Department Publications

Voice communication is essential in post-disaster scenarios where users may be unable to type due to injury, stress, or environmental constraints. While Meshtastic provides a decentralized LoRa-based mesh network for long-range messaging, it does not natively support voice and is limited by low data rates and strict regulatory duty-cycle requirements. This paper investigates two methods for enabling voice over such networks: waveform-based audio packetization and a semantic speech-to-text (STT)/text-to-speech (TTS) approach. Preliminary experimental evaluations demonstrate that waveform-based methods, even when using low-bitrate codecs like Codec2, are impractical for urgent communication; delivering a 3-second voice message requires hundreds of packets and several minutes due to ransmission latency and duty-cycle constraints. In contrast, the proposed offline STT/TTS method transcribes speech locally, transmits it as a standard text payload, typically in a single packet and reconstructs the audio at the receiver. This semantic approach reduces delivery time from minutes to seconds, while maintaining high reliability and regulatory compliance. The study concludes that semantic communication is the most viable solution for voice interaction in bandwidth-constrained LoRa mesh environments.

This work presents the development of an opensource standalone (SA) 5G testbed with end-to-end slicing, using open-source software on commercial off-the-shelf (COTS) hardware and software-defined radio (SDR). Key contributions include customized slice configurations in the 5G Core Network (5GC) and dedicated static resource allocation in the radio access network (RAN). The testbed is validated through slice isolation tests. Its utility is then demonstrated via a warehouse application featuring Automated Guided Vehicles (AGVs) on one slice and environmental sensors & actuators on another. Critical AGV response times are evaluated under mixed traffic conditions, showing robust slice isolation and superior performance over baseline networks. The testbed offers a scalable, cost-effective platform for 5G education, research, and application testing. It also highlights the transformative potential of such open …

The deployment of 5G networks using open-source software platforms on commodity hardware and software defined radios (SDRs) has become increasingly important for both research and prototyping. Most work is constrained to a single platform such as OpenAirInterface (OAI), inhibiting the potential for cross-platform trade-offs. This paper presents Open5GFusion, a heterogeneous 5G Standalone (SA) testbed that combines OAI, srsRAN, and Open5GS to enable flexible experimentation with different core network (CN) and radio access network (RAN) alternatives and to exploit the strengths of each. A graphical user interface (GUI) simplifies deployment management and monitoring across different CN/RAN combinations. The testbed leverages commercial off-the-shelf (COTS) hardware with USRP B210 and N310 SDRs, allowing real-time evaluation of throughput, latency, modulation schemes, network slicing …