LTE & LTE-A PROSPECTIVE OF MOBILE BROADBAND
|
|
- Patrick Sherman
- 5 years ago
- Views:
Transcription
1 International Journal of Recent Innovation in Engineering and Research Scientific Journal Impact Factor by SJIF e- ISSN: LTE & LTE-A PROSPECTIVE OF MOBILE BROADBAND G.Madhusudhan 1 and Ajay P Betur 2 1 Research Scholar Department of PG Studies & Research in Electronics Shankaraghatta Assistant Professor, Department of E &CE, JNNCE, Navule,Shivamogga Abstract- This paper provides an in-depth view on the technologies being considered for Long Term Evolution (LTE) and Long term Evolution -Advanced (LTE-Advanced). First, the evolution from third generation (3G) to fourth generation (4G) is described in terms of main characteristics and performance requirements, the new network architecture developed by the Third Generation Partnership Project (3GPP), which supports the integration of current and future radio access technologies which is highlighted. Then, the main technologies for LTE-Advanced are explained, together with possible improvements, their associated challenges, and theoretical approaches that have been considered to tackle those challenges. Through this paper a clear view regarding the Comparison between two giant outgrowth in modern era of mobile communication i.e. LTE and LTE-A can be drawn as per each key features concerned in both the standards. Keywords-LTE,Downlink,Uplink,lteadvanced,4G,Carrieaggregation,comp,Relay,MIMO,PDCCH, PUCCH. I. INTRODUCTION A. Evolution of wireless standards Wireless communications have evolved from the so-called second generation (2G) systems of the early 1990s, which first introduced digital cellular technology through the deployment of third generation (3G) systems with their higher speed data networks to the much-anticipated fourth generation technology being developed today. This evolution is illustrated in Figure 1, which shows that fewer standards are being proposed for 4G than in previous generations, with only two 4G candidates being actively developed today: 3GPP LTE-Advanced and IEEE m, which is the evolution of the WiMAX standard known as M obile WiMAX. Figure 1: Wireless evolution and beyond LTE (both radio and core network evolution) is now in the market. Release 8 was frozen in December 2008 and this has been the basis for the first wave of LTE equipment. LTE specifications are very stable, with the added benefit of enhancements having been introduced in all subsequent 3GPP Releases. B. The motivation for LTE Need to ensure the continuity of competitiveness of the 3G system for the future. User demand for higher data rates and quality of service Packet Switch optimized system. Continued demand for cost reduction (CAPEX and rights Reserved Page 35
2 Low complexity; avoid unnecessary fragmentation of technologies for paired and unpaired band operation. Figure 2: LTE system II. SUMMARY OF LTE FEATURES The Long Term Evolution project was initiated in The motivation for LTE included the desire for a reduction in the cost per bit, the addition of lower cost services with better user experience, the flexible use of new and existing frequency bands, a simplified and lower cost network with open interfaces and a reduction in terminal complexity with an allowance for reasonable power consumption. These high level goals led to further expectations for LTE, including reduced latency for packets, and spectral efficiency improvements above Release 6 high speed packet access (HSPA) of three to four times in the downlink and two to three times in the uplink. Flexible channel bandwidths a key feature of LTE are specified at 1.4, 3, 5, 10, 15, and 20 MHz in both the uplink and the downlink. This allows LTE to be flexibly deployed where other systems exist today, including narrowband systems such as GSM and some systems in the U.S. based on 1.25 MHz. Speed is probably the feature most associated with LTE. Examples of downlink and uplink peak data rates for a 20 MHz channel bandwidth are shown in Table 1. Downlink figures are shown for single input single output (SISO) and multiple input multiple output (MIMO) antenna configurations at a fixed 64QAM modulation depth, whereas the uplink figures are for SISO but at different modulation depths. These figures represent the physical limitation of the LTE frequency division duplex (FDD) radio access mode in ideal radio conditions with allowance for signaling overheads. Lower rates are specified for specific UE categories and performance requirements under non-ideal radio conditions have also been developed. Table [1] for LTE s time division duplex (TDD) radio access mode are comparable, scaled by the variable uplink and downlink ratios. Table 1: Uplink and Downlink data rates. Unlike previous systems, LTE is designed from the beginning to use MIMO technology, which results in a more integrated approach to this advanced antenna technology than does the addition of MIMO to legacy system such as HSPA. Finally, in terms of mobility, LTE is aimed primarily at low mobility applications in the 0 to 15 km/h range, where the highest performance will be seen. The system is capable of working at higher speeds and will be supported with high performance from 15 to 120 km/h and functional support from 120 to 350 km/h. Support for speeds of 350 to 500 km/h is under consideration. A. Radio Interface Concepts Of LTE The ability to provide a high bit rate is a key measure for LTE. LTE is designed to meet the requirements of peak data rate up to 150 Mbps in down-link, 75 Mbps at up-link. The characteristics of LTE will be cellular coverage, Mobility, scalable bandwidth of 1.3, 3, 5, 10, 15, 20 MHz, FDD (Frequency Division Duplexing) and TDD (Time Division Duplexing). Thedown-link by OFDMA Available Online at : Page 36
3 (Orthogonal Frequency Division Multiplexing Access), up-link by SCFDMA (Single Carrier Frequency Division Multiplexing Access), MIMO (Multiple Input Multiple Output), and modulations by 16 QAM, 64 QAM technologies are used by LTE for meeting the data rate requirements mentioned above. B. Down-link OFDMA OFDMA is a multi-user version of a digital modulation scheme called Orthogonal Frequency-Division Multiplexing (OFDM). In OFDM the signal is first split into independent subcarriers and these closely-spaced orthogonal subcarriers are used to carry the data. The data is divided into several parallel data streams or channels, one for each subcarrier. Each sub-carrier is modulated with a conventional modulation scheme (such as quadrature amplitude modulation or phase shift keying) at a low symbol rate, maintaining total data rates similar to conventional single carrier modulation schemes of the same bandwidth[3]. A general analogy for OFDM can be of many small lamps in a hall rather than a single big lamp. The advantage is that light will be distributed across the hall equally as compared to a single lamp and increase redundancy a defect in one lamp will not affect the light in the hall. The primary advantage of OFDM over single-carrier scheme is its ability to cope with severe channel conditions without complex equalization filters. For example, attenuation of high frequencies in a long copper wire, narrowband interference and frequencyselective fading due to multipath. Figure 3: Multi Path Fading With the help of OFDM, channel equalization is simplified as OFDM may be viewed as using many slowly-modulated narrowband signals rather than one rapidly-modulated wideband signal. With the duration of each symbol being long, it is feasible to insert a guard interval between the OFDM, making it possible to handle time-spreading and eliminate inter-symbol interference (ISI). This mechanism also facilitates the design of single-frequency networks, where several adjacent transmitters send the same signal simultaneously at the same frequency. As the signals from multiple distant transmitters may be combined constructively, rather than interfering as would typically occur in a traditional single-carrier system. C. Uplink Single-Carrier FDMA with Dynamic Bandwidth To improve the RF transmission power efficiency in the UE, Single Carrier Frequency Division Multiple Access (SCFDMA) is used. SC-FDMA has similar performance and essentially the same overall structure as those of an OFDM. A system one prominent advantage of SC-FDMA over OFDMA is that the SC-FDMA signal has lower peak-to-average power ratio (PAPR). In the uplink communications low PAPR greatly benefits the User Equipment (UE) in terms of transmit power efficiency. Guard intervals with cyclic repetition are introduced between blocks of symbols as in OFDM explained earlier. In OFDM, FFT is applied on the receiver side on each block of symbols, and IFFT on the transmitter side. In SC-FDMA, both FFT and IFFT are applied on the transmitter side, and also on the receiver side. However SC-FDMA requires transmissions in consecutive bands, and thus introduces restrictions on the frequency domain packet scheduling for individual users compared to OFDMA. Available Online at : Page 37
4 D. Multi-Antenna Solutions Multiple Input Multiple Output (MIMO) is the major feature used to improve the performance of the LTE system, it allows in improving the spectral efficiency and data throughput[4]. MIMO consists of multiple antennas on the receiver and transmitter to utilize the multipath effects. This reduces the interference and leads to high throughputs. Multipath occurs when the different signals arrive at the receiver at various times intervals. MIMO divides a data stream into multiple unique streams, transmits data streams in the same radio channel at the same time. The receiving end uses an algorithm or employs special signal processing to generate one signal that was originally transmitted from the multiple signals. Figure 4: MIMO Block In LTE, the MIMO concepts vary from down-link to up-link to keep the terminal (UE) cost low. The base station either consists of two or four transmitting antennas and two receiving antennas on the terminal (UE) side for the down-link, and UE employs MU-MIMO (Multi User MIMO) for the up-link. With this scheme UE only have one transmit antenna which reduces the cost of the equipment. Interference due to transmission of data in the same channel by multiple mobile terminals is reduced by using mutually orthogonal pilot patterns. III. EVOLUTION OF LTE-ADVANCED LTE-A should be real broadband wireless network that provides peak data rates equal to or greater than those for wired networks, i.e., FTTH (Fiber To The Home), while providing better QoS. The major high-level requirements of LTEA are reduced network cost (cost per bit), better service provisioning and compatibility with 3GPP systems. LTE-A being an evolution from LTE is backward compatible. Some of the major technology proposals of LTE-A are : A. Asymmetric transmission bandwidth Access such as Frequency Division Duplex (FDD) and Time Division Duplex (TDD) are the two most prevalent duplexing schemes used in fixed broadband wireless networks. FDD uses two distinct radio channels and supports two-way radio communication and TDD uses a single frequency to transmit signals in both the downstream and upstream directions. Symmetric transmission results when the data in down-link and in the up-link are transmitted at the same data rate. This is one of the cases in voice transmission which transmits the same amount of data in both directions[5]. However, for internet connections or broadcast data (for example, streaming video), it is likely that more data will be sent from the server to the UE (the down-ink).based on the current and future traffic demands in cellular networks the required bandwidth in up-link will be narrower than that in down-link.so asymmetric transmission bandwidth will be a better solution for efficient utilization of the bandwidth. Figure 5: Support of Asymmetric Bandwidths for LTE Advanced Available Online at : Page 38
5 B. Layered OFDMA In layered structure, the entire system bandwidth comprises multiple basic frequency blocks. The bandwidth of basic frequency block is, MHz. Layered OFDMA radio access scheme in LTE-A will have layered transmission bandwidth, support of layered environments and control signal formats. The support of layered environments helps in achieving high data rate (user throughput), QoS, or widest coverage according to respective radio environments such as macro, micro, indoor, and hotspot cells. The control signal formats are a straightforward extensions of L1/L2 control signal formats of LTE to LTE-A. Independent control channel structure is used for each component carrier. Control channel supports only shared belonging to the same component carrier. C. Advanced Multi-cell Transmission/Reception Techniques In a multi-user multi-cell environment employing multi-transmission/reception antenna devices for each cell have multiple first units and a second units in wireless communication. The first units consists of a predetermined antenna and the second unit consists of the following sub units: a. Estimation unit: Estimates channel information on signals from the individual first units and estimates information of noise and interference signals from adjacent cells. b. Calculation unit: Calculates the sum of transfer rates for each user group having at least one first unit using the information estimated by the estimation unit. c. Determination unit: Determines one user group by comparing the sum of the transfer rates of each user group calculated by the calculation unit. d. Feedback unit: Information on the user group determined by the determination unit is fed back to the first units of the corresponding cell. In LTE-A, the advanced multi-cell transmission/reception processes (also called as coordinated multipoint transmission/reception) helps in increasing frequency efficiency and cell edge user throughput. Faster handovers among different inter-cell sites are achieved by employing Inter- Cell Interference (ICI) management (that is, inter-cell interference coordination (ICIC) aiming at inter-cell orthogonalization). D. Enhanced Multi-antenna Transmission Techniques Mobile traffic in wireless communications has been increasing multi folds over the years, which amplifier the requirement of higher-order MIMO channel transmissions and higher peak frequency efficiency than LTE. In LTE-A, the MIMO scheme has to be further improved in the area of spectrum efficiency, average cell throughput and cell edge performances. With multipoint transmission/reception, where antennas of multiple cell sites are utilized in such a way that the transmitting/receiving antennas of the serving cell and the neighboring cells can improve quality of the received signal at the UE/eNodeB and reduces the co-channel interferences from neighboring cells. Peak spectrum efficiency is directly proportional to the number of antennas used[6]. In LTE-A the antenna configurations of 8x8 in DL and 4x4 in UL are planned. Figure 6: MIMO Tx & Rx Schemes LTE-A (8 X 4 MIMO) Available Online at : Page 39
6 E. Enhanced Techniques to Extend Coverage Area Remote Radio Requirements (RREs) using optical fiber should be used in LTE-A as effective technique to extend cell coverage. Layer 1 relays with non-regenerative transmission, that is, repeaters can also be used for improving coverage in existing cell areas[7]. Layer 2 and Layer 3 relays can achieve wide coverage extension through an increase in Signal to Noise Ratio (SNR) Figure 7: RRE using optical fibers F. Support of Larger Bandwidth in LTE-Advanced Peak data rates up to 1Gbps are expected from bandwidths of 100MHz. OFDM adds additional sub-carrier to increase bandwidth. The available bandwidth may not be continuous as a result of fragmented spectrum[8]. To ensure backward compatibility to the current LTE, the control channels such as synchronization, broadcast, or PDCCH/PUCCH might be needed for every 20 MHz. Figure 8: Support of larger Bandwidths PDCCH stands for Physical Downlink Shared Channel whereas PUCCH stands for Physical Uplink Shared Channel used in synchronization broadcasting. The above described technology proposals of LTE-A[8] will help us to: Lower the total cost of network ownership. Easily deploy the network. Increase user throughput for fully multi-media feature services. Achieve spectrum flexibility support scalable bandwidth and spectrum aggregation. Achieve backward compatibility and inter-working with LTE with 3GPP legacy systems. Enable extended multi-antenna deployments and denser infrastructure in a cost-efficient way. IV. ADVANTAGES Some advantages that are applicable to the 4th Generation mobile communications are also applicable to LTE-A.With average download speeds of 400 Kbps to 700 Kbps, the network offers enough bandwidth to enable cell phone users to surf and download data from the Internet. LTE-A should significantly lower the bit-cost for the end-users and the total cost of ownership for the operators. At the same time, LTE-A should meet new emerging challenges such as energy-efficient Radio Access Network (RAN) design, increase the flexibilities of network deployments, and off load networks from localized user communications. Regardless of the actual technology, the forthcoming technology will also be able to allow the complete interoperability among heterogeneous networks and associated technologies, thus providing clear advantages in terms of: Coverage: The user gets best QoS and widespread network coverage as there is network availability at any given time. Available Online at : Page 40
7 Bandwidth: Sharing the resources among the various networks will reduce the problems of spectrum limitations of the third generation. V. KEY FEATURES Friendliness and Personalization: User friendliness exemplifies and minimizes the interaction between applications and the user. Thanks to a well designed transparency that allows the person and the machine to interact naturally (for example, the integration of new speech interface is a great step to achieve this goal). Heterogeneous Services: Services that are heterogeneous in nature (for example, different types of services such as audio, video etc.) such as quality and accessibility may not be the same due to the heterogeneity of the network. For instance, a user in proximity of the shopping mall but out of the coverage of a WLAN can still receive pop-up advertisements using the multi-hop ad hoc network setup in his surrounding. VI. COMPARISION BETWEEN LTE AND LTE-ADVANCED Comparison of performance requirements of LTE with Advanced and IMT-Advanced (4G) Table [2] are: some of the current agreements of LTE Table 2: Difference between LTE and LTE-A Available Online at : Page 41
8 VII. LTE-ADVANCED FREQUENCY BANDS Operating bands of LTE and LTE-A are identified by ITU-R. E-UTRA (LTE) are shown in Table[ 3]. g bands for Table 3: Operating bands for LTE / LTE-Advanced VIII. CONCLUSION LTE system has brought the wings for newer technologies in the world of communication standards. Whereas LTE-A helps in integrating the existing networks with new networks, services and terminals to suit the escalating user demands. The technical features of LTE-A may be summarized with the word integration. LTE-Advanced will be standardized in the 3GPP specification Release 10 (Release 10 LTE-A) and will be designed to meet the 4G requirements as defined by ITU. LTE-A as a system needs to take many features into considerations due to optimization at each level which involves lots of complexity and challenging implementation. Numerous changes on the physical layer can be expected to support larger bandwidths with more flexible allocations and to make use of further enhanced antenna technologies. Coordinated base stations, scheduling, MIMO, interference management and suppression will also require changes on the network architecture. REFERENCES [1] Rohde & Schwarz: Application Note 1MA111.UMTS Long Term Evolution (LTE)Technology Introduction. [2] Rohde & Schwarz: Application Note 1MA166.LTE-Advanced Signals Generation and. Analysis. [3] 3GPP TR V , March 2011; Technical Specification Group Radio Access Network; Feasibility study for further advancements for E-UTRA (LTE Advanced), Release 10 [4] 3GPP TR V , March 2011; Technical Specification Group Radio Access Network; Requirements for further advancements for Evolved Universal Terrestrial Radio Access (E-UTRA) LTE-Advanced, Release 10 [5] 3GPP TS V10.6.0, March 2012; Technical Specification Group Radio Access Network; Evolved Universal Terrestrial Radio Access (E-UTRA); User Equipment (UE) radio transmission and reception, Release 10 [6] 3GPP, TR , Evolved Universal Terrestrial Radio Access (E-UTRA); Long Term Evolution (LTE) physical layer; General description [7] H. Ekström et al., Technical Solutions for the 3G Long-term Evolution, IEEE Communications Magazine. Available Online at : Page 42
9 [8] 3GPP TSG RAN Tdoc RP [9] 3GPP TR V9.0.0 ( ), Requirements for Further Advancements of E-UTRA (LTE-Advanced). [10] ITU-R M.[IMT-TECH] Requirements related to technical performance for IMT-Advanced radio interface(s), [11] Madhusudhan G., S.V.Mahapurush, Dr.Priyatam Kumar, CELLULAR NETWORK TO THE LTE SYSTEM, International Conference on Electrical Electronics and Data Communication (ICEEDC) in Association with institute of research and journals, 5th July Vol.08, pp: ISBN: Bangalore, India. Available Online at : Page 43
Radio Interface and Radio Access Techniques for LTE-Advanced
TTA IMT-Advanced Workshop Radio Interface and Radio Access Techniques for LTE-Advanced Motohiro Tanno Radio Access Network Development Department NTT DoCoMo, Inc. June 11, 2008 Targets for for IMT-Advanced
More informationTechnical Aspects of LTE Part I: OFDM
Technical Aspects of LTE Part I: OFDM By Mohammad Movahhedian, Ph.D., MIET, MIEEE m.movahhedian@mci.ir ITU regional workshop on Long-Term Evolution 9-11 Dec. 2013 Outline Motivation for LTE LTE Network
More informationPlanning of LTE Radio Networks in WinProp
Planning of LTE Radio Networks in WinProp AWE Communications GmbH Otto-Lilienthal-Str. 36 D-71034 Böblingen mail@awe-communications.com Issue Date Changes V1.0 Nov. 2010 First version of document V2.0
More informationRadio Access Techniques for LTE-Advanced
Radio Access Techniques for LTE-Advanced Mamoru Sawahashi Musashi Institute of of Technology // NTT DOCOMO, INC. August 20, 2008 Outline of of Rel-8 LTE (Long-Term Evolution) Targets for IMT-Advanced Requirements
More informationInterference management Within 3GPP LTE advanced
Interference management Within 3GPP LTE advanced Konstantinos Dimou, PhD Senior Research Engineer, Wireless Access Networks, Ericsson research konstantinos.dimou@ericsson.com 2013-02-20 Outline Introduction
More informationPage 1. Overview : Wireless Networks Lecture 9: OFDM, WiMAX, LTE
Overview 18-759: Wireless Networks Lecture 9: OFDM, WiMAX, LTE Dina Papagiannaki & Peter Steenkiste Departments of Computer Science and Electrical and Computer Engineering Spring Semester 2009 http://www.cs.cmu.edu/~prs/wireless09/
More informationLecture LTE (4G) -Technologies used in 4G and 5G. Spread Spectrum Communications
COMM 907: Spread Spectrum Communications Lecture 10 - LTE (4G) -Technologies used in 4G and 5G The Need for LTE Long Term Evolution (LTE) With the growth of mobile data and mobile users, it becomes essential
More informationLong Term Evolution (LTE) and 5th Generation Mobile Networks (5G) CS-539 Mobile Networks and Computing
Long Term Evolution (LTE) and 5th Generation Mobile Networks (5G) Long Term Evolution (LTE) What is LTE? LTE is the next generation of Mobile broadband technology Data Rates up to 100Mbps Next level of
More informationFurther Vision on TD-SCDMA Evolution
Further Vision on TD-SCDMA Evolution LIU Guangyi, ZHANG Jianhua, ZHANG Ping WTI Institute, Beijing University of Posts&Telecommunications, P.O. Box 92, No. 10, XiTuCheng Road, HaiDian District, Beijing,
More informationLong Term Evolution (LTE)
1 Lecture 13 LTE 2 Long Term Evolution (LTE) Material Related to LTE comes from 3GPP LTE: System Overview, Product Development and Test Challenges, Agilent Technologies Application Note, 2008. IEEE Communications
More information3GPP: Evolution of Air Interface and IP Network for IMT-Advanced. Francois COURAU TSG RAN Chairman Alcatel-Lucent
3GPP: Evolution of Air Interface and IP Network for IMT-Advanced Francois COURAU TSG RAN Chairman Alcatel-Lucent 1 Introduction Reminder of LTE SAE Requirement Key architecture of SAE and its impact Key
More information3G long-term evolution
3G long-term evolution by Stanislav Nonchev e-mail : stanislav.nonchev@tut.fi 1 2006 Nokia Contents Radio network evolution HSPA concept OFDM adopted in 3.9G Scheduling techniques 2 2006 Nokia 3G long-term
More informationUniversity of Bristol - Explore Bristol Research. Link to publication record in Explore Bristol Research PDF-document.
Mansor, Z. B., Nix, A. R., & McGeehan, J. P. (2011). PAPR reduction for single carrier FDMA LTE systems using frequency domain spectral shaping. In Proceedings of the 12th Annual Postgraduate Symposium
More informationInvestigation on Multiple Antenna Transmission Techniques in Evolved UTRA. OFDM-Based Radio Access in Downlink. Features of Evolved UTRA and UTRAN
Evolved UTRA and UTRAN Investigation on Multiple Antenna Transmission Techniques in Evolved UTRA Evolved UTRA (E-UTRA) and UTRAN represent long-term evolution (LTE) of technology to maintain continuous
More informationLTE Aida Botonjić. Aida Botonjić Tieto 1
LTE Aida Botonjić Aida Botonjić Tieto 1 Why LTE? Applications: Interactive gaming DVD quality video Data download/upload Targets: High data rates at high speed Low latency Packet optimized radio access
More informationAll rights reserved. Mobile Developments. Presented by Philippe Reininger, Chairman of 3GPP RAN WG3
http://eustandards.in/ Mobile Developments Presented by Philippe Reininger, Chairman of 3GPP RAN WG3 Introduction 3GPP RAN has started a new innovation cycle which will be shaping next generation cellular
More information2012 LitePoint Corp LitePoint, A Teradyne Company. All rights reserved.
LTE TDD What to Test and Why 2012 LitePoint Corp. 2012 LitePoint, A Teradyne Company. All rights reserved. Agenda LTE Overview LTE Measurements Testing LTE TDD Where to Begin? Building a LTE TDD Verification
More information3G Evolution HSPA and LTE for Mobile Broadband Part II
3G Evolution HSPA and LTE for Mobile Broadband Part II Dr Stefan Parkvall Principal Researcher Ericsson Research stefan.parkvall@ericsson.com Outline Series of three seminars I. Basic principles Channel
More informationReferences. What is UMTS? UMTS Architecture
1 References 2 Material Related to LTE comes from 3GPP LTE: System Overview, Product Development and Test Challenges, Agilent Technologies Application Note, 2008. IEEE Communications Magazine, February
More information2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media,
2016 IEEE. Personal use of this material is permitted. Permission from IEEE must be obtained for all other uses, in any current or future media, including reprinting/republishing this material for advertising
More informationPhysical Layer Frame Structure in 4G LTE/LTE-A Downlink based on LTE System Toolbox
IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-issn: 2278-2834,p- ISSN: 2278-8735.Volume 1, Issue 3, Ver. IV (May - Jun.215), PP 12-16 www.iosrjournals.org Physical Layer Frame
More informationBeamforming for 4.9G/5G Networks
Beamforming for 4.9G/5G Networks Exploiting Massive MIMO and Active Antenna Technologies White Paper Contents 1. Executive summary 3 2. Introduction 3 3. Beamforming benefits below 6 GHz 5 4. Field performance
More informationAddressing Future Wireless Demand
Addressing Future Wireless Demand Dave Wolter Assistant Vice President Radio Technology and Strategy 1 Building Blocks of Capacity Core Network & Transport # Sectors/Sites Efficiency Spectrum 2 How Do
More informationData and Computer Communications. Tenth Edition by William Stallings
Data and Computer Communications Tenth Edition by William Stallings Data and Computer Communications, Tenth Edition by William Stallings, (c) Pearson Education - 2013 CHAPTER 10 Cellular Wireless Network
More informationPerformance Analysis of LTE System in term of SC-FDMA & OFDMA Monika Sehrawat 1, Priyanka Sharma 2 1 M.Tech Scholar, SPGOI Rohtak
Performance Analysis of LTE System in term of SC-FDMA & OFDMA Monika Sehrawat 1, Priyanka Sharma 2 1 M.Tech Scholar, SPGOI Rohtak 2 Assistant Professor, ECE Deptt. SPGOI Rohtak Abstract - To meet the increasing
More informationSEN366 (SEN374) (Introduction to) Computer Networks
SEN366 (SEN374) (Introduction to) Computer Networks Prof. Dr. Hasan Hüseyin BALIK (8 th Week) Cellular Wireless Network 8.Outline Principles of Cellular Networks Cellular Network Generations LTE-Advanced
More informationNew Cross-layer QoS-based Scheduling Algorithm in LTE System
New Cross-layer QoS-based Scheduling Algorithm in LTE System MOHAMED A. ABD EL- MOHAMED S. EL- MOHSEN M. TATAWY GAWAD MAHALLAWY Network Planning Dep. Network Planning Dep. Comm. & Electronics Dep. National
More informationLTE-Advanced and Release 10
LTE-Advanced and Release 10 1. Carrier Aggregation 2. Enhanced Downlink MIMO 3. Enhanced Uplink MIMO 4. Relays 5. Release 11 and Beyond Release 10 enhances the capabilities of LTE, to make the technology
More informationLTE-ADVANCED - WHAT'S NEXT? Meik Kottkamp (Rohde & Schwarz GmBH & Co. KG, Munich, Germany;
Proceedings of SDR'11-WInnComm-Europe, 22-24 Jun 2011 LTE-ADVANCED - WHAT'S NEXT? Meik Kottkamp (Rohde & Schwarz GmBH & Co. KG, Munich, Germany; meik.kottkamp@rohde-schwarz.com) ABSTRACT From 2009 onwards
More informationTesting of Early Applied LTE-Advanced Technologies on Current LTE Service to overcome Real Network Problem and to increase Data Capacity
Testing of Early Applied LTE-Advanced Technologies on Current LTE Service to overcome Real Network Problem and to increase Data Capacity Seung-Chul SHIN*, Young-Poong LEE** *Electronic Measurement Group,
More informationChannel Estimation for Downlink LTE System Based on LAGRANGE Polynomial Interpolation
Channel Estimation for Downlink LTE System Based on LAGRANGE Polynomial Interpolation Mallouki Nasreddine,Nsiri Bechir,Walid Hakimiand Mahmoud Ammar University of Tunis El Manar, National Engineering School
More informationLTE and NB-IoT. Luca Feltrin. RadioNetworks, DEI, Alma Mater Studiorum - Università di Bologna. Telecom Italia Mobile S.p.a. - TIM
LTE and NB-IoT Luca Feltrin RadioNetworks, DEI, Alma Mater Studiorum - Università di Bologna Telecom Italia Mobile S.p.a. - TIM Index Ø 3GPP and LTE Specifications Ø LTE o Architecture o PHY Layer o Procedures
More informationOutline / Wireless Networks and Applications Lecture 7: Physical Layer OFDM. Frequency-Selective Radio Channel. How Do We Increase Rates?
Page 1 Outline 18-452/18-750 Wireless Networks and Applications Lecture 7: Physical Layer OFDM Peter Steenkiste Carnegie Mellon University RF introduction Modulation and multiplexing Channel capacity Antennas
More informationBackground: Cellular network technology
Background: Cellular network technology Overview 1G: Analog voice (no global standard ) 2G: Digital voice (again GSM vs. CDMA) 3G: Digital voice and data Again... UMTS (WCDMA) vs. CDMA2000 (both CDMA-based)
More informationDownlink Scheduling in Long Term Evolution
From the SelectedWorks of Innovative Research Publications IRP India Summer June 1, 2015 Downlink Scheduling in Long Term Evolution Innovative Research Publications, IRP India, Innovative Research Publications
More informationUMTS Radio Access Techniques for IMT-Advanced
Wireless Signal Processing & Networking Workshop at Tohoku University UMTS Radio Access Techniques for IMT-Advanced M. M. Sawahashi,, Y. Y. Kishiyama,, and H. H. Taoka Musashi Institute of of Technology
More informationLTE-Advanced research in 3GPP
LTE-Advanced research in 3GPP GIGA seminar 8 4.12.28 Tommi Koivisto tommi.koivisto@nokia.com Outline Background and LTE-Advanced schedule LTE-Advanced requirements set by 3GPP Technologies under investigation
More information3G/4G Mobile Communications Systems. Dr. Stefan Brück Qualcomm Corporate R&D Center Germany
3G/4G Mobile Communications Systems Dr. Stefan Brück Qualcomm Corporate R&D Center Germany Chapter VI: Physical Layer of LTE 2 Slide 2 Physical Layer of LTE OFDM and SC-FDMA Basics DL/UL Resource Grid
More informationCapacity Enhancement Techniques for LTE-Advanced
Capacity Enhancement Techniques for LTE-Advanced LG 전자 윤영우연구위원 yw.yun@lge.com 1/28 3GPP specification releases 1999 2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 GSM/GPRS/EDGE enhancements
More informationTest Range Spectrum Management with LTE-A
Test Resource Management Center (TRMC) National Spectrum Consortium (NSC) / Spectrum Access R&D Program Test Range Spectrum Management with LTE-A Bob Picha, Nokia Corporation of America DISTRIBUTION STATEMENT
More informationContents. 1. HSPA & HSPA+ Overview. 2. HSDPA Introduction. 3. HSUPA Introduction. 4. HSPA+ Introduction
Contents 1. HSPA & HSPA+ Overview 2. HSDPA Introduction 3. HSUPA Introduction 4. HSPA+ Introduction Page58 All the HSPA+ Features in RAN11 and RAN12 3GPP Version HSPA+ Technology RAN Version Release 7
More informationLTE Long Term Evolution. Dibuz Sarolta
LTE Long Term Evolution Dibuz Sarolta History of mobile communication 1G ~1980s analog traffic digital signaling 2G ~1990s (GSM, PDC) TDMA, SMS, circuit switched data transfer 9,6kbps 2.5 G ~ 2000s (GPRS,
More informationRADIO LINK ASPECT OF GSM
RADIO LINK ASPECT OF GSM The GSM spectral allocation is 25 MHz for base transmission (935 960 MHz) and 25 MHz for mobile transmission With each 200 KHz bandwidth, total number of channel provided is 125
More informationFading & OFDM Implementation Details EECS 562
Fading & OFDM Implementation Details EECS 562 1 Discrete Mulitpath Channel P ~ 2 a ( t) 2 ak ~ ( t ) P a~ ( 1 1 t ) Channel Input (Impulse) Channel Output (Impulse response) a~ 1( t) a ~2 ( t ) R a~ a~
More information(COMPUTER NETWORKS & COMMUNICATION PROTOCOLS) Ali kamil Khairullah Number:
(COMPUTER NETWORKS & COMMUNICATION PROTOCOLS) Ali kamil Khairullah Number: 15505071 22-12-2016 Downlink transmission is based on Orthogonal Frequency Division Multiple Access (OFDMA) which converts the
More informationLTE-A Carrier Aggregation Enhancements in Release 11
LTE-A Carrier Aggregation Enhancements in Release 11 Eiko Seidel, Chief Technical Officer NOMOR Research GmbH, Munich, Germany August, 2012 Summary LTE-Advanced standardisation in Release 10 was completed
More information34 A. A. Oudah et al. / Jurnal Teknologi (Sciences & Engineering) 58 (2012) Suppl 1, 33 38
Jurnal Teknologi Full paper On The Evolution of LTE to LTE-Advanced A. A. Oudah a *, T. A. Rahman a, N. Seman a a Faculty of Electrical Engineering, Universiti Teknologi Malaysia, 81310 UTM Johor Bahru
More informationTesting Carrier Aggregation in LTE-Advanced Network Infrastructure
TM500 Family White Paper December 2015 Testing Carrier Aggregation in LTE-Advanced Network Infrastructure Contents Introduction... Error! Bookmark not defined. Evolution to LTE-Advanced... 3 Bandwidths...
More informationBroadcast Operation. Christopher Schmidt. University of Erlangen-Nürnberg Chair of Mobile Communications. January 27, 2010
Broadcast Operation Seminar LTE: Der Mobilfunk der Zukunft Christopher Schmidt University of Erlangen-Nürnberg Chair of Mobile Communications January 27, 2010 Outline 1 Introduction 2 Single Frequency
More informationWINNER+ IMT-Advanced Evaluation Group
IEEE L802.16-10/0064 WINNER+ IMT-Advanced Evaluation Group Werner Mohr, Nokia-Siemens Networks Coordinator of WINNER+ project on behalf of WINNER+ http://projects.celtic-initiative.org/winner+/winner+
More informationIntroduction to WiMAX Dr. Piraporn Limpaphayom
Introduction to WiMAX Dr. Piraporn Limpaphayom 1 WiMAX : Broadband Wireless 2 1 Agenda Introduction to Broadband Wireless Overview of WiMAX and Application WiMAX: PHY layer Broadband Wireless Channel OFDM
More informationChapter 6 Applications. Office Hours: BKD Tuesday 14:00-16:00 Thursday 9:30-11:30
Chapter 6 Applications 1 Office Hours: BKD 3601-7 Tuesday 14:00-16:00 Thursday 9:30-11:30 Chapter 6 Applications 6.1 3G (UMTS and WCDMA) 2 Office Hours: BKD 3601-7 Tuesday 14:00-16:00 Thursday 9:30-11:30
More informationOFDM AS AN ACCESS TECHNIQUE FOR NEXT GENERATION NETWORK
OFDM AS AN ACCESS TECHNIQUE FOR NEXT GENERATION NETWORK Akshita Abrol Department of Electronics & Communication, GCET, Jammu, J&K, India ABSTRACT With the rapid growth of digital wireless communication
More informationSC - Single carrier systems One carrier carries data stream
Digital modulation SC - Single carrier systems One carrier carries data stream MC - Multi-carrier systems Many carriers are used for data transmission. Data stream is divided into sub-streams and each
More informationS.D.M COLLEGE OF ENGINEERING AND TECHNOLOGY
VISHVESHWARAIAH TECHNOLOGICAL UNIVERSITY S.D.M COLLEGE OF ENGINEERING AND TECHNOLOGY A seminar report on Orthogonal Frequency Division Multiplexing (OFDM) Submitted by Sandeep Katakol 2SD06CS085 8th semester
More informationRadio Performance of 4G-LTE Terminal. Daiwei Zhou
Radio Performance of 4G-LTE Terminal Daiwei Zhou Course Objectives: Throughout the course the trainee should be able to: 1. get a clear overview of the system architecture of LTE; 2. have a logical understanding
More information5G Synchronization Aspects
5G Synchronization Aspects Michael Mayer Senior Staff Engineer Huawei Canada Research Centre WSTS, San Jose, June 2016 Page 1 Objective and outline Objective: To provide an overview and summarize the direction
More informationISSN (PRINT): , (ONLINE): , VOLUME-4, ISSUE-5,
PERFORMANCE ANALYSIS ON LTE BASED TRANSCEIVER DESIGN WITH DIFFERENT MODULATION SCHEMES Delson T R 1, Iven Jose 2 1 Research Scholar, ECE Department, 2 Professor, ECE Department Christ University, Bangalore,
More informationFrom 2G to 4G UE Measurements from GSM to LTE. David Hall RF Product Manager
From 2G to 4G UE Measurements from GSM to LTE David Hall RF Product Manager Agenda: Testing 2G to 4G Devices The progression of standards GSM/EDGE measurements WCDMA measurements LTE Measurements LTE theory
More information(LTE Fundamental) LONG TERMS EVOLUTION
(LTE Fundamental) LONG TERMS EVOLUTION 1) - LTE Introduction 1.1: Overview and Objectives 1.2: User Expectation 1.3: Operator expectation 1.4: Mobile Broadband Evolution: the roadmap from HSPA to LTE 1.5:
More informationCOMPARISON BETWEEN LTE AND WIMAX
COMPARISON BETWEEN LTE AND WIMAX RAYAN JAHA Collage of Information and Communication Engineering, Sungkyunkwan University, Suwon, Korea E-mail: iam.jaha@gmail.com Abstract- LTE and WiMAX technologies they
More informationWhite paper. Long Term HSPA Evolution Mobile broadband evolution beyond 3GPP Release 10
White paper Long Term HSPA Evolution Mobile broadband evolution beyond 3GPP Release 10 HSPA has transformed mobile networks Contents 3 Multicarrier and multiband HSPA 4 HSPA and LTE carrier 5 HSDPA multipoint
More informationSubmission on Proposed Methodology for Engineering Licenses in Managed Spectrum Parks
Submission on Proposed Methodology and Rules for Engineering Licenses in Managed Spectrum Parks Introduction General This is a submission on the discussion paper entitled proposed methodology and rules
More informationLow latency in 4.9G/5G
Low latency in 4.9G/5G Solutions for millisecond latency White Paper The demand for mobile networks to deliver low latency is growing. Advanced services such as robotics control, autonomous cars and virtual
More informationMulti-Cell Interference Coordination in LTE Systems using Beamforming Techniques
Multi-Cell Interference Coordination in LTE Systems using Beamforming Techniques Sérgio G. Nunes, António Rodrigues Instituto Superior Técnico / Instituto de Telecomunicações Technical University of Lisbon,
More informationCHAPTER 14 4 TH GENERATION SYSTEMS AND LONG TERM EVOLUTION
CHAPTER 14 4 TH GENERATION SYSTEMS AND LONG TERM EVOLUTION These slides are made available to faculty in PowerPoint form. Slides can be freely added, modified, and deleted to suit student needs. They represent
More informationPERFORMANCE ANALYSIS OF DOWNLINK MIMO IN 2X2 MOBILE WIMAX SYSTEM
PERFORMANCE ANALYSIS OF DOWNLINK MIMO IN 2X2 MOBILE WIMAX SYSTEM N.Prabakaran Research scholar, Department of ETCE, Sathyabama University, Rajiv Gandhi Road, Chennai, Tamilnadu 600119, India prabakar_kn@yahoo.co.in
More informationThe Next Generation Broadband Wireless Communication Network 3GPP-LTE - (Advanced)
The Next Generation Broadband Wireless Communication Network 3GPP-LTE - (Advanced) NCC 2012 Dr. Suvra Sekhar Das G.S. Sanyal of School of Telecommunications & Department of Electronics and Electrical Communications
More informationBASIC CONCEPTS OF HSPA
284 23-3087 Uen Rev A BASIC CONCEPTS OF HSPA February 2007 White Paper HSPA is a vital part of WCDMA evolution and provides improved end-user experience as well as cost-efficient mobile/wireless broadband.
More informationPerformance of Repeaters in 3GPP LTE ANTO SIHOMBING
Performance of Repeaters in 3GPP LTE ANTO SIHOMBING Master of Science Thesis Stockholm, Sweden 9 Performance of Repeaters in 3GPP LTE ANTO SIHOMBING Master of Science Thesis performed at the Radio Communication
More informationMIMO in 4G Wireless. Presenter: Iqbal Singh Josan, P.E., PMP Director & Consulting Engineer USPurtek LLC
MIMO in 4G Wireless Presenter: Iqbal Singh Josan, P.E., PMP Director & Consulting Engineer USPurtek LLC About the presenter: Iqbal is the founder of training and consulting firm USPurtek LLC, which specializes
More informationPart I Evolution. ZTE All rights reserved
Part I Evolution 2 ZTE All rights reserved 4G Standard Evolution, LTE-A in 3GPP LTE(R8/R9) DL: 100Mbps, UL: 50Mbps MIMO, BF,LCS, embms LTE-A (R10/R11) DL: 1Gbps, UL: 500Mbps CA, Relay, Het-Net CoMP, emimo
More informationOFDMA and MIMO Notes
OFDMA and MIMO Notes EE 442 Spring Semester Lecture 14 Orthogonal Frequency Division Multiplexing (OFDM) is a digital multi-carrier modulation technique extending the concept of single subcarrier modulation
More informationWireless Physical Layer Concepts: Part III
Wireless Physical Layer Concepts: Part III Raj Jain Professor of CSE Washington University in Saint Louis Saint Louis, MO 63130 Jain@cse.wustl.edu These slides are available on-line at: http://www.cse.wustl.edu/~jain/cse574-08/
More informationMillimeter-Wave Communication and Mobile Relaying in 5G Cellular Networks
Lectio praecursoria Millimeter-Wave Communication and Mobile Relaying in 5G Cellular Networks Author: Junquan Deng Supervisor: Prof. Olav Tirkkonen Department of Communications and Networking Opponent:
More informationImproving Peak Data Rate in LTE toward LTE-Advanced Technology
Improving Peak Data Rate in LTE toward LTE-Advanced Technology A. Z. Yonis 1, M.F.L.Abdullah 2, M.F.Ghanim 3 1,2,3 Department of Communication Engineering, Faculty of Electrical and Electronic Engineering
More informationLTE Air Interface. Course Description. CPD Learning Credits. Level: 3 (Advanced) days. Very informative, instructor was engaging and knowledgeable!
Innovating Telecoms Training Very informative, instructor was engaging and knowledgeable! Watch our course intro video. LTE Air Interface Course Description With the introduction of LTE came the development
More informationMobile Radio Systems (Wireless Communications)
Mobile Radio Systems (Wireless Communications) Klaus Witrisal witrisal@tugraz.at Signal Processing and Speech Communication Lab, TU Graz Lecture 1 WS2015/16 (6 October 2016) Key Topics of this Lecture
More informationA Polling Based Approach For Delay Analysis of WiMAX/IEEE Systems
A Polling Based Approach For Delay Analysis of WiMAX/IEEE 802.16 Systems Archana B T 1, Bindu V 2 1 M Tech Signal Processing, Department of Electronics and Communication, Sree Chitra Thirunal College of
More informationPerformance analysis of FFT based and Wavelet Based SC-FDMA in Lte
Performance analysis of FFT based and Wavelet Based SC-FDMA in Lte Shanklesh M. Vishwakarma 1, Prof. Tushar Uplanchiwar 2,Prof.MissRohiniPochhi Dept of ECE,Tgpcet,Nagpur Abstract Single Carrier Frequency
More information802.11ax Design Challenges. Mani Krishnan Venkatachari
802.11ax Design Challenges Mani Krishnan Venkatachari Wi-Fi: An integral part of the wireless landscape At the center of connected home Opening new frontiers for wireless connectivity Wireless Display
More informationGuide to Wireless Communications, Third Edition Cengage Learning Objectives
Guide to Wireless Communications, Third Edition Chapter 9 Wireless Metropolitan Area Networks Objectives Explain why wireless metropolitan area networks (WMANs) are needed Describe the components and modes
More informationVoice over IP Realized for the 3GPP Long Term Evolution
Voice over IP Realized for the 3GPP Long Term Evolution Fredrik Persson Ericsson Research Ericsson AB, SE-164 80 Stockholm, Sweden fredrik.f.persson@ericsson.com Abstract The paper outlines voice over
More informationPart 7. B3G and 4G Systems
Part 7. B3G and 4G Systems p. 1 Roadmap HSDPA HSUPA HSPA+ LTE AIE IMT-Advanced (4G) p. 2 HSPA Standardization 3GPP Rel'99: does not manage the radio spectrum efficiently when dealing with bursty traffic
More informationEvolution of 3GPP LTE-Advanced Standard toward 5G
Evolution of 3GPP LTE-Advanced Standard toward 5G KRNet 2013. 6. 24. LG Electronics Byoung-Hoon Kim (bh.kim@lge.com) Communication Standards Evolution Mobility We are here IMT-Advanced Standard High (~350Km/h)
More informationECS455: Chapter 6 Applications
ECS455: Chapter 6 Applications 6.2 WiMAX 1 Dr.Prapun Suksompong prapun.com/ecs455 Office Hours: BKD 3601-7 Wednesday 15:30-16:30 Friday 9:30-10:30 Advanced Mobile Wirless Systems (IEEE) (Ultra Mobile Broadband)
More informationBER Performance of OFDM-IDMA Comparison to OFDM for Femtocell
International Journal of Scientific and Research Publications, Volume 4, Issue 3, March 2014 1 BER Performance of OFDM-IDMA Comparison to OFDM for Femtocell Sandeep Kumar Dwivedi, Vaibhav Purwar, Sanjiv
More informationComparative Study of OFDM & MC-CDMA in WiMAX System
IOSR Journal of Electronics and Communication Engineering (IOSR-JECE) e-issn: 2278-2834,p- ISSN: 2278-8735.Volume 9, Issue 1, Ver. IV (Jan. 2014), PP 64-68 Comparative Study of OFDM & MC-CDMA in WiMAX
More informationUNIK4230: Mobile Communications. Abul Kaosher
UNIK4230: Mobile Communications Abul Kaosher abul.kaosher@nsn.com Multiple Access Multiple Access Introduction FDMA (Frequency Division Multiple Access) TDMA (Time Division Multiple Access) CDMA (Code
More informationEC 551 Telecommunication System Engineering Mohamed Khedr
EC 551 Telecommunication System Engineering Mohamed Khedr http://webmail.aast.edu/~khedr Syllabus Tentatively Week 1 Week 2 Week 3 Week 4 Week 5 Week 6 Week 7 Week 8 Week 9 Week 10 Week 11 Week 12 Week
More informationBlock Error Rate and UE Throughput Performance Evaluation using LLS and SLS in 3GPP LTE Downlink
Block Error Rate and UE Throughput Performance Evaluation using LLS and SLS in 3GPP LTE Downlink Ishtiaq Ahmad, Zeeshan Kaleem, and KyungHi Chang Electronic Engineering Department, Inha University Ishtiaq001@gmail.com,
More informationAcademic Course Description
Academic Course Description SRM University Faculty of Engineering and Technology Department of Electronics and Communication Engineering CO2110 OFDM/OFDMA Communications Third Semester, 2016-17 (Odd semester)
More informationWiMAX Summit Testing Requirements for Successful WiMAX Deployments. Fanny Mlinarsky. 28-Feb-07
WiMAX Summit 2007 Testing Requirements for Successful WiMAX Deployments Fanny Mlinarsky 28-Feb-07 Municipal Multipath Environment www.octoscope.com 2 WiMAX IP-Based Architecture * * Commercial off-the-shelf
More informationMobile Data Communication Terminals Compatible with Xi (Crossy) LTE Service
Mobile Data Communication Terminals Compatible with Xi (Crossy) LTE Service LTE Data communication terminal Throughput Special Articles on Xi (Crossy) LTE Service Toward Smart Innovation Mobile Data Communication
More informationMultiple Access Schemes
Multiple Access Schemes Dr Yousef Dama Faculty of Engineering and Information Technology An-Najah National University 2016-2017 Why Multiple access schemes Multiple access schemes are used to allow many
More informationRashad Irshad. MSC Radio and Mobile Communications. University of Hertfordshire, UK
SC-FDMA Technique for LTE Systems Rashad Irshad MSC Radio and Mobile Communications University of Hertfordshire, UK Abstract:- Due to the requirements of high speed and low delays it is very difficult
More informationMIMO Systems and Applications
MIMO Systems and Applications Mário Marques da Silva marques.silva@ieee.org 1 Outline Introduction System Characterization for MIMO types Space-Time Block Coding (open loop) Selective Transmit Diversity
More information3GPP TR V ( )
3rd Generation Partnership Project; Technical Specification Group Radio Access Network; Study on CU-DU lower layer split for NR; (Release 15) Technical Report The present document has been developed within
More informationNR Physical Layer Design: NR MIMO
NR Physical Layer Design: NR MIMO Younsun Kim 3GPP TSG RAN WG1 Vice-Chairman (Samsung) 3GPP 2018 1 Considerations for NR-MIMO Specification Design NR-MIMO Specification Features 3GPP 2018 2 Key Features
More information2016 Spring Technical Forum Proceedings
Full Duplex DOCSIS Technology over HFC Networks Belal Hamzeh CableLabs, Inc. Abstract DOCSIS 3.1 technology provides a significant increase in network capacity supporting 10 Gbps downstream capacity and
More information