Assisted Handover Based on Device-to-Device Communications in 3GPP LTE Systems

The ever increasing demand in mobile data traffic, fueled by the fast proliferation of bandwidth-hungry wireless applications and services, has imposed new challenges on data rate requirements in emerging 5G systems. To meet these demanding expectations, the mainstream direction for the network operators is to deploy a higher density of various cellular infrastructure. Along these lines, this paper seeks to augment future handover operation by employing the recent Device-to-Device (D2D) communications technology. The underlying rationale behind our proposal is to equip the mobile users with better-quality direct links and thus improve the resulting service perception under the typical 3GPP LTE handover procedures. The proposed D2D-assisted handover scheme is able to efficiently offer the attractive energy efficiency, data rate, and packet delivery ratio benefits. By utilizing the tools from stochastic geometry, we derive the main performance metrics of interest for our solution, such as the distribution of signal-to-noise ratio experienced by a user entering the zone of overlapping coverage and the amount of time it remains in contact with a chosen D2D partner. The gains on top of the standard LTE handover procedures for all the considered parameters are further confirmed by extensive system-level simulations in video streaming and multimedia content downloading scenarios.