A Hierarchical Spectrum Access Scheme for TV White Space Coexistence in Hetergeneous Networks

Among current techniques for dynamic access to television (TV) white space (TVWS), geolocation database-based access provides a promising performance in protecting the TV-band incumbents from interference that cannot be efficiently achieved in other license-exempt models. However, in heterogeneous wireless networks, most portable devices do not have such access and may cause interference to TV incumbents. We propose a hierarchical model for spectrum sharing in TVWS that includes a wide range of fixed and portable devices. In the first tier, the TV broadcaster can lease the spectrum bands to local fixed users based on a soft license agreement. The fixed users are allowed to share access to this spectrum with some mobile users in their proximity in exchange for cooperative relaying. We consider a practical scenario, where only partial channel state information (CSI) is available at the users\u27 transmitters, and we propose a robust algorithm against such uncertainties in CSI values. We also propose a reputation-based relay selection mechanism to identify selfish portable users. The proposed spectrum sharing framework can provide a practical model for TVWS-coexistence that prevents undesired interference to the incumbents while restricting interference among the unlicensed devices. The simulation results show the enhancement of fixed users\u27 rate compared with alternative relay selection methods

SMART: Coordinated Double-Sided Seal Bid Multiunit First Price Auction Mechanism for Cloud-Based TVWS Secondary Spectrum Market

Spectrum trading is an important aspect of television white space (TVWS) and it is driven by the failure of spectrum sensing techniques. In spectrum trading, the primary users lease their unoccupied spectrum to the secondary users for a market fee. Although spectrum trading is considered as a reliable approach, it is confronted with a spectrum transaction completion time problem, which negatively impacts on end-users Quality of Service and Quality of Experience metrics. Spectrum transaction completion time is the duration to successfully conduct TVWS spectrum trading. To address this issue, this paper proposes simple mechanism auction reward truthful (SMART), a fast and iterative machine learning-assisted spectrum trading model to address this issue. Simulated results indicate thatSMART out-performs referenced VERUM algorithm in three key performance indicators: bit-error rate, instantaneous throughput, and probability of dropped packets by 10%, 5%, and 15%, respectively

A Trust-Based Relay Selection Approach to the Multi-Hop Network Formation Problem in Cognitive Radio Networks

One of the major challenges for today’s wireless communications is to meet the growing demand for supporting an increasing diversity of wireless applications with limited spectrum resource. In cooperative communications and networking, users share resources and collaborate in a distributed approach, similar to entities of active social groups in self organizational communities. Users’ information may be shared by the user and also by the cooperative users, in distributed transmission. Cooperative communications and networking is a fairly new communication paradigm that promises significant capacity and multiplexing gain increase in wireless networks. This research will provide a cooperative relay selection framework that exploits the similarity of cognitive radio networks to social networks. It offers a multi-hop, reputation-based power control game for routing. In this dissertation, a social network model provides a humanistic approach to predicting relay selection and network analysis in cognitive radio networks

Theoretical-practical study of automated radioelectric spectrum trading mechanisms

[SPA]El incremento de la demanda de comunicaciones inalámbricas frente a un estático espectro radioeléctrico con el que hacerle frente ha terminado con éste casi asignado por completo, que no ocupado: la solución pasa por utilizarlo de forma más eficiente y uno de los mecanismos planteados es el comercio automático de espectro: hacer posible que los operadores con licencia alquilen porciones a otros para satisfacer demandas de usuarios en tiempo real en un mercado secundario, que permitiría un uso mayor y más dinámico del espectro al tiempo que mantiene los incentivos de los operadores que ya poseen licencia. La casuística de este área se debe al hecho de ser una problemática reciente, así como lo es la herramienta más hábitual para su resolución, Teoría de Juegos; y al número de modelos económicos de comercio pre-existentes con que se puede estudiar, que además no pueden aplicarse directamente por las peculiaridades del bien con que se comercia así como de los agentes. Este trabajo busca exponer una visión general, ordenada y didáctica de las líneas de investigación existentes en este concepto. Se muestra como los distintos trabajos desglosan el comercio de espectro en diferentes subbproblemas y sus combinaciones, con aplicaciones reales todavía lejanas y cómo la Teoría de Juegos es la solución que se adapta de forma más natural al sentido del mismo. [ENG] The increasing demand of wireless communications versus an static radio-electric spectrum to cope with it has led to an almost fully assigned but sparsely used spectrum. This work studies one of the mechanisms proposed to improve spectrum efficiency, automated spectrum trading: licensed operators would be able to lease unused bandwidth to unlicensed ones so as to satisfy real time demands from users in secondary markets, resulting in a higher and more dynamic usage of spectrum while having the advantage over any other resource allocation method that there is an incentive to those who got a license. The different case studies in the area exist due to the fact that it is a recent field of study and so it is the main tool used here: Game Theory; along with the number of economic models to study it, which can’t be directly applied because of the particular characteristics of the trading good and agents. We are looking to give a general, organized and didactic view of the diverse research lines on the area, showing how different works break spectrum trading up into what sub-problems and their combinations, still far from real applications, and how Game Theory is the most common and natural approach to deal with them.Escuela Técnica Superior de Ingeniería de TelecomunicaciónUniversidad Politécnica de Cartagen

An Agent-Based Model for Secondary Use of Radio Spectrum

Wireless communications rely on access to radio spectrum. With a continuing proliferation of wireless applications and services, the spectrum resource becomes scarce. The measurement studies of spectrum usage, however, reveal that spectrum is being used sporadically in many geographical areas and times. In an attempt to promote efficiency of spectrum usage, the Federal Communications Commission has supported the use of market mechanism to allocate and assign radio spectrum. We focus on the secondary use of spectrum defined as a temporary access of existing licensed spectrum by a user who does not own a spectrum license. The secondary use of spectrum raises numerous technical, institutional, economic, and strategic issues that merit investigation. Central to the issues are the effects of transaction costs associated with the use of market mechanism and the uncertainties due to potential interference.The research objective is to identify the pre-conditions as to when and why the secondary use would emerge and in what form. We use transaction cost economics as the theoretical framework in this study. We propose a novel use of agent-based computational economics to model the development of the secondary use of spectrum. The agent-based model allows an integration of economic and technical considerations to the study of pre-conditions to the secondary use concept. The agent-based approach aims to observe the aggregate outcomes as a result of interactions among agents and understand the process that leads to the secondary use, which can then be used to create policy instruments in order to obtain the favorable outcomes of the spectrum management

Application of non-orthogonal multiple access in cooperative spectrum-sharing networks over Nakagami-m fading channels

This paper proposes a novel non-orthogonal multiple access (NOMA)-based cooperative transmission scheme for a spectrum-sharing cognitive radio network, whereby a secondary transmitter (ST) serves as a relay and helps transmit the primary and secondary messages simultaneously with employing NOMA signaling. This cooperation is particularly useful when the ST has good channel conditions to a primary receiver but lacks of the radio spectrum. To evaluate the performance of the proposed scheme, the outage probability and system throughput for the primary and secondary networks are derived in closed forms. Simulation results demonstrate the superior performance gains for both networks thanks to the use of the proposed NOMAbased cooperative transmission scheme. It is also revealed that NOMA outperforms conventional orthogonal multiple access and achieves better spectrum utilization