase in cost. Therefore, , the number of available wavelengths of the current wavelength division multiplexing PON system is limited, because in the wavelength division multiplexing PON system, an optical signal of one wavelength is used for data transmission for one user, that is, different wavelengths are used to distinguish different users, so the limitation of the number of wavelengths makes it impossible for the current PON system to achieve large-capacity user access

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