TAXI Region Campus City In-Building Figure 1

Figure 2 USA market millions 1995 2000 10 20 30 40 50 60 70 80 90 100 10 20 30 40 50 60 70 80 90 100 Internet users paging subs laptop users cellular + PCS subs annual laptop sales dedicated wireless data subs millions Figure 2

Figure 3 LOCAL AREA PACKET SWITCHING WIDE AREA CIRCUIT SWITCHING User Bit-Rate (kbps) Ethernet FDDI ATM 100 M Polling Packet Radio 1st gen WLAN 2nd gen wired- wireless bit-rate "gap" 1970 2000 1990 1980 .01 .1 1 10 100 1000 10,000 100,000 YEAR WIDE AREA CIRCUIT SWITCHING 14.4 digital cellular 28.8 modem ISDN 9.6 modem 2.4 modem 2.4 cellular 32 kbps PCS 9.6 cellular wired- wireless bit-rate "gap" Figure 3

Figure 4

Figure 5 Received Signal Power (dB) dB With Respect to Average Value 0.5 0.5l 1.5 -30 -20 -10 10 1 t, in seconds 30 20 x, in wavelength Received Signal Power (dB) Figure 5

Figure 6 Received Signal Power (dB) log (distance) With path loss and shadow fading Received Signal Power (dB) With path loss, shadow fading, and Rayleigh fading With path loss log (distance) Figure 6

Hierarchical Star Peer-to-Peer Figure 7

BASE STATION Figure 8