### Browsing by Subject "Average probability of error"

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Item Open Access Detector randomization and stochastic signaling for minimum probability of error receivers(Institute of Electrical and Electronics Engineers, 2012) Dulek, B.; Gezici, SinanShow more Optimal receiver design is studied for a communications system in which both detector randomization and stochastic signaling can be performed. First, it is proven that stochastic signaling without detector randomization cannot achieve a smaller average probability of error than detector randomization with deterministic signaling for the same average power constraint and noise statistics. Then, it is shown that the optimal receiver design results in a randomization between at most two maximum a-posteriori probability (MAP) detectors corresponding to two deterministic signal vectors. Numerical examples are provided to explain the results.Show more Item Open Access Effects of signal randomization on performance of binary communications systems(IEEE, 2010) Göken, Çağrı; Gezici, Sinan; Arıkan, OrhanShow more In this paper, effects of signal randomization are studied for binary communications systems. First, it is stated that the average probability of error for a power-constrained binary communications system is minimized when each symbol is randomized between at most two signal values. Then, a fixed detector is considered, and sufficient conditions under which its performance can or cannot be improved via signal randomization are presented. After that, the joint design of detectors and signal structures is studied, and an optimization problem is formulated to determine the optimal system parameters. Finally, numerical results are presented to exemplify the improvements via signal randomization. ©2010 IEEE.Show more Item Open Access Optimal channel switching in the presence of stochastic signaling(IEEE, 2013) Dulek, B.; Varshney P.K.; Tutay, Mehmet Emin; Gezici, SinanShow more Optimal channel switching and detector design is studied for M-ary communication systems in the presence of stochastic signaling, which facilitates randomization of signal values transmitted for each information symbol. Considering the presence of multiple additive noise channels (which can have non-Gaussian distributions in general) between a transmitter and a receiver, the joint optimization of the channel switching (timesharing) strategy, stochastic signals, and detectors is performed in order to achieve the minimum average probability of error. It is proved that the optimal solution to this problem corresponds to either (i) switching between at most two channels with deterministic signaling over each channel, or (ii) time-sharing between at most two different signals over a single channel (i.e., stochastic signaling over a single channel). For both cases, the optimal solutions are shown to employ corresponding maximum a posteriori probability (MAP) detectors at the receiver. Numerical results are presented to investigate the proposed approach. © 2013 IEEE.Show more Item Open Access Optimal detector randomization in cognitive radio systems in the presence of imperfect sensing decisions(2014) Sezer, A. D.; Gezici, Sinan; Gursoy, M. C.Show more In this study, optimal detector randomization is developed for secondary users in a cognitive radio system in the presence of imperfect spectrum sensing decisions. It is shown that the minimum average probability of error can be achieved by employing no more than four maximum a-posteriori probability (MAP) detectors at the secondary receiver. Optimal MAP detectors and generic expressions for their average probability of error are derived in the presence of possible sensing errors. Also, sufficient conditions are presented related to improvements due to optimal detector randomization.Show more Item Open Access Stochastic signaling under second and fourth moment constraints(IEEE, 2010) Göken, Çağrı; Gezici, Sinan; Arıkan, OrhanShow more Stochastic signaling is investigated under second and fourth moment constraints for the detection of scalar-valued binary signals in additive noise channels. Sufficient conditions are derived to determine when the use of stochastic signals instead of deterministic ones can or cannot enhance the error performance of a given binary communications system. Also, a convex relaxation approach is employed to obtain approximate solutions of the optimal stochastic signaling problem. Finally, numerical examples are presented, and extensions of the results to M-ary communications systems and to other criteria than the average probability of error are discussed.Show more Item Open Access A survey on optimal stochastic signaling and detector randomization(IEEE, 2011) Dülek, Berkan; Göken, Çağrı; Gezici, Sinan; Arıkan, OrhanShow more In this paper, a survey on stochastic signaling and detector randomization is presented for average power-constrained binary communications systems. First, the case of a single fixed detector at the receiver is considered, and then the joint design of detector and optimal signaling is studied. In addition, the optimal receiver design is examined in the presence of detector randomization and stochastic signaling. It is observed that the average probability of error achieved via detector randomization cannot be larger than that achieved via stochastic signaling in the presence of optimal MAP detectors. Finally, a numerical study is presented to illustrate an example.Show more