6 research outputs found
MIMO CDMA-based Optical SATCOMs: A New Solution
A new scheme for MIMO CDMA-based optical satellite communications (OSATCOMs)
is presented. Three independent problems are described for up-link and down-
link in terms of two distinguished optimization problems. At first, in up-link,
Pulse-width optimization is proposed to reduce dispersions over fibers as the
terrestrial part. This is performed for return-to-zero (RZ) modulation that is
supposed to be used as an example in here. This is carried out by solving the
first optimization problem, while minimizing the probability of overlapping for
the Gaussian pulses that are used to produce RZ. Some constraints are assumed
such as a threshold for the peak-to-average power ratio (PAPR). In down-link,
the second and the third problems are discussed as follows, jointly as a
closed-form solution. Solving the second optimization problem, an objective
function is obtained, namely the MIMO CDMA-based satellite weight-matrix as a
conventional adaptive beam-former. The Satellite link is stablished over flat
un-correlated Nakagami-m/Suzuki fading channels as the second problem. On the
other hand, the mentioned optimization problem is robustly solved as the third
important problem, while considering inter-cell interferences in the multi-cell
scenario. Robust solution is performed due to the partial knowledge of each
cell from the others in which the link capacity is maximized. Analytical
results are conducted to investigate the merit of system.Comment: IEEE PCITC 2015 (15-17 Oct, India
Dynamics Spectrum Sharing Environment Using Deep Learning Techniques
The recent fast expansion of mobile communication services has resulted in a scarcity of spectrum resources. The challenge of multidimensional resource allocation in cognitive radio systems is addressed in this work. Complicated and dynamic Spectrum Sharing SS systems might be vulnerable to a variety of possible security and privacy vulnerabilities, necessitating protection techniques that are adaptable, dependable, and scalable. Methods based on machine learning (ML) have repeatedly been proposed to overcome these challenges. We present a complete assessment of the current progress of ML-based SS approaches, the most crucial security challenges, and the accompanying protection mechanisms in this paper. We develop cutting-edge methodologies for improving the performance of SS communication systems in a variety of critical areas, such as ML-based cognitive radio networks (CRNs), ML-based database assisted SS networks, ML-based LTE-U networks, ML-based ambient backscatter networks, and other ML-based SS solutions. The results of the simulation trials show that the suggested strategy may successfully boost the user's incentive while reducing collisions. In terms of reward, the suggested strategy beats opportunistic multichannel ALOHA by around 10% and 30%, respectively, for the single SU and multi-SU scenarios. 
Hybrid Transceiver Optimization for Multi-Hop Communications
Multi-hop communication with the aid of large-scale antenna arrays will play
a vital role in future emergence communication systems. In this paper, we
investigate amplify-and-forward based and multiple-input multiple-output
assisted multi-hop communication, in which all nodes employ hybrid
transceivers. Moreover, channel errors are taken into account in our hybrid
transceiver design. Based on the matrix-monotonic optimization framework, the
optimal structures of the robust hybrid transceivers are derived. By utilizing
these optimal structures, the optimizations of analog transceivers and digital
transceivers can be separated without loss of optimality. This fact greatly
simplifies the joint optimization of analog and digital transceivers. Since the
optimization of analog transceivers under unit-modulus constraints is
non-convex, a projection type algorithm is proposed for analog transceiver
optimization to overcome this difficulty. Based on the derived analog
transceivers, the optimal digital transceivers can then be derived using
matrix-monotonic optimization. Numeral results obtained demonstrate the
performance advantages of the proposed hybrid transceiver designs over other
existing solutions.Comment: 32 pages, 6 figures. This manuscript has been submitted to IEEE
Journal on Selected Areas in Communications (special issue on Multiple
Antenna Technologies for Beyond 5G