Marco Miozzo

An open source product-oriented LTE network simulator based on ns-3

In this paper we present a new simulation module for ns-3 aimed at the simulation of LTE networks. This module has been designed with a product-oriented perspective in order to allow LTE equipment manufacturers to test RRM/SON algorithms in a simulation environment before they are deployed in the field. First, we describe the design of our simulation module, highlighting its novel aspects. Subsequently, we discuss the testing methodology that we adopted to validate its output. Finally, we present some experimental result to assess its performance in terms of execution time and memory usage.

Miracle: the multi-interface cross-layer extension of ns2

We present Miracle, a novel framework which extends ns2 to facilitate the simulation and the design of beyond 4G networks. Miracle enhances ns2 by providing an efficient and embedded engine for handling cross-layer messages and, at the same time, enabling the coexistence of multiple modules within each layer of the protocol stack. We also present a novel framework developed as an extension of Miracle called Miracle PHY and MAC. This framework facilitates the development of more realistic Channel, PHY and MAC modules, considering features currently lacking in most state-of-the-art simulators, while at the same time giving a strong emphasis on code modularity, interoperability and reusability. Finally, we provide an overview of the wireless technologies implemented in Miracle, discussing in particular the models for the IEEE 802.11, UMTS and WiMAX standards and for Underwater Acoustic Networks. We observe that, thanks to Miracle and its extensions, it is possible to carefully simulate complex network architectures at all the OSI layers, from the physical reception model to standard applications and system management schemes. This allows to have a comprehensive view of all the interactions among network components, which play an important role in many research areas, such as cognitive networking and cross-layer design.

A Model to Analyze the Energy Savings of Base Station Sleep Mode in LTE HetNets

In this paper we study the base station (BS) sleep mode as an approach to decrease the energy consumption of LTE HetNets. We present an energy model which takes into account that (i) macro, micro and pico BSs have different power consumption profiles, (ii) macro BS power consumption is varying with the load, and (iii) communication through a macro, micro or pico cell has different radio resource utilization. Furthermore, we introduce two sleep algorithms, namely single sleep and multiple sleep, to determine the time instant to enable micro or pico BSs sleep mode. Finally, we analyze the two proposed algorithms in different HetNet topologies and with different traffic requirements to evaluate the network energy consumption and the savings that the sleep mode can achieve.

Spectrum-aware channel and PHY layer modeling for ns3

The recent interest in tackling the frequency-dependent aspects of communications is pushing a demand for spectrum awareness in simulation tools. Unfortunately, most current network simulators do not deal with this aspect in a satisfactory fashion. In this paper, we present a framework that we developed for the ns3 simulator with the aim of addressing this issue. We discuss the modeling assumptions on which our design is based, and we describe in detail the implementation of the framework as well as of the PHY layer modules that we developed on top of it. Finally, we report some performance evaluation results which show that the proposed solution can achieve a good spectrum modeling accuracy with a modest increase in the computational load.

A lightweight and accurate link abstraction model for the simulation of LTE networks in ns-3

In this work we present a link abstraction model for the simulation of downlink data transmission in LTE networks. The purpose of this model is to provide an accurate link performance metric at a low computational cost by relying solely on the knowledge of the SINR and of the modulation and coding scheme. To this aim, the model combines Mutual Information-based multi-carrier compression metrics with Link-Level performance curves matching, to obtain lookup tables that express the dependency of the Block Error Rate on the SINR values and on the modulation and coding scheme being used. In addition, we propose a 3GPP-compliant Channel Quality Indicator evaluation procedure, based on the proposed Link Abstraction Model, to be used as part of the LTE Adaptive Modulation and Coding mechanisms. Finally, we discuss how these contributions have been tested, validated and integrated in the ns-3 simulator. The link abstraction model described in this paper has been included in the official ns-3 distribution since release 3.14.

Routing schemes in heterogeneous wireless networks based on access advertisement and backward utilities for QoS support [Quality of Service based Routing Algorithms for Heterogeneous Networks]

This article reviews routing algorithms in heterogeneous wireless networks with the goal of including QoS awareness. After a general overview of the issues and challenges of QoS provisioning over heterogeneous networks, classic routing strategies are revisited, and how they can be exploited to achieve QoS efficiency is discussed. In particular, for the considered scenarios our proposal is to account for some proactivity in the routing algorithms, as well as a QoS-driven control selection, which are shown to improve throughput, delay, and energy consumption. Finally, we introduce a general backward utility formulation for user satisfaction as a tool to capture complex and dynamic QoS variations

SolarStat: Modeling photovoltaic sources through stochastic Markov processes

In this paper, we present a methodology and a tool to derive simple and accurate stochastic Markov processes for the description of the energy scavenged by outdoor solar sources. In particular, we target photovoltaic panels with small form factors, as those exploited by embedded communication devices such as wireless sensor nodes or, concerning modern cellular system technology, by small-cells. Our models are especially useful for the theoretical investigation and the simulation of energetically self-sufficient communication systems that include these devices.The Markov models that we derive in this paper are obtained from extensive solar radiation databases, that are widely available online. Basically, from hourly radiance patterns, we derive the corresponding amount of energy (current and voltage) that is accumulated over time, and we finally use it to represent the scavenged energy in terms of its relevant statistics. Toward this end, two clustering approaches for the raw radiance data are described and the resulting Markov models are compared against the empirical distributions. Our results indicate that Markov models with just two states provide a rough characterization of the real data traces. While these could be sufficiently accurate for certain applications, slightly increasing the number of states to, e.g., eight, allows the representation of the real energy inflow process with an excellent level of accuracy in terms of first and second order statistics. Our tool has been developed using Matlab™ and is available under the GPL license at [1].

A new approach to simulating PHY, MAC and routing

In recent years, network simulation has become a very difficult task due to the proliferation and integration of wireless technologies. In this paper, we discuss the new challenges that have arisen regarding the simulation of the wireless channel and the PHY, MAC and Routing layers, argumenting why currently available network simulation tools such as ns2 and many of its recently proposed extensions do not address all these issues in a comprehensive and systematic fashion. We then present a novel framework designed to address these challenges. This framework has been developed as an extension of NS-Miracle, in order to have support in the definition and management of scenarios involving the use of multiple interfaces and radio technologies, and is made up of two components. The first component is the Miracle PHY and MAC framework, which provides support for the development of Channel, PHY and MAC modules, providing support for features currently lacking in most state-of-the-art simulators, while at the same time giving a strong emphasis on code modularity, interoperability and reusability. The second component is the Miracle Routing framework, which enables the integration of different routing schemes in a multi-tier architecture to provide support for the simulation of multi-technology and heterogeneous networks. We want to observe that, thanks to this framework, it is now possible to carefully simulate complex network architectures potentially at all the OSI layers, from the physical reception model to standard applications and system management schemes. This allows to have both a comprehensive view of all the networks interactions and its high level view, which plays an important role in many research investigation area, such as cognitive networking and cross-layer design.

On the exploitation of user aggregation strategies in heterogeneous wireless networks

In this paper we discuss the exploitation of aggregated mobility patterns and physical proximity of nodes in a so-called ambient network, i.e., a wireless network with heterogeneous nodes and access techniques. We advocate to use the knowledge about node movements and geographical positions to create routing groups of adjacent nodes, which might be beneficial in order to decrease signaling overhead and increase transmission efficiency. Basically, routing groups (RGs) consist of aggregated logical structures which are built and maintained at the application layer. Their aim is to decrease the signaling overhead between group of nodes and access points and, at the same time, to improve connectivity by exploiting technology diversity and relaying techniques. On this matter, we describe a validation through simulation of a previously developed analytical work which is useful to evaluate the effectiveness of RG structures. Finally, we show the validity of the RG approach in terms of throughput and connectivity performance

When telecommunications networks meet energy grids: cellular networks with energy harvesting and trading capabilities

In this article, we cover eco-friendly cellular networks, discussing the benefits that ambient energy harvesting offers in terms of energy consumption and profit. We advocate for future networks where energy harvesting will be massively employed to power network elements; even further, communication networks will seamlessly blend with future power grids. This vision entails the fact that future base stations may trade some of the excess energy they harvest so as to make a profit and provide ancillary services to the electricity grid. We start by discussing recent developments in the energy harvesting field, and then deliberate on the way future energy markets are expected to evolve and the new fundamental trade-offs that arise when energy can be traded. Performance estimates are given throughout to support our arguments, and open research issues in this emerging field are discussed.