THE YIN AND THE YANG OF A MOVE TO ALL FIBER: TRANSFORMING HFC TO AN ALL FIBER NETWORK WHILE LEVERAGING THE DEPLOYED HFC ASSETS

摘要

Many forward looking thinkers in the Cable industry believe that a move of HFC to an all fiber network is necessarily a move to a Passive Optical Network (G/EPON). However such a change would be quite disruptive and would bring with it challenges of maintaining two separate systems - one for the vast majority of customers now served by HFC and the other for those to be served by PON networks - for a very long time. For starters, only a small percentage of the total network could be converted to all fiber each year, even if all available resources are dedicated to this conversion activity alone. Furthermore, HFC traditionally has been cost effective because of large service group sizes per different offerings (HSD, VOD, VoIP), while PON link budgets generally limit one to far smaller service groups thus leading to much higher startup cost. What if there was a better way to go all fiber? This ideal way would enable the HFC and the all fiber systems to coexist, with the same equipment at the home and in the headends. It would enable MSOs to continue deployment and activation with the same set of tools and personnel. Finally it would provide a substantial increase in bandwidth, capacity and reliability to last the next several decades. Recent advances in RFoG technology enable just that. Now Cable MSOs can seamlessly migrate to an all fiber system while increasing capacity, conserving critical infrastructure and enhancing reliability. Why is now the right time? Up until now, a wider adoption of RFoG was severely limited by a particularly deleterious effect called Optical Beat Interference (OBI). Even very modest amounts of OBI have a severe effect on not only the upstream throughput but on the downstream throughput as well. Recent advances in technology have enabled the complete elimination of OBI thereby unlocking the true potential of fiber. In this paper, we provide critical insights into the innovations that enable OBI Free RFoG transmission. We will the discuss intrinsic capabilities of what we call Hybrid PON (HPON) technology, explain how this technology works with existing HFC analog and QAM video and D3.0 and D3.1 signals while also being completely transparent to the myriad of traditional PON standards such as the 10G EPON, 1G EPON, GPON and XGPON1.