Uplink and downlink transmission system based on single-wavelength orthogonal frequency division multiple access (OFDMA) passive optical network

Abstract

The invention discloses an uplink and downlink transmission system based on a single-wavelength orthogonal frequency division multiple access (OFDMA) passive optical network, relates to the technical field of optical communication and aims to reduce the system cost and increase the frequency spectrum utilization rate. The system comprises an optical line terminal, a far-end node and a plurality of optical network units, wherein optical line terminal comprises a laser, a data modulation unit and an uplink data receiving unit; the data modulation unit is used for modulating a downlink signal onto a lower sideband of an optical carrier signal generated by the laser; the uplink data receiving unit is used for demodulating an uplink signal; the far-end node is used for distributing a modulated downlink signal to the optical network units and forwarding modulated uplink signals output by the optical network units to the optical line terminal; and the optical network units demodulate the modulated downlink signal, separate out an optical carrier from the modulated downlink signal, modulate the uplink signals onto an upper sideband of the separated optical carrier and send the uplink signals to the far-end node. The system cost of the system is low.

Description

technical field [0001] The invention relates to optical communication technology, in particular to a technology based on a single-wavelength OFDMA passive optical network uplink and downlink transmission system. Background technique [0002] Passive Optical Network (PON), as a low-cost solution to fiber-to-the-home access terminals, is the mainstream direction of current access network technology research. [0003] Traditional asynchronous transfer mode passive optical network (ATM Passive Optical Network, APON), Ethernet passive optical network (Ethernet Passive Optical Network, EPON) and Gigabit Passive Optical Network (Gigabit Passive Optical Network, GPON) technologies are all The time-division multiple access technology adopted, the bandwidth is shared by users, and complex scheduling algorithms and framing techniques are required to support different types of services. Although the emerging Wavelength-Division-Multiplexing Passive Optical Network (WDM-PON) technology ...

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Problems solved by technology

However, this solution uses two separate light sources at the optical line terminal as the local oscillator light source for heterodyne coherent detection, which increases the cost of the optical line terminal to a certain extent, and does not make full use of the resources of the optical carrier, thus to a certain extent On the other hand, the passive optical network system loses the advantage of low cost, and the optical network unit (ONU) uses a radio frequency source to up-convert the baseband OFDM signal. The use of radio frequency sources will also increase the cost of the optical network unit (ONU)

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