Cognitive Radio Network (CRN) has to stall its packet transmission periodically to sense the spectrum for Primary User’s (PU’s) transmission. The limited and dynamically available spectrum and fixed periodic schedule of transmission interruption makes it harder to model the performance of a CRNs. Again, an open and dynamic spectrum access model brings forth a serious challenge of sustenance amo...

Cognitive radio is an enabling technology of dynamic spectrum access (DSA) networking. In DSA, unlicensed secondary users can coexist with primary licensed users and can share the radio spectrum opportunistically. Broadcasting is an important networking primitive that is useful for many CRN applications such as control information dissemination, warning notification, etc. Unfortunately, the spo...

Cognitive radio (CR) is widely recognized as a novel approach to improve the spectrum efficiency. However, there exists one problem needed to be resolved urgently, that is the two conflicting goals in CR network: one is to minimize the interference to primary (licensed) system; the other is to maximize the throughput of secondary (unlicensed) system. Meanwhile, the secondary user (SU) has to mo...

As the deployment of new wireless devices and applications is growing rapidly there is an increase in demand for wireless radio spectrum. Researchers show that more than 70% of available spectrum is not used efficiently. For efficient utilization of spectrum we need to know whether the spectrum is used by primary user or not which is called Spectrum Sensing. The concept Cognitive Radio is propo...

Cognitive radio transceiver can opportunistically access the underutilized spectrum resource of primary systems for new wireless services. With interweave cognitive implementation, the secondary transmission may be interrupted by the primary user’s transmission. To facilitate the packet delay analysis of such secondary transmission, we study the resulting extended delivery time that includes bo...

We investigate revenue maximization problems in auctions for dynamic spectrum access. We consider the frequency division and spread spectrum methods of dynamic spectrum sharing. In the frequency division method, a primary spectrum user allocates portions of spectrum to different secondary users. In the spread spectrum method, the primary user allocates transmission powers to each secondary user...

Policy-based dynamic spectrum access is one of the spectrum access models being considered by regulators and researchers for regulating the behavior of cognitive radios. This approach to spectrum access decouples the policyrelated components (i.e., policy management, provisioning, and reasoning) from the radio platform. In policy-based spectrum access, the policy reasoner plays a critical role—...

P. Picardo, G. Sciani “Multimedial Signal Transmission with Spread Spectrum Modulation for Transport Applications” The proposed system is a module for images transmission-reception based on the integration between source coding techniques, namely JPEG image coding, and channel coding techniques, namely Spread Spectrum Modulation. Such integration allows one to protect images information, throug...

Cognitive radios (CRs) have been proposed to improve spectrum utilization by enabling opportunistic and dynamic spectrum access for unlicensed users. To enable efficient CR communications, a reliable control channel (CC) for exchanging control information is needed. In this paper, a direct sequence spread spectrum (DSSS)-based underlay CC design for distributed coordination in CR networks (CRNs...

Due to the increased usage of wireless communications in personal, commercial, and governmental capacities, efficient spectrum utilization has become a prime topic of interest. The Federal Communications Commission (FCC) governs spectrum usage and allocates specific ranges to licensed users. However, some spectrum ranges are overcrowded, while some are under-utilized. The overcrowded spectrum r...