Online Relay Switching in the presence of Dynamic Obstacles in millimeter wave D2D communication

Abstract

With the ever-increasing number of diverse user-equipments (UEs) and their require- ment of high data rate several modi cations have been done on previous wireless technologies leading to the evolution of 5G device to device (D2D) communication. The use of millimeter wave (mmWave) channels is gaining popularity for short-range D2D communication due to its high available bandwidth. But due to the excessive penetration loss su ered by mmWave, it is necessary to facilitate D2D communica- tion along the line of sight (LOS) path. In the D2D communication, UEs also acts as relays to forward the data packet transmitted by the source to receiver. In the presence of dynamic Obstacles as well as due to the motion of UEs, blockage of LOS is highly probable which makes relay selection quite challenging. We are proposing the unique strategies based on the geometric approach to nd the priority of the relays for a given D2D pair. In case of blockage of LOS by dynamic or static obstacles, the respective D2D pair might switch to the other high priority relay. We are modeling the entire problem as a game-theoretic auction framework with the goal of increasing the overall throughput of the system as well as prevention of starvation of any D2D pair. We perform centralized relay selection using the global information but found that this might not be su cient to reduce packet loss adequately. Motivated by this, we develop an online relay switching (ORS) algorithm, where we perform pre-emptive distributed switching using the local information of the UEs to reduce any further packet loss due to the blockages. Through simulation we show that in the presence of large number of dynamic obstacles, ORS not only gives a signi cant improvement in the average throughput and packet loss but also the lower starvation of D2D pairs than the traditional approaches which does not take into account the pre-emptive switching of the relays in case of blockage. 1