Mobile Computing Mobile Voice Communication
“MOBILE COMPUTING” means computing done by intermittently-connected users who access network resources. It requires a wireless medium such as cellular radio, radio nets and low-orbit satellites. It incorporates wireless adapters using cellular telephone technology to connect portable computers with the cabled network.Mobile voice communication is widely established throughout the world and has had a very rapid increase in the number of subscribers to the various cellular networks over the last few years. An extension of this technology is the ability to send and receive data across these cellular networks. This is the principle of mobile computing.
Mobile data communication has become a very important and rapidly evolving technology as it allows users to transmit data from remote locations to other remote or fixed locations. This proves to be the solution to the biggest problem of business people on the move-mobility.
Our mobile system architecture supports applications by a middleware stub. Mobile Computing evolved during the last few years as a result of shrinking portables and growing wireless networks. It enlarges the usability of computers, but raises demanding challenges.
INTRODUCTION
The architecture consists of a Mobility Service Architecture, describing the way we implement our mobility services in a computer system, and a Mobility Environment Architecture describing how data are transmitted between computers in mobile environments and what tasks the different stations fulfill in our architecture
Mobility Services Architecture:
Mobility services can be classified into three groups. First there are services designed to overcome common restrictions of mobile computing, which arise mainly from the slowness, insecurity and instability of wireless or analogous connection lines utilized by the mobile user. These services are called common mobility services (CMS). Examples are connection management, caching or encryption services. The second group of services handles the management and administration of mobile users moving around and connecting their portables to networks at different places. These mobility management services (MMS) include tasks such as the authentication of users, accounting and billing
issues or profiling of the users' habits. The tasks necessary to adapt certain existing applications to mobile usage are implemented by high level services, which are called special mobility services (SMS). Special mobility services adapt existing services to the mobile conditions. For example to allow remote database access over a wireless connection line one has to take special care of possible frequent connection losses especially in the context of the state of the database. Viewing services as distinct building blocks, we are able to sketch architecture for a "mobility services enhanced system".
Mobility Environment Architecture:
To overcome restrictions in mobile computing the above architecture was designed; the architecture consists of the following parts: The network environment consists of mobile hosts fixed hosts and certain access points. The fixed hosts are all connected to a backbone (i.e. the Internet). Mobile hosts usually don't contact them directly, but use physically closer located hosts as access points to the backbone for means of minimizing the distance which has to be bridged by a mobile connection line. In addition to the users carrying a portable computer with them, also mobile users traveling between fixed hosts are considered in our system.
Problems in Wireless industry
o Handheld mobile devices could access network based content but the technologies were incompatible
o Not much use of existing internet infrastructure.
o No single global standard for data access for all handheld mobile devices.
METHODOLOGY
WAP
Wireless application protocol (WAP) is an application environment and set of communication protocols for wireless devices designed to enable to manufacturer vendor, and technology-independent access to the Internet and advanced telephony services .
WAP is designed for
Primarily included mobile phones, pagers, PDA’s.
Low bandwidth &high latency environments.
Unpredictable stability & availability.
Limited processing power & battery life.
Less memory (ROM & RAM).
Smaller displays.
WAP Applications
“At first, the most popular mobile Internet service is likely to be e-mail. SMS (short message service) messages have proved a big success in the Nordic nations and volumes are growing rapidly throughout western Europe”
One of the most significant advantages of Internet access from mobile rather that your PC is the ability to instantly identify users geographic location. This opens up a huge opportunity for highly customized services.
As Ericsson puts it, “the content providers will know where their users are geographically and will be able to direct them to specific destinations - restaurants or theaters, for example handheld devices are mobile, but their position is instantly identifiable. So think of content that knows where the user is, and offers content tailored to that geography. Weather forecasts, restaurant locations (with table availability and instant reservations fast food delivery, finding and booking a plumber, dating services (with pre-recorded video profiles and e-mail or voicemail exchanges) any service where physical proximity is important can migrate a vital part of its value-added to the new devices.”
The Problem areas One of the problem, basically to do with infrastructure (and not WAP) is that as the
mobile Internet access, thanks to WAP, increases it is likely to put ever greater demands on existing technology infrastructures as it encourages higher m-commerce volumes. A live example is I-mode services in Japan, where the mobile data access has seen a unprecedented rate of growth. So, unless the infrastructure is geared up to expect unexpected volumes, this can have significant impact on these data services since most of these systems are simply inadequate for big volumes. So there is a possibility of unsatisfactory performances observed by mobile data users.
Another problem area is that the delay in the delivery of long-promised terminals and service launches are narrowing the window of opportunity for WAP, while the proposed developments in faster mobile networks and more sophisticated terminals come closer. Further developments in WAP are still required and in the meantime, other solutions will emerge.
Also as with many other technologies what matters most and what guides the development of a technology is the emergence of “killer applications”. So, unless some killer applications hit the market, which influence the mood of the enduser, WAP just like other technologies has a difficult path ahead. Already due to lots of hype WAP proponents find them selves in a little tight position. So, this presents a big opportunity for the developer community to develop new and innovative applications that can realize the advantage of WAP. There is going to be big appetite for WAP applications in the very near future.
IMPLEMENTATION
J2ME
The Java 2 Platform, Micro Edition (J2ME) is the Java 2 platform targeted at consumer electronics and embedded devices like wireless phones, pagers, personal digital assistants, camcorders, game devices, small retail payment terminals and smart cards.
J2ME delivers the power and benefits of Java technology to consumer and embedded devices. It includes flexible user interfaces, a robust security model, a broad range of built-in network protocols, and extensive support for networked and offline applications that can be downloaded dynamically. Applications based on J2ME specifications are written once for a wide range of devices, yet exploit each device's native capabilities.
J2ME platform technology has three components which, taken together, form a compliant Java application environment:
A Configuration is a combination of a Java virtual machine and a set of application support APIs that are shared across a class of devices.
A Profile is a set of APIs (designed for a specific configuration) that address the needs of a narrower device category.
An Optional Package is a set of technology-specific APIs that extends the capabilities of a Java application environment.
A J2ME-compliant Java application environment requires both a configuration and a profile. Optional Packages provide device designers and other JCP participants with a standards-based extension framework.
DIFFERENT TYPES OF CONFIGURATIONS
CLDC:
The CLDC configuration was designed to bring the many advantages of the Java platform to connected devices that are limited in available resources. Targeted devices include cellular phones, pagers, mobile point-of-sale terminals, and any other device constrained in processing power, memory, and graphical capability.
CDC:
The Connected Device Configuration is a standards-based framework for building and delivering mobile applications that can be shared across a range of network-connected personal mobile devices. Typically, these devices include a 32-bit microprocessor/controller and require about 2 MB of RAM and 2.5 MB of ROM for the Java application environment.
DIFFERENT TYPES OF PROFILES
Foundation Profile:
Foundation Profile is a set of Java APIs that support resource-constrained devices without a standards-based GUI system. Combined with the Connected Device Configuration
(CDC), Foundation Profile provides a complete J2ME application environment for consumer products and embedded devices.
Personal Basis Profile:
J2ME Personal Basis Profile is a set of Java APIs that support resource-constrained devices with a standards-based GUI framework. Combined with the Connected Device Configuration (CDC), J2ME Personal Basis Profile provides a complete J2ME application environment for consumer products and embedded devices.
Personal Profile:
J2ME Personal Profile is a set of Java APIs that supports resource-constrained devices with a GUI toolkit based on AWT. Combined with the Connected Device Configuration (CDC), J2ME Personal Profile provides a complete J2ME application environment for consumer products and embedded devices.
