Yassine Hadjadj-Aoul

Cellular-based machine-to-machine: overload control

One of the most important problems posed by cellular-based machine type communications is congestion. Congestion concerns all the parts of the network, both the radio and the core network impacting both the user data plane and the control plane. In this article, we address the problem of congestion in machine type communications. We propose a congestion-aware admission control solution that selectively rejects signaling messages from MTC devices at the radio access network following a probability that is set based on a proportional integrative derivative controller reflecting the congestion level of a relevant core network node. We evaluate the performance of our proposed solution using computer simulations. The obtained results are encouraging. In fact, we succeed in reducing the amount of signaling while maintaining a target utilization ratio of resources in the core network.

Adaptive Energy Optimization in Multimedia-Centric Wireless Devices: A Survey

Over the last couple of years, there has been an exponential increase in the number of applications accessible from various mobile handsets, including Facebook, Twitter, YouTube, etc. In particular, rich media service distribution among smart-phones and other handheld devices is becoming increasingly popular among users. In fact, the next generation wireless technologies have put significant emphasis on supporting distribution of rich media content and video-on-demand services. However, energy consumption in the handheld wireless devices is a major bottleneck that hinders the growth of mobile device based rich media services. The biggest problem today in the mobile world is that the mobile devices are battery driven and the battery technologies are not matching the required energy demand. This paper outlines the major energy-consuming components in handheld devices like smart-phones, PDAs and other multimedia-centric wireless devices. Further, this paper surveys different research works on how the energy consumption could be optimized and provides detailed discussions on the latest energy saving techniques in the major components of the mobile devices. In addition, the paper surveys other systemic energy optimization techniques so that the overall battery life of the device is increased. Major global research projects and their research focus are then surveyed. Finally, a brief summary is provided along with some open research problems and different possible future research directions.

Congestion control for machine type communications

One of the most important problems posed by cellular-based machine type communications is congestion. Congestion concerns both the radio access network and the mobile core network, impacting both the user data and the control planes. In this paper, we address the problem of congestion in machine type communications. We propose a congestion-aware admission control solution that selectively rejects signaling messages from MTC devices at the radio access network following a probability that is set based on a proportional integrative derivative controller reflecting the congestion level of a relevant core network node. We evaluate the performance of our proposed solution using computer simulations. The obtained results are encouraging. In fact, we succeed in reducing the amount of signaling, to reach a target utilization ratio of resources in the core network.

Challenges, opportunities, and solutions for converged satellite and terrestrial networks

The current trend in telecommunications services provisioning is shifting toward global ubiquitous networking and unified service architecture. Given the diversity of access technologies, this global ubiquitous networking cannot be possible without efficient interworking between the different access players. This leads to the necessity of defining, implementing, and deploying common services control architecture, able to support a wide variety of services for users in a variety of roles (consumer, producer, or manager of communication and media). This article defines some issues related to the interworking operation between the satellite and terrestrial domains. It suggests some solutions and discusses their potential.

Geographical location and load based gateway selection for optimal traffic offload in mobile networks

To cope with the rapid increase of data traffic in mobile networks, operators are looking for efficient solutions that ensure the scalability of their systems. Decentralization of the network is one of the key solutions. With such solution, small-scale core network nodes (gateways) are locally deployed to serve the local community of users, in a decentralized fashion. In this paper, we devise methods that enable User Equipments (UEs), both in idle and active mode and while being on the move, to always have optimal Packet Data Network (PDN) connections in such decentralized networks. The proposed methods are compared based on their impacts on current 3GPP standards and the benefits of the overall approach are evaluated through simulations. Encouraging results are obtained.

Efficient Solutions for Enhancing Data Traffic Management in 3GPP Networks

As mobile data traffic is continuously increasing and the average revenues per user are getting lower due to flat-rate changing, operators are in need of means to cope with higher-than-expected data volumes introducing minimal additional capital expenditures. This paper investigates network decentralization in conjunction with the selective IP traffic offload approaches to handle such increased data traffic. We first devise different approaches based on a per-destination-domain-name basis, which offer operators a fine-grained control to determine whether a new IP connection should be offloaded or accommodated via the core network. Two of our solutions are based on Network Address Translation (NAT) named simple-NATing and twice-NATing, whereas a third one employs simple tunneling, and a fourth adopts multiple Access Point Names. We also propose methods enabling user equipment (UE) devices, both in idle and active modes, and while being on the move, to always have efficient packet data network connections. A qualitative analysis and a simulation study compare the different approaches with respect to cost, complexity, service continuity, and network performance, demonstrating the significance of the proposed scheme for multimedia applications.

On improving the group paging method for machine-type-communications

Machine-type-Communication (MTC) is seen as a major service in next generation cellular mobile networks. However, the forecasted very large number of MTC devices may overload the RAN (Radio Access Network) part of the network, which may impact Non-MTC communications. Group paging is considered as one of the most efficient mechanisms proposed to alleviate the problem of the RAN overload. In this paper, we introduce a new solution to improve the performance of the current group paging method and overcome its disadvantages. The proposed solution is intended for MTC devices in the RRC CONNECTED OUT OF SYNC state, in which MTC devices have an RRC context without being synchronized with the network. Numerical results demonstrate that the proposed solution highly improves the performance of existing group paging mechanisms.

QoE-based energy conservation for VoIP over WLAN

Minimizing energy consumption is becoming more and more crucial in todays mobile terminals communications. Reducing its use pass necessarily by exploiting low power design techniques and by adopting novel energy-aware applications and protocols. The focus in this paper mainly concerns the Voice over IP over Wireless Local Area Network (VoWLAN) application, which is beyond doubt the most popular application in mobile terminals. The real-time nature of this application makes the conventional approaches inefficient, as they conserve energy by either: (i) switching the wireless device from the active mode to the sleep mode when no data is buffered for transmission or reception, which completely block the mobile terminal in the active mode (i.e. waste of energy), or (ii) forcing the switching to the sleep mode, which is clearly a detrimental behavior for such delay-constrained application. The idea of the proposed paper is to wisely determine the optimal schedule between the Sleep and Wakeup periods based on the application requirements. Hence, we propose in the following a quality of experience (QoE)-aware protocol, maximizing the sleep mode duration, for VoIP application. The performance of the proposed protocol is performed through computer simulation. The obtained results clearly demonstrate the superiority of the protocol in conserving energy while keeping the QoE at a desired level.

QoS 2 : a framework for integrating quality of security with quality of service

Different security measures have emerged to encounter various Internet security threats, ensuring a certain level of protection against them. However, this does not come without a price. Indeed, there is a general agreement that high security measures involve high amount of resources, ultimately impacting the perceived Quality of Service (QoS). The objective of this paper is to define a framework, dubbed QoS2, that provides means to find a tradeoff between security requirements and their QoS counterparts. The QoS2 framework is based on the multiattribute decision-making theory. The performance of the QoS2 framework is evaluated through computer simulations. A use-case considering worm e-mail detection is used in the performance evaluation. Copyright

A methodology for performance/energy consumption characterization and modeling of video decoding on heterogeneous SoC and its applications

To meet the increasing complexity of mobile multimedia applications, SoCs equipping modern mobile devices integrate powerful heterogeneous processing elements among which Digital Signal Processors (DSP) and General Purpose Processors (GPP) are the most common ones. Due to the ever-growing gap between battery lifetime and hardware/software complexity in addition to applications computing power needs, the energy saving issue becomes crucial in the design of such architectures. In this context, we propose in this paper an end-to-end study of video decoding on both GPP and DSP. The study was achieved thanks to a two steps methodology: (1) a comprehensive characterization and evaluation of the performance and the energy consumption of video decoding, (2) an accurate high level energy model is extracted based on the characterization step.The characterization of the video decoding is based on an experimental methodology and was achieved on an embedded platform containing a GPP and a DSP. This step highlighted the importance of considering the end-to-end decoding flow when evaluating the energy efficiency of video decoding application. The measurements obtained in this step were used to build a comprehensive analytical energy model for video decoding on both GPP and DSP. Thanks to a sub-model decomposition, the developed model estimates the energy consumption in terms of processor clock frequency and video bit-rate in addition to a set of constant coefficients which are related to the video complexity, the operating system and the considered hardware architecture. The obtained model gave very accurate results (R2=97%) for both GPP and DSP energy consumption. Finally, based on the results emerged from the modeling methodology, we show how one can build rapidly a video decoding energy model for a given target architecture without executing the full characterization steps described in this paper.