The external environment The user demands The user demands The internal environment Figure 1. The environment range that communication network sensed Stage one: the network senses current network (SLA), making the reasonable and correct response to theenvironments, including external and internal environments. new user demands. Each node in the communication network can onlymonitor the local network state information, how to make III. THE RESEARCH STATES OF COGNITIVEeach node know the whole network state information is a COMMUNICATION NETWORKproblem to be solved firstly. Driven by the process of information globalization, aStage two: the communication network is clearly aware large lots of research works on the communication networkof the current demands and the occupied network technology were carried out. The U.S. National Scienceresources of various users. Foundation provided 3 billion for the supporting of 100 × How to dynamically obtain the global information of the 100, FIND and GENI projects. In Europe, the financialoccupied network resources, and make the communication supports more than 9.1 billion Euro was afforded to thenetwork rapidly estimating the usages of network resources, researches of ICT (information and communicationis another great challenge. technology). In China, the National High-Tech. R&DStage three: dynamically allocates the resources and Program and 973 Program afforded to the researches on thisreconfigures the network adapting to the demands of new kind of communication network technology, and takes itusers with the correct and reasonable response.. as an important direction in information areas, considering the technologies of cognitive communication network and reconfiguration as the hot spots problems. Overall, the U ser dem ands present researches on the cognitive communication network are mostly about the exploratory on cognitive capabilities, and are still in its infancy. The cognitive communication environments environments network technology is still an open issue, and the main External Internal Learning and intelligent decision research projects are as follows: (1) The Cognitive Networking (CogNet) Project funded by the U.S. National Science Foundation (NSF) The Future Internet Design (FIND) is a long-term M anagem ent and control of research project afforded by U.S. NSF in 2004. The goal of netw ork resources FIND is to achieve the next generation Internet, and its core features include: security, robustness, manageability, the new Reconfigurable computing model, integration of new network technology, netw ork elem ents high standards of service architecture and the new network architecture theories. The Global Environment for Network Figure 2 the cognitive technology of communication Innovation (GENI) is officially announced in August 2005 network by U.S. NSF as an action plan. The goal of GENI is to build a test bed to accommodate a variety of new architecture, and Communication network will be based on the sensed explore the framework more suitable for the futurenetwork environments, user demands, and the occupied computing environment. The researches of GENI include:network resources, the communication network does some rethinking the functions of network; designing new networknecessary reconfiguration based on the Services Agreement architecture and services; designing the key capacity of
network security and new supporting technologies. As part IV. THE ARCHITECTURE AND TECHNOLOGIES FORof the FIND and GENI plan, the main goal of cognitive COGNITIVE COMMUNICATION NETWORKSNetworks technology is to design and achieve the cognitivenetwork architecture and protocols, develop the prototype 4.1 The architecture of cognitive communicationsystem of cognitive network protocol stack, and its main networkswork include: As shown in Figure-3, the cognitive communication networks is composed three parts, including the demands Adaptive physical layer and programmable media mapping and policies generating unit, the network cognitiveaccess control (MAC) layer; and reconstruction unit and the programmable Adaptive frequency readjusting protocol for communication network.transmission link; The demands mapping and policies generating unit: On Unified control layer for monitoring, configuring, and the one hand mapping the demands from different users intoadjusting the data layer module; different end-to-end network goals (specific network behavior), on the other hand merging the local network Intelligent network layer protocol for the functions of environmental information sensed from the underlyingtopology discovery, service discovery, addressing, communication network to form the global network resourcenaming and dynamic routing. information, and then generating the necessary network (2) The software programmable intelligent network reconfiguration policies based on the relevant service level(SPIN) project in Stanford University agreements (SLA). The number of the policies generating Stanford University proposed the software programmable unit in the network is in small quantities, and can beintelligent network (SPIN) concept, based on the 9 kinds of deployed in central or distributed pattern.basic problems existing in the current IP networks, and The network cognitive and reconstruction unit: On theextracted the advantages in the architecture of IP networks, one hand completing the sensing of network environment,PSTN, cellular networks and ad hoc networks to form a including network topology, the transmission link status,novel network architecture. The SPIN is essentially a network node state information, network security status, andnetwork operating system, with the similar status as the geographical and meteorological information, which areoperating systems in computer, and possesses a 3-layer translated into the local sensing information by the cognitivestructure including the transport layer, the control and specification language as the input of the demands mappingmanagement layer and the cognitive layer. and policies generating unit; on the other hand, translating (3) The MotoMeshTm test-bed network by Motorola the network reconfiguring policies from the demandsCorporation mapping and policies generating unit into the network The main research area for Motorola Corporation in configuration parameters through the cognitive specificationcognitive networks is the MotoMeshTM test-bed network language, completing the work of network resourcewith the ability of end-to-end reconfiguration. The project allocating and connection managing. The number of theincludes 27 top U.S. universities, equipment providers, network cognitive and reconstruction unit in network is large,network operators, and standards and policy makers. Its goal corresponding to the cognitive and reconfiguring node.is to design, develop and test a new network architecture, to The programmable communication network is consists ofguide the design of reconfigurable transmission equipment, the programmable configuration elements (links, nodes, etc.)network equipment and supporting systems. and the network status sensors, and the programmable (4) The Wireless Network After Next (WNaN) project by configuration elements are the control points of cognitiveDARPA network, as well the network status sensors completing the 2009, the Defense Advanced Research Projects Agency sensing work of the network status.(DARPA) started the Wireless Network After Next (WNaN) 4.2 The Technologies of cognitive communicationproject, based on the XG project and adaptive network networkstechnology, aiming to develop the quickly cognitive-based Part of the network nodes and links in cognitivenetwork construction technology for the battlefield communication network possess the learning and reasoningenvironment, lower cost of network equipment and handheld ability, and can dynamically make decision and reconfigurewireless terminals, covering a wide range of connections for the network elements, by measuring or predicting theeach soldier. June 2009, the BBN Corporation in United network environmental parameters, to meet the targets ofStates won the finance of 1100 million for the development self-adapting network environment, optimal use of networkof this network project. resources (Frequency, the link bandwidth, node processing power, etc.) and optimizing the performance of end-to-end information transferring. Its technologies include:
User demands End-to end goals Demands mapping Service priority policy Delay-control policy Transmission Bandwidth-control demands mapping and Global network protecting policy policy policies generating information Network environment Policies Other policies generating Cognitive Specification Language-CPL Topology info Network resources configuration and management Network Link states info sensing control network cognitive and reconstruction Node configuring Dynamic resource Security Connection and states info allocation management management Security states Geographical and meteorological info programmable communication network Figure-3 the architecture of cognitive network (1) The rapid sensing technologies of communication mapping technologiesnetwork environment The network resources dynamically allocating The rapid measuring technologies of network technologiesenvironment parameters The cognition-based network security technologiesThe rapid merging and processing technologies of the (4) The cognition-based link efficiently transferringglobal environmental information technologies The global network environment situation The link transferring technologies with the learning(including network security situation) generating and reasoning capabilitiestechnologies The link reconfiguring technologies(2) The User demands mapping and access control The cognitive radio based cross-layer routingtechnologies optimizing technologies The user demands mapping and forecast analyzing (5) The cognition-based network organizing andtechnologies information exchanging technologies The cognition-based user access controlling The network topology on-demand configuringtechnologies technologies(3) The policy-based network resource managing and The end-to-end connecting and QoS providingcontrolling technologies technologies The service level agreement (SLA) and network policy The network nodes and switching mode reconfiguring
technologies VI. CONCLUSION V. THE IDEAS AND SUGGESTIONS ON THE DEVELOPMENT For the application environment and user demands dynamically changed multi-domain complex networks, it is OF COGNITIVE COMMUNICATION NETWORKS needed to multi-angle sensing the network environment, user To propose a new communication network architecture demands, network resources usage, service supporting,and build a cognitive communication network with the security level, etc. Implementing a communication networkability of cognition and reconfiguration is no easy task, with cognitive ability can improve the learning and self-requiring long-term researching and investigating. The organizing capacity of the communication network,current implementations and relevant technology on dynamically configure and restructure the network, andcognitive network is in its progress, and has not been a broad better adapt to the complex and diverse changes ofconsensus. However, the direction and focus of the application environments and user demands.researches are already clear, and the key technologyresearches have begun. These technologies (such as REFERENCEcommunication network environment rapid detection, policy-  Teamwork and Collaboration in Cognitive Wireless Networks.Nolan,based communication network resource management and K.E.; Doyle, L.E.;Wireless Communications, IEEE Volume 14, Issuecontrol, the cognition-based and efficient link transmission, 4, August 2007 Page(s):22–27.the cognition-based networking and information exchanging  Utilization of Location Information in Cognitive Wirelesstechnology) reflect the important characteristics of cognitive Networks.Celebi, H.; Arslan, H.;Wireless Communications, IEEE Volume 14, Issue 4, August 2007 Page(s):6–13.communication networks, and are the important ideas for  Cognitive Wireless Networks.Mahonen, P.; Zorzi, M.;Wirelessimprovement and technological changes on the existing Communications, IEEE Volume 14, Issue 4, August 2007 Page(s):4-communication network architecture. First, break through the 5.key technologies in cognitive communication networks is  Guest Editorial -Adaptive, spectrum agile and cognitive wirelessneeded. Second, realize the heterogeneous converged networks.Cordeiro, C.; Daneshrad, B; Evans, J; Mandayam,networks with the local cognitive capability based on the N.;Marshall, P.;N, S.S.; Cimini, L.;Selected Areas inexisting network conditions. Finally, implement the wide- Communications, IEEE Journal on Volume 25, Issue 3, April 2007 Page(s):513–516.area cognitive communications network.  Towards Cognitive Telecommunication Networks. Safak, Mehmet; Signal Processing and Communications Applications, 2007. SIU 2007. IEEE 15th 11-13 June 2007 Page(s):1-4.