In order to reduce the maintenance cost of structured Peer-to-Peer (P2P),Clone Node Protocol (CNP) based on user behavior is proposed.CNP considers the regularity of user behavior and uses the method of clone node.A B...In order to reduce the maintenance cost of structured Peer-to-Peer (P2P),Clone Node Protocol (CNP) based on user behavior is proposed.CNP considers the regularity of user behavior and uses the method of clone node.A Bidirectional Clone Node Chord model (BCNChord) based on CNP protocol is designed and realized.In BCNChord,Anticlockwise Searching Algorithm,Difference Push Synchronize Algorithm and Optimal Maintenance Algorithm are put forward to increase the performances.In experiments,according to the frequency of nodes,the maintenance cost of BCNChord can be 3.5%～32.5% lower than that of Chord.In the network of 212 nodes,the logic path hop is steady at 6,which is much more prior to 12 of Chord and 10 of CNChord.Theoretical analysis and experimental results show that BCNChord can effectively reduce the maintenance cost of its structure and simultaneously improve the query efficiency up to (1/4)O(logN).BCNChord is more suitable for highly dynamic environment and higher real-time system.展开更多
In Cognitive Radio(CR)networks,there is a common assumption that secondary devices always obey commands and are under full control.However,this assumption may become unrealistic for future CR networks with more intell...In Cognitive Radio(CR)networks,there is a common assumption that secondary devices always obey commands and are under full control.However,this assumption may become unrealistic for future CR networks with more intelligent,sophisticated and autonomous devices.Imperfect spectrum sensing and illegal behaviour of secondary users can result in harmful interference to primary users.In this paper,we propose a novel concept of Proactive-Optimization CR(POCR)networks,in which highly intelligent secondary users always try to proactively consider potentially harmful interference when making their behaviour decision.Furthermore,we propose an optimal transmission behaviour decision scheme for secondary users in POCR networks considering the possible harmful interference and penalties from primary users.Specifically,we formulate the system as a Partially-Observable Markov Decision Process(POMDP)problem.With this formulation,a low-complexity dynamic programming framework is presented to obtain the optimal behaviour policy.Extensive simulation results are presented to illustrate the significant performance improvement of the proposed scheme compared with the existing one that ignores the proactive-optimization of secondary users.展开更多
基金supported by the National Natural Science Foundation of China under Grant No.61100205Science and Technology Project of Beijing Municipal Education Commission under Grant No.KM201110016006Doctor Start-up Foundation of BUCEA under Grant No.101002508
文摘In order to reduce the maintenance cost of structured Peer-to-Peer (P2P),Clone Node Protocol (CNP) based on user behavior is proposed.CNP considers the regularity of user behavior and uses the method of clone node.A Bidirectional Clone Node Chord model (BCNChord) based on CNP protocol is designed and realized.In BCNChord,Anticlockwise Searching Algorithm,Difference Push Synchronize Algorithm and Optimal Maintenance Algorithm are put forward to increase the performances.In experiments,according to the frequency of nodes,the maintenance cost of BCNChord can be 3.5%～32.5% lower than that of Chord.In the network of 212 nodes,the logic path hop is steady at 6,which is much more prior to 12 of Chord and 10 of CNChord.Theoretical analysis and experimental results show that BCNChord can effectively reduce the maintenance cost of its structure and simultaneously improve the query efficiency up to (1/4)O(logN).BCNChord is more suitable for highly dynamic environment and higher real-time system.
基金supported in part by the National Natural Science Foundation of China under Grants No. 61101113,No. 61072088,No.61201198the Beijing Natural Science Foundation under Grants No. 4132007,No. 4132015,No. 4132019the Research Fund for the Doctoral Program of Higher Education of China under Grant No. 20111103120017
文摘In Cognitive Radio(CR)networks,there is a common assumption that secondary devices always obey commands and are under full control.However,this assumption may become unrealistic for future CR networks with more intelligent,sophisticated and autonomous devices.Imperfect spectrum sensing and illegal behaviour of secondary users can result in harmful interference to primary users.In this paper,we propose a novel concept of Proactive-Optimization CR(POCR)networks,in which highly intelligent secondary users always try to proactively consider potentially harmful interference when making their behaviour decision.Furthermore,we propose an optimal transmission behaviour decision scheme for secondary users in POCR networks considering the possible harmful interference and penalties from primary users.Specifically,we formulate the system as a Partially-Observable Markov Decision Process(POMDP)problem.With this formulation,a low-complexity dynamic programming framework is presented to obtain the optimal behaviour policy.Extensive simulation results are presented to illustrate the significant performance improvement of the proposed scheme compared with the existing one that ignores the proactive-optimization of secondary users.
