Opportunity Routing Mechanism In IoNT

In recent years,the continuous development of nano communication and nano network provides technical support for the Internet of things in the nano field.Many nano nodes combine to monitor the complex environment and transmit information to Internet gateway,which is the communication paradigm of nano Internet of things.This communication paradigm occupies an important advantage especially in the human cardiovascular detection system.However,there are important challenges in this kind of human health detection.Firstly,in the complex mobile environment,the movement of nodes increases the instability of network communication and reduces the link quality of data packets.Secondly,they do not have the position sensing devices such as GPS due to the size characteristics of nano nodes,they cannot locate the gateway nodes and determine the forwarding direction of data packets.Finally,the human body medium leads to high communication energy consumption and short nanonetwork life cycle without external charging.Therefore,in this paper,we propose Relative Position Awareness Based Opportunistic Routing Protocol(RPAOR)and Mobile Awareness Based Opportunistic Routing Protocol(MAOR)according to the application scenario of human cardiovascular system using the detection packet of the gateway node to identify relative position information by means of human blood flow guidance.The opportunistic routing mechanism is adopted to make full use of the advantages of wireless broadcasting.The transmission path of data packets is determined by the link quality to realize the reliable transmission of mobile network.We mainly studies the opportunistic routing mechanism in Io NT from the two aspects of Candidate Relays Selection(CRS)and optimization.Combined with the characteristics of nano-nodes and human cardiovascular application scenarios,the opportunity routing mechanism in Io NT is studied:1.In the CRS,gateway nodes send the detection packets periodically.RPAOR is proposed where CRS is based on the relative position information of nodes combined with the mobile characteristics of flow guided application scenarios.Then,nodes in candidate relays are sorted according to their own different parameters(energy capture rate,residual energy,relative position information).And the nodes that successfully receive the data packet broadcast the acknowledgment packets in priority order.The nodes receiving the acknowledgment packets in the candidate relays stop backing off and waiting for the acknowledgment packets to be sent.The simulation experiment is compared with the flooding and random protocols from four aspects: packet transmission success rate,throughput,transmission delay and transmission energy consumption.The experiment proves its superiority in the aspects of packet transmission success rate,transmission energy consumption and throughput.It has greater superiority in delay comparing with the random protocol.Compared with the flooding protocol,the advantage of the RPAOR protocol is not obvious because the backoff forwarding mechanism of the candidate relays set causes the transmission delay of the data packet.2.In order to improve the data transmission efficiency of the forwarding node and reduce the impact of node mobility on the transmission efficiency of RPAOR,we propose MAOR by optimizing the CRS.Due to the guidance of blood in the blood vessels of the human body,the nano-nodes as a whole move in a certain direction.However,the mobility of the human body,the impact and blocking of the cells make the movement of the nano-nodes instable and uniform.In order to obtain the motion state of the nano-node,we build a mobile gradient model on the basis of quantifying the relative position information of nodes and select nodes with better mobility as candidate relays.The relative position information of the nodes around the relay node is included in the CRS priority ranking criteria so that the candidate relay node which is closest to the gateway node in the candidate relays first forwards the data packet.Under the premise of meeting the mobility requirements,the MAOR protocol takes into consideration the distance factor and forwards the data packets.Through simulation experiments,it compares with the RPAOR,Random,and Flooding protocols in terms of packet transmission success rate,throughput,transmission delay,and transmission energy consumption.Delay,packet transmission success rate,and throughput are all dominant,but the energy consumption of the MAOR protocol has increased due to the establishment of the mobile gradient model,and the growth rate is faster as the node density increases.