Overall Structure Introduction Use Cases Methods Results Other Outcomes Future Directions Summary
Introduction to “Serval Mesh” A software that can be installed only on the Android based Smartphones. Does not depend on any infrastructure. Creates a Mobile Ad Hoc Network (MANET), which is also called ” Serval Mesh” that allows the Smartphones to communicate with each other. Previously used only the WiFi Ad-hoc mode to communicate through the Mesh.
During a Disaster Traditional Cellular System Serval Mesh
No Cellular Communication Serval Mesh Traditional Cellular System
WiFi Multi Model Management Serval Mesh Traditional Cellular System
Use Cases Base of Pyramid Population: To support poor population Disaster and Rescue Purpose: To support any type of phone i.e., rooted or unrooted. Remote or Rural Population: To support population in areas where 1)No cellular network or 2)Marginal cellular coverage
My Research Question How can we maximise mesh connectivity among existing and new models of Android phones given the lack of Adhoc WiFi support on Android OS?
Solution to the Problem WiFi mode cycling to maintain connectivity among devices. Get most WiFi modes out of every handset especially Adhoc mode.
Challenges: Serval WiFi System Android OS does not support Adhoc Interface Use of non Scalable “Android WiFi Tether” code to set the WiFi Adhoc mode
Android WiFi Tether Not Scalable as it is a single Complex Script containing commands for all the handset models. Device Centric and not Chipset Centric. Edify Script and Detection Script
Android WiFi Tether Detection of the chipset was hard- wired into java code. Need to recompile the code during the addition of new phone Compiled java Phone Detection Script Structure of Android WiFi Tether Code
Current WiFi Manager Placing of all detection and commands into separate files per chipset type. Support for previously unsupported phones can potentially be added in the field with no internet access. The chipset of the phone is detected during the installation phase. Detection Script Edify Script WiFi Manager
Current WiFi Manager The installation may fail due to one of the below reasons The phone supports more than one chipset Chipset of the phone is not detected. This is recorded in the log files. The user can send this across to the support centre. Followed by the execution of the corresponding edify scripts (commands to set up the ad-hoc WiFi interface) to set up the ad-hoc mode. The edify scripts are created for each chipset, this way it is easy to include the script for any new Android handset introduced in the markets without even changing the structure of the code.
Analysis of Client Mode It is the default mode. Supported in the Android OS. It does not require any root access. Enables even a non rooted phone to connect to the Serval mesh.
Access Point Mode The Android version 2.2 (Froyo) allows the Smartphones to turn on the Wi-Fi hot spot. With this application the mobile phone operates in the Access Point mode and creates a WiFi hot spot that enables up to eight devices such as mobile phones, PDAs and laptop to connect to the hot spot. With the help of this application, it makes it easy to create Personal Wi-Fi hotspot without making any major changes in the code. Therefore, if the mobile has the corresponding Android version 2.2 then it can potentially support the Access Point.
Automatic Cycling of WiFi Modes The cycling of WiFi modes is developed to switch between modes (Client, Access Point, Ad-hoc, off)for every thirty seconds. The allocation of thirty seconds for each mode is implemented for experimental purpose. Currently, it gives equal opportunity to all the modes. In the future, depending on the use case the software can let the user to change the strategy.
Automatic Cycling of WiFi modes The timing of this cycling is maintained by setting an alarm. It checks if there is any peer connected to the phone for every alarm. If it is, then it will not cycle to the next potential mode. Otherwise, it will stop the current mode and start the next mode. The current mode is displayed as a label. The drop down list contains the above mentioned modes (Client, Access Point, Ad-hoc, Off) depending on whether the phone is capable of supporting that particular mode.
Results Serval mesh in AP mode Serval mesh in Client mode
Results Sample Comments from the Android Users 1“I have installed and made my first call between zte blade cm7 and T-Mobile pulse mini in less than a minute. Good work guys”. 2 “ An app worthy of praise The aims of the Serval Mesh project should be supported. Visit the project website for full info. As Android users tend to be more tech-minded, I hope people will try the app and give useful feedback to the devs. For me, I have it on a Hero and a NexusOne, communicating, sort of... :)”
Discussions The code has been successfully implemented and tested on Huawei U8150 IDEOS phone. Feedback is also coming in from various handsets, as the software has been released as a prototype to the broader developer community for testing. Although the code seems to be highly successful with the recommended phone, it is frequently unstable with other Android phones.
Future Directions The Future direction of this project will be analyzing an efficient Cycling Strategy, which will meet the end user needs. Automate the sending of the log files and other testing data, with deeper user involvement. The current WiFi Multi Modal Management system has to be revisited when new modules such as SMS, Rhizome, Video Streaming, Mapping Service of the Serval project is been added as they all work collaboratively.
Other Outcomes Have been a co-author for “Serval Mesh Software – WiFi Multi Model Management” paper submitted at “ACWR 2011, International Conference on Wireless Technologies for Humanitarian Relief”. Assisted “the Serval Project” team (www.servalproject.org) to receive a grant of $40,000 from the Dutch NLnet Foundation.
Summary The problems with the previous version of the “Serval mesh” WiFi system was analysed The solutions to those problems were addressed. The results was also discussed with suitable screenshots.
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