Non-line-of-sight (NLOS) and near-line-of-sight are radio transmissions across a path that is partially obstructed, usually by a physical object in the innermost Fresnel zone.
Many types of radio transmissions depend, to varying degrees, on line of sight (LOS) between the transmitter and receiver. Obstacles that commonly cause NLOS conditions include buildings, trees, hills, mountains, and, in some cases, high voltage electric power lines. Some of these obstructions reflect certain radio frequencies, while some simply absorb or garble the signals; but, in either case, they limit the use of many types of radio transmissions, especially when low on power budget.
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Deep-ultraviolet (DUV) light ranging from 200 to 280 nm, that is, a solar-blind region.
As the light source for nonline-of-sight (NLOS) communication, DUV light has the natural advantage of a negligible background due to strong ozone absorption. However, the existing DUV sources suffer from either low power or low modulation frequency.
246 nm with a record-high performance for NLOS communication, that is, a simultaneous continuous-wave output power of 430 mW and a modulation frequency of 5 MHz. Significantly, both the output power and the modulation frequency can be further improved when the horsepower of EBs is fully released. Not only does the proposed DUV source show great capability for NLOS communication