Design and Implementation of a Low Cost and Resilient Wireless Network for First Response Communications

Design and Implementation of a Low-Cost and Resilient Wireless Mesh Network for

First-Response Communications

Nestor Michael C. Tiglao, PhDAngelie A. Dela Cruz

Miguel Luis A. ParabuacUbiquitous Computing Laboratory - EEEI

University of the Philippines Diliman

Presentation Outline- Introduction- Review of Related Works- Problem Statement and Objectives- Methodology- Results and Discussion- Conclusions- Recommendations

Outline | 01

Introduction- Disaster relief and response in

the Philippines is lacking and unreliable

Introduction | 02

Introduction

Introduction | 03

Review of Related Works- Network Technology: WiFi 802.11n/s- Routing Protocol: Batman-adv- Chat Messaging App: Android-based- Messaging Protocol: MQTT

Review of Related Works | 04

Problem Statement● Lack of proper communication in disaster scenarios● Consider when text messaging is unavailable● A reliable and cheap communication platform is needed● Retrieve messages sent while the user was away (caching

feature)

Problem Statement | 05

Objectives● Design and implement a wireless mesh network comprised

of Raspberry Pis● Develop a chat messaging Android app● Integrate the infrastructure network with the application● Implement caching

Objectives | 06

Methodology

Network Infrastructure

Methodology | 07Figure 1: A fully-working wireless mesh network

Android Chatting Application- Android Studio- PAHO MQTT Library- Android 2.1+

Methodology | 08

Testing Phase- Functionality

- Messaging- Caching Feature

- Resilience- Self-healing- Self-configuration

- Internet “sharing”

Methodology | 08

Results and Discussion

Ad-Hoc Networkiwconfigwlan1 IEEE 802.11bgn ESSID:RasPi

Mode:Ad-HOc Frequency:2.427GHz Cell:02:12:34:56:78:9A Tx-POwer=20 dBm Retry short limit:7 RTS thr:off Fragment thr:off Power Management:off

R Pi 1

R Pi 2

R Pi 3

R Pi 4

Figure 2: ‘RasPi’ ad-hoc network

Results and Discussion | 09

Mosquitto Brokers

type / receiver / sender / time_stamp / node

Results and Discussion | 10

Mosquitto Bridges

RPi 1

RPi 2

RPi 3

RPi 4

+/+/+/+/node1

+/+/+/+/node1

+/+/+/+/node1

+/+/+/+/node3

+/+/+/+/node3+/+/+/+/node3

+/+/+/+/internet

+/+/+/+/internet

+/+/+/+/internet

+/+/+/+/node2

+/+/+/+/node2

+/+/+/+/node2

Figure 3: Topic matching for the mosquitto bridges

Results and Discussion | 11

Messages To/From Internet

RPi 4 Internet

+/+/+/+/node1+/+/+/+/node2+/+/+/+/node3

+/+/+/+/internet

Figure 4: Topic matching for internet messaging

Results and Discussion | 12

Rerouting Using Batman-adv

BATMAN-adv nodes:

c8:3a:35:c8:97:31c8:3a:35:c0:3a:1dc8:3a:35:c1:44:90c8:3a:35:ca:68:70

Results and Discussion | 13

Rerouting Using Batman-adv

RPi1 RPi2 RPi3

Results and Discussion | 13

Rerouting Using Batman-adv

RPi4

RPi2

RPi1

RPi3

Results and Discussion | 14

Rerouting Using Batman-adv

RPi4

RPi2

RPi1

RPi3

Results and Discussion | 15

Rerouting Using Batman-adv

RPi4

RPi2

RPi1

RPi3

Results and Discussion | 16

Rerouting Using Batman-adv

RPi4

RPi2

RPi1

RPi3

Results and Discussion | 17

Crisis Chat Mobile App- Two Modes

- Internet (as Rescuer)- AdHoc (local)

- Messaging- MQTT QoS2

- Caching Feature- Receive messages even if user is

offline- AdHoc Mode

- Detects nearest Raspberry Pi

Results and Discussion | 18

Conclusion and Recommendations

Conclusion- We have proven that we can make a low-powered, reliable,

and cheap wireless mesh network using Raspberry Pi nodes.- The messages in the network are cached for future use.- We devised a way to tag messages for the bridge

configuration- Established bidirectional communication with the internet- The project is 100% complete.

Conclusion and Recommendations | 19

Problems Encountered- Linux driver problems- Android problems

- Does not support ad-hoc connectivity- Does not instantly return WiFi scan results

- Testing phase

Conclusion and Recommendations | 20

Recommendations- More features and material design on chat messaging app- Create/port an iOS equivalent (Android <-> iOS

communication)- Subject the network to heavier load- Deploy in an actual community

Conclusion and Recommendations | 21

Thank You!