System Architecture Design

pSHIELDSystem Architecture DesignPUCR uses unlicensed frequency bands or alternatively, fairly used licensed ones. Its success led FCC toconsider open further bands for unlicensed use. IEEE 802.22 is a standard for CR air interface(PHY/MAC), belonging to WRAN communication protocols. It is developed for Cognitive Radiotechniques, to exploit geographically unused spectrum. Additionally, IEEE P1900 is a standard committeeand group focusing on the development of standards dealing with spectrum management.Having a brief view on the architectural schemes of SDR/CR, we can add to prerequisite blocks (apartfrom the radio front end and the computer system we saw in previous paragraph) a control unit, capableof making decisions following spectrum sensing and concerning methods of spectrum management.Variability of options appears in the computing unit selection:a) General purpose processorb) Application specific processors and integrated circuitsc) FPGAs for reconfigurable computingd) Embedded SystemsThe last category shows that Embedded Systems and SDR/CR architectures fit quite well and direct us topSHIELD Network Layer application techniques. Reversely, speed of ESs, together with low energyrequirements, rather small programming effort and the specific nature of tasks they perform makeSDR/CR schemes a suitable communication model. Also, due to the nature of ESs’ Operating Systems,SDR/CR devices can have, comfortably, quick reset and reconfigurability processing times, without thedemand of lengthy off-line periods. The cost of the combination SRD/CR with ESs could be veryreasonable, allowing us to seamlessly improve network performance in application domains. CognitiveRadio, for example, is an emerging radio approach in emergency communications, to face issues of vitalimportance, such as the usual network congestion during the peak of a crisis or difficulties inintercommunication between authorities resulting from heterogeneous communication protocols andsystems.In chapter 6, System Design, SPD Driven Transmission and Trusted Connectivity are examined further,as functions of pSHIELD Network Layer, provided by the appliance of SDR/CR architecture.3.4 Middleware Layer DefinitionsThe Middleware layer is seen, from a pSHIELD perspective, as a pure software-based layer playing a keyrole to interface the Node and Network layer to the Overlay layer. The Middleware layer is shown in thebelow figure highlighted in grey.PUD2.3.2Issue 5 Page 41 of 122