Enhanced Fully Generalized Spatial Modulation for the Internet of Underwater Things

Abstract

A full design of the Internet of Underwater Things (IoUT) with a high data rate is one of the greatest underwater communication difficulties due to the unavailability of a sustainable power source for the battery supplies of sensor nodes, electromagnetic spread weakness, and limited acoustic waves channel bandwidth. This paper presents a new energy-efficient communication scheme named Enhanced Fully Generalized Spatial Modulation (EFGSM) for the underwater acoustic channel, where the different number of active antennas used in Fully Generalized Spatial Modulation (FGSM) is combined with multiple signal constellations. The proposed EFGSM enhances energy efficiency over conventional schemes such as spatial modulation, generalized spatial modulation, and FGSM. In order to increase energy and spectral performance, the proposed technique conveys data bits not just by the number of active antenna's index as in the existing traditional FGSM, but also using the type of signal constellation to increase the data bit rate and improve power saving without increasing the receiver’s complexity. The proposed EFGSM uses primary and secondary constellations as indexes to carry information, they are derived from others by geometric interpolation signal space. The performance of the suggested EFGSM is estimated and demonstrated through Monte Carlo simulation over an underwater acoustic channel. The simulation results confirm the advantage of the suggested EFGSM scheme not just regarding energy and spectral efficiency but also concerning the average bit error rate (ABER).

Pilot-Based Adaptive Channel Estimation for Underwater Spatial Modulation Technologies

“…Recently, the FGSM [15] and EFGSM [39] have been proposed to the UWA channel to improve the energy loss of the underwater sensor network. The transmission vector of the SMTs-MIMO is transmitted over underwater time-varying MIMO channel with an AWGN.…”

“…The SMTs have been applied for the UWA channel in [15,39] considering the full channel information at the receiver side. Unfortunately, the UWA channel is hard to adequate estimate; in this section we will address the UWA features.…”

Deep Learning-Based Spread-Spectrum FGSM for Underwater Communication

“…Underwater acoustic communication (UWAC) has become one of the critical research fields due to its proliferation of new scientific, industrial, and naval applications [1][2][3]. However, the limitation of the available bandwidth, poor physical link quality, availability of a sustainable energy source for the battery feed sensor nodes, high latency, and attenuation of the acoustic waves by water still represent the main drawbacks of the wireless communication in the ocean's environment [3][4][5].…”

“…Underwater acoustic communication (UWAC) has become one of the critical research fields due to its proliferation of new scientific, industrial, and naval applications [1][2][3]. However, the limitation of the available bandwidth, poor physical link quality, availability of a sustainable energy source for the battery feed sensor nodes, high latency, and attenuation of the acoustic waves by water still represent the main drawbacks of the wireless communication in the ocean's environment [3][4][5]. Although optical communication, electromagnetic communication, and magnetic induction communication can be employed for the oceanic environment, acoustic communication is considered to be the widest in use since it achieves long communication distances of tens of kilometers for the low data transmission rate and several tens of meters for the high data transmission rate [6,7].…”

“…Researchers provided different SMTs schemes to improve the performance of SM [13,14] by emitting the constellated data symbols using multiples antenna [15][16][17], or separating the real and imaginary parts of the constellated data symbol and then transmitting them via one or more transmit antennas [18][19][20]. Some others tried inserting additional dimensions represented by another type of signal constellation to be used as an index and information-bearing [3,12,21].…”