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9 Qorvo 2020 Wi-Fi Standards If you are looking to buy a new wireless networking gear or a mobile device, you are overwhelmed by choices and abbreviations. Since Wi-Fi was first released to consumers in 1997, its standards have been continually evolving— typically resulting in faster speeds and network/spectrum efficiency. As capabilities are added to the original 802.11 standard, they become known by their amendment (802.11b, 802.11g, etc.). Table 1 lists different standards and max theoretical data rates achieved with those standards. Typical rates are lower than theoretical based on several factors, including the signal degradation with distance, modulation rate and forward error correction coding, bandwidth, MIMO multiplier, guard interval and typical error rates. The 802.11 family consists of a series of half-duplex over-the-air modulation techniques that use the same basic protocol. Here, we will discuss the basics of each Wi-Fi standard. 802.11-1997 Standard 802.11-1997 was the first wireless standard in the family, which was released in 1997, but is now obsolete. This standard defines the protocol and compatible interconnection of data communication equipment via the air in a local area network (LAN) using carrier sense multiple access protocol with collision avoidance (CSMA/CA). This protocol supported three physical layer technologies, including infrared operating at 1Mbps, a frequency hopping spread spectrum (FHSS) supporting 1Mbps and an optional 2Mbps data rate or a direct sequence spread spectrum (DSSS) supporting both 1Mbps and 2Mbps data rates. This protocol was not widely accepted because of interoperability issues, cost and lack of sufficient throughput. 802.11b Standard 802.11b products appeared on the market in mid-1999. It has a maximum theoretical data rate of 11Mbps and uses the same CSMA/CA medium access method defined in the original standard. The dramatic increase in throughput of 802.11b, along with substantial price reduction, led to wide acceptance of 802.11b as a wireless technology. 802.11b uses the ISM unlicensed frequency band from 2400MHz to 2500MHz. 802.11b is a direct extension of DSSS and uses complementary code keying (CCK) as its modulation technique. 802.11b is used in point-to-multipoint configuration where an access point communicates with mobile clients within the range of the access point. This range depends on radio frequency environment, output power and sensitivity of the receiver. 802.11b has a channel bandwidth of 22MHz, can operate at 11Mbps but scale back to 5.5Mbps, then to 2Mbps, then to 1Mbps (adaptive rate selection), in order to decrease the rate of re- broadcasts that results from errors. The 802.11b standard shares the same frequency bandwidth of other wireless standards. Thus, within the home, wireless devices such as microwave ovens, Bluetooth® devices, and cordless phones can cause interference with Wi-Fi. 802.11a Standard The 802.11a uses the same core protocol as the original standard. It operates at 5GHz and uses a 52-subcarrier orthogonal frequency division multiplexing (OFDM) with a maximum theoretical data rate of 54Mbps. This achieves a practical throughput of mid-20Mbps. Other data rates it supports includes 6Mbps, 9Mbps, 12Mbps, 18Mbps, 24Mbps, 36Mbps, and 48Mbps. 802.11a is not interoperable with 802.11b as they operate in different unlicensed ISM frequency bands. The 5GHz band gives 802.11a significant advantage because the 2.4GHz is getting crowded, but because of high carrier frequency, the effective overall range is less than 802.11b/g. ▲ Table 1 Chalk Talk: Qorvo's Wi-Fi Front End Solutions - a video interview with EE Journal