Qatar Mobility Innovations Center

Doha, Qatar

Qatar Mobility Innovations Center

Doha, Qatar
Time filter
Source Type

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.

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.

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.

Ghazzai H.,King Abdullah University of Science and Technology | Yaacoub E.,Qatar Mobility Innovations Center | Alouini M.-S.,King Abdullah University of Science and Technology | Abu-Dayya A.,Qatar Mobility Innovations Center
IEEE Transactions on Vehicular Technology | Year: 2014

Energy efficiency aspects in cellular networks can contribute significantly to reducing worldwide greenhouse gas emissions. The base station (BS) sleeping strategy has become a well-known technique to achieve energy savings by switching off redundant BSs mainly for lightly loaded networks. Moreover, introducing renewable energy as an alternative power source has become a real challenge among network operators. In this paper, we formulate an optimization problem that aims to maximize the profit of Long-Term Evolution (LTE) cellular operators and to simultaneously minimize the CO2 emissions in green wireless cellular networks without affecting the desired quality of service (QoS). The BS sleeping strategy lends itself to an interesting implementation using several heuristic approaches, such as the genetic (GA) and particle swarm optimization (PSO) algorithms. In this paper, we propose GA-based and PSO-based methods that reduce the energy consumption of BSs by not only shutting down underutilized BSs but by optimizing the amounts of energy procured from different retailers (renewable energy and electricity retailers), as well. A comparison with another previously proposed algorithm is also carried out to evaluate the performance and the computational complexity of the employed methods. © 2014 IEEE.

Yaacoub E.,Qatar Mobility Innovations Center | Filali F.,Qatar Mobility Innovations Center | Abu-Dayya A.,Qatar Mobility Innovations Center
IEEE Journal on Selected Topics in Signal Processing | Year: 2015

Real-time streaming of scalable video coded (SVC) videos in vehicular networks is investigated, and novel cooperative vehicle-to-vehicle (V2V) communication methods are proposed. The proposed techniques are based on grouping the moving vehicles into cooperative clusters. Within each cluster, the long term evolution (LTE) system is used to send the data over long range cellular links to a selected cluster head, which multicasts the received video over IEEE 802.11p to vehicles in its cluster. Error concealment techniques are used to compensate the loss of frames that are not delivered on time for real-time video streaming. In addition, resource allocation to select the best subcarriers for LTE transmission is performed in order to enhance the received video quality. Moreover, metrics related to both quality of service (QoS) and quality of experience (QoE) are studied and analyzed for various video sequences of different characteristics. The V2V video streaming techniques are extended to the case of vehicle-to-infrastructure (V2I) communications. Simulation results show that the proposed methods lead to enhanced QoS and QoE compared to the non collaborative scenarios, and their performance tradeoffs compared to recent methods from the literature are discussed. © 2014 IEEE.

Kadri A.,Qatar Mobility Innovations Center
20th European Wireless Conference, EW 2014 | Year: 2014

In this paper, performance of suboptimal receivers for detection of weak M-ary chirp spread spectrum (MCSS) signals in non-Gaussian noise is considered. It is known that optimal receivers for detection weak signals in non-Gaussian consists of zero-memory nonlinearity (ZMNL) followed by the Gaussian correlator receiver. In order to implement the ZMNL, precise a priori knowledge of the first order probability density of the noise is required. However, in practice, it is difficult to know a priori the density of noise precisely. Therefore, it is important to study how an optimal receiver designed for an assumed or estimated noise density will perform when the actual noise density differs from that of the assumed one. In addition, it is useful to consider receivers with various nonlinearities, such as hard limiter, clipper, and hole puncher, that are easy to implement. In this paper, receivers with these suboptimal nonlinearities are analyzed and their symbol error rate (SER) estimates are obtained. The results are shown using the widely used e-mixture noise model. © VDE VERLAG GMBH, Berlin, Offenbach, Germany.

Yaacoub E.,Qatar Mobility Innovations Center
International Conference on Wireless and Mobile Computing, Networking and Communications | Year: 2014

This paper describes a method for BS on/off switching in LTE-Advanced (LTE-A). The proposed method uses information exchanged between base stations (BSs) on the X2 interface in order to determine the BSs that should be switched on or off. It does not require centralized intelligence controlling the on/off switching in the network. Instead, it relies on always active coverage BSs that control the on/off switching of capacity BSs within their coverage area. Hence, it can be implemented locally in a distributed way. Simulation results show that the proposed switch off method can lead to significant energy savings in the network. © 2014 IEEE.

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.

Yaacoub E.,Qatar Mobility Innovations Center | Abu-Dayya A.,Qatar Mobility Innovations Center
Computer Networks | Year: 2014

Real-time transmission of smart meter measurement data is investigated. A contention based approach exploiting the unused cellular spectrum, e.g. of 4G Long Term Evolution (LTE), is proposed. The proposed approach uses subsets of LTE resource blocks (RBs) as allocation units. It is based on channel aware reservation slotted Aloha over orthogonal frequency division multiple access (OFDMA) using time/frequency slots, which leads to a reduction of collision probability, prevents collisions in the transmission phase, and allows detecting these collisions at the reservation phase. The proposed method relies on an access point (AP) that indicates the "available" OFDMA subcarriers to the contending devices after receiving this information through coordination with the cellular base station (BS): The BS informs the AP of the LTE RBs that it intends to keep free for a certain time period (e.g., because the current load on the network does not mandate their allocation to primary cellular users). Then, with the proposed approach, the AP transmits pilot signals on the free channels so that they can be used by the contending devices. Simulation results show that a large number of smart meters can be successfully accommodated within a limited coverage area with the proposed approach, while transmitting their measurement data in real-time. © 2013 Elsevier B.V. All rights reserved.

Yaacoub E.,Qatar Mobility Innovations Center | Kubbar O.,Qatar Mobility Innovations Center
2012 IEEE Globecom Workshops, GC Wkshps 2012 | Year: 2012

Device-to-Device communications are studied in the framework of LTE public safety networks. We propose a model where devices cooperate on the short range by forming coalitions for the purpose of energy efficiency. In each coalition, a device is selected to communicate with the base station on the long range. Coalition formation is investigated both for the uplink and downlink directions. Simulation results show that significant energy savings can be achieved with the proposed approach compared to the non-collaborative case, in addition to reduced delay and enhanced quality-of-service (QoS). © 2012 IEEE.

Loading Qatar Mobility Innovations Center collaborators
Loading Qatar Mobility Innovations Center collaborators