Digital Trasmission over AWGN channel
Summary
- Introduction
- Geometric representation of M energy signals
- Review of the digital memoryless modulation techniques
Geometric representation of signal waveforms
The Gram-Schmidt procedure allows us to represent a set of M signal waveforms of duration T with a set of N < M functions Ψk(t) of a basis with duration T (k=1,..,N)
Geometric representation of signal waveforms (next)
Geometric representation of signal waveforms (next)
Geometric representation of signal waveforms (next)
Geometric representation of signal waveforms (next)
Geometric representation of signal waveforms (next)
Geometric representation of signal waveforms (next)
Geometric representation of signal waveforms (next)
Geometric representation of signal waveforms (next)
The r. v. ni e nk are uncorrelated and, since Gaussian are also statistically independent.
Given an arbitrary complete basis the componentsof a white signal are uncorrelated.
If the signal is Gaussian the components will be also indipendent.
Geometric representation of PAM signal waveforms
Since all the signals sm(t) are represented by a single basis function (namely, Ψ(t)), the PAM signalling is monodimensional (N=1).
Geometric representation of PAM signal waveforms (next)
Geometric representation of MPSK signal waveforms
Geometric representation of MPSK signal waveforms (next)
Geometric representation of MPSK signal waveforms (next)
The MPSK signalling can be obtained with two modulators PAM with carriers in quadrature.
The components must verify the requirement over the energy ⇒ They are not independent.
Geometric representation of MPSK signal waveforms (next)
QAM constellation
QAM constellation (next)
Orthogonal Signals
FSK Orthogonal Signals
Le lezioni del Corso
5. Digital Transmission over AWGN chanel
6. Evaluation of P(e) for optimum RX in AWGN
7. Error probability for M-PSK
8. Noncoherent ML Demodulation of FSK signals in AWGN
9. Transmission through bandlimited AWGN channels
13. Cyclic Codes
