PERFORMANCE ANALYSIS OF 5G AND BEYOND WIRELESS SYSTEMS

Abstract

With the recent advancements in wireless communication, there has been tremendous growth in the applications such as body area communication, vehicular communication and device-to-device (D2D) communication etc. In most of these future generation applications, the data is transferred from source to destination through a wireless link. The signal experience many phenomena like reflection, refraction, diffraction and scattering in its path traveling from transmitter (Tx) to receiver (Rx). These phenomena result in the fluctuations in the received signal strength which eventually degrades the quality of the signal and is termed as fading. Fading can be classified as small-scale fading and large-scale fading. To characterize the small-scale fading and large-scale fading, different mathematical models are used in literature. The size of the mobile cells in third/fourth generation (3G/4G) wireless technologies was relatively large, thus the signal propagation scenario was thought to be outdoor propagation and various models such as Rayleigh, Rician, Nakagami, Weibull etc. were used to model that scenario. One of the main objectives of the fifth generation (5G) wireless networks is to provide high throughput and low latency to all users anywhere within the coverage area. However, because of the high attenuation provided by the structures' walls, delivering reliable services to consumers inside the buildings remains a serious challenge. The creation of a heterogeneous cellular network, in which a macro-cell is overlaid over a number of femtocells, dedicated to providing coverage for indoor users, is an effective approach that has recently been embraced by numerous standards. Femtocells are small, vi low power cellular BS, which can be installed in a small business environment or a home to provide better coverage with improved battery life for the mobile stations. Due to the small areas of the femtocells, the characterization of the signal cannot be modeled in the form of traditional outdoor propagation models. For addressing the propagation phenomenon in 5G and beyond technology, Beaulieu-Xie (BX) and Fisher-Snedecor F (FSF) distributions are introduced. The BX fading channel has found application in the signal propagation in small buildings and fast-moving trains. FSF fading channel is a composite fading model that is used to model the signal propagation for D2D and wearable communication links. The performance of communication system inside the densely packed small cells or femtocells with maximum ratio combining (MRC) diversity is studied. The closed-form expressions for outage probability (Pout), amount of fading (AF) and average symbol error probability (ASEP) for coherent and non-coherent modulation schemes are derived for the said channel. Further, the channel capacity (CC) analysis over different transmission policies is performed and the corresponding results are plotted. The effect of diversity on the performance measures are demonstrated. In contrary to Shannon’s ergodic capacity, the delay-constrained effective rate is used to define the maximum data rate of the real-time applications in 5G and beyond networks. We have studied the effective throughput performance of the multi-antenna system over the BX fading channel and FSF fading channel. The closed-form mathematical expressions for the effective capacity (EC) are derived in terms of Meijer-G function and the effect of different fading parameters on the effective throughput of the system is vii demonstrated. The simplified asymptotic expression for high signal-to-noise ratio (SNR) and low SNR regimes is provided to gain more insight in to the system. The intelligent reflecting surfaces (IRS) is a newer technology that is being used in 5G and beyond networks to improve the system performance. Due to this, the IRS-aided systems have been actively investigated. The application of the derived formulation for the IRS-aided system over the BX and SFS channels are studied. Interesting results of the system performance in terms of channel parameters are demonstrated. For the expressions having infinite series representation, the truncation error has been provided wherever possible. The effect of fading parameters on the performance measures are demonstrated through analytical results. Simulation results are corroborated along with the numerical results to verify the correctness of the proposed formulations. The results presented in this study can be used in designing the communication systems for real-time applications in next-generation wireless networks.