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  • On the need for dynamic downlink intercell interference coordination for realistic long term evolution deployments

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    Wireless communications and mobile computing
    Date of publication: 2014-03
    Journal article

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    Intercell interference is the main issue limiting the capacity of modern orthogonal frequency-division multiple access based cellular networks. Recently, extensive research work has been carried out in this field, and intercell interference coordination techniques have been recognized as key enablers of current (and future) cellular technologies. In this article, (i) a comprehensive survey of the most representative contributions is provided together with (ii) a generic methodology to measure their actual merit. The performance of several interference avoidance strategies has been evaluated both from system and user point of view in the context of a Long Term Evolution (LTE)-based network considering not only synthetic cellular scenarios but also realistic deployments. Our literature review indicates that there is a need for adaptive/operatorcustomizable low-complex intercell interference coordination (ICIC) schemes suitable for realistic LTE deployments. Results obtained by means of a comprehensive set of simulations corroborate and support this premise. In this article, it is shown that simultaneous gains in terms of spectral/energy efficiency and fairness can be achieved through dynamic mechanisms with respect to both classic hard reuse schemes and static ICIC techniques. Besides numerical results, a novel merit assessment methodology based on several weighted performance metrics is proposed. Our findings show that dynamic schemes outperform static techniques by around 20–35% in realistic deployments.

  • Analytical modeling and performance evaluation of cell selection algorithms for mobile networks with backhaul capacity constraints

     Olmos Bonafé, Juan José; Ferrús Ferré, Ramon; Galeana Zapien, Hiram
    IEEE transactions on wireless communications
    Date of publication: 2013-10-28
    Journal article

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    Mobile backhaul has moved to the forefront of wireless industry hot topics. The progressive deployment of spectrally efficient radio access technologies (e.g. HSPA, LTE, WiMAX) in mobile broadband is turning into stringent capacity requirements on the backhaul network. This makes backhaul capacity to become a potential network bottleneck in some deployment scenarios. While more cost-efficient transmission technologies are needed to increase the capacity of mobile backhaul, optimization solutions to get the most out of the backhaul capacity are also necessary. This paper analyses the possibility to exploit load balancing among base stations to improve backhaul capacity utilization. Load balancing is realized through cell selection algorithms accounting for both radio interface and backhaul conditions. An analytical model aimed at evaluating the performance of cell selection strategies for mobile networks with backhaul capacity constraints is developed. The analytical model is used to evaluate the performance of a novel backhaul-aware cell selection algorithm and compare it with classical schemes based exclusively on radio information. Obtained results show that the proposed algorithm can achieve a utilization of backhaul resources higher than the traditional cell selection schemes while providing the same radio interface performance. Analytical results have been verified by means of simulation.

  • Link abstraction for variable bandwidth with incremental redundancy HARQ in LTE

     Latif, Imra; Kaltenberger, Florian; Knopp, Raymond; Olmos Bonafé, Juan José
    International Symposium on Modeling and Optimization in Mobile, Ad Hoc and Wireless Networks
    Presentation's date: 2013-05
    Presentation of work at congresses

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    Incremental redundancy hybrid automatic repeat request (IR-HARQ) scheme used in recent wireless communication standards such as 3GPP LTE provides higher benefits in terms of system capacity and robustness. To map these benefits into system level evaluations is of critical importance. Traditional link abstraction techniques are usually designed for a fixed bandwidth and do not present a generic solution for the variable bandwidth assignment to the users. Therefore in this paper we propose a generic methodology for modeling the IR-HARQ link performance in LTE for the system level simulators. The proposed scheme allows for the arbitrary bandwidth assignments while at the same time reduces the storage requirement for the complex operations of IR-HARQ link abstraction. We apply the proposed methodology to a wide variety of the modulation and coding schemes (MCS) in LTE for a highly frequency selective channel and show that the proposed model provides accurate results.

    Incremental redundancy hybrid automatic repeat request (IR-HARQ) scheme used in recent wireless communication standards such as 3GPP LTE provides higher benefits in terms of system capacity and robustness. To map these benefits into system level evaluations is of critical importance. Traditional link abstraction techniques are usually designed for a fixed bandwidth and do not present a generic solution for the variable bandwidth assignment to the users. Therefore in this paper we propose a generic methodology for modeling the IR-HARQ link performance in LTE for the system level simulators. The proposed scheme allows for the arbitrary bandwidth assignments while at the same time reduces the storage requirement for the complex operations of IR-HARQ link abstraction. We apply the proposed methodology to a wide variety of the modulation and coding schemes (MCS) in LTE for a highly frequency selective channel and show that the proposed model provides accurate results.

  • Improved scheduling decisions for LTE-A uplink based on MPR information

     Lema, Maria A.; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    European Cooperative in Science And Technology
    Presentation's date: 2013-02-07
    Presentation of work at congresses

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    Advanced (LTE-A) allows for non-contiguous resource allocation in the uplink. The aim is to increase the spectral efficiency by exploiting users’ frequency diversity gain. This feature implies that clustered-DFT-S-OFDM must be used in the uplink, no longer preserving the single carrier property of previous releases. Multi-cluster transmission brings an increase in the signal’s Peak-to-Average Power Ratio (PAPR) and so power de-rating must be introduced to control out-of-band emissions. Maximum power Reduction (MPR) can counteract the frequency gain and bring losses to the users’ performance. This paper proposes a novel scheduler that considers the MPR information. The packet scheduler’s main task is to evaluate the gain or loss in throughput of the multi-cluster transmission over a conventional contiguous one. Based on the Sounding Reference Signals (SRSs) channel estimation, the eNB can predict the multi- cluster transmission’s performance. Results show that enabling the MPR information in the scheduler adapts the transmission mode to each particular case, enhancing the system throughput

  • Improved scheduling techniques for efficient uplink communications with carrier aggregation

     Lema Rosas, Maria Angel; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    Workshop on SON Algorithms for Energy Efficiency
    Presentation's date: 2013-05-28
    Presentation of work at congresses

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    Transmitted power in Long Term Evolution - Advanced (LTE-A) uplink (UL) is strongly related to the number of physical resource blocks (PRBs) allocated. As the transmitted bandwidth increases power does so. However, this rise in power is also required to increase throughput. It is necessary to create efficient techniques that allows sending more information (bits) with the same power requirements. Against previous LTE releases, LTE-A allows the use of non-contiguous resource allocation in the UL together with the simultaneous transmission along multiple component carriers named, carrier aggregation. These features lead to an increase in spectral efficiency thanks to ling performance gains obtained from frequency diversity. This work studies the effect of scheduling techniques on the throughput performance and power consumption of users. Results show that cell edge performance is very sensitive to the scheduling decisions, therefore, limitations in bandwidth are introduced in order to reduce power consumption and improve throughput. Carrier Aggregation turns out to be more efficient as users can be classified and improve spectral and energy efficiency.

  • On the performance of LTE UL power control in realistic conditions

     Lema Rosas, Maria Angel; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering (LNICST)
    Date of publication: 2013-05-07
    Journal article

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    This paper deals with the interference control in the uplink (UL) of Long Term Evolution (LTE) systems. Although the multiple access technique allows an almost null intra-cell interference, the system is still sensitive to the inter-cell component caused by neighbouring cells. The UL power control proposed by the 3GPP is a means to reduce this interference. In this sense, user equipments (UE) establish an operation point (open loop power control or OLPC) to compensate the mean path loss and its slow variations. Additionally, this may be fine tuned by specific commands (closed loop). The current paper focuses on the performance of OLPC when deployed in realistic scenarios where heterogeneity is a key feature, both in the deployment of sites and in the concentration of users. The investigation is done in a comparative way, against a classic synthetic and regular scenario. Results indicate that the performance of the OLPC differs from the theoretical environment, due to the difference in the scenario nature. The summation of indoor coverage and guided path-loss results the urban scenario OLPC optimal point to lie in between two limits, one established by the reduced transmitted power fixed by the OLPC and the other by the interferences.

  • MIMO and next generation systems

     Burr, Alister; Burciu, Ioan; Chambers, Pat; Javornik, Tomaz; Kansanen, Kimmo; Olmos Bonafé, Juan José; Piestch, Christian; Sykora, Jan; Teich, Werner; Villemaud, Guillaume
    Date of publication: 2012
    Book chapter

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  • On the use of mutual information at bit level for accurate link abstraction in LTE with incremental redundancy H-ARQ

     Olmos Bonafé, Juan José; Serra, Albert; Ruiz Boque, Silvia; Latif, Imran
    European Cooperative in Science And Technology
    Presentation's date: 2012-09-25
    Presentation of work at congresses

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    Link abstraction methods are able to predict the BLER in multicarrier wideband systems using AMC techniques under multipath fading. The basic idea is to map the vector of the subcarrier SNR’s to a single scalar, the Effective SNR (ESNR), which is then used to predict the BLER. This procedure is important during real system operation, since the mobile terminal must report the Channel Quality Indicator (CQI) to the base station, and also for the system level simulators. In order to take into account H-ARQ, it is also interesting to predict the BLER after one or more IR retransmissions have happened. With IR H-ARQ there is an additional complexity, since the BLER performance of a given redundancy version (rv) depends on the SNR experienced by the receiver at current rv but also on the SNR of previously received rv's. We propose a novel link abstraction method that can predict the BLER with good accuracy in multipath fading and including the effects of H-ARQ retransmissions. The proposed method is based on estimating the mutual information between the transmitted bits and the received LLRs. We show that, by working at bit level, the effect of unequal error protection in 16 and 64QAM modulations is properly captured without resorting to any set of calibration constants. We also show how to reduce the set of reference BLER curves when working with multiple modulation and code schemes (MCS). Simulation results for LTE downlink with SISO transmission mode are included in the paper.

  • A novel ICIC-oriented channel state information feedback scheme for aperiodic reporting in LTE

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    European Cooperative in Science And Technology
    Presentation's date: 2012-02-08
    Presentation of work at congresses

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    In moderm OFDMA-based cellular networks, intercell interference is the main issue limiting the capacity of these systems. Recently, intensive research work has been focused on intercell interference coordination as it has been recognized as an important element to achieve seamless levels of quality of service. However, in most of the cases, this issue is addressed as a standalone issue. In this work, a novel channel state information feedback mechanism is proposed aiming at improving the system performance when static interference coordination techniques are also considered. By means of the proposed scheme, gains in terms of (1) users throughput, (2) cell edge performance and (3) energy efficiency are achieved with respect to existing aperiodic LTEbased mechanisms. Moreover, given the low complexity of the proposed solution, feasibility aspects are also discussed and a possible LTE implementation alternative is suggested.

  • An analytical view of static intercell interference coordination techniques in OFDMA networks

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    IEEE Wireless Communications and Networking Conference
    Presentation's date: 2012-04-02
    Presentation of work at congresses

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    This paper presents a novel methodology to assess the downlink performance of static intercell interference coordination techniques in the context of OFDMA-based cellular networks. In the last few years, interference mitigation techniques have been considered a research topic of utmost importance since intercell interference is the main issue limiting the capacity of modern cellular technologies such as LTE and WiMAX. The methodology presented in this paper should be understood not only as an analytical shortcut to foresee overall network interference conditions but also a mean to properly establish bounds to parameters associated to static intercell interference techniques operation. Moreover, the analysis allows to take into account both local large scale fading particularities and mobile operators’ preferences. In this sense, results show how the resulting set of preferred operational points is in general operatordependent and hence, the usefulness of the proposed framework is established.

  • Improving channel state information feedback for static Intercell interference coordination in LTE

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    IEEE International Conference on Communications
    Presentation's date: 2012-06-12
    Presentation of work at congresses

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    Intercell Interference is the main issue limiting the capacity of modern OFDMA-based cellular networks. Recently, extensive research work has been focused on intercell interference coordination since it has been recognized as a key concept to achieve seamless levels of quality of service. Nevertheless, very often this problematic is addressed as a standalone issue. In this work, a novel channel state information feedback scheme is proposed aiming at improving the overall system performance when both channel state information and static interference coordination are jointly considered. By means of the proposed scheme, gains in terms of users throughput, cell edge performance and energy efficiency are achieved with respect to existing aperiodic LTE-based mechanisms without additional complexity.

  • On the role of downlink control information in the provision of QoS for NRT services in LTE

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    IEEE Vehicular Technology Conference
    Presentation's date: 2012-05-07
    Presentation of work at congresses

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    The provision of Quality of Service (QoS) to users of LTE networks depends to a large degree on the choice of an appropriate scheduling algorithm able to meet the requirements of mobile operators. Dynamic packet scheduling has been recognized as a key approach to maximize the utility of OFDMAbased systems due to its inherent ability to exploit the frequency selectiveness of wideband channels both in time and frequency domain. However, one of the main issues associated to dynamic scheduling is the high amount of signaling overhead required to provide users with resource allocation information. While the impact of control channel limitations on LTE VoIP capacity has been widely studied yet, tradeoffs associated to control channel usage and the provision of QoS for Non-Real Time (NRT) services has been basically omitted in current literature. In this paper, such tradeoffs have been addressed from several perspectives. Results show that the relationship between scheduling policies, offered levels of QoS (expressed in terms of guaranteed bit rates) and control channels capacity is not trivial and requires careful planning.

  • Modelling channel estimation error in LTE link level simulations

     Serra, Albert; Olmos Bonafé, Juan José; Lema Rosas, Maria Angel
    European Cooperative in Science And Technology
    Presentation's date: 2012-02-08
    Presentation of work at congresses

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    Channel estimation is a key aspect for the performance of the physical layer in all MIMO-OFDM systems. In order to obtain realistic performance assessments from the LTE link level simulator, channel estimation errors must be taken into account. Implementing a detailed channel estimation algorithm may lead to long simulation time, in particular for wideband MIMO transmission modes where many channels have to be estimated, and for procedures like Wiener filtering which require matrix multiplications. In this paper we propose to simulate channel estimation errors by a Gaussian additive noise error model. The noise variance of the model is calibrated as a function of the received SNR for different channel models and Doppler spreads. The model is validated by comparing the BLER curves obtained with the model with the curves obtained when using real channel estimation.

  • Optimization of realistic full frequency reuse OFDMA-based cellular networks

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José; Lee, Dong Seop
    IEEE International Symposium on Personal Indoor and Mobile Radio Communications
    Presentation's date: 2012-09-09
    Presentation of work at congresses

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    Nowadays mobile operators are planning and de- signing their mid/long term strategies based on new OFDMA- based cellular technologies such as LTE and WiMAX. Co-siting and re-utilization of existing facilities are within their roadmap in order to keep CAPEX as low as possible. Therefore, the optimization of OFDMA networks subject to fixed/previous (and usually suboptimal) coverage is mandatory. In addition, recently there is a great interest in reducing OPEX mainly by means of energy savings. This paper presents a novel multiobjective formulation aiming at improving the performance of OFDMA networks where full frequency reuse is employed. The proposed framework is flexible and results indicate that it is also effective as it improves both spectral efficiency and cell edge performance while it simultaneously reduces energy consumption.

  • On the performance of LTE UL power control in realistic conditions

     Lema, Maria A.; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    International ICST Conference on Mobile Networks and Management
    Presentation's date: 2012-09-24
    Presentation of work at congresses

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  • Admission control in LTE uplink systems with sounding reference signals based channel state indicator

     Lema, Maria A.; Ramon Ferran, Sergi; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    European Cooperative in Science And Technology
    Presentation's date: 2012-02-08
    Presentation of work at congresses

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    This article focuses on the investigation of the Admission Control techniques in order to assure Quality of Service (QoS) in Long Term Evolution (LTE) systems. So as to estimate the users bandwidth requirement, Sounding Reference Signals (SRS) bandwidth are allocated to each user in order to have accurate up-to-date channel state information at the evolved Node B (eNB). Since User Equipments (UEs) are power limited, several SRS are required to scan the full bandwidth for UEs with high path loss. Therefore, in order to own reliable information the eNB must trade-off up-to-date information and accuracy of the measurement. This paper investigates a novel way in which the eNB measures the users radio requirements in order to accomplish QoS, using the information on the SRS already known by the eNB. This measurement technique is compared against two models presented in [1], first a reference AC model in which users are accepted up to a cell bit-rate limit, and a second one proposed by the authors in which the users requirements are estimated using the power control formula and the Shannon capacity. The methodology followed is based on system level simulations. Results show that the SRS based AC is more optimist when estimating users channel conditions and therefore more users are accepted to the system, increasing the overall cell throughput when compared to the power control based algorithm.

  • Improving the Interplay between Periodic Channel State Information Feedback and Static Intercell Interference Coordination in LTE

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    Journal of communications
    Date of publication: 2012-09-01
    Journal article

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  • Comparison of multicast/broadcast services in long term evolution advanced and IEEE 802.16m networks

     Calabuig Gaspar, Jorge; Monserrat del Río, José Francisco; Martín-Sacristán Gandía, David; Olmos Bonafé, Juan José
    Wireless communications and mobile computing
    Date of publication: 2012-03-21
    Journal article

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    This paper performs a comparison of multicast/broadcast services (MBS) support in Long Term Evolution Advanced (LTE-A) and Worldwide Interoperability for Microwave Access (WiMAX) IEEE 802.16m. Firstly, the main technical features of both standards concerning MBS operation are presented. It is shown that WiMAX offers higher unicast/MBS multiplexing flexibility as it supports both frequency and time multiplexing schemes, whereas LTE-A only includes time multiplexing. Besides, onlyWiMAX supports multi-antenna transmission. Next, the results of two simulation-based assessments are presented. In the former, it is considered a scenario with all cells transmitting the same MBS service. The effect of inter-site distance (ISD) on themaximum MBS data rate is evaluated. Results show thatWiMAXconfigurations outperform LTE-A for small ISD. This is becauseWiMAX provides a higher number of resources dedicated to data transmission for the same bandwidth. Furthermore, some WiMAX configurations support two spatially multiplexed data streams. With higher ISDs, LTE-A outperforms single-stream WiMAX configurations. In the second assessment, a MBSFN area surrounded by interfering cells is considered to compare unicast/MBS multiplexing performance. The higher maximum MBS data rate is achieved inWiMAX with time division multiplexing, which is precisely the only alternative included in LTE-A

  • Comunicaciones móviles eficientes basadas en redes heterogéneas y coordinación de interferencias

     Garcia Lozano, Mario; González González, David; Laya Romero, Andres Ernesto; Pérez Diaz de Cerio, David; Valenzuela Gonzalez, Jose Luis; Lema Rosas, Maria Angel; Ruiz Boque, Silvia; Alonso Zárate, Luis Gonzaga; Olmos Bonafé, Juan José
    Participation in a competitive project

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  • Simulation of LTE IR H-ARQ at system level using MIESM error prediction

     Olmos Bonafé, Juan José; Serra, Albert; Garcia Lozano, Mario; Ruiz Boque, Silvia; Pérez Diaz de Cerio, David
    European Cooperative in Science And Technology
    Presentation's date: 2011
    Presentation of work at congresses

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  • LTE UL power control evaluation in a system level simulator for synthetic and realistic scenarios

     Lema, Maria A.; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José; Pérez Diaz de Cerio, David
    European Cooperative in Science And Technology
    Presentation's date: 2011-10-19
    Presentation of work at congresses

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    The research involved in this study comprises the analysis of the impact of the power control algorithm and its performance in the system level. Following our work in TD 01040, the LTE system level simulator has been equipped with a power control block that enables interference management at the same time that controls the fairness among users. Rising from the fact that it is very sensitive to the environment, the algorithm is tested in two different scenarios in a comparative way. First, the conventional synthetic scenario, with regular hexagonal base stations distribution, and then a piece of the scenario of Vienna, developed during the COST 273 action in the MORANS initiative. This dissimilarity in simulation environment leads to strong differences in the system performance. Results show how the real scenario is not so sensitive to interferences and so that the major issue is the availability of transmission power at the cell edge.

  • Impact of downlink signaling capacity constraints on the provision of QoS in LTE

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    European Cooperative in Science And Technology
    Presentation's date: 2011-10-19
    Presentation of work at congresses

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    Choosing appropriate scheduling policies is of utmost importance to deliver acceptable levels of Quality of Service (QoS) to users of LTE networks. This decision is not only conditioned by the type of services expected to be offered but also by targeted QoS levels properly said. In this sense, preliminary performance evaluations depend to a large degree on the accuracy with which relevant practical system limitations are modelled. In LTE, the capacity of control channels is clearly one of the most important issues. While the impact of control channel limitations on LTE VoIP capacity has been widely studied yet, tradeoffs associated to control channel usage and the provision of QoS for Non-Real Time (NRT) services has been basically omitted in current literature. In this paper, several experiments have been conducted to investigate such interplay from different points of view. Results show that the relationship between scheduling policies, offered levels of QoS (expressed in terms of guaranteed bit rates) and control channels capacity is not trivial and requires careful planning.

  • Uplink system and link level simulation of 3GPP-LTE Rel. 8

     Lema, Maria A.; Garcia Lozano, Mario; Olmos Bonafé, Juan José; Ruiz Boque, Silvia
    European Cooperative in Science And Technology
    Presentation's date: 2011-06-20
    Presentation of work at congresses

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  • On the performance of static inter-cell interference coordination in realistic cellular layouts

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    Lecture Notes of the Institute for Computer Sciences, Social-Informatics and Telecommunications Engineering (LNICST)
    Date of publication: 2011-05-25
    Journal article

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  • Contribution to resource management in cellular acces networks with limited backhaul capacity

     Galeana Zapien, Hiram
    Defense's date: 2011-02-25
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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  • Contribution to resource management in cellular access networks with limited backhaul capacity  Open access

     Galeana Zapien, Hiram
    Defense's date: 2011-02-25
    Department of Signal Theory and Communications, Universitat Politècnica de Catalunya
    Theses

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    La interfaz radio de los sistemas de comunicaciones móviles es normalmente considerada como la única limitación de capacidad en la red de acceso radio. Sin embargo, a medida que se van desplegando nuevas y más eficientes interfaces radio, y de que el tráfico de datos y multimedia va en aumento, existe la creciente preocupación de que la infraestructura de transporte (backhaul) de la red celular pueda convertirse en el cuello de botella en algunos escenarios. En este contexto, la tesis se centra en el desarrollo de técnicas de gestión de recursos que consideran de manera conjunta la gestión de recursos en la interfaz radio y el backhaul. Esto conduce a un nuevo paradigma donde los recursos del backhaul se consideran no sólo en la etapa de dimensionamiento, sino que además son incluidos en la problemática de gestión de recursos. Sobre esta base, el primer objetivo de la tesis consiste en evaluar los requerimientos de capacidad en las redes de acceso radio que usan IP como tecnología de transporte, de acuerdo a las recientes tendencias de la arquitectura de red. En particular, se analiza el impacto que tiene una solución de transporte basada en IP sobre la capacidad de transporte necesaria para satisfacer los requisitos de calidad de servicio en la red de acceso. La evaluación se realiza en el contexto de la red de acceso radio de UMTS, donde se proporciona una caracterización detallada de la interfaz Iub. El análisis de requerimientos de capacidad se lleva a cabo para dos diferentes escenarios: canales dedicados y canales de alta velocidad. Posteriormente, con el objetivo de aprovechar totalmente los recursos disponibles en el acceso radio y el backhaul, esta tesis propone un marco de gestión conjunta de recursos donde la idea principal consiste en incorporar las métricas de la red de transporte dentro del problema de gestión de recursos. A fin de evaluar los beneficios del marco de gestión de recursos propuesto, esta tesis se centra en la evaluación del problema de asignación de base, como estrategia para distribuir el tráfico entre las estaciones base en función de los niveles de carga tanto en la interfaz radio como en el backhaul. Este problema se analiza inicialmente considerando una red de acceso radio genérica, mediante la definición de un modelo analítico basado en cadenas de Markov. Dicho modelo permite calcular la ganancia de capacidad que puede alcanzar la estrategia de asignación de base propuesta. Posteriormente, el análisis de la estrategia propuesta se extiende considerando tecnologías específicas de acceso radio. En particular, en el contexto de redes WCDMA se desarrolla un algoritmo de asignación de base basado en simulatedannealing cuyo objetivo es maximizar una función de utilidad que refleja el grado de satisfacción de las asignaciones respecto los recursos radio y transporte. Finalmente, esta tesis aborda el diseño y evaluación de un algoritmo de asignación de base para los futuros sistemas de banda ancha basados en OFDMA. En este caso, el problema de asignación de base se modela como un problema de optimización mediante el uso de un marco de funciones de utilidad y funciones de coste de recursos. El problema planteado, que considera que existen restricciones de recursos tanto en la interfaz radio como en el backhaul, es mapeado a un problema de optimización conocido como Multiple-Choice Multidimensional Knapsack Problem (MMKP). Posteriormente, se desarrolla un algoritmo de asignación de base heurístico, el cual es evaluado y comparado con esquemas de asignación basados exclusivamente en criterios radio. El algoritmo concebido se basa en el uso de los multiplicadores de Lagrange y está diseñado para aprovechar de manera simultánea el balanceo de carga en la intefaz radio y el backhaul.

  • An early stage training network in enabling technologies for GREEN radio

     Laya Romero, Andres Ernesto; Kartsakli, Elli; Olmos Bonafé, Juan José; Ruiz Boque, Silvia; Valenzuela Gonzalez, Jose Luis; Collado Gomez, Juan Carlos; Garcia Lozano, Mario; Alonso Zárate, Luis Gonzaga; Pérez Diaz de Cerio, David
    Participation in a competitive project

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  • 3GPP LTE: hacia la 4G móvil

     Cardona, Narcís; Olmos Bonafé, Juan José; Garcia Lozano, Mario; Monserrat, José F.; Cabrejas Peñuelas, Jorge; Calabuig Soler, Daniel; Fernández Aguilella, Ana; González González, David; Martín-Sacristán Gandía, David; Ruiz Boque, Silvia
    Date of publication: 2011-04-01
    Book

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    Static inter-cell interference coordination techniques for LTE networks: a fair performance assessment  Open access

     González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    International Workshop on Multiple Access Communications
    Presentation's date: 2010-09-14
    Presentation of work at congresses

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    Link abstraction models based on mutual information for LTE downlink  Open access

     Olmos Bonafé, Juan José; Ruiz Boque, Silvia; Garcia Lozano, Mario; Martín Sacristán, David
    European Meeting COST 2100. Pervasive Mobile & Ambient Wireless Communications
    Presentation of work at congresses

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    Postprint (author’s final draft)

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    Metaheuristic proposal to minimize self-interference in single frequency networks  Open access

     Garcia Lozano, Mario; Ruiz Boque, Silvia; Lema, Maria A.; Torras, Evelyn; Olmos Bonafé, Juan José; Minerva, Flaminio
    European Meeting COST 2100. Pervasive Mobile & Ambient Wireless Communications
    Presentation of work at congresses

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  • Performance evaluation of static inter-cell interference coordination in realistic cellular layouts

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    European Cooperation in the Fiel of Scientific and Techinical Research
    Presentation of work at congresses

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    Effective interference management has been recognized by the industry and standardization bodies as a key enabler for 4G systems. This work is about static Inter-Cell Interference Coordination for OFDMA based cellular networks such as LTE. The majority of previous ICIC studies, both theoretical and simulation-based, have been conducted considering synthetic and/or small cellular layouts. In this work, the performance of static ICIC strategies in non-regular cellular layout is studied introducing some related RRM functions in the methodology. The overall performance assessment gives special attention to the efficiency vs. fairness tradeoff and the elements associated to it. Results show that the design of suitable and effective ICIC schemes for realistic cellular networks can not be done by simply extending classical approaches.

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    Performance evaluation of downlink interference coordination techniques in LTE networks  Open access

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José; Corvino, Virginia
    IEEE Vehicular Technology Conference
    Presentation's date: 2010-09-09
    Presentation of work at congresses

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  • On the performance of static inter-cell interference coordination in realistic cellular layouts

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    International ICST Conference on Mobile Networks and Management
    Presentation's date: 2010-09-23
    Presentation of work at congresses

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    Effective interference management has been recognized by the industry and standardization bodies as a key enabler for 4G systems. This work is about static Inter-Cell Interference Coordination for OFDMA based cellular networks such as LTE. The majority of previous ICIC studies, both theoretical and simulation-based, have been conducted considering synthetic and/or small cellular layouts. In this work,the performance of static ICIC strategies in non-regular cellular layout is studied introducing some related RRM functions in the methodology. The overall performance assessment gives special attention to the efficiency vs. fairness tradeoff and the elements associated to it. Results show that the design of suitable and effective ICIC schemes for realistic cellular networks can not be done by simply extending classical approaches.

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    SDR in undergraduate engineering education  Open access

     Marojevic, Vuk; Gomez Miguelez, Ismael; Olmos Bonafé, Juan José; Montoro López, Gabriel; Gelonch Bosch, Antoni
    Wireless Innovation Forum Conference on Communications Technologies and Software Defined Radio
    Presentation's date: 2010-11-30
    Presentation of work at congresses

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  • Static Inter-cell interference coordination techniques for LTE networks: a fair performance assessment

     González González, David; Garcia Lozano, Mario; Ruiz Boque, Silvia; Olmos Bonafé, Juan José
    Lecture notes in computer science
    Date of publication: 2010-09-13
    Journal article

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    This paper focuses in the analysis of 100% static and distributed inter-cell interference coordination techniques in the context of LTE networks. Several methods have been modeled and studied with the aim of deriving practical radio planning rules based on the joint effect of operational parameters and thresholds. The investigation places special emphasis on the efficiency vs. fairness tradeoff through a set of metrics that allow not only to evaluate the measurements from different points of view, but also to look at the effectiveness in radio resources usage. Results show that similar levels of spectral efficiency can be achieved by means of a proper and accurate network tuning. Moreover, interesting second order differences appear due to inherent features of each approach. These can be exploited depending on the particular network operator needs.

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    Comparison of different distributed scheduling strategies for static/dynamic LTE scenarios  Open access

     Ruiz Boque, Silvia; Haro, Eva; González González, David; Garcia Lozano, Mario; Olmos Bonafé, Juan José
    European Meeting COST 2100. Pervasive Mobile & Ambient Wireless Communications
    Presentation's date: 2009-09-29
    Presentation of work at congresses

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  • Downlink Resource Allocation in LTE: Centralized vs. Distributed Approach

     González González, David; Corvino, Virginia; Ruiz Boque, Silvia; Olmos Bonafé, Juan José; Garcia Lozano, Mario; Verdone, Roberto
    Joint COST2100 - NewCom++ workshop on "Radio Resource Assignment for LTE
    Presentation's date: 2009-09-30
    Presentation of work at congresses

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    The 3GPP specifications for LTE leave many degrees of freedom to operators about how to design radio Resource Allocation (RA) strategies, and this is actually also allowed by the OFDM/OFDMA access technology. This means that RA can be faced from many points of view, motivating the research in several directions. In fact, it is clear that both centralized and distributed schemes appear as two valid alternatives to effectively manage radio resources from a multi-cell perspective in order to cope with the requirements imposed by applications and users by keeping inter-cell interference under control. The objective of this paper is to compare via simulation these two approaches under the same network conditions, in terms of users distribution, channel realizations, traffic models, taking into account a complex realistic scenario. Performance will be evaluated in terms of user throughput and power consumption, and some conclusions on advantages and drawbacks of each approach will be drawn.

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    Exponential effective SIR metric for LTE downlink  Open access

     Olmos Bonafé, Juan José; Serra, Albert; Ruiz Boque, Silvia; Garcia Lozano, Mario; González González, David
    IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications
    Presentation's date: 2009-09-16
    Presentation of work at congresses

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    Comparison of 3G-LTE DL scheduling strategies  Open access

     Ruiz Boque, Silvia; Haro, Eva; González González, David; Garcia Lozano, Mario; Olmos Bonafé, Juan José
    European Meeting COST 2100. Pervasive Mobile & Ambient Wireless Communications
    Presentation's date: 2009-05-18
    Presentation of work at congresses

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    Exponential effective SIR link performance model for LTE downlink  Open access

     Olmos Bonafé, Juan José; Serra, Albert; Ruiz Boque, Silvia; Garcia Lozano, Mario; González González, David
    European Meeting COST 2100. Pervasive Mobile & Ambient Wireless Communications
    Presentation's date: 2009-05-18
    Presentation of work at congresses

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    System Level Evaluation of LTE Networks with Semidistributed Intercell Interference Coordination  Open access

     González González, David; Ruiz Boque, Silvia; Garcia Lozano, Mario; Olmos Bonafé, Juan José; Serra, Albert
    IEEE International Symposium on Personal, Indoor, and Mobile Radio Communications
    Presentation's date: 2009-09-16
    Presentation of work at congresses

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    3GPP LTE is the evolution of UMTS which will make possible to deliver high quality multimedia services with an improved user experience. Since Radio Resource Management (RRM) has been recognized as a key point to successfully accomplish this target, the performance evaluation of a multi-cell resource allocation scheme applied to LTE downlink (DL) is presented in this paper. A semi-distributed RRM framework is discussed and evaluated from a system level viewpoint. Detailed link level simulations have also been carried out to properly back up the results.

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    Link level simulator for LTE downlink  Open access

     Olmos Bonafé, Juan José; Serra, Albert; Ruiz Boque, Silvia; Garcia Lozano, Mario; González González, David
    7th European Meeting COST-2100. Pervasive Mobile & Ambient Wireless Communications
    Presentation's date: 2009-02-16
    Presentation of work at congresses

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    3GPP LTE is the evolution of UMTS which will make possible to deliver next generation high quality multimedia services according to the users’ expectations. The flexibility of the downlink OFDM radio interface with Adaptive Modulation and Coding (AMC), MIMO and HARQ plays a crucial role in achieving the low latency and high spectral efficiency promised by the new radio access standard. This paper presents a link level simulator for LTE downlink whose main purpose is to generate suitable look-up tables to interface with a system level simulator. The obtained results include curves of mean link level throughput for different AMC formats and MIMO configurations. The methodology for training the Exponential Effective SINR model is also described with an example.

  • INGENIERIA Y OPTIMIZACION DE RED CELULAR EN LONG TERM EVOLUTION DE 3GPP

     Ruiz Boque, Silvia; Garcia Lozano, Mario; Alonso Zárate, Luis Gonzaga; Kartsakli, Elli; González González, David; Lema Rosas, Maria Angel; Olmos Bonafé, Juan José
    Participation in a competitive project

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    Link and system level simulation of downlink LTE  Open access

     González González, David; Ruiz Boque, Silvia; Olmos Bonafé, Juan José; Garcia Lozano, Mario; Serra, Albert
    European Meeting COST 2100. Pervasive Mobile & Ambient Wireless Communications
    Presentation's date: 2009-02-16
    Presentation of work at congresses

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    3GPP LTE is the evolution of the UMTS which will make possible to deliver next generation high quality multimedia services according to the users’ expectations. Since Radio Resource Management (RRM) has been recognized as a key point to successfully accomplish this target, the performance evaluation of a multi-cell resource allocation scheme applied to LTE downlink (DL) is presented in this paper. A semi-distributed and a fully-distributed RRM framework are compared on the basis of the obtained system throughput. Detailed link level simulations have also been carried out to properly back up the system level results.

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    Performance of DVB-T2 improvements over low doppler mobile channels  Open access

     Ruiz Boque, Silvia; López Arranz, Carlos; Enrique Herrero, Carlos; Alonso Zárate, Luis Gonzaga; Olmos Bonafé, Juan José; Garcia Lozano, Mario; Minerva, Flaminio
    European Meeting COST 2100. Pervasive Mobile & Ambient Wireless Communications
    Presentation's date: 2008-02-06
    Presentation of work at congresses

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    This paper addresses the simulation and the detailed analysis of some performance indicators and graphics of the changes in channel coding and modulation envisaged for DVB-T2. Results are given not only for ideal (Gaussian) or static (F1/P1) channels, but also for classical mobile channels (TU6) for low Doppler frequency (around 10 Hz). Finally the effects of implementing a channel (pilot) estimator (and interpolator) in both time and frequency domains have been analyzed and compared with one domain estimators (and interpolators).

  • Performance analysis of transport and radio load balancing strategies for BS assignment in mobile access networks

     Novillo, F; Galeana Zapién, Hiram; Ferrús Ferré, Ramon; Olmos Bonafé, Juan José
    2008 IEEE 19th International Symposium on Personal, Indoor and Mobile Radio Communications
    Presentation of work at congresses

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  • A base station assignment strategy for radio access networks with backhaul constraints

     Galeana Zapién, Hiram; Novillo Parales, Francisco Vicente; Ferrús Ferré, Ramon; Olmos Bonafé, Juan José
    ICT Mobile and Wireless Communications Summit (ICT-MobileSummit 2008)
    Presentation's date: 2008-06-12
    Presentation of work at congresses

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  • Comparison of transport capacity requirements in 3GPP R99 and HSDPA IP-based radio access networks

     Galeana Zapién, Hiram; Ferrús Ferré, Ramon; Olmos Bonafé, Juan José
    Annual IEEE International Symposium on Personal, Indoor and Mobile Radio Communications
    Presentation of work at congresses

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  • A functional end-to-end QoS architecture enabling radio and IP transport Coordination

     Olmos Bonafé, Juan José; Ferrús Ferré, Ramon; Sallent Roig, Jose Oriol; Pérez Romero, Jordi; Casadevall Palacio, Fernando-jose
    IEEE Wireless Communications & Networking Conference
    Presentation of work at congresses

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