Traditional coding technologies for the transmission of information use a binary system. In this case, even the currently developing methods of quantum information transfer are also based on a data system with two variables. Although methods of multidimensional quantum coding are "capable of more". And theoretically possible four-dimensional coding not so long ago for the first time passed a series of tests.

The new development allows each photon to carry one of four values ??- 00, 01, 10 and 11. The very use of the technology of the so-called quantum 4D-coding allows to increase the amount of transmitted information several times, and the data itself have a much higher level of protection from both interception of data and other external factors.

Until recently, quantum 4D-coding technologies were implemented only in the form of small models, but experts from the University of Ottawa successfully conducted the first real tests. The transfer of information was carried out between base stations located on the roofs of high-rise buildings at a distance of 300 meters from each other.

Both stations were placed inside wooden boxes, protecting them from bad weather conditions. The error rate for data transmission was 11%, which is much lower than the level required for the organization of a secure quantum communication channel. The system was able to transmit 1.6 times more information than the system with "ordinary" quantum coding. As lead researcher Ibrahim Karimi stated, "Our experiment was the world's first data transmission, conducted using multidimensional quantum coding technology in real urban conditions. The quantum communication system demonstrated by us, operating in the open air, is able to provide communication with satellites in orbit and places on the Earth's surface, where it is inappropriate to lay optical fiber. Such a system can also serve to organize a secure connection with moving objects, such as aircraft and ships. In the future, we plan to increase the distance to 5.6 kilometers using intermediate stations and an adaptive optics system that will compensate for all distortions introduced by the atmosphere ".