Performance Analysis Of Virtual Full-Duplex Wireless Networks

Self-interference cancellation based in-band full-duplex(IC-FD)wireless systems have become a hot research topic recently.Enabling simultaneous transmission and reception in the same frequency band,IC-FD is considered as a potential way to cope with the scarce spectrum resources.However,self-interference cancellation techniques are only be implemented in laboratories and too complex to be used in practical appli-cations.The main reason is the interference caused by the transmitting terminal itself is usually several orders of magnitude stronger than the desired received signals.There-fore,it is necessary to explore an alternative scheme to achieve full duplex in-band.Beyond low cost and high reliability,this alternative scheme is excepted to be easier to deploy than self-interference cancellation.Extending the full-duplex concepts from physical layer to access layer,rapid on-off-division duplex(RODD),which enable si-multaneous transmissions and receptions over a period of frame,is an self-interference avoidance based approach that enables frame-level in-band full-duplex and can improve the throughput.RODD transmits signals according to a randomly generated on-off mask over the period of frame,and receives the desired signals through the off slots.Therefore,users can receive and transmit signals simultaneously over a frame,thus realizing frame-level in-band full-duplex.However,the physical layer of is still restricted by the half-duplex constraints,so it is called virtual in-band full-duplex.Based on the description above,we analyzed the performance of RODD and its related technologies from several aspects.The specific contents are as follows:·We introduce the concepts of RODD and establish a mathematical model to in-vestigate the throughput of RODD in ad hoc networks.By treat the link abstrac-tion as a multi-access channel with erasure,theoretical achievable rates are de-rived.Finally,the theoretical results are verified by numerical simulations,and the throughput performance of RODD is shown to be superior to other random access schemes.·We analyze the average delay of ad hoc networks under RODD.The stability con-ditions of the networks are analyzed through the dominant system and Lyapunov drift theorem.The simulation results show that the delay performance of RODD is better than that of random access schemes,but worse than that of TDMA,which can adaptively allocate time resources.·We investigate the influence of duty cycle on the energy efficiency of the network under a new energy consumption model.Considering the total power consump-tion when transmitting is different from that when sleeping,we establish a new power consumption model.Since the introduction of"off" slots makes duty cycle more important,we will analyze the optimal allocation of resources to maximize the energy efficiency under the total power constraints.The results show that the choice of duty cycle is particularly important to point-to-point links,while in multi-user uplinks,TDMA is better than NOMA.Our results show that RODD,compared with random access schemes,has advan-tages in many aspects,such as throughput and delay.But in order to improve spectrum efficiency and energy efficiency,interference and erasure caused by simultaneous trans-mission of multiple users should be avoided as far as possible.For this reason,we also give the design framework based on minimizing the correlation of on-off masks.