Performance evaluation of AF-relayed mixed FSO/mm-wave-RF link modeled by generalized misalignment and RF fading distributions

The performance of a generalized mixed free-space-optical (FSO)/millimeter (mm)-wave radio-frequency (RF) two-hop link model is investigated in this work. The first-hop FSO channel considers the influence of path loss, atmospheric turbulence which is modeled by the gamma–gamma (GG)-distribution, and generalized misalignment errors which incorporate the effects of non-zero boresight errors, different jitter standard deviations along the horizontal and vertical directions, and correlation between the horizontal and vertical displacements. The second-hop RF link is modeled by an extended-generalized-K (EGK) distribution which is a versatile distribution and can characterize various fading conditions in mm-wave wireless channels where the transmission frequency is in excess of 60 GHz, and considers non-homogeneous propagation, interference effects due to multiuser transmission, multipath fading and shadowing effects observed in mm-wave RF wireless channels. The considered system employs fixed-gain amplify-and-forward (AF) relay-assisted transmission. The statistical characteristic for the end-to-end SNR, i.e., cumulative distribution function (cdf), is obtained for the considered system model in this work. Based on the obtained result for cdf, the outage and error performance is evaluated, and closed form expressions for the same are derived. The derived analytical results have been illustrated through numerical plots.

3D Antenna Structures Using Uniform Triangular Arrays for Efficient Full-Directional Multiuser Transmission

In order to increase the system capacity of the 5G mobile communication system, multiple-input multiple-output (MIMO) transmission techniques using a large-scale array over the millimeter-wave band have attracted a great amount of attention. To cope with various types of receivers expected in 5G communications such as user equipment (UE) in small cells, indoor Internet-of-Things (IoT) devices at diverse locations, and drones performing aerial navigation, newer types of antenna arrays require all-directional transmission capability. Existing antenna structures with typical panel arrays, however, have restrictions on their transmission angles in both horizontal and vertical directions. In this paper, we propose to employ three-dimensional (3D) array structures composed of multiple triangular panels for efficient massive MIMO transmission of the next-generation wireless systems. We analyze beamforming characteristics of a uniform triangular array (UTA) suitable for such 3D array configurations and present a basic codebook applicable to UTAs. Using antenna structures with multiple UTA panels, multiuser transmission performance is evaluated to demonstrate the effectiveness of the proposal.

FPAA Implementation of Chaotic Modulation Based on Nahrain Map

Due to characteristic of chaotic systems in terms of nonlinearity, sensitivity to initial values, and non-periodicity, they are used in many applications like security and multiuser transmission. Nahrain chaotic map is an example of such systems that are recently proposed with excellent features for the use in multimedia security applications. Although the implementation of chaotic systems is easy using low costanalogue ICs, this approach does not provide the flexibility that the reconfigurable analogue devices have in design possibilities such as reducing the complexity of design, real-time modification, software control and adjustment within the system. This paper presents a description of data modulation and demodulation based on Nahrain chaotic system and there hardware implementation using field programmable analogue array (FPAA) device. AN231E04 dpASP board is used as a target device for the implementation. The simulation results of system closely matched the programmable hardware testing results.