In the seven years that Daniel Freeman, the chapter's author, has been involved with mobile media, he has witnessed many ups and downs. "One of the high points has been seeing the mobile phone application environment finally prove itself in the deployment of compelling applications, such as push e-mail and mobile TV services that look and feel like TV," he says.  "The low point has been the dumbing down of content services in the WAP environment because of the massive divergence of phone capabilities."

Freeman, who has been working in the areas of music, mobile TV and gaming, intends for this chapter to provide useful and practical tips on application development and content creation both from a planning and an implementation perspective, in order to highlight the importance of design aspects such as ease of use, reliability and the ability to reach as wide a user base as possible.

Chapter summary
Chapter four, Designing Services, provides a number of guidelines to help ensure that business stakeholders make educated choices and project managers set appropriate requirements at an early stage to make sure services are successful from launch.

The chapter opens by stressing the importance of thinking carefully about the required features of a service and its overall nature from the very beginning of the conceptual design phase, and presents a set of service classifications that can be useful in understanding the main considerations involved in creating a new service.

Application functionality can be broken down into five areas:

• Server-side applications   
• Streaming media applications   
• Browser-based applications   
• Device-only applications   
• Network-enabled applications.

Each of these categories is examined in detail, with case studies of successful applications in each from the likes of Yahoo. Also addressed are the realities of creating applications that need to work across a wide range of devices with varying capabilities, constantly changing network conditions, and operator-imposed access restrictions.

The next section of the chapter presents the key factors of successful mobile applications, primarily from a user-experience perspective.

The first, easy access, is perhaps the most important factor to consider with regards to usability. If a service is not easily available, it will not be used. The foundations of easy access are instant gratification, personalization and the understanding that no matter what the application does, it is still used on a mobile phone.

Next, a set of design principles that support the philosophy of easy access are presented. For the most part, these are the standard, sound principles of good usability, but applied to the unique properties of the mobile world. Applications need to be easy to launch, require minimal data input on the part of the user, be easy and fast to use, take into consideration the restricted user interface of the mobile device, and always let the user know what is going on.

The next factor is obvious, but overlooked surprisingly often. Applications are used on mobile devices connected to wireless networks. Users will be connecting from widely-variable network conditions – ranging from narrowband GSM to broadband WCDMA – sometimes moving from one network to another in the middle of a session. Additionally, roaming between operators? networks can have a significant impact on a service's availability and cost.

All these elements are addressed in the section on wireless design considerations. Issues such as throughput, latency and quality of service need to be taken into consideration when creating a service or application.

The final part of the chapter covers the creation of mobile media content, looking at the factors that come into play when delivering images, audio and video over a wireless network to a mobile phone. The nature of codecs used, delivery systems, and display capabilities of devices have to be considered when creating appropriate mobile content. It takes more than just re-broadcasting a TV program to a mobile phone to achieve success.

In the end, Freeman's advice to developers is: "Avoid over-complicating your application.  Listen to what the consumers' needs are and focus on that."

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By John Maxwell Hobbs