Published in Viswanathan, R., & Gupta, S. (1983). Performance comparison of likelihood, hard-limited, and linear combining receivers for FH-MFSK mobile radio--Base-to-mobile transmission. IEEE Transactions on Communications, 31(5), 670-677. ©1983 IEEE. Personal use of this material is permitted. However, permission to reprint/republish this material for advertising or promotional purposes or for creating new collective works for resale or redistribution to servers or lists, or to reuse any copyrighted component of this work in other works must be obtained from the IEEE. This material is presented to ensure timely dissemination of scholarly and technical work. Copyright and all rights therein are retained by authors or by other copyright holders. All persons copying this information are expected to adhere to the terms and constraints invoked by each author's copyright. In most cases, these works may not be reposted without the explicit permission of the copyright holder.


The performances of three receivers, namely, the hard-limited, the linear, and the maximum-likelihood combiners for the detection of frequency-hopped multilevel frequency-shift keyed signals transmitted from mobiles to base have been reported earlier [11]. Only the hard-limited combiner has been analyzed with respect to base-to-mobile link [1]. Here, we give new results on the performance of the likelihood and the linear combining receivers operating at the mobiles. Whereas it is possible to find exactly the union bound on the probability of hit error for a linear combiner, for a likelihood receiver, bounding and approximation techniques such as simple Chernoff bound and saddle point integration were employed. We also observe the asymptotic (SNR → ∞) equivalence of the hard-limited and the likelihood receivers. This, together with the approximate error estimates at finite SNR, leads us to believe that the likelihood receiver is only marginally superior to a hard-limited combiner. As expected, the linear combiner performs poorly.