NUST Hybrid (WDM/TDM) EPON based Access Network with Triple Play Support

摘要

Next generation services of triple play (data/voice/video) require far more bandwidth than existing technologies like dial-up, Integrated Services for Digital Network (ISDN), cable, Digital Subscriber Line (DSL) could offer. The gulf between the access and metro networks is widening due to bandwidth difference. This problem is termed as "access bottleneck". The challenge is to deliver triple play services efficiently and cost effectively. Passive optical network has addressed these challenges in a most promising manner. This paper presents an enhancement to our proposed hybrid (WDM/TDM) architecture by supporting triple play services. It employs Ethernet Passive Optical Network (EPON) within last mile to address the access bottleneck issue. It uses digital transmission for data and voice service. Analog video broadcast service is realized using Radio Frequency (RF) overlay model. Downstream is broadcast to Optical Network Units (ONUs) from Optical Line Terminal (OLT) whereas Time Division Multiple Access (TDMA) scheme is used for upstream. Hybrid (WDM/TDM) scheme allows that with growing bandwidth requirements, architecture can be scaled by adding WDM PONs with few modifications. Performance analysis of our proposed architecture using simulation technique shows that the signal power received at the farthest ONU after passing through a distance of 15km is -25dBm with a satisfactory bit error rate (BER) of 1.6282e-032 and a Signal to Noise Ratio (SNR) of 50dB for video service, indicating good and clear picture quality. Proposed hybrid approach not only fulfills the desired requirement for availing services of data/voice/video (triple play) but also achieves its objective cost effectively.