Research Paper

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Wireless Fidelity      In the last few years the world has undergone a tremendous and unprecedented technological change with the attack of the Information Technology revolution. Earlier it was e-mail that changed the way people communicate, and then online shopping became the order of the day, gradually online banking caught up and the list goes on and on. The new trend, Wi-Fi, or Wireless Fidelity, allows you to connect to the Internet from your couch at home, a bed in a hotel room or at school, all without wires. As author Harold Davis nicely puts, “Wi-Fi is a wireless technology just like a mobile phone and Wi-Fi enabled computers send and receive data indoors and out; anywhere within the range of a base…show more content…
IEEE 802.11b defines the physical layer and media access control (MAC) sublayer for communications across a shared, wireless local area network (WLAN). As Theodore Rappaport states, “At the physical layer, IEEE 802.11b operates at the radio frequency of 2.45 gigahertz (GHz) with a maximum bit rate of 11 Mbps. It uses the direct sequence spread spectrum (DSSS) transmission technique. At the MAC sublayer of the Data Link layer, 802.11b uses the carrier sense multiple access with collision avoidance (CSMA/CA) media access control (MAC) protocol” (35). A wireless station with a frame to transmit first listens on the wireless medium to determine if another station is currently transmitting (this is the carrier sense portion of CSMA/CA). If the medium is being used, the wireless station calculates a random backoff delay. Only after the random backoff delay elapses can the wireless station again listen for a transmitting station. By instituting a random backoff delay, multiple stations that are waiting to transmit do not end up trying to transmit at the same time (this is the collision avoidance portion of CSMA/CA). Collisions can occur and, unlike with Ethernet, they might not be detected by the transmitting nodes. Therefore, 802.11b uses a Request to Send (RTS)/Clear to Send (CTS) protocol with an Acknowledgment (ACK) signal to ensure that a frame is successfully transmitted and received.      The 802.11b
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