Publications

MATCH: Multiple Access for multiple Traffic Classes in 5G HetNets

Authors: Virgilios Passas, Nikos Makris, Vasileios Miliotis, Thanasis Korakis and Leandros Tassiulas

Conference: IEEE International Conference on Communications (ICC), Kansas City, MO, USA, 20-24 May 2018

Abstract: Ultra-Dense Heterogeneous Network deployments are expected to boost the offered network capacity and enhance the user-perceived Quality of Experience, through the simultaneous offering of multiple technologies using distinct or shared wireless spectrum. In such environments with a plethora of available Radio Access Technologies (RATs), the network UEs shall decide either independently or assisted through operator based services on which network they shall use to better serve their needs. In this work, we model the network selection problem in a Multi-RAT system, based on the Paris Metro Pricing (PMP) scheme, enhanced with dynamic pricing formed by the congestion of each available technology. We assume that the network UEs are equipped with multi-homing features and thus are able to use concurrently more than one technologies, based on the requirements of the applications requesting network connectivity (e.g. UHD video streaming). We port and experimentally evaluate the proposed system model over a testbed setup, using distributed components running at the UEs and at a Core Network controller. We provide evaluation results on the average cost per UE for the selected RATs, the average data rate distribution of each UE per RAT and how these performance metrics are affected under different client ordering policies at the network controller.

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Employing MEC in the Cloud-RAN: An Experimental Analysis

Authors: Nikos Makris, Virgilios Passas, Thanasis Korakis and Leandros Tassiulas

Conference: ACM 2018 Technologies for the Wireless Edge Workshop (EdgeTech'18), November 2, 2018, New Delhi, India

Abstract: 5G network access is expected to deliver high performance with low-latency network connections for the end-users, suitable for a plethora of different applications, as well as add up to the network flexibility and manageability from the operator's perspective. In order to achieve low-latency, Multiple-access Edge Computing (MEC) is considered, whereas for achieving flexibility, the disaggregation of the base station elements and moving parts of their functionality to the Cloud is proposed. In this paper, we consider the case of disaggregated base stations based on the CU-DU paradigm, able to provision MEC functions in a per-packet and per-client basis, over real networks. We evaluate the placement of the MEC functions over the fronthaul interface or collocating them with the Core Network. We employ the OpenAirInterface platform and evaluate our MEC solution with dynamically adaptive video streams. Our results show significant gains for the service-to-UE path latency, complying with the requirements set for the 5G MEC operation.

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Integrating NFV-MANO with Wireless Services: Experiences and Testbed Development

Authors: Nikos Makris, Christos Zarafetas, Alexandros Valantasis, Thanasis Korakis and Leandros Tassiulas

Conference: Fourth IEEE International Workshop on Orchestration for Software Defined Infrastructures, in conjunction with the 4th IEEE Conference on Network Function Virtualization and Software Defined Networks (NFV-SDN 2018), Nov. 27 2018, Verona, Italy

Abstract: Network Functions Virtualization Management and Orchestration (NFV-MANO) aims to provide a common interface for technology developers and service operators for the instantiation of virtual network functions over generic equipment. Nevertheless, although NFV-MANO is currently targeting datacenter operations and the deployment of virtual services (through Virtual Machines or containers), it can easily extend to generic networking devices, and alter their operation based on the deployed network functions. In this paper, we consider the case of a wireless testbed, with focus on wireless networking, and adopt the OpenSourceMANO framework for provisioning of services on top of the equipment. We provide the necessary extensions to the framework in order to deploy services over virtualized wireless network interfaces, hosted on the generic networking nodes of the testbed. The extensions we focus on regard the provisioning of virtual functions over wireless links, that are traditionally not handled by the framework, and allow easier interaction of the end-users with the testbed.

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Fast Spectral Assessment for Handover Decisions in 5G Networks

Authors: K. Chounos, S. Keranidis, A. Apostolaras and T. Korakis

Conference: IEEE CCNC 2019, Las Vegas, NV, USA, 11 - 14 Jan 2019

Abstract: In this paper, we present a UE-driven light-weight mechanism for fast handover decision and efficient WLAN selection in the context of 5G networks. As the network deployments are expected to be denser and the mobile user will be offered a multitude of alternative short coverage range options to have her mobile traffic served, her roaming decision will be performance critical. While the current 3GPP standardization considers the use of network performance statistics of nearby WLANs for the UE-driven roaming selection to address the uncertainty of the shared wireless medium, their collection and processing inevitably affects the mobile user performance and inserts an accuracy-performance tradeoff. We introduce a spectrum assessment framework, that is based on commercial hardware and open-source software, to evaluate the conditions on the nearby WLANs and let the UE to infer their performance with minimum overhead relying on Duty Cycle evaluation and the RSSI metrics. Our ready-to-be deployed solution leverages the use of off-the-shelf equipment and commercial devices and enables fast decision procedures for the WLAN selection with low collection and processing overhead. We evaluate our mechanism by conducting testbed experiments. The results reveal performance gains in terms of UE's achieved throughput when enabling the proposed framework to infer the spectral WLAN conditions and decide for the AP to roam.