How does 802.11a differ from 802.11g?

The IEEE 802.11 Task Group G was formed to develop a new protocol for the extension of the IEEE 802.11b (2.4 GHz) physical layer-802.11g. This new protocol promises to enhance the performance and possible application of Wi-Fi networks by increasing the data rate of 802.11b-type devices above 20 Mbps. This will improve access to both fixed wired and wireless LANs as well as create higher-performance ad hoc networks. Currently, there are two proposals under consideration: Intersil has proposed a version of OFDM, and Texas Instruments has proposed its Packet Binary Convolution Coding (PBCC). The benefits of the 802.11g protocol's speed and compatibility with 802.11b are obvious. Unfortunately, it remains mired in a standards battle and approval process.