a bits are encoded into a codeword of 2040 coded bits. Concatenation of Codes REED - SOLOMON WORD ERROR PROBABILITY REED - SOLOMON BIT ERROR PROBABILITY 3233013 (7, CONVOLUTIONAL CODE AND (255, 223) REED-SOLOMON - CODE = VITERBI SOFTWARE DECODER = GEOMETRIC MODEL Eb /No. dB Figure 4.25. Non-interleaved performance statistics for concatenated coding scheme assuming no system losses; (7,1/2) convolutional code (reprinted from [14]). General Analysis of Anti-Jam Communication Systems 7461776427 (10, CONVOLUTIONAL (255,223) REED-SOLOMON CODE = VITERBI SOFTWARE DECODER = GEOMETRIC MODEL REED - SOLOMON WORD ERROR PROBABILITY REED - SOLOMON BIT ERROR PROBABILITY Eb INO. dB Figure 4.26. Non-interleaved performance statistics for concatenated coding scheme assuming no system losses; (10,1/3 ) convolutional code (reprinted from [14]). Concatenation of Codes INNER CODE (10, 1/2 INNER CODE (10, 1/h INNER CODE (7, 1 m INNER CODE Eb INO, BB 4.27. Comparison of concatenated channel decoder bit error rates with for ideal sev- Figure eral convolutional inner codes and a Reed-Solomon (255,223) outer code interleaving assuming no system losses (reprinted from [14]). General Analysis of Anti-Jam Communication Systems probabilities of the super channel formed. A natural approximation is to assume a symmetric Q-ary super channel characterized by the single para- meter Ps, the symbol error probability. For this model the super channel has conditional probabilities given by (4.79) with parameter Ds given by (4.81) and Rs given by (4.124). This type of symmetric Q-ary super channel occurs for many of the spread-spectrum systems considered earlier. For example, in a symmetric M-ary channel of the type considered earlier, collect L sym- bols to form Q-ary symbols for the outer channel where M L Q . (4.129) For the binary case with M = 2, the choice of L 8 gives the Q = 256 alpha- bet for the RS code. Similarly M = 4 and L = 4 also yields Q = 256. For these Q-ary symmetric channels the decoded bit error probability of the RS code Pb is dire