Medium Access Control Protocols For Data Collection In Underwater Acoustic Sensor Networks

Underwater acoustic sensor networks(UASNs)have drawn increasing attention in recent years because of their wide applications.The design of an efficient Medium Access Control(MAC)protocol for UASNs is of great importance because the MAC protocol directly coordinates nodes'access to the the shared acoustic channel and finally impacts on the network performance.Under-water acoustic channels have many unique characteristics such as high propagation,low available bandwidth and high error rates.These unique characteristics pose great challenges in MAC proto-col design for UASNs.Taking the characteristics of UASNs into account,this paper designs two MAC protocols for data-collection-oriented UASNs.In order to alleviate the funneling effect in UASNs for data collection,we propose a slot-ted floor acquisition multiple access based MAC protocol for multi-hop UASNs with a multiple reception mechanism(SFAMA-MM).In SFAMA-MM protocol,a scheduling algorithm for the transmission of ACK packets is proposed to solve the exposed terminal problem in slotted floor ac-quisition multiple access(Slotted FAMA)protocol.Besides,a novel multiple reception mechanism is proposed to alleviate the funneling effect in UASNs for data collection.The multiple reception mechanism allows a receiver to receive data packets from multiple neighboring nodes during each round of handshake.Simulations show that the SFAMA-MM is able to achieve higher throughput and lower energy consumption compared to the Slotted FAMA protocol.In order to alleviate the funneling effect in data-collection-oriented UASNs and solve the problem that most contention based MAC protocol is incompatible with geo-routing protocols,we propose a vector-based forwarding and Slotted FAMA based cross-layer MAC protocol for multi-hop UASNs with a multiple reception mechanism(VBF-SFAMA-MM).VBF-SFAMA-MM protocol integrates the contention based MAC protocol Slotted FAMA protocol with the vector-based forwarding(VBF)routing protocol.By exchanging control packets,node can achieve the channel reservation and next-hop selection.Similar to SFAMA-MM protocol,a multiple reception mechanism is introduced to allow the sink to receive data packets from multiple neighboring nodes during each round of handshake to alleviate the funneling effect in data-collection-oriented UASNs.Simulations show that the VBF-SFAMA-MM is able to achieve higher throughput,lower energy consumption and lower end-to-end delay.