@article {3113, title = {Application Layer Forward Error Correction for Multicast Streaming over LTE Networks}, journal = {International Journal of Communication Systems, Wiley InterScience}, volume = {26}, year = {2013}, pages = {1459-1574}, abstract = {

The next step beyond third generation (3G) mobile networks is the Third Generation Partnership Project (3GPP) standard, named Long Term Evolution (LTE). A key feature of LTE is the enhancement of Multimedia Broadcast/Multicast Services (MBMS), where the same content is transmitted to multiple users located in a specific service area. To support efficient download and streaming delivery, 3GPP included an application layer Forward Error Correction (AL-FEC) technique based on the systematic fountain Raptor code, in the MBMS standard. In order to achieve protection against packet losses, Raptor codes introduce redundant packets to the transmission, i.e., the FEC overhead. In this work, we investigate the application of AL-FEC over MBMS streaming services. We consider the benefits of AL-FEC for a continuous multimedia stream transmission to multiple users and we examine how the amount of FEC redundancy can be adjusted under different packet loss conditions. For this purpose, we present a variety of realistic simulation scenarios for the application of AL-FEC and furthermore we provide an in-depth analysis of Raptor codes performance introducing valuable suggestions to achieve efficient use of Raptor codes.

}, keywords = {FEC, LTE, MBMS}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Nikos Kanakis} } @article {3105, title = {Modulation and coding scheme selection in multimedia broadcast over a single frequency network-enabled long-term evolution networks}, journal = {International Journal of Communication Systems, Wiley InterScience}, volume = {25}, year = {2013}, pages = {1603-1619}, abstract = {

Long term evolution constitutes the next generation cellular network beyond 3G that is designed to support the explosion in demand for bandwidth-hungry multimedia services in wireless networks by providing an extremely high performance radio access technology. To support multimedia broadcast/multicast services (MBMS), long term evolution offers the functionality to transmit MBMS over a single frequency network, where a time-synchronized common waveform is transmitted from multiple cells for a given duration. This enables over-the-air combining, thus significantly improving the spectral efficiency (SE) compared with conventional MBMS operations. In MBMS over a single frequency network transmissions, the achieved SE is mainly determined by the modulation and coding scheme selected. This study proposes and evaluates four approaches for the selection of the modulation and coding scheme. Each approach corresponds to different users? distribution and multimedia traffic conditions. On the basis of SE measurements, we determine the approach that either maximizes or achieves a target SE for the corresponding users? distribution and traffic conditions. Copyright {\textcopyright} 2011 John Wiley \& Sons, Ltd.

}, keywords = {LTE, MBSFN, MCS}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and George Tsichritzis} } @article {3109, title = {Cost Optimization of MBSFN and PTM Transmissions for Reliable Multicasting in LTE Networks}, journal = {Wireless Networks, Springer Verlang}, year = {2012}, pages = {277-293}, abstract = {Long Term Evolution (LTE) systems have been specified and designed to accommodate small, high performance, power-efficient, end-user devices. The evolved Multimedia Broadcast/Multicast Service (e-MBMS) feature is introduced by the 3rd Generation Partnership Project (3GPP) as a complement to the existing MBMS service in order to accommodate multicast groups that are interested in receiving the same data. MBMS service is provided by MBMS over a Single Frequency Network (MBSFN) and/or Point-To-Multipoint (PTM) transmission methods. One of the challenges of MBMS is the complete error recovery of the transmitted files, a matter of great importance since the distribution of binary data must result in 100\% error-free download. To fulfill this tight requirement, Forward Error Correction (FEC) mechanism has been proposed by 3GPP. In this work, we investigate the reliable multicasting by introducing a transmission method that combines the advantages of MBSFN and PTM transmission methods. We compare several FEC-based file recovery methods and evaluate them against various network parameters in a realistic simulation environment. The comparison is based on a cost-oriented analysis of MBMS service that takes into account the transmission cost over all the interfaces and nodes of the LTE architecture. The simulation results are performed with the aid of a new simulation tool and show that the performance of the file repair schemes depend on the network configuration. KEYWORDS: multimedia multicasting; cellular networks; forward error correction; reliability; single frequency network; optimization; point to multipoint;}, keywords = {Cost analysis, LTE, MBSFN}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and Konstantinos Asimakis and Georgia Tseliou} } @conference {3000, title = {Enhaning Reliable Mobile Multicasting with RaptorQ FEC}, booktitle = {17th IEEE Symposium on Computers andCommunication (ISCC), Cappadocia, Turkey}, year = {2012}, month = {1-4 July}, pages = {82-87}, abstract = {A crucial point on the successful deployment of multicast services is the enhanced reliability by means of advanced error control schemes. To this direction Third Generation Partnership Project (3GPP) has standardized exclusively for Multimedia Broadcast/Multicast Services (MBMS) the use of a Forward Error Correction (FEC) mechanism on the application layer based on Raptor codes. Since the standardized systematic, fountain Raptor code is now considered obsolete, the emergence of a new variant of Raptor codes, named RaptorQ, provides enhanced capabilities for mobile multicast services. In this paper, we provide a performance comparison of the standardized Raptor Application Layer FEC (AL-FEC) scheme with the very promising RaptorQ FEC code. We examine the enhancements that RaptorQ introduces on the AL-FEC protection robustness, providing a thorough performance analysis in comparison with the current Raptor FEC scheme. Furthermore, in order to verify the improved performance of RaptorQ, we provide several simulation results utilizing the ns-3 environment, considering the application of both the examined AL-FEC schemes over multicast services for next generation mobile networks.}, keywords = {FEC, LTE, MBMS}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Nikos Kanakis} } @conference {2999, title = {Evaluating RaptorQ FEC over 3GPP Multicast Services}, booktitle = {The 8th International Wireless Communications \& Mobile Computing Conference (IWCMC 2012), Limassol, Cyprus}, year = {2012}, month = {August 27-31}, pages = {257 - 262}, abstract = {Third Generation Partnership Project (3GPP) introduced Multimedia Broadcast/Multicast Services (MBMS), in order to efficiently deliver the same content to multiple users over mobile cellular networks. To enhance the download and streaming delivery robustness against packet losses, 3GPP proposes the use of Forward Error Correction (FEC) on the application layer. The Application Layer FEC (AL-FEC) scheme that 3GPP standardized is based on the systematic, fountain Raptor code. In this work, in response to the emergence of an enhanced FEC scheme, we provide a performance evaluation of the existing standardized AL-FEC scheme with the newly introduced RaptorQ code. Introducing a variety of simulation experiments, we analyze the performance behavior of each AL-FEC scheme considering several FEC encoding parameters. Furthermore, we try to verify the improvements that have emerged in AL-FEC providing enhanced capabilities in multicast services over next generation mobile networks.}, keywords = {FEC, LTE, MBMS}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Nikos Kanakis} } @conference {3010, title = {Genetic Optimization for Spectral Efficient Multicasting in LTE Systems}, booktitle = {Fifth IFIP Wireless and Mobile Networking Conference, Bratislava, Slovakia}, year = {2012}, month = {19-21 September}, pages = {54-59}, abstract = {

Past research has proposed the usage of assisting cells with Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN) to increase the Spectral Efficiency (SE) of LTE. In this paper we propose and investigate a method for optimizing the power consumption of the network while retaining an acceptable SE for most users. We design an algorithm that makes use of genetic optimization and analytical estimation of the SE. The algorithm is implemented in a novel simulation tool that allows experimentation over various user distributions and LTE deployments similar to the real-world ones. This simulation tool estimates the SE of each user and is able to optimize the network deployment by adjusting the individual transmission power levels for each cell.

}, keywords = {LTE, MBMS, MBSFN}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Konstantinos Asimakis} } @conference {2997, title = {Interference Management in LTE Femtocell Systems Using an Adaptive Frequency Reuse Scheme}, booktitle = {Wireless Telecommunications Symposium (WTS 2012), London, UK}, year = {2012}, month = {18-20 April}, abstract = {Long Term Evolution (LTE) has developed a new technology in order to enhance indoor coverage. This new technology is called femtocells and is achieved with the use of access points installed by home users. However, interference problem between the femtocell and the macrocell decreases the system{\textquoteright}s capacity and as a result users{\textquoteright} throughput. In this paper we study the interference mitigation techniques in femtocell/macrocell networks and we propose a frequency reuse mechanism that leads to increased overall system performance. In particular, the mechanism aims to maximize throughput via a variety of combinations between inner cell radius and frequency allocation to the macrocell. Additionally, a position minded frequency allocation to the femtocells targets to further optimize the total throughput of the cell.}, keywords = {Femtocell, FFR, LTE}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Georgios Kavourgias} } @inbook {3145, title = {Multimedia Broadcasting in LTE Networks}, booktitle = {Access Environments and Quality of Service Provisioning: Solutions and Applications}, year = {2012}, pages = {269-289}, publisher = {IGI Global}, organization = {IGI Global}, chapter = {11}, abstract = {

Long Term Evolution (LTE) constitutes the latest step before the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile communications. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers the functionality to transmit MBMS over Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted from multiple cells for a given duration. In MBSFN transmissions, the achieved Spectral Efficiency (SE) is mainly determined by the Modulation and Coding Scheme (MCS) selected. This study proposes and evaluates four approaches for the selection of the MCS that will be utilized for the transmission of the MBSFN data. The evaluation of the approaches is performed for different users? distribution and from SE perspective. Based on the SE measurement, we determine the approach that either maximizes or achieves a target SE for the corresponding users? distribution.

}, keywords = {LTE, MBMS}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and George Tsichritzis} } @conference {2995, title = {Optimization of Fractional Frequency Reuse in Long Term Evolution Networks}, booktitle = {2012 IEEE Wireless Communications and Networking Conference (WCNC 2012), Paris, France}, year = {2012}, month = {1-4 April}, pages = {1875-1879}, abstract = {In cellular systems, Fractional Frequency Reuse (FFR) partitions each cell into two regions; inner region and outer region and allocates different frequency band to each region. Since the users at the inner region are less exposed to inter-cell interference, the frequency resources in each inner region can be universally used. Based on this frequency band allocation, FFR may reduce channel interference and offer large system capacity. This paper proposes a mechanism that selects the optimal FFR scheme based on the user throughput and user satisfaction. In detail, the mechanism selects the optimal size of the inner and outer region for each cell as well as the optimal frequency allocation between these regions that either maximizes the mean user throughput or the user satisfaction. The mechanism is evaluated through several simulation scenarios.}, keywords = {FFR, LTE}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Georgia Tseliou and Dimitrios Bilios} } @article {3104, title = {Performance Evaluation of LTE for MBSFN Transmissions}, journal = {Wireless Networks, Springer Verlang}, volume = {18}, year = {2012}, pages = {227-240}, abstract = {

Long Term Evolution (LTE) is the most promised latest step towards the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile communications with main target the support of the so-called {\textquotedblleft}Mobile Broadband{\textquotedblright}. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers the possibility to transmit Multimedia Broadcast multicast service over a Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted from multiple cells for a given duration. In this manuscript we analytically present the MBSFN delivery method and evaluate its performance. The critical parameters of primary interest for the evaluation of the scheme are the packet delivery cost and its scalability. To this direction, a telecommunication cost analysis of the MBMS service is presented based on the transmission cost over the air interface, as well as the costs of all interfaces and nodes of the MBSFN architecture. Based on this cost analysis we determine the ideal number of cells that should participate in the MBSFN transmission in order to improve the overall MBSFN performance. Since the performance of the MBSFN scheme mainly depends on the configuration of the LTE network that is under investigation, we consider different network topologies, MBSFN deployments and user distributions.

}, keywords = {LTE, MBSFN}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos and George Tsichritzis} } @conference {3008, title = {A Performance Study of Fractional Frequency Reuse in OFDMA Networks}, booktitle = {Fifth IFIP Wireless and Mobile Networking Conference, Bratislava, Slovakia}, year = {2012}, month = {19-21 September}, pages = {38 - 43}, abstract = {

Long Term Evolution (LTE) technology is considered as the most possible candidate for next generation mobile communications. LTE networks offer high capacity and are specified and designed to accommodate small, high performance, power-efficient end-user devices. One limiting factor that influences LTE performance is the interference from neighbor cells, the so called Inter-Cell Interference (ICI). Fractional Frequency Reuse (FFR) has been proposed as a technique to overcome this problem, since it can efficiently utilize the available frequency spectrum. This paper analyzes the FFR scheme and proposes a dynamic FFR mechanism that selects the optimal frequency allocation based on the cell total throughput and user satisfaction. In detail, the mechanism divides the cell into two regions (inner and outer) and selects the optimal size as well as the optimal frequency allocation between these regions with main target to maximize the overall throughput and user satisfaction. The mechanism is evaluated through several simulation scenariosthat incorporate users? mobility.

}, keywords = {FFR, LTE}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Georgia Tseliou and Dimitrios Bilios} } @conference {3007, title = {A Simulation Framework for LTE-A Systems with Femtocell Overlays}, booktitle = {ACM PM2HW2N 2012 Workshop, Paphos, Cyprus}, year = {2012}, month = {21 - 25 October}, pages = {85 - 90}, abstract = {The use of femtocells is an efficient way to improve cover- age and quality of service while on the other side the deployment cost for the service provider is kept in extremely low level. Long Term Evolution Advanced (LTE-A) systems with femtocell overlays aim to provide better indoor voice and data coverage and to increase network capacity. One of the major technical challenges that femtocell networks are facing nowadays, is the cross-tier interference, i.e., the interference between the femto base stations and the macrocell infrastructure. To this direction, we have designed and implemented a framework that simulates femtocell overlays integrated over LTE-A macrocellular systems. This framework focuses on the impact of cross-tier interference and furthermore is able to estimate the throughput at every point of integrated femtocell/macrocell LTE-A networks. In this paper, we present the design and implementation of this simulation framework and we provide significant experimental results obtained with the aid of this system.}, keywords = {Femtocell, LTE}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Konstantinos Kontodimas} } @conference {2990, title = {AL-FEC for Streaming Services over LTE Systems}, booktitle = {14th International Symposiumon Wireless Personal Multimedia Communications, Brest, France}, year = {2011}, month = {October 3 - 6}, pages = {284-288}, abstract = {

The Third Generation Partnership Project (3GPP), recently introduced the evolution of the third generation (3G) cellular networks, the Long Term Evolution (LTE) telecommunication system. A key aspect of LTE specifications is the enhancement of Multimedia Broadcast/Multicast Services (MBMS), where the same content is transmitted to multiple users located in a specific service area. A significant point of the demanding multimedia services is the enhancement of the robustness against packet losses. To this direction, in order to support the efficient point-to-multipoint download and streaming delivery, 3GPP has included an Application Layer Forward Error Correction (AL-FEC) scheme in the MBMS standard. The standardized AL-FEC scheme is based on the systematic, fountain Raptor codes. In this paper, we investigate the application of AL-FEC over the MBMS streaming delivery method. We consider the benefits of AL-FEC for a seamless multimedia streaming transmission to multiple mobile users and we examine how the amount of FEC overhead can be adjusted under different packet loss conditions. For this purpose, we present a variety of realistic simulation scenarios for the performance evaluation of FEC considering several network and FEC encoding parameters. Furthermore, we provide suggestions in order to achieve efficient use of Raptor codes over LTE MBMS streaming services.

}, keywords = {FEC, LTE, MBMS}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Nikos Kanakis} } @conference {2984, title = {Combining MBSFN and PTM Transmissions Schemes for Resource Efficiency in LTE Networks}, booktitle = {9th International Conference on Wired/Wireless Internet Communications, Vilanova I la Geltru, Barcelona, Spain, June 15 - 17, 2011}, year = {2011}, pages = { 56 - 67}, abstract = {Long Term Evolution (LTE) systems allow the transmission of rich multimedia services by utilizing the Multimedia Broadcast/Multicast Service (MBMS) over a Single Frequency Network (MBSFN). During MBSFN transmission a time-synchronized common waveform is transmitted from multiple cells. The 3rd Generation Partnership Project (3GPP) has specified that Point-to-Multipoint (PTM) transmission can be used in combination with MBSFN to provide MBMS-based services. In this paper we evaluate the combined transmission scheme in terms of Resource Efficiency (RE). The evaluation is performed through simulation experiments for various user distributions and LTE network configurations. The experiments are conducted with the aid of a proposed algorithm, which estimates the Spectral Efficiency (SE) of each cell and the RE of the network, and is also able to formulate the optimal network deployment that maximizes the network?s RE. For each of the examined scenarios, we present the most efficient solution (in terms of RE) selected by our algorithm and we compare it with other transmission schemes.}, keywords = {LTE, MBMS, MBSFN}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and Konstantinos Asimakis} } @inbook {3144, title = {Forward Error Correction for Reliable e-MBMS Transmissions in LTE Networks}, booktitle = {Cellurar Networks}, year = {2011}, pages = { 353 - 374}, publisher = {InTech}, organization = {InTech}, keywords = {FEC, LTE, MBMS}, author = {Christos Bouras and Andreas Papazois and Vasileios Kokkinos and Georgia Tseliou} } @conference {2991, title = {Interference Behavior of Integrated Femto and Macrocell Environments}, booktitle = {IFIP Wireless Days 2011, Niagara Falls, Ontario, Canada}, year = {2011}, month = {October 10 \&$\#$8211; 12}, abstract = {Abstract{\textemdash}Femtocells are data access points installed by the subscribers to provide better indoor voice and data coverage and to increase system capacity. The integrated femtocell/macrocell networks offer an efficient way to increase access capacity by improving coverage and quality of service while on the other side the deployment cost for the service provider is kept in extremely low levels. One of the major technical challenges that femtocell networks are facing is their interference behavior when they are placed within macrocells. The study presented in this paper focuses on the impact of integrating femtocells in macrocell networks in terms of adjacent cell interference that the macrocell environment adds to users served by a femto base station and vice versa. To this direction, we have designed and implemented a simulation testbed that estimates the cross-tier interference and the throughput in every point of an integrated femtocell/macrocell Long Term Evolution-Advanced (LTE-A) network.}, keywords = {Femtocell, LTE}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and Konstantinos Kontodimas} } @conference {2982, title = {Optimizing the Combination of MBSFN and PTM Transmissions in LTE Systems}, booktitle = {Tenth Annual Wireless Telecommunications Symposium (WTS 2011), New York, USA}, year = {2011}, month = {April 13-15}, abstract = {The 3rd Generation Partnership Project (3GPP) has introduced the evolved Multimedia Broadcast/Multicast Service (e-MBMS) feature for cellular systems as an evolution to the existing MBMS service. To support e-MBMS in Long Term Evolution (LTE) systems, 3GPP recommends the use of Point-to- Multipoint (PTM) transmissions and MBMS over a Single Frequency Network (MBSFN). MBSFN is a new feature where a time-synchronized common waveform is transmitted from multiple cells. In this paper we investigate the provision of MBMS service over a combination of MBSFN and PTM transmission methods. A cost analysis of the MBMS service is presented based on the transmission cost over all the interfaces and nodes of the LTE architecture. We evaluate the performance of this transmission scheme from telecommunication cost perspective and we compare it with other transmission schemes. The performance evaluation has been performed with the aid of a new simulation tool that estimates the cost for the MBMS provision under different network topologies, MBSFN deployments and user distributions.}, keywords = {LTE, MBMS, MBSFN}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and Georgia Tseliou} } @conference {2983, title = {Reliable Multicasting over LTE: A Performance Study}, booktitle = {16th IEEE Symposioum on Computers and Communications (ISCC 2011), Kerkyra, Greece}, year = {2011}, month = {June 28 - July 1}, pages = { 603 - 608}, abstract = {With the booming of multimedia services, the 3rd Generation Partnership Project (3GPP) has introduced the evolved Multimedia Multicast/Broadcast Service (e-MBMS) feature for LTE systems. The main objective of MBMS is to introduce real broadcast distribution capabilities into cellular systems. This purposed 3GPP to introduce the MBMS over a Single Frequency Network (MBSFN) operation. In this work we investigate the provision of MBMS service over a combination of MBSFN and PTM transmission schemes. We focus on the file repair procedure, because the distribution of binary data via MBMS must result in 100\% error-free downloaded files. In order to achieve this goal, MBMS offers a Forward Error Correction (FEC) mechanism. Our simulation results show that there are some file repair schemes that achieve better performance as far as different network configurations are concerned. Furthermore, we compare all the file recovery methods and evaluate them against various network parameters in a realistic simulation environment.}, keywords = {FEC, LTE, MBMS, MBSFN}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and Konstantinos Asimakis and Georgia Tseliou} } @conference {2981, title = {Adopting FEC for Reliable Multicasting over LTE Networks}, booktitle = {13th ACM International Conference on Modeling Analysis and Simulation of Wireless and Mobile Systems, Bodrum, Turkey}, year = {2010}, month = {October 17 - 21}, pages = { 307 - 310}, abstract = {The key feature for the provision of Multimedia Broadcast/Multicast Services (MBMS) in Long Term Evolution (LTE) networks is the Multimedia Broadcast over a Single Frequency Network (MBSFN). On the other hand, the use of Forward Error Correction (FEC) in mobile multicast transmission has significant advantages and the 3rd Generation Partnership Project (3GPP) has adopted the application layer FEC in the MBMS standard. In this paper, we investigate the impact of the application layer FEC over the MBSFN delivery method.}, keywords = {FEC, LTE, MBMS}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and George Tsichritzis} } @conference {2964, title = {Adopting forward error correction for multicasting over cellurar networks}, booktitle = {European Wireless 2010, Lucca, Italy}, year = {2010}, month = {12 - 15 April }, pages = {307-310}, abstract = {

FEC is an error control method that can be used to augment or replace other methods for reliable data transmission. Such schemes inevitably add a constant overhead in the transmitted data. However, they are so simple as to meet a prime objective for UMTS multicast services, that is scalability to applications with thousands of receivers. This is the reason that 3GPP recommends the use of FEC for MBMS framework. In this paper, we use a probabilistic model for the multicast user distribution in the network and we define a scheme for multicast data delivery that combines FEC with traditional ARQ. It is important that our analysis is compliant with the 3GPP specifications and considers the latest advances in mobile networks. In this framework we investigate the impact of FEC use, we examine whether it is beneficial, how the optimal FEC code dimensioning varies based on the network conditions, which parameters affect the optimal FEC code selection, and how they do it.

}, keywords = {FEC, LTE, MBMS, MBSFN}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois} } @conference {2971, title = {Communication Cost Analysis of MBSFN in LTE}, booktitle = {The 21st IEEE Symposium on Personal, Indoor and Mobile Radio Communications (PIMRC 2010), Istanbul, Turkey}, year = {2010}, month = {September 26 - 30}, pages = { 1366-1371}, abstract = {Long Term Evolution (LTE) is the latest step towards the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile communications. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers the possibility to transmit Multimedia Broadcast multicast service over a Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted from multiple cells for a given duration. In this paper we analytically present the MBSFN delivery method and evaluate its performance. The critical parameters of primary interest for the evaluation of the scheme are the packet delivery cost and its scalability. To this direction, a telecommunication cost analysis of the MBMS service is presented based on the transmission cost over the air interface, as well as the costs of all interfaces and nodes of the MBSFN architecture. Since the performance of the MBSFN scheme mainly depends on the configuration of the LTE network that is under investigation, we consider different network topologies, MBSFN deployments and user distributions.}, keywords = {Cost analysis, LTE, MBSFN}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos and George Tsichritzis} } @conference {2978, title = {Efficient MCS Selection for MBSFN Transmissions over LTE Networks}, booktitle = {IFIP Wireless Days 2010, Venice, Italy}, year = {2010}, month = {October 20 - 22}, abstract = {Long Term Evolution (LTE), the next-generation network beyond 3G, is designed to support the explosion in demand for bandwidth-hungry multimedia services that are already experienced in wired networks. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers functionality to transmit MBMS over a Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted from multiple cells for a given duration. This significantly improves the Spectral Efficiency (SE) compared to conventional MBMS operation. The achieved SE is mainly determined by the Modulation and Coding Scheme (MCS) utilized by the LTE physical layer. In this paper we propose and evaluate four approaches for the selection of the MCS that will be utilized for the transmission of the MBSFN data. The evaluation of the approaches is performed for different users? distribution and from SE perspective. Based on the SE measurement, we determine the most suitable approach for the corresponding users? distribution.}, keywords = {LTE, MBMS, MBSFN, MCS}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and George Tsichritzis} } @inbook {3138, title = {Efficient Power Allocation in E-MBMS Enabled 4G Networks}, booktitle = {Wireless Network Traffic and Quality of Service Support: Trends and Standards}, year = {2010}, pages = { 458 - 488}, publisher = {IGI Global}, organization = {IGI Global}, chapter = {18}, abstract = {

The plethora of mobile multimedia services that are expected to face high penetration, poses the need for the deployment of a resource economic scheme in Long Term Evolution (LTE) networks. To this direction, the Evolved - Multimedia Broadcast / Multicast Service (E- MBMS) is envisaged to play an instrumental role for LTE proliferation and set the basis for a successful 4th Generation (4G) standardization process. One of the most critical aspects of E- MBMS performance is the selection of the most efficient radio bearer, in terms of power consumption. This chapter presents the prevailing radio bearer selection mechanisms and examines their performance in terms of power consumption. Furthermore, it discusses problems regarding the high power requirements for the realization of E-MBMS and evaluates the proposed techniques/solutions. Finally, this chapter presents a novel mechanism for efficient power control during E-MBMS transmissions that conforms to LTE requirements for simultaneous provision of multiple multimedia sessions.

}, keywords = {LTE, MBMS, Power Control}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos} } @conference {2979, title = {Enhancing FEC Application in LTE Cellular Networks}, booktitle = {IFIP Wireless Days 2010, Venice, Italy}, year = {2010}, month = {October 20 - 22}, abstract = {3rd Generation Partnership Project?s (3GPP) Long Term Evolution (LTE) is focused on enhancing the Universal Terrestrial Radio Access (UTRA). Evolved-Multimedia Broadcast and Multicast Service (e-MBMS) uses Multimedia Broadcast over a Single Frequency Network (MBSFN) operation in order to improve its performance. In MBSFN operation, data are transmitted simultaneously over the air from multiple tightly time-synchronized cells. Raptor codes have been standardized as the main application layer Forward Error Correction (FEC) method for e-MBMS due to the advanced error protection they offer and their overall performance. In this study, we investigate the application of FEC in MBSFN-enabled LTE cellular networks and we propose a new scheme that takes into account the properties of MBSFN in order to provide a more efficient operation of FEC during e-MBMS transmissions. The proposed scheme is compared with other file recovery methods and is evaluated against various network parameters in a realistic simulation environment.}, keywords = {FEC, LTE, MBMS, MBSFN}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and Georgia Tseliou} } @conference {2966, title = {The Impact of FEC on Mobile Multicast Power Control}, booktitle = {The Sixth Advanced International Conference on Telecommunications (AICT 2010), Barcelona, Spain}, year = {2010}, month = {May 9 - 15}, pages = {1-6}, abstract = {3GPP has standardized the use of forward error correction for the provision of reliable data transmission in the mobile multicast framework. In this paper we present a study of the impact of application layer forward error correction on power control during mobile multicast transmission. The evaluation is performed with the aid of a novel scheme that allows the simulation of FEC impact on both streaming delivery and download delivery over a multicast session. It is important that the proposed scheme incorporates the properties of an evolved mobile network, as they are determined by the 3GPP specifications.}, keywords = {FEC, LTE, MBMS, Power Control}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois} } @article {3089, title = {An Improved MBMS Power Counting Mechanism towards Long Term Evolution}, journal = {Telecommunication Systems Journal, Springer Verlang}, volume = {43}, year = {2010}, pages = { 109 - 119}, abstract = {

One of the key objectives of beyond 3rd generation mobile networks is the realization of enhanced end-user experience through the provision of rich multimedia services. Multimedia Broadcast/Multicast Services (MBMS) framework epitomizes the increasing popularity of such applications and is envisaged to play an instrumental role for the Long Term Evolution (LTE) proliferation in mobile market. For exploiting resource efficiency, MBMS specifications consider the Counting Mechanism which decides whether it is more efficient to deliver MBMS multicast traffic over Point-to-Point (PTP) or Point-to-Multipoint (PTM) bearers. However, the necessity to further improve MBMS resource efficiency and integrate new technologies in the frame of LTE stresses the need for an advanced Counting Mechanism. In this work we propose a novel Power Counting Mechanism for efficient selection of MBMS bearers. The proposed mechanism optimally utilizes power resources and exploits broadband characteristics and performance enhancements emerged from Multiple Input Multiple Output (MIMO) antennas used in LTE networks.

}, keywords = {LTE, MBMS, Power Control}, author = {Christos Bouras and Antonios Alexiou and Evangelos Rekkas} } @inbook {3139, title = {Radio Resource Management for E-MBMS Transmissions towards LTE}, booktitle = {Evolved Cellular Network Planning and Optimization for UMTS and LTE}, year = {2010}, pages = { 331 - 360}, publisher = {Auerbach Publications, CRC Press, Taylor and Francis Group}, organization = {Auerbach Publications, CRC Press, Taylor and Francis Group}, chapter = {9}, abstract = {

Long Term Evolution (LTE) constitutes a key standard that paves the way for the future mobile broadband landscape envisioned by 4th Generation (4G) wireless networks. Actu- ally, LTE addresses the emerging trend for the mass provision of rich multimedia services, such as Mobile TV, in a more power and spectral e{\textpm}cient way than its predecessors. To this direction, the Evolved - Multimedia Broadcast/Multicast Service (E-MBMS) frame- work is envisaged to play an instrumental role for the LTE proliferation in mobile. E-MBMS constitutes the evolutionary successor of MBMS, which was introduced in the Release 6 of Universal Mobile Telecommunication System (UMTS). MBMS is designed in order to deliver multimedia data from a single source entity to multiple destinations. However, downlink ca- pacity in such networks is limited by base station transmission power. As an aftermath, in MBMS e{\textpm}cient power allocation techniques should be implemented so as to ensure the mass provision of multimedia applications to mobile users. This chapter presents several techniques and mechanisms used today for MBMS power optimization in next generation cellular networks.

}, keywords = {LTE, MBMS, Power Control}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos} } @conference {2975, title = {Spectral Efficiency Performance of MBSFN-enabled LTE Networks}, booktitle = {6th IEEE International Conference on Wireless and Mobile Computing, Networking and Communication (WiMob 2010), Niagara Falls, Canada}, year = {2010}, month = {October 11 - 13}, pages = { 361 - 367}, abstract = {Long Term Evolution (LTE) constitutes the latest step before the 4th generation (4G) of radio technologies designed to increase the capacity and speed of mobile communications. To support Multimedia Broadcast/Multicast Services (MBMS), LTE offers the possibility to transmit Multimedia Broadcast multicast service over a Single Frequency Network (MBSFN), where a time-synchronized common waveform is transmitted from multiple cells for a given duration. This enables over-the-air combining, thus improving the Signal to Interference plus Noise Ratio (SINR) and spectral efficiency (SE) significantly compared to conventional MBMS operation. In this paper, we analytically calculate the SE performance achieved in a MBSFN area for a dynamically changing user topology and different modulation and coding schemes (MCS). Finally, based on the SE measurement, we determine the MCS scheme that either maximizes or achieves a target SE for the corresponding user distribution.}, keywords = {LTE, MBMS, MBSFN, MCS}, author = {Christos Bouras and Antonios Alexiou and Andreas Papazois and Vasileios Kokkinos and George Tsichritzis} } @conference {2957, title = {Efficient Assignment of Multiple E-MBMS Sessions toward LTE}, booktitle = {Second Joint IFIP Wireless and Mobile Networking Conference, Gdansk, Poland}, year = {2009}, month = {9 - 11 September}, pages = { 240 - 250}, abstract = {One of the major prerequisites for Long Term Evolution (LTE) networks is the mass provision of multimedia services to mobile users. To this end, Evolved - Multimedia Broadcast/Multicast Service (E-MBMS) is envisaged to play an instrumental role during LTE standardization process and ensure LTE?s proliferation in mobile market. E-MBMS targets at the economic delivery, in terms of power and spectral efficiency, of multimedia data from a single source entity to multiple destinations. This paper proposes a novel mechanism for efficient radio bearer selection during E-MBMS transmissions in LTE networks. The proposed mechanism is based on the concept of transport channels combination in any cell of the network. Most significantly, the mechanism manages to efficiently deliver multiple E-MBMS sessions. The performance of the proposed mechanism is evaluated and compared with several radio bearer selection mechanisms in order to highlight the enhancements that it provides.}, keywords = {LTE, MBMS}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos} } @conference {2950, title = {An Enhanced MBMS Power Control Mechanism towards Long Term Evolution}, booktitle = {Eighth Annual Wireless Telecommunications Symposium - WTS 2009, Prague, Czech Republic}, year = {2009}, month = {22 - 24 April}, abstract = {Long Term Evolution (LTE) promises the delivery of rich multimedia services in a more power and spectral efficient way than its predecessor Universal Mobile Telecommunication System (UMTS). To this direction, the newly introduced Enhanced - Multimedia Broadcast/Multicast Service (E-MBMS) framework is envisaged to play a fundamental role during the LTE standardization. E-MBMS constitutes the successor of MBMS which was introduced in the Release 6 of UMTS in order to deliver multimedia data from a single source entity to multiple destinations. This paper proposes a novel mechanism for efficient radio bearer selection during E-MBMS transmissions in LTE networks. The proposed mechanism is based on the concept of transport channels combination (pointto- point and/or point-to-multipoint radio bearers) in any cell/sector of the network in which multicast users are residing. The mechanism is evaluated through several realistic scenarios and is compared with several radio bearer selection mechanisms in order to highlight the enhancements that it provides.}, keywords = {LTE, MBMS, Power Control}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos} } @conference {2958, title = {An Enhanced Mechanism for Efficient Assignment of Multiple sessions towards LTE}, booktitle = {The 12th ACM Annual Conference on Modeling, Analysis and Simulation of Wireless Mobile Systems, Tenerife, The Canary Islands, Spain}, year = {2009}, month = {26 - 30 October}, pages = { 384 - 391}, abstract = {The provision of rich multimedia services, such as Mobile TV, is considered of key importance for the Long Term Evolution (LTE) proliferation in mobile market. To this direction, Evolved - Multimedia Broadcast/Multicast Service (E-MBMS) that targets at the efficient delivery of multimedia data from a single source entity to multiple destinations, is envisaged to play an instrumental role during LTE standardization process. However, both LTE and E-MBMS performance are limited by the base station?s transmission power. As an aftermath, efficient power allocation techniques should be implemented so as to ensure the mass provision of multimedia applications to mobile users. This paper proposes a novel mechanism for efficient radio bearer selection during E-MBMS transmissions in LTE networks. The proposed mechanism is based on the concept of transport channels combination in any cell of the network. Most significantly, the mechanism exploits the performance enhancements emerged from Multiple Input Multiple Output (MIMO) antennas used in LTE networks and manages to efficiently deliver multiple E-MBMS sessions. The proposed mechanism is thoroughly evaluated and compared with several radio bearer selection mechanisms existing in bibliography.}, keywords = {LTE, MBMS, Power Control, UMTS}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos} } @article {3091, title = {Evaluation of Different Power Saving Techniques for MBMS Services}, journal = {EURASIP Journal on Wireless Communications and Networking, Hindawi Publishing Corporation}, year = {2009}, abstract = {Over the last years we have witnessed an explosive growth of multimedia computing, wireless communication and applications. Following the rapid increase in penetration rate of broadband services, the Third Generation Partnership Project (3GPP) is currently standardizing the Evolved-Multimedia Broadcast/Multicast Service (E-MBMS) framework of Long Term Evolution (LTE), the successor ofUniversalMobile Telecommunications System (UMTS).MBMS constitutes a point-to-multipoint downlink bearer service that was designed to significantly decrease the required radio and wired link resources. However, several obstacles regarding the high-power requirements should be overcome for the realization of MBMS. Techniques, such as Macrodiversity Combining and Rate Splitting, could be utilized to reduce the power requirement of delivering multicast traffic toMBMS users. In this paper, we analytically present several power saving techniques and analyze their performance in terms of power consumption. We provide simulation results that reveal the amount of power that is saved and reinforce the need for the usage of such techniques.}, keywords = {LTE, MBMS, Power Control}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos} } @conference {2943, title = {Optimal MBMS Power Allocation Exploiting MIMO in LTE Networks}, booktitle = {2009 IEEE 69th Vehicular Technology Conference VTC2009 Spring, Barcelona, Spain}, year = {2009}, month = {26 - 29 April}, abstract = {In the frame of the Long Term Evolution (LTE) of mobile networks, the provision of rich multimedia services, such as Mobile TV, is considered of key importance for the LTE proliferation in mobile market. To this end, Multimedia Broadcast/Multicast Service (MBMS) is envisaged to play an instrumental role during LTE standardization process. MBMS was introduced in the Release 6 of Universal Mobile Telecommunication System (UMTS) in order to deliver multimedia data from a single source entity to multiple destinations. However, downlink capacity in such networks is limited by base station transmission power. As an aftermath, in MBMS efficient power allocation techniques should be implemented so as to ensure the mass provision of multimedia applications to mobile users. In this paper we propose a power control scheme for efficient selection of MBMS bearers. The proposed mechanism on the one hand manages to economically utilize power resources during MBMS transmissions, while on the other hand exploits the performance enhancements emerged from Multiple Input Multiple Output (MIMO) antennas used in LTE networks. Simulation results indicate that the proposed scheme results to significant power and capacity improvements.}, keywords = {LTE, MBMS, Power Control}, author = {Christos Bouras and Antonios Alexiou and Vasileios Kokkinos and Evangelos Rekkas} }