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Yaacoub E.,Qatar Mobility Innovations Center
2015 IEEE Wireless Communications and Networking Conference, WCNC 2015 | Year: 2015

Joint channel sensing and resource allocation in femtocell networks is investigated. An approach consisting of using jointly a sensing module in addition to a normal femto module performing resource allocation simultaneously with channel sensing is proposed. The sensed interference levels are used to define an interference transformation function that prioritizes the allocation of subcarriers based on the level of interference they are subjected to. Then, a resource allocation algorithm based on using interference transformation functions is presented. By incorporating interference information in a transformed channel gain, it permits the allocation of subcarriers subjected to little or no interference with high priority, and unfavors the allocation of the more interfered subcarriers. Simulation results show significant performance improvement when the proposed method is implemented. © 2015 IEEE. Source


Imran A.,University of Oklahoma | Imran M.A.,University of Surrey | Abu-Dayya A.,Qatar Mobility Innovations Center | Tafazolli R.,University of Surrey
IEEE Transactions on Wireless Communications | Year: 2014

Despite years of physical-layer research, the capacity enhancement potential of relays is limited by the additional spectrum required for Base Station (BS)-Relay Station (RS) links. This paper presents a novel distributed solution by exploiting a system level perspective instead. Building on a realistic system model with impromptu RS deployments, we develop an analytical framework for tilt optimization that can dynamically maximize spectral efficiency of both the BS-RS and BS-user links in an online manner. To obtain a distributed self-organizing solution, the large scale system-wide optimization problem is decomposed into local small scale subproblems by applying the design principles of self-organization in biological systems. The local subproblems are non-convex, but having a very small scale, can be solved via standard nonlinear optimization techniques such as sequential quadratic programming. The performance of the developed solution is evaluated through extensive simulations for an LTE-A type system and compared against a number of benchmarks including a centralized solution obtained via brute force, that also gives an upper bound to assess the optimality gap. Results show that the proposed solution can enhance average spectral efficiency by up to 50% compared to fixed tilting, with negligible signaling overheads. The key advantage of the proposed solution is its potential for autonomous and distributed implementation. © 2002-2012 IEEE. Source


Imran R.,University of Jordan | Odeh M.,University of Luxembourg | Zorba N.,Qatar Mobility Innovations Center | Verikoukis C.,Catalonia Technology Center of Telecomunications
IEEE Transactions on Wireless Communications | Year: 2013

Multiple Input Multiple Output (MIMO) adds a new dimension, the spatial one, to be optimized in Cognitive Radio (CR) by offering service simultaneously to more than one user. In this paper, statistical optimization techniques are applied to assess the performance of the Quality of Experience (QoE) in CR systems, where each user has different demands. A Multiuser scenario is considered where the transmitter can accomplish either a random or an opportunistic scheduling approach. Closed form expressions are derived for different scenarios and obtained for three QoE indicators in the system. The performance of primary and secondary users in such scenarios are mathematically formulated and compared their results to computer simulations. © 2002-2012 IEEE. Source


Alam M.M.,Qatar Mobility Innovations Center | Hamida E.B.,Qatar Mobility Innovations Center
Sensors (Switzerland) | Year: 2014

In this survey a new application paradigm life and safety for critical operations and missions using wearable Wireless Body Area Networks (WBANs) technology is introduced. This paradigm has a vast scope of applications, including disaster management, worker safety in harsh environments such as roadside and building workers, mobile health monitoring, ambient assisted living and many more. It is often the case that during the critical operations and the target conditions, the existing infrastructure is either absent, damaged or overcrowded. In this context, it is envisioned that WBANs will enable the quick deployment of ad-hoc/on-the-fly communication networks to help save many lives and ensuring people's safety. However, to understand the applications more deeply and their specific characteristics and requirements, this survey presents a comprehensive study on the applications scenarios, their context and specific requirements. It explores details of the key enabling standards, existing state-of-the-art research studies, and projects to understand their limitations before realizing aforementioned applications. Application-specific challenges and issues are discussed comprehensively from various perspectives and future research and development directions are highlighted as an inspiration for new innovative solutions. To conclude, this survey opens up a good opportunity for companies and research centers to investigate old but still new problems, in the realm of wearable technologies, which are increasingly evolving and getting more and more attention recently. © 2014 by the authors; licensee MDPI, Basel, Switzerland. Source


Hameed Mir Z.,Qatar Mobility Innovations Center | Filali F.,Qatar Mobility Innovations Center
Eurasip Journal on Wireless Communications and Networking | Year: 2014

Various wireless communication systems exist, which enable a wide range of applications and use cases in the vehicular environment. These applications can be grouped into three types, namely, road safety, traffic efficiency, and infotainment, each with its own set of functional and performance requirements. In pursuance of assisting drivers to travel safely and comfortably, several of these requirements have to be met simultaneously. While the coexistence of multiple radio access technologies brings immense opportunities towards meeting most of the vehicular networking application requirements, it is equally important and challenging to identify the strength and weaknesses of each technology and understand which technology is more suitable for the given networking scenario. In this paper, we evaluate two of the most viable communication standards, Institute of Electrical and Electronics Engineers (IEEE) 802.11p and long-term evolution (LTE) by 3rd Generation Partnership Project for vehicular networking. A detailed performance evaluation study of the standards is given for a variety of parameter settings such as beacon transmission frequency, vehicle density, and vehicle average speed. Both standards are compared in terms of delay, reliability, scalability, and mobility support in the context of various application requirements. Furthermore, through extensive simulation-based study, we validated the effectiveness of both standards to handle different application requirements and share insight for further research directions. The results indicate that IEEE 802.11p offers acceptable performance for sparse network topologies with limited mobility support. On the other hand, LTE meets most of the application requirements in terms of reliability, scalability, and mobility support; however, it is challenging to obtain stringent delay requirements in the presence of higher cellular network traffic load. © 2014, Hameed Mir and Filali; licensee Springer. Source

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