With the tremendous growth in wireless technology the increasing demand for spectrum resources is causing spectrum scarcity. Several surveys show that most of the time and at most of the places licensed bands are underutilized. Cognitive radio (CR) is a promising technology which has the ability to deal with the increasing demand of spectrum bands as it adapts itself according to the surroundin...

Cognitive radio (CR) paradigm was introduced, towards addressing challenges, related with radio spectrum scarcity and increased needs for wireless networking services provision. In this direction, CR networks exploit novel networking architectures, as well as dynamic radio spectrum access techniques and methods, alleviating problems, regarding limited wireless networking resources and their ine...

Cognitive radios (CR) are intelligent radio devices that can sense the radio environment and adapt to changes in the radio environment. Spectrum sensing and spectrum access are the two key CR functions. In this paper, we present a spectrum sensing error aware MAC protocol for a CR network collocated with multiple primary networks. We explicitly consider both types of sensing errors in the CR MA...

Recent advances in cognitive radio technology have drawn immense attention to higher layer protocols above medium access control, such as transmission control protocol (TCP). Most proposals to improve the TCP performance in cognitive radio (CR) networks have assumed that either all nodes are in CR networks or the TCP sender side is in CR links. In those proposals, lower layer information such a...

A study by Cisco indicates a drastic increase in mobile data and that almost 66% of the mobile data was videorelated by 2015 [1]. Such dramatic increase in wireless video traffic, coupled with the depleting spectrum resource, poses great challenges to today’s wireless networks. It is of great importance to improve the wireless network capacity by promoting more efficient use of spectrum, which ...

—Cognitive Radio (CR) is a novel technology that promises to solve the lack of spectrum by allowing secondary users to use licensed band, so that they can coexist with primary users without causing interference to their communications. With the development of CR, extending to the level of network, cognitive radio networks (CRNs) emerge as the times require. Nowadays the operational aspects of ...

Cognitive radio (CR) is a technology exploiting knowledge from very diverse fields, such as machine learning, information theory, and wireless communications. The first part of the report introduces state-of-the-art survey on CR. It begins with survey on software defined radio (SDR), since it is the key enabling technology for future development of practical cognitive systems. Because the work ...

Transmission Control Protocol (TCP) is the most important transport layer protocol being used nowadays. It suffers from many problems over mobile networks especially over Cognitive Radio (CR). CR is one of the latest mobile technologies that brings its own share of problems for TCP. The buffer overflow for CR secondary network relay node can affect the performance of TCP. The contribution of th...

This paper investigates the performance of optimum combining (OC) in underlay cognitive radio (CR) in the presence of multiple primary user’s transmitters (PUTxs) in flat Rayleigh fading channels. The number of PUTxs Lt and antennas at secondary user receiver (SU-Rx) Kr are related as Lt ≥ Kr. Closed form expressions are obtained for the ergodic capacity and average bit error rate (BER) of the ...

The cognitive radio (CR) concept is promising to relax the pressure on the available radio resources and increase the efficiency of their use by dynamic spectrum allocation and spectrum sharing. Research focus related to CR networks is recently moving from simulation-based investigations to actual testbeds, many of them based on Wireless Sensor Networks (WSN), which support some CR research sce...