D2D Neighborhood Discovery by a Mobile Device

In order to enhance the capacity of the Fifth Generation and beyond (5GB) cellular networks, third generation partnership project (3GPP) has provided guidelines for enabling device-to-device (D2D) communication. An essential requirement for successful D2D communication is the users' ability to discover each other, specially in the out-of-network scenarios. While there has been some research effort in the area of D2D discovery, most of the works assume that the devices are static. In a typical mobile environment, the constraints like time-to-discovery, etc, are more rigid and deserve investigation. This paper formulates a mathematical model for a mobile device's neighborhood discovery as it moves across an area that has other D2D users. In particular, we determine the expected number of users discovered by a mobile device while moving in a straight line between two way-points following random waypoint mobility. The model is verified using Monte-Carlo simulation and can be used for future analysis of mobile D2D-discovery.