Capacity Optimization Resource Allocation Scheme For D2D Communication Underlaying Cellular Networks

Mobile communication technology has brought convenient service to people’s life in the21stcentury, accompanied by the increase in the number of mobile users. However, the radio spectrumsources are non-renewable and limited. In order to solve this problem, research on radio resourcemanagement and improvement on utilization of radio spectrum resource has received muchattention. In recent years, Device-to-Device technology has become an emerging research topic inthe field of mobile communications. A lot of research results show, the D2D communications cannot only save the transmit power of the mobile terminal, but also has significant advantage inimproving the utilization of spectrum resources.This thesis first introduces the development of cellular mobile communication systems andD2D communication as an underlay in LTE system. Then, OFDM technology, system framestructure and resource scheduling processes are introduced. Next, this thesis has studied radioresource management when D2D users share radio resources with cellular users. Fornon-orthogonal mode, this thesis studies the interference caused by radio resource sharing andsimulates the interference plot that D2D user caused to cellular user.A joint resource allocation and resource reuse scheme is investigated to control theinterference caused by D2D communication, in which resource allocation to cellular users isemployed on proportional fair algorithm and resource reuse to D2D users is employed on agreedy heuristic algorithm. Simulations show that sum throughput is improved using the proposedscheme in two setting scenarios, which is cellular users decrease and fixed with D2D usersincrease.This thesis also studies the link adaptation technology after D2D communication introduced.A cross-layer optimization design based on link adaptation is proposed in D2D system. The jointadaptive modulation coding technique and auto repeat request technology design can improve thespectrum efficiency of the system, which would make up for the interference caused by D2Dcommunication. Simulations prove D2D communication cross-layer design has a higher systemcapacity than fixed modulation coding mode, which increased by about5%in a simple scenariowith4couple of D2D users and4cellular users.