What’s this paper all about?

Chirps are signals with a time-varying frequency, which can also be found in nature. Ultrasound chirps, for instance, are employed by bats to locate themselves through their echoes and many bird sounds are actually acoustic chirps. In technology, similar signals using electromagnetic waves are already extensively used for radar systems, but their application in wireless communications is also considered. However, the majority of currently proposed chirp-based communications systems only achieve a very low bit rate, since the whole chirp duration is reserved for one or two bits. This paper explores the possibility that we can overlap many chirps in time to transmit many more bits within one chirp duration, and thus increase the data rate, improving the efficiency of the system.

What exactly have you discovered?
If we transmit many chirp signals in a chirp duration by overlapping them, then they will interfere with each other. In this paper, we have figured out the effect of the interference caused by the overlapping and we have proposed methods to compensate for this interference.

So what?
Utilizing our methods, the bit rate of the chirp-based systems can increase tenfold or more in comparison with the existing methods, while retaining low bit loss rate. The final goal is to employ these chirps for both communications and radar, allowing us to design a single system that not only allows radar detection but also efficient communications for the next generation of wireless communications in 6G.

Want to learn more? 
Thuy M. Pham ; André N. Barreto ; Gerhard P. Fettweis (2020). Efficient Communications for Overlapped Chirp-based Systems. IEEE Wireless Communications Letters. Read the full paper here.