A Joint Relay Selection and Power Allocation MAC Protocol for Underwater Acoustic Sensor Network

Abstract

Different from the mechanism of medium access control (MAC) for the land-based sensor networks, the underwater acoustic sensor network faces problems such as high propagation delay, spatial-temporal uncertainty and high energy consumption. Orthogonal frequency division multiple access (OFDMA) is a channel access mechanism based on OFDM multi-carriers modulation technology. In OFDMA, multiple users can make use of the orthogonality of the subchannels to simultaneously access channel for parallel transmission. For underwater multi-hop network scenario, this paper proposes a MAC protocol of the joint relay selection and power allocation (JRSPA-MAC) based on OFDMA mechanism. The proposed protocol is divided into flowing phases: Firstly, the node determines the hop distance from the sink nodes and sends the request when there are packets to be sent. Then forwarding nodes election algorithm is proposed based on the channel condition and the delay information. On this basis, the sending nodes autonomously use the particle swarm optimization (PSO) algorithm to allocate its subchannels' power. Secondly, taking advantage of the high underwater acoustic propagation delay, the receiving node reasonably schedule the sending time, makes sure the parallel communication of multiple pairs of nodes in one handshake period. Finally, the destination nodes and the forwarding nodes acknowledge the received packets and completes this data transmission. The simulation results show that compared with the handshake based MAC protocols, the JRSPA-MAC reduces the probability of packet loss caused by data conflicts between nodes. In case of low power consumption, the network throughput are effectively improved, and the average end-to-end delay of the network is reduced. INDEX TERMS Spatial-temporal uncertainty, relay selection, PSO, power allocation, OFDMA.

Optimization Techniques in Cooperative and Distributed MAC Protocols

“…Relay selection, power allocation are two methods in which path of packets transmission is identified and nodes selection algorithm is applied to reduce uncertainty, propagation delay and energy consumption. Sending nodes use PSO algorithm, receiving nodes see that multiple pairs communicate with single handshake taking advantage of high propagation delay in underwater networks and in turn reduce delay, power consumption and packet loss and improve throughput (Su, Y. et al, 2020). Cluster head selection and multi-hop using LEACH protocol and cat based salp swarm algorithm with taylor series helps in addressing energy consumption and delay problems.…”

Hybrid Space-Frequency Access for Underwater Acoustic Networks

“…In fact, SNR is essentially considered to be function of the attenuation on the first signal component arrival [33]. Second, a single-tap impulse response is typically the result of channel equalization performed at the receiver [34], [35], [36]. In this direction, communication performance can be reliably evaluated as a function of the SNR rather than the channel impulse response [37], [38].…”

An Energy-Efficient MAC Protocol for Three-Dimensional Underwater Acoustic Sensor Networks With Time Synchronization and Power Control

“…Besides, UASN needs to cover a large area of the ocean, which leads to the sparseness of node deployment. Furthermore, most nodes are powered by batteries with limited energy, making it difficult to supply energy [8]. Therefore, the design of the MAC protocol must be based on energy saving to effectively control power consumption.…”