Wireless Devices & Location Smart Databases

A number of international organizations are active in the field of location based mobile services, in particular, the OpenGIS Consortium [OGC], the World Wide Web Consortium [W3C] and the Wireless Application Programming Forum [WAP]:

The OGC manages consensus processes that result in interoperability among diverse geo-processing systems. To paraphrase the consortium’s own words: “Much geospatial data is available on the web and in off-line archives, but it is complex, heterogeneous, and incompatible. Users must possess considerable expertise and special geographic information system (GIS) software to overlay or otherwise combine different map layers of the same geographic region. Data conversion is cumbersome and time-consuming, and the results are often unsatisfactory. Common interfaces are the only way to enable overlays and combinations of complex and essentially different kinds of geographic information to happen automatically over the Internet, despite differences in the underlying GIS software system. OGC brings together key players and provides a formal structure for achieving consensus on the common interfaces.”
The W3C is dedicated to leading and advancing the development of the World- Wide-Web.
The WAP Forum is dedicated to enabling advanced services and applications on mobile wireless devices, such as cellular phones, pagers, personal digital assistants and other wireless terminals.

In 1997 there was an upsurge of interest amongst W3C members for access to the web via mobile and wireless devices. In 1998 the mobile access interest group was formed in the W3C. This group is chartered with the investigation of the impact of mobile access on the specifications and recommendations of the W3C.

The objectives of the WAP Forum are:

To bring Internet content and advanced data services to digital cellular phones and other wireless terminals.
To create a global wireless protocol specification that will work across different wireless network technologies.
To enable the creation of content and applications that scale across a very wide range of wireless networks and wireless device types.
To embrace and extend existing standards and technology wherever appropriate.

Both W3C and the WAP Forum are working together to achieve the following:

Bring Internet and WWW technologies to digital cellular phones and other wireless terminals by adapting the Web architecture to the wireless environment.
Establish productive working relationships between the W3C and WAP Forum in the areas where common organizational goals exist.
Reduce overlapping technical work between the W3C and WAP Forum.
Cross reference technical specifications and perform joint test-bed and protocol validation work.
Work toward a unified information space and toward common standards and technologies.
Enable the delivery of sophisticated information and services to mobile wireless terminals.

Technical Problems
Providing Internet services on a wireless data network presents many challenges. Most of the technology developed for the Internet has been designed for the desktop and larger computers supporting medium to high bandwidth connectivity over generally reliable data networks. Similarly, wireless data networks present a more constrained communication environment compared to wired networks, because of fundamental limitations of power, available frequency spectrum, and mobility.

Several fundamental constraints place restrictions on the type of protocols and applications offered over the network. They are:

Power consumption – as bandwidth increases, power consumption increases and in a mobile device this reduces battery life.
Cellular network economies – mobile networks are typically based on a cellular architecture. Cells are a resource shared by all mobile terminals in a geographic area, and typically have a fixed amount of bandwidth to be shared amongst all users. This characteristic rewards efficient use of bandwidth, as a means of reducing the overall cost of the network infrastructure.
Latency – the mobile wireless environment is characterized by a very wide range of network latency, ranging from sub-second round trip times to many tens of seconds.
Bandwidth – the mobile wireless environment typically has far less bandwidth available than in a wireline environment.

Wireless devices operate under a set of physical limitations imposed by their mobility and form factor, including:

Limited power – mobile devices have a very limited power reserve due to existing battery technology. This reduces the available computational resources, bandwidth, etc.
Size – many mobile devices are very small.

Mobile wireless devices are also characterized by a different set of user interface constraints than are personal computers. To enable a consistent application-programming model a very wide range of content scalability is required. In practice, a significant amount of the current WWW content is unsuitable for use on a hand-held wireless device. Reasons for this include:

Output scalability – existing content is designed for viewing on PC screens, whereas mobile devices will have a wide range of visual display sizes, formatting and other characteristics.
Input scalability – mobile devices feature a wide range of input models, such as numeric keypads and very few or no programmable soft keys.

Many wireless devices are consumer devices, used in a wide variety of environments and under a wide range of scenarios, for example:

Simple user interface – consumer devices demand that their user interfaces be extremely simple and easy to use.
Single purpose – the goal and purpose of most mobile devices is very focused, which is in contrast with the general-purpose nature of the PC. This motivates a very specific set of use cases, with very simple and focused behavior.
Hands-free, heads-up operation – many mobile devices are used in the environment where their use should not be necessarily distracting (driving a car for example).

WWW Developments
The next generation of web technologies is intended to enhance the users’ and publishers’ control over the presentation of the information (Cascading Style Sheets, CSS), the management of the information (Resource Description Format, RDF) and its distribution (Platform for Privacy Preferences, P3P). Furthermore, they are based on technologies that structure and distribute data as objects (XML and HTTP-NG), and include the following future developments:

XML and HTTP – The W3C has recently decided to initiate an activity to create a new generation of HTML. This will be based on XML and is likely to include features that make it more efficient for mobile use.
XML and SVG – The W3C is working on a specification for a Scalable Vector Graphics (SVG) format, again based on XML. The SVG will be implemented in browsers and authoring tools and should be the natural replacement for many of the current uses of raster graphics. Adoption of SVG should mean that the graphics in web documents will be smaller, faster, more interactive, and be displayable on a wider range of device resolutions from small mobile devices through to high resolution monitors and printers.
WML – Wireless Markup language (WML) is based upon XML and is intended for use in specifying content and user interface for narrowband devices, including cellular phones and pagers. WML has been designed with the limitations in mind of the wireless devices that we have already talked about.
NVML – Navigation Markup Language is a markup language, defined using XML, for describing navigation information such as locations of points and route information, which enables the use of a navigation service not only in cars but also on other transportation systems using mobile devices ranging from handheld PCs to cellular phones.
GML – Geography Markup Language is an XML encoding, being developed by the OpenGIS Consortium, for the transport and storage of geographic information, including both the spatial and non-spatial properties of geographic features. It is anticipated that GML will make a significant impact on the ability of organizations to share geographic information with one another, and to enable linked geographic datasets. GML encoding is intended to support both data storage and data transport. Implementors may decide to store geographic information in GML, or they may decide to convert from some other storage format on demand and use GML only for data transport.