Power control for underwater acoustic MC-CDMA communication networks using the improved PSO algorithm

A Signaling-Free Underwater Code Division Multiple Access Scheme

“… is calculated to be 67 dB re 1 μpa using Equation (7). Meanwhile, the measured receiving power at node X, rcv X P , which depends on the node distribution, is ≈74 dB re 1 μpa.…”

“…We note that this value is chosen based on the range of the power spectral density of ambient underwater noise, which is from 60 to 100 dB re 1 µpa/Hz [4]. Then, the expectation E P rcv X←Y is calculated to be 67 dB re 1 µpa using Equation (7). Meanwhile, the measured receiving power at node X, P rcv X , which depends on the node distribution, is ≈74 dB re 1 µpa.…”

“…Code division multiple access (CDMA) is a promising underwater MAC scheme and has been intensely studied because of its advantages such as robustness against frequency-selective fading and high frequency-reuse efficiency [5,6]. Thus, the CDMA studies have been mainly focused on spread code assignment, power control, and energy efficiency [7][8][9][10][11]. In [12,13], code assignment and power control schemes for a transmitter-based CDMA system were proposed to achieve high network throughput, low energy consumption, and limited channel access delay in deep underwater communications.…”