Modeling of Digital Communication Systems Using SIMULINK

Chapter 9Digital Communications BER Performance in AWGN (Block Coding)

9.1 Digital Communications with Block Coding in AWGN

This chapter presents topics in the use of Simulink for evaluating block error control coding performance. Specific topics include:

• BER performance of BPSK in AWGN with the block error control codes
  • Hamming
  • Golay
  • Bose-Chaudhuri-Hocquenghem (BCH)
• BER performance of FSK in AWGN with Reed-Solomon (RS) codes
• BER performance of QAM in AWGN with Reed-Solomon codes
  • Multipath

9.2 BER Performance of BPSK in AWGN with a Binary BCH Block Code

A BCH code is a cyclic block code usually specified in terms of its generator polynomial. A binary BCH(n,k) code is represented by the following parameters:

1. n = 2^m−1 = code block length
2. k = message length
3. t = the number of correctable errors, (n−k ≤ mt)
4. = the minimum distance of the code
5. R_c = k/n = code rate

For example, BCH(31,16) has a code rate 16/31with a minimum distance = 7, capable of correcting t = 3 errors.

A Simulink model for estimating the BER performance of the BCH(31,16) code with BPSK modulation in AWGN is shown in Figure 9.1; for reference, a model for uncoded BPSK in AWGN is included in Figure 9.1. Model parameters are specified as follows:

Figure 9.1 BER Estimation of BPSK with BCH(31,16) in AWGN. ...