143 research outputs found

    Interference Coordination for E-MBMS Transmissions in LTE-Advanced

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    Interference coordination methods for Evolved-Multimedia Broadcast/Multicast Service (E-MBMS) in Long-Term Evolution Advanced (LTE-A) are presented. In addition, we consider signal space diversity based on Rotation Matrices (RM) known to provide good performance gains over uncorrelated Rayleigh fading channels. OFDM/OFDMA systems can make the use of RM very attractive both for single and multiple antenna transmissions. In this paper, OFDM/OFDMA signals based on LTE parameters are combined with RM, MIMO, Turbo, or LDPC codes. We have considered different types of receivers, namely, we used an MMSE (Minimum Mean Squared Error) equalizer and a Maximum Likelihood Soft Output criterion (MLSO). Frequency, signal, and space diversity gains are evaluated for different spatial channel models (SCM) based on ITU multipath propagation channels. Different adaptive frequency reuse and schedulers are considered to evaluate the E-MBMS spectral efficiency at the cell borders

    System Level Simulation of E-MBMS Transmissions in LTE-A

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    Interference coordination methods for EvolvedMultimedia Broadcast/Multicast Service (E-MBMS) in LongTerm Evolution Advanced (LTE-A) are presented. In this paper, OFDM/OFDMA signals based on LTE parameters are combined with Multipoint MIMO, Turbo codes and signal space diversity methods. Different interference coordination techniques, such as, Multipoint MIMO coordination, Fixed Relay stations, adaptive frequency reuse and schedulers are considered to evaluate the E-MBMS spectral efficiency at the cell borders. The system level coverage and throughput gains of Multipoint MIMO system with hierarchical constellations and Turbo-codes are simulated associated to the presence or not of fixed relays and measuring the maximum spectral efficiencies at cell borders of single cell point-to-multipoint or single frequency network topologies. The influence of the relay transmission power and cell radius in the performance of the previous cellular topologies is also evaluated

    Project Final Report – FREEDOM ICT-248891

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    This document is the final publishable summary report of the objective and work carried out within the European Project FREEDOM, ICT-248891.This document is the final publishable summary report of the objective and work carried out within the European Project FREEDOM, ICT-248891.Preprin

    V2X Meets NOMA: Non-Orthogonal Multiple Access for 5G Enabled Vehicular Networks

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    Benefited from the widely deployed infrastructure, the LTE network has recently been considered as a promising candidate to support the vehicle-to-everything (V2X) services. However, with a massive number of devices accessing the V2X network in the future, the conventional OFDM-based LTE network faces the congestion issues due to its low efficiency of orthogonal access, resulting in significant access delay and posing a great challenge especially to safety-critical applications. The non-orthogonal multiple access (NOMA) technique has been well recognized as an effective solution for the future 5G cellular networks to provide broadband communications and massive connectivity. In this article, we investigate the applicability of NOMA in supporting cellular V2X services to achieve low latency and high reliability. Starting with a basic V2X unicast system, a novel NOMA-based scheme is proposed to tackle the technical hurdles in designing high spectral efficient scheduling and resource allocation schemes in the ultra dense topology. We then extend it to a more general V2X broadcasting system. Other NOMA-based extended V2X applications and some open issues are also discussed.Comment: Accepted by IEEE Wireless Communications Magazin

    MBMS—IP Multicast/Broadcast in 3G Networks

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    In this article, the Multimedia Broadcast and Multicast Service (MBMS) as standardized in 3GPP is presented. With MBMS, multicast and broadcast capabilities are introduced into cellular networks. After an introduction into MBMS technology, MBMS radio bearer realizations are presented. Different MBMS bearer services like broadcast mode, enhanced broadcast mode and multicast mode are discussed. Streaming and download services over MBMS are presented and supported media codecs are listed. Service layer components as defined in Open Mobile Alliance (OMA) are introduced. For a Mobile TV use case capacity improvements achieved by MBMS are shown. Finally, evolution of MBMS as part of 3GPP standardization is presented

    Performance Evaluation of Scalable Multi-cell On-Demand Broadcast Protocols

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    As mobile data service becomes popular in today's mobile network, the data traffic burden irrevocably increases. LTE 4G, as the next-generation mobile technology, provides high data rates and improved spectral efficiency for data transmission. Currently in the mobile network, mobile data service solely relies on the point-to-point unicast transmission. In the ever-evolving 4G mobile network, mobile broadcast may serve as a supplemental means of pushing mobile data content from the data server to the mobile user devices. As part of the LTE 4G specifications, the mobile broadcast technology referred to as eMBMS is designed for supporting the mobile data service. From eMBMS, SFN broadcast transmission scheme allows data broadcasting to be synchronized in all cells of a defined core network area. LTE 4G also enables single-cell broadcast scheme in which data broadcasting is taking place independently in every cell. In this thesis, besides SFN or single-cell broadcast transmission, a hybrid broadcast transmission scheme in which SFN and single-cell broadcast transmission are used interchangeably in the same network based on the network conditions is proposed. For on-demand data service, the pull-based scheduling protocols from previous work are originally designed to work in a single-cell case scenario. With slight modifications, the batching/cbd protocol can be adapted for multi-cell data service. A new combined scheduling protocol, that is cyclic/cd,fft protocol, is devised as the second candidate for multi-cell data transmission scheduling. Based on the three broadcast transmission schemes and the two broadcast scheduling protocols, six mobile broadcast protocols are proposed. The mobile broadcast models, which correspond to the six mobile broadcast protocols, are evaluated by analysis and simulation experiment. By analysis, the cost equations are derived for calculating average server bandwidth, average client delay and maximum client delay of the mobile broadcast models. In the experiment, the input parameters of broadcast test models are assessed one at a time. The experimental results show that the hybrid broadcast transmission together with cyclic/cd,fft protocol would provide the best server bandwidth performance and the SFN broadcast transmission together with batching/cbd protocol provides the best average delay performance
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