# Design and Performance Analysis of an In-Band Full-Duplex MAC Protocol for Ad Hoc Networks
## 2 Literature Review  
With the advancements in the physical layer, an effective MAC protocol is crucial in IBFD communications to exploit its benefit properly. A substantial amount of MAC protocols is proposed for ad hoc networks and other types of wireless networks. Although many of these protocols are designed using IBFD technique, all of them do not consider all possible types of IBFD communications as well as most of them are not proposed for ad hoc networks. Moreover, some of these do not consider the Inter-user-interference (IUI) and some cannot support the hidden and exposed terminal problems. A MAC protocol is designed in [2] for both infrastructure-based WLAN and ad hoc network, which supports all possible TNFD and BFD communications. However, this MAC cannot support the condition when transmitter and receiver nodes are out of the transmission range between each other in ad hoc networks. Moreover, the SR always measures the signal to interference ratio in that MAC during TNFD communications to extinguish IUI. Thus, it increases the computational load and network complexity. Furthermore, this design does not demonstrate the Network Allocation Vector (NAV) for various nodes. The authors in [9] proposed an OFDM-based 20 MHz multi-antenna FD MAC protocol. Another FD MAC has also been proposed in [10]. Both MAC protocols in [9,10] only consider BFD  
Figure 2: Proposed network model for AdHoc-FDMAC. The single alphabets in the figure are node labels. communications, but TNFD communications are not supported. Moreover, those MAC protocols are not for ad hoc networks. Another MAC protocol is proposed in [11] for the ad hoc networks using IBFD communications, where all the nodes are FDNs. This MAC is designed for BFD and destination-based TNFD communications, but it has not considered the source-based TNFD communications. Moreover, IUI is not considered in this MAC. Therefore, IUI will affect the TNFD communications greatly. In [12], a FD MAC protocol is proposed for ad hoc networks, which considers only BFD communications and destination-based TNFD communications, but source-based TNFD is not considered. Furthermore, in this MAC, to reduce IUI between PT to SR, ST uses its past information. This technique is not efficient for the networks where topological changes occur very rapidly. A MAC protocol is proposed, named the distributed-access FD MAC in [13] for ad hoc networks, where the transmitting node transmits data to the receiver via intermediate nodes and all the nodes are FD capable. However, this paper does not describe how the path is selected from the transmitter to receiver. Recently, an IBFD MAC is proposed to perform Collision-Free FD (CEFD) communications among neighbours [14]. Here, the modified Request to Send (RTS) and Clear to Send (CTS) frames are used to reduce control message overhead, and these are used to reserve the data slot for FD transmission. However, the Acknowledgement (ACK) frame is not used here. Therefore, the source node is not informed whether data transmission is successful or not. It shows that no collision occurs in the data slot during data transmission. However, it is not clear how the data from a distant node will reach to the monitoring station or control center in an ad hoc network. In [15], an FD-MAC protocol is proposed for the infrastructure-based WLAN, where a shared random backoff, virtual backoff and header snooping methods are used for different types of IBFD of data transmission. This MAC supports BFD and source-based TNFD communications, but it does not consider destination-based TNFD communications. Furthermore, no handshake mechanism is used by this MAC; therefore, this MAC is not able to mitigate the hidden terminal problem. For asynchronous FD communications in ad hoc networks, a MAC is designed using the IBFD technique in [16]. That MAC only supports BFD communications; the TNFD is not supported by this MAC. In [17], an asymmetric MAC protocol is proposed for the infrastructure-based WLAN.