Interference Reducing Based Resource Allocation For Device-To-Device Communication Underlaying Lte-Advanced System

As the licenses of TD-LTE and LTE-FDD is allocated by ministry of industry and information technology. Users are able to be benefit from the LTE networks which has applied in our life. Compared with traditional LTE system, lager up/down link peak rate and system capacity is realized by LTE-A system which is based on traditional LTE system. Communication quality in some special environment such as hot region or indoor environment still cannot be guaranteed by tradition LTE. So, based on LTE-A system, device to device technology (D2D) aiming to reduce base station traffic load, increase the cell coverage, raise communication quality of edge user as well as throughput of system is added in LTE by researchers. In this thesis, LTE-A system and D2D communication have been together. In downlink time slot, largest system throughout can be realized through the reasonable resource allocation for D2D users.The thesis is organized as follows. First of all, research background, significance and research status are introduced in this thesis. Secondly, the system architecture and the key technology of LTE-A are presented, and a more detailed introduction about D2D technology as well as interference which is brought by D2D communication users multiplexing cellular communication system is gave. Then, resource allocation problem of D2D communication multiplexing downlink resource is mainly introduced. From the angle of reducing interference of D2D communication, the Minimal interference resource allocation algorithm is proposed, and from the angle of guaranteeing the throughput of edge cellular, the reusable resource allocation algorithm. As the result shows, compared with algorithm in paper [10], larger throughput in communication system is realized by two proposed D2D improved algorithms in the thesis. When the number of D2D users in cellular is different, two improved algorithms have their own advantage. Finally, In order to improve the communication quality of edge cell, Fractional Frequency Reuse (FFR) and D2D communication are combined together, an algorithm about D2D communication resource allocation based on distance in FFR cell is proposed. Through the cell partition of cellular, the reused D2D users who are further from the cellular are chose to reduce interference. As the result shows, using the improved algorithm based on distance, not only the throughput is improved compared with paper [20], but also the ratio of the area of edge cell and the best center contributing maximum system throughput are found.