 ratio is again given by (2.2), where the processing gain is the total spread- spectrum bandwidth divided by the link data rate in bits per second. Figure 2.9 again illustrates the special case where all L interference signals have the same power at the receiver. The only difference betwen using Figure 2.9 for the DS/BPSK system and the FH/MFSK system is the choice for the required bit energy-to-noise ratio y to be used. For DS/BPSK this is based on the additive white Gaussian noise channel, whereas for FH/MFSK sys- tems it is based on the worst case multitone jammer. The multitone jammer analysis of Chapter 2 in Part 2 assumes ideal jam- mer state information and conventional chip energy detector outputs. What this means is that during a hop time interval, in the MFSK sub-band of the intended transmitted signal, the receiver has M energy detectors. If a jam- ming tone is also present along with the transmitted signal in this sub-band, then this fact is used by the receiver when it takes a weighted sum of energy detector outputs to make decisions. If this same type of receiver is used in the radio network with interference due to other radios, the resulting required bit energy-to-noise ratio y would be less than that for the worst case multitone jammer. The number of users L in Figure 2.9 would then be a Spread-Spectrum Multiple Access with FH/MFSK Waveforms lower bound when the required value of Y is taken from the worst case mul- titone jamming analysis. With FH/MFSK waveforms many other detectors and metrics are possi- ble. Against intelligent jammers, combining chip energies without jammer state information is not effective. This is because such a pure "soft decision" receiver without jammer state information is vulnerable to a jammer strat- egy where high jammer power can be concentrated on a small number of symbols of a coded transmission sequence and lead to a large number of decoding errors. One approach to alleviating this problem is to quantize the chip energy detector outputs into a finite number of th