End-to-End Simulation of 5G mmWave Networks

Due to its potential for multi-gigabit and low latency wireless links, millimeter wave (mmWave) technology is expected to play a central role in 5th generation cellular systems. While there has been considerable progress in understanding the mmWave physical layer, innovations will be required at all layers of the protocol stack, in both the access and the core network. Discrete-event network simulation is essential for end-to-end, cross-layer research and development. This paper provides a tutorial on a recently developed full-stack mmWave module integrated into the widely used open-source ns--3 simulator. The module includes a number of detailed statistical channel models as well as the ability to incorporate real measurements or ray-tracing data. The Physical (PHY) and Medium Access Control (MAC) layers are modular and highly customizable, making it easy to integrate algorithms or compare Orthogonal Frequency Division Multiplexing (OFDM) numerologies, for example. The module is interfaced with the core network of the ns--3 Long Term Evolution (LTE) module for full-stack simulations of end-to-end connectivity, and advanced architectural features, such as dual-connectivity, are also available. To facilitate the understanding of the module, and verify its correct functioning, we provide several examples that show the performance of the custom mmWave stack as well as custom congestion control algorithms designed specifically for efficient utilization of the mmWave channel.Comment: 25 pages, 16 figures, submitted to IEEE Communications Surveys and Tutorials (revised Jan. 2018

Characterization, Avoidance and Repair of Packet Collisions in Inter-Vehicle Communication Networks

This work proposes a combined and accurate simulation of wireless channel, physical layer and networking aspects in order to bridge the gaps between the corresponding research communities. The resulting high fidelity simulations enable performance optimizations across multiple layers, and are used in the second part of this thesis to evaluate the impact of fast-fading channel characteristics on Carrier-Sense Multiple Access, and to quantify the benefit of successive interference cancellation

Characterization, Avoidance and Repair of Packet Collisions in Inter-Vehicle Communication Networks

This work proposes a combined and accurate simulation of wireless channel, physical layer and networking aspects in order to bridge the gaps between the corresponding research communities. The resulting high fidelity simulations enable performance optimizations across multiple layers, and are used in the second part of this thesis to evaluate the impact of fast-fading channel characteristics on Carrier-Sense Multiple Access, and to quantify the benefit of successive interference cancellation

A Measurement Based Shadow Fading Model for Vehicle-to-Vehicle Network Simulations

The vehicle-to-vehicle (V2V) propagation channel has significant implications on the design and performance of novel communication protocols for vehicular ad hoc networks (VANETs). Extensive research efforts have been made to develop V2V channel models to be implemented in advanced VANET system simulators for performance evaluation. The impact of shadowing caused by other vehicles has, however, largely been neglected in most of the models, as well as in the system simulations. In this paper we present a shadow fading model targeting system simulations based on real measurements performed in urban and highway scenarios. The measurement data is separated into three categories, line-of-sight (LOS), obstructed line-of-sight (OLOS) by vehicles, and non line-of-sight due to buildings, with the help of video information recorded during the measurements. It is observed that vehicles obstructing the LOS induce an additional average attenuation of about 10 dB in the received signal power. An approach to incorporate the LOS/OLOS model into existing VANET simulators is also provided. Finally, system level VANET simulation results are presented, showing the difference between the LOS/OLOS model and a channel model based on Nakagami-m fading.Comment: 10 pages, 12 figures, submitted to Hindawi International Journal of Antennas and Propagatio

Beaconing Performance in IEEE 802.11p Vehicular Networks: the Effect of Radio Channel Congestion

In this paper, we study the performance of the beaconing mechanism underlying active safety vehicular applications in presence of different levels of channel congestion. The importance of this study lies in the fact that channel congestion is considered a major factor influencing communication performance in vehicular networks, and that ours is the first investigation of the effects of congestion based on extensive, real-world measurements. The results of our study reveal that congestion has a profound impact on the most important beaconing performance metric, namely, packet (beacon) inter reception time, influencing not only the average value, but also the shape of the distribution. Congestion also considerably increases the frequency of potentially dangerous situation-awareness blackouts, with a likely negative impact on the effectiveness of active safety applications. Our study also reveals that multihop propagation of beaconing information can be used as an effective means of lessening the negative impact of congestion on beaconing performance

Radio shadowing in vehicle-to-vehicle communication at urban intersections : a measurement and simulation-based evaluation

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Multihop Beaconing Forwarding Strategies in Congested IEEE 802.11p Vehicular Networks

Abstract?Multi-hop propagation of situational information is a promising technique for improving beaconing performance and increasing the degree of situational awareness onboard vehicles. A possible way of achieving this is by piggyback information on the beacon packets that are sent periodically by each vehicle in the network, as prescribed by the DSRC and ETSI standards. However, prescribed limitations on beacon size imply that only information about a very small number of surrounding vehicles can be piggybacked in a beacon packet. In most traffic situations, this number is well below the typical number of vehicles within transmission range, implying that multi-hop forwarding strategies must be devised to select which neighboring vehicle?s information to include in a transmitted beacon. In this paper, we designed different multi-hop forwarding strategies, and assessed their effectiveness in delivering fresh situational information to surrounding vehicles. Effectiveness is estimated in terms of both information age and probability of experiencing a potentially dangerous situational-awareness blackout. Both metrics are estimated as a function of the hop distance from the transmitting vehicle, and in presence of different level of radio channel congestion. The investigation is based on extensive simulations whose multi-hop communication performance is corroborated by real-world measurements. The results show that network-coding based strategies substantially improve forwarding performance as compared to a randomized strategy, reducing the average information age of up to 60%, and the blackout probability of up to two orders of magnitude.We also consider the effect of multi-hop propagation of situational information on the reliability of a forward collision warning application, and show that network-coding based propagation yields a factor three improvement of reliability with respect to arandomized forwarding strategy, and even higher improvements with respect to the case of no propagation