the cost and complexity of devices, and this solution may be inadequate indoors. This method also resolves fears that a mobile devices that constantly beacons its location could be used inappropriately by third parties to track a user's location. Beyond the 3650 band While the scope of 802.11y was limited to operation in the US 3650–3700 MHz band in the US, care was taken so that, if the light licensing concept was well received, it would not be necessary to start the 3+ year task group process in order for 802.11y devices to operate in other countries or in other frequency bands. As a result, lightly licensed 802.11 devices will be able to operate in any 5, 10, or 20 MHz channel that regulators make available by simply adding entries to the country and regulatory information tables in Annex I and J of 802.11. Other potential bands for 802.11y include: 4.9 GHz The regulatory classes and channel sizing needed to support the US public safety allocation at 4.9 GHz were added to 802.11-2007. DSE and ECSA will allow frequency coordinators to have dynamic control over channel access. 5 GHz Regulators and equipment manufacturers continue to debate the effectiveness of dynamic frequency selection (DFS) as a mechanism to avoid incumbent users in the 5 GHz bands. For example, Canada is not currently certifying 802.11 equipment for use in the 5600–5650 MHz band that is used by certain types of weather radars. 802.11y may provide a solution that will allow WLANs access to these bands. Firstly, DSE can be used to create exclusion zones around incumbent users; Secondly, when combined with DSE, the 802.11y device identification mechanism allows devices that cause interference to be denied further access to a channel within seconds. IMT-Advanced candidate bands (450–862, 2300–2400, 2700–2900, 3400–4200, and 4400–5000 MHz) Since 2003, the International Telecommunication Union (ITU) has been studying the potential for IMT-advanced services (aka systems beyond IMT-2000 or 4G) to use a number of frequencies between 450 and 5000 MHz for the next generation of cellular infrastructure. These systems will be capable of transmitting 100 Mb/s when mobile and 1000 Mb/s while stationary. Unfortunately, with the exception of a small amount of UHF spectrum that will become available upon the completion of the transition from analogue to digital television, these bands are occupied on a piecemeal basis by incumbent users that are not easily relocated. Extensive sharing studies