Arianna Rufini

QoE and QoS comparison in an anycast digital television platform operating on passive optical network

We report an experimental investigation on QoE, compared with the QoS, for a complete digital television platform able to deliver broadcast, multicast and unicast services in wide geographical area network, with broadband access based on passive optical network (PON). In particular, we show the service degradation due both to network impairments and to the TCP limits on operating systems. Multicast forwarding was tested in PBB-TE environment to exploit a Carrier Ethernet behavior. Concerning broadcasting, such a network allows the user to see the DVB-T by using the same optical infrastructure by means of the specific wavelength foreseen by the GPON standard.

Multilevel bandwidth measurements and capacity exploitation in gigabit passive optical networks

The authors report an experimental investigation on the measurement of the available bandwidth for the users in gigabit passive optical networks (GPON) and the limitations caused by the Internet protocols, and transfer control protocol (TCP) in particular. We point out that the huge capacity offered by the GPON highlights the enormous differences that can be showed among the available and actually exploitable bandwidth. In fact, while the physical layer capacity can reach value of 100 Mb/s and more, the bandwidth at disposal of the user (i.e. either throughput at transport layer or goodput at application layer) can be much lower when applications and services based on TCP protocol are considered. In the context of service level agreements (SLA) verification, we show how to simultaneously measure throughput and line capacity by offering a method to verify multilayer SLA. We also show how it is possible to better exploit the physical layer capacity by adopting multiple TCP connections avoiding the bottleneck of a single connection.

Experimental study on Protection Distances between LTE and DVB-T stations operating in adjacent UHF frequency bands

The present work aims to provide an effective contribution in the analysis of the coexistence problem between DVB-T signals, operating in the lower part of the UHF band (470–790 MHz), and signals of future mobile communication systems (LTE), operating in the digital dividend portion of the UHF spectrum (from 790 MHz to 862 MHz), resulting from the digital switchover process. Simulation analysis are carried out to estimate adjacent channel interfering effects of LTE Base Station (BS) and User Equipment (UE) signals on DVB-T receiver systems, through the computation of the correspondent Protection Distance in some specific operative scenarios. The goal of this analysis is to provide valuable inputs, in the mentioned frequency bands, in case of new mobile cellular networks deployment.

Femtocell technology combined to a condominium cabled infrastructure

Fixed-mobile convergence has the potentiality to break down some of the physical barriers that now prevent telecom service providers from reaching all of their potential customers with all types of services. The breakthrough combination of wireline backhaul with wireless technology seems to represent a concrete quantum leap in terms of spectrum utilization, capacity and quality of service as well as it allows costs reduction and service differentiation.

An integrated access network infrastructure combining femtocells to existing cabled networks

Wireless technology is a fast, flexible and easy-to-deploy solution to provide broadband access. In this context, the adoption of Femtocell Access Points, operating in the licensed cellular bands and typically designed to be used in SOHO, will improve the radio coverage and the building penetration of the existing mobile networks, based on macrocells. In the present paper an innovative approach to access the end user, relying on infrastructural integration of femtocellular technology with existing cabled networks, is proposed. This peculiar solution is further strengthened by the growing interest towards the possible deployment of mobile technologies in both the last portion of the UHF band V and the GSM frequency band, resulting from the re-farming process.

Experimental and simulation investigation on the TCP performance for wireless broadband environment

Next Generation Networks provide opportunities and challenges for data communication. In particular, the ever increasing bandwidth poses a major challenge to transport layer protocols such as TCP. In this paper the performance of TCP in large bandwidth delay networks, with particular regard to wireless network scenarios, is experimentally investigated. In particular we apply an accredited standard technique for end-user bandwidth evaluation in wireless access environments showing limitations in the bandwidth exploitation. This investigation shows how end-to-end bandwidth measurements depend strongly on the TCP implementation in a broadband access network. We also simulated the experimental environment by means of ns-3 code, reproducing the same experimental results. This simulation approach allows us to foresee scenarios that cannot be analyzed in laboratories and to investigate future 5G infrastructures.

A Femtocellular-Cabled Solution for Broadband Wireless Access: A Qualitative and Comparative Analysis

Broadband Wireless Access is a strategic opportunity for mobile operators which aim to provide connectivity in digital divide areas, in order to accelerate speed of deployment and save in installation costs. This paper presents an innovative approach to access the end user, relying on infrastructural integration of femtocellular technology with existing cabled network. Usually, the adoption of Femtocell Access Points, operating in the licensed cellular bands typically designed to be used in SOHO, improves the radio coverage and the building penetration of the existing mobile networks, based on macrocells. In the proposed solution, the peculiar functionality of femtocells is further improved using a MATV/SMATV cabled infrastructure which facilitates the signal connection inside the building. The potentiality of the solution is even more evident, taking into account the growing interest towards the possible deployment of new mobile technologies, like LTE in both the last portion of the UHF band V and the GSM frequency band, resulting from the re-farming process.

Ultra broadband access network performance in a multi operator scenario

The Digital Agenda for Europe (DAE) mandates that 100-Mbit/s Internet access should be available to 50% of the households. Fiber to the Cabinet and Fiber to the Building are appealing architectures to quickly achieve this goal. This paper compares the standard copper technologies G.fast, VDSL2 and their enhancements in a multi-operator environment. The paper shows that both G.fast and the new EVDSL technology can meet the DAE goals.

Quality of Service monitoring adopting correlation among active and passive measurements: The experience from the FP7 mPlane project

In this work we report the final results of the field demonstration of the European FP7 mPlane project concerning the evaluation of the network performance with particular details regarding the access Quality of Service and traffic monitoring. We show how the proposed and experimented architecture of this measurement plane is fundamental for many future internet evolutions concerning user perception, content popularity web quality and network management. Here we point out the results dedicated to service level agreement verification and certification with analysis of the correlation between passive and active measurements in order to understand some causes concerning network and service anomalies.

Evaluation of the hybrid FTTx/VDSL2-Vectoring approach in an access network

Fibre to the Home (FTTH) is currently the best solution to meet the requirements of the Digital Europe Agenda within the Europe 2020 strategy, concerning with the increase of the high speed access usage among the European citizens. Nevertheless, the roll-out of FTTH has high costs for the deployment of the optical fibres and the equipment that limit the investments from the operators. Therefore, the recent hybrid technologies that exploit the current copper-based access for the secondary network, with loop length of 300 m, combined to the Fibre to the Cabinet (FTTC) approach for the primary network, represents a valid alternative from the technical and economical points of view, meeting the requirement of high bandwidth availability for the user. An example of such technologies is the Vectoring technique applied to the VDSL2 access, that allows for connection speeds up to 100 Mbps on loop length of 300 m, whose actual performance depends on the conditions of the cables and the individual pairs. This work will show the results of the characterization of the FEXT (Far End Cross Talk) penalties in FTTC and FTTB access networks achieved by means of a physical cable simulator. In particular, the impact of the use of the Vectoring technique applied to VDSL2 technology in a multi operator scenario will be assessed.