Lower Bound on the Ensemble Average Error Probability in a Multiple Access Channel

Developing the methods of [R. G. Gallager, IEEE Trans. Inf. Theory, 1973, vol. 19, no. 22, pp. 244–246; A. G. D'yachkov, Probl. Peredachi Inf., 1980, vol. 16, no. 2, pp. 18–24; 1979, vol. 15, no. 2, pp. 23–35; A. G. D'yachkov and G. Sh. Poltyrev, Probl. Upravl. Teor. Inf., 1982, vol. 11, no. 5, pp. 365–372], we construct a lower asymptotic bound on the ensemble error probability of maximum likelihood decoding for a multiple access channel. This bound allows us to find a range of rates where the known upper bound [H. Liao, PhD Thesis, Univ. of Hawaii, 1972] is asymptotically tight.