Silvano Frigerio

Next generation sliceable bandwidth variable transponders

This article reports the work on next generation transponders for optical networks carried out within the last few years. A general architecture supporting super-channels (i.e., optical connections composed of several adjacent subcarriers) and sliceability (i.e., subcarriers grouped in a number of independent super-channels with different destinations) is presented. Several transponder implementations supporting different transmission techniques are considered, highlighting advantages, economics, and complexity. Discussions include electronics, optical components, integration, and programmability. Application use cases are reported.

Next generation optical nodes: The vision of the European research project IDEALIST

As traffic demands become more uncertain and newer services continuously arise, novel network elements are needed to provide more flexibility, scalability, resilience and adaptability to todays optical networks. Considering these requirements, within the European project IDEALIST the investigation of elastic optical networks is undertaken with special focus on next generation optical node architectures. As an evolution of existent ROADMs and OXCs, these optical nodes will establish a new paradigm in which the network requirements will be efficiently addressed considering various emerging dimensions. In this article, we describe the drivers, architectures, and technologies that will enable these novel optical nodes. In addition, multivendor traffic interoperability, optical defragmentation, and node cascadability are also described as considerations in the node design.

Network architectures for CPRI backhauling

Mobile networks evolution is heavily driven by the increasing diffusion of broad-band wireless devices. The quickly growing traffic has to be managed by operators drastically reducing CAPEX and OPEX of their networks per transported bandwidth unit: in some cases this may imply the adoption of revolutionary, more than evolutionary approaches. Under this extent, an important case is CPRI backhauling: a new network paradigm implying centralization of mobile base-band units. The paper describes different functional and physical architectures for CPRI backhauling, comparing them under different CAPEX and OPEX impacting aspects.

Dynamic Differential Delay Aware RMSA for Elastic Multi-path Provisioning in GMPLS Flexi-grid DWDM Networks

We experimentally evaluate multi-path RMSA algorithms that minimize the differential delay and the required buffer capacity. A proof-of-concept of multi-path routing, provisioning and transmission with a GMPLS-controlled Flexi-grid DWDM setup using S-BVTs is also presented.

Real-time demonstration of software-defined Elastic interface for flexgrid networks

We demonstrate a real-time Elastic Interface for future flex-grid networks with a software-defined symbol rate transmission. Using PDM-QPSK modulation, live experiments show a line rate adaptation from 10.7 to 107Gbit/s with a sub-millisecond reconfiguration time.

Synchronization techniques in backhauling networks

Synchronization in transport networks was a hot topic for telecom in early 90s with the advent of SDH, replacing PDH. When packet networks and the Internet began to spread, it subsided for some years, until mobile technologies evolved from TDM (2G) to packets (3G, 4G). Nowadays the transport of frequency and time over transport networks is one of the most debated topics both in the industry and within international standard bodies, presenting several challenging aspects that even tend to multiply as new technologies not originally thought to carry synchronization are used for mobile backhauling, ranging from packets (L2 and L3), to TDM and WDM (OTN, CPRI). In this paper we analyse from a technical and economical point of view common problems and solutions related to the transport of frequency and time across several types of TDM and packet networks, summarizing latest research results, open issues and possible directions for evolution.

Extending the scope of OTN to access and metro networks

Network based on OTN standard (ITU-T G.709), originally devised for core networks, are foreseen to play an important role also in metro and possibly access optical networks, because of the always increasing bandwidth needs as well as of some new (at least numerically) requirements like latency and jitter control. In a historical timeframe in which the standardization activity is primarily focused on the extension of the hierarchy beyond 100 Gb/s, in this paper we quickly recap the basics of OTN, some more recent standard trends, and describe a couple of access and metro applications to which the technology can be easily adapted, both for evolving legacy services, which still exist, to new transmission platforms and for delivering new 5G oriented services.

Overview of Standardization for D-RoF

The main standard references for Digital Radio over Fiber (D-RoF) transmission are CPRI (Common Public Radio Interface) and OBSAI (Open Base Station Architecture Initiative). OBSAI has a wider extent than CPRI, since it describes not only the interface between the radio base station and the remote radio head, like CPRI, but also the base station system architecture. Nevertheless, CPRI is the technology mostly deployed, both for intra-site connectivity and for front-hauling, a recently developed network paradigm known also as C-RAN (Cloud Radio Access Network), which implies the physical separation of base stations from radio units and their centralization in a central office. This chapter provides the reader with a view on the objectives, the referenced architectures, and the state of the art of the regulations for each of these technologies, with a special attention given to the aspects and standardization activities relative to the possibility of transporting D-RoF over geographical distances, as it is implied by front-hauling. Finally, a brief reference is made to ORI (Open Radio Interface) activity, setup in 2010 by ETSI (European Telecommunications Standards Institute). ORI recognizes that actually neither CPRI nor OBSAI have been designed having in mind full compatibility between equipment from different vendors, and therefore aims at developing a really open D-RoF interface, mainly leveraging on CPRI existing specifications.