Information Transfer Via Radio (1)

Wireless Information Transfer Fundamentals

• Shannon's Equation
• Noise, T_sys >= 290 deg. K
• Bandwidth alone does not set channel capacity(bits/sec)
• For real-world systems, information is ~energy
• Propagation
• Radio propagation is dispersive rather than guided energy
• wire,cable,fiber vs. antenna
• The Pathloss Myth

(below, "Directional" means constant physical aperture/size )

• Isotropic-Isotropic Antennas
• Isotropic-Directional Antennas
• Directional-Directional Antennas
• Directed energy
• implies point-point instead of CSMA/CD(Ethernet broadcast) model
• multipath (self-generated "noise")