CyberCertPrepNetwork FundamentalsWireless BasicsEASYFree question
What Wi-Fi generation first introduced the 5 GHz band, and what was the primary reason 802.11b (2.4 GHz) achieved broader market adoption despite 802.11a being faster?
- A.802.11a achieved broader adoption than 802.11b; the question premise is incorrect
- B.802.11g first introduced the 5 GHz band; 802.11b was adopted first because it used 2.4 GHz which had better regulatory approval
- C.802.11n first introduced the 5 GHz band with MIMO; 802.11a and 802.11b were both 2.4 GHz only
- D.802.11a (1999) first used 5 GHz with up to 54 Mbps; despite being faster, 802.11b (1999, 11 Mbps, 2.4 GHz) achieved broader adoption because: 2.4 GHz has better wall penetration and range, 802.11b chipsets were cheaper, and 802.11a was incompatible with existing 2.4 GHz Bluetooth and 802.11b equipment
Why D is correct
Both 802.11a and 802.11b were ratified in 1999. 802.11a: 5 GHz, OFDM, up to 54 Mbps, UNII bands. 802.11b: 2.4 GHz, DSSS/CCK, up to 11 Mbps. 802.11b won the market because: (1) 2.4 GHz signals travel farther and penetrate walls better than 5 GHz. (2) 802.11b chipsets were significantly cheaper to produce. (3) 2.4 GHz had better global regulatory harmonization initially. 802.11g (2003) combined 802.11b's range with 802.11a's 54 Mbps on 2.4 GHz. 802.11n (2009) added 5 GHz dual-band support.
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