The presence of multiple users in a network provides us with a valuable resource known as multiuser diversity. With information on the instantaneous states of the channels, multiuser diversity can be tapped by opportunistic multiuser scheduling. It is important that the channel state information is acquired in a cost-effective way so that the losses involved in this operation do not offset the ...

This paper introduces the problem of noncoherent detection for nonorthogonal multipulse modulation in the context of the synchronous multiuser Gaussian channel. Each user sends an M -ary information symbol by transmitting one ofM possibly nonorthogonal waveforms. Furthermore, the M signals of one user are allowed to be correlated with the signals of all other users. A key idea proposed here is ...

In many wireless systems where multiuser detection techniques may be applied, the ambient channel noise is known through experimental measurements to be decidedly nonGaussian, due largely to impulsive phenomena. The performance of many multiuser detectors can degrade substantially in the presence of such impulsive ambient noise. In this paper, we develop robust multiuser detection techniques fo...

Drastic improvements in transmission rate and system capacity are required towards 5th generation mobile communications (5G). One promising approach, utilizing the millimeter wave band for its rich spectrum resources, suffers area coverage shortfalls due to its large propagation loss. Fortunately, massive multiple-input multiple-output (MIMO) can offset this shortfall as well as offer high orde...

Both linear and nonlinear transmit precoding strategies based on accurate channel state information (CSI) can significantly increase available throughput in a multiuser wireless system. With propagation delay, infrequent channel updates, lag due to network layer overhead, and time-varying node position or environment characteristics, channel knowledge becomes outdated and CSI-based transmission...

In wireless communication, the performance of network highly relies on accuracy channel state information (CSI). On other hand, statistics are usually unknown, and measurement is lost due to fading phenomenon. Therefore, we propose a estimation approach for downlink communication under uncertainty. We apply Tobit Kalman filter (TKF) method estimate hidden vectors channels. To minimize maximum e...

In CDMA, the optimal multiuser detector in mean square sense is the conditional mean estimator (CME) regardless of the input distribution, which outputs the expected value of the transmitted symbols conditioned on the received signal and the channel state (spreading sequences, fading, etc). In this paper, we first note that every multiuser detector can be reformulated as the CME for a certain p...

This paper studies multiuser orthogonal frequency division multiplexing (OFDM) system using adaptive subchannel and power allocation with partial channel information. Previous research on multiuser OFDM includes margin adaptive (MA) optimization and rate adaptive (RA) optimization. The capacity gain using adaptive resource allocation over fixed resource allocation such as time division multiple...

We consider a multiple antenna broadcast channel in which a base station equipped with M transmit antennas communicates with K ≥ M single-antenna receivers. Each receiver has perfect channel state information (CSI), whereas the transmitter has partial channel knowledge obtained via a limited rate feedback channel. Built upon multiuser interference bounds, we propose scalar feedback metrics that...

Multiuser detection for space-time coded synchronous multiple-access systems in the presence of independent Rayleigh fading is considered. Under the assumption of quasi-static fading, it is shown that optimal (full diversity-achieving) space-time codes designed for single-user channels, can still provide full diversity in the multiuser channel. The joint optimal maximum likelihood multiuser det...