scholarly journals Design and Analysis of Handshake-Based MAC with Delay Variations in Underwater Acoustic Networks

Sensors ◽  
2019 ◽  
Vol 19 (19) ◽  
pp. 4159
Author(s):  
Chao Dong ◽  
Yankun Chen ◽  
Quansheng Guan ◽  
Fei Ji ◽  
Hua Yu ◽  
...  
Keyword(s):  
Propagation Speed ◽  
Propagation Delay ◽  
Medium Access ◽  
Underwater Acoustic ◽  
Slot Length ◽  
Wide Range ◽  
Acoustic Networks ◽  
Underwater Acoustic Networks ◽  
Delay Variations ◽  
The Impact

The long propagation delay in underwater acoustic channels has attracted tremendous attentions in designing Medium Access Control (MAC). The low acoustic propagation speed and wide area of the acoustic communication range led to a wide range of variations in the propagation delay. This paper identifies an important characteristic of two-scale delay variations by field test results. We carry out simulations to study the impact of delay variations on MAC, and the results suggest a slot length adaptation scheme for the handshake and slotting based MAC. We further model an absorbing Markov chain to derive the closed-form equation for the throughput of MAC with adaptive slot length. Both the analytical and simulation results show that our proposed slot length adaptation improves significantly the throughput of MAC in underwater acoustic networks. Particularly, the Slotted-FAMA with an adaptive slot length achieves more than double the throughput than the Slotted-FAMA with a fixed slot length in a network with six nodes.

scholarly journals An Efficient Topology Discovery Protocol with Node ID Assignment Based on Layered Model for Underwater Acoustic Networks

Sensors ◽  
2020 ◽  
Vol 20 (22) ◽  
pp. 6601
Author(s):  
Ruiqin Zhao ◽  
Yuan Liu ◽  
Octavia A. Dobre ◽  
Haiyan Wang ◽  
Xiaohong Shen
Keyword(s):  
Network Topology ◽  
Propagation Delay ◽  
Topology Discovery ◽  
Short Delay ◽  
Underwater Acoustic ◽  
Network State ◽  
Packet Collision ◽  
Initial Network ◽  
Acoustic Networks ◽  
Underwater Acoustic Networks

Underwater acoustic networks are widely used in survey missions and environmental monitoring. When an underwater acoustic network (UAN) is deployed in a marine region or two UANs merge, each node hardly knows the entire network and may not have a unique node ID. Therefore, a network topology discovery protocol that can complete node discovery, link discovery, and node ID assignment are necessary and important. Considering the limited node energy and long propagation delay in UANs, it is challenging to obtain the network topology with reduced overheads and a short delay in this initial network state. In this paper, an efficient topology discovery protocol (ETDP) is proposed to achieve adaptive node ID assignment and topology discovery simultaneously. To avoiding packet collision in this initial network state, ETDP controls the transmission of topology discovery (TD) packets, based on a local timer, and divides the network into different layers to make nodes transmit TD packets orderly. Exploiting the received TD packets, each node could obtain the network topology and assign its node ID independently. Simulation results show that ETDP completes network topology discovery for all nodes in the network with significantly reduced energy consumption and short delay; meanwhile, it assigns the shortest unique IDs to all nodes with reduced overheads.

MAP-NPS: A Novel Media Access Protocol Based on Node Pair Sequencing for Underwater Acoustic Networks

2014 ◽  
Vol 568-570 ◽  
pp. 561-567
Author(s):  
Sheng Quan Wang ◽  
Da Jun Sun ◽  
You Wen Zhang
Keyword(s):  
Mac Protocol ◽  
Propagation Delay ◽  
Media Access ◽  
Access Protocol ◽  
Underwater Acoustic ◽  
Node Pair ◽  
Hidden Terminals ◽  
Acoustic Networks ◽  
Underwater Acoustic Networks

In this paper, we propose and analyze an new MAC protocol based on node pair sequencing (MAP-NPS), which requires node pairs achieved successful handshakes to realize multiple transmissions orderly after one-off RTS-CTS competition. We analyze and assess the protocol’s performance via simulations. Compared to the MACA-U [1] protocol and the PCAP [2] protocol, we show that the new protocol have better performance,which can improve throughput, decrease the propagation delay and reduce hidden terminals and exposed terminals.

scholarly journals Concurrent Transmission Based on Distributed Scheduling for Underwater Acoustic Networks

Sensors ◽  
2019 ◽  
Vol 19 (8) ◽  
pp. 1871 ◽  
Author(s):  
Jun Zhang ◽  
Hanhua Lai ◽  
Yan Xiong
Keyword(s):  
Scheduling Algorithm ◽  
Average Energy ◽  
Propagation Delay ◽  
Distributed Scheduling ◽  
Medium Access Control Protocols ◽  
Underwater Acoustic ◽  
Transmission Cycle ◽  
Deterministic Scheduling ◽  
Acoustic Networks ◽  
Underwater Acoustic Networks

Handshaking is a common technique used to avoid collisions in terrestrial and underwater content-based networks. However, due to the long propagation delay of the underwater acoustic channel, the conventional handshaking mechanism, which only allows one successful handshake and one pair of nodes to communicate per transmission cycle, becomes less effective in underwater acoustic networks. This paper proposes a new distributed scheduling method for underwater acoustic networks that supports multiple handshakes and concurrent transmissions in one transmission cycle for one-hop clusters. A deterministic scheduling algorithm was developed to optimize the sending sequence and time of the source nodes jointly so that the total data transmission time is shortened while avoiding collisions among multiple concurrent transmissions. The deterministic scheduling algorithm can also reduce the scheduling overhead and enables the synchronization of the data concurrent transmissions in a distributed manner via the standard two-way handshaking. Simulation results show that the proposed method outperforms several conventional underwater medium access control protocols in normalized throughput, packet delivery rate, average end-to-end delay, and average energy consumption.

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