Delivering content to mobile devices

Written by: Jonathan Briggs

March 17, 2006 [2885 views]

In this week's lecture we will continue to look at how we can deliver content based services to mobile devices. This will include a discussion of WAP and xHTML.

Consider

• Usability
• Push versus pull
• Secure
• Images
• Text
• Rich content (audio, video, Flash, games)
• Personalised
• Based on location
• Interaction
• Payment

Design constraints (adapted from Nokia technical documentation)

• Different phones have different technical characteristics (size, colour, speed, data connectons, functionality)
• Smaller screens in a variety of sizes
• Limited colour resolution on some displays
• Text input is more awkward than on a PC
• No familiar pointing devices
• Limited browser functionality (scrolling may be vertical only)
• Data speeds are slower than many Internet connections
• Storage of data on the mobile device (cookies for example) may be limited
• Data transfer will be charged

Coding content for mobile (special language versus xHTML?)

WAP 1.0

• Developed for Europe & US
• Special protocol for mobile content using its own language WML
• Special formats for images
• Wireless scripting language
• Web pages became stacks of cards
• Content was passed through a gateway to make it smaller
• Compatible with most phones (at the time)
• Hard to write
• Content had to be developed especially for WAP 1.0

An example WAP 1.0 site written in WML can be found here

Compact HTML

• Developed for iMode in Japan
• Much more similar to HTML
• Easier for developers

Brief introduction to iMode

WAP 2.0 (xHTML Mobile profile)

• Now becoming standard
• Based to xHTML (strict subset of HTML)
• CSS used to style the content specifically for mobiles
• Allows ordinary web content to be served to mobile users
• Served from http servers without the need for a gateway.

Design considerations

• Order of loading and displaying page components
• Reduce unnecessary scrolling
• Navigation
• Consider using access keys (linking phone keys to menu items)
• Images
• Data input
• Avoid pop-ups, frames and rich media unless you know the target device supports them

Push (alerts, broadcasts, subscriptions)

• SMS with a link that automatically loads the page
• J2ME Applet is an alternative

Security

• Standard considerations such as SSL (security certificates, to authenticate the source of the content)

Personalising the content based on location or user

• Personalisation will be at the server
• User identity is passed in the request header
• Handset characteristics can also be obtained
• Web services could be used to find out billing, location or subscriber info

How do you pay for content?

• Data charges
• Online subscription
• Application download
• Operator portal relationship

Putting it all together

Suppose we wanted to develop mobile cookery content

• Mobile version of xHTML pages
• Designed from a usability perspective to be viewed on the small screen
• Perhaps single image of typical screen size
• Simple navigation (ingredients, method, next, home)
• Recipe of the week notified by WAP Push
• Subscription set up via web site or operator portal
• Hosted and served from web server
• Subscribers authenticated by server and non-subscribers redirected to intro information
• Hard to market
• Not particularly compelling content for mobile
• Needs to be linked to ‘in store’ shopping experience?
• Likely to be a disappointing business

Useful links

Mobile Content News
Fast and easy xHTML and CSS
Creating Web Content for Mobile Phone Browser
Download a phone emulator

 

  

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