Research On Multi-hop Transmission And Networking For Quantum Communication Network

Quantum communication,combining quantum mechanics and traditional communication theory,has attracted attention both in China and the world for high safety and potential efficiency.Now,quantum communication is gradually developing from theoretical and experimental studies to practicality and engineering.Quantum communication includes quantum teleportation,quantum dense coding and quantum private communication,etc.Using quantum entanglement as communication resource,this paper study multi-hop transmission in long distance communication,and how to deploy the entanglement sources in quantum communication networks.Research on multi-hop transmission in quantum communication network.First,one-hop quantum teleportation scheme is proposed to transmit arbitrary two-qubit state,which uses GHZ state and Bell state to construct the GHZ-Bell quantum channel.However,since the channel loss limits the communication efficiency and distance,this paper introduces intermediate nodes to build multi-hop quantum path to solve the problem of long-distance communication.During multi-hop transmission,source and intermediate node could perform the entanglement measurements and transmit results in parallel.After collecting all the measurement outcomes at the destination node,an efficient method is proposed to calculate and perform the unitary operations for transforming the receiver's states to the state teleported.From the transmission performance analysis,multi-hop scheme can reduce transmission delay and save transmission overhead compared with hop-by-hop transmission.Research on networking for quantum communication network.In order to improve the connectivity of the network,this paper provides two optimization algorithms to deploy entanglement sources after analyzing and establishing the mathematical model of the quantum communication network.A deployment algorithm based on node position(DNP)improves connectivity by guaranteeing that all overlapping areas of the distribution ranges of the entanglement sources contain nodes.In addition,a deployment algorithm based on an improved genetic algorithm(DIGA)is implemented by dividing the region into grids.From the simulation results,DNP and DIGA improve quantum connectivity by 213.73%and 248.83%compared to random deployment,respectively.Both algorithms achieve higher connectivity.Therefore,this paper mainly presents a multi-hop teleportation protocol based on GHZ-Bell quantum channel for two nodes without directly sharing entanglement pairs,and designs optimization algorithms to deploy entanglement sources for improving the network connectivity,which improve the transmission efficiency of quantum communication network.