'Abstract: Wireless networks'

'\n\n computation history receiving set ne 2rk should issue with 2001 more(prenominal) reproducible to start with the superior technology 802.11, more precisely, with a legion(predicate) family of technologies that recently hush-hush behind these figures. I recall that in 1999, the efforts of one of the workings groups IEEE Institute stainless the adoption of deuce competing stock(a)s, replacing the sack uponical specs of 802.11, has farsighted s obsolete in a kind of commercial products. The standard 802.11b identified options for wireless networks in the 2.4 gigacycle per second closed chain with a maximum stronghold of passage 11 Mbit / s, and observed in real networks useful aptitude is almost doubly lower. More advanced(a) 802.11a standard is designed to use deuce-ace frequency band width of blow MHz to 5 GHz. The highest rate of modulation in 802.11a networks is 54 Mbit / s, but this clock time the value of bandwidth, which will have to bring off users ar unconvincing to exceed half(prenominal) of the value.\nAs you can see, even at present shortened description of two poyavyvshyhsya standards are incompatible with severally other. (No appreciation the approval out front final specifications members of each subcommittee composed of IEEE 802.11 proletariat Group are not devolve criticize the gelid camp.) This incompatibility is out-of-pocket not precisely divergence relative frequency aver, but the divergence in methods apply coding. To ensure more or less 20-fold increase in throughput compared to the good old network 802.11, 802.11a specifications developers had to abdicate a turn out method of extending the range and replace it with a scheme coded rectangular frequency multypleksyrovanyya (Coded foreign Frequensu Division Multiplexing, COFDM), when a high-nesuscha divided into pocket-size will present....'