Download Technical Introduction to Wireless Application Development

Technical Introduction to
Wireless Application
Development
Developing applications in the top three
wireless environments
Dave Evartt ~ Systems Architect
United States Army Medical Research and Materiel Command
Telemedicine and Advanced Technology Research Center
Email: [email protected]
Wireless is easier than you think!
 It’s been around forever
– Amtor, Pactor, RTTY, FAX, NASA’s Deep
Space Network, Amateur Radio (packet radio).
 Easy to do, any programmer can do it.
 Convergent future can eliminate
distinctions.
Most wireless applications use:
 WAP (Wireless Application Protocol)
 Web Clipping (Palm VII and similar
devices)
 TCP/IP over RF - includes
– 802.11(a,b,e), HomeRF, X25a,
802.15(Bluetooth), other x25 derivatives
– Proprietary
WAP
 Pros:
– Handy for VERY limited use devices, most
commonly cell phones
 Cons:
– Not enough:
• Page size (limited to 1500 bytes)
• Low bandwidth
– No future
• Overcome by technology changes
– No standard implementations
– Not practical for most uses
Developing WAP Applications
 HTML like - Uses deck of cards paradigm. Only
presents one ‘card at a time’ on screen.
 //content type="text/vnd.wap.wml"
 <?xml version="1.0"?>
 <!DOCTYPE wml PUBLIC "-//WAPFORUM//DTD WML 1.1//EN"








"http://www.wapforum.org/DTD/wml.xml">
<wml><card id=“menupage”><p>
Greetings from ATA 2001 – Please choose between the following:
<do type="options" label="New">
<go href="#NewPage"/></do>
<do type="options" label="top">
<go href=“index.html"/></do>
</p></card>
</wml>
Example: http://wehali.com/tsalagi/tsalagi_wml.cfm
Web Clipping
 Pros:
– Screen size within acceptable limits
– Server Based
– Forms and images can be stored on the device
 Cons:
– Limited Use, Only a couple of devices
available.
– Slow, even with the new systems
– No scripting
Developing Web Clipping
Applications
 Major differences are:
– Uses subset of HTML 3.2 (most tags are implemented)
– Screen size – Limited to 160 x 160 pixels
– Forms can be stored on device, no need to download.
– One Metatag
• <meta name="palmcomputingplatform" content="true">
– Images
• Black and white (two tone)
– Can invoke Palm applications
• <a href="palm:PPDT.appl?http://server.com/URL">
TCP/IP over RF
 No differences to programmer
 Becoming faster and faster
 Increasing security
 Range is limited by hardware
– Global with satellite
Bluetooth
 Pros:
– Can virtually eliminate cables.
– Ad hoc networking
– Several range choices: 1m, 10m, 100m
– Simple API calls. Can be as simple as ‘normal’
network programming.
– Industry expects 900 million devices by 2005
 Cons:
– Not here yet. Some devices just starting to trickle into
the market.
– Still too expensive – Goal is $5 per unit in quantity
Conclusions
 Wireless is here to stay
 Easy to implement
 Bandwidth, display, functionality will drive
convergence to non-device specific
applications.