The USA and Asia use different frequency bands and maximum signal strengths that are different than the European standard.
In the USA, three subbands, each 100 MHz wide, are used for wireless networks in the 5 GHz band. The "lower band" ranges from 5150 - 5250 MHz, the "middle band" ranges from 5250 - 5350 MHz and the "upper band" ranges from 5725 - 5825 MHz. In the lower band, a maximum average EIRP of 50 mW is permitted; in the middle band this is 250 mW and 1 W in the upper band.
In Japan, the use of the 5 GHz band is possible to a limited extent: only the lower band of 5150 - 5250 MHz is approved for private use.