06-12-2012, 04:02 PM
OFDM-calculating SNR and BER using MATLAB
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OFDM(Orthogonal Frequency Division Multiplexing)
A large number of orthogonal, overlapping, narrow band subcarriers, transmitted in parallel, divide the available transmission bandwidth.
The separation of the subcarriers is theoretically minimal such that there is a very compact spectral utilization.
In wireless communication parallel transmission of symbol is applied to achieve high throughput and better transmission quality.
The idea of OFDM is to split the total transmission bandwidth into a number of orthogonal subcarriers in order to transmit the symbol rate using these subcarriers in parallel.
BER(Bit Error Rate)
In telecommunication transmission, the bit error rate (BER) is the percentage of bits that have errors relative to the total number of bits received in a transmission.
The BER is an indication of how often a packet has to be retransmitted because of an error.
SNR(Signal to Noise ratio)
The ratio of the amplitude of a desired analog or digital data signal to the amplitude of noise in a transmission channel at a specific point in time.
It measures the quality of a transmission channel or an audio signal over a network channel.
Calculation of SNR
Calculate the SNR when the power of both the signal and noise is measured across the same impedance.
Under this condition, the SNR may be calculated as SNR = Ps/Pn = (Rs/Rn)^2, where Rs is a measurement of an RMS amplitude (typically voltage) of the signal, and Rn is a measurement of an RMS amplitude of the noise.