- ples also show that the optimum maximum-likelihood receiver can achieve the same performance as the single radio transmitter case for high signal-to-noise ratios. At high signal-to-noise ratios the optimum maximuum-likelihood receiver in these examples can reliably determine the transmitted data from all simul- taneously transmitting radios. This is not surprising since we assumed com- plete information about the signal parameters {A1}, {TI}, and {01}. Also we assumed no quantization of the matched filter output samples {yk} or of the metrics used in the Viterbi algorithm. In practice some quantized metrics must be used and little or no side information may be available regarding signal parameters. The optimum receiver results presented here serve as a theoretically achievable limit or baseline with which we can compare prac- tical uncoded systems. 2.4 SPREAD-SPECTRUM MULTIPLE ACCESS WITH FH/MFSK WAVEFORMS SSMA systems using FH/MFSK waveforms can take a wider range of forms compared with systems using DS/BPSK waveforms. This is due to the fact that a wide variety of detector functions and decoder metrics can be used here including metrics that allow for side information regarding the chan- nel conditions (see Chapter 2, Part 2). In addition, with FH/MFSK wave- forms, M is a parameter which can be increased until the entire spread-spectrum frequency band consists of one large MFSK signalling band with no hopping. For point-to-point communication we exploit the fact that interference due to other radio signals resembles multitone jamming. In general worst case multitone jamming with the same total interference power will result in greater performance degradation than this unintentional interference due to other FH/MFSK signals. Therefore, earlier results on multitone jamming can be used to upper bound bit error probabilities in the FH/MFSK SSMA system. For point-to-multipoint SSMA with FH/MFSK waveforms there exists the possibility of considering synchronous radio transmitters. In practice, with FH/MFSK waveforms