A peak detection based OOK photoacoustic modulation scheme for air to underwater communication

An Efficient Pulse Position Modulation Scheme to Improve the Bit Rate of Photoacoustic Communication

“…Therefore, in our frame design we have used M = 4. When 1.0 ms and M = 4, Figure 8 shows that the bit rate gain of our proposed PPM modulation is 3.2 times higher than the OOK modulation; this is indeed significant improvement in the achievable bit rate over our previously published OOK based modulation [19].…”

“…Hence, special techniques need to be employed for handling such hybrid PA signals. Secondly, the generated acoustic signal in the PA process is very broadband [19], which makes it very difficult to implement any kind of FSK or PSK modulation. Third and most important factor is the generation of vapor clouds near the laser light focus point on the water.…”

“…In other words, the vapor cloud limits the maximum repetition rate, i.e., maximum achievable bit rate using on-off keying modulation techniques. Recently, we have developed a peak detection based OOK modulation scheme for air-to-underwater non-linear PA communication [19]. Yet, the achievable bit rate through PDOOK is still constrained by the vapor cloud effect.…”

“…Little attention has been given to developing a suitable modulation scheme that handles the complexity of the hybrid signals; that is modulating a laser beam and demodulating the corresponding acoustic signal. Recently, we have developed a peak detection based OOK modulation (PDOOK) scheme to overcome this challenge [19]; yet the achievable bit rate using such an OOK-based modulation methodology is low. The bit rate limitation is attributed to the vapor cloud that is created by the laser beam underwater.…”

A Machine Learning based Investigative analysis for predicting critical temperature of superconductors

“…The critical temperature, denoted as T c , refers to the temperature at which certain metals, such as indium, mercury, lead, tin, and niobium, cease to exhibit electrical resistance [2]. The current analytical models used to predict the superconducting threshold temperature T c utilized to accurately ascertain the location of underwater sensor nodes by utilizing optoacoustic signals [6][7][8]. The traditional method of trial-and-error experimentation for discovering new superconductors is timeconsuming and requires the use of very high pressure and low temperatures.…”