Sebastian Rohde

Cognitive Agent Mobility for Aerial Sensor Networks

For efficient sensor coverage of large industrial and incident areas, fast and flexible strategies for collecting sensor data through an autonomous, wirelessly connected swarm of (Micro) Unmanned Aerial Vehicles (MUAVs) are still an emerging challenge. Deploying multiple MUAVs which stably carry sensing equipment in hostile environments yields cost efficiency and reducing the risk to human life. The use of an aerial ad hoc sensor network based on MUAV agents promises more timely and accurate information by fusing measurements from different types of sensors. In this paper, we examine agent-based mobility algorithms that target high spatial coverage distribution, high total coverage, and high-quality communication links. For these key figures, the performance of the different novel mobility algorithms is evaluated. We particularly focus on channel aware mobility and on self-organizing mesh topologies of MUAV-based sensor swarms with respect to communication constraints.

Interference Aware Positioning of Aerial Relays for Cell Overload and Outage Compensation

Compensating temporary overload or site outage in cellular mobile networks is still an unsolved problem in order to avoid situations where services are unavailable. For this objective, we propose to use a swarm of Unmanned Aerial Vehicles (UAVs) equipped with cellular technology to temporarily offload traffic into neighbouring cells in LTE/4G networks. We discuss relay placement, amount of relays and relay transmit power for overload and outage compensation and provide an analytical model for evaluating system performance in the downlink. We assume that the spatial separation between the aerial service provider, users, and offload eNodeB is beneficial for temporarily increasing spectral efficiency. Our results give evidence, that aerial network provisioning can be used for optimizing mobile networks in overload and outage scenarios.

Link quality dependent mobility strategies for distributed aerial sensor networks

The in-depth reconnaissance and surveillance of incidents that are caused by uncontrolled emissions of liquid or gaseous contaminants, e.g. in cases of volcanic eruptions, large fires, industrial incidents or terrorist attacks, is still an emerging challenge. Mounting sensors on unmanned aerial vehicles (UAV) is a feasible approach since recent advances in the area of propulsion, carbon reinforced materials and batteries enable for miniaturization and cost-efficient deployment. Our proposed system makes use of an autonomous, wireless connected swarm of Micro UAVs, that is featured with a lightweight mobile sensor system. For this purpose a mobile ad hoc remote sensing network is set up in the air, that allows for calculation of potential fields like a aerosol propagation maps or 3D geomorphologies. Next to this system-of-systems approach, we uniquely show how to optimize the spatial sensor coverage while maintaining the communication quality. In this paper we analyze the equilibrium between coverage and link quality for a cluster based mobility scheme which is combined with randomized cognitive repelling walks.

AVIGLE: A system of systems concept for an avionic digital service platform based on Micro Unmanned Aerial Vehicles

Miniaturized unmanned flying robots, also referred to as MUAVs (Micro Unmanned Aerial Vehicles) open up completely new fields of innovative applications in the areas of civil security, cellular networks, surveying, entertainment and media. The AVIGLE project is based on the vision of a novel, widely applicable avionic service platform which supports multiple high-tech services by using open interfaces. Recent developments in the area of lithium polymer batteries and carbon fiber-reinforced plastic materials let MUAVs become an aerial platform, that can be equipped with a variety of sensors such as image or time of flight (ToF) cameras. Furthermore, it is also possible to mount communication technologies on the platform in order to let the MUAVs work as communication hot spots or relais at places where no cellular networks are available. In this paper we present a system of systems concept of an Unmanned Aerial System working as a service platform for different Concepts of Operations (ConOps).

SPIDER: Enabling interoperable information sharing between public institutions for efficient disaster recovery and response

The interoperability of the data sharing across different organizations is key for the efficient management of large-scale incidents. The system introduced in this paper will provide multi-disciplinary rescue teams with an integrated and intelligent communication and information system for efficient data sharing and emergency process management before, during and after major incidents. The project SPIDER (Security System for Public Institutions in Disastrous Emergency scenaRios) is part of the national research initiative Scenario based Civil Security Research and substantially funded by the German government. It will (a) facilitate a standardized XML based interface for a service oriented interoperability architecture and (b) provide substantial new insight on how to enable components in distinct critical networks for secure collaboration. With respect to (a), these interfaces will be coupled with recommendations on the orchestration of the provided services. As heterogeneous crisis information systems require standardized gateways, SPIDER uses Web Services in order to mutually interact. Thus, a fail-save communication infrastructure (b) that interconnects the required components is indispensable. Especially the usage of modern systems and the consequential high demand to the data rate pose a challenge to the system. The combination of (a) and (b) will lead to a holistic approach for digital crisis management.

Leveraging public wireless communication infrastructures for UAV-based sensor networks

Unmanned Aerial Vehicles (UAV) enable the in-depth reconnaissance and surveillance of major incidents. Uncontrolled emissions of liquid or gaseous contaminants in cases of volcanic eruptions, large fires, industrial incidents or terrorist attacks can be analyzed by utilizing UAVs (cf. Fig. 1). Hence, the use of cognitive Unmanned Aerial Systems (UAS) for distributing mobile sensors in incident areas is in general a significant value add for remote sensing, reconnaissance, surveillance and communication purposes [1][2]. Police departments, fire brigades and other homeland security organizations will have access to medium and small size UAVs in the near future and will integrate UAVs in their work flow. In this paper we are focusing on the civilian concepts of operations (CONOPS) for UAVs, in particular for small-scale UAVs. We present viable concepts on system level for leveraging public wireless communication networks for UAV-based sensor networks with respect to existing constraints and user requirements.

Experimental validation of RSS driven UAV mobility behaviors in IEEE 802.11s networks

In this research work, we describe and analyze the transition from simulation to experimental validation of communication-aware mobility behaviors for unmanned aerial vehicles (UAVs). Two reference scenarios are simulated and carried out using an experimental UAV testbed. The results are compared to determine the gap between simulation and reference implementation. In this work, we show that the received signal strength (RSS) can be used as a steering metric in communication-aware mobility behaviors. The proposed concept from simulation to outdoor experiments helps to reduce development time and failure risk due to the incremental substitution of simulated components with real implementations.

Channel Aware mobility for self organizing wireless sensor swarms based on low altitude platforms

Based on the recent developments in the area of lithium polymer batteries and carbon fiber-reinforced plastic materials Micro Unmanned Aerial Vehicles (MUAV) significantly gain in importance. The use of cognitive MUAV swarms for distributing mobile sensors is a significant value add for chemical plume detection in rescue missions and also in particular for remote sensing and surveillance purposes [1][2]. The objective of our proposed cognitive and sensor aided mesh network is to maximize the spatial sensing coverage on the one hand and the connectivity between the cooperative MUAVs on the other. Next to these contrary optimization goals we developed bio-inspired algorithms seeking concurrently for a global target and a coherent topology of the swarm in order to avoid self-separations. In this paper we particularly focus on an agent-based methodology for communication aware mobility behavior of self-organizing MUAVs at high vehicular speeds which provoke fast topology changes and lead to a transient aerial mesh network. To determine the key figures of the system, the performance of dynamically adapted mobility algorithms is analyzed and compared under lognormal channel conditions.

Performance Evaluation for Mobile WiMAX Handover with a Continuous Scanning Algorithm

With the IEEE 802.16e standard for MobileWiMAX the course for new 4G mobile radio communication systems is set. It offers significantly higher data rates than GSM orWCDMA/UMTS and supports different handover mechanismsand QoS features in contrast to WiFi (IEEE 802.11g) on theOSI-layer 2 (L2). Since WiMAX-devices are hardly availabletoday and protocol optimizations are strongly restricted with commercially available devices, a simulation model is not far to seek. Thus, we developed and implemented a simulation in OMNeT++ based on the INET framework in order to investigate and evaluate the performance of the new Mobile WiMAX protocol. In this paper we particularly focus on the handover performance on OSI-Layer 2 (L2) for noise affected channels. Beyond the standardized handover we propose a sliding window mechanism for the channel measurements the handover decision is based on. Ultimately a performance evaluation demonstrates the reductionof handover delay for certain noise levels by introducing acontinuous scanning process.

Communication constrained mobility and topology management for relay sensor networks

In this paper we propose distributed algorithms that solve the coverage problem in 3D space. In particular, we use a swarm of unmanned aerial vehicles (UAVs) in order to explore a possibly unknown area. Actual use cases include the automated acquisition of sensory data in operations that try to gain extensive knowledge about an area. First, we try to efficiently cover a predefined 3D space with multiple UAVs. Second, we target to maintain intra-swarm connectivity during the whole operation. Consequently, we develop and enhance metrics for benchmarking the resulting system with respect to coverage and communication capabilities. The algorithms were optimized towards getting a quick overview that is iteratively refined by getting more accurate data. This principle is similar to mip-mapping in computer graphics.