moryless channel is assumed. Spread-Spectrum Multiple Access with FH/MFSK Waveforms (2.30) where qo is the probability that the transmitted symbol will be off the list of L*. The ordering distribution {q1} will depend upon EJN1 and the jamming format encountered, which we shall examine next. Suppose that a tone jammer divides his power, J, equally SO as to jam a fraction p of the total number of hopping frequencies. Furthermore, suppose that the jammer has perfect knowledge of the communicator's frequency slots and positions his tones randomly among these slots. Then, defining as the signal-to-jamming-tone power ratio, the number of slots that the jam- mer jams is N* = B(J/S). Denoting the time per bit by T6, the total number of hopping frequencies is NT = WSSTRR = R(W) = (E/N))(J/S), SO that B = p(EJN1) where SIJ < B < EJN1. Let Tx = 1 indicate that the symbol X was hit by the jammer (T = 0 otherwise), then the energy detector out- puts for the transmitted symbol, X, and any X # X are given by Tx=0 = (2.31) where O is the relative phase angle between the information and jamming tones. Letting NJ denote the number of MFSK symbols, other than X, hit by the jammer during a hop, then (2.32) where = First, consider the case where the information tone is not hit (Tx = 0). If B > 1, then X places first on the list. If B < 1, then X places (nj + 1)-th. However, sufficiently near = 1, the ordering of X and the NJ jammed sym- bols will be determined by noise sources not modelled here (e.g., receiver nosie). Consequently, at = 1, we assume that X can place anywhere among 9We define R = code rate in bits per MFSK chip, Rb = data rate in bits per second, N 1 = J/Wss, and the normalized cutoff rate ro = R/logM. Multiple Access NOISE L*=4. Figure 2.18. Minimum EIN for list detection (4 FSK). the NJ jammed tones with equal probability SO that - = SI,n+1; (2.33) Next, consider the case when X is hit by the jammer (Tx = 1). Assume that the relative phase angle, 0, is uniformly distributed over (-,. Notice from (2.33) that when 4,