Slide Show on Diversity Reception
Site (or macro) diversity
- Receiving antennas are located at different sites.
For instance, at the different corners of hexagonal cell.
- Advantage: multipath fading, shadowing, path loss and
interference are "independent"
Polarization diversity
- Obstacles scatter waves differently depending on
polarization.
Angle diversity
- Waves from different angles of arrival are combined
optimally, rather than with random phase
- Directional antennas receive only a fraction of all
scattered energy.
Frequency diversity
- Each message is transmitted at different carrier
frequencies simultaneously
- Frequency separation >> coherence bandwidth
Time diversity
- Each meesage is transmitted more than once.
- Useful for moving terminals
- Similar concept: Slow frequency hopping (SFH):
blocks of bits are transmitted at different carrier
frequencies.
Slide on Diversity from Short Course in Wireless Communication at U.C. Berkeley
JPL's Wireless Communication Reference Website Slide Show