Wireless devices are ubiquitous nowadays and, since most of them use the same unlicensed frequency bands, the high number of packet losses due to interference and collisions degrade performance. Reliability, energy consumption, and latency are key challenges for future dense networks. Allowing the transmitter to take action, i.e., vacating the channel, as soon as a collision or interference is detected is crucial in improving these metrics. In-band full duplex radios enable the transmitter to simultaneously transmit packets and sense the spectrum for collisions and interference. This paper studies two important questions regarding transmitter-based collision and interference detection: (1) from an overall system perspective, does such detection outperform receiver-based detection and (2) which test statistic is the most accurate and sensitive at detecting collisions and interference. First, NS-3 simulations are used to show that transmitter-based detection reduces the energy consumption while improving the throughput in a typical star topology network. Next, we present a measurement-based study of four different techniques for transmitter-based collision and interference detection. In particular, we compare the energy detector with three goodness-of-fit tests in terms of probability of detection and false alarm. Our analysis shows that transmitter-based detection can detect between 80% to 100% of the collisions and interference occurring at the receiver, depending on the distance between the transmitter and the receiver. Of those detectable by the transmitter, our measurement results show that goodness-of-fit tests can detect nearly 100% of the collisions and have at least 10 dB better sensitivity as compared to the commonly proposed energy detection test. In general, the proposed techniques can detect interfering signals that are up to 25 dB below the remaining self-interference power.

The densification of wireless networks that contend for a shared medium, demands improved MAC solutions that can reduce the energy cost of packet collisions. In this paper we analyze a novel in-band full duplex collision and interference detection scheme for dense networks, studying the energy savings that it can bring with respect to the performance of half duplex communications. Under a high external interference scenario, results show that the proposed full duplex scheme is more energy-efficient than half duplex transmissions for any network density. When the interference is low, the full duplex scheme provides energy gains when the number of contending devices is above a critical value. Expressions for calculating this critical number of devices are provided, showing that it is smaller when the likelihood of collisions increases. In the studied cases, results show the energy savings grow exponentially with the density of the network.

Full duplex wireless communication is a promising new technique that enables the simultaneous transmission and reception of a packet on the same frequency. Until now most research focused on proving the feasibility of full duplex Wi-Fi systems, focusing mainly on PHY layer analysis of the BER or PER. In this paper, the use of full duplex in wireless sensor networks is analysed, and it is shown that this can enable significant energy and delay gains, even when considering a realistic MAC protocol. This paper presents a novel full duplex energy model and MAC protocol for wireless sensor networks, compatible with realistic 802.15.4 chips and the standard MAC protocol. We show the potential of full duplex sensor networks, both for networks with low and high loads. Especially for high loads, full duplex enables a promising collision detection, avoiding wasting scarce resources in long packet collisions. Full duplex nodes outperform half duplex nodes both in terms of energy as in terms of delay, even in case of asymmetric traffic conditions. In addition, several advantages exist in terms of fairness of downlink traffic towards uplink traffic.