LTE Advanced
Encyclopedia
LTE Advanced is a preliminary mobile communication standard, formally submitted as a candidate 4G
4G
In telecommunications, 4G is the fourth generation of cellular wireless standards. It is a successor to the 3G and 2G families of standards. In 2009, the ITU-R organization specified the IMT-Advanced requirements for 4G standards, setting peak speed requirements for 4G service at 100 Mbit/s...

 system to ITU-T
ITU-T
The ITU Telecommunication Standardization Sector is one of the three sectors of the International Telecommunication Union ; it coordinates standards for telecommunications....

 in late 2009, was approved into ITU, International Telecommunications Union, IMT-Advanced and expected to be finalized by 3GPP in early 2011. It is standardized by the 3rd Generation Partnership Project (3GPP) as a major enhancement of the 3GPP Long Term Evolution
3GPP Long Term Evolution
3GPP Long Term Evolution, usually referred to as LTE, is a standard for wireless communication of high-speed data for mobile phones and data terminals. It is based on the GSM/EDGE and UMTS/HSPA network technologies, increasing the capacity and speed using new modulation techniques...

 (LTE) standard.

Background

The LTE format was first proposed by NTT DoCoMo
NTT DoCoMo
is the predominant mobile phone operator in Japan. The name is officially an abbreviation of the phrase, "do communications over the mobile network", and is also from a compound word dokomo, meaning "everywhere" in Japanese. Docomo provides phone, video phone , i-mode , and mail services...

 of Japan and has been adopted as the international standards. LTE standardization has come to a mature state by now where changes in the specification are limited to corrections and bug fixes. The first commercial services were launched in Sweden
Sweden
Sweden , officially the Kingdom of Sweden , is a Nordic country on the Scandinavian Peninsula in Northern Europe. Sweden borders with Norway and Finland and is connected to Denmark by a bridge-tunnel across the Öresund....

 and Norway
Norway
Norway , officially the Kingdom of Norway, is a Nordic unitary constitutional monarchy whose territory comprises the western portion of the Scandinavian Peninsula, Jan Mayen, and the Arctic archipelago of Svalbard and Bouvet Island. Norway has a total area of and a population of about 4.9 million...

 in December 2009 followed by the United States and Japan in 2010. More first release LTE networks are expected to be deployed globally during 2010 as a natural evolution of several 2G and 3G systems, including Global system for mobile communications
Global System for Mobile Communications
GSM , is a standard set developed by the European Telecommunications Standards Institute to describe technologies for second generation digital cellular networks...

 (GSM) and Universal Mobile Telecommunications System
Universal Mobile Telecommunications System
Universal Mobile Telecommunications System is a third generation mobile cellular technology for networks based on the GSM standard. Developed by the 3GPP , UMTS is a component of the International Telecommunications Union IMT-2000 standard set and compares with the CDMA2000 standard set for...

 (UMTS) (3GPP
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...

 as well as 3GPP2).

Being described as a 3.9G (beyond 3G but pre-4G) technology the first release LTE does not meet the requirements for 4G
4G
In telecommunications, 4G is the fourth generation of cellular wireless standards. It is a successor to the 3G and 2G families of standards. In 2009, the ITU-R organization specified the IMT-Advanced requirements for 4G standards, setting peak speed requirements for 4G service at 100 Mbit/s...

—also called IMT Advanced
IMT Advanced
International Mobile Telecommunications-Advanced are requirements issued by the ITU-R of the International Telecommunication Union in 2008 for what is marketed as 4G mobile phone and Internet access service.-Description:...

 as defined by the International Telecommunication Union
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...

—such as peak data rates up to 1 Gbit/s. The ITU has invited the submission of candidate Radio Interface Technologies (RITs) following their requirements as mentioned in a circular letter. The work by 3GPP
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...

 to define a 4G
4G
In telecommunications, 4G is the fourth generation of cellular wireless standards. It is a successor to the 3G and 2G families of standards. In 2009, the ITU-R organization specified the IMT-Advanced requirements for 4G standards, setting peak speed requirements for 4G service at 100 Mbit/s...

 candidate radio interface technology started in Release 9 with the study phase for LTE-Advanced. The requirements for LTE-Advanced are defined in 3GPP Technical Report (TR) 36.913, "Requirements for Further Advancements for E-UTRA
E-UTRA
e-UTRAN or eUTRAN is the air interface of 3GPP's Long Term Evolution upgrade path for mobile networks. It is the abbreviation for evolved UMTS Terrestrial Radio Access Network, also referred to as the 3GPP work item on the Long Term Evolution also known as the Evolved Universal Terrestrial Radio...

 (LTE-Advanced)." These requirements are based on the ITU requirements for 4G
4G
In telecommunications, 4G is the fourth generation of cellular wireless standards. It is a successor to the 3G and 2G families of standards. In 2009, the ITU-R organization specified the IMT-Advanced requirements for 4G standards, setting peak speed requirements for 4G service at 100 Mbit/s...

 and on 3GPP
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...

 operators’ own requirements for advancing LTE. Major technical considerations include the following:
  • Continual improvement to the LTE radio technology and architecture
  • Scenarios and performance requirements for interworking with legacy radio access technologies
  • Backward compatibility of LTE-Advanced with LTE. An LTE terminal should be able to work in an LTE-Advanced network and vice versa. Any exceptions will be considered by 3GPP
    3GPP
    The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...

    .
  • Account taken of recent World Radiocommunication Conference
    World Radiocommunication Conference
    World Radiocommunication Conference is organized by ITU to review, and, as necessary, revise the Radio Regulations, the international treaty governing the use of the radio-frequency spectrum and the geostationary-satellite and non-geostationary-satellite orbits. It is held every three to four years...

     (WRC-07) decisions regarding new IMT spectrum as well as existing frequency bands to ensure that LTE-Advanced geographically accommodates available spectrum for channel allocations above 20 MHz. Also, requirements must recognize those parts of the world in which wideband channels are not available.


Likewise, 802.16m, 'WiMAX 2', has been approved by ITU into the IMT Advanced
IMT Advanced
International Mobile Telecommunications-Advanced are requirements issued by the ITU-R of the International Telecommunication Union in 2008 for what is marketed as 4G mobile phone and Internet access service.-Description:...

 family. WiMAX 2 is designed to be backward compatible with WiMAX 1/1.5 devices. Most vendors now support ease of conversion of earlier 'pre-4G', pre-advanced versions and some support software defined upgrades of core base station equipment from 3G.

The mobile communication industry and standardization organizations have therefore started to work on 4G access technologies such as LTE Advanced. At a workshop in April 2008 in China, 3GPP agreed the plans for future work on Long Term Evolution (LTE). A first set of 3GPP requirements on LTE Advanced has been approved in June 2008. Besides the peak data rate 1 Gbit/s that fully supports the 4G requirements as defined by the ITU-R, it also targets faster switching between power states and improved performance at the cell edge. Detailed proposals are being studied within the working group
Working group
A working group is an interdisciplinary collaboration of researchers working on new research activities that would be difficult to develop under traditional funding mechanisms . The lifespan of the WG can last anywhere between a few months and several years...

s.

Proposals

The target of 3GPP LTE Advanced is to reach and surpass the ITU
International Telecommunication Union
The International Telecommunication Union is the specialized agency of the United Nations which is responsible for information and communication technologies...

 requirements. LTE Advanced should be compatible with first release LTE equipment, and should share frequency bands with first release LTE. In the feasibility study for LTE Advanced, 3GPP
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...

 determined that LTE Advanced would meet the ITU-R
ITU-R
The ITU Radiocommunication Sector is one of the three sectors of the International Telecommunication Union and is responsible for radio communication....

 requirements for 4G
4G
In telecommunications, 4G is the fourth generation of cellular wireless standards. It is a successor to the 3G and 2G families of standards. In 2009, the ITU-R organization specified the IMT-Advanced requirements for 4G standards, setting peak speed requirements for 4G service at 100 Mbit/s...

. The results of the study are published in 3GPP
3GPP
The 3rd Generation Partnership Project is a collaboration between groups of telecommunications associations, known as the Organizational Partners...

 Technical Report (TR) 36.912.

One of the important LTE Advanced benefits is the ability to take advantage of advanced topology networks; optimized heterogeneous networks with a mix of macrocells with low power nodes such as picocell
Picocell
A picocell is a small cellular basestation typically covering a small area, such as in-building , or more recently in-aircraft...

s, femtocell
Femtocell
In telecommunications, a femtocell is a small cellular base station, typically designed for use in a home or small business. It connects to the service provider’s network via broadband ; current designs typically support 2 to 4 active mobile phones in a residential setting, and 8 to 16 active...

s and new relay nodes. The next significant performance leap in wireless networks will come from making the most of topology, and brings the network closer to the user by adding many of these low power nodes — LTE Advanced further improves the capacity and coverage, and ensures user fairness. LTE Advanced also introduces multicarrier to be able to use ultra wide bandwidth, up to 100 MHz of spectrum supporting very high data rates.

In the research phase many proposals have been studied as candidates for LTE Advance technologies. The proposals could roughly be categorized into:
  • Support for relay node base stations
  • Coordinated multipoint (CoMP) transmission and reception
  • UE Dual TX antenna solutions for SU-MIMO and diversity MIMO
    MIMO
    In radio, multiple-input and multiple-output, or MIMO , is the use of multiple antennas at both the transmitter and receiver to improve communication performance. It is one of several forms of smart antenna technology...

  • Scalable system bandwidth exceeding 20 MHz, Up to 100 MHz
  • Carrier aggregation of contiguous and non-contiguous spectrum allocations
  • Local area optimization of air interface
    Air interface
    In mobile or wireless communication, the air interface is the radio-based communication link between the mobile station and the active base station...

  • Nomadic / Local Area network and mobility solutions
  • Flexible spectrum usage
  • Cognitive radio
    Cognitive radio
    A cognitive radio is a kind of two-way radio that automatically changes its transmission or reception parameters, in a way where the entire wireless communication network -- of which it is a node -- communicates efficiently, while avoiding interference with licensed or licensed exempt users...

  • Automatic and autonomous network configuration and operation
  • Support of autonomous network and device test, measurement tied to network management and optimization
  • Enhanced precoding
    Precoding
    Precoding is a generalization of beamforming to support multi-layer transmission in multi-antenna wireless communications. In conventional single-layer beamforming, the same signal is emitted from each of the transmit antennas with appropriate weighting such that the signal power is maximized at...

     and forward error correction
    Forward error correction
    In telecommunication, information theory, and coding theory, forward error correction or channel coding is a technique used for controlling errors in data transmission over unreliable or noisy communication channels....

  • Interference management and suppression
  • Asymmetric bandwidth assignment for FDD
  • Hybrid OFDMA
    OFDMA
    Orthogonal Frequency-Division Multiple Access is a multi-user version of the popular Orthogonal frequency-division multiplexing digital modulation scheme. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users as shown in the illustration below...

     and SC-FDMA in uplink
  • UL/DL inter eNB coordinated MIMO
  • SONs, Self Organized Networks methodologies
  • Multiple carrier spectrum access.


Within the range of system development, LTE-Advanced and WiMAX 2, can use up to 8x8 MIMO and 128 QAM. Example performance: 100MHz aggregated bandwidth, LTE-Advanced provides almost 3.3Gbit peak download rates per sector of the base station under ideal conditions. Advanced network architectures combined with distributed and collaborative smart antenna technologies provide several years road map of commercial enhancements.

A summary of a study carried out in 3GPP can be found in TR36.912.

Timeframe

Standardization work was done in 3GPP Release 10, which was frozen in April 2011. Trials have taken place based on pre-release equipment. Major vendors support software upgrades to final versions and ongoing improvements.

Technology Demonstrations

  • In February 2007 NTT DoCoMo
    NTT DoCoMo
    is the predominant mobile phone operator in Japan. The name is officially an abbreviation of the phrase, "do communications over the mobile network", and is also from a compound word dokomo, meaning "everywhere" in Japanese. Docomo provides phone, video phone , i-mode , and mail services...

     announced the completion of a 4G trial where it achieved a maximum packet transmission rate of approximately 5 Gbit/s in the downlink using 100 MHz frequency bandwidth to a mobile station moving at 10 km/h.
  • In 2009, Rohde & Schwarz
    Rohde & Schwarz
    Rohde & Schwarz is an independent group of companies specializing in electronics. Well known as a manufacturer of electronic test equipment, they also manufacture equipment used for broadcasting, radiolocation, and radio communications...

     launched the CMW500 Wideband Communication Tester http://www2.rohde-schwarz.com/product/cmw500.html
  • In February 2011 at Mobile World Congress
    Mobile World Congress
    The GSMA Mobile World Congress is the combination of the world's largest exhibition for the mobile industry and a conference featuring prominent Chief Executives representing mobile operators, device manufacturers, technology providers, vendors and content owners from across the world...

    , Agilent Technologies
    Agilent Technologies
    Agilent Technologies , or Agilent, is a company that designs and manufactures electronic and bio-analytical measurement instruments and equipment for measurement and evaluation...

     demonstrated the industry's first test solutions for LTE-Advanced with both signal generation
    Signal generator
    Signal generators, also known variously as function generators, RF and microwave signal generators, pitch generators, arbitrary waveform generators, digital pattern generators or frequency generators are electronic devices that generate repeating or non-repeating electronic signals...

     and signal analysis
    Spectrum analyzer
    A spectrum analyzer measures the magnitude of an input signal versus frequency within the full frequency range of the instrument. The primary use is to measure the power of the spectrum of known and unknown signals...

     solutions.

External links


Resources (White papers, technical papers, application notes)

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