Wireless and mobile computing articles

Wireless Communication Platforms for LANS (04/22/2012)
... A wireless client must first be authenticated, and then associated with an access point before it can perform any communications. Enterprises that have a strong mobile e-commerce strategy must make a selection from the major wireless LAN specifications available in the market today. 802.11b The 802.11b specification was defined by the Institute of Electrical and Electronics Engineers (IEEE)....

Wireless Attacks ~ Jamming (Denial of Service) (04/21/2012)
...6MHz Cordless phones, television, RC cars, aircraft/police/business radios Ultra High Frequency (UHF) 328.6MHz to 2.9GHz Police/fire radios, business radios, cellular phones, GPS, paging, wireless networks, cordless phones Super High Frequency (SHF) 2.9GHz to 30GHz Terminal doppler weather radar, various satellite communications Extremely High Frequency (EHF) 30GHz and above Government radio astronomy, military, vehicle radar systems, ham radio NOTE A frequency is the numerical representation of the number of times a sine wave oscillates per second. Let's say you are listening to 101....

How Do I Share Pictures on the Web (04/11/2012)
... This type of photo sharing enables people all over the world to participate in the experience, just as if they were all sitting together around the kitchen table with an open photo album. Some printing services, such as Kodak's EasyShare Gallery (http://www.kodakgallery.com) and Shutterfly (http://www.shutterfly....

Wireless Industry Standards (04/10/2012)
... The IEEE does not provide certifications of any kind for their specifications. Wireless Application Protocol (WAP) Forum offers a comprehensive certification and interoperability testing program that covers device testing, content verification, and a set of authoring guidelines to assist developers in providing interoperable WAP applications and services. Wireless Ethernet Compatibility Alliance (WECA) seeks to attest interoperability of products based on the 802.11b specification, and certify them Wireless Fidelity (Wi-Fi) compatible. They endorse Wi-Fi as the global wireless LAN standard across all market segments Many other organizations such as the W3C, Wireless DSL Consortium, and other institutions have standards directly affecting the wireless industry, though they are not specific to wireless communications....

Broadband Wireless Communications (04/06/2012)
... AMPS did not support text messaging or data support. Due to the analog nature of the system, AMPS signal were easily intercepted using frequency scanning tools and were hence susceptible to eavesdropping. Another major flaw with the AMPS was the lack of cell phone authentication, which led to toll fraud on the basis of phone cloning. Global System for Mobile communications (GSM) is the most popular and widely used mobile telephony standard. GSM technology was initially introduced in the early 90's....

No Wires, Only by Bluetooth! (03/21/2012)
...15 standards. It was invented to get rid of wires. Bluetooth is more suited for connecting two point-to-point devices, whereas WIFI is an IEEE standard intended for networking. Bluetooth technology relies on two things, a radio frequency technology and the protocol software enabling it to transmit data to other devices. Bluetooth-capable devices can transmit data to other devices not within the line of sight of the user....

RFID Tags: What They are, how they are used and Why You Need a RFID Consultant (03/18/2012)
... Who uses RFID tags? RFID tags are used in a wide range of applications in industry, government, defense and healthcare. They are used to track and monitor inventory, monitor and locate valuable assets, provide secure identity cards or fobs for premisis access, to track disaster victims in an evacuations and for easy and secure contactless payment systems. The greatest advantage of RFID is that it greatly speeds the acquisition and processing of information, since line of site and close physical interaction between the tag and the reader is not necessary, as it is with bar codes and other identification technologies. The applications for RFID systems are continually expanding. How are RFID systems implemented....

HOW WIRELESS CAN CHANGE THE WORLD (12/13/2011)
... • The poor may not be literate enough to make use of equipment and connectivity even when available. The issue of the digital divide is beginning to evolve into a drive towards realizing the digital dividend. The digital dividend focuses on how to use technology to improve the economic possibilities of global society. Some of the key principles that will enable a digital dividend include: • Access vs. ownership....

History of voice Communications (12/12/2011)
... Of course, wires still had their place because radio was not always the most reliable medium. The environment, weather, time of day, and man-made interference could interrupt communications. Telephone technology advanced steadily, and telegraphy still found a place in data communications in the form of the telegram. Radio technology advanced throughout the 1930s with the notable invention of frequency modulation (FM), which provided better sound quality and was more resistant to interference than the older AM broadcasting system. One of the first applications for FM was police radio; it was ideal for mobile communications....

PDA and Pocket PC Technologies (12/12/2011)
... Others are more generic and can run many different applications, such as the Palm Pilot or Visor. All, however, fall into two categories: They either use public cellular for communications or they use other public or private networks. They all share the same limitations for data transmission, and they are limited to the current state of the art of the physical access channel. Except for Ricochet, this means 19.2 Kbps or less....

WIRELESS EFFICIENCY (12/08/2011)
... The activities pictured add more detail to a child’s birthday party, a friend’s graduation, or scuba diving on that Caribbean vacation. Now think about what you do after you get the pictures developed (assuming you don’t leave the film in a drawer for a year). The natural inclination is to show others. Why do we do it? To share the emotions that we felt when the pictures were taken. Whether you were there when the picture was taken or not, you’re still fair game when those pictures come back from the photo lab....

Wireless Antennas (12/05/2011)
... The RF Basics: An Introduction to the Antenna Theory There are two main characteristics in antennas: gain (or power amplification) provided by an antenna, and beamwidth (which shapes the antenna coverage zone). In fact, it makes sense to look at the zone of coverage as a third variable, because side and back beams of some antennas are difficult to describe in terms of beamwidth. You should always demand the antenna irradiation pattern diagram from the vendor to assess the shape of the antenna irradiation (if only approximately). A future site survey will show how closely the provided diagram corresponds to the truth. Another often overlooked antenna characteristic is the antenna polarization, which can easily be changed by altering the antenna position....

Wireless Internet (12/04/2011)
... Now a mobile businessman can be more productive because he can access his data in his office or retrieve data stored from a global Internet connection. As the performance of the Wireless Internet approaches that of a fixed connection, there is no longer a need to remain tethered to a desk. There are two types of Wireless Internet connections: those through cellular and those through a mobile data network. There is a very big distinction between these two types of connection. Cellular has traditionally been a circuit-switched connection, whereas mobile data networks are packet based....

WiMAX: The Upcoming Wireless Technology (09/16/2011)
... OFDMA adds some useful features to this modern application, which include high throughput, support to advanced antennas and great performance. Such features are not seen in the existing wireless communication technology implemented over wide area networks. This technology is designed to facilitate laptop users to connect with World Wide Web, without having a physical connection. WiMAX is launched to convince the users of cable and DSL to go for WiMAX, which is a best alternate. This latest technology is fulfilling all the requirements of what is needed by a wireless network....

Mobile phone users outnumber landline users (06/03/2011)
... Since then, there has been a tremendous growth in the field. Even though the period between 1985 and 1990 saw a slower pace in further developments in the mobile services field, nineties reflected a positive attitude towards the market. India's 1st Mobile service provider was 'MobileNet' which was later acquired by Bharti Airtel. Competition went up as new players tried their hands in the mobile segment. Now, more than 26 mobile service providers are providing cellular services in India....

Proprietary Networks (09/21/2010)
... Modulation at the physical layer is Gaussian Frequency Shift Keying (GFSK). RICOCHET Ricochet is the only wireless packet data network today that was built from the ground up to handle high speed data, up to 128 Kbps. Modems are available from third-party sources that allow connection to laptop computers by at least one Pocket PC. The network has about 41,000 customers in 15 markets as of July 2001 but the parent company, Metricom, has filed for Chapter 11 in bankruptcy court, so anything could happen to Ricochet. On August 8, 2001, Metricom ceased operations of Ricochet but the company is negotiating with third parties to buy the Ricochet network....

How to handle and maximize the battery performance of a mobile computer (09/16/2010)
... Also powers the RTC chip when the computer is switched off. There are four main battery types: • Alkaline. Normally used in palmtop computers. These are the batteries that you use in calculators and TV remote controls. • NiCad (Nickel-Cadmium)....

Wireless WANS (08/25/2010)
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Facilitators of a Wireless Environment (08/24/2010)
... Symbol: The leading manufacturer of wireless devices and scanners for retail, utilizing the latest technology in bar code scanning. Wireless devices add value to the enterprise only when they connect to the IT infrastructure and are actively supported by the administration. Access points, network cards, and other components essential to the deployment of a wireless communications infrastructure are available from several vendors, including: 3Com Cisco Fujitsu HP IBM Siemens Note With the wireless infrastructure in place, it is important to choose the right carrier to facilitate high-quality communications. Wireless Operators Wireless operators are organizations that provide the hardware and communications infrastructure to make wireless transmission possible in a wireless LAN and/or a wireless WAN environment. Most of these provide basic wireless phone services and many of them now offer services to transmit data in various forms....

Wireless Network Privacy ~ Advantages and disadvantages of RC4 Encryption (08/18/2010)
... Encryption is typically accomplished with the assistance of an external piece of data, which often comes in the form of a user-selected password or pass phrase. This not only makes the encryption stronger by enforcing a unique key, but it also keeps anyone who does not know the password from accessing the data. There are two main types of encryption: symmetrical and asymmetrical. Each has its strengths and weaknesses and is best suited to specific applications. Symmetrical Encryption The symmetrical encryption and decryption processes are both accomplished using the same key....