 for the evaluation of cutoff rates against worst case multitone jamming using the list detector. The metrics associated with list detector outputs are the maximum-likelihood metrics with or without jammer state information. Here jammer state information is in the form where the receiver knows which of the M frequencies contain some signal or interference energy. In the multiple access context we say that the receiver has "collision compen- Multiple Access sation" information since this is used to change or compensate the metric assigned to the list detector outputs. Our multiple access results are thus given for the cases with collision compensation (CC) and without collision compensation. For M-ary alphabets, the cutoff rate R can be defined by8 R0 = log2M - log2[1 + (M - 1)D] - (2.24) with the Chernoff parameter, D, given for X x x 1 by D = minE{expA[m(y,x)-m(y,x)]xsent} (2.25) where m(y,x) is the decision metric evaluated for the channel output, y, and the transmitted code symbol X. For MFSK, the channel output is the set of energy detector outputs y = (e1,e2,...,eM). The list decision metric is defined m(y,x)= NL (2.26) where Lx is the position on the list where the symbol x placed (symbol with the highest energy places first) and N is the "score" awarded to the symbol placing l-th on the list. For an arbitrary set of scores, N = (N , N2, NM), Ro is evaluted using (x x x), mne-{xl,ekxsent (2.27) where = lx sent}. Here we used the symmetry condition, for X # X, P{L& = k|xsent Lx = l} = (M - 1)-1(1-8l.k). (2.28) We can simplify the list metric by choosing to rank only the L* detector outputs with the highest energies. Each of the remaining M 2 L* unranked symbols would then be given a common score. This "list-of-L*" metric spe- cializes to the hard decision metric for L* = 1. By direct differentiation, we obtain conditions for selecting the list scores, N, SO as to maximize R for the list-of-L* metric (1 V The resulting list scores and cutoff rate are [111] k=1,2,...,L* (2.29) k = L* + 1,...,M 8A symmetric, me