A High-Order EMSIW MIMO Antenna for Space-Constrained 5G Smartphone

This paper proposes a high-order MIMO antenna operating at 3.5 GHz for a 5G new radio. Using an eighth-mode substrate integrated waveguide (EMSIW) cavity and considering a typical smartphone scenario, a two-element MIMO antenna is developed and extended to a twelve-element MIMO. These MIMO elements are closely spaced, and by employing multiple diversity techniques, high isolation is achieved without using a decoupling network. The asymmetric EMSIW structures resulted in radiation pattern diversity, and their orthogonal placement provides polarization diversity. The radiation characteristics and diversity performance are parametrically optimized for a two-element MIMO antenna. The experimental results exhibited 6.0 dB and 10.0 dB bandwidths of 250 and 100 MHz, respectively. The measured and simulated radiation patterns are closely matched with a peak gain of 3.4 dBi and isolation ≥36 dB. Encouraged with these results, higher-order MIMO, namely, four- and twelve-element MIMO are investigated, and isolation ≥35 and ≥22 dB are achieved, respectively. The channel capacity is found equal to 56.37 bps/Hz for twelve-element MIMO, which is nearly 6.25 times higher than the two-element counterpart. The hand and head proximity analysis reveal that the proposed antenna performances are within the acceptable limit. A detailed comparison with the previous works demonstrates that the proposed antenna offers a simple, low-cost, and compact MIMO antenna design solution with a high diversity performance.

An Alternative Statistical Characterization of TWDP Fading Model

Two-wave with diffuse power (TWDP) is one of the most promising models for the description of small-scale fading effects in 5G networks, which employs mmWave band, and in wireless sensor networks deployed in different cavity environments. However, its current statistical characterization has several fundamental issues. Primarily, conventional TWDP parameterization is not in accordance with the model’s underlying physical mechanisms. In addition, available TWDP expressions for PDF, CDF, and MGF are given either in integral or approximate forms, or as mathematically untractable closed-form expressions. Consequently, the existing TWDP statistical characterization does not allow accurate evaluation of system performance in all fading conditions for most modulation and diversity techniques. In this regard, physically justified TWDP parameterization is proposed and used for further calculations. Additionally, exact infinite-series PDF and CDF are introduced. Based on these expressions, the exact MGF of the SNR is derived in a form suitable for mathematical manipulations. The applicability of the proposed MGF for derivation of the exact average symbol error probability (ASEP) is demonstrated with the example of M-ary PSK modulation. The derived M-ary PSK ASEP expression is further simplified for large SNR values in order to obtain a closed-form asymptotic ASEP, which is shown to be applicable for SNR > 20 dB. All proposed expressions are verified by Monte Carlo simulation in a variety of TWDP fading conditions.

Time and Spatial Jitter Influence on the Performance of FSO Links with DF Relays and OC Diversity over Turbulence Channels

FSO communication is a viral technology among optical wireless communications, gathering the interest of both researchers and manufacturers. This is because of the many advantages associated with FSO communication, including high data rates, reliability, safety, and economy. However, there are several unavoidable drawbacks that shadow the performance of FSO systems. For example, atmospheric turbulence is a well-known problem related to the weather conditions of the channel, which causes the scintillation effect. Also, spatial jitter due to pointing errors is a critical factor of the link’s performance, caused by occasional misalignments between the transmitter and the receiver. Moreover, time jitter is another limiting agent that deteriorates the total throughput, inducing bit stream misdetections, caused by the arrival of out-of-sync pulses. All three effects have been exhaustively studied and many statistical models and interesting solutions have been proposed in the literature to estimate their magnitude and compensate for their impact. In this work, the turbulence effect was treated by Málaga distribution, the spatial jitter effect was regulated by the non-zero boresight model, and the time jitter effect was modeled by the generalized Gaussian distribution. Various modulation schemes were studied, along with DF multi-hop and optimal combining diversity techniques at the receiver’s end. New, accurate mathematical expressions of average BER performance have been obtained, and valuable conclusions were drawn thanks to the presented numerical results.

Investigation of 10-port coupled fed slotted MIMO antenna system for 5G mobile handset

A dual-band 10-port multiple input multiple output (MIMO) antenna array for 5G smartphone is proposed. Each antenna in the MIMO system can work from 3.4 to 3.6 GHz and 5 to 6 GHz with 10 dB (2:1 VSWR) impedance bandwidth. Nevertheless, for a 3:1 VSWR, the antenna operates from 3.3 to 3.8 GHz and 4.67 to 6.24 GHz. The MIMO system is formed by making 10 seven-shaped coupled fed slot antenna elements excited at two different resonant modes and integrated into the system circuit board. By implementing the spatial and polarization diversity techniques, high isolation better than 28 dB between any pair of antenna elements is achieved. The proposed 10-port MIMO antenna array is fabricated and measured. Significant radiation efficiency is obtained, ranging from 65 to 82% for both bands. The antenna gain in the required operating band is substantial, around 3–3.8 dBi. Further, the MIMO parameters such as envelope correlation co-efficient, channel capacity, and total active reflection co-efficient are calculated. The antenna's robustness is estimated by analyzing the user hand effects and specific absorption rate (SAR). The measured results are well agreed with the simulated results.

A Review of Multicultural Education in Northern Cyprus and Turkish Learning Levels of Students from Different Cultural Backgrounds

The purpose of this research is -within the frame of opinions by form teachers working in primary schools in Northern Cyprus- reviewing problems faced by the students coming from different cultural backgrounds and reviewing proposals to solve such problems, in addition to considering Turkish grades on foreign students’ report cards to determine Turkish learning levels of them. This study was carried out using a mix of qualitative and quantitative research methods as a base to understand the present situation. Within the scope of the purposeful sampling in the research, 40 classroom teachers from 5 primary schools from the Nicosia area were reached by using criterion sampling and maximum diversity techniques. A total of 120 foreign students were also reached. Open-ended questions were asked to teachers through semi-structured interview forms. The answers were interpreted by thematicizing. As a result of the study, problems faced by students from different cultures according to the opinions of teachers were grouped as; educational problems, communication problems, curriculum problems, problems related to family, and general problems. It is suggested to have special language programs for students from different cultural backgrounds.

Joint Source Channel Coding and Diversity Techniques for 3G/4G/LTE-A

There has been a tremendous growth in the joint source channel coding techniques of recent wireless communication system. The main objective of this technique is to simplify the architecture which eliminates the network errors and instability. This chapter mainly focuses on Joint Source Channel Coding (JSCC) in Multiple Input Multiple Output (MIMO) diversity to minimize the effects of noise, distortion and related phenomena for better reception of the signal with increased efficiency and spectrum utilization with link reliability. JSCC techniques in presence of 3G/4G/LTE-A for high data rate communication with the carrier aggregation is an important element for communication over wireless channel. In this chapter, the authors shall discuss the current state of research, the challenges related to the deployment of JSCC, the likely solutions and the usefulness as part of upcoming communication networks. A major part of the work shall focus on their suitability in LTE-A frameworks so essential for sustaining the current growth in wireless communication.