Abstract Mobile computing has been undergoing with infrared ports to allow communication a bit of a renaissance lately. A few years ago with laptops. Then cell phones started to it was a simple matter of finding a data- come with modems built in. The connecting compatible mobile phone, a PC card methods of mobile computing, its modem, and a matching cable and installing introduction, connection types, factors it as a modem. Then people started to use affecting connections, mobile applications PDA’s as well. Cell phones started to come and its limitations are explained. Distinction between "wireless" and "mobile." Mobile Devices Introduction What is mobile computing? Challenges in mobile A view on portable devices. computing Merits and Demerits Applications Conclusion computing. Mobile computing helps users Bibliography to be productive immediately by reducing the training requirements associated with traditional automated data collection methods and provides a higher level of Introduction portability than keyboard-based systems. Field-based users can access any Wireless networking technology has information available from the system at any engendered a new era of computing, called time to make critical business decisions. mobile computing. Mobile Computing is an This information is available at the point of umbrella term used to describe technologies use, wherever and whenever they need it. that enable people to access network Portable devices like laptop and palm top services any place, anytime, and anywhere. computers give mobile users access to Ubiquitous computing and nomadic diverse sources of global information computing are synonymous with mobile anywhere and at any time. for mobile computing has prompted numerous hardware and software companies to focus their efforts in providing solutions to the vertical, form- oriented marketplace. Distinction between "wireless" and "mobile." Wireless refers to the method of transferring information between computing devices, such as a personal data assistant (PDA), and One of the most important and highly publicized a data source, such as an agency database server, recent developments in the PC world has been the without a physical connection. Not all wireless introduction of the pen interface. By using a stylus communications technologies are mobile. For to replace the keyboard, mobile computers are example, lasers are used in wireless data transfer turning thousands of computer illiterate people between buildings, but especially those involved with field-based data cannot be used in mobile collection into computer users. The market potential and breadth of application requirements communications at this time. Here we have seven different types of mobile Mobile simply describes a computing device that devices: is not restricted to a desktop. A mobile device may Laptop computers be a PDA, a "smart" cell phone or Web phone, a PDA’s and handheld PCs laptop computer, or any one of numerous other Pagers devices that allow the user to complete computing Smart phones and cellular phones tasks without being tethered, or connected, to a Task devices, such as bar code scanners network. Mobile computing does not necessarily Blue tooth require wireless communication. In fact, it may not Bridge require communication between devices at all. Mobile devices Laptops are typically used and supported in the have intense and constant need for time sensitive same way as desktop PCs. In fact, many communications. organizations have replaced desktops with their Pagers that support one- and two-way text portable cousins, as the workforce has grown messaging are also used in similar situations. increasingly mobile. Third party vendors most often provide support for PDA’s, however, are the least planned for and these devices. supported devices. They are undergoing rapid Task devices such as the parcel tracking evolution and are being brought into organizations devices used by Federal Express (FedEx) and the in the same way the earliest PCs were. That is, United Parcel Service (UPS) delivery personnel adventurous early adopters buy the devices for are most often bought as part of a complete system their personal use and then ask IT departments to from a third-party vendor. Because they are integrate the devices into the corporate IT frequently mission-critical, most corporations environment. support task devices as rigorously as desktop Smart phones that allow users to access phone computers. calls, two-way radio transmissions, and paging and Bluetooth:- A short-range wireless standard that data transmissions on one device are also finding specifies radio connections between devices within applications in hospitals and other situations that a 10-meter range of each other. Bluetooth is designed as a Personal Area Network (PAN, or WPAN for "Wireless Personal Area Network") device weight, battery power, screen size, technology with a wide variety of theoretical uses. portability, quality of radio transmission, error Bridge:- A device that connects two local-area rates. Mobility brings additional uncertainties, as networks (LANs), or two segments of the same well as opportunities to provide new services and LAN. Bridges simply forward packets from one supplementary information to users in the segment to another without analyzing or routing locations where they find themselves. messages. This allows them to connect dissimilar The major challenges in mobile computing are networks (e.g., a bridge can connect an Ethernet described including: low bandwidth, high error and Token-Ring network). rate, power restrictions, security, limited Challenges in mobile computing capabilities, disconnection and problems due to Wireless and mobile environments bring different client mobility. challenges to users and service providers when compared to fixed, wired networks. Physical constraints become much more important, such as Low Bandwidth network connections. The wireless Wireless networks deliver lower bandwidth environment exhibits higher error rates, than wired networks. As a result, mobile which results in retransmission and affects applications have to be carefully designed to the Quality of Service. By minimizing the control the bandwidth consumption. usage of wireless transmission, the data is Software techniques required to improve less exposed to transmission errors. In effective bandwidth usage include data addition, error correction schemes can be compression logging requests to combine employed to improve performance. multiple short ones, lazy write back, However, these schemes also add to the difference-based updates, caching, communication overhead and reduce the prefetching, usage of proxy, priority usable bandwidth. scheduling, etc. Power Limitations Mobile computers are concerned with the High Error Rate limited power supply, an issue that does not The network quality varies as the mobile appear in distributed wired environment. computer moves across the heterogeneous Hardware improvements on batteries can help to lengthen the life of a charge and Security reduce battery weight. In addition, efficient Security and privacy are of specific concerns software operations can help to lower the in wireless communication because of the power consumption. Examples include: ease of connecting to the wireless link shifting the processing to a fixed host, anonymously. Common problems are aggressively caching and prefetching data to impersonation, denial of service and reduce disk traffic, and transmitting less data tapping. The main technique used is while receiving more encryption. In personal profiles of users are used to restrict access to the mobile units. Merits Improving information flow Allowing faster adaptation to changing The benefits of automating data collection business conditions applications with mobile computing are the Increasing responsiveness and customer reduction of hard and soft costs, satisfaction enhancement of revenue potential, and a Providing access to previously distinct competitive advantage through: unavailable information Improving the data collection process Improving data accuracy Demerits Reducing paperwork The demerits of the mobile computing are Enforcing collection of more complete discussed as follows: information Facilitating collection of more useful Information access via a mobile device information is plagued by low available bandwidth, Eliminating redundant data entry poor connection maintenance, poor Reducing administrative costs security, and addressing problems. Reducing billing errors Unlike their wired counterparts, design Reducing data backlog of software for mobile devices must themselves. In general, most application consider resource limitation, battery software, operating systems, and power and display size. Consequently, network infrastructures are intended for new hardware and software techniques more conventional environments, and so must be developed. For example, the mobile, wireless user has great applications need to be highly optimized difficulty exploiting the computational for space, in order to fit in the limited infrastructure as fully as he or she might. memory on the mobile devices. There is an emerging consensus among Mobility brings additional uncertainties, researchers that a new architecture and as well as opportunities to provide new dynamic infrastructure is an appropriate services and supplementary information way to address this problem. to users in the locations where they find Day by day as the standard of the mobile Vertical industries where mobile technology has computing is increasing the boons of mobile already been successfully adopted include computing are changing to banes. Eg: The most Consumer Goods, Delivery and Route Sales, deadly terrorist attack occurred on sept 11, 2001. Government, Healthcare, Market Research, Pharmaceuticals, Transportation, and Utilities. Applications New technical and application Consumer Goods. Typical applications include developments have established that mobile inventory, merchandising, order entry, and sales systems can be a cost-effective, efficient, automation. Features found in these applications and productive solution in several different usually provide access to stock and pricing types of application environments. They information, monitor promotions, and perform are:- a new generation of satellites, shelf space analysis including number of facings especially Low-Earth Orbit systems and product age. Customer detail helps reps to act (LEOS) are under development with the more as consultants than order takers. Internet in mind. Companies like Teledesic and Orbcomm are actively promoting Delivery & Route Sales. With fierce competition Internet access. and an increasing inventory, having timely and accurate information is more important than ever. Government. Applications center around Market Research. Automating the survey process assessments, inspections, and work orders. Most of has enabled these companies to get their data more these applications involve auditing some sort of accurately and quickly while being able to facility or process (food service, restaurant, customize their queries at will. nursing home, child care, schools, commercial and Pharmaceuticals. In addition to the reps need to residential buildings). perform account management and call reporting functions, the FDA’s requirement for physician Healthcare. The focus in this industry has been on signatures for all drug samples dispensed was an automating patient records, medication dispension, added complication that was eliminated through and sample collection. A common goal is to the use of mobile technology. leverage mobile computing in the implementation of positive patient identification. Transportation. Transforming freight to perform inspections on a routine basis. damage inspections from paper to mobile computing greatly expedites the process and Conclusion reduces costs by providing on-line pre- Mobile computing is rapidly becoming shipment inspections. This technology also popular, and user demand for useful wireless offers a more efficient means of storing and applications is increasing. transmitting maintenance inspection reports. Additionally, this paper shows how these In conjunction with GPS (global positioning behavioral extensions serve as a powerful systems), mobile computing allows abstraction for practical systems. companies to provide better customer In this paper, we have looked at issues service by being continually aware of related to portable devices, merits, demerits exactly where any given shipment is when and applications in mobile environment. in transit. Because of the banes of mobile computing the security level should be improved. Utilities. Eliminating the rekeying of data and providing a means to perform on site analysis are instrumental to an industry that is required Application design for wireless computing : M-Mail: A Case Study of Dynamic Application Partitioning in Mobile Computing Christine Julien and Gruia-Catalin Roman : Bibilography Active Coordination in Ad Hoc Networks Raymond J. Brunsting : Quality of Service Terri Watson. : Application design for Issues in Wireless Networks wireless computing.