TY - GEN A1 - Chatharajupalli, Navya Sneha A1 - Rotta, Randolf A1 - Karnapke, Reinhardt A1 - Nolte, Jörg T1 - Assessing the Feasibility of Combined BLE and Wi-Fi Communication for High Data Sensing Applications T2 - EWSN '23: Proceedings of the 2023 International Conference on Embedded Wireless Systems and Networks N2 - Advanced sensors generate more data than can be transmitted using classic battery-powered wireless sensor networks. While using Wi-Fi would provide plenty of throughput, the receivers are energy hungry and, thus, the radio time needs to be reduced. Previous research suggests to combine Wi-Fi with low-power technologies such as BLE for an energy efficient coordination of the Wi-Fi radios. Existing approaches focus on individual point-to-point routes whereas certain applications require concurrent transmissions. We evaluated the combination of BLE and Wi-Fi on the ESP32-S3 multi-radio microcontroller through detailed energy and throughput measurements. The results show that established BLE connections allow to activateWi-Fi quickly on-demand; the energy efficiency of the data transmission is significantly improved over previous works but the BLE connection setup is prohibitively slow. While the combination of BLE and Wi-Fi provides high throughput with good energy efficiency, careful design of the BLE-based signalling protocol is necessary to also achieve low latency. Y1 - 2023 U6 - https://doi.org/10.5555/3639940.3639948 SP - 56 EP - 59 PB - Association for Computing Machinery CY - New York ER - TY - CHAP A1 - Chatharajupalli, Navya Sneha A1 - Rotta, Randolf A1 - Nolte, Jörg T1 - P2 - VibroMote: Energy efficient Vibration Monitoring for Railway tracks and Bridges T2 - iCCC2024 - iCampµs Cottbus Conference 2024-05-14 - 2024-05-16 N2 - Filtering, storing, and transmitting measurements of high-resolution sensors within a limited energy budget is challenging. For instance, a 3-axis MEMS acceleration sensor for structural condition monitoring and predictive maintenance generates up to 160 kB/s at a sampling rate of 26.6 kHz. This paper discusses the design space with focus on solar harvesting solutions. VibroMote is an energy efficient sensor node that combines a multi-radio micro-controller, an ultra-low power co-processor with persistent memory, a solar harvester, and multiple energy storage options. This enables prototyping of solar-powered long-term data acquisition, in-node processing, and wireless networking for high-resolution sensors. KW - structural condition monitoring KW - predictive maintenance KW - energy efficiency KW - solar harvesting Y1 - 2024 SN - 978-3-910600-00-3 U6 - https://doi.org/10.5162/iCCC2024/P2 SP - 123 EP - 126 PB - AMA Service GmbH, Von-Münchhausen-Str. 49, 31515 Wunstorf, Germany ER - TY - GEN A1 - Rotta, Randolf A1 - Chatharajupalli, Navya Sneha A1 - Naumann, Billy A1 - Schulz, Julius A1 - Karnapke, Reinhardt A1 - Werner, Matthias A1 - Nolte, Jörg T1 - Demo: B.A.T.M.A.N. mesh routing on ultra low-power IEEE 802.11 modules T2 - 2024 IEEE 49th Conference on Local Computer Networks (LCN) N2 - When implementing multi-hop mesh network protocols, efficient direct communication, route discovery, and route repair are crucial to achieve high network throughput. To our knowledge, there is no open mesh routing protocol available for ultra low power IEEE 802.11 modules. Previous work relied on single board computers like Raspberry Pi. We implemented the B.A.T.M.A.N. mesh protocol on the popular Espressif ESP32 along with a novel hybrid rate adaptation for the selection of efficient routes. In this demo we showcase challenges and solutions related to the implementation on ESP32 and how the hybrid rate adaptation improves end-to-end throughput. KW - ad-hoc networks KW - mesh networks KW - low power electronics KW - throughput Y1 - 2024 SN - 979-8-3503-8800-8 U6 - https://doi.org/10.1109/LCN60385.2024.10639789 SN - 2832-1421 PB - IEEE ER - TY - GEN A1 - Rotta, Randolf A1 - Schulz, Julius A1 - Naumann, Billy A1 - Chatharajupalli, Navya Sneha A1 - Nolte, Jörg A1 - Werner, Matthias T1 - B.A.T.M.A.N. Mesh Networking on ESP32’s 802.11 T2 - 2024 IEEE 49th Conference on Local Computer Networks (LCN) N2 - Mesh routing protocols are widely used in IoT and sensor networks. In recent years, the ESP32 Wi-Fi/BLE SoC became popular for prototyping IoT applications. However, the existing mesh networks for this platform lack efficient node to node communication, fast route discovery and repair, and energy efficiency. This paper addresses the formation of IEEE 802.11 based ad-hoc mesh networks without the delays inflicted by the Station to Access Point association protocol. We implemented the B.A.T.M.A.N. protocol on top of the ESP32 Wi-Fi MAC interface and integrated it into the LwIP network stack. The performance evaluation with respect to UDP/IP and TCP/IP end-to-end throughput shows the general usefulness but also identifies bottlenecks caused by limitations of the existing MAC interface. Overall, this opens an interesting opportunity for research on mesh protocols by providing a simpler platform than full featured Wi-Fi routers; and for wireless IoT applications by providing higher throughput than subGHz and BLE technologies. KW - wireless communication KW - mesh networks KW - wireless sensor networks KW - routing protocols Y1 - 2024 SN - 979-8-3503-8800-8 U6 - https://doi.org/10.1109/LCN60385.2024.10639698 SN - 2832-1421 SN - 2831-7742 SP - 1 EP - 7 PB - IEEE ER - TY - GEN A1 - Chatharajupalli, Navya Sneha A1 - Rotta, Randolf A1 - Karnapke, Reinhardt A1 - Nolte, Jörg T1 - Probing considered harmful : leveraging RSSI for link quality prediction T2 - Proceedings of the IEEE 50th Conference on Local Computer Networks : LCN 2025 : October 14-16, 2025, Sydney, Australia N2 - Wireless mesh protocols that use a routing metric based on throughput or airtime require predictions about future throughput for all mesh neighbors. Typically, the Wi-Fi rate controller provides this information, and state-of-the-art rate control algorithms estimate it based on statistics from past unicast transmissions. This introduces an adverse cross-layer dependency because meaningful statistics are only available for the links that were used by the routing layer. Existing implementations either ignore this, or use other routing metrics, such as distance, or generate artificial periodic probe traffic to all neighbors. Unfortunately, probing reacts slowly to changing conditions, increases the medium contention, and can lead to overly optimistic predictions. To overcome this, we introduce an RSSI-based link quality prediction for the routing layer. Benchmarks in a B.A.T.M.A.N. version V mesh show a decrease of round-trip time by three orders of magnitude and an increase of the end-to-end packet delivery ratio. TCP connections became possible over long routes that were previously unusable. Although highly imprecise, the easy to acquire RSSI provided sufficiently good predictions for our mesh network. KW - Wireless Mesh Network KW - Multi-hop routing KW - Neural Networks KW - Machine Learning KW - Link quality predictors Y1 - 2025 SN - 979-8-3315-3704-3 U6 - https://doi.org/10.1109/LCN65610.2025.11146347 SN - 2831-7742 SP - 1 EP - 9 PB - IEEE CY - New York, NY ER - TY - GEN A1 - Chatharajupalli, Navya Sneha A1 - Rotta, Randolf A1 - Karnapke, Reinhardt A1 - Nolte, Jörg T1 - Animal health monitoring and tracking through solar-powered mesh network T2 - 22. GI/ITG KuVS Fachgespräch Sensornetze : 11. und 12. September 2025, Clausthal-Zellerfeld N2 - Various health and movement sensors, especially bolus sensors inside a cow’s stomach, are crucial for timely medical interventions. Commonly, wall-powered gateways are used to retrieve sensor updates and forward them quickly to an analysis service. In large outdoor farmlands, however, localisation of individual cows becomes important while the long-term operation of wall-powered gateways is costly. Previous solutions that use a LoRaWAN gateway with bigger antennas are still limited to 500m and provide only poor localization information. Existing solutions based on a mesh network of repeaters provide good localization but still depend on external wall power. Solar-powered mesh nodes would simplify the long-term operation. In order to achieve this, a significant improvement of the energy efficiency of the mesh nodes is necessary. This paper explores protocol design choices for the energy-efficient communication between mesh nodes and the bolus sensors. By introducing synchronised sleep and communication intervals, the size of the solar panels and energy storage can be reduced. KW - Wireless Networks KW - Solar-harvesting KW - Localisation Y1 - 2025 UR - https://dokumente.ub.tu-clausthal.de/receive/clausthal_mods_00002954 U6 - https://doi.org/10.21268/20250805-0 SP - 1 EP - 3 PB - TU Clausthal-Zellerfeld CY - Clausthal-Zellerfeld ER - TY - GEN A1 - Chatharajupalli, Navya Sneha A1 - Rotta, Randolf A1 - Karnapke, Reinhardt A1 - Nolte, Jörg T1 - VibroMote : Wi-Fi-based mesh communication for railway bridge inspection and monitoring T2 - 2025 International Symposium on Networks, Computers and Communications (ISNCC) N2 - Vibration sensing provides insights into the dynamic behaviour of engineering constructions such as railway bridges. Cable-based sensors are viable only for long-term condition monitoring and rare special inspections because of the labor-intensive deployment. Although wireless sensors significantly reduce this overhead, their energy constraints limited the network throughput and, hence, their resolution in space and time. Batteryor solar-powered sensor nodes with high network throughput would enable in-depth measurements during regular inspections and improve the access to high-quality monitoring data. We present “VibroMote”, which combines energy harvesting, a high-bandwidth 3-axis MEMS accelerometer, and high-throughput, self-organizing mesh communication via IEEE 802.11 Wi-Fi. The evaluation on a real bridge with 18 VibroMotes shows that the deployment time can be reduced from hours to minutes; the multi-hop mesh provides sufficient throughput reserves for the application whereas direct one-hop communication failed; the battery runtime is sufficient for temporary measurements during inspections; and the energy consumption during sleep modes would be low enough for solar-powered long-term monitoring. Hence, the combination of high-throughput Wi-Fi with mesh networking is a strong alternative to the commonly used low-power radio technologies when long range between the sensors is not needed. KW - Wireless Mesh Network KW - Condition Monitoring KW - Multi-hop routing KW - Wi-Fi Mesh Y1 - 2025 SN - 978-1-6654-5769-9 U6 - https://doi.org/10.1109/ISNCC66965.2025.11250402 SN - 2768-0940 SP - 1 EP - 6 PB - IEEE CY - Piscataway, NJ ER -