IEEE 802.11g-2003

They are commonly used today in their 802.11a, 802.11b, 802.11g, 802.11n, 802.11ac and 802.11ax versions to provide wireless connectivity in the home, office and some commercial establishments.

Using the CSMA/CA transmission scheme, 31.4 Mbit/s[9] is the maximum net throughput possible for packets of 1500 bytes in size and a 54 Mbit/s wireless rate (identical to 802.11a core, except for some additional legacy overhead for backward compatibility).

[11] The modulation scheme used in 802.11g is orthogonal frequency-division multiplexing (OFDM) copied from 802.11a with data rates of 6, 9, 12, 18, 24, 36, 48, and 54 Mbit/s, and reverts to CCK (like the 802.11b standard) for 5.5 and 11 Mbit/s and DBPSK/DQPSK+DSSS for 1 and 2 Mbit/s.

The actual generation and decoding of orthogonal components is done in baseband using DSP which is then upconverted to 2.4 GHz at the transmitter.

The time domain signal is generated by taking an Inverse Fast Fourier transform (IFFT).

The advantages of using OFDM include reduced multipath effects in reception and increased spectral efficiency.

[12] The then-proposed 802.11g standard was rapidly adopted by consumers starting in January 2003, well before ratification, due to the desire for higher speeds and reductions in manufacturing costs.

Die shot of a Broadcom BCM2050KMLG, an RF CMOS chip used as a WiFi 802.11g radio [ 13 ]
Graphical representation of Wireless LAN channels in 2.4 GHz band. Channels 12 and 13 are customarily unused in the United States. As a result, the usual 20 MHz allocation becomes 1/6/11, the same as 11b.