Jose Oscar Fajardo

Jose Oscar Fajardo
Universidad del País Vasco / Euskal Herriko Unibertsitatea | UPV/EHU · Department of Communications Engineering

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71
Publications
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618
Citations

Publications

Publications (71)
Thesis
Full-text available
Modern broadband mobile networks such as 4G LTE are designed to cope with stringent performance levels, i.e. considerable peak data rates and low latencies. With the wide-spreading of LTE networks all over the world, the access to Internet services through mobile connections is increasing considerably, leading to a plethora of mobile services. Howe...
Conference Paper
This paper deals with the classical problem of radio resource management in LTE MIMO, with special focus to the specific radio channel characteristics in commercial LTE networks. First, we provide some conclusions about the Channel Quality Information traces obtained through field testing. From this analysis, we perform a series of experiments by m...
Article
Full-text available
IP multimedia subsystem (IMS) is becoming the prevailing candidate for managing future mobile multimedia communications, including critical communications such as public safety, emergency professionals and corporate networks. IMS security and privacy has gained much attention in the few last years. The review of recent IMS security activities stres...
Conference Paper
Nowadays, the Critical Communications networks are experiencing the transformation that will lay the foundations for next decades of emergency communications. Although different forums claim for the benefits of different technological solutions, this evolution seems to be driven towards the adoption of commercial radio technologies and mass market...
Article
This paper deals with the analysis of mobile multimedia services, with special focus on current media resolutions for mobile handsets. Since variable network conditions entail variable quality levels, nowadays several applications implement some kind of dynamic service adaptation in order to mitigate these effects. This paper analyzes the service p...
Conference Paper
Full-text available
The increasing awareness in quality of service (QoS), has brought QoS measuring in Mobile Broadband (MBB) networks to become a key issue. This paper provides with an evaluation of the most significant standardized Internet access measurement methods such as TCP-based and model-based approaches over a controlled testbed and MBB monitoring infrastruc...
Article
Full-text available
5G envisages a "hyper-connected society" where an enormous number of diverse entities could communicate with each other anywhere and at any time, some of which will demand extremely challenging performance requirements such as sub-millisecond latency, and higher data rates. Cloud-enabled radio access networks where intelligence is placed at the edg...
Article
Full-text available
In the context of cloud-enabled 5G radio access networks with network function virtualization capabilities, we focus on the virtual network function placement problem for a multitenant cluster of small cells that provide mobile edge computing services. Under an emerging distributed network architecture and hardware infrastructure, we employ cloud-e...
Article
Taking a look over current mobile implementations, the overhead introduced by the uplink signaling can be prevented reducing the rate of Channel Quality Information reports sent from the mobile users to the channel-aware schedulers located at base stations. In this context, the main goal of the present work is to handle the problem of scheduling tr...
Conference Paper
Full-text available
This paper analyze techniques to implement QoS/QoE on multi-tenant 5G networks. Describes the ar- chitecture of the next generation mobile network based on cloud-enabled small cell deployments and also proposes an hybrid-cloud solution coexisting with centralized cloud RAN(C-RAN), in order to achieve a gradual implementation of the technology. In t...
Conference Paper
This paper focuses on multi-tenant 5G networks with virtualization and mobile edge computing capabilities, in the scope of cloud-enabled small cell deployments. In this context, the work here presented deals with the service management and orchestration challenges that arise when handling service mapping on the multi-tenant distributed cloud-enable...
Article
Full-text available
This paper analyzes current standardization situation of 5G and the role network softwarization plays in order to address the challenges the new generation of mobile networks must face. This paper surveys recent documentation from the main stakeholders to pick out the use cases, scenarios and emerging vertical sectors that will be enabled by 5G tec...
Article
Nowadays, citizens are getting used to new ways of agile communications supporting media-enriched and context-aware information. However, the adoption of these evolved technologies in emergency communications between citizens and public authorities faces a series of barriers, including the lack of harmonized and interoperable solutions. Different i...
Conference Paper
Full-text available
The Cloud Enabled Small Cell (CESC) concept proposed in EU funded project SESAME has emerged as a promising solution to form a multi-tenant, multi-service architecture at the network edge according to 5G needs. It allows several operators/service providers to engage in a sharing model of both radio access capacity and Mobile Edge Computing (MEC) ca...
Article
Full-text available
5G envisages a "hyper-connected society" where trillions of diverse entities could communicate with each other anywhere and at any time, some of which will demand extremely challenging performance requirements such as sub-millisecond low latency. Mobile Edge Computing (MEC) concept where application computing resources are deployed at the edge of t...
Conference Paper
The proper execution of performance tests is of utmost importance for the analysis and evaluation of Internet-related technologies, protocols and deployment strategies. There are plenty of tools available for experimenters ranging from simulation tools, emulation equipment, to small and large scale experimentation testbeds. Each of these performanc...
Article
Full-text available
Hurrengo belaunaldiko sareen kudeaketak eskakizun erronkariei aurre egin behar izango die NFV(Network Function Virtualization), MEC (Mobile Edge Computing) eta SDN (Software Defined Radio) bezalako teknologia gaitzaileen aplikazioaren bitartez. Horrelako kudeaketa egoera konplexuan, adimen artifizialaren erabilpena ziklo kognitibo gisa erreminta ez...
Conference Paper
Adding cognitive capabilities to the wireless networks makes it possible to leverage the control and management information used in the network operation to infer information about the local state and exploit it to improve the overall performance. This paper deals with the combined use of centralized and distributed cognitive cycles integrated at d...
Article
Full-text available
Current trends in broadband mobile networks are addressed towards the placement of different capabilities at the edge of the mobile network in a centralised way. On one hand, the split of the eNB between baseband processing units and remote radio headers makes it possible to process some of the protocols in centralised premises, likely with virtual...
Conference Paper
Full-text available
In this manuscript, we present the main concepts of the 5G-PPP SESAME project dedicated to the implementation of Cloud-Enabled Small Cells (CESCs), able to support edge cloud computing in a multi-tenant, multi-service ecosystem. More particularly, we give a preview of the SESAME concept at the component/sub-system, system and operation level. At th...
Conference Paper
Full-text available
The surge of the Internet traffic with exabytes of data flowing over operators’ mobile networks has created the need to rethink the paradigms behind the design of the mobile network architecture. The inadequacy of the 4G UMTS Long term Evolution (LTE) and even of its advanced version LTE-A is evident, considering that the traffic will be extremely...
Conference Paper
Full-text available
The surge of the Internet traffic with exabytes of data flowing over operators' mobile networks has created the need to rethink the paradigms behind the design of the mobile network architecture. The inadequacy of the 4G UMTS Long term Evolution (LTE) and even of its advanced version LTE-A is evident, considering that the traffic will be extremely...
Article
Full-text available
This article presents a novel architecture for optimizing HTTP-based multimedia delivery in multi-user mobile networks. This proposal combines the usual client-driven dynamic adaptation scheme DASH-3GPP with network-assisted adaptation capabilities, in order to maximize the overall quality of experience. The foundation of this combined adaptation s...
Conference Paper
Full-text available
One of the most challenging problems in mobile broadband networks is how to assign the available radio resources among the different mobile users. Traditionally, research proposals are either specific to some type of traffic or deal with computationally intensive algorithms aimed at optimizing the delivery of general purpose traffic. Consequently,...
Article
Full-text available
A video quality assessment mechanism for next-generation (5G) mobile networks uses the small cell deployment architecture to implement a virtual network function to enable in-service monitoring of delivered video quality.
Article
Most multimedia applications implement some kind of packet losses analysis mechanism to trigger self-adaptation actions. However, error recovery mechanisms such as ARQ variants avoid packet losses at IP level. Then, there appears an impact into the delay that may indeed result on application-level losses due to samples arriving later than the sched...
Conference Paper
This paper deals with the performance evaluation of deploying an IMS-based media plane interoperability framework. The 3GPP standards describe two possible operating modes based on either a reactive or a proactive approach. We show that both approaches entail some advantages and drawbacks in terms of signaling overhead and call setup times at diffe...
Conference Paper
This paper analyzes the scenario where multiple users are trying to transmit the same or related content to a common destination through a shared radio access network. A specific aspect of this study is that all users work for a common objective, as it would be the transmission of critical emergency-related media contents to a central operator. We...
Conference Paper
Full-text available
Currently, the critical communications sector is aware of the need for evolving the portfolio of service capabilities to support advanced multimedia communications in their daily emergency operations. However, there is a discussion about the evolving the private communication networks or adopting commercial network technologies, which have evolved...
Conference Paper
The great technological evolution achieved in the field of public communication networks in comparison to the slower pace of the critical communications sector has raised discussions regarding the next evolutionary steps of PMR technologies and the integration of mission critical aspects into public wideband networks. This paper analyses a converge...
Conference Paper
Emergency telecommunication systems play an important role in people’s daily life, supporting communication for the public and first responders during emergency related incidents. Nonetheless, the majority of existing emergency communications are limited to traditional voice and text message services due to the data bandwidth constraint of current...
Conference Paper
Full-text available
This paper presents a novel open-source implementation of a call center, which is compatible with the IP Multimedia Subsystem (IMS) platform, supporting call forwarding and dispatching services, along with video call and chat with file transfer. The proposed solution is called Call Center for IMS (CC4IMS) and following a requirement analysis, the p...
Article
This paper deals with the subjective quality maximization problem when scheduling multimedia traffic flows in a shared channel. In order to quantify such user satisfaction a utility function dependent on flow transfer delay is used. In this context, we formulate the Quality of Experience aware resource allocation optimization problem as a Markov De...
Article
Full-text available
Scalable video coding allows an efficient provision of video services at different quality levels with different energy demands. According to the specific type of service and network scenario, end users and/or operators may decide to choose among different energy versus quality combinations. In order to deal with the resulting trade-off, in this pa...
Chapter
This chapter proposes a Content-aware and Network-aware Management System (CNMS) over a converged user-environment of social networking and mobile multimedia. The proposed CNMS will focus on applying dynamic personalized multi-layer adaptation for the optimization of the Quality of Experience (QoE) level in a requested media service according to th...
Article
Full-text available
This paper deals with the problem of scheduling mobile Internet traffic over a single cell wireless downlink data channel. On the one hand, we compare the performance of different size-based or/and channel-aware scheduling disciplines in mean delay terms, concluding that an approach that combines both size- and channel-awareness is the best alterna...
Article
Full-text available
This paper deals with the analysis of user perceived visual quality for mobilemultimedia services. H.264/AVC is selected for low resolution video encoding, and a mobile UMTS network is considered for the access to services. First, from subjective tests results, the combined impact of different service– and radio network–level parameters is inferred...
Article
Full-text available
This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and a mobile UMTS network is considered for the access to services. First, from subjective tests results, the combined impact of different service– and radio network–level parameters is inferre...
Conference Paper
This paper deals with the analysis of the impact of different scheduling algorithms on flow level mean delay performance of elastic traffic in a single cell wireless downlink data channel paradigm. An enhanced size-based and channel-aware discipline is proposed, which is based on the sized-aware Gittins index approach applied to a time-varying chan...
Article
Full-text available
The inclusion of multimedia content in different web-based services has increased significantly. Through an extensive subjective testing campaign, we analyse the quality of experience concerning video transmissions associated to these types of services when accessed from mobile devices and mobile Internet connections. Contrary to traditional normal...
Conference Paper
This paper deals with the analysis of user perceived visual quality for mobile multimedia services. H.264/AVC is selected for low resolution video encoding, and 3G UMTS is considered for mobile data services. From subjective tests results, the combined impact of different service- and network-level parameters is inferred. As a result, different cro...
Conference Paper
In this paper, we consider mobile multimedia services delivered over a UMTS network. In this convergent scenario, low level error recovery mechanisms of the access network entail that almost all packet losses are caused by frames arriving at the receiver later than the playout time. Our aim is to find a simplified yet realistic expression for the s...
Conference Paper
The aim of this paper is to assess the impact of devices on Quality of Experience (QoE) of the user. As the types of video content viewed over handheld devices increases e.g. streaming video, it is important to evaluate the impact of the end device on video quality assessment. In this paper subjective tests were conducted with QCIF (176×144) videos...
Conference Paper
This paper deals with the analysis of user perceived visual quality for broadcast mobile TV services, considering energy constraints of mobile devices. An enhanced broadcast multi-layering video transmission scheme is proposed to cope with the heterogeneity of mobile devices capabilities, which enables mobile devices to achieve energy savings in ac...
Article
Most of the currently available adaptation solutions of VoIP over UMTS are based on the modification of service parameters as the only available reaction against any detected service degradation. On the contrary, in this paper we propose a combined approach where service-level adaptation is considered first and, provided that no suitable parameter...
Conference Paper
In Universal Mobile Telecommunication System (UMTS) Radio Link Control (RLC) losses severely affect the Quality of Service (QoS) due to high error probability. Therefore, for any video quality prediction model, it is important to model the radio-link loss behaviour. In this paper we evaluate the impact of the radio access network on the end-to-end...
Conference Paper
The Quality of Service (QoS) of Universal Mobile Telecommunication System (UMTS) is severely affected by the losses occurring in Radio Link Control (RLC) due to high error probability. Therefore, for any video quality prediction model, it is important to model the radio-link loss behaviour appropriately. In addition, video content has an impact on...
Conference Paper
Universal Mobile Telecommunication System (UMTS) is a third generation mobile communication systems that supports wireless wideband multimedia applications. The objective of this paper is to present a new model for non-intrusive prediction of H.264 encoded video quality over UMTS networks and to illustrate their application to video quality monitor...
Article
Full-text available
The aim of this paper is to present video quality prediction models for objective non-intrusive, prediction of H.264 encoded video for all content types combining parameters both in the physical and application layer over Universal Mobile Telecommunication Systems (UMTS) networks. In order to characterize the Quality of Service (QoS) level, a learn...
Chapter
This chapter proposes a Content-aware and Network-aware Management System (CNMS) over a converged user-environment of social networking and mobile multimedia. The proposed CNMS will focus on applying dynamic personalized multi-layer adaptation for the optimization of the Quality of Experience (QoE) level in a requested media service according to th...
Conference Paper
Full-text available
The provision of video streaming services over mobile data accesses is emerging as a promising service for the current and future Internet. This paper focuses on the study of H.264-based video contents over a typical 3G UMTS connectivity. The performance of the service is finally determined by the combined effects of the encoding features and the r...
Article
Full-text available
HSDPA defines a new High Speed Shared Channel (HS-DSCH) which allows for practical speeds up to 10 Mbps. Among all the changes introduced by HSDPA, the most prominent ones regarding QoS are the inclusion of “link adaptation”, “Hybrid ARQ” and the quick “Scheduling” algorithms. In HSDPA the Radio Network Controller (RNC) is still the responsible for...
Conference Paper
Full-text available
This paper evaluates the performance of VoIP services over mobile accesses, with special focus on currently deployed Best Effort UMTS networks. There are different configuration parameters that have a great impact on end users' perception of quality. This paper tries to help understanding the impact of those parameters, and how they can be tuned fo...
Conference Paper
This paper shows the relevance of implementing a dynamic and real-time Voice over IP (VoIP) service adaptation mechanism in order to avoid Perceived Quality of Service (PQoS) degradations. We have studied the most relevant parameters affecting the PQoS experienced by end users in VoIP services over mobile accesses. We will describe the enhancements...
Conference Paper
Full-text available
Future Internet will have to cope with yet unknown terminals and services (even users), in a number and heterogeneity never seen before. So, flexibility or adaptability will be considered as one of the most important design principles. This flexibility will demand different kinds of awareness both in the ends and in every node in the service supplyin...
Conference Paper
Full-text available
In this paper we present an implementation and validation tests that allow a GNU/Linux node act as a PE router in a BGP/MPLS IP VPN architecture. Precisely, this implementation supports all the mandatory capabilities defined in RFC 4364 with regard to the data forwarding plane, such as VRFs to separate the traffic from different VPNs, MPLS to manag...
Conference Paper
Full-text available
This paper presents an implementation of the BGP/MPLS IP VPN functionalities for GNU/Linux. First, we briefly review the operation mode described in the IETF RFC 4364 and show the characteristics that are supported by this implementation. Afterwards, we provide some implementation details of the forwarding plane for the kernel 2.6.18.1. This implem...
Conference Paper
Full-text available
Traditional QoS related studies handle technical KPI (key performance indicators) which are supposed to measure the quality of telecommunication services. However, while trying to select an ISP, most users are not able to select the most suitable one for their needs. This paper presents the application of a perceived QoS based model as a tool for h...
Chapter
Full-text available
This paper proposes a service discovery protocol for discovering and advertising services in a proactive ad hoc network. The protocol we have defined is piggybacked into the OLSR protocol. We define a new message type into OLSR called Service Discovery Message (SDM) for both advertisement and discovery of services. The advertisement frequency and a...
Conference Paper
This paper deals with the management of QoS as perceived by end users in corporate networks. First, we overview some previous results achieved by the research group in the field of estimating and managing the QoS. In this work we accomplished some validation tasks by means of simulation. Going on with the analysis of applicability of the general mo...
Conference Paper
This paper presents a comprehensive model intended to analyze quality of service in telecommunications services and its causes. Although many works have been published in this area, both from a technical viewpoint as well as taking into consideration subjective concerns, they have not resulted in a unique methodology to assess the experienced quali...
Conference Paper
In last years there have been some governmental initiatives aimed at the regulation of quality of service evaluation in telecommunications services. However this has proven to be a complex task especially for Internet services, where it is difficult to objectively assess the quality of a service and to identify whether one or more of the provider a...