48 citations · 296 across the 40 of their papers we have counts for
42 papers · 1 filter
Optimal Power Assignment for MIMO Channels Under Joint Total and Per-Group Power Constraints
Mahdi Khojastehnia, Ioannis Lambadaris, Ramy H Gohary +1
In this paper we consider a communication system with one transmitter and one receiver. The transmit antennas are partitioned into disjoint groups, and each group must satisfy an a…
Structural Design of Non-Uniform Linear Arrays for Favorable Propagation in Massive MIMO
E. Anarakifirooz, S. Loyka
Favorable propagation (FP) for massive multiple-input multiple-output (MIMO) systems with uniform and non-uniform linear arrays is considered. A gap in the existing FP studies of u…
The Secrecy Capacity of The Gaussian Wiretap Channel with Rate-Limited Help
Sergey Loyka, Neri Merhav
The Gaussian wiretap channel with rate-limited help, available at the legitimate receiver (Rx) or/and transmitter (Tx), is studied under various channel configurations (degraded, r…
On the Capacity of Gaussian MIMO Channels with Memory
Sergey Loyka, Charalambos D. Charalambous
The operational capacity of Gaussian MIMO channels with memory was obtained by Brandenburg and Wyner in [9] under certain mild assumptions on the channel impulse response and its n…
Favorable Propagation for Massive MIMO with Circular and Cylindrical Antenna Arrays
Elham Anarakifirooz, Sergey Loyka
Massive MIMO systems with uniform circular and cylindrical antenna arrays are studied. Favorable propagation property is rigorously shown to hold asymptotically in LOS environment…
Simple Closed-Form Approximations for Achievable Information Rates of Coded Modulation Systems
Maria Urlea, Sergey Loyka
The intuitive sphere-packing argument is used to obtain analytically-tractable closed-form approximations for achievable information rates of coded modulation transmission systems,…
Comments on "Precoding and Artificial Noise Design for Cognitive MIMOME Wiretap Channels"
Mahdi Khojastehnia, Sergey Loyka
Several gaps and errors in [1] are identified and corrected. While accommodating these corrections, a rigours proof is given that the successive convex approximation algorithm in […
Algorithms for Globally-Optimal Secure Signaling over Gaussian MIMO Wiretap Channels Under Interference Constraints
Limeng Dong, Sergey Loyka, Yong Li
Multi-user Gaussian MIMO wiretap channel is considered under interference power constraints (IPC), in addition to the total transmit power constraint (TPC). Algorithms for \textit{…
On The Capacity of Gaussian MIMO Channels Under Interference Constraints (full version)
Sergey Loyka
Gaussian MIMO channel under total transmit and multiple interference power constraints (TPC and IPCs) is considered. A closed-form solution for its optimal transmit covariance matr…
Optimal Location of Cellular Base Station via Convex Optimization
Elham Kalantari, Sergey Loyka, Halim Yanikomeroglu +1
An optimal base station (BS) location depends on the traffic (user) distribution, propagation pathloss and many system parameters, which renders its analytical study difficult so t…
The Capacity and Optimal Signaling for Gaussian MIMO Channels Under Interference Constraints (full version)
Sergey Loyka
Gaussian MIMO channel under total transmit and interference power constraints (TPC and IPC) is considered. A closed-form solution for the optimal transmit covariance matrix in the…
Comments on "On Favorable Propagation in Massive MIMO Systems and Different Antenna Configurations" [1]
S. Loyka, M. Khojastehnia
It is shown that the condition of Theorem 1 in [1] never holds in practice and that Theorem 2 is incorrect under the stated condition. Extra assumptions or/and modifications are ne…
Time-Invariant Feedback Strategies Do Not Increase Capacity of AGN Channels Driven by Stable and Certain Unstable Autoregressive Noise
Charalambos D. Charalambous, Christos Kourtellaris, Sergey Loyka
The capacity of additive Gaussian noise (AGN) channels, , , with time-inva…
On The Capacity of Gaussian MIMO Channels Under The Joint Power Constraints
Sergey Loyka
The capacity and optimal signaling over a fixed Gaussian MIMO channel are considered under the joint total and per-antenna power constraints (TPC and PAC). While the general case r…
Feedback Does Not Increase the Capacity of Compound Channels with Additive Noise
Sergey Loyka, Charalambos D. Charalambous
A discrete compound channel with memory is considered, where no stationarity, ergodicity or information stability is required, and where the uncertainty set can be arbitrary. When…
The Capacity of Gaussian MIMO Channels Under Total and Per-Antenna Power Constraints
S. Loyka
The capacity of a fixed Gaussian multiple-input multiple-output (MIMO) channel and the optimal transmission strategy under the total power (TP) constraint and full channel state in…
Optimal Signaling for Secure Communications over Gaussian MIMO Wiretap Channels
Sergey Loyka, Charalambos D. Charalambous
Optimal signalling over the Gaussian MIMO wire-tap channel is studied under the total transmit power constraint. A closed-form solution for an optimal transmit covariance matrix is…
Rank-Deficient Solutions for Optimal Signaling over Wiretap MIMO Channels
Sergey Loyka, Charalambos D. Charalambous
Capacity-achieving signaling strategies for the Gaussian wiretap MIMO channel are investigated without the degradedness assumption. In addition to known solutions, a number of new…
A General Formula for Compound Channel Capacity
Sergey Loyka, Charalambos D. Charalambous
A general formula for the capacity of arbitrary compound channels with the receiver channel state information is obtained using the information density approach. No assumptions of…
Capacity Achieving Distributions & Information Lossless Randomized Strategies for Feedback Channels with Memory: The LQG Theory of Directed Information-Part II
Charalambos D. Charalambous, Christos K. Kourtellaris, Sergey Loyka
A methodology is developed to realized optimal channel input conditional distributions, which maximize the finite-time horizon directed information, for channels with memory and fe…
Optimal Estimation via Nonanticipative Rate Distortion Function and Applications to Time-Varying Gauss-Markov Processes
Photios A. Stavrou, Themistoklis Charalambous, Charalambos D. Charalambous +1
In this paper, we develop {finite-time horizon} causal filters using the nonanticipative rate distortion theory. We apply the {developed} theory to {design optimal filters for} tim…
The Secrecy Capacity of Compound Gaussian MIMO Wiretap Channels
Rafael F. Schaefer, Sergey Loyka
Strong secrecy capacity of compound wiretap channels is studied. The known lower bounds for the secrecy capacity of compound finite-state memoryless channels under discrete alphabe…
An Algorithm for Global Maximization of Secrecy Rates in Gaussian MIMO Wiretap Channels
Sergey Loyka, Charalambos D. Charalambous
Optimal signaling for secrecy rate maximization in Gaussian MIMO wiretap channels is considered. While this channel has attracted a significant attention recently and a number of r…
On Convexity of Error Rates in Digital Communications
Sergey Loyka, Victoria Kostina, Francois Gagnon
Convexity properties of error rates of a class of decoders, including the ML/min-distance one as a special case, are studied for arbitrary constellations, bit mapping and coding. E…