Natural disasters are, unfortunately, a fundamental part of living on Planet Earth. Earthquakes, floods, tornadoes, hurricanes, and other events will continue to test the strength of the infrastructure modern society relies on, such as communication equipment like cellular networks. To effectively cope with such scenarios we have engineered a customized base station named as The Rescue Base Station (RBS); a drop-in, solar power compatible, open-source GSM communication system for scenarios where a large-scale calamity disrupts traditional modes of communication. The system operates using asynchronously connected autonomous nodes and gathers useful information from users, eventually synchronizing this data across the network using distributed network protocols. It connects people through conventional GSM services allowing calls, SMS and smart phone features when available. The networks also provides a series of services for use during a disaster, such as intelligent call routing, attribute based search on different characteristics (name, occupation and blood group), voice-mail services, SMS broadcast alerts, and emergency short-codes, through which a victim can contact available doctors, fire fighters, police and rescue workers.

1. Rescue Base Station
Ibrahim Ghaznavi, Kurtis Heimerl, Umar Muneer , Abdullah Hamid,
Kashif Ali, Tapan Parikh, Umar Saif
A drop-in communication platform
for disaster struck regions

2. Special Thanks!
OpenBTS & Freeswitch community
Endaga, Range Networks, Fairwaves
Google Faculty Research Awards
National Science Foundation- NSF

3. Disasters can happen:
Any time
Anywhere
Any magnitude

4. Kashmir Earthquake
Affected 3.5 Million

5. Indian Ocean Tsunami affected 1.7
Million people across 22 countries

6. Typical Consequences

7. Restoration can take weeks

8. Problem:
• Disruption of Information and Communication.
• Hundreds of thousands of victims in trouble.
• No way to effectively channelize the relief efforts
• Communication needs:
– Victims with victims
– Rescue workers with rescue workers
– Rescue workers with victims
– Relatives of victims with victims
• Race against time to save lives

9. Network Requirements - Base
• Quickly Deployable
• Uses Existing Phones
• Off-Grid
• Robust to node failures
• Autonomous distributed operation
– Can’t expect people to create point-to-point links

10. Network Requirements - Services
• Broadcast Announcements
• Connect people
– Victim/victim, worker/worker
– Outside/victim, victim/worker
– Intelligently, as user availability may vary
• Identify skills/resources in population
– E.g., doctors and blood type
– Searchable

11. The Big idea
• Portable, solar-powered cellular base stations
– Call, SMS and GPRS
• Different nodes establish a disconnected mesh
– Cellular network meet Sneakernet
– Users as mules to exchange data

12. The Rescue Base Station

13. Inside an RBS
• OpenBTS
• Freeswitch
• Gateway GPRS Support Node – GGSN
• Serving GPRS support Node –SGSN
• Packet Control Unit - PCU

14. How it works

15. Single RBS Unit
Coverage Range
RBS

16. User Registration
• Any user can register with our network by
sending the following information as an SMS
to 111:
– Contact Number
– Name
– Occupation
– Blood Group

17. Example

18. Eventual Consistency
• A mechanism to synchronize user registration
and call record data across the disconnected
the RBS(s)

19. Multiple RBS units working together

20. Why Eventual Consistency?
•To gather information from the neighboring
nodes and use it connect via intelligent call
routing (greater the information greater are the
chances of connectivity).
•To boost the search capability via Attribute
based search (more records synced, better
search results).
•So that the user do not have to re-register at
other neighboring RBS sites

21. Data Packet Creation
A packet is created if:
•The total number of user registrations in a BTS
is greater than 500
•Or the total registration records are less than
500 and an time-interval of 30 mins has lapsed.

22. • The packet deletion is only possible if the
number of nodes in the RBS system are fixed
• Each chuck has 2 data variables:
–Hop count
–Node count
• If the hop count equals to the node count it
means that the packet has been synced across
all the BTSes and it can be deleted.
Data Packet Deletion

23. Out-of-the-box Services
• Intelligent call routing
• Attribute based search
• Emergency voice-mail
• Emergency shortcodes
• Emergency Alerts
• Dynamic addition/ removal of RBS(es)

24. Intelligent call routing
RBS
Step 2: RBS called
User 2 who is not
available
Step 1: user1
makes a call to
user2
Step 3: RBS
automatically calls
the ‘most recent
caller’ who called
user2

25. Attribute Based Search
• An SMS based yellow page like look-up service
on the following attributes:
– Name
– Occupation
– Blood group

26. Examples: Attribute based search

27. Emergency Voice-mail
• This enable a user to record his specific
complaint directly to the rescue team (in
his/her vicinity)
• By listening to these complaints rescue teams
can be channelized in an organized fashion.

28. Emergency Shortcodes
• You may directly call the following
professionals at the following shortcodes:
– Doctors (7777 )
– Police (7700 )
– Fire brigade (7722 )
– Rescue Workers (911 )

29. Short-code Logic
Example: Doctors (7777 )
Doctor 1
Doctor 2
Doctor 3
Doctor 4
Doctor 5
Calling Doctor 1; Failed attempt
Calling Doctor 2; Failed attempt
Calling Doctor 3; Failed attempt
Calling Doctor 4; Successful attempt

30. Other Features
• Emergency Alerts: An emergency
announcement can be broadcasted to all
registered users ( in- range of the local RBS)
via an SMS.
• Dynamic addition/ removal: We can add and
remove RBS nodes to and from the system to
efficiently meet the variations in connectivity
demand of a particular disaster struck site.

32. Evaluation
• An In-Lab Experiment
• Simulations
– Nodes VS synchronizations
– Packet size VS synchronizations
– People VS synchronizations

33. Lab Evaluation

34. Lab Evaluation

35. Simulation
• All the simulation are tested on the following
two network topologies:
• Mesh topology
• Line topology

36. Nodes VS Synchronizations

37. Packet size VS Synchronizations

38. People VS Synchronizations

39. Future Work
• We are collaborating with a US based
company 'Endaga' to release a
commercial version of the Rescue Base
Station.
• We plan to (but hope not to) test it on a larger
scale in a real-world setting.

40. Important links
• Code:
https://github.com/IbrahimGhaznavi/RBS
• Project web-site:
www.rescuebasestation.com
• Contact us at:
– ighaznavi@itu.edu.pk
– info@rescuebasestation.com
– kheimerl@berkeley.edu