Intelligent-Reflecting-Surface-Assisted GFDM Communication Systems

Abstract

Demands for higher data rates is an inevitable fact. Therefore, the effect of the frequency selectivity and time variation of communication channels will be more significant. One effective technique to combat the doubly dispersive channels is generalized frequency division multiplexing (GFDM) scheme. Nevertheless, nonorthogonality of the used prototype filter can deteriorate the GFDM performance. On the other hand, intelligent reflecting surface (IRS) is a new revolutionary technology for future wireless networks. IRS can smartly reconfigure the propagation environment in order to improve the efficiency of the communication systems. In this article, IRS is applied in a GFDM communication system to enhance the system's performance. In this way, an IRS-assisted GFDM communication system model is proposed. The goal is to design the reflecting coefficients of the IRS such that the total noise power at a GFDM block is minimized. In order to obtain an effective solution, the optimization problem is converted to a quadratically constrained quadratic program (QCQP). The developed QCQP problem is convex, which can be solved by using an iterative algorithm. An analytical derivation of the maximum achievable rate (MAR) and bit error rate (BER) of the proposed IRS-assisted GFDM system is provided. Also, in simulations, the performance of the proposed method is compared with the conventional GFDM system in terms of MAR and BER. Simulation results confirm that using IRS by employing the proposed method dramatically improves the performance of a GFDM system.