Diomidis S. Michalopoulos

Network Slicing to Enable Scalability and Flexibility in 5G Mobile Networks

We argue for network slicing as an efficient solution that addresses the diverse requirements of 5G mobile networks, thus providing the necessary flexibility and scalability associated with future network implementations. We elaborate on the challenges that emerge when designing 5G networks based on network slicing. We focus on the architectural aspects associated with the coexistence of dedicated as well as shared slices in the network. In particular, we analyze the realization options of a flexible radio access network with focus on network slicing and their impact on the design of 5G mobile networks. In addition to the technical study, this article provides an investigation of the revenue potential of network slicing, where the applications that originate from this concept and the profit capabilities from the network operator�s perspective are put forward.

User-plane multi-connectivity aspects in 5G

We present an overview of the concept of multi-connectivity, as seen from the user-plane perspective of 5G mobile networks. The potential of multi-connectivity is discussed, when utilized towards higher throughput and/or higher reliability in 5G. Two major architecture options are considered, namely the traditional X2-based approach, and an architecture with centralized packet data convergence protocol (PDCP) layer, which are associated with different network deployments. An assessment of multi-connectivity over its intra-site counterpart, carrier aggregation, is presented, in terms of performance potential as well as in terms of the technical challenges involved.

Multi-connectivity functional architectures in 5G

Future mobile networks need to fulfill stringent requirements on data rates, reliability, and availability. In order to satisfy these requirements, heterogeneous radio access technologies and deployments need to be used. To make efficient use of these technologies, multi-connectivity has been proposed to connect to multiple different technologies simultaneously. In this paper, we discuss different options to connect to multiple radio access points. Each of these options is further detailed, novel functionality required for multi-connectivity is introduced, and expected benefits are explained.

Performance Analysis of Near-Optimal Energy Buffer Aided Wireless Powered Communication

In this paper, we consider a wireless powered communication system, where an energy harvesting (EH) node harvests energy from a radio frequency (RF) signal broadcasted by an access point (AP) in the downlink (DL). The node stores the harvested energy in an energy buffer and uses the stored energy to transmit data to the AP in the uplink (UL). We investigate two simple online transmission policies for the EH node, namely a best-effort policy and an on-off policy, which do not require knowledge of the EH profile nor channel knowledge. In particular, for both policies, the EH node transmits in each time slot with a constant desired power if sufficient energy is available in its energy buffer. Otherwise, the node transmits with the maximum possible power in the best-effort policy and remains silent in the on-off policy. For both policies, we use the theory of discrete-time continuous-state Markov chains to analyze the limiting distribution of the stored energy for finite- and infinite-size energy buffers. We provide this limiting distribution in closed form for a Nakagami-

An improved method for on-demand system information broadcast in 5G networks

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Network Resilience in Virtualized Architectures

fading DL channel and analyze the outage probability for a Nakagami-

Multi-user Scheduling Schemes for Simultaneous Wireless Information and Power Transfer Over Heterogeneous Fading Channels.

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Network slicing via function decomposition and flexible network design

fading UL channel. All derived analytical results are not limited to EH via RF WPT but are applicable for any independent and identically distributed EH process from e.g. solar and wind energy. Our results reveal that, for low-to-medium outage probabilities, the best-effort policy is superior to the on-off policy and the optimal UL transmit power of the EH node that minimizes the outage probability is always less than the average harvested power. The opposite behaviour is observed for high outage probabilities. Furthermore, we show that the minimum outage probability of the two proposed policies is near-optimal.

PROCÉDÉ ET APPAREIL POUR RÉALISER UNE DUPLICATION DE PAQUETS DANS UN SCÉNARIO À CONNECTIVITÉ MULTIPLE

We argue for a new method that applies to on-demand system information (SI) broadcast transmissions. The proposed method is targeted for 5G networks, and is based upon utilizing a cut-off value for the modulation and coding scheme used for broadcasting. Two variants of the proposed scheme are presented, namely the reactive and proactive method, depending on whether the user equipment requests an additional (re)-transmission of the SI message before or after the reception of the first transmission. The main advantage of this approach is an increase of the resource usage efficiency, which is evaluated through closed-form expressions. The mathematical analysis is complemented by an extensive set of numerical results, which are corroborated via simulations.

Handover with postponed path switch

Network resilience represents one of the major requirements of next generation networks. It refers to an increased level of availability, which is of high importance especially for certain critical services. In this work, we argue for resilience as an intrinsic feature that spans multiple network domains, thereby providing a network-wide failsafe operation. Particular focus is put on virtualized architectures envisioned for 5G and beyond. Contrary to traditional architectures where all network functions were hardware-dependent, a virtualized architecture allows a portion of such functions to run in virtualized environment, i.e., in a telco cloud, allowing thus for a wider deployment flexibility. Nonetheless, parts of this architecture such as radio access might still have strong hardware dependency due to, for instance, performance requirements of the physical nature of the network elements. Capitalizing on this architecture, we shed light onto the techniques designed to guarantee resilience at the radio access as well as the telco cloud network domains. Moreover, we highlight the ability of the envisioned architecture to address security-related issues by applying threat monitoring and prevention mechanisms, along with proper reaction approaches that isolate security intrusions to limited zones.