6. • Similarly Transmit Diversity, if there are
multiple Transmit antenna.
• And it is also possible multiple transmit as
well as receive antenna than both Transmit
as well as receive diversity.
• Similarly we can send the signal at different
time slot it is called as Temporal diversity
7. • Similarly, signal is send at different carrier a
frequency called frequency diversity.
• Transmit the signal between different user
called multi user diversity.
• Hence Diversity play a major role to combat
fading and decrease the bit error rate and
improves the performance.
8.
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32.
33. Receive Diversity
• In a flat fading channel with 1 transmit
antenna and L receive antenna, , the channel
model is as follows:
• where the noise and independent
across the antennas.
34. • We would like to detect
• If the antennas are spaced sufficiently far
apart, then we can assume that the gains
are are independent Rayleigh, and we get a
diversity gain of L.
35. • With receive diversity, there are actually
two types of gain as we increase L.
• for the error probability of BPSK
conditioned on the channel gains:
36. • We can break up the total received SNR
conditioned on the channel gains into a product of
two terms:
• The first term corresponds to a power gain (also called
array gain): by having multiple receive antennas and
coherent combining at the receiver, the effective total
received signal power increases linearly with L:The second
term reflects the diversity gain:
