18-09-2014, 02:37 PM
wireless Commmication Mobile Computing
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ABSTRACT:-
Today’s fast growing world needs faster communication. Technology is making rapid progress and is making many things easier. The innovative idea’s that have been emerged from the tender minds of young scientists led to the evolution of many techniques where our present topic ‘MOBILE COMPUTING’ fits in.
“MOBILE COMPUTING” and COMMUNICATIONS is a major part of wireless communication technology. Mobile computing in 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 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
INTRODUCTION:-
The most familiar aspect of mobile computing technology is the hand phone. About two decades ago, a hand phone was bulky and was only used for voice communication. It was merely an extension of the fixed line telephony that allowed users to keep in touch with colleagues. Now the hand phone is not only used for voice communication, it is also used to send text and multimedia messages. Future mobile devices will not only enable Internet access, but will also support high-speed data services.
In addition to the hand phone, various types of mobile devices are now available, for example, personal digital assistants (PDAs) and pocket personal computers (PCs). Road warriors use mobile devices to access up-to-date information from the corporate database. A police officer at a crime scene may send a fingerprint picked up there for matching with data in a central database
Evolution of Wireless Networks and Services
The first generation (1G) wireless network was analog. The first in North America was advanced mobile phone system (AMPS), which was based on frequency division multiple access. A total of 1664 channels were available in the 824 to 849 MHz and 869 to 894 MHz band, providing 832 downlink (DL) and 832 uplink (UL) channels. AMPS, widely used in North America, supports frequency reuse. The underlying network is a cellular network where a geographical region is divided into cells. A base station (BS) at the center of the cell transmits signals to and from users within the cell.
The second generation (2G) systems onward are digital. Digital systems make possible an array of new services such as caller ID. The Global System for Mobile Communications (GSM) is a popular 2G system. GSM offers a data rate of 9.6 to 14.4 kbps. It supports international roaming, which means users may have access to wireless services even when traveling abroad. The most popular service offered by GSM is the Short Message Service (SMS), which allows
TYPES OF MOBILE COMPUTING
Mobile computing is a generic term describing one's ability to use technology while moving, as opposed to portable computers, which are only practical for use while deployed in a stationary configuration.
Many types of mobile computers have been introduced since the 1990s, including the:
• Wearable computer
• Personal digital assistant
• Smartphone
• Carputer
• Ultra-Mobile PC
Wearable computers
Wearable computers are computers that are worn on the body. This type of wearable technology has been used in behavioral modeling, health monitoring systems, information technologies and media development. Wearable computers are especially
Ultra-Mobile PC:-
between Microsoft, Intel, Samsung, and a few others. As of late 2009, there were very few devices on the market and UMPC device category was expected to go extinct soon, according to CNET.
Insufficient bandwidth
Mobile internet access is generally slower than direct cable connections, using technologies such as GPRS and EDGE, and more recently 3G networks. These networks are usually available within range of commercial cell phone towers. Higher speed wireless LANs are inexpensive, but have very limited range.
Power consumption
When a power outlet or portable generator is not available, mobile computers must rely entirely on battery power. Combined with the compact size of many mobile devices, this often means unusually expensive batteries must be used to obtain the necessary battery life.
Potential health hazards
More car accidents are related to drivers who were talking through a mobile device. Cell phones may interfere with sensitive medical devices. There are allegations that cell phone signals may cause health problems.
• Human interface with device
Screens and keyboards tend to be small, which may make them harder to use. Alternate input methods such as speech or handwriting recognition require training.
Portable computing devices
There are several categories of portable computing devices that can run on batteries but are not usually classified as laptops: portable computers, keyboardless tablet PCs, Internet tablets, PDAs, Ultra Mobile PCs (UMPCs) and smart phones.
Carputer
A Carputer is a computing device installed in an automobile. It operates as a wireless computer, sound system, GPS, and DVD player. Also contains word processing software and its bluetooth compatible.
Mobile Computing Application Issues
The programs used in mobile devices like mobile phones, laptops, palm computers, etc. for internet connectivity and other computer related activities are called mobile computing applications. The various issues and designs of mobile computing application considerations, system availability design and security issues. The technical design plays a key role in a mobile computing project and offers unique challenges to the system professionals
Network Design
Issues regarding Wireless LAN design and Wide Area Radio Network Design which network design comprises are discussed below.
Wireless LAN design issues
• The number of mobile users who will use wireless LAN and the number of them active during the peak period.
• The types of LAN application accessed by them. (Keeping in mind that wireless LANs will not be acceptable for the intended users as they operate at much slower speeds than wired LANs).
• Use of notebook with a wireless NIC as a primary and user device.
Data compression considerations:
As the bandwidth of wireless network is scarce & inexpensive it is necessary to compress data to get the maximum out of this bandwidth. This is usually done in the modem by going beyond the modem hardware in reducing the quantity of traffic on wireless networks using client application programs
Conclusion:
The world of personal computing is becoming more connected. The advent of the World Wide Web has caused an explosive growth in the population of Internet users. Everyday new members join the network community. It is changing the way we work, the way we think. Everyday one reads another story about the ``global network'' and the way it is changing the world. Major computer companies have built entire advertising campaigns around this very idea, and the future promise of bringing it about. Providing on-line services to the home user has become a multi-million dollar business. become used to, and have come to expect, quick response times. Even as we move to a more decentralized, remote model of computing our expectations stay the same. In fact, the spread of graphical interfaces and multimedia has only served to increase our expectations. The effect on the computing world of the graphical, multimedia based nature of the Web stands as testimony to this.