Eirini Liotou

National Technical University of Athens | NTUA · Institute of Communication and Computer Systems (ICCS)

It is expected that the communication fabric and the way network services are consumed will evolve towards 6G, building on and extending capabilities of 5G and Beyond networks. Service APIs, Operation APIs, Network APIs are different aspects of the network exposure, which provides the communication service providers a way to monetize the network ca...

Dynamic Adaptive Streaming over HTTP (DASH) has prevailed as the dominant way of video transmission over the Internet. This technology is based on receiving small sequential video segments from a server. However, one challenge that has not been adequately examined is the obtainment of video segments in a way that serves both the needs of the networ...

The fifth generation of mobile networks (5G) is rapidly reaching deployment across the globe, promising a series of advances for vertical service providers, both in terms of performance and in terms of operational capabilities. In this context, the 5G-IANA Network Application platform focuses on the rapidly advancing domain of intelligent, data cen...

The advent of 5G has been a game-changer in the Automotive Vertical sector. 5G acts as an enabler of advanced networking architectures which, in turn, allow the development of novel services, by attracting and engaging third parties to experiment using available 5G infrastructure and connectivity. 5G-IANA is a Horizon 2020 ICT-41 project that targe...

With the coming of age of virtual/augmented reality and interactive media, numerous definitions, frameworks, and models of immersion have emerged across different fields ranging from computer graphics to literary works. Immersion is oftentimes used interchangeably with presence as both concepts are closely related. However, there are noticeable int...

This paper presents an overview of the project CASPER¹, a 4-year Marie Curie Research and Innovation Staff Exchange (RISE) project running between 2016-2020, describing its objectives, approach, architecture, tools and key achievements. CASPER combines academic and industrial forces towards leveraging the expected benefits of Quality of Experience...

With the coming of age of virtual/augmented reality and interactive media, numerous definitions, frameworks, and models of immersion have emerged across different fields ranging from computer graphics to literary works. Immersion is oftentimes used interchangeably with presence as both concepts are closely related. However, there are noticeable int...

This paper presents an overview of the project CASPER , a Marie Curie Research and Innovation Staff Exchange (RISE) project running from 2016 until 2020. The main objective of CASPER is to combine academic and industrial forces towards leveraging the expected benefits of Quality of Experience (QoE) exploitation in future digital networks. In partic...

Traditionally, previous generations of mobile cellular networks have been designed with Quality of Service (QoS) criteria in mind, so that they manage to meet specific service requirements. Quality of Experience (QoE) has, however, recently emerged as a concept, disrupting the design of future network generations by giving clear emphasis on the act...

Video streaming has become an indispensable technology in people's lives, while its usage keeps constantly increasing. The variability, instability and unpredictability of network conditions poses one of the biggest challenges to video streaming. In this chapter, we analyze HTTP Adaptive Streaming, a technology that relieves these issues by adaptin...

This chapter discusses prospects of QoE management for future networks and applications. After motivating QoE management, it first provides an introduction to the concept by discussing its origins, key terms and giving an overview of the most relevant existing theoretical frameworks. Then, recent research on promising technical approaches to QoE-dr...

Studies that address Quality of Experience (QoE) management of multimedia systems and services are faced with the challenge of identifying the key QoE influence factors to be considered. Still, some consensus on the role of system factors, human factors, and context factors for various applications domains exists in these studies. In this paper, we...

While video streaming has dominated the Internet traffic, Video Service Providers (VSPs) compete on how to assure the best Quality of Experience (QoE) to their customers. HTTP Adaptive Streaming (HAS) has become the de facto way that helps VSPs work-around potential network bottlenecks that inevitably cause stallings. However, HAS-alone cannot guar...

This paper presents the design of the CASPER middleware architecture that enables the implementation of real-time QoE-driven service management. More in detail, we thoroughly describe the new modules, methods and functionalities that need to be integrated into the network providers’ infrastructure, according to CASPER. Based on this architecture, f...

Video streaming has become an indispensable technology in people’s lives. However, the variability and instability of network conditions poses one of the biggest challenges to video streaming. In this paper, we study HTTP Adaptive Streaming (HAS), a technology that relieves these issues by adapting the video reproduction to the current network cond...

As we are moving forward to the 5G era, we are witnessing a transformation in the way networks are designed and behave, with the end-user placed at the epicenter of any decision. One of the most promising contributors towards this direction is the shift from Quality of Service (QoS) to Quality of Experience (QoE) service provisioning paradigms. QoE...

Radio scheduling is a well-studied problem that has challenged researchers throughout the last decades. However, recent findings that stem from the Quality of Experience (QoE) domain come to give a new perspective to traditional radio scheduling approaches. In this paper, we take advantage of recent subjective results regarding the impact of throug...

The rise in popularity of TCP-based video streaming in recent years is unbroken. These streaming services not just operate on wired access lines but more and more specifically target users of mobile networks as well. Yet it still remains difficult to evaluate the performance of such streaming approaches in mobile networks. This is especially critic...

Quality of Experience (QoE) is a research area that has attracted genuine interest in the last few years. Particularly for mobile network operators, QoE awareness seems to be the most appealing way to better understand the quality that their customers perceive, and, thereafter, to improve their experience. This extended abstract is focusing on the...

5G communications are expected to adopt a user-centric service provisioning approach, transforming the current Quality of Service (QoS) networking paradigm to a Quality of Experience (QoE) platform. Towards this direction, the design of QoE quantification methods is a vast necessity, prior to the design of QoE-driven service/network management tech...

Video quality measurement is an important component in the end-to-end video delivery chain. Video quality is, however, subjective and thus there will always be inter-observer differences in the subjective opinion about the visual quality of the same video. Despite this, most existing works on objective quality measurement typically focus only on pr...

Currently, cellular networks are evolving towards providing high quality mobile services in a ubiquitous manner. In this direction, increased robustness is required to face fluctuations at the service quality that follow traffic demanding events, such as an earthquake or a blackout. Dealing with this challenge, we propose a cross-layer scheme, whic...

Telecom operators have recently faced the need for a radical shift from technical quality requirements to customer experience guarantees. This trend has emerged due to the constantly increasing amount of mobile devices and applications and the explosion of overall traffic demand, forming a new era: "the rise of the consumer". New terms have been co...

5G is rapidly moving from vision to reality and there is already some consensus regarding the technical requirements of 5G. Traditionally, performance monitoring based on existing standards has been focusing on technical Key Performance Indicators (KPIs). However, it is actually more important to focus on Quality of Experience (QoE) directly. Servi...

This paper provides a brief overview and a vision for introducing a Quality of Experience (QoE) function for on-demand services or for premium users, based-on Software-Defined Networking (SDN). The proposed “QoE-service” can take advantage of the SDN global resource view and complementary QoE metrics to assure the desired performance for OTT applic...

Device-to-Device (D2D) communication has been recently devised as a new paradigm that boosts spectrum reuse inside a cell, leading to enhanced quality of service and user experience. The design of proper D2D resource allocation schemes, which constitute the enablers towards this direction, is an open challenge. In this paper, we propose a D2D resou...

Device-to-Device (D2D) communications are planned to become an indispensable part of future mobile networks. A lot of attention has been paid to this new communication paradigm, due to the important benefits it brings for both cellular operators and end-users. Standardization efforts towards enabling D2D connections have started in Release 12 of th...

Considering the benefits arisen due to the proximity gain and the plethora of potential applications in modern mobile cellular networks, device-to-device (D2D) communications have currently drawn the interest of academia and standardization bodies. This chapter focuses on the Long Term Evolution--Advanced (LTE-A) system, and deals with open challen...

Device-to-Device (D2D) communications provide the means to users of cellular networks for spatially reusing licensed spectrum by establishing direct connections. Considering the benefits for operators and consumers, a plethora of resource and interference management approaches in the literature deal with parallel cellular and D2D transmissions. How...

Under the current requirements for mobile, ubiquitous and highly reliable communications, internet and mobile communication technologies have converged to an all-Internet Protocol (IP) packet network. This technological evolution is followed by a major change in the cellular networks’ architecture, where the traditional wide-range cells (macrocells...

The Long Term Evolution (LTE) system, and especially its current release, LTE-Advanced, is considered as the next step in mobile broadband networks. Two of the main challenges faced by the LTE system are: i) to offer ubiquitous and highly reliable wireless services, and ii) to efficiently utilize the assigned spec- trum portion. A promising approac...