Interference (wave propagation)

About: Interference (wave propagation) is a research topic. Over the lifetime, 26086 publications have been published within this topic receiving 321110 citations.

Interference aware (IA) MAC: an enhancement to IEEE802.11b DCF

Abstract: The IEEE802.11 has been devised explicitly for low mobility and single access point scenarios, so its effectiveness is impaired in conditions with not negligible interference in ad hoc and/or in infrastructure modes. Well known problems typical of these scenarios are the so called hidden and exposed terminals. In this paper we propose and test a novel MAC layer for wireless LANs, able to improve the performance of IEEE802.11 DCF (distributed coordination function) in environments with high interference levels. The key point is to insert information about received power and interference levels into MAC control packets. By computing an estimation of the interference increasing due to an eventual transmission (forbidden with IEEE802.11 because blocked by the virtual carrier sensing), the number of parallel transmissions can grow significantly.

Interference Impact on Coverage and Capacity for Low Power Wide Area IoT Networks

Abstract: In this paper we analyze and discuss the coverage and capacity of Sigfox and LoRaWAN in a large scale urban environments covering 150 km$^2$ in Northern Denmark. First, the study measures and analyzes interference in the European 868 MHz license free industrial, scientific, and medical band, creating a model for the interference. The measured interference in downtown Aalborg has an occurrence rate of 22 % and a generalized extreme value distributed power level. Next, the study compares the coverage of the two Internet of Things network solutions using the existing Telenor cellular site grid both with and without interference from the measured external sources. The study concludes that without interference, both LoRaWAN and Sigfox provides very good indoor coverage of more than 99 %. Furthermore, Sigfox and LoRaWAN can provide uplink and downlink failure rates of less than 1 % for the 95 percentile of the devices for all cells without external interference. Adding the external interference results in an outdoor coverage of 90- 95 % and indoor coverage of 50-80 %. Finally, the uplink and downlink 95 percentile failure rate increases significantly to 50 % for LoRaWAN and exceeds 60 % for Sigfox.

Experimental statistical signature of many-body quantum interference

Abstract: Multi-particle interference is an essential ingredient for fundamental quantum mechanics phenomena and for quantum information processing to provide a computational advantage, as recently emphasized by boson sampling experiments. Hence, developing a reliable and efficient technique to witness its presence is pivotal in achieving the practical implementation of quantum technologies. Here, we experimentally identify genuine many-body quantum interference via a recent efficient protocol, which exploits statistical signatures at the output of a multimode quantum device. We successfully apply the test to validate three-photon experiments in an integrated photonic circuit, providing an extensive analysis on the resources required to perform it. Moreover, drawing upon established techniques of machine learning, we show how such tools help to identify the—a priori unknown—optimal features to witness these signatures. Our results provide evidence on the efficacy and feasibility of the method, paving the way for its adoption in large-scale implementations. An experimental protocol to discern true multi-particle interference is demonstrated in a boson sampling device without dynamic reconfiguration. Statistical features of three-photon interference were evaluated in a seven-mode integrated interferometer.