Joint Mode Selection and Power Control for Underlaying Device-to-Device Communications in LTE-A Cellular Networks

Abstract

Device to device (D2D) communications are viewed as a vital technology nowadays which allow direct transmission between two cellular devices without through base stations In this thesis D2D communications nested in a cellular network transmitting data to each other directly using the uplink frequency resource of cellular users In particularly we considered two kinds of modes direct D2D mode and relay assisted D2D mode respectively Relay assisted transmission could efficiently enhance the performance of D2D communications when D2D users are too far away from each other or the quality of D2D channel is not good enough Aiming at maximizing the overall system throughput while guaranteeing the signal-to-noise-and-interference ratio (SINR) of both D2D pair and cellular links we utilize a mode selection strategy between direct D2D mode and relay assisted mode to ensure the maximal system throughput However co-channel interference between the D2D links and the cellular links is a severe problem; thus we proposed a power control algorithm to mitigate the interference Furthermore how to properly assign the reusing channel and control the transmit power to mitigate the co-channel interference between the D2D links and the cellular links is a main challenge To simply our problems we identified candidate cellular users whose frequency resource can be reused by D2D pair and then decomposed our problem into two subproblems two modes respectively Finally we proposed a power control scheme using the characteristic of convex function to optimize our problems The results show that by proper mode selection and power control D2D communications can effectively improve the total throughput without generating harmful interference to cellular networks

Date of Award	2016 Aug 22
Original language	English
Supervisor	Hsiao-Hwa Chen (Supervisor)