IEEE 802.11y

IEEE 802.11y-2008 is an amendment to the IEEE 802.11-2007 standard that will enable high powered Wi-Fi equipment to operate on a co-primary basis in the 3650 to 3700 MHz band in the United States, except when near a grandfathered satellite earth station. It was approved for publication by the IEEE on September 26, 2008.
The US 3650 MHz rules allow for registered stations to operate at much higher power than traditional Wi-Fi gear (Up to 20 watts equivalent isotropically radiated power). The combination of higher power limits and enhancements made to the MAC timing in 802.11-2007, will allow for the development of standards based 802.11 devices that could operate at distances of 5 kilometres (3 mi) or more.

IEEE 802.11y adds three new concepts to 802.11-2007 base Standard:

Contention based protocol (CBP)- enhancements have been made to the carrier sensing and energy detection mechanisms of 802.11 in order to meet the FCC's requirements for a contention based protocol.
Extended channel switch announcement (ECSA)- provides a mechanism for an access point to notify the stations connected to it of its intention to change channels or to change channel bandwidth. This mechanism will allow for the WLAN to continuously choose the channel that is the least noisy and the least likely to cause interference. ECSA also provides for other functionalities besides dynamic channel selection based on quality & noise characteristics.
For instance, in 802.11y Amendment, the licensed operator can send ECSA commands to any stations operating under their control, registered or unregistered. ECSA is also used in 802.11n. In the 802.11n D2.0 implementation (which is shipping & undergoes Wi-Fi Alliance testing) 20MHz & 40MHz channel switching is provided for by the 11n PHY's ECSA implementation. Note that 802.11n is specified for operation in the 2.4GHz and 5GHz license exempt bands--but future amendments could permit 11n's PHY to operate in other bands as well.
Dependent station enablement (DSE)- is the mechanism by which an operator extends and retracts permission to license exempt devices (referred to as dependent STAs in .11y) to use licensed radio spectrum. Fundamentally, this process satisfies a regulatory requirement that dictates that a dependent STAs operation is contingent upon its ability to receive periodic messages from a licensees base station, but DSE is extensible to other purposes in regards to channel management and coordination.