Femtocell operator entry decision with spectrum bargaining and service competition

This paper analyzes the effect of the entry of a femtocell operator into a mobile communications market where a macrocell operator exists. The analysis is conducted using a game-theory-based model, specifically a threelevel multi leaderfollower game, where different solution concepts are applied: Shapley value, Nash equilibrium and Wardrop equilibrium. It aims to answer the question of which benefit mobile communication users get from the entry of a femtocell operator into the market. The equilibrium is assessed from the point of view of each agent (e.g. profits and utilities), and of the whole (e.g. social welfare). A case for regulatory intervention is made. © 1997-2012 IEEE.This work has been supported by the Spanish Ministry of Economy and Competitiveness through project TIN2010-21378-C02-02.Guijarro Coloma, LA.; Pla, V.; Vidal Catalá, JR.; Martínez Bauset, J. (2012). Femtocell operator entry decision with spectrum bargaining and service competition. IEEE Communications Letters. 16(12):1976-1979. https://doi.org/10.1109/LCOMM.2012.101712.121645S19761979161

Restriccion de Acceso Extendida para Manejar Despliegues Masivos de ¿ Comunicaciones Tipo Maquina (mMTC)

[ES] La comunicacion masiva tipo m ¿ aquina (mMTC) ha presentado un momento promete- ¿ dor para generar conexiones potentes y ubicuas que enfrentan muchos desaf¿¿os nuevos. Las redes celulares son la solucion potencial debido a su amplio despliegue de in- ¿ fraestructura, confiabilidad, seguridad y eficiencia. En las redes mMTC basadas en comunicacion celular, el canal de acceso aleatorio se utiliza para establecer la conexi ¿ on¿ entre los dispositivos MTC y las estaciones base (eNBs), donde el principal desaf¿¿o es la conectividad escalable y eficiente para una enorme cantidad de dispositivos. Para hacer frente a esto, el Third Generation Partnership Project (3GPP) ha sugerido la restriccion de acceso extendida (EAB) como un mecanismo para el control de la con- ¿ gestion. Las eNBs activan o desactivan EAB utilizando un coeficiente de congesti ¿ on. En ¿ este documento se presenta un enfoque para implementar el coeficiente de congestion¿ de modo que EAB pueda operar y as¿¿ manejar los episodios de congestion en escenarios ¿ de mMTC. Tambien se examina el rendimiento de EAB bajo diferentes cargas de tr ¿ afico ¿ de MTC y configuraciones de ciclo de paginacion en t ¿ erminos de indicadores clave de ¿ rendimiento de la red (KPIs). Los resultados numericos demuestran la efectividad del ¿ metodo propuesto para detectar episodios de congesti ¿ on. Adem ¿ as se demuestra que el ¿ aumento del valor de la configuracion del ciclo de paginaci ¿ on influye en el compor- ¿ tamiento de la red bajo EAB.[EN] Massive machine type communication (mMTC) has presented a promising moment to generate powerful and ubiquitous connections that face plenty of new challenges. Cellular networks are the potential solution owing to their extensive infrastructure deployment, reliability, security, and efficiency. In cellular-based mMTC networks, the random access channel is used to establish the connection between MTC devices and base stations (eNBs), where the scalable and efficient connectivity for a tremendous number of devices is the primary challenge. To deal with this, the Third Generation Partnership Project (3GPP) has suggested the extended access barring (EAB) as a mechanism for congestion control. The eNBs activate or deactivate EAB using a congestion coefficient. In this paper, an approach to implementing the congestion coefficient is presented so that EAB can operate thus handling congestion episodes in mMTC scenarios. Moreover, the performance of EAB is examined under different MTC traffic loads and paging cycle configurations concerning network key performance indicators (KPIs). Numerical results demonstrate the effectiveness of the proposed method to detect congestion episodes. Also, it is shown that increasing the value of the paging cycle configuration influence on the network behavior under EAB.This work was supported in part by the Ministry of Economy and Competitiveness of Spain under Grants TIN2013-47272-C2-1-R and TEC2015- 71932-REDT.Tello-Oquendo, L.; Vidal Catalá, JR.; Pla, V.; Martínez Bauset, J. (2018). Extended Access Barring for Handling Massive Machine Type Communication (mMTC) Deployments. NOVASINERGIA. 1(2):38-44. http://hdl.handle.net/10251/121752S38441

Performance Analysis and Optimal Access Class Barring Parameter Configuration in LTE-A Networks With Massive M2M Traffic

[EN] Over the coming years, it is expected that the number of machine-to-machine (M2M) devices that communicate through long term evolution advanced (LTE-A) networks will rise significantly for providing ubiquitous information and services. However, LTE-A was devised to handle human-to-human traffic, and its current design is not capable of handling massive M2M communications. Access class barring (ACB) is a congestion control scheme included in the LTE-A standard that aims to spread the accesses of user equipments (UEs) through time so that the signaling capabilities of the evolved Node B are not exceeded. Notwithstanding its relevance, the potential benefits of the implementation of ACB are rarely analyzed accurately. In this paper, we conduct a thorough performance analysis of the LTE-A random access channel and ACB as defined in the 3GPP specifications. Specifically, we seek to enhance the performance of LTE-A in massive M2M scenarios by modifying certain configuration parameters and by the implementation of ACB. We observed that ACB is appropriate for handling sporadic periods of congestion. Concretely, our results reflect that the access success probability of M2M UEs in the most extreme test scenario suggested by the 3GPP improves from approximately 30%, without any congestion control scheme, to 100% by implementing ACB and setting its configuration parameters properly.This work was supported in part by the Ministry of Economy and Competitiveness of Spain under Grants TIN2013-47272-C2-1-R and TEC2015-71932-REDT. The work of L. Tello-Oquendo was supported in part by Programa de Ayudas de Investigacion y Desarrollo (PAID), Universitat Politecnica de Valencia. The work of I. Leyva-Mayorga was supported in part by Grant 383936 CONACYT-Gobierno del Estado de Mexico 2014.Tello-Oquendo, L.; Leyva-Mayorga, I.; Pla, V.; Martínez Bauset, J.; Vidal Catalá, JR.; Casares-Giner, V.; Guijarro, L. (2018). Performance Analysis and Optimal Access Class Barring Parameter Configuration in LTE-A Networks With Massive M2M Traffic. IEEE Transactions on Vehicular Technology. 67(4):3505-3520. https://doi.org/10.1109/TVT.2017.2776868S3505352067

Entry, competition and regulation in cognitive radio scenarios: a simple game theory model

[EN] Spectrum management based on private commons is argued to be a realistic scenario for cognitive radio deployment within the current mobile market structure. A scenario is proposed where a secondary entrant operator leases spectrum from a primary incumbent operator. The secondary operator innovates incorporating cognitive radio technology, and it competes in quality of service and price against the primary operator in order to provide service to users. We aim to assess which benefit users get from the entry of secondary operators in the market. A game theory-based model for analyzing both the competition between operators and the subscription decision by users is proposed. We conclude that an entrant operator adopting an innovative technology is better off entering the market, and that a regulatory authority should intervene first allowing the entrant operator to enter the market and then setting a maximum amount of spectrum leased. This regulatory intervention is justified in terms of users utility and social welfare.This work was supported by Spanish government through project TIN2010-21378-C02-02.Guijarro Coloma, LA.; Pla, V.; Vidal Catalá, JR.; Martínez Bauset, J. (2012). Entry, competition and regulation in cognitive radio scenarios: a simple game theory model. Mathematical Problems in Engineering. 1-13. https://doi.org/10.1155/2012/620972S11

A schizophrenia-like psychotic disorder secondary to an arachnoid cyst remitted with neurosurgical treatment of the cyst

We describe a case of delusional psychosis that was terminated by neurosurgical removal of a large arachnoid cyst. The patient was suffering his first psychotic episode and had symptoms typical of schizophrenia. The case underscores the importance of considering that an arachnoid cyst can induce psychopathological symptoms, even those of schizophrenia. Indeed, such symptoms may be the cyst's only clinical manifestation. In addition, the case highlights the importance of doing a structural imaging test when confronted with a first episode of psychosis, especially if the episode is relatively late in appearance. Such imaging may lead to a diagnosis that in turn can enable a definitive neurosurgical resolution of the psychosis

Validity of a self-reported diagnosis of depression among participants in a cohort study using the Structured Clinical Interview for DSM-IV (SCID-I).

Abstract Background: Depression assessment in population studies is usually based on depressive symptoms scales. However, the use of scales could lead to the choice of an arbitrary cut-off point depending on the sample characteristics and on the patient diagnosis. Thus, the use of a medical diagnosis of depression could be a more appropriate approach. Objective: To validate a self-reported physician diagnosis of depression using the Structured Clinical Interview for DSM-IV (SCID-I) as Gold Standard and to assess the factors associated to a valid self-reported diagnosis. Methods: The SUN Project is a cohort study based on university graduates followed-up through postal questionnaires. The response to the question included in the questionnaire: Have you ever been diagnosed of depression by a physician? was compared to that obtained through the SCID-I applied by a psychiatrist or a clinical psychologist. The percentages of confirmed depression and non-depression were assessed for the overall sample and according to several characteristics. Logistic regression models were fitted to ascertain the association between different factors and a correct classification regarding depression status. Results: The percentage of confirmed depression was 74.2%; 95% confidence interval (95% CI) =63.3-85.1. Out of 42 participants who did not report a depression diagnosis in the questionnaire, 34 were free of the disease (%confirmed non-depression=81.1%; 95% CI=69.1- 92.9). The probability of being a true positive was higher among ex- smokers and non-smokers and among those overweight or obese but the differences were not statistically significant. Conclusion: The validity of a self-reported diagnosis of depression in the SUN cohort is adequate. Thus, this question about depression diagnosis could be used in further investigations regarding this disease in this graduate cohort study

Dynamic Spectrum Sharing in Cognitive Radio Networks Using Truthful Mechanisms and Virtual Currency

In cognitive radio networks, there are scenarios where secondary users (SUs) utilize opportunistically the spectrum originally allocated to primary users (PUs). The spectrum resources available to SUs fluctuates over time due to PUs activity, SUs mobility and competition between SUs. In order to utilize these resources efficiently spectrum sharing techniques need to be implemented. In this paper we present an approach based on game-theoretical mechanism design for dynamic spectrum sharing. Each time a channel is not been used by any PU, it is allocated to SUs by a central spectrum manager based on the valuations of the channel reported by all SUs willing to use it. When an SU detects a free channel, it estimates its capacity according to local information and sends the valuation of it to the spectrum manager. The manager calculates a conflict-free allocation by implementing a truthful mechanism. The SUs have to pay for the allocation an amount which depends on the set of valuations. The objective is not to trade with the spectrum, but to share it according to certain criteria. For this, a virtual currency is defined and therefore monetary payments are not necessary. The spectrum manager records the credit of each SU and redistributes the payments to them after each spectrum allocation. The mechanism restricts the chances of each SU to be granted the channel depending on its credit availability. This credit restriction provides an incentive to SUs to behave as benefit maximizers. If the mechanism is truthful, their best strategy is to communicate the true valuation of the channel to the manager, what makes possible to implement the desired spectrum sharing criteria. We propose and evaluate an implementation of this idea by using two simple mechanisms which are proved to be truthful, and that are tractable and approximately efficient. We show the flexibility of these approach by illustrating how these mechanisms can be modified to achieve different sharing objectives which are trade-offs between efficiency and fairness. We also investigate how the credit restriction and redistribution affects the truthfulness of these mechanisms.This work was supported by the Spanish government through Projects TIN 2008-06739-C04-02 and TIN 2010-21378-C02-02.Vidal Catalá, JR.; Pla, V.; Guijarro Coloma, LA.; Martínez Bauset, J. (2013). Dynamic Spectrum Sharing in Cognitive Radio Networks Using Truthful Mechanisms and Virtual Currency. Ad Hoc Networks. 11:1858-1873. https://doi.org/10.1016/j.adhoc.2013.04.010S185818731

Flexible Dynamic Spectrum Allocation in Cognitive Radio Networks Based on Game-Theoretical Mechanism Design

Part 4: Resource Allocation RadioInternational audienceIn this paper we present an approach based on game-theoretical mechanism design for dynamic spectrum allocation in cognitive radio networks. Secondary users (SU) detect when channels can be used without disrupting any primary user and try to use them opportunistically. When an SU detects a free channel, it estimates its capacity and sends the valuation of it to a central manager. The manager calculates a conflict-free allocation by implementing a truthful mechanism. The SUs have to pay for the allocation an amount which depends on the set of valuations, and they behave as benefit maximizers. We present and test two mechanisms implementing this idea which are proved to be truthful, and that are tractable and approximately efficient. We show the flexibility of these mechanisms by illustrating how they can be modified to achieve other objectives such as fairness and also how they can operate without really charging the SUs