System Architecture Design

pSHIELDSystem Architecture DesignpSHIELD Architecture, SDR in cooperation with Cognitive Radio (CR), will be used to derive from SPDmodules the corresponding desired communication and security functionalities.3.3.3 Cognitive RadioPUCognitive Radio is a radio communication standard, able to change its transmission and receptionparameters, according to conclusions deduced from sensing the frequency spectrum. The objective is todetect the unused spectrum and utilize it to set up radio communication. CR scouts the environment andadapts to user needs, without neither involving the user in this procedure, nor interfering with the hostnetwork, while conforming to FCC rules. As its inspirator Joseph Mitola III described, the motive behindCR is to render users aware of available radio resources, in order to serve their communication needs,without obstructing these resources’ allocation and normal function of the whole network. CR is itself anetwork node performing (concisely) the following actions, in the procedure of setting successfully a radiocommunication:• Detection of free frequency spectrum• Creation of a channel to use this spectrum• Function without interfering with native devicesAnd more analytically, the main functions and methods of CRs could include:• Spectrum SensingTransmitter detection: CR detect signals from specific transmitters in specific spectrumCooperative detection: information from multiple CRs is used for detectionInterference based detection• Spectrum Management• Spectrum Mobility Spectrum Analysis Spectrum Decision Spectrum Pooling: allocation of resources between users Spectrum Leasing Spectrum Sharing: a stack of spectrum is given to users (similar to MAC channeladdressing) Negotiated Spectrum Use Opportunistic Spectrum Use Dynamic Spectrum Access A CR user exchanges its operation frequencyAlthough primary observations concern frequency spectrum usage, other factors can be inspected also,such as user behaviour, channel conditions, network state and link performance. Subsequently the CRmay decide to alter communication settings, from which the most usual are waveform, protocol, frequencyand power, to meet the required level of QoS.PUD2.3.2Issue 5 Page 40 of 122