Radio Frequency Spectrum

Spectrum management is an extremely important part of telecommunications policy and regulation. The allocation of spectrum for particular uses, and development of specific technical and service rules governing those allocations, are crucial determinants of telecommunications industry structure and performance. Not only does the management of the resource have an enormous impact on a nation's economic and social well-being, it is also of critical importance to the safety of life and property, and to national defense. Fast-growing demand, coupled with rapid technological change, have put increased pressure on the traditional, centralised, often bureaucratic, "command-and-control" methods of managing the resource. One alternative to the traditional, centralised method is moving spectrum management in the direction of a marketoriented solution, wherein property-like rights in the resource are traded on a decentralised basis, more like other resources. Another method for reducing the rigidities in the current system is for policy-makers to move spectrum management in the direction of a "spectrum commons" solution. Under this alternative, anyone can gain access to a particular block of spectrum or set of channels, subject only to certain basic rules. Recently, there has been increased interest in the spectrum commons approach, because of the success of unlicensed spectrum in providing consumer benefits and increased opportunities for entrepreneurial activity. This paper explores the spectrum commons approach and concludes that, even in the face of significant challenges, the potential benefits are significant enough to warrant serious consideration by telecommunications policy-makers in their role as spectrum managers. This conclusion applies not only to developed countries but also to developing countries, where the more decentralised, less bureaucratic approach could empower individuals and communities to expand networks, applications and services on their own initiative.

Spectrum Sensing is the main part in the Cognitive Radio system. In fact many researches have been realized the last decade, and several techniques have been proposed to perform the Spectrum Sensing. This manuscript deals with this subject by presenting the most used techniques, by categorizing them as Cooperative and Blind, according to their requirements.

IEEE 802.11 and Bluetooth, these two operating in the unlicensed 2.4Ghz frequency band are becoming more and more popular in the mobile computing world. The number of devices equipped with IEEE 802.11 and Bluetooth is growing drastically. Result is the number of co-located devices , say within 10meters, grown to a limit, so that it may cause interference issues in the 2.4Ghz radio frequency spectrum. Bluetooth supports both voice(SCO) and data(ACL) packets. In this paper we investigate these interference issues and use a new Bluetooth voice packet named synchronous connection-oriented with Repeated Transmission (SCORT) to study the improvement in performance. For the sake of simulation results, we provide a comprehensive simulation results using MATLAB Simulink.

IEEE 802.11 and Bluetooth, these two operating in the unlicensed 2.4Ghz frequency band are becoming more and more popular in the mobile computing world. The number of devices equipped with IEEE 802.11 and Bluetooth is growing drastically. Result is the number of co-located devices , say within 10meters, grown to a limit, so that it may cause interference issues in the 2.4Ghz radio frequency spectrum. Bluetooth supports both voice(SCO) and data(ACL) packets. In this paper we investigate these interference issues and use a new Bluetooth voice packet named synchronous connection-oriented with Repeated Transmission (SCORT) to study the improvement in performance. For the sake of simulation results, we provide a comprehensive simulation results using MATLAB Simulink.

The radio frequency spectrum is getting more congested day by day due to the growth of wireless devices, applications, and the arrival of fifth generation (5G) mobile communications. This happens because the radio spectrum is a natural resource that has a restricted existence. Access to all devices can be granted, but in a more efficient way. To resolve the issue, cognitive radio technology has come out as a way, because it is possible to sense the radio spectrum in the neighboring. Spectrum sensing has been recognized as an important technology, in cognitive radio networks, to allow secondary users (SUs) to detect spectrum holes and opportunistically access primary licensed spectrum band without harmful interference. This paper considers the Energy Detection (ED) and Matched Filter Detection (MFD) spectrum sensing techniques as the baseline for a study where the so-called Hybrid Matched Filter Detection (Hybrid MFD) was proposed. Apart from an analytical approach, Monte Carlo simulations have been performed in MATLAB. These simulations aimed at understanding how the variation of parameters like the probability of false alarm, the signal-to-noise ratio (SNR) and the number of samples, can affect the probability of miss-detection. Simulation results show that i) higher probability of miss-detection is achieved for the ED spectrum sensing technique when compared to the MFD and Hybrid MFD techniques; ii) More importantly, the proposed Hybrid MFD technique outperforms MFD in terms of the ability to detect the presence of a primary user in licensed spectrum, for a probability of false alarm slightly lower than 0.5, low number of samples and low signal-to-noise ratio.

The radio frequency spectrum is getting more congested day by day due to the growth of wireless devices, applications, and the arrival of fifth generation (5G) mobile communications. This happens because the radio spectrum is a natural resource that has a restricted existence. Access to all devices can be granted, but in a more efficient way. To resolve the issue, cognitive radio technology has come out as a way, because it is possible to sense the radio spectrum in the neighboring. Spectrum sensing has been recognized as an important technology, in cognitive radio networks, to allow secondary users (SUs) to detect spectrum holes and opportunistically access primary licensed spectrum band without harmful interference. This paper considers the Energy Detection (ED) and Matched Filter Detection (MFD) spectrum sensing techniques as the baseline for a study where the so-called Hybrid Matched Filter Detection (Hybrid MFD) was proposed. Apart from an analytical approach, Monte Carlo simulations have been performed in MATLAB. These simulations aimed at understanding how the variation of parameters like the probability of false alarm, the signal-to-noise ratio (SNR) and the number of samples, can affect the probability of miss-detection. Simulation results show that i) higher probability of miss-detection is achieved for the ED spectrum sensing technique when compared to the MFD and Hybrid MFD techniques; ii) More importantly, the proposed Hybrid MFD technique outperforms MFD in terms of the ability to detect the presence of a primary user in licensed spectrum, for a probability of false alarm slightly lower than 0.5, low number of samples and low signal-to-noise ratio.