Condroid WSN/DTN Gateway - System Architecture & Requirement

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2011 SUMMER CSD

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Lan Sun ([email protected]), 15 ECTS

Qing An ([email protected]), 15 ECTS

Jun Gao ([email protected]), 15 ECTS

Laili Aidi ([email protected]), 18 ECTS

Yasir Ali ([email protected]), 15 ECTS

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WSN/DTN Gateway System Architecture & Requirement V1.0

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Revision History

Version Date Responsible Change

V1.0 2011-10-10 Qing An and Laili Aidi Initial version of the document


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Contents

Contents.....................................................................................................................................................3

Summary....................................................................................................................................................4

Abbreviation ..............................................................................................................................................5

1. System Architecture ...............................................................................................................................6

2. System Requirement..............................................................................................................................8

2.2 Hardware Requirement .............................................................................................................................................. 8

2.3 Software Requirement................................................................................................................................................ 8

3. Software Design................................................................................................................................... 12

4. References............................................................................................................................................ 18


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Summary

This document describes the System Architecture, System Requirement and Software Design of the

WSN/DTN Gateway, including the features and class diagram of the WSN/DTN Gateway Engine

applications


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Abbreviation

Abbreviations used in this document:

Abbreviation Description

MySQL An Open source Relational database management system (RDBMS)

ALIX Board Single board computer capable of running operating systems

SunSPOT Embedded microprocessor that runs Java

Voyage Linux GNU/Linuxderived distribution that is best run on a x86 embedded platforms

Barkeley DB Software library that provides embedded database for key/value data

USB Universal Serial Bus

WPA Wi-Fi Protected Access

Wi-Fi Trademark of a product based on IEEE 802.11

Apache HTTP Server

PHP Hypertext Preprocessor, Server-side HTML embedded scripting language


Dnsmasq Lightweight version to configure DNS forwarder and DHCP server.

JDK Java Development Environment

Apache Ant XML-based build scripting language

Hald HAL Daemon

SunSPOT Embedded microprocessor that runs Java

DHCP Dynamic Address Allocation Protocol

AP Access-Point

DNS Domain Name System

ProPHET Probabilistic Routing Protocol using History of Encounters and Transitivity

Wi-Fi Trademark of a product based on IEEE 802.11

DTN Delay Tolerant Network / Delay Disruptive Network

WSN Wireless Sensor Network

DTN Delay Tolerant Network / Delay Disruptive Network


Bytewalla Implementation of DTN in the Android platform.


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1. System Architecture One of the Condroid CSD project aim is to design, implement and analyze the performance of

WSN/DTN Gateway, which is intended to solve the technical issues in carrying the data from the spatially

distributed autonomous WSN motes to the outside world [1, 2, 3]. The WSN motes are deployed to monitor

physical or environmental conditions, connected to a WSN Gateway, which collects the information received

from nodes, stores them in a database, and provides interfaces between the sensor network and the external

network infrastructure, by making make them available via WiFi link and Bytewalla [4, 5, 6, 7].

Below is the design of system architecture of this WSN/DTN Gateway in its complete scenario:

Figure 1. WSN/DTN Gateway System Architecture design


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The figure above shows the WSNs deployed in remote area with no Internet connectivity (Village

network). The sensors in each network continuously broadcast the sensor data, and the Base station passes the

data it receives from the sensor within its area to the WSN/DTN Gateway, which then log this data in the

database.

The WSN/DTN Gateway is also equipped with WiFi Access point, which makes it enable to be reached

by the user both for accessing the data directly through its Web-base interface or for tapping the bundle sensor

data. Using the WSN/DTN Gateway Web-base interface, user can see these sensor data in the table format,

analyze it using graph, or even download it.

The WSN/DTN Gateway also continuously generate the sensor data in specific range of time into DTN

bundle, so these bundles ready to be forwarded to any DTN node within the range of the WiFi AP of the

WSN/DTN Gateway. The DTN bundle generation also possible to be triggered by user using the Web-based

Interface.

The Bytewalla phone plays the role as the postman of these sensor bundle, that carry these data and

forward it to another DTN node until this bundle reach the destination in the City Network, either trough

cellular network or direct link (WiFi Access Point) of the City WSN/DTN Gateway.

After the sensor bundle received in the City WSN/DTN Gateway, it then possible to be accessed by the

user using the same Web-base Interface platform that is deployed in Village WSN/DTN Gateway. The Village

WSN/DTN Gateway implement data compression to the sensor data before it is sent as DTN bundle in order

to optimize the resource, where the City WSN/DTN Gateway then un-compress it again when receives this

DTN bundle.


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2. System Requirement In this section, we give a detail description of the components of this system, including the hardware

requirements and software that require implementing or simulating the complete WSN/DTN Gateway system.

2.2 Hardware Requirement

The hardware requirements of the WSN/DTN Gateway are listed below:

1. ALIX Board with sufficient power Supply

The ALIX Board is the SBC that highly power efficient, small and capable to run operating system. It is

used as the WSN/DTN Gateway hardware, where the system running on top of is [8].

2. WSN mote(s)

The Mote(s) is the embedded hardware with sensor and small battery which make it enable to collect the

data about physical or environmental conditions and broadcast / multicast it to the Base station. In this

WSN/DTN Gateway system we use the SunSPT mote that work based on IEEE 802.15.4 standard on the

Squawk JVM, run directly on the processor without an OS [9].

3. WSN Base station

The Base station is used to receive the data that is broadcasted / multicasted by the WSN Mote(s), which

the then directly passed to the WSN/DTN Gateway by the Base station. As same as the motes, we also use

SunSPOT to implement this WSN/DTN Gateway system [9].

2.3 Software Requirement

The software requirements of the WSN/DTN Gateway are described below:

1. Bottom-ware Software

• Embedded OS

In this WSN/DTN Gateway, we use Voyage OS, which is light version of Debian linux OS distribution

that is best run on the embedded platforms [10].

• DTN software bundles

The DTN plays main role in this system, which is protocol in computer network architecture that

addresses the technical issues in network with lack continuous connectivity [11]. The DTN version that is

configured into this WSN/DTN Gateway system is DTN2. To implement DTN2 on top of Voyage OS, we


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need to meet several packages dependencies, and also install another 2 services, which are:

a. Oasys, which is come with DTN2 software bundle

b. Oracle Berkeley DB, which is light embeddable storage engine that provides local database [12].

2. Middle-ware Software

• DNS server

The DNS server need to be configured into the WSN/DTN system, so the user can access the

WSN/DTN Web-page Admin website, which is the part of upper-ware platform. In this implementation we

use DNSMAQ, which is lightweight version of DNS forwarder [13].

• DHCP server

The DHCP server is needed to provide dynamic IP address for the user connected to the WSN/DTN

Gateway trough WiFi Access Point, both the Bytewalla user and the WSN/DTN Web-page admin user. In this

implementation we also use DNSMAQ, which also serve lightweight version of DHCP server [13].

• Database server

The database server is mainly used to store the wireless sensor data comes from the SPOT motes, as well

as record the current setting of the WSN/DTN Gateway, either as Receiver (City) or Sender (Village). To

implement that, we used MySQL, which is an Open source Relational database management system (RDBMS)

[14].

• HTTP server

The HTTP server is to deliver WSN/DTN Gateway web-based content. In this WSN/DTN Gateway

system, we used Apache, which is an open source lightweight HTTP Server [15].

• PHP

PHP is Hypertext Preprocessor and Server-side HTML embedded scripting language, used to develop

WSN/DTN Gateway web-based UI for management and configuration [16].

• Java JDK

The WSN applications in this WSN/DTN Gateway system (Spot application, Core-Engine Sender &

Receiver) work based on java, thus we have to use JDK both to develop, debug and deployed the code to the

Spot mote and WSN/DTN Gateway itself [17].

• Ant

The Core-Engine and spot application need to be deployed and run in the WSN/DTN Gateway machine,

thus we have to use Ant, which is java library and command-line tool to build Java application [18].


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• Hald service

Hardware Abstraction Layer Daemon (HALD) is a daemon that maintains a database of the devices

connected to the system in real-time [19]. The daemon connects to the D-Bus system message bus to provide

an API that applications can use to discover, monitor and invoke operations on devices.

• SunSPOT Squawk JVM & Manager

The WSN platform that is used in this system is SunSPOT [20]. Thus, we need the to install SunSPOT

Manager that provide Squawk JVM to run application for SunSPOT Base Station.

3. Upper-ware platform (WSN/DTN Gateway platform):

The WSN/DTN Gateway system is built by different applications work together, each of it has specific

role that serve the complete service of a WSN/DTN Gateway. Below is the description of each of it:

• Spot Engine Application

The WSN Spot Engine application runs in the SPOT Mote(s). It periodically samples the built-in light,

and temperature sensor and it’s battery status, and then broadcasts these values over the radio.

• Core-Engine Sender Application

The WSN/DTN Sender Engine application runs in the WSN/DTN Gateway on the remote area

(Village). It listens for sensor-sample broadcasts trough the SPOT Base station, save received values to its

database. The WSN/DTN Gateway that run WSN/DTN Sender Engine has DTN2 service running in the

background, so it able to make this sensor data file as a DTN bundle, ready to be forwarded if there is any

DTN node connected to it that contain the route to the WSN/DTN Gateway Receiver workstation (for

example, Android running Bytewalla) [1, 2, 3].

• Core-Engine Receiver Application

The WSN/DTN Sender Engine application runs in the WSN/DTN Gateway on the city area. As same as

WSN/DTN Gateway workstation that run WSN/DTN Gateway Sender Engine, the WSN/DTN Gateway

workstation that run WSN/DTN Gateway Receiver Engine also has its own DTN2 service running in the

background, so it able to listens for any DTN bundle from any WSN/DTN Gateway Sender(s), that is sent by

any DTN node (for example, Android running Bytewalla), then save received values to its database

• Web-based Admin Application

The WSN/DTN Webpage Admin runs in the WSN/DTN Gateway either in the remote or city area. It is

designed to serve as Graphical User Interface (GUI) application to the user to control the WSN/DTN Sender

Engine or WSN/DTN Receiver Engine [3]. Through this Webpage Admin, User can set the mode of the

WSN/DTN Gateway workstation, either it will run as Sender or Receiver. Along from that control feature, this


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Webpage Admin also make User able to access the current sensor data that the WSN/DTN Gateway

workstation has in its the MySQL Database, either view it as table view, analyze it with graphic view, download

or distribute it.


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3. Software Design In the section below, we describe the design of the WSN/DTN Upper-ware platforms that will be

implemented into the system, including their feature and class diagram.

3.1. Spot Application

Below are the designed features of this application:

a. Sensing functionalities

This module handles the data collection including the temperature, humidity, battery status and time when

the data is gathered. It senses the data every 1 s and goes into sleep state.

b. Data distribution functionalities

This module handles the data broadcast operation to any Base station within the range of the Mote itself.

3.2. WSN/DTN Core-Engine Sender


a. Basic functionalities

• DTN Daemon control module

This module handles the operation to run and stop the DTN daemon from the application

• WSN Daemon control module

This module handles the socket connection to the connected Base station, read the sensor data

broadcasted by the Mote(s).

• Instruction aware module

This module handles the respond for instruction set by user trough WSN/DTN Web base GUI, which

are: the specification of WSN/DTN Gateway (DTN node name, DTN receiver name) and Start / Stop

the service (DTN sending & WSN data receiving from the mote) based on that instruction.

b. Data logging functionalities:

• Data receiving module

This module handles the operation to receive the data from the Spot Mote

• Data injection module

This module handles the data injection to the database of the WSN/DTN Gateway


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c. Data distribution functionalities:

• Data compression module

This module handles the compression operation to the file contain WSN data before it is sent as DTN

Bundle, using simple tar.gz data compression

• Scheduler distribution module

This module triggers scheduler distributions of DTN send; using dtncp command, in every specific span

time, in this simulation it is set statically every 1 minute. This module checks if there is any new data in the

database that is not distributed yet and trigger compression module before send it as DTN bundle

• Controlled distribution module

This module response to the controlled distribution instruction from user, which is set trough

WSN/DTN Web base Admin GUI. This module checks if there is any new file created by Web base GUI

that is not distributed yet and trigger compression module before send it as DTN bundle


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The classses diagram of the WSN/DTN Core-Engine sender is illustrated in the figure below:

Figure 2. WSN/DTN Core-Engine Sender Class Diagram


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3.3. WSN/DTN Core-Engine Receiver


a. Basic functionalities:

• DTN Daemon control module

This module handles the operation to run and stop the DTN daemon from the application

• Instruction aware module

This module handles the respond for instruction set by user trough WSN/DTN Web base GUI, which

are: the specification of WSN/DTN Gateway (DTN node name) and Start / Stop the service (DTN

sending & WSN data receiving from the mote) based on that instruction.

b. Data distribution functionalities:

• Scheduler distribution module

This module triggers scheduler receiving of DTN receives; using dtncpd command, in every specific span

time. In this implementation it is set statically every 1-second. This module checks if there is any new file

received from other DTN node

• Un-compression module

This module handles the un-compression operation to the file received from DTN contain WSN data

c. Data logging functionalities:

• DTN File reading module

This module handles the file checking operation, whether any file received from DTN bundle received

operation, that contain the WSN data from other WSN/DTN Gateway

• Data redundancy checking module

This module checks if the data in the file received as DTN bundle is already in the WSN/DTN Gateway

database or not

• Database data injection module

This module inject the WSN data to in the WSN/DTN Gateway database


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The classses diagram of the WSN/DTN Core-Engine Receiver is illustrated in the figure below:

Figure 3. WSN/DTN Core-Engine Receiver Class Diagram


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3.4. WSN/DTN Web-based Admin


a. Management functionalities:

• Gateway mode module

This module enable user to set the name and mode of the gateway, either as Village (Sender) or City

(Receiver), the intended receiver of the WSN data (if the Gateway running as Sender / Village).

• Core-Engine control module

This module enable user to control the core-engine, either to operate WSN data receiving from the SPOT

motes and DTN data sending / receiving or not.

• DTN Configuration control module

This module responsible to generate new DTN configuration file based on the input of the user ans used

the gateway name as new DTN EID name, and put the receiver gateway name in the route section in the

configuration to be used in proPHET routing.

b. Monitoring functionality:

This module enable user to see the detail of the running Core-Engine, either it is as Village (Sender) or

City (Receiver), and the detail about the DTN bundle (transferred, pending, received, etc)

c. Data processing & analyzing functionalities:

• Data display module

This module enable user to see the WSN data in the table, organized based on Gateway ID and spot ID

• Graphic module

This module enable user to generate the graphs (temperature, humidity, battery level) form specific spot,

during specific range time, in specific gateway (if the gateway running as receiver, it possible to receive

data from couple gateways)

• Data download module

This module enable user to download the sensing data form specific spot, range time, and gateway

d. Data distribution functionalities:

This module enable user trigger the DTN distribution operation of specific data (specific spot, during

specific time range)


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4. References [1] “WSN/DTN Gateway: Design of an embedded system interfacing a Wireless Sensor Network to the

world via a Delay Tolerant Network” https://www.tslab.ssvl.kth.se/thesis/node/1381

[2] Marco ZENNARO, Hervé NTAREME and Antoine BAGULA. “On the design of a flexible gateway

for Wireless Sensor Networks”. http://m4d.humanit.org/2008/images/stories/pdf/papers/a17-

zennaro.pdf Last visited - September, 2011

[3] “Condroid Project Plan”

http://csd.xen.ssvl.kth.se/csdlive/sites/default/files/projects/ConDroid%20Project%20Team%20V.1.

7.pdf Last visited - October 2011

[4] “Bytewalla 1: Implementation of Delay Tolerant Networks on the Android platform”.

http://www.tslab.ssvl.kth.se/csd/projects/092106/ Last visited – October 2011.

[5] “Security in Delay Tolerant Networks (DTN) for Android Platform - Bytewalla II”,

http://www.tslab.ssvl.kth.se/csd/projects/1011248/ Last visited – October 2011.

[6] “Bytewalla 3”, http://www.tslab.ssvl.kth.se/csd/projects/1031352 Last visited - October, 2011

[7] “Bytewalla 4: Implementation of Delay Tolerant Networks on the Android platform”.

https://www.tslab.ssvl.kth.se/thesis/node/1382 Last visited - October 2011

[8] “ALIX System Board” http://pcengines.ch/alix.htm Last visited - October 2011

[9] “SunSPOT world” http://www.sunspotworld.com/docs/index.html Last visited - October 2011

[10] VoyageOS http://linux.voyage.hk/ Last visited - October 2011

[11] DTN2 http://www.dtnrg.org/docs/code/DTN2/doc/manual/intro.html Last visited - October 2011

[12] Oracle Berkeley DB http://www.oracle.com/technetwork/database/berkeleydb/overview/index.html

Last visited - October 2011

[13] DNSMASQ http://thekelleys.org.uk/dnsmasq/doc.html Last visited - October 2011

[14] MySQL http://www.mysql.com/products/ Last visited - October 2011

[15] Apache http://httpd.apache.org/ Last visited - October 2011

[16] PHP http://www.php.net/ Last visited - October 2011

[17] “Java development kit (JDK)” http://www.oracle.com/technetwork/java/javase/overview/index.html

Last visited - October 2011.

[18] Apache Ant http://ant.apache.org/ Last visited - October 2011

[19] Hald(8) – Linux Man Page http://linux.die.net/man/8/hald Last visited: September, 2011

[20] SunSPOT SDK http://www.sunspotworld.com/index.html Last visited - October 2011

Condroid WSN/DTN Gateway - System Architecture & Requirement

Technology

system requirement

design of system architecture

wsn gateway

system architectureone

software requirement

performance ofwsndtn

sensor data

hardware requirement