Leveraging multiple simultaneous small cell connections is an emerging and promising solution to enhance session continuity in millimeter-wave (mmWave) cellular systems that suffer from frequent link interruptions due to blockage in ultra-dense urban deployments. However, the available performance benefits of feasible multi-connectivity strategies as well as the tentative service quality gains that they promise remain an open research question. Addressing it requires the development of a novel performance evaluation methodology, which should consider: 1) the intricacies of mmWave radio propagation in realistic urban environments; 2) the dynamic mmWave link blockage due to human mobility; and 3) the multi-connectivity network behavior to preserve session continuity. In this paper, we construct this much needed methodology by combining the methods from queuing theory, stochastic geometry, as well as ray-based and system-level simulations. With this integrated framework, both user- and network-centric performance indicators together with their underlying scaling laws can be quantified in representative mmWave scenarios. To ensure modeling accuracy, the components of our methodology are carefully cross verified and calibrated against the current considerations in the standards. Building on this, a thorough comparison of alternative multi-connectivity strategies is conducted, as this paper reveals that even simpler multi-connectivity schemes bring notable improvements to session-level mmWave operation in realistic environments. These findings may become an important reference point for subsequent standardization in this area.

In logistic services there often are pick-up and delivery time window constraints specified by logistics customers. Our study was to find a solution to manage huge amount of data to enable data processing when calculating shortest or most productive routes for vehicles. The solution allows different kinds of restrictions for the application area and it is adaptable in several services such as healthcare offered at home, postal services or carrying schoolchildren. Design science research was applied to build the output that relied heavily on mathematical approach.

Vehicular ad hoc networks using WLAN technology have recently received considerable attention. We present a position-based routing scheme called Connectivity-Aware Routing (CAR) designed specifically for inter-vehicle communication in a city and/or highway environment. A distinguishing property of CAR is the ability to not only locate positions of destinations but also to find connected paths between source and destination pairs. These paths are auto-adjusted on the fly, without a new discovery process. "Guards" help to track the current position of a destination, even if it traveled a substantial distance from its initially known location. For the evaluation of the CAR protocol we use realistic mobility traces obtained from a microscopic vehicular traffic simulator that is based on a model of driver behavior and the real road maps of Switzerland.

Vehicular ad hoc networks (VANETs) using WLAN tech-nology have recently received considerable attention. The evaluation of VANET routing protocols often involves simulators since management and operation of a large number of real vehicular nodes is expensive. We study the behavior of routing protocols in VANETs by using mobility information obtained from a microscopic vehicular traffic simulator that is based on the on the real road maps of Switzerland. The performance of AODV and GPSR is significantly in uenced by the choice of mobility model, and we observe a significantly reduced packet delivery ratio when employing the realistic traffic simulator to control mobility of nodes. To address the performance limitations of communication pro-tocols in VANETs, we investigate two improvements that increase the packet delivery ratio and reduce the delay until the first packet arrives. The traces used in this study are available for public download.

This research was supported, in part, by the NCCR "Mobile Information and Communication Systems", a research program of the Swiss National Science Foundation, and by a gift from the Microprocessor Research Lab (MRL) of Intel Corp.An ad hoc network is formed by wireless mobile nodes (hosts) that operate as terminals as well as routers in the network, without any centralized administration. Research in ad hoc networks often involves simulators since management and operation of a large number of nodes is expensive. However, the widely used simulator NS-2 does not scale; it is very hard to simulate medium scale networks with 100+ nodes. We describe here improvements to NS-2 to meet the needs of large ad hoc network simulations. The modified NS-2 simulator is based on the idea of exploiting the limited interference of wireless communication. The modified simulator has simulated populations of up to 3000 nodes so far and works up to 30 times faster than the original version. We also discuss how the modified simulator is validated.