rate of 8% In OFDM, the orthogonal subcarriers are generated when sending a payload of 1024 bytes, as compared to mathematically using the inverse Fourier transform (IFT), a sensitivity of -80 dBm for the same frame-error rate or rather its discrete equivalent, the inverse discrete and payload length at a data rate of 2 Mbps. Fourier transform (IDFT). The IDFT may be expressed as: 802.11a and OFDM In the search for ways to communicate at even higher data rates than those applied in 802.11b, a completely j j.sin(2nmn/N) different modulation scheme, OFDM (orthogonal fre- x(n) are complex sample values in the time domain, quency division multiplexing) was adopted for 802.11a. It is not DSSS yet it has a channel bandwidth similar to n = 0...N - 1, and X(m) are the given complex values, the DSSS systems already discussed. The 802.11a sup- representing magnitude and phase, for each frequency in plement is defined for channel frequencies between 5.2 the frequency domain. The IDFT expression indicates that the time domain signal is the sum of N harmonically and 5.85 GHz, obviously not compatible with 302.11b related sine and cosine waves each of whose magnitude signals in the 2.4 GHz band. However, since the channel occupancy characteristics of its modulation are similar to and phase is given by X(m). We can relate the right side of that of DSSS Wi-Fi, the same system was adopted in the expression to absolute frequency by multiplying the IEEE 802. 11g for enabling the high data rates of 802.11a arguments 2mn/N by fs/fs to get on the 2.4 GHz band, while allowing downward com- patibility with transmissions conforming to 802.11b. 802.11 specifies data rates of 6, 9, 12, 18, 24, 36, 48, and 54 Mbit/s. As transmitted data rates go higher and j-sin(2mmf(nts)] (5.2.1) higher, the problem of multipath interference becomes more severe. Reflections in an indoor environment can where f1 is the fundamental subcarrier and the difference result in multipath delays on the order of 100 nsec but between adjacent subcarriers, and ts is th