Full Duplex (FD) technology is considered as one of the next big leap in the evolution of modern WLANs. Allowing a node to simultaneously transmit a data frame while in receive mode, can theoretically double the system throughput. However, several requirements must be fulfilled in order for FD operation to manifest. One obvious prerequisite is that the Medium Access Control (MAC) mechanism must allow two nodes to access the shared medium simultaneously. In modern WLANs the standard MAC layer mechanism is the Distributed Coordination Function (DCF), which is specifically designed to avoid such situations. FD communications may also take place when the physical placement of the communicating parts involves the existence of hidden terminals which, in standard Half Duplex (HD) communications, imposes a significant problem. This paper investigates the performance of the Carrier Sense Multiple Access with Collision Avoidance (CSMA/CA) protocol, which constitutes the basis of the DCF mechanism, in FD WLANs with hidden terminals, and compares it with the standard HD case. Our analysis is based on performance modelling. Results indicate that, under the DCF regime, FD technology exhibits an exiguous performance improvement, in terms of saturation throughput, when compared with its half duplex counterpart.

翻译：全双工(FD)技术被视为现代WLAN演进中的下一个重大突破。允许节点在接收模式的同时传输数据帧，理论上可使系统吞吐量翻倍。然而，FD操作需要满足若干前提条件。一个显而易见的必要条件在于：媒体接入控制(MAC)机制必须允许两个节点同时访问共享介质。现代WLAN中的标准MAC层机制是分布式协调功能(DCF)，其专门设计用于避免此类情况。当通信双方的物理位置涉及隐藏终端时，全双工通信也可能发生——而在标准半双工(HD)通信中，隐藏终端会引发严重问题。本文研究了基于DCF机制基础的载波侦听多路访问/冲突避免(CSMA/CA)协议在包含隐藏终端的全双工WLAN中的性能，并将其与标准半双工场景进行对比。我们的分析基于性能建模。结果表明，在DCF机制下，全双工技术相较于半双工技术，在饱和吞吐量方面的性能提升微乎其微。