Virtualized PON based on abstraction, softwarization, and service chaining for flexible and agile service creations [Invited]

The specifications of passive optical network (PON) systems continue to evolve while access systems need to accommodate an ever-widening variety of new services. To deal with the various requests, virtualization is essential for optical access networks. So far, optical line terminal (OLT) abstraction technology, represented by software-defined-network-enabled broadband access, has been commercialized as a platform, but a remaining challenge is the softwarization of media access control and physical-layer (PHY) processing as OLT functionalities. However, in the virtualized PON, service chaining (SC) is also crucial to realize efficient access networks that meet user requirements by chaining the virtualized functions. In particular, no study, to our knowledge, has focused on PHY SC classification that supports adaptive coding and modulation. This paper reviews recent advances in PON virtualization techniques including abstraction and softwarization while showing our target optical access system, which is fully virtualized. Furthermore, it proposes an SC classifier adopting low-complexity modulation format identification (MFI). Experiments show that our proposed method achieves 100% identification accuracy if the bit error rate is within the forward error correction limit; real-time processing speed of 2.5 Gsymbols/s with 3% computation resource occupancy is achieved, as the proposal has much lower computation overheads than other MFI methods.