The popularity of WiFi comes at a price: Crowded spectrum. Partly to alleviate the spectrum congestion, the FCC recently adopted a rule which would increase the capabilities of software defined radios (SDRs). Cisco's 802.11a radios have just been certified by the FCC under the new rule, making them the industry's first WiFi SDR products. Cisco 802.11a radios currently provide 12 operating channels in the three 5GHz Unlicensed National Information Infrastructure bands. They will soon be field-upgradeable to support additional 11 channels between 5.4 and 5.7GHz, nearly doubling available network capacity.
We will soon see SDR-enabled devices such as handhelds, APs, and PDA's. As they will be using one radio instead of multiple radios, their prices will decline. Lower prices, however, will not mean lesser capabilities. These SDRs will be capable of dynamically switching across a wide range of frequency bands, transmission techniques, and modulation schemes. A user device with a single SDR could automatically switch between WiFi, WiMax, GSM, and CDMA infrastructure without losing connectivity.