Research On Full-duplex Technique In Wireless Communication

With the rapid development of the wireless communication network,the spectral efficiency is increasingly crowded.Meanwhile,in the face of thou-sand fold increase of data traffic and diverse business traffic,the research and development of 5th generation(5G)are evolving.As one of the key potential technology in 5G,full-duplex communication has been widespread concerned due to its high spectral efficiency and its ability to double the system capac-ity.Full-duplex communication means that wireless nodes can transmit and receive signals using the same frequency at the same time,which can improve spectrum efficiency.Compared with the half-duplex communication,which transmits or receives signal using different time or spectrum,full-duplex com-munication has been regarded as one of the efficient way to solve the spectrum shortage problem.However,full-duplex communication experiences serious self-interference,thus the system performance decreases quickly in this situa-tion.Recently,some works put attention on self-interference cancellation,and the self-interference can be reduced to the noise level.Thus,full-duplex com-munication can be put into practice.As the communication node is energy constraint in energy constraint network,the lifetime of the system is limited.Simultaneous wireless information and power transfer(SWIPT)method can replenish energy from the radio frequency(RP)signals,and it is an attractive energy harvesting(EH)technique for self-sustaining wireless networks.The innovations and contributions can be summarized as follows:1)In this thesis,a transmission mode selection scheme is proposed for Device-to-Device(D2D)communications.We investigate the outage perfor-mance for D2D communications underlaying cellular networks,where potential D2D users reuse the spectrum of uplink cellular users.In the considered sce-nario,we analyze and understand how the underlay D2D communication affects the cellular network performance.Most of the previous researchers only con-sider the performance for the full-duplex or half-duplex D2D network.How-ever,the wireless environment is complex in reality,thus the full-duplex com-munications is not always better than the half-duplex communications.Hence,we investigate the outage performance for hybrid full-duplex/half-duplex D2D communications.In particular,we present a tractable analytical framework for a full-duplex or half-duplex D2D-enabled cellular network,and the outage per-formances of the full-duplex or half-duplex D2D receiver and the typical cellu-lar user are presented.Meanwhile,the spectral efficiency of the hybrid-duplex D2D-enabled cellular network is given.Finally,numerical results are presented to verify the proposed scheme.From the simulation results,we can see that the proposed scheme can improve the system outage performance.Moreover,the system spectrum efficiency of the proposed hybrid full-duplex/half-duplex D2D scheme can be improved compared with the traditional full-duplex D2D scheme and half-duplex D2D scheme.2)In this thesis,we try to enhance the D2D security performance by in-troducing full-duplex cellular users,and the full-duplex cellular users intend to jam eavesdroppers by transmitting artificial noise while simultaneously receiv-ing useful signal from its serving base station.In the considered scenario,we in-vestigate the security issues for D2D communications underlaying cellular net-works with eavesdroppers overhearing D2D communications.Using stochastic geometry,the D2D connection probability,the D2D secrecy probability and the full-duplex cellular user connection probability are analyzed.Moreover,an ef-fective algorithm is proposed to improve the D2D secrecy probability subject to the security constraints.Our analytical results match well with the simulations.From the simulation results,it is clear that the D2D ergodic secrecy rate of the proposed scheme outperforms that of the traditional D2D underlaying cellular networks without full-duplex cellular users.3)In this thesis,a joint relay-user selection(JRUS)scheme is proposed for full-duplex relay network,and we investigate the outage performance for the considered network.In our scenario,there exist one source node,multi-relay node and multi-user node,and the direct link between the source node and the user node is considered to convey information.Each relay node is equipped with two antennas and works on full-duplex transmission mode,where one an-tenna for receiving and another for transmitting.Each full-duplex relay node is energy-constrained,thus energy harvesting is considered.Based on the consid-ered relay network,a JRUS scheme is proposed,and the outage performance of the proposed selection scheme is provided.Meanwhile,the diversity order and the impact of the direct link on the system outage performance are investi-gated.Furthermore,the optimal power-splitter factor is obtained by minimizing the derived outage probability.Finally,numerical results demonstrate the ac-curacy of our performance analysis and the efficiency of the proposed JRUSscheme.