Chapter 4Digital Communications BER Performance in AWGN (MPSK & QAM)

4.1 MPSK and QAM Error Rate Performance in AWGN

This chapter continues the development of Simulink models for coherent modulations including multi-phase PSK (MPSK) and quadrature amplitude modulation (QAM). Topics presented here are listed as follows:

  • MPSK BER Performance (floating point)
  • MPSK BER Performance (fixed point)
  • QAM BER Performance
    • Average power
    • Peak power
    • Nonlinear amplifiers

4.2 MPSK Simulink Model

In MPSK, it is assumed that k information bits are assigned to M = 2k equal-energy signals. As a specific example, Figure 4.1 displays the Simulink model for determining the symbol error rate (SER) and BER performance for MPSK modulation with k = 6 and M = 64.

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Figure 4.1 MPSK Simulink Model with M = 64.

The parameters in the MPSK modulator block are displayed in Figure 4.2. Note that in this simulation the parameters M and k must be entered in the MATLAB command window prior to executing the model. Gray coding is stipulated as well. The AWGN block parameters are displayed in Figure 4.3.

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Figure 4.2 MPSK Input Parameters.

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Figure 4.3 AWGN Parameters for MPSK Simulation.

In the AWGN block, ...

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