Full duplex communication promises a paradigm shift in wireless networks by allowing simultaneous packet transmission and reception within the same channel. While recent prototypes indicate the feasibility of this concept, there is a lack of rigorous theoretical development on how full duplex impacts medium access control (MAC) protocols in practical wireless networks. In this paper, we formulate the first analytical model of a CSMA CA based full duplex MAC protocol for a wireless LAN network composed of an access point serving mobile clients. There are two major contributions of our work: First, our Markov chain-based approach results in closed form expressions of throughput for both the access point and the clients for this new class of networks. Second, our study provides quantitative insights on how much of the classical hidden terminal problem can be mitigated through full duplex. We specifically demonstrate that the improvement in the network throughput is up to 35-40 percent over the half duplex case. Our analytical models are verified through packet level simulations in ns-2. Our results also reveal the benefit of full duplex under varying network configuration parameters, such as number of hidden terminals, client density, and contention window size.
There has been some recent effort in characterizing FD's performance from a theoretical standpoint. In @cite_11 , achievable throughput in full-duplex is characterized as opposed to other channel access schemes such as MIMO and MU-MIMO. In @cite_24 , theoretical bounds for full-duplex gain over half-duplex has been derived for various topologies as a function of difference between transmission and interference range. It has been shown that when these two ranges are equal for a randomly deployed ad hoc network the asymptotic bound for full-duplex gain is only $28 , none of these works consider a methematical modeling of a real-world FD protocol. Our work serves in bridging this gap, and we use the CSMA CA based MAC protocol in @cite_17 implemented on physical hardware, as the base protocol with few additional modifications to its busy tone broadcasting scenarios. In this work, we extend the model in @cite_22 , which is an accurate analytical model of a saturated IEEE 802.11 DCF network with no hidden terminals, to the full-duplex medium access network with the presence of hidden terminals.
@cite_24 @cite_22 @cite_17 @cite_11
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In this paper, we present an experiment- and simulation-based study to evaluate the use of full duplex (FD) as a potential mode in practical IEEE 802.11 networks. To enable the study, we designed a 20-MHz multiantenna orthogonal frequency-division-multiplexing (OFDM) FD physical layer and an FD media access control (MAC) protocol, which is backward compatible with current 802.11. Our extensive over-the-air experiments, simulations, and analysis demonstrate the following two results. First, the use of multiple antennas at the physical layer leads to a higher ergodic throughput than its hardware-equivalent multiantenna half-duplex (HD) counterparts for SNRs above the median SNR encountered in practical WiFi deployments. Second, the proposed MAC translates the physical layer rate gain into near doubling of throughput for multinode single-AP networks. The two results allow us to conclude that there are potentially significant benefits gained from including an FD mode in future WiFi standards. In this paper, we consider the Medium Access Control (MAC) protocol design for full-duplex cognitive radio networks (FDCRNs). Our design exploits the fact that full-duplex (FD) secondary users (SUs) can perform spectrum sensing and access simultaneously, which enable them to detect the primary users' (PUs) activity during transmission. The developed FD MAC protocol employs the standard backoff mechanism as in the 802.11 MAC protocol. However, we propose to adopt the frame fragmentation during the data transmission phase for timely detection of active PUs where each data packet is divided into multiple fragments and the active SU makes sensing detection at the end of each data fragment. Then, we develop a mathematical model to analyze the throughput performance of the proposed FD MAC protocol. Furthermore, we propose an algorithm to configure the MAC protocol so that efficient self-interference management and sensing overhead control can be achieved. Finally, numerical results are presented to evaluate the performance of our design and demonstrate the throughput enhancement compared to the existing half-duplex (HD) cognitive MAC protocol. Full-duplex has emerged as a new communication paradigm and is anticipated to double wireless capacity. Existing studies of full-duplex mainly focused on its PHY layer design, which enables bidirectional transmission between a single pair of nodes. In this paper, we establish an analytical framework to quantify the network-level capacity gain of full-duplex over halfduplex. Our analysis reveals that inter-link interference and spatial reuse substantially reduces full-duplex gain, rendering it well below 2 in common cases. More remarkably, the asymptotic gain approaches 1 when interference range approaches transmission range. Through a comparison between optimal halfand fullduplex MAC algorithms, we find that full-duplex’s gain is further reduced when it is applied to CSMA based wireless networks. Our analysis provides important guidelines for designing full-duplex networks. In particular, network-level mechanisms such as spatial reuse and asynchronous contention must be carefully addressed in full-duplex based protocols, in order to translate full-duplex’s PHY layer capacity gain into network throughput improvement. Recent advances in antenna and circuit design enable radios that operate in full duplex mode on a single channel with very low residual self-interference. In this paper, the use of such full duplex radios in a wireless local area network (WLAN) is explored. Different scenarios in which the full duplex transmission can be exploited are studied. A distributed full duplex MAC design based on IEEE 802.11 DCF that adopts to the traffic conditions is proposed. The proposed MAC design works for both ad hoc and infrastructure modes of WLAN and takes into consideration new interference and contention during full duplex transmissions. OPNET simulations comparing the performance of the proposed MAC with traditional half duplex based IEEE 802.11 DCF show that the new MAC protocol provides up to 88 throughput gain in a heavily loaded network.