slots are independently jammed with the same probability. In fact, the independence assumption is not always justified. Conditioned on one FH slot being jammed, another given slot is jammed with probability (Q - 1)/(N, - 1), which is essentially equal to p in (2.26) implying independent, equally likely jamming of both slots pro- vided N Q >> 1. Since our performance analysis focusses on the dehopped M-ary band containing the transmitted data symbol, we can assume that each of the M slots in that band is independently tone jammed with probability p by extending the provision above to V,=QM-1. (2.29) Under this assumption, u=1-(1-p) (2.30) which reduces to the value of for n = band multitone jamming when p is small; this suggests that these two strategies may be equally effective for p << 1. Worst Case Jamming 2.2.2.1 Random Jamming Tone Phase For all of the multitone strategies under consideration, there is the possibility that a given MFSK received signal will itself be jammed. When this occurs, the relative phase of the data and jamming tones impacts the energy detec- tor output for that frequency, a factor first analyzed by Trumpis [7, pp. 15- 16]. We have already assumed that there is no frequency offset between the data and jamming tones. We now additionally assume that the phase differ- ence is uniformly distributed over [0, 2). The received signal power is S: denote the received power in each jam- ming tone by (2.31) where a is a parameter to be optimized by the jammer. Then a received data signal which has been tone jammed has the composite form 2S sin = (2.32) where the phasor representation of (2.32) in Figure 2.11 indicates that the total resultant power is (2.33) The energy detector output for that M-ary symbol (or chip, in the uncoded case) is (2.34) where the symbol (chip) energy E = SIR = SIR. Table 2.2 extends (2.34) to the other three cases required to determine the system performance with multitone jamming in the absence of thermal noise. 2.s sin 2/S 25 cos Figure 2.11. Phasor representation of t