Comparative study of indoor propagation model below and above 6 GHz for 5G wireless networks

It has been widely speculated that the performance of the next generation based wireless network should meet a transmission speed on the order of 1000 times more than the current cellular communication systems. The frequency bands above 6 GHz have received significant attention lately as a prospective band for next generation 5G systems. The propagation characteristics for 5G networks need to be fully understood for the 5G system design. This paper presents the channel propagation characteristics for a 5G system in line of sight (LOS) and non-LOS (NLOS) scenarios. The diffraction loss (DL) and frequency drop (FD) are investigated based on collected measurement data. Indoor measurement results obtained using a high-resolution channel sounder equipped with directional horn antennas at 3.5 GHz and 28 GHz as a comparative study of the two bands below and above 6 GHz. The parameters for path loss using different path loss models of single and multi-frequencies have been estimated. The excess delay, root mean square (RMS) delay spread and the power delay profile of received paths are analyzed. The results of the path loss models show that the path loss exponent (PLE) in this indoor environment is less than the free space path loss exponent for LOS scenario at both frequencies. Moreover, the PLE is not frequency dependent. The 3GPP path loss models for single and multi-frequency in LOS scenarios have good performance in terms of PLE that is as reliable as the physically-based models. Based on the proposed models, the diffraction loss at 28 GHz is approximately twice the diffraction loss at 3.5 GHz. The findings of the power delay profile and RMS delay spread indicate that these parameters are comparable for frequency bands below and above 6 GH

Computational Intelligence and Human- Computer Interaction: Modern Methods and Applications

The present book contains all of the articles that were accepted and published in the Special Issue of MDPI’s journal Mathematics titled "Computational Intelligence and Human–Computer Interaction: Modern Methods and Applications". This Special Issue covered a wide range of topics connected to the theory and application of different computational intelligence techniques to the domain of human–computer interaction, such as automatic speech recognition, speech processing and analysis, virtual reality, emotion-aware applications, digital storytelling, natural language processing, smart cars and devices, and online learning. We hope that this book will be interesting and useful for those working in various areas of artificial intelligence, human–computer interaction, and software engineering as well as for those who are interested in how these domains are connected in real-life situations

Antennas and beam-steering arrays for polarization diversity and full-duplex applications

This thesis presents new designs for polarization diverse dielectric resonator antennas (DRAs) as well as antennas that can offer efficient full-duplex (FD) functionality. Basically, this research effort has been completed to meet the demands of modern tracking systems as well as in-band full-duplex communication systems. For these applications antenna polarization control, compatibility, co-location, and isolation are the important parameters to support these high-performance systems. The first part of the thesis covers the challenges of modern radio frequency (RF) environments where the proposed polarization reconfigurable antennas are introduced. At first, a multi-port DRA is outlined as a possible candidate for the global positioning system (GPS) and the Global Navigation Satellite System (GNSS). To further advance this original design, and in an effort to reduce the size whilst maintaining polarization control, an integrated circuit was also proposed and tested. Advancing from the research work of phase polarization control using DRAs, the second part of the thesis studies other new antennas which are suitable for FD communications. Those antennas offer high isolation which makes the signal recoverable for those FD systems. To advance the state-of-the-art, an H-shaped slot antenna arrangement with parasitic patches and dual-differential feeding was proposed. The antenna architecture was investigated with both external and integrated feed systems and both prototypes offer high isolation levels. The single-element was further integrated into a 1×4 antenna array which was shown to offer similar isolation levels and with the capability to beam steer. Further research included high isolation antennas for operation in the 5G mm-wave band. In particular, a new FD pattern reconfigurable antenna was proposed which can be used in dual-polarized radars and other FD systems. Depending on the input phase excitation, the beam pattern control can be established with sum or difference patterns or both. Also, the antenna concept was further extended into a novel FD antenna array. This array has a similar common and/or differential feeding which can provide sum or difference patterns in the far-field. Also, an external Butler matrix was used to investigate the beam-steering capabilities of the array. These antenna systems also have applications for dual-polarized radars, retro-directive arrays, and other beam-tracking scenarios which require high inter-port isolation.James Watt Scholarshi