Intelligent Reflecting Surface assisted millimeter wave communication for achievable rate and coverage enhancement

Abstract

In a wireless terrain, the presence of various obstacles leads to compliance of non-Line-of-sight (NLOS) norms between transmitter and receiver, which renders severe degradation in the service quality of the communication link and thereby limits the anticipated performance. The expected achievable rate is primarily affected by the location of the mobile receiver as well as the characteristics of the obstacles surrounding it for any wireless terrain. The achievable rate can be improved by deploying Intelligent Reflecting Surface (IRS) panels at properly identified locations. The presence of IRS panels stimulates a supplementary wireless channel that enhances reliable end-to-end connectivity between transmitter and receiver, especially when the direct path (Line-of-sight, LOS) is either experiences severe signal degradation or completely missing in shorter epochs. Using IRS, the performance of the wireless network can be improved by smartly re-configuring the passive reflecting elements which are embedded on a planar surface. In this paper, due to inherent geographical terrain specific attributes and the mobility aspects of a receiver, the end-to-end characterization of the wireless channel between a pair of transmitter and receiver is modeled using cascade arrangements of Time-Invariant (TI) and Time-Variant (TV) channel's impulse response. Further, the overall performance of wireless links is evaluated in terms of the key performance measures, namely, achievable rate and the span of network coverage. Obtained simulation results for two distinct geographical terrains validate the enhanced status of performance measures in IRS-assisted wireless terrains while regulating the system parameters, namely, IRS panel specifications, transmit power, and the velocity of the mobile receiver.