D2d Key Technology Research In The Future Mobile Communication System

Mobile data, video, and TV services these applications are now becoming anessential part of consumers’ lives. The number of mobile subscribers is growing rapidlyand bandwidth demand due to data and video services is increasing. There is a need forcapacity to increase in order for mobile broadband, data access, and video services toengage the end consumer. Device-to-device (D2D) communications underlayingcellular networks entails the ability of a cellular network to allow devices tocommunicate directly with each other in the operating (licensed) spectrum of thecellular network. With the application of specific rules and strategies, D2Dcommunications offloads the mobile network and increases the spectral efficiency, andit is also able to introduce and promote the development of new services.The main purpose of this paper is to introduce the application of the D2Dcommunication technology in future mobile communication systems and its keytechnologies. In this thesis it is developed a method for the application of D2Dcommunication, controlled by a cellular network. And it details the basic concepts,system module, application scenarios, the advantages and disadvantages of the D2Dcommunication technology and so on. By deriving the theoretical upper bound on theinterference, equations have been analytically derived which describing the minimumdistances to be maintained between simultaneously operating links, to achieve a givenminimum SINR. A strategy has been devised to group and schedule links which fulfillthese minimum requirements, so that multiple links in the same group may operatesimultaneously. Different simulation scenarios have been set and greedy groupingalgorithm has been used to compare the simulation results to find the most suitable forgroup the D2D link and the scenario, thus the results can provide theoretical support forthe enhancement of system capacity. A scenario representing a realistic urbanenvironment has been shown on this thesis to provide a reference for further study ofD2D communication technology.A power control method in a single cell has been described in this thesis to furtherimprove the utility efficiency of frequency resource. The transmit power reduction method of D2D communication has been used to avoid too much interference to cellularcommunications. The simulation results show that it can thus expect scheduling gain byproperly scheduling the DL/UL resources to the D2D communication according to theposition of the D2D pair.This study has important implications on the D2D communication in wirelesscommunication system.