Tham khảo tài liệu 'wireless sensor networks application centric design part 8', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | Modelling Underwater Wireless Sensor Networks 199 packet will include the information of the location of the sender the final receiver and the one of next hop of the packet. To be able to run this protocol it is assumed that every node have the capacity of measuring the distance and angle of arrival AOA of the signal. The route of the packet is compute in the sender and included in the packet. When a node receives a packet it calculates its relative position towards the target. This works recursively in all the nodes during the transmission. If the node knows that is close enough to the routing vector it will be under the threshold value established for this purpose it will include its position and forward the packet in other case it drops the packet. In this way all the packet forwarders in the sensor network form a routing pipe the sensor nodes in this pipe are eligible for packet forwarding and those which are out do not forward. Fig. 11. High Level view of VBR for UWSN. The figure represents the nodes that are within the routing pipe that forward the packet w the threshold used to measure the width of the pipe. And the nodes that are out of this path discard the packets. This protocol is scalable to the size of the network. This kind of forwarding path specified by the routing vector involving nodes for packet routing has as result the energy of the network. FBR Focus Beam Routing a routing protocol Jornet Stojanovic 2008 based on location is presented as a way to find the path between two nodes in a random deployed network. The figure 8 shows a simple two-dimensional network to explain the protocol although it works in the same way in three-dimensional scenarios. 200 Wireless Sensor Networks Application-Centric Design Fig. 12. Nodes within the transmitter s cone 0 are candidate relays. Assuming a communication between node A and node B node A will send and Request to Send RTS multicast message to all the reachable neighbours. This packet will include the .
