In addition to increasing the bandwidth used in standard intervals are reduced. In fact, almost dou

Standard 802.11 a, the new radio spectrum for wireless local area networks and broadband wireless mutual distributing networks increases up to 54 Mbps. This remarkable increase mutual distributing in bandwidth modulation technique called OFDM is owed.
Standard 802.11 a, the new radio spectrum for wireless local area networks and broadband wireless networks increases up to 54 Mbps. This remarkable increase in bandwidth modulation technique called mutual distributing OFDM is owed. Rate data transmission in IEEE 802.11 a standard are: 6, 9, 12, 18, 24, 36, 48, 54 Mbps based on the standard, supports speeds of 6, 12, 24 Mbps is required. Some experts wireless LAN standard IEEE 802.11 a next-generation IEEE 802.11Tlqy and even some products such as chips, Atheros Network Card PCMCIA / Cardbus Card Access Inc. product IEEE 802.11 a standard has been implemented.
Undoubtedly the wide bandwidth and fast data rate limitations as well. The increased bandwidth in IEEE 802.11 a standard has made its operating range compared with IEEE 802.11 / b decreases. In addition to increased overheads of protocol processing, interference, mutual distributing and correction of errors, the actual bandwidth is far less than the nominal bandwidth of this standard. In many applications, feasibility and installation of additional equipment is required which in turn increases mutual distributing the cost of the wireless network infrastructure. Because the operating range of the standard operating range than in standard IEEE 802.11 b and therefore the access points or base stations will need to increase infrastructure spending to follow. The standard of a particular mutual distributing frequency band, known as the UNII uses. This frequency band is divided into three contiguous frequency as follows:
One of the misconceptions is the belief that the 802.11 standards 802.11 a 802.11 b before the operation is located. The second mutual distributing generation of the 802.11 b wireless standards (after 802.11) and 802.11 a third generation of this standard is set. Many vendors claim the standard 802.11 a 802.11 b wireless equipment can not be replaced because mutual distributing the physical layer used in fundamentally different from each other. The throughput (data rate) is different in each interval.
In Figure 4, 1 the three operational areas UNII and also authorized the FCC RF radiation are considered. mutual distributing They provide a work area of 12 frequency channels. UNII 1 band for indoor applications, indoor and outdoor applications UNII 2 bands, and band UNII 3 for outdoor applications and can be used to bridge the network. These areas are usable frequency in Japan. This standard is currently not available in Qarharvpa. In Europe HyperLAN 2Bray used wireless network that uses the same frequency band 802.11 a. One of the interesting points is defined in the standard 802.11 mutual distributing a bridge network applications in indoor and outdoor applications. In fact, the standard rules for communication between the bridge and the bridge on the network provides outdoor and indoor applications. Generally can be classified in one of the three following features and benefits 802.11 a summarized. Increase in bandwidth compared to standard 802.11 b (standard 802.11 a maximum bandwidth of 54 Mbps) is. The use of the frequency spectrum alone (band 5 GHz)
Compared to the standard 802.11 a bandwidth of 11 Mbps 802.11 b and Hdakr provides 54 Mbps bandwidth. The most important mutual distributing factor in a significant increase in the bandwidth of standard techniques using advanced modulation, OFDM is called. mutual distributing OFDM technique technology (IT) has evolved and matured in wireless applications are considered. This technology has considerable resistance against radio interference and multi-path effect is less than the phenomenon itself. OFDM under multi-carrier modulation or modulation of discrete Chndahngy known. This modulation technique in addition to the wireless network in the digital television (in Europe, Japan, and Australia) as well as the technology is used in ADSL lines. Andrew McCormick mutual distributing Andrew McCormik of Edinburgh University of Technology has collected some interesting interactive mutual distributing display that is visible in the address http://www.ee.ed.ac.uk/~acmc/OFDMTut.html.
QAM and OFDM technique of digital signal processing and data signals are multiplexed with precise frequencies. These frequencies are selected so as to provide orthogonality property and thus, despite the frequency overlap each single carrier frequency band apparent and does not frequencies are protected for spacing. For more information mutual distributing on this technique can refer to the following address:
In addition to increasing the bandwidth used in standard intervals are reduced. In fact, almost double the frequency band 5 GHz frequency band ISM (2.4 GHz), which is used in Astandard802.11 mutual distributing b. The effective range of standard mutual distributing and varies according to different wireless chip makers, but as a rule can be straightforward in standard intervals mutual distributing to a third frequency range 2.4 GHz (802.11 b) the assessment. Currently operating range (distance from the transmitter) in products based on 802.11 a bandwidth of 54 Mbps and 10 to 15 meters. These range in width Band6 Mbps