| Advance of the information process and the demands of network applications, drive thenetworks developing quickly. PON technology is to follow this trend and move towards themarket as a quality and cheap broadband access technology. Orthogonal Frequency DivisionMultiplexing (OFDM) technology makes the combination of multiple information channelswith a transmission, it matures and gradually developed a digital multi-carrier modulationtechnology along with the digital signal processing (DSP) technology, and it is usedin wireless communication systems mainly, can resist multi-path fading wireless channel andimprove the system spectrum efficiency. Compared with WDM-PON system, OFDM-PONcan provide a smaller granularity of bandwidth allocation, while the increased bandwidthwithout upgrading bandwidth transceiver, with a high split ratio.Orthogonal Frequency Division Multiplex (OFDM) has been successfully used inwireless communications, and now people begin to see it as an excellent candidate techniquein optical access networks. In this article, we first make comparison between OFDM basedpassive optical network (PON) and traditional PONs, and then review some previous workof OFDM PON. After that we introduce our physical layer scheme. In addition, networkarchitecture, MAC protocol and three dynamic bandwidth allocation (DBA) schedules thatoptimized for OFDM communication are recommended. At last, computer simulation resultsare given to demonstrate the performance of the three schedules.This paper analyzes the characteristics of mobile radio channel based on the basicprinciple of OFDM-PON system, and use a network simulation software named OPNETModeler to model and simulate OFDM-PON system from the network layer, then I analysisthe simulation results.Bandwidth of the OFDM-PON system is more fully utilized,simulation results can match with the actual system basically. The research result has alreadybeen published by Photonic Network Communication in U.S.A, as first author. |
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