@inproceedings {Simula.simula.2654,
	title = {Analysis of SR ARQ Delays Using Data-Bundling Over Markov Channels},
	journal = {The Nineteenth IEEE Symposium on Computers and Commuications (IEEE ISCC)},
	year = {2014},
	month = {June},
	publisher = {IEEE},
	type = {Conference},
	abstract = {Data-bundling is a useful technique that decreases the delivery delay of packet streams when they are transmitted over noisy channels and are subject to retransmission-based error control. In this paper, we investigate the packet delay statistics for a fully reliable selective repeat automatic repeat request (SR ARQ) where a data-bundling mechanism is employed. In more detail, we discuss a model for data-bundling to analyze the SR ARQ mechanism over wireless channels based on Markov chains. We evaluate various channel error distributions and analyze the buffer occupancy to check if the data-bundling mechanism provides efficient results. We further analyze the queueing, delivery and overall delay statistics at link layer. We found that using data-bundling can improve the delay performance of the SR ARQ mechanism, especially when bursty channels with heavily correlated errors are considered. Thus, this technique can bring useful improvements for real-time services, multimedia, and other delay-sensitive applications over wireless networks.},
	keywords = {Conference},
	author = {Ahmed, Iffat and Badia, Leonardo and Petlund, Andreas and Griwodz, Carsten and Halvorsen, P{\r a}l},
	editor = {Sahni, Sartaj}
}
@inproceedings {Simula.simula.2374,
	title = {Analysis of Management Policies for Multicast Transmission of Scalable Video Content in Next Generation Networks},
	journal = {IEEE International Wireless Communications and Mobile Computing Conference (IWCMC)},
	year = {2013},
	month = {July},
	pages = {1206-1211},
	publisher = {IEEE},
	type = {Conference},
	abstract = {Users of video multicast groups are highly heteroge- neous in terms of individual channel conditions and requirements for video transmission. Thus, their experienced quality may vary, making it a challenging task for the network to optimally configure the resource management. In this paper, we consider mathematical model to represent layered video content delivery in a multicast group. We compare various network policies to choose the optimum number of transmit opportunities and we investigate the role of feedback, which, if present, dynamically tunes the resource management. We analyze the actual perceived quality of the users as well as how their satisfaction levels vary in the multicast session. Simulation results show that the presence of feedback generally enhances the overall users quality; however, this improvement is heavily related to the resource allocation policy of the operator.},
	isbn = {978-1-4673-2479-3},
	doi = {10.1109/IWCMC.2013.6583728},
	author = {Ahmed, Iffat and Badia, Leonardo},
	editor = {Saracco, Roberto}
}
@inproceedings {Simula.simula.2376,
	title = {Analysis of PHY/Application Cross-Layer Optimization for Scalable Video Transmission in Cellular Networks},
	journal = {IEEE International Symposium on a World of Wireless Mobile and Multimedia Networks (WoWMoM)},
	year = {2013},
	month = {June},
	pages = {1-3},
	publisher = {IEEE},
	type = {Conference},
	abstract = {We investigate the optimization of video transmis- sions over cellular networks by using the H.264 Scalable Video Coding (SVC) at the application layer and an Adaptive Modula- tion and Coding (AMC) scheme at the physical layer. We analyze how the cross-layer optimization (XLO) of these two techniques together performs compared to a sequential and independent selection of video packets and Modulation and Coding Schemes (MCS) with no cross-layer optimization (NXLO), in terms of goodput and packet delivery delay. We formulate an analytical model based on a Markov chain representing the wireless channel, where each state is associated to a different channel quality corresponding to a set of possible choices of video layer and MCS. Our numerical results show that XLO significantly outperforms NXLO for video transmissions, thereby pointing out the strong need for cross-layer solutions in video transmission.},
	keywords = {Conference},
	doi = {10.1109/WoWMoM.2013.6583415},
	author = {Ahmed, Iffat and Badia, Leonardo},
	editor = {IEEE Internatio {Mobile} and Multimedia Networks {WoWMoM}}
}
@inproceedings {Simula.simula.2646,
	title = {Design of a Unified Multimedia-Aware Framework for Resource Allocation in LTE Femtocells},
	journal = {Proceedings of the 9th ACM international symposium on Mobility management and wireless access},
	year = {2011},
	month = {November},
	pages = {159-162},
	publisher = {ACM},
	type = {Conference},
	abstract = {In future 4G communication networks, it is expected that most of the bandwidth will be used to serve multimedia applications. Thus, there is a need for scheduling mechanisms, which can manage various types of multimedia communication (interactive, conversation, video streaming, etc.) and provide adequate Quality of Experience according to the application needs. The most promising candidate for 4G systems, i.e., Long Term Evolution, also integrates femtocells as a cost-effective solution for pervasive communication. In such a scenario, the implementation of effective scheduling mechanisms becomes even more important. Finally, before implementing scheduling policies on real devices, validation through simulation studies is often employed. For all these reasons, we investigated the implementation of an adaptive scheduling mechanism for an LTE scenario with femtocells within the well known ns3 simulator. This paper describes the preliminary steps of this activity.},
	keywords = {Conference},
	doi = {10.1145/2069131.2069160},
	author = {Ahmed, Iffat and Badia, Leonardo and Baldo, Nicola and Miozzo, Marco},
	editor = {Rolim, Jose}
}
@inproceedings {Simula.simula.2648,
	title = {A Quantitative Analysis of the State of the Art in Quality Provisioning for Multimedia Services Over Next Generation Networks},
	journal = {Proceedings of the 9th ACM international symposium on Mobility management and wireless access},
	year = {2011},
	month = {November},
	pages = {187-190},
	publisher = {ACM},
	type = {Conference},
	abstract = {In this paper, we perform meta-analysis of leading publica- tions in the communication area to dig out the exhausted and least investigated areas within the umbrella of Multi- media quality provisioning. We aggregate the result trends according to an original subject taxonomy, as well as several other relevant classifications (scenario, approach followed, and so on). The main motivation behind this work is to gather information and possibly identify the future research trends on this very important area.},
	keywords = {Conference},
	doi = {10.1145/2069131.2069167},
	author = {Ahmed, Iffat and Badia, Leonardo},
	editor = {Rolim, Jose}
}
@inproceedings {Simula.simula.2644,
	title = {Evaluation of Deficit Round Robin Queue Discipline for Real-Time Traffic Management in an RTP/RTCP Environment},
	journal = {IEEE European Modelling Symposium 2010 (EMS 2010), Pisa, Italy},
	year = {2010},
	pages = {484-489},
	publisher = {IEEE},
	type = {Conference},
	abstract = {Multimedia real-time traffic is deemed to be dominant in future communication systems. One of the reference applications to support real-time traffic is the Real-time Trans- port Protocol (RTP), which can be used to transmit multimedia contents on real-time basis. At the same time, Real-time Transmission Control Protocol (RTCP) is used for receiving feedback and getting information about the network. This paper proposes and evaluates a traffic management implementation in such an RTP/RTCP environment for congestion control. Deficit Round Robin queue discipline is used as the traffic management strategy instead of Random Early Detection and DropTail queue disciplines. A simulation campaign was performed to analyze the effects of implemented traffic strategies in RTP/RTCP environment and compare it with previous solutions. The obtained results highlight a significant difference in terms of jitter delay and packet losses and improvement the bandwidth utilization for real-time flows. Thus, we are able to provide quantitative evidence of the importance of the queue discipline to efficiently manage multimedia content.},
	keywords = {Conference},
	doi = {10.1109/EMS.2010.87},
	author = {Ahmed, Iffat and Badia, Leonardo and Hussain, Khalid},
	editor = {Al-Dabass, David}
}
