In spectrum-sharing systems where the secondary user (SU) opportunistically accesses the primary user (PU)’s licensed channel, the SU should satisfy both the transmit power constraint of the SU transmitter and the received power constraint at the PU receiver. This letter studies the ergodic capacity of spectrum-sharing systems in fading channels. The ergodic capacity expression along with the o...

This paper proposes novel satellite-based wireless sensor networks (WSNs), which integrate the WSN with the cognitive satellite terrestrial network. Having the ability to provide seamless network access and alleviate the spectrum scarcity, cognitive satellite terrestrial networks are considered as a promising candidate for future wireless networks with emerging requirements of ubiquitous broadb...

by Mostafa Khoshnevisan It is known that adaptive power and rate allocation is a useful technique for combating channel variations induced by multipath fading in wireless systems. We consider several fading channel models for which we aim to optimize a performance metric subject to various power and energy constraints. First, we find the general structure of optimal or suboptimal power policies...

Optimal power allocation for multiple-input multiple-output radar waveform design subject to combined peak and sum power constraints using two different criteria is addressed in this paper. The first one is by maximizing the mutual information between the random target impulse response and the reflected waveforms, and the second one is by minimizing the mean square error in estimating the targe...

A new upper bound on the capacity of powerand bandwidth-constrained optical wireless links over gamma-gamma atmospheric turbulence channels with intensity modulation and direct detection is derived when on-off keying (OOK) formats are used. In this free-space optical (FSO) scenario, unlike previous capacity bounds derived from the classic capacity of the well-known additive white Gaussian noise...

This paper investigates the discrete-time per-sample model of the zero-dispersion optical fiber. It is shown that the capacityachieving input distribution is unique, has (continuous) uniform phase and discrete amplitude with a finite number of mass points. The optimality of this multi-ring input holds when the channel is subject to general input cost constraints that include peak power constrai...

Abstruct-The capacity C(p,, p p ) of the discrete-time quadrature additive Gaussian channel (QAGC) with inputs subjected to (normalized) average and peak power constraints, pa and pp respectively, is considered. By generalizing Smith’s results for the scalar average and peak-power-constrained Gaussian channel, it is shown that the capacity achieving distribution is discrete in amplitude (envelo...

We study the information rates of unipolar orthogonal frequency division multiplexing (OFDM) in discrete-time optical intensity channels (OIC) with Gaussian noise under average optical power constraint. Several single-, double-, and multicomponent unipolar OFDM schemes are considered under the assumption that independent and identically distributed (i.i.d.) Gaussian or complex Gaussian codebook...

Large-scale MIMO systems have been considered as one of the possible candidates for the next-generation wireless communication technique, due to their potential to provide significant higher throughput than conventional wireless systems. For such systems, Zero-Forcing (ZF) and Conjugate Beamforming (CB) precoding have been considered as two possible practical spatial multiplexing techniques, an...