Long-Range Communication Performance based on Passive Phase Conjugation Impacted by Internal Waves in the South China Sea

Passive-phase conjugation (PPC), in a shallow water waveguide, the cross-correlation of impulse response and the impulse response immediately after, can be utilized as the channel equalizer to enhance the communication performance. PPC is more practical and simpler than Time Reversal Mirror (TRM) since the back propagation is simulated, instead of using source receiver array transmitting backward. This paper addresses the long range (32 km) communication performance based on PPC with the 100 bps BPSK modulation scheme. At- sea data analysis and simulations are performed to attribute to the maximum bit rate, bit error rate, phase shift and the optimum performance of PPC. The results show the realization of PPC is affected by the number of receivers and existent acoustic modal structure, which fluctuate due to the large-amplitude internal waves and a range- dependent, shoaling bathymetry.