help regarding Diversity Techniques

Hi

In MIMO case with the increase of Number of antennas the BER performance also improving .Why it is improving? Plz explain me How?

Thanks in Advance

Ok

because MIMO system will use the multiple antenna to overcome the bad condition of the channel by using diversity method which will transmit the same data on multiple antenna so they can assure the arriving of the data.

To improve transmission over fading radio channels a diversity system is used. A
diversity system uses two or more channels. The idea of diversity is that these
channels should be as independent as possible and hopefully the fading dips of the
channels do not occur at the same time.

There are many types of diversity including Time diversity, Space diversity, Polarization Diversity; Frequency Diversity and Angle Diversity.

A MIMO-system (Multiple Input Multiple Output) is a system where the transmitter
and the receiver use multiple antennas. The antennas in the transmitter as well as the receiver are separated a certain distance from each other. The correlation between the individual channels depend on this distance.
The SNR is given simply as below:

(n×Es)\(m×N0)

Where "n" and "m" are the numbers of transmit and receive antennas respectively and "Es" is the signal energy and "N0" is the spectral density of the noise.

from this simple relation SNR can be controlled by controlling n,m and hece control the BER.

hope that this is helpfull.

this will give u some idea ...