Over the years peer-to-peer (P2P) multi-hop relays have been studied for mobile ad-hoc networks (MANETs) to overcome poor signal coverage and to improve connectivity. However, for an urban environment, particularly with a sparse mobile distribution, a ground relay is not able to achieve significant benefits, mainly due to the extremely high pathloss and shadowing encountered. Dedicated airborne relay nodes, at a height of hundreds or thousands of meters, can provide much better coverage, and hence improve the connectivity, decrease the number of hops, reduce the power consumption, and support co-operative relays when integrated into mobile ad-hoc networks. An air node can also act as the sink for current wireless sensor networks (WSNs). Despite these potential advantages, the coverage from an air node located directly above an urban operating environment has not been adequately investigated in the literature. This paper compares the advantages of airborne relaying compared to more conventional peer-to-peer mobile relays. Three channel types are considered, i.e. line-of-sight (LoS), obstructed LoS (OLoS), and non-LoS (NLoS), each with their own likelihood, pathloss, and shadowing models. The practical gain pattern of a hemispheric antenna, or a directional antenna, is also carefully considered for the air node. Comparisons of the air-to-ground (A2G) channel and the mobile P2P channel demonstrate that airborne relays can enhance the coverage and reduce the power consumption significantly.
"However, we identify the need to take communication constraints into account. Though enhancing the coverage with respect to power consumption in an airborne relay network in , autonomous agents and CPT stay unregarded. A communication-aware strategy incorporates communication link qualities, such as SNR into the motion-planning function . "
[Show abstract][Hide abstract] ABSTRACT: Efficient aerial plume detection has gained great significance in the area of systematic environmen-tal monitoring. Disaster situations like volcano erup-tions, major industrial incidents or large fires demand for an in-depth analysis of the emitted contaminants and air quality. Deploying MUAV which stably carry sensing equipment in hostile environments yields re-ducing the risk to human life and cost efficiency. 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 sen-sors. In this paper we compare two steering strategies, namely self repelling random walk (SRW) and coopera-tive repelling random walk (CRW), to efficiently cover a region of interest. We also combine these steerings with concepts to maintain MUAV swarm coherence and analyze the RSSI and throughput.
[Show abstract][Hide abstract] ABSTRACT: 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.
Wireless Communications and Networking Conference (WCNC), 2011 IEEE; 05/2011
[Show abstract][Hide abstract] ABSTRACT: 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 ac- curate information by fusing measurements from different types of sensors. In this paper, we examine agent-based mobility algo- rithms 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.
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