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This correspondence highlights the performance limitation of linear minimum mean-squared error (mmse) detection in underdetermined vector Gaussian channels (as in overloaded code-division multiple-access (CDMA) systems) where the number of symbols (users) exceeds the signal space dimension (spread factor). It is shown that for such a simple receiver it is(More)
—Three noncoherent minimum mean-squared error (MMSE)-based multiuser receivers are proposed for multipulse modulation. These receivers have a common MMSE prefilter and are followed by one of three phase-independent decision rules. The simplest decision rule selects the maximum magnitude of the MMSE filter outputs, and the other two account for the(More)
Multiuser detection for overloaded code-division multiple-access (CDMA) systems, in which the number of users is larger than the dimension of the signal space, is of particular interest when bandwidth is at a premium. In this paper, certain fundamental questions are answered regarding the asymptotic forms and performance of suboptimum multiuser detectors(More)
This document contains a first assessment of spatial transmission schemes regarding performance and complexity. In order to assess advanced beamforming and MIMO technologies, mathematical models, as well as methodologies for simulation and assessment have been developed. Conceptual work and simulation campaigns have been conducted. A baseline WINNER(More)
— Noncoherent minimum mean-squared error (MMSE)-based multiuser receivers are proposed for nonorthogonal multipulse modulation. The three proposed receivers have a common MMSE pre-filter and are followed by one of three distinct noncoherent decision rules. The simplest decision rule selects the maximum magnitude of the MMSE filter outputs and the other two(More)
This correspondence characterizes the performance limitation of the well-acclaimed generalized Welch-bound equality (WBE) signals under linear minimum mean-squared error (MMSE) detection. It is analytically proven, and experimentally verified, that when users in an overloaded but finite-size code-division multiple-access (CDMA) system are allocated such(More)
— This paper addresses signal optimization for CDMA systems under linear minimum mean-squared error (MMSE) detection. In particular, generalized Welch-bound equality (WBE) signals, which have been found to be optimum for various measures/problems, are studied from a new perspective. Specifically, we consider the asymptotic effective energy (AEE) criterion(More)
— The problem of signal design for bandwidth efficient multiple access is addressed under quality of service (QoS) constraints specified by (possibly different) BER. Indeed, BER more accurately measures the performance than the signal-to-interference ratio (SIR) for uncoded communication. Furthermore, we argue that the asymptotic effective energy (AEE)(More)