trường hợp khi nó không còn là một CPE nhưng thẻ được cài đặt trong máy tính xách tay một số. Một truy cập du canh du cư, thể hiện trong hình , là một truy cập mà người sử dụng hoặc thuê bao có thể di chuyển trong một khu vực hạn chế, ví dụ như trong một căn hộ hoặc một khuôn viên nhỏ. | Frequency Utilisation and System Profiles 39 Table Transmit spectral mask parameters 1 . A B C and D are in MHz Channelisation MHz A B C D 20 10 widely announced WiMAX frequency band. We here mention that third-generation 3G cellular systems operating in the GHz band as an extension band for these systems have been reported. License-exempt bands 5 GHz. The 2004 WiMAX unlicensed frequency fixed profile used the upper U-NII frequency band . the GHz frequency band see Table . In the future various bands between 5 GHz and 6 GHz can be used for unlicensed WiMAX depending on the country involved. Table shows globally the present expected WiMAX frequencies around the world. Other frequencies are sought. These frequencies should not be higher than the GHz already chosen because for relatively high frequencies GHz is itself not a very small value NLOS operation becomes difficult which is an evident problem for mobility. The Regulatory Working Group RWG introduced in Chapter 2 is trying to define both new frequencies reports talk about 450 MHz and 700 MHz and also the conditions for an easy universal roaming with possible different frequencies in different countries. Regulator requirements mainly allow both Time Division Duplexing TDD and Frequency Division Duplexing FDD . The attributed frequency spectrum size is a function of the country. Some elements about the WiMAX situation in some countries are given below. France In France as elsewhere the authorities wish to have at least fixed broadband access in the highest possible percentage of the territory. WiMAX has been seen as a means to provide this broadband access. Altitude Operator owned by Iliad has a WiMAX license in the GHz band. Altitude obtained it in 2003 when the regulating authority Autorité de Regulation des Telecommunication ART accepted that Altitude takes a WLL license owned and not used by another operator. Since then ART has .
