Channel Modelling

Power Delay Profile

The Power Delay Profile \(p(\tau)\) gives the distribution of signal power received over a multipath channel as a function of propagation delays.  It is obtained as the spatial average of the complex baseband channel impulse response as $$ p(\tau) = R_{hh}(0,\tau)= E\left [  \left |  h(t,\tau) \right | ^2 \right...
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Digital Modulations

Simulation of M-PSK modulation techniques in AWGN channel

A generic simulation technique to simulate all M-PSK modulation techniques (for upto M=32) is given here. The given simulation code is very generic, and it plots both simulated and theoretical symbol error rates for all M-PSK modulation techniques (upto M=32). M-PSK Modulation and simulation methodology: The general expression for...
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BPSK

Intuitive derivation of Performance of an optimum BPSK receiver in AWGN channel

BPSK modulation is the simplest of all the M-PSK techniques. An insight into the derivation of error rate performance of an optimum BPSK receiver is essential as it serves as a stepping stone to understand the derivation for other comparatively complex techniques like QPSK,8-PSK etc.. Understanding the concept of...
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BPSK

Eb/N0 Vs BER for BPSK over Rician Fading Channel

In one of the previous article, simulation of BPSK over Rayleigh Fading channel was discussed. This article deals with simulation of another important fading type : Rician Fading. Rayleigh Fading: Rayleigh Fading model is used to simulate environments that has multiple scatterers and no Line Of Sight (LOS) path....
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Channel Modelling

Eb/N0 Vs BER for BPSK over Rayleigh Channel and AWGN Channel

The phenomenon of Rayleigh Flat fading and its simulation using Clarke’s model and Young’s model were discussed in the previous posts. The performance (Eb/N0 Vs BER) of BPSK modulation (with coherent detection) over Rayleigh Fading channel and its comparison over AWGN channel is discussed in this post. We first...
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Digital Modulations

BER Vs Eb/N0 for QPSK modulation over AWGN

In the previous article we saw about how QPSK modulation and demodulation can be done. This concept is extended further to simulate the performance of QPSK modulation technique over an AWGN. Transmitter: For the QPSK modulation , a series of binary input message bits are generated. In QPSK, a...
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Digital Modulations

BER Vs Eb/N0 for BPSK modulation over AWGN

In the previous article we saw about how Passband BPSK modulation and demodulation can be done. This concept is extended further to simulate the performance of BPSK modulation technique over an AWGN. Note that this is a baseband simulation of BPSK modulation and demodulation. Baseband simulation are faster and...
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Digital Modulations

BPSK modulation and Demodulation

BPSK Modulation: In digital modulation techniques a set of basis functions are chosen for a particular modulation scheme.Generally the basis functions are orthogonal to each other. Basis functions can be derived using ‘Gram Schmidt orthogonalization‘ procedure.Once the basis function are chosen, any vector in the signal space can be...
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Channel Modelling

Colored Noise Generation in Matlab

In communication systems the noise is mostly modeled as white noise. When there exists a noise that is “white” , then there must also exist a noise that is colored too. White noise has constant power spectral density across the entire frequency spectrum (extending upto infinity).There is no correlation...
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Channel Coding

Channel Coding

The next block in a communication system is the Channel coding block. There is an important difference between Channel coding and source coding. Source coding attempts to compress the data to improve bandwidth utilization, while Channel coding attempts to add redundancy to the data to make it more reliable...
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