Eirini Liotou

Dr. Eirini Liotou

Department of Informatics and Telecommunications, National and Kapodistrian University of Athens, Athens, Greece

Research Focus & Metrics

Academic Career Length

13Years (2014-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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15 March 2018 in IEEE Journal on Selected Areas in Communications
Verified
Journal Article
Open access
ELEirini Liotou
Eirini Liotou
KSKonstantinos Samdanis
Konstantinos Samdanis
EPEmmanouil Pateromichelakis
Emmanouil Pateromichelakis
NPNikos Passas
Nikos Passas
LMLazaros Merakos
Lazaros Merakos
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 guarantee a seamless viewing experience, since this highly relies on the mobile network operators' (MNOs) infrastructure and evolving network conditions. Software-defined networking (SDN) has brought new perspectives to this traditional paradigm where VSPs and MNOs are isolated, allowing the latter to open their network for more flexible, service-oriented programmability. This paper takes advantage of recent standardization trends in SDN and proposes a programmable QoE-SDN App, enabling network exposure feedback from MNOs to VSPs towards network-aware video segment selection and caching, in the context of HAS. The video selection problem is formulated using Knapsack optimization and relaxed to partial sub-problems that provide segment encodings that can mitigate stallings. Furthermore, a mobility prediction mechanism based on the Self-similar Least-Action Walk model is introduced, toward proactive segment caching. A number of use cases, enabled by the QoE-SDN App, are designed to evaluate the proposed scheme, revealing QoE benefits for VSPs and bandwidth savings for MNOs.

6 April 2014
Verified
Book Chapter
Closed access
PDF file
DTDimitris Tsolkas
Dimitris Tsolkas
ELEirini Liotou
Eirini Liotou
NPNikos Passas
Nikos Passas
LMLazaros Merakos
Lazaros Merakos

24 March 2026 in IEEE Open Journal of the Communications Society
Verified
Journal Article
Open access
CCConstantina Chatzieleftheriou
Constantina Chatzieleftheriou
ELEirini Liotou
Eirini Liotou
As wireless communication evolves, each generation of networks brings new technologies that change how we connect and interact. Artificial Intelligence (AI) is becoming crucial in shaping the future of sixth-generation (6G) networks. By combining AI and Machine Learning (ML), 6G aims to offer high data rates, low latency, and extensive connectivity for applications including smart cities, autonomous systems, holographic telepresence, and the tactile internet. This paper provides a detailed overview of the role of AI in supporting 6G networks. It focuses on key technologies like deep learning, reinforcement learning, federated learning, and explainable AI. It also looks at how AI integrates with essential network functions and discusses challenges related to scalability, security, and energy efficiency, along with new solutions. Additionally, this work highlights perspectives that connect AI-driven analytics to 6G service domains like Ultra-Reliable Low-Latency Communication (URLLC), Enhanced Mobile Broadband (eMBB), Massive Machine-Type Communication (mMTC), and Integrated Sensing and Communication (ISAC). It addresses concerns about standardization, ethics, and sustainability. By summarizing recent research trends and identifying future directions, this survey offers a valuable reference for researchers and practitioners at the intersection of AI and next-generation wireless communication.

1 November 2016 in Computer Networks
Verified
Journal Article
Closed access
FMFlorian Metzger
Florian Metzger
ELEirini Liotou
Eirini Liotou
CMChristian Moldovan
Christian Moldovan
THTobias Hoßfeld
Tobias Hoßfeld

1 May 2016
Verified
Conference Paper
Closed access
ELEirini Liotou
Eirini Liotou
Tobias HossfeldTobias Hossfeld
Tobias Hossfeld
CMChristian Moldovan
Christian Moldovan
FMFlorian Metzger
Florian Metzger
DTDimitris Tsolkas
Dimitris Tsolkas
NPNikos Passas
Nikos Passas
Video streaming provided by Over-The-Top (OTT) service providers through a cellular network is a common usage scenario for many people today. While video streaming will work reasonably well in a stationary scenario, several issues arise for mobile users. For instance, travelling through short areas without cellular coverage, such as an automobile tunnel, will often result in quality degradation or video stalling. To combat this, this paper provides an analytical investigation of the video quality degradation problem as it is experienced by mobile users and suggests a context-aware HTTP Adaptive Streaming (HAS) strategy to prevent stalling and minimize the impact on Quality of Experience (QoE). This provides a solution that can completely prevent stalling when appropriate context information (such as positional information from satellite navigation) is present. The collected evaluation results encourage further research on how context-awareness can be exploited to further enhance video service provisioning by OTT service providers.

21 June 2023 in Future Internet
Verified
Journal Article
Open access
PDF file
ELEirini Liotou
Eirini Liotou
DXDionysis Xenakis
Dionysis Xenakis
VGVasiliki Georgara
Vasiliki Georgara
GKGeorgios Kourouniotis
Georgios Kourouniotis
LMLazaros Merakos
Lazaros Merakos
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 network and the improvement in the Quality of Experience (QoE) of the users. One effective way to achieve this is to implement and study caching and DASH technologies together. This paper investigates this issue by simulating a network with multiple video servers and a video client. It then implements both the peer-to-many communications in the context of adaptive video streaming and the video server caching algorithm based on proposed criteria that improve the status of the network and/or the user. Specifically, we investigate the scenario of delivering DASH-based content with the help of an intermediate server, apart from a main server, to demonstrate possible caching benefits for different sizes of intermediate storage servers. Extensive experimentation using emulation reveals the interplay and delicate balance between caching and DASH, guiding such network design decisions. A general tendency found is that, as the available buffer size increases, the video playback quality increases to some extent. However, at the same time, this improvement is linked to the random cache selection algorithm.