Tài liệu miễn phí Kĩ thuật Viễn thông
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Capacity maximisation for hybrid digital-to-analog beamforming mm-Wave systems
Millimetre waves (mm-Waves) with massive multiple input and multiple output (MIMO) have the potential to fulfill fifth generation (5G) traffic demands. In this paper, a hybrid digital-to-analog (D-A) precoding system is investigated and a particle swarm optimisation (PSO) based joint D-A precoding optimisation algorithm is proposed. This algorithm maximises the capacity of the hybrid D-A mm-Wave massive MIMO system. The proposed algorithm is compared with three known hybrid D-A precoding algorithms. The analytical and simulation results show that the proposed algorithm achieves higher capacity than the existing hybrid D-A precoding algorithms.
3/30/2020 3:44:38 PM +00:00
An efficient CSI feedback scheme for dual-polarized massive MIMO
As an effective solution to the tradeoff between array size and the number of antenna elements, dual polarization antenna is widely utilized in massive MIMO systems. However, existing channel state information (CSI) feedback schemes are not suitable for dual-polarized massive MIMO as they ignore the polarization leakage between the polarization directions, causing significant performance degradation. To facilitate accurate channel acquisition, this paper proposes a practical channel model for dual-polarized massive MIMO by taking polarization leakage into consideration. The model formulates the channel as the sum of two components, i.e., the ideal polarization channel and the polarization leakage channel between the polarization directions.
3/30/2020 3:44:15 PM +00:00
Large-scale mimo MC-CDMA system using combined multiple beamforming and spatial multiplexing
This paper proposes a novel Large-scale (massive) Multi-input Multi-output Multicarrier Code division multiple access (LS MIMO MC-CDMA) model and application to the Fifth-Generation Mobile Communication Systems (5G). This system uses combined cylindrical array antenna multiple beamforming architecture with spatial multiplexing. The model is optimized by Min-Max criteria in order to minimize side lobes and maximize the reduction of propagation loss. The Monte Carlo simulation results unify with the analytical solution for system performance.
3/30/2020 3:44:02 PM +00:00
The bit interleaved coded modulation module for DVB-NGH: enhanced features for mobile reception
This paper describes the main features of the DVBNGH Bit-Interleaved Coded Modulation (BICM) module. This latter is derived from a sub-set of DVB-T2 BICM components with additional features intended to first lower receiver complexity and power consumption and then to increase receiver robustness over mobile reception. Therefore, the long code block size was removed, a different range of coding rates was chosen, non-uniform constellations were adopted in order to provide shaping gain, and the principle of signal space diversity was extended to four-dimensional rotated constellations. Moreover the structure of the time interleaver offers the possibility to significantly increase the interleaving depth, a feature required for mobility over terrestrial and satellite links.
3/30/2020 3:43:54 PM +00:00
Performance of MIMO bit division with polarized MIMO DVB-T2
This paper introduces a principal concept of MIMO bit division and presents its performance with corresponding simulation results. When multiple antenna technique is applied to enhance the spectral efficiency, the original data stream should be divided in a proper way. We found that the way of dividing original data stream, if it is not cooperating well with the originally structured system, may lead to performance degradation. The key idea is dividing the original data bit stream without causing an undesired change of bit order at the output of bit-to-cell demux.
3/30/2020 3:43:40 PM +00:00
Joint beamforming and broadcasting in Massive MIMO
The downlink of a massive MIMO system is considered for the case in which the base station must concurrently serve two categories of terminals: one group to which imperfect instantaneous channel state information (CSI) is available, and one group to which no CSI is available. Motivating applications include broadcasting of public channels and control information in wireless networks.
3/30/2020 3:43:19 PM +00:00
Hybrid digital and analog beamforming design for large-scale antenna arrays
The potential of using of millimeter wave (mmWave) frequency for future wireless cellular communication systems has motivated the study of large-scale antenna arrays for achieving highly directional beamforming. However, the conventional fully digital beamforming methods which require one radio frequency (RF) chain per antenna element is not viable for large-scale antenna arrays due to the high cost and high power consumption of RF chain components in high frequencies. To address the challenge of this hardware limitation, this paper considers a hybrid beamforming architecture in which the overall beamformer consists of a low-dimensional digital beamformer followed by an RF beamformer implemented using analog phase shifters.
3/30/2020 3:42:52 PM +00:00
Hybrid beamforming for millimeter-wave heterogeneous networks
Heterogeneous networks (HetNets) employing massive multiple-input multiple-output (MIMO) and millimeter-wave (mmWave) technologies have emerged as a promising solution to enhance the network capacity and coverage of next-generation 5G cellular networks. However, the use of traditional fully-digital MIMO beamforming methods, which require one radio frequency (RF) chain per antenna element, is not practical for large-scale antenna arrays, due to the high cost and high power consumption. To reduce the number of RF chains, hybrid analog and digital beamforming has been proposed as an alternative structure. In this paper, therefore, we consider a HetNet formed with one macro-cell base station (MBS) and multiple small-cell base stations (SBSs) equipped with large-scale antenna arrays that employ hybrid analog and digital beamforming. The analog beamforming weight vectors of the MBS and the SBSs correspond to the the best-fixed multi-beams obtained by eigendecomposition schemes.
3/30/2020 3:42:24 PM +00:00
An optimized hybrid beamforming for millimeter wave mumassive MIMO system
Millimeter wave (mmWave) and massive multiple-input multiple-output communications (massive MIMO) have been adopted as the most important keys for the next generation (5G) wireless networks due to high spectrum availability and massive use of space diversity for high throughput communications. Massive MIMO must be implemented parallel with mmWave to overcome high path-loss issue in mmWave band by improving the antennas gain.
3/30/2020 3:42:03 PM +00:00
Cross-layer multi-user selection in 5G heterogeneous networks based on hybrid beamforming optimization for millimeter-waves
Lack of coordination between network layers limits the performance of most proposed solution for new challenges posed by wireless networks. To overcome such limitations, cross-layer physical and medium access (PHY-MAC) design for multi-input-multi-output orthogonal frequency division multiple access system in heterogeneous networks (HetNETs) is proposed. In this paper, we formulate an optimization problem for hybrid beamforming, in a multi-user HetNET scenario aiming to maximize the total system throughput. Furthermore, analog beamforming is selected from a codebook containing a limited number of candidates for steering vectors. The proposed problem is non-convex and hard to solve. Thus it is relaxed by transforming it into a subtraction form of two convex funcions.
3/30/2020 3:41:39 PM +00:00
Hybrid beamforming for relay-aided mmWave backhaul links
Massive multiple-input multiple-output (MIMO) and millimeter-wave (mmWave) technologies have emerged as a promising solution to enhance the backhaul wireless link in 5G Heterogeneous networks (HetNets). These mmWave backhaul links, however, are very susceptible to a significant path loss due to the blockage of the line-ofsight and massive antenna arrays may not be sufficient to alleviate such losses. To this end, relays are usually deployed to provide alternative routes that help boost links with high path loss. In this paper, therefore, we consider using relay base stations (RBS) in mmWave backhaul links between small cell base stations (SBS) and a macro-cell base station (MBS). It is assumed that the SBSs, the RBSs, and the MBS are all equipped with massive antenna arrays employing hybrid analog and digital beamforming.
3/30/2020 3:41:05 PM +00:00
Hybrid beamforming for 5G millimeter-wave multi-cell networks
Multi-cell wireless systems usually suffer both intracell and inter-cell interference, which can be mitigated via coordinated multipoint (CoMP) techniques. Previous works on multi-cell analysis for the microwave band generally consider fully digital beamforming that requires a complete radio-frequency chain behind each antenna, which is less practical for millimeterwave (mmWave) systems where large amounts of antennas are necessary to provide sufficient beamforming gain and to enable transmission and reception of multiple data streams per user. This paper proposes four analog and digital hybrid beamforming schemes for multi-cell multi-user multi-stream mmWave communication, leveraging CoMP.
3/30/2020 3:40:29 PM +00:00
A MIMO-channel-precoding scheme for next generation terrestrial broadcast TV systems
In this paper we propose a MIMO channelprecoder that utilizes channel statistical structure and is suitable for terrestrial broadcasting systems, while being potentially transparent to the receivers. The performance of the channel-precoder is evaluated in a wide set of channel scenarios and mismatched channel conditions, a typical situation in the broadcast setup.
3/30/2020 3:40:08 PM +00:00
Overview of the scalable video coding extension of the H.264/AVC standard
These functionalities provide enhancements to transmission and storage applications. SVC has achieved significant improvements in coding efficiency with an increased degree of supported scalability relative to the scalable profiles of prior video coding standards. This paper provides an overview of the basic concepts for extending H.264/AVC towards SVC. Moreover, the basic tools for providing temporal, spatial, and quality scalability are described in detail and experimentally analyzed regarding their efficiency and complexity.
3/30/2020 3:39:55 PM +00:00
Advanced network planning for time frequency slicing (TFS) towards enhanced efficiency of the next-generation terrestrial broadcast networks
The allocation of frequencies traditionally used by terrestrial broadcasting (digital dividend) to International Mobile Telecommunication (IMT) is limiting the evolution of the Digital Terrestrial Television (DTT) networks for enhanced service offering. Next-generation DTT standards are called to provide increased capacity within the reduced spectrum. Time Frequency Slicing (TFS) has been proposed as one of the key technologies for the future DTT networks. Beyond a coverage gain due to additional frequency diversity, and a virtual capacity gain due to a more efficient statistical multiplexing, TFS also provides an increased interference immunity which may allow for a tighter frequency reuse enabling more RF channels per transmitter station, within a given spectrum.
3/30/2020 3:39:45 PM +00:00
Multi – element antenna for Dvb – H terminal
In this thesis feasibility to implement multi-element antenna configurations in handheld digital television receivers (Digital Video Broadcasting – Handheld (DVB-H)) has been studied. A two-element antenna for a DVB-H terminal was designed, manufactured and the performance of the antenna was evaluated with simulations and measurements.
3/30/2020 3:11:59 PM +00:00
The bit interleaved coded modulation module for DVB-NGH
This paper describes the main features of the DVBNGH Bit-Interleaved Coded Modulation (BICM) module. This latter is derived from a sub-set of DVB-T2 BICM components with additional features intended to first lower receiver complexity and power consumption and then to increase receiver robustness over mobile reception. Therefore, the long code block size was removed, a different range of coding rates was chosen, non-uniform constellations were adopted in order to provide shaping gain, and the principle of signal space diversity was extended to four-dimensional rotated constellations. Moreover the structure of the time interleaver offers the possibility to significantly increase the interleaving depth, a feature required for mobility over terrestrial and satellite links.
3/30/2020 3:11:52 PM +00:00
Reduction of physical layer signaling overhead in DVB-NGH systems
The Digital Video Broadcasting Next Generation Handheld (DVB-NGH) standard has adopted many advanced technologies, including overhead reduction schemes, to maximize the system capacity. However, some of the overhead reduction schemes of Layer-l (LI) signaling result in increased initial capture time delays. In order to get a more flexible trade-off between overhead reduction and initial capture time delay, a full-truncated Ll signaling scheme is proposed in DVB-NGH systems. Simulation results demonstrate the effectiveness ofthe proposed scheme.
3/30/2020 3:11:43 PM +00:00
Performance analysis of DVB-NGH MIMO coded modulation system
Digital video broadcasting-next generation handheld (DVB-NGH) is the first broadcasting standard that incorporates multiple-input multiple-output (MIMO) techniques to overcome the Shannon limit of single antenna systems. This paper contributes to analyze the performance of the DVB-NGH MIMO coded modulation system. The detailed performance degradation from information-theoretic limit to implementation by average mutual information and extrinsic information transfer analysis is presented, which provides an insight guideline for future system improvement. Finally, bit error rate simulations are carried out to verify the analysis.
3/30/2020 3:11:20 PM +00:00
Integration of MIMO support in a DVB-T2 simulator
This thesis examines the benefits of using multi-antenna transmission in terrestrial digital video broadcasting, especially in the DVB-T2 and DVBNGH standards. The thesis extends an existing DVB-T2 simulator with a platform for running MIMO simulations. The platform is constructed in a manner that will allow it to be easily adapted to future needs.
3/30/2020 3:11:09 PM +00:00
Improved polarized 2x2 MIMO spatial multiplexing method for DVB-NGH system
Recently terrestrial digital broadcasting systems have experienced a growth with the demand of high-data rate. In order to meet such demand, the multiple-input multiple-output (MIMO) technology has received wide attention. This paper proposes a pre-coding method, which provides high-space channel correlation for the improved performance over terrestrial broadcasting channels when the MIMO spatial multiplexing (SM) is adopted for digital video broadcasting-next generation handheld systems. When signals with two different modulation orders are transmitted through two antennas, a method that is based on nonuniform power is also proposed for improved reception performance. To optimize the proposed method, phase shifting values for the pre-coding method and appropriate non-uniform power ratio are obtained. These obtained parameters are applied to a terrestrial broadcasting system, and then the performance improvement over the conventional SM is shown through computer simulations.
3/30/2020 3:11:01 PM +00:00
Impact of LTE and DVB-NGH cooperation on QoS of mobile TV users
We specifically evaluate the users QoS in terms of quantifiable metrics, notably the probability of service degradation due to non availability of LTE bearers, its frequency degradation.
3/30/2020 3:10:54 PM +00:00
Handheld receivers coverage by DVB-T2
It is expected that the upcoming DVB-NGH (Digital Video Broadcasting-Next Generation Handheld) shall be based on the existing DVB-T2 technology. Also DVB-NGH enabled Handheld receivers are going to work with the existing DVB infrastructure. In this paper we model the link budget deficits of the Handheld DVB receivers as additional power losses for a typical fixed roof-top DVB-T2 receiver. Because of those additional losses Handhelds get a reduced coverage. The attrition in coverage is especially dramatic for the indoor Handheld receivers. We analyze coverage for two different models of the Population density, i.e. Clark’s and Smeed’s.
3/30/2020 3:10:47 PM +00:00
Technical report TR 1.1 intermediate report on DVB-NGH concept studies
This report aims at synthesizing the main achievements and results obtained within task force TF1 during the first 18 months of the ENGINES project. This report comes as a mid-term technical report for TF1 and takes part in the overall technical work of work package WP2 “System Architecture”.
3/30/2020 3:10:33 PM +00:00
End-to-end digital video broadcasting test-bed
This article presents the research and development activities on digital video broadcasting carried by the Mobile Communications Group of the iTEAM research institute of the Universidad Politécnica de Valencia. iTEAM is a full member of the DVB standardization forum, and is actively participating in the standardization process of the next generation mobile TV standard DVB-NGH. iTEAM’s DVB facilities include a complete end-toend DVB-T/H/SH/T2 lab, and a DVB-T/H pilot at the main campus of the Universidad Politécnica de Valencia. iTEAM has developed a proprietary multi-standard DVB encapsulation, simulation, and measurement platforms. On-going work aims at upgrading the platforms with the second generation digital terrestrial television DVB-T2 standard.
3/30/2020 3:10:25 PM +00:00
Lesson DVB-NGH
DVB-NGH, the handheld evolution of the second-generation digital terrestrial TV standard DVB-T2. It uses some new technologies compared DVB-T2; layered video coding with multiple physical layer pipes; time-frequency slicing; full support of an IP transport layer with a dedicated protocol stack; header compression mechanisms for both IP and MPEG2 TS packets; non-uniform constellations for 64 Quadrature Amplitude Modulation (QAM) etc...
3/30/2020 3:10:19 PM +00:00
DVB-NGH: The next generation of digital broadcast services to handheld devices
This paper reviews the main technical solutions adopted by the next-generation mobile broadcasting standard DVB-NGH, the handheld evolution of the second-generation digital terrestrial TV standard DVB-T2. The main new technical elements introduced with respect to DVB-T2 are: layered video coding with multiple physical layer pipes, time-frequency slicing, full support of an IP transport layer with a dedicated protocol stack, header compression mechanisms for both IP and MPEG2 TS packets, new low-density parity check coding rates for the data path (down to 1/5), nonuniform constellations for 64 Quadrature Amplitude Modulation (QAM) and 256 QAM, 4-D rotated constellations for Quadrature Phase Shift Keying (QPSK), improved time interleaving in terms of zapping time, end-to-end latency and memory consumption, improved physical layer signaling in terms of robustness, capacity and overhead, a novel distributed multiple input–single output transmit diversity scheme for single-frequency networks (SFNs), and efficient provisioning of local content in SFNs.
3/30/2020 3:10:07 PM +00:00
DVB-NGH for next-generation digital broadcasting
Next generation broadcasting can be made compatible with today's ATSC DTV tuners and achieve the desired spectrum efficiency and interoperability with wireless broadband.
3/30/2020 3:10:00 PM +00:00
MIMO For DVB-NGH, the next generation mobile TV broadcasting
The paper also provides a feature comparison with the multi-antenna techniques for 3GGP´s LTE/LTE-Advanced for cellular networks. Finally, physical layer simulation results calibrated within the DVB-NGH standardization process are provided to illustrate the gain of MIMO for the next generation of mobile TV broadcasting.
3/30/2020 3:09:51 PM +00:00
Analytical analysis of implementation issues and its practical applicability in DVB-NGH single frequency networks
The role of the television has huge impact on the 21st century and basically the televisions either make use of SFN single frequency networks (SFN) or multi frequency networks (MFN) and both these networks are ideal for meeting the practical requirements either in local and global services. Another important drawback in these two networks are these two networks consumes huge amount of spectrum. The single frequency networks (SFN) main approach is it radiates the same amount of signal both in terms of time and frequency and Without violating the SFN principle, local services meant to address sub-regions of an SFN must therefore be transmitted throughout the whole network, causing inefficient distribution of local services. A novel approach has been proposed in this paper where high equipped next generation mobile broadcasting standard digital video broadcasting—next generation handheld for providing global and local contents in SFN topologies: hierarchical modulation (H-LSI) and orthogonal local services insertion (O-LSI) techniques. HLSI uses hierarchical modulation to transmit local services on top of the global services in areas close to the transmitters, by transmitting the local services in the low priority stream and the global services in the high priority stream.
3/30/2020 3:09:45 PM +00:00