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Throughout recent decades, infrastructure failures due to natural disasters and political disruptions have repeatedly rendered traditional communication networks unavailable. In these contexts, affected populations are often unable to contact emergency services, coordinate relief efforts, or communicate with family members. In response to these conditions, a student research team developed High Altitude Long-Range Networking (HALoN) for Crisis Communication, a LoRa-based mesh communication system intended to provide temporary connectivity in times of need.

HALoN is designed to support the transmission of short text messages and location data using low-cost, low-power hardware. The system operates as a decentralized mesh network composed of grounded nodes and, in an ideal deployment, high-altitude balloon relays. Meant to temporarily replace conventional communication systems, HALoN does not rely on cellular infrastructure, internet connectivity, or licensed spectrum. It operates in the unlicensed 900 MHz ISM band and is built using consumer-accessible microcontrollers compatible with the Arduino ecosystem.

These design choices aim to enable temporary access to communication infrastructure, particularly for communities and organizations that lack the resources or regulatory permissions required for traditional alternative  systems. At the same time, these choices introduce technical constraints. LoRa communication is characterized by low bandwidth and simplex operation, requiring nodes to coordinate transmission opportunities carefully to avoid collisions and inefficient use of limited airtime.

To manage this, HALoN implements a priority aware, queue-learning scheduling algorithm in which each node maintains a queue of messages it has received. At each transmission window, the node evaluates packets based on factors including retransmission count, link quality, queue congestion, message priority, age, and size. Messages are then selected for transmission according to a learned scoring model. This approach was developed in part to address limitations observed in simpler scheduling strategies such as First-Come First-Served and Shortest Job First, which may lead to congestion, inefficiency, or systematic delays for certain messages.

In addition, HALoN includes a lightweight acknowledgment mechanism intended to inform users whether a message has been successfully delivered. Messages are retransmitted if no acknowledgment is received, up to a fixed limit of 3 retransmissions, after which the system reports failure.

During development, the system was evaluated primarily in controlled or simulated environments. These evaluations demonstrated the feasibility of multi-hop communication and adaptive scheduling under constrained conditions. However, the system has not yet been tested extensively in real-world disaster scenarios characterized by high interference, unstable topology, and unpredictable node behavior.

Researchers working with similar systems have noted that performance under controlled conditions may differ significantly from performance in deployment environments. In HALoN’s case, operation in a shared frequency band introduces the possibility of interference from other devices (and likewise, interfering with other devices), while reliance on balloon-based relays introduces variability due to drift and changing line-of-sight conditions. These factors may affect message delivery reliability, particularly during periods of high contention or network reconfiguration. 

At the same time, the system currently transmits messages without encryption and does not include built-in mechanisms for sender authentication. As a result, messages can be intercepted by any actor with compatible hardware, and false messages may be introduced into the network without verification of origin. In scenarios involving vulnerable populations or sensitive information, such as location data, these characteristics may carry additional risks.

The scheduling framework introduces further complexity. Because message prioritization depends on dynamic conditions such as link quality and retransmission history, some messages may be delayed repeatedly under adverse network conditions. While the system incorporates mechanisms intended to prevent indefinite delay, users are not provided with direct visibility into how scheduling decisions are made or why particular messages are deprioritized.

HALoN’s accessibility via its use of low-cost hardware, unlicensed spectrum, and decentralized deployment also makes it possible for a wide range of organizations to deploy the system. This includes organizations with varying levels of technical expertise and differing understandings of the system’s limitations.

For now, HALoN remains a research prototype. Its designers have identified several areas for further development, including encryption, authentication, and additional field testing. At the same time, the system illustrates broader questions about the deployment of communication technologies in high-stakes environments, particularly when reliability, access, and transparency are all constrained.

Discussion Questions:

1. Who are the stakeholders involved in the development, deployment, and use of HALoN? Who should be consulted in discussions about when and how such systems are deployed in crisis contexts?
2. How might the design and deployment of HALoN be evaluated through the lenses of rights, justice, utilitarianism, the common good, virtue ethics, and care ethics? See the Markkula Center for Applied Ethics’s Framework for Ethical Decision Making for reference. 
3.  What ethical challenges might arise in the interactions between system designers, deploying organizations, and users?