Multiband cognitive radio (CR) signaling allows CR networks to efficiently take advantage of the unused frequency bands. Joint spectrum sensing and power allocation in CR systems has been shown to provide higher opportunities for CR transmission. In this work, joint spectrum sensing and resource allocation (power and bandwidth) are performed in a multiband CR system. This is achieved by defining an optimization problem which is formulated with the aim of minimizing CR network outage probability. It is shown that minimizing the outage probability of CR network is equivalent to maximizing the CR network achievable data rate. Hence, the related optimization problem converts to maximizing the average opportunistic CR data rate under constraints on interference, power budget and total available bandwidth leading to a non-convex optimization problem. As the original formulated optimization problem is inherently non-convex, it is converted into a convex problem where the optimal solution is obtained using the Lagrange multipliers method and linear programming. For performance comparison, the classical method based on equal bandwidth allocation for each subchannel is considered. Several numerical results are provided to contrast the performance of the proposed method compared to the classical method, in terms of the average achievable CR data rate.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

PurposeThe current extensive business ecosystem, characterized by technological advances and development, impressive customers, and increasing social concerns, has exerted great pressure on business organizations. Among different business values for affording this pressure, organizational agility is a critical factor that should be carefully incorporated in business processes. The main purpose of the present study is to investigate the role of social networking technology, as a crucial collaborative tool, on organizational agility.Design/methodology/approachA model based on structural equations was designed in this regard. The constructs of this model are quality of service, varieties of services, costs and speed of service as independent variables and also agility management as a dependent variable. Based on the conceptual model, a questionnaire was prepared and distributed among the experts of social networking technology and agility management. Based on Cochran's formula the sample size was 384. The response rate was 100%. The main statistical measures such as Chi-square ratio to the degree of freedom, Non-soft Fitness Index (RMSEA), Goodness of Fit Index (GFI) and Modified fitness index (AGFI) were employed for analyzing the model.FindingsResults of obtained data indicated that a variety of services as the main factor of social networking technology has the most impact on the agility of a company. Then, the speed of service, service quality and costs were ranked respectively in second to fourth. Providing information technology (IT) service perceptions, promoting the service climate and thorough identification of IT requirements are the main critical success factors for maintaining a robust impact of social networking technology on organizational agility. Moreover, a well-designed enterprise structure alongside employing newly developed IT infrastructures such as cloud computing certainly improves the capabilities of organizations to improve their agility.Originality/valueAlthough the literature suggests a positive impact among IT or social networks on organizational agility, it is deficient in relation to considering the impact of social networking. Furthermore, a structural equation model (SEM) is used for assessing unobservable latent constructs and their related interrelationship.

No abstract