Multi-zones of cognitive to fibre networks.
ABSTRACT The Cognitive Radio Network (CRN) was developed to solve the problem of scares spectrum for the next generation networks. The Cognitive Radio over Fibre (CRoF) subnet uses fiber connections to avoid the interruption in CRN services due to spectrum unavailability. The contribution of this paper is to submit a scheme where the two networks CRN and CRoF coexist to form a new multi-zoned secondary network. At least one CRoF Base Station (BS) is placed in each zone as the wireless provider for the other CRN-BSs. CRoF-BSs control communication between different sectored zones. Certain criteria must be followed to form these zones according to the free available resources and the number of expected users. Opnet simulation results proved the multi-zoned network performance over known CRN applications in saving processing time and increasing the throughput. Major changes are presented to the management of the secondary networks to guarantee the continuity of the submitted services.
Conference Paper: Renovate Cognitive Networks under Spectrum Unavailability.[Show abstract] [Hide abstract]
ABSTRACT: Spectrum availability is a decisive factor for the continuity of Cognitive Network (CN) broadcast. Cognitive networks lease the spectrum temporarily whenever the primary users went off. Thus, localized wireless changes within CN cells rapidly affect the transmissions of the cognitive radios. This situation becomes more complicated for cognitive mesh networks when establishing a link over many cells. Therefore, link formation failure may cause complete disruption at certain sites of the network. A mathematical model is first introduced to study the delay impacts of the spectrum unavailability on the CN's which has been analyzed as the most severe cause for the CN failures. In this paper, a new subnet called Cognitive Radio over Fibre (CRoF) is proposed as an alternative for the wireless links between cognitive base stations every time there is no free spectrum to communicate. In this proposed solution, the CRoF subnet splits the CN into zones according to the number of expected users and free spectrum available. Then, CRoF base stations are placed at the edges of the structured zones to act as seniors for other cognitive cells. Consequently, a new management for secondary networks is achieved for local spectrum access. Initial Opnet simulations show 11% time savings during packet delivery for the CRoF designed scenarios in comparison with traditional CN's. The proposed CRoF subnet provides a permanent solution to restore service delivery for the CN's affected by wireless changes.Sixth Advanced International Conference on Telecommunications, AICT 2010, 9-15 May 2010, Barcelona, Spain; 01/2010
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ABSTRACT: We develop opportunistic scheduling policies for cognitive radio networks that maximize the throughput utility of the secondary (unlicensed) users subject to maximum collision constraints with the primary (licensed) users. We consider a cognitive network with static primary users and potentially mobile secondary users. We use the technique of Lyapunov Optimization to design an online flow control, scheduling and resource allocation algorithm that meets the desired objectives and provides explicit performance guarantees.INFOCOM 2008. 27th IEEE International Conference on Computer Communications, Joint Conference of the IEEE Computer and Communications Societies, 13-18 April 2008, Phoenix, AZ, USA; 04/2008
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ABSTRACT: Software radios are emerging as platforms for multiband multimode personal communications systems. Radio etiquette is the set of RF bands, air interfaces, protocols, and spatial and temporal patterns that moderate the use of the radio spectrum. Cognitive radio extends the software radio with radio-domain model-based reasoning about such etiquettes. Cognitive radio enhances the flexibility of personal services through a radio knowledge representation language. This language represents knowledge of radio etiquette, devices, software modules, propagation, networks, user needs, and application scenarios in a way that supports automated reasoning about the needs of the user. This empowers software radios to conduct expressive negotiations among peers about the use of radio spectrum across fluents of space, time, and user context. With RKRL, cognitive radio agents may actively manipulate the protocol stack to adapt known etiquettes to better satisfy the user's needs. This transforms radio nodes from blind executors of predefined protocols to radio-domain-aware intelligent agents that search out ways to deliver the services the user wants even if that user does not know how to obtain them. Software radio provides an ideal platform for the realization of cognitive radioIEEE Personal Communications 09/1999;