Wireless LAN

Centrino refers to the mobile wireless and power management technology by Intel. Centrino allows one to connect to the Internet or a corporate network without wires or an add-on adapter card. Wireless LAN (WLAN) uses radio waves to wirelessly connect computers to each other, with ability to connect to 802.11b, 802.11a, and 802.1 lg based infrastructures. It supports a wide range of industry wireless-LAN security standards. 

Wireless LANs are becoming increasingly popular as businesses are becoming more mobile and less centralized. You can see them most often in environments where standard cabling methods are not possible or wanted. However, they are still not as fast or efficient as standard cabling methods. Also, they are more susceptible to eavesdropping and interference than standard cabling methods. 

IEEE 802.11. LAN/MAN wireless LANS, [online]. Available http //standards.ieee.org/ getieee802/802.11. html. 

Prasithsangaree P, Kiishnamurthy P, Chrysanthis P (2002) On indoor position location with wireless LANs. The 13th IEEE international symposium on personal, indoor and mobile radio conununications, 2002, vol 2, pp 720-724... 

The audio and text are considered as high priority and the bandwidth needs do not raise problems. The video can be supported just when using the Wireless LAN/UMTS networks that allow big amount of data to be transferred. If the product manager invites one or more specialists in a collaborative session, the shared space component will be enabled. It allows the product manager to share resources such as documents, booklets, demo films, with the... 

M. Nakamura, Y. Yang, S. Kubota, H. Shimizu, Y. Miura, K. Wasaki, Y. Shidama, and M. Takizawa, "Network system for alpine ambulance using long distance wireless LAN and CATV LAN," Igaku Butsuri, vol. 23, no. 1 pp. 30-39,2003. 

IEEE Standard 802.11b-1999, Part 11 Wireless LAN Medium Access Control (MAC) and Physical Layer (PHY) Specifications — Higher-speed Physical Layer Extension in the 2.4 GHz Band, 1999. 

Marconi had a dream of a world connected by wireless devices, and as of 2011 that dream is coming true. The IEEE 802 wireless connectivity standards as of 2009 include a personal area network (Bluetooth) that will connect all the devices in a house, car, or office. It has an expanded wireless LAN standard that will support high-speed wireless access of home and office computers into an access point. Both the wireless home network and the wireless LAN can be tied into a high-speed wireless regional network, replacing the current fiber-optic networks. There will be several high-speed cell phone networks that can also tie into the regional wireless system, and when this is added to the current satellite-based wide area networks, the result could be the fully connected wireless world Marconi envisioned. 

One important application of spread spectrum communication systems is in the implementation of wireless local area networks (LANs). The attraction of such networks is obvious. A computer with access to a wireless LAN is completely untethered and a hard (wired) connection to a network is unnecessary. Wireless LANs are clearly advantageous in a situation in which computers are highly mobile (roaming), such as with laptop computers being moved from office to office or from an office to a conference room. Each computer carries its own RF transmitter and receiver, and such a system becomes very practical if licensing requirements can be avoided. 

For systems such as wireless LANs to operate without a FCC site license, the industrial, scientific, and medical (ISM) frequency bands were created. There are two such bands, 902-928 MHz and 2.400-2.484 GHz. The FCC requires that transmission on these bands must use either frequency hopping or direct sequence spread spectrum transmission. The more restrictive IEEE 802.11 standard, however, limits FHSS to the 2.400-2.484 GHz band, so that the lower frequency band is reserved for DSSS systems. FCC requirements also dictate certain parameters that influence the hopping pattern for FHSS systems. For example, the FCC dictates that in the 2.4-GHz frequency band, a FHSS transmitter must not spend more than 0.4 s in any one frequency slot every 30 s and that the transmitter must hop through at least 75 frequency slots in the frequency hopping pattern (Rigney, 1995). 

A primary application of wireless LANs optimizes the ease of access of the wireless technology. Portable or notebook PCs equipped with their own wireless LAN adapters can create an instant LAN connection merely by getting within range of a server-based wireless LAN adapter or wireless hub. In this way, a student or employee can sit down anywhere and log into a LAN as long as the user is within range of the wireless hub and has the proper wireless adapter installed in the portable PC. 

Wireless LAN An emerging networking system utrlizing radio or infrared media as the interconnection method between workstations. 

Generally, microwave teehnology is used in telecommunication, radars, wireless LAN, wireless access radios, satellite communication, navigation, paramagnetic resonance in combination with magnetic field, electron spectroscopy, heating and powered appliances, ete. 

Enterprises with wireless LANs can extend them seamlessly to remote locations, even with mobility. 

The short cell distances associated with IS-95 and related approaches make them useful in WLAN applications. Frequency hopping in the unlicensed 902-928 MHz band can provide 100 kbits s service for 30-300 users at campus distances. Most laptop and notebook wireless LAN connection... 

IEEE standard for information technology-telecommunications and information exchange between systems-local and metropolitan area networks-specific requirements—Part 11 Wireless LAN medium access control (MAC) and physical layer (PHY) specifications, IEEE Std 802.11-2012 (Revision of IEEE Std 802.11-2007), pp. 1-2793, Mar. 2012. 

Youngseok, L., Kyoungae, K., Yanghee, C. (2002). Optimization of APplacementand channel assignment in wireless LANs. n. Proceedings of the 27 th Annual IEEE Conference on Local Computer Networks, 2002, (pp. 831-836). IEEE Press. 

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