What is the transmit power limit for Wi-Fi 6E operation in the 6 GHz band in the United States?

What is the transmit power limit for Wi-Fi 6E operation in the 6 GHz band in the United States? The FCC (47 CFR Part 15, Subpart E) defines three device categories for 6 GHz operation, each with different power limits and operating rules: (1) Low Power Indoor (LPI): maximum EIRP: 30 dBm (1 W) for channel bandwidths ≤ 160 MHz. Power spectral density: 5 dBm/MHz maximum. For 320 MHz channels (Wi-Fi 7): 30 dBm EIRP still applies (5 dBm/MHz × 320 MHz = 30 dBm). Usage: indoor APs and clients. No AFC required (simplified deployment). Restriction: must be used indoors only. Outdoor operation is prohibited. The device must have compliance mechanisms (e.g., geo-fencing, indoor/outdoor detection) to prevent outdoor use. Fixed or mobile devices. (2) Standard Power (SP): maximum EIRP: 36 dBm (4 W) for APs. Power spectral density: 23 dBm/MHz maximum. Client devices: 30 dBm maximum EIRP when associated with an SP AP. Requires AFC (Automated Frequency Coordination): the AP must query an AFC database to verify that its transmission will not interfere with incumbent fixed microwave links. AFC determines the available channels and maximum allowable power at the AP location. Can be used indoors and outdoors. (3) Very Low Power (VLP): maximum EIRP: 14 dBm (25 mW). Power spectral density: -8 dBm/MHz. Usage: portable and wearable devices (smartphones, tablets, XR headsets). No AFC required. Can be used indoors and outdoors. Very short range (5-10 m typical). (4) PA design implications: for LPI AP (30 dBm EIRP, 160 MHz): the PA must deliver approximately 25-28 dBm at the antenna input (accounting for 2-5 dB antenna gain). For 4×4 MIMO: power is shared across streams, so per-chain PA output ≈ 19-22 dBm. This is well within the capability of standard GaAs HBT PAs. For SP AP (36 dBm EIRP): higher PA output is needed. With a 5 dBi antenna: PA output = 31 dBm. For 4×4 MIMO: per-chain ≈ 25 dBm. Requires a higher-power PA module or external PA.