Alamouti Encoding-Decoding 2
Posted by Ujjval Shah on Sunday, March 8, 2009
Under: Simulation
The simulation is complete.
As discussed in previous post, the entire simulation of a siso and mimo (with alamouti scheme) has been done.
Entire simulation is done for QAM Modulation. But the same can be realised for other modulation schemes too as only the values of the complex symbols (values I and Q) are going to change with modulation scheme and the Alamouti encoding remaining constant.
Two major impairments are included in the simulation- The Additive White Guassian Noise (AWGN) and Rayleigh's Flat Fading (Jake's Model). The simulation shows the effect on signal constellation and the BER due to the Alamouti coding scheme for 1 receiver antenna.
Alamouti's main purpose is to protect the symbols from fading. This is done by providing diversity as it has been discussed in the previous theory posts. As it can be seen from the block diagram, the encoder output is fed to two instances of Jake's Fading Model, hence the probability of the path gains of both the models going down simultaneously is almost next to zero. Both the signals are later added and then Maximum Likelihood detection is performed to find out the symbols.
A snapshot of the Front Panel as well as the Block Diagram are shown below:
FRONT PANEL
Without using Alamouti Scheme:
Using Alamouti Scheme:
In : Simulation