Underwater communication is one of the most important and difficult challenges facing researchers due to the high attenuation of the signal, communication with the surface because of the harsh medium of water, and data transmission performance degradation as a result of various effects. Underwater acoustic communication (UWA) has a low data rate, which describes the disadvantage of this type of communication. In addition, it has a low bandwidth range and high latency but has a long transmission range as an advantage. Multicarrier wireless transmission systems increase the data rate by sending the data using more than one carrier. We proposed a noncoherent orthogonal frequency division multiplexing (OFDM) method to increase the data rate in UWA communication systems. In addition, doubling the data rate in the OFDM using Subcarrier Power Modulation (OFDM-SPM) system can save half of the bandwidth. The MATLAB simulation program was used to implement the system in the underwater acoustic environment to increase its throughput. The proposed design uses Differential Phase Shift Keying (DPSK) with power control, and the data stream is transmitted through two-dimensional modulation schemes, the DPSK, and the power level of each subcarrier in the OFDM system with cyclic prefix (CP). The underwater channel was designed using a Rician fading multipath with a spreading loss formula as a function of distance and frequency. We designed an equalizer at the receiver side to recover the original signal as a function of three parameters which are: the channel effect as a rate between transmitting and receiving symbols, the Rician channel response, and the UWA spreading loss. OFDM-Subcarrier Power Modulation (OFDM-SPM) using the proposed equalizer performed better than the theoretical OFDM-SPM in the Rayleigh channel. The designed equalizer increased the performance of the OFDM-SPM system by 25% which helped to enhance the system’s throughput and doubled the data rate compared with the OFDM system, doubling the data rate using OFDM-SPM had been validated in laboratory experiments in the Time domain.

水下通信是研究人员面临的最重要和最困难的挑战之一，因为信号的高衰减、由于水介质的恶劣而与水面的通信以及由于各种影响而导致的数据传输性能下降。水声通信（UWA）的数据速率较低，这说明了此类通信的缺点。此外，它具有低带宽范围和高延迟，但具有传输范围长的优点。多载波无线传输系统通过使用多个载波发送数据来提高数据速率。我们提出了一种非相干正交频分复用 (OFDM) 方法来提高 UWA 通信系统的数据速率。此外，使用子载波功率调制 (OFDM-SPM) 系统将 OFDM 中的数据速率加倍可以节省一半的带宽。使用MATLAB仿真程序在水声环境中实现该系统以提高其吞吐量。所提出的设计使用具有功率控制的差分相移键控（DPSK），并且通过二维调制方案、DPSK以及具有循环前缀（CP）的OFDM系统中每个子载波的功率电平来传输数据流。水下信道是使用莱斯衰落多径设计的，其扩展损耗公式是距离和频率的函数。我们在接收器侧设计了一个均衡器，以将原始信号恢复为三个参数的函数，这三个参数是：信道效应（作为发送和接收符号之间的速率）、莱斯信道响应和 UWA 扩展损耗。使用所提出的均衡器的 OFDM 子载波功率调制 (OFDM-SPM) 在瑞利信道中的性能优于理论上的 OFDM-SPM。所设计的均衡器将 OFDM-SPM 系统的性能提高了 25%，这有助于提高系统的吞吐量，并且与 OFDM 系统相比，数据速率提高了一倍，使用 OFDM-SPM 实现数据速率加倍已在当时的实验室实验中得到验证。领域。