re weight than the jammed metric values. With no jammer state information c(0) = c(1). (4.134) With continuous jamming (p = 1), the jammer always exists and all metrics are weighted the same. 4.11.2 FH/MFSK with Partial-Band Noise Jamming Table 4.2 gives the expressions for parameter D for FH/MFSK systems with partial-band noise jamming where p is the fraction of the spread-spectrum band being jammed. Here p = 1 corresponds to broadband jamming. The soft decision metric is m(y,x;z) = (((c(z)ex (4.135) while the hard decision metric is m(y, X. (4.136) As with DS/BPSK c(z) has the form (4.133) when there is jammer state FH/MFSK Jammer Metric State Ro = log2M Information Broad-band D= D= min M-1 M-2 Partial-band D=pl D= and M-1 References Table 4.3. Code functions Pb < G(Dm); E = REblm G(X) = 1 X log2M G(X) = 1MX G(X) = G(X) = 1[7X15 + 8X¹6 + 22X17 + 44X18 + G(X) = 1[7X + 39X8 + 104X9 + 352X10 + 1187X¹1 + . . . ] G(X) = 1[XX + 4X8 + 8X9 + 49X10 + 92X¹ knowledge and (4.134) when there is no jammer state knowledge. Table 4.2 also shows the diversity parameter m. 4.11.3 Coding Functions Table 4.3 shows some typical coding functions which depend only on the alphabet size M. The M = 2 cases apply to both DS/BPSK and FH/BFSK. Diversity m > 1 is used only for the FH/MFSK systems. Examples of other codes will be given in Part 2, Chapter 2. 4.12 REFERENCES [1] R.G. Gallager, Information Theory and Reliable Communication, New York: John Wiley, 1968. [2] A.J. Viterbi and J.K. Omura, Principles of Digital Communication and Coding, New York: McGraw-Hill, 1979. [3] G. C. Clark, Jr., and J. B. Cain, Error-Correction Coding for Digital Communications, New York: Plenum Press, 1981. [4] J.M. Wozencraft and R. S. Kennedy, "Modulation and demodulation for prob- abilistic coding," IEEE Trans. Inform. Theory, IT-12, July 1966, pp. 291-297. J.L. Massey, "Coding and modulation in digital communications," Proceedings International Zurich Seminar on Digital Communications, Switzerland, March 12-15, 1974. [6] A. J. Viterbi, "Spread-spectrum c