{'fraction_non_alphanumeric': 0.03308270676691729, 'fraction_numerical': 0.006015037593984963, 'mean_word_length': 5.278301886792453, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
RV-SFAMA-MA: RTS-VBF Algorithm Used in a Slotted-Based MAC Protocol for Underwater Acoustic Networks with an Acknowledgement Scheduling Algorithm

In recent years, spatio-temporal uncertainty has been a great challenge in the Media Access Control (MAC) protocol design for underwater acoustic networks (UANs). In this paper, a slotted based MAC protocol for UANs is proposed, called RV-SFAMA-MA, in order to solve the specific problems of UANs, such as long propagation, low channel utilization and luxurious underwater energy consumption. First, the sending time slot of the acknowledgment (ACK) control message is scheduled to avoid collision, and the appropriate ACK scheduling algorithm is selected by calculating the optimum capacity of UANs to solve the exposed terminal problem. Second, a multiple reception mechanism is introduced to improve the channel utilization, in which a novel RTS-VBF competition algorithm is proposed to determine the sending sequence of each node, so as to reduce the sum of network transmission delay and alleviate the funneling effect. The experiments show that compared with broadcast mac (BC-MAC) protocol and slotted floor acquisition multiple access (SFAMA) protocol, our RV-SFAMA-MA can achieve 25.44%-43.98% higher throughput and much lower energy consumption in a minitype UANs topology.