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Al-Kanj L.,American University of Beirut | Dawy Z.,American University of Beirut | Yaacoub E.,Wireless Innovations Center
IEEE Communications Surveys and Tutorials | Year: 2013

This paper presents a comprehensive overview on the area of energy-aware common content distribution over wireless networks with mobile-to-mobile cooperation. It is assumed that a number of mobile terminals (MTs) that are geographically close to each other are interested in downloading the same content from a server via a base station using a long-range wireless technology. Selected MTs download the content directly from the base station and transmit it to other MTs using a short-range wireless technology. This cooperation can lead to significant performance gains since short-range wireless technologies are energy efficient and provide higher data rates due to the geographical proximity among the MTs. In this paper, we highlight the main alternatives that shape the design of cooperative content distribution architectures with focus on energy efficiency. These include content segmentation, long-range and short-range distribution strategies, grouping of the MTs into cooperating clusters, single hop and multihop communications among the MTs, resource allocation, fairness considerations, and network dynamics. We also discuss various methods commonly utilized for developing content distribution algorithms and evaluating network performance. Finally, we present sample results for selected network scenarios, discuss related standardization activities, and highlight future research directions. © 1998-2012 IEEE.


Khabazian M.,Wireless Innovations Center | Mehmet-Ali M.,Concordia University at Montréal | Aissa S.,University of Quebec at Montréal
IEEE Systems Journal | Year: 2013

In this paper, we study the steady-state statistical properties of continuous communication path availability in vehicular ad hoc networks. We assume a network of highways with arbitrary topology. The mobile nodes arrive at the network through one of the traffic entry points following a Poisson process and move along a path according to a mobility model with a state-dependent mean speed. First, the joint distribution of the number of nodes in the highway segments of the network is determined. Then, the number of clusters in the node population of a network path is modeled as a Markovian birth-death process where a cluster is defined as a group of nodes that may communicate with each other directly or indirectly. Thus, the probability distributions of the number of clusters in a path and duration of continuous communication path availability time are derived as functions of mobility and traffic arrival parameters. We present mean durations of continuous availability and unavailability times and mean packet delay for end-to-end communications in a path. The given numerical results illustrate the effects of mobility and traffic arrival process on continuous communication path availability and packet delay. The results show that the mean durations of path availability and mean packet delay increase with the increasing transmission range. Clearly, while high path availability duration is desired but not high packet delay. Thus, the transmission range should not be chosen higher than needed for acceptable communication path availability, so as to maintain an acceptable mean packet delay. In practice, an adaptive transmission range may be required to achieve the right balance between the communication path availability and delay. The analytical results have also been compared with some available experimental studies and verified by two different simulation approaches. © 2007-2012 IEEE.


Yaacoub E.,Wireless Innovations Center | Dawy Z.,American University of Beirut
IEEE Communications Surveys and Tutorials | Year: 2012

OFDMA has been selected as the multiple access scheme for state-of-the-art wireless communication systems. Efficient resource allocation in OFDMA wireless networks is essential in order to meet the quality of service requirements of emerging services. In this paper, a survey of resource allocation and scheduling schemes in OFDMA wireless networks is presented. The focus is on the uplink direction. Resource allocation is surveyed in various scenarios: centralized and distributed, instantaneous and ergodic, optimal and suboptimal, single cell and multicell, cooperative and non-cooperative, in addition to different combinations of these variants. Directions for future research are outlined. © 1998-2012 IEEE.


Yaacoub E.,Wireless Innovations Center | Dawy Z.,American University of Beirut
2011 IEEE Wireless Communications and Networking Conference, WCNC 2011 | Year: 2011

Cognitive radio networks are receiving a lot of research attention lately. Most user equipment in state-of-the-art wireless communication systems are equipped with two antennas. In this paper, we take advantage of the two transmit antennas in an underlay cognitive radio network scenario. Secondary users use the two transmit antennas in order to insert a null in the direction of the primary base station, thus protecting primary users from interference on their uplink transmissions. Primary users benefit from the antennas in order to perform beam steering in direction of the primary BS, thus enhancing their uplink SINR without being concerned of the presence of the secondary users. This has the additional possible benefit of directing most primary radiation away from the secondary BS, thus reducing the interference on uplink secondary transmissions. © 2011 IEEE.


Yaacoub E.,Wireless Innovations Center
2011 IEEE Wireless Communications and Networking Conference, WCNC 2011 | Year: 2011

Opportunistic beamforming is investigated in the context of multicell LTE uplink resource allocation. A scheduling algorithm based on beam and resource block (RB) allocation with opportunistic beamforming is presented. Beams are formed in a pseudorandom fashion thus allowing users to opportunistically benefit from the antenna gain and interference rejection capabilities. Results show that enhanced performance is obtained with opportunistic beamforming. © 2011 IEEE.


Hrizi F.,Eurecom | Filali F.,Wireless Innovations Center
IWCMC 2010 - Proceedings of the 6th International Wireless Communications and Mobile Computing Conference | Year: 2010

Vehicular communication systems are becoming one of the most emerging research areas. Many efforts have been made to provide new applications and communication protocols adapted to this new kind of networks. The performance evaluation of these proposals is a crucial step for their validation. Therefore, the need of a new open-source, realistic and integrated simulation environment for vehicular networks is a fundamental and extremely pervasive motivation behind this work. In this paper, we propose simITS, an open-source simulation platform, aiming at a realistic evaluation of protocols for large scale vehicular networks. SimITS aims to simulate properly both road traffic conditions and wireless communications characteristics and at the same time to ensure the real time exchange of simulation data between them. Additionally, a new communication protocol stack designed for vehicular communications has been implemented. Finally, we validate the platform by a basic simulation study. Copyright © 2010 ACM.


Kadri A.,Wireless Innovations Center
IWCMC 2012 - 8th International Wireless Communications and Mobile Computing Conference | Year: 2012

This paper addresses non-coherent detection and performance of weak M-ary chirp spread-spectrum (MCSS) signals in non-Gaussian impulsive noise. The structure of the locally optimum Bayes detector (LOBD) is derived and consists of a zero-memory nonlinearity (ZMNL), a function of first-order noise density, followed by the non-coherent Gaussian envelope detector for MCSS signals. The performance of this receiver has been evaluated and closed-form expressions for symbol error rate (SER) and bit error rate (BER) have been derived. It has been shown that the SER and BER performances are functions of the signal-to-noise ratio (SNR), the sample size per symbol interval, the input data size, and the modulation parameters of MCSS signals. A comparison between the coherent and non-coherent detection for weak MCSS signals is also given. © 2012 IEEE.


Yaacoub E.,Wireless Innovations Center
2012 19th International Conference on Telecommunications, ICT 2012 | Year: 2012

The application of green communications to LTE networks is analyzed. An approach to reassign mobile users to different LTE BSs is proposed. The objective is to achieve energy savings by switching off lightly loaded BSs without compromising the tolerable outage rate in the network. The proposed approach takes into account the uplink and downlink directions, intercell interference, and scheduling. The proposed method was studied via simulations under different quality-of-service requirements in the uplink and downlink. The results show that significant savings can be achieved by the proposed approach, without increasing the outage rate in the network. © 2012 IEEE.


Yaacoub E.,Wireless Innovations Center
2012 IEEE Online Conference on Green Communications, GreenCom 2012 | Year: 2012

Green communications in LTE networks with environmentally friendly small cell base stations (BSs) are investigated. An approach to reassign mobile users to different LTE BSs is proposed. The objective is to achieve energy savings by switching off macrocell BSs and offloading the traffic to small cell BSs having a lower operating cost, or powered by renewable energy sources, without compromising the tolerable outage rate in the network. The proposed approach takes into account the uplink and downlink directions, intercell interference, scheduling, and base station operating costs. The proposed method was studied via simulations under different quality-of-service requirements in the uplink and downlink. The results show that significant gains can be achieved by the proposed approach. © 2012 IEEE.


Msadaa I.C.,Eurecom | Cataldi P.,Eurecom | Filali F.,Wireless Innovations Center
Proceedings - NGMAST 2010: 4th International Conference on Next Generation Mobile Applications, Services, and Technologies | Year: 2010

Intelligent Transportation Systems (ITS) have been under development since the 80's as part of a global strategy for solving many of our modern life transportation problems. These systems enable people to reach their destinations in a safe, efficient, and comfortable way. In order to reach that goal, several radio access technologies (RAT) such as UMTS, WiFi, WiMAX and 5.9 GHz have been proposed for next generation ITS. Yet, the coexistence of these technologies in the vehicles raises the challenge of choosing the most appropriate RAT. In order to address this problem and define optimal rules for the communication technology selection, comparisons on the network performance have to be done. In this paper, we compare two of the most promising infrastructure-based wireless technologies: mobile WiMAX (based on IEEE 802.16e standard) and the 5.9 GHz technology based on the upcoming IEEE 802.11p standard. We investigate, through simulation, the potential and limitations of both technologies as a communication media for vehicle-to-infrastructure (V2I) communications. The performance of the two systems is evaluated for different vehicle speeds, traffic data rates, and network deployments. © 2010 IEEE.

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