... scheme for the systems of IMT-2000 and beyond. 3.2.3 Principles of DS-CDMA and IS-95This section reviews the principle of DS-CDMA, on which the 3G systems and beyond arebased, and discusses ... standards summaryStandard 802.11 802.11a 802.11b 802.11gDate standard July 1997 September September July 2003approved 1999 1999Frequency 2 .4- 2 .48 35 GHz 5.15-5.35 GHz 2 .4- 2 .48 35 GHz 2 .4- 2 .48 35 ... Mbps) (6, 9, 12, 18, 24, DBPSK QPSK DQPSK 36, 48 , 54 Mbps)(1 Mbps DSSS) (12, 18 Mbps) (2 Mbps DSSS) OFDM (6, 9, 12, 18,4GFSK 16QAM DBPSK 24, 36, 48 , 54 Mbps)(2 Mbps FHSS) ( 24, 36 Mbps) (1 Mbps...