Interview Questions › Product Design

Design an offline emergency disaster communication and rescue platform

Design a resilient peer-to-peer mobile application and first-responder coordination platform for disaster zones (earthquakes, hurricanes) where cellular towers, power grids, and internet backhauls are completely destroyed.

Context

Following catastrophic natural disasters, victims are trapped without cell service, while first responders operate blind without real-time casualty heatmaps or infrastructure damage data.

Clarifying questions to ask first

• How do mesh messages travel without internet? (Multi-hop BLE / Wi-Fi Direct mesh hopping between citizen smartphones).
• How are emergency medical priorities categorized? (Standard Red/Yellow/Green/Black triage flags).

How to approach it

1. Severe Physical Constraints: Zero cellular reception, dead internet, rapidly draining phone batteries, debris physical hazards, medical triage urgency
2. Design Peer-to-Peer Offline Mesh Communication Architecture:
3. 1. Bluetooth Low Energy & Wi-Fi Direct Multi-Hop Mesh (Messages hop securely phone-to-phone across up to 30 intermediate devices until reaching a satellite terminal or rescue station)
4. 2. "Ultra-Low Power Beacon Mode" (Turns off phone screen and broadcasts BLE SOS packet every 30 seconds with 5-day battery life)
5. 3. First Responder Triage Dashboard (Rescue helicopters and drones flying overhead collect mesh packets and render live survivor location heatmaps)
6. 4. Offline First-Aid & Water Purification Interactive Guides

Framework: Disaster Failure Modes -> P2P Multi-Hop Mesh Networking -> Ultra-Low Power SOS Protocols -> First Responder Tactical Dashboard -> Rescue Operations Metrics

Sample answer

• Assuming internet connectivity in a disaster is a fatal flaw; true resilience requires multi-hop peer-to-peer ad-hoc mesh networking
• Phones buried under rubble must be able to beacon their GPS coordinates for 96+ hours on 15% battery

1. MVP: P2P Bluetooth mesh chat, 1-tap SOS distress beacon with medical status, offline vector terrain map, and airborne drone mesh-relay packet harvester

Executive design: A zero-infrastructure disaster communication network leveraging multi-hop smartphone Bluetooth mesh protocols, ultra-low-power survivor beacons, and airborne tactical triage heatmaps.

What interviewers look for

• Zero-Infrastructure P2P Mesh Network Protocol UX
• Extreme Battery Conservation Engineering
• First Responder Triage Prioritization (START triage system)
• Offline Geographic Map Storage