Intelligent Reflecting Surfaces Assisted UAV Communications for IoT Networks Performance Analysis

Abstract : The increasing demand for wireless connectivity and the emergence of the notion of the Internet of Everything require new communication paradigms that will ultimately enable a plethora of new applications and new disruptive technologies. In this context, the present contribution investigates the use of the recently introduced intelligent reflecting surface (IRS) concept in unmanned aerial vehicles (UAV) enabled communications aiming to extend the network coverage and improve the communication reliability as well as spectral efficiency of Internet of Things (IoT) networks. In particular, we first derive tractable analytic expressions for the achievable symbol error rate (SER), ergodic capacity, and outage probability of the considered set up. Following this, we also derive tight upper and lower bounds on the average signal-to-noise ratio (SNR). Our derivations are then compared with the corresponding asymptotic performance, based on the central limit theorem (CLT) assumption, which reveals that the asymptotic SNR falls within the area between derived bounds, and approaches either bound depending on the number of reflective elements (REs). We further show that the asymptotic SER becomes in a tight agreement with the corresponding exact simulation SER for N=16. In addition, the offered results demonstrate that the use of the IRS is significantly effective as they assist in improving the achievable SER by five orders of magnitude. We further demonstrate that, in terms of achievable ergodic capacity, IRS-assisted UAV communication systems can exhibit ten times higher capacity compared to conventional UAV communications. Based on the above, these results and related insights are anticipated to be useful in the design and deployment of IRS-assisted UAV systems in the context of beyond 5G communications, such as 6G communications.

 EXISTING SYSTEM :

 ? We provide an extensive review on the stochastic analysis of performance limit and asymptotic behavior of IRSassisted wireless networks, which are not covered by the existing review papers. ? Most of the existing analytical works are built based on the above path loss and signal models, which are basis for the following performance analysis and optimal design of IRS-assisted wireless systems. ? To maximize the data rate, a modulation scheme is designed for the IRS that is interference free for existing devices. ? While a large majority of the existing works assume perfect channel information and focus on static maximization problems. ? Existing approaches for the IRS’s channel estimation generally assume that only one scattering element is active each time, while all the other elements are inactive.

 DISADVANTAGE :

 ? A joint beamforming problem is formulated to maximize the received signal power at the user, by jointly optimizing the AP’s transmit beamforming and the continuous phase shift of each scattering element. ? The SNR or capacity maximization problems can be naturally extended to the MU scenarios. ? The optimal user assignment scheme can be effectively found by solving classical linear assignment problems defined on a bipartite graph. ? This problem is approximately solved by the alternating optimization and path-following algorithms in an iterative manner.

 PROPOSED SYSTEM :

 • The idea of programmable wireless channels or environment is proposed in by using hypersurfaces, i.e., software-controlled metamaterials, to cover physical objects in the radio environment. • Extensive simulation results validate that the proposed channel model matches well with the experimental measurement results conducted in a microwave anechoic chamber. • A stochastic geometry method is proposed to analyze the downlink coverage probability under the assumption that the locations of base stations follow a homogeneous Poisson point process, the blockages and reflectors are deployed in straight line segments with uniformly distributed orientation and length. • In the sequel, we review the main optimization formulations and solutions proposed for IRS-assisted wireless systems.

 ADVANTAGE :

 ? It is worth mentioning that a comprehensive performance analysis of IRS based UAV communications has not yet been investigated. ? Motivated by the above, we provide a comprehensive investigation of the performance of mounted IRS-assisted UAV communications assuming path loss and channel models that are unique to UAV communications. ? To investigate the system performance, the derived bounds are compared with the asymptotic results based on the central limit theorem (CLT). ? We further investigate the system performance and path loss as a function of UAV location, and analyze the effect of the number of REs on the system performance. ? It is evident that as the UAV moves towards either side of the communication link, the performance improves.