MAC Protocols And Performance Analysis For In-Band Full-Duplex Wireless Networks

In-Band Full Duplex(IBFD)wireless communication,which allows nodes to transmit and receive simultaneously in the same frequency band,can theoretically double its spectral efficiency and network throughput relative to networks with HD operation.With this advantage,it has been one of the important research directions of5 G system to fully tap the wireless spectrum resources and new air interface technology.The advanced self-interference cancellation technologies have achieved the ability to suppress self-interference below the noise floor that does not interfere with desired signal reception,supporting a single node to transmit and receive in IBFD mode.However,to further apply IBFD to dual packet transmission among multiple nodes in wireless networks,we also need to research medium access control(MAC)protocols.In this paper,according to the requirement of IBFD wireless communication among multiple nodes,the IBFD MAC protocols are studied and the performance analysis is carried out.Based on the current research status of IBFD wireless communication,the key technologies of IBFD MAC protocol are summarized.Firstly,to better support MAC protocols design,self-interference cancellation and Inter-Node Interference(INI)suppression technologies of physical layer are introduced.Then the protocols and scheduling mechanisms of IBFD MAC layer are studied.Based on this,the influence of Residual Self-Interference(RSI)and INI on the research and design of IBFD MAC protocol is analyzed.At last,802.11 RTS/CTS(Request to Send/Clear to Send)mechanism is studied,and the limitations of RTS/CTS application in IBFD wireless network are summarized,which lays the foundation for the research of IBFD MAC protocols in this paper.An IBFD medium access control mechanism for centralized wireless networks is proposed.The current Half-duplex(HD)medium access mechanism RTS/CTS has been applied to IBFD wireless networks.However,it can only assist to establish symmetric dual link but cannot reserve channel for the downlink of asymmetric dual transmission,which limits the improvement of network throughput.In this paper,by using three-way handshaking scheme,a novel IBFD MAC mechanism RTS/SRTS(Second Request to Send)/CTS for use in centralized wireless networks is proposed.In this approach,IBFD wireless communication only requires one channel access for symmetric or asymmetric dual link establishment.After constructing network model,the control frame structure of SRTS is designed based on communicationrequirements.Then the medium access and packet transmission procedure of the proposed mechanism are detailed.Finally,a discrete-time Markov model is used to analyze the network performance.Simulation results show that the throughput of IBFD wireless network nearly doubles that of HD wireless network.To suppress the INI in IBFD asymmetric dual communication,an IBFD MAC mechanism considering capture effect is proposed.In asymmetric dual link,if uplink transmitter and downlink receiver are exposed to each other,the downlink receiver would be affect by the uplink transmitter's INI in the same frequncy when dual packet transmission.To solve this problem,the IBFD MAC mechanism RTS/SRTS/CTS with capture effect(RTS/SRTS/CTS-CE)is proposed by using capture effect to suppress INI.Based on the condition of a node to capture signal,the received power ratio is added into the frame structure of SRTS and CTS respectively.Then specific medium access and packet transmission procedure of the proposed mechanism are detailed.By medium access,the received power ratio is deliveried to assist communication nodes to adjust transmit power for packet transmission.Moreover,a Markov model considering capture effect is established for performance analysis.Simulation results demonstrate that the RTS/SRTS/CTS with capture effect further improves network performance.The performance of centralized wireless networks with an IBFD AP(Access Point)and HD users is analyzed based on M/G/1 queueing model.In this hybrid wireless network environment,IBFD AP can communicate with two HD users in asymmetric dual link,and RTS/SRTS/CTS mechanism can support this communication.According to the problem of INI existing in asymmetric dual link,an INI suppression method for both centralized and distributed wireless network is proposed.Based on this,SRTS and CTS frame structure are adjusted to help suppressing INI by medium access.After detailing the asymmetric dual transmission,the delay performance of IBFD AP is analyzed based on M/G/1 queuing model,and the service time and the amount of service of IBFD AP to be carried out are studied as compared to that of HD AP.Simulation results show that IBFD AP's delay performance is far superior to HD AP,and IBFD AP can carry more data transmission services in the network with more users.An IBFD medium access control mechanism for distributed wireless networks is proposed.In this network environment,if a destination node has no packet to transmit,it would only transmit in HD mode with its source node,which works equivalently toHD wireless communication.To solve this problem,a medium access control mechanism for use in distributed IBFD wireless networks,named as FD-DMAC(Full-Duplex Distributed MAC)is proposed.Firstly,the network model is built and the transmission modes in this model are classified as HD mode,symmetric IBFD mode,source-based asymmetric IBFD mode and destination-based asymmetric IBFD mode.Secondly,the control frame structures are designed on demand,where transmission mode field is added.In this approach,a node in the network can obtain the transmission mode of communication nodes and decide whether itself is suitable to contend the uplink transmission opportunity during medium access,which can improve the dual transmission probability.Then the medium access and packet transmission procedure of FD-DMAC are detailed.At last,Markov models under saturated and unsaturated condition are developed respectively for performance analysis.Simulation results demonstrate that the throughput of IBFD wireless network nearly doubles that of HD wireless network.Additionally,the non-saturation degree of the network has little influence on FD-DMAC mechanism,which can provide more stable performance for distributed wireless networks.The research on IBFD MAC protocol in this paper can assist to improve the throughput and reduce the transmission delay of IBFDwireless network.It provides theoretical and protocol supports for IBFD wireless communication with large user and massive data volume.