Tauste Campo, Adrià, 1982-Guillén i Fábregas, A. (Albert)Biglieri, Ezio2018-11-122018-11-122009Tauste Campo A, Guillén i Fàbregas A, Biglieri E. High-SNR analysis of optimum multiuser detection with an unknown number os users. In: 2009 IEEE Information Theory Workshop (ITW '09); 2009 Oct 11-16; Taormina, Italy. New York: IEEE, 2009. p. 283-7. DOI: 10.1109/ITW.2009.5351171978-1-4244-4982-8http://hdl.handle.net/10230/35728Comunicació presentada al 2009 IEEE Information Theory Workshop celebrat a Taormina (Itàlia) de l'11 al 16 d'octubre de 2009.We analyze multiuser detection under the assumption that the number of users accessing the channel is unknown by the receiver. Our main goal is to determine the performance loss caused by the need for estimating the identities of active users, which are not known a priori. To prevent a loss of optimality, we assume that identities and data are estimated jointly, rather than in two separate steps. We examine the performance of multiuser detectors when the number of potential users is large. Statistical-physics methodologies are used to determine the fixed-point equation whose solutions yield the multiuser efficiency of the optimal detector. Special attention is paid to the large signal-to-noise ratio, which yields tight closed-form bounds on the minimum mean-squared error. These bounds analytically illustrate the set of solutions of the fixed-point equation, and their relationship with the maximum system load. By identifying the region of computationally feasible solutions, we study the maximum load that the detector can support for a given SNR and quality of service, specified by the multiuser efficiency.application/pdfeng© 2009 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising or promotional purposes, creating new collective works, for resale or redistribution to servers or lists, or reuse of any copyrighted component of this work in other works. The final published article can be found at http://ieeexplore.ieee.org/xpl/articleDetails.jsp?arnumber=5351171info:eu-repo/semantics/conferenceObjecthttp://dx.doi.org/10.1109/ITW.2009.5351171info:eu-repo/semantics/openAccess