The channel capacity for the indoor radio frequency environment can be calculated based on the received signal strength and the corresponding noise level. The received signal strength depends on the transmit signal power level and the indoor radio frequency channel loss. According to the FCC rule, 1 W of transmit power is allowed at a spectrum of 1 MHz. This translates to a power spectrum density level of –30 dBm/Hz. On the other hand, the FCC rule clearly states that the transmit power spectrum density is limited at –32 dBm/Hz in every 3-kHz bandwidth. According to Figures 5.11 and 5.12, the worst case channel losses are 70 and 78 dB at less than 30 ft for frequency bands of 2.4 and 5.7 GHz, respectively. The channel capacity can be calculated according to
Equation 5.58