Energy-aware Mode Selection Mechanism For Cross-cell D2D Communications

As one of the key technologies of 5G communication,D2D(Device-to-Device)communication plays an important role in improving spectrum utilization and system capacity.However,D2D communication is faced with the problems of excessive co-channel interference and energy consumption of terminal devices.Therefore,this dissertation studies the mode selection strategy in cross-cell D2D communications scenario in order to solve co-channel interference problem and energy consumption problem.Although the research on energy-efficient D2D mode selection has made some progress,most related work do not considered the characteristics of D2D communication and signal channel.The details are listed as follows: 1)Part of research assumed that the channel fading of D2D communication is Rayleigh fading,which does not reflect the characteristics of D2D users who can communicate at short distances.2)Most studies assumed that the channel state information is completely known,but do not consider that the information will be affected by the environment as it transmittes through the channel,which makes it difficult for the base station to obtain the imperfect channel state information.To accurately evaluate the system performance,channel uncertainty needs to be considered.3)The position of the terminal device is random during the energy harvesting of the mobile device,so the link distance cannot be directly assumed as a constant.To this end,this dissertation studies cross-cell D2D mode selection mechanism based on energy-aware.The main work is as follows:1.A communication model and a channel model for cross-cell D2D communication are established.Compared with the existing research,the model takes into account the situation of the long communication distance between mobile users and the channel status during D2D user communication.In this dissertation,a cross-cell D2D communication model is established according to the limitation of the coverage of the base station,that is,the receiving end and transmitting end of the communication link are not in the same cell.This study mainly analyzes the channel model based on the communication distance.For example,the channel fading of the D2D link in reuse and dedicated modes is Rician Fading;the channel fading of the D2D link in cellular mode is Rayleigh fading;and the channel fading of the cellular link and interference link in the three modes is Rayleigh fading.2.For D2D mode selection problem,this dissertation analyzes the probability that the signal-to-interference ratio of the link receiver is greater than the predetermined threshold when the channel state information is not fully known,that is,the success probability of the communication link,and derives the ergodic capacity(EC)of the link by using stochastic geometry and Shannon's theorem,and then designs mode selection algorithm based on the system capacity and its ratio to the total energy consumption.3.Based on the D2D mode selection of energy harvested,this dissertation analyzes the power(including signal power and interference power)received by the D2D receiver and the cellular receiver,and derives the closed-form expression of the ergodic energy-harvested(EEH)at the receiver under the power splitting of Simultaneous Wireless Information and Power Transfer(SWIPT).With the analyses of EEH and EC,an energy-efficient D2D mode selection mechanism based on SWIPT is proposed.In summary,this dissertation studies the mode selection problem in cross-cell D2D communication scenario,establishes a communication model and a channel model,and designs a mode selection mechanism,which effectively improves the system energy efficiency and energy utilization.Finally,through extensive numerical simulation experiments,the link success probability,EC,and system energy efficiency are analyzed under the conditions of perfect channel state information and imperfect channel state information,and the correctness of the theoretical conclusions is verified.