E-UTRA is the air interface of 3rd Generation Partnership Project (3GPP) Long Term Evolution (LTE) upgrade path for mobile networks. It is an acronym for Evolved UMTS Terrestrial Radio Access, [1] also known as the Evolved Universal Terrestrial Radio Access in early drafts of the 3GPP LTE specification. [1] E-UTRAN is the combination of E-UTRA, user equipment (UE), and a Node B (E-UTRAN Node B or Evolved Node B, eNodeB).
It is a radio access network (RAN) meant to be a replacement of the Universal Mobile Telecommunications System (UMTS), High-Speed Downlink Packet Access (HSDPA), and High-Speed Uplink Packet Access (HSUPA) technologies specified in 3GPP releases 5 and beyond. Unlike HSPA, LTE's E-UTRA is an entirely new air interface system, unrelated to and incompatible with W-CDMA. It provides higher data rates, lower latency and is optimized for packet data. It uses orthogonal frequency-division multiple access (OFDMA) radio-access for the downlink and single-carrier frequency-division multiple access (SC-FDMA) on the uplink. Trials started in 2008.
EUTRAN has the following features:
Although UMTS, with HSDPA and HSUPA and their evolution, deliver high data transfer rates, wireless data usage is expected to continue increasing significantly over the next few years due to the increased offering and demand of services and content on-the-move and the continued reduction of costs for the final user. This increase is expected to require not only faster networks and radio interfaces but also higher cost-efficiency than what is possible by the evolution of the current standards. Thus the 3GPP consortium set the requirements for a new radio interface (EUTRAN) and core network evolution (System Architecture Evolution SAE) that would fulfill this need.
These improvements in performance allow wireless operators to offer quadruple play services – voice, high-speed interactive applications including large data transfer and feature-rich IPTV with full mobility.
Starting with the 3GPP Release 8, E-UTRA is designed to provide a single evolution path for the GSM/EDGE, UMTS/HSPA, CDMA2000/EV-DO and TD-SCDMA radio interfaces, providing increases in data speeds, and spectral efficiency, and allowing the provision of more functionality.
EUTRAN consists only of eNodeBs on the network side. The eNodeB performs tasks similar to those performed by the nodeBs and RNC (radio network controller) together in UTRAN. The aim of this simplification is to reduce the latency of all radio interface operations. eNodeBs are connected to each other via the X2 interface, and they connect to the packet switched (PS) core network via the S1 interface. [3]
The EUTRAN protocol stack consists of: [3]
Interfacing layers to the EUTRAN protocol stack:
E-UTRA uses orthogonal frequency-division multiplexing (OFDM), multiple-input multiple-output (MIMO) antenna technology depending on the terminal category and can also use beamforming for the downlink to support more users, higher data rates and lower processing power required on each handset. [10]
In the uplink LTE uses both OFDMA and a precoded version of OFDM called Single-Carrier Frequency-Division Multiple Access (SC-FDMA) depending on the channel. This is to compensate for a drawback with normal OFDM, which has a very high peak-to-average power ratio (PAPR). High PAPR requires more expensive and inefficient power amplifiers with high requirements on linearity, which increases the cost of the terminal and drains the battery faster. For the uplink, in release 8 and 9 multi user MIMO / Spatial division multiple access (SDMA) is supported; release 10 introduces also SU-MIMO.
In both OFDM and SC-FDMA transmission modes a cyclic prefix is appended to the transmitted symbols. Two different lengths of the cyclic prefix are available to support different channel spreads due to the cell size and propagation environment. These are a normal cyclic prefix of 4.7 μs, and an extended cyclic prefix of 16.6 μs.
LTE supports both Frequency-division duplex (FDD) and Time-division duplex (TDD) modes. While FDD makes use of paired spectra for UL and DL transmission separated by a duplex frequency gap, TDD splits one frequency carrier into alternating time periods for transmission from the base station to the terminal and vice versa. Both modes have their own frame structure within LTE and these are aligned with each other meaning that similar hardware can be used in the base stations and terminals to allow for economy of scale. The TDD mode in LTE is aligned with TD-SCDMA as well allowing for coexistence. Single chipsets are available which support both TDD-LTE and FDD-LTE operating modes.
The LTE transmission is structured in the time domain in radio frames. Each of these radio frames is 10 ms long and consists of 10 sub frames of 1 ms each. For non-Multimedia Broadcast Multicast Service (MBMS) subframes, the OFDMA sub-carrier spacing in the frequency domain is 15 kHz. Twelve of these sub-carriers together allocated during a 0.5 ms timeslot are called a resource block. [11] A LTE terminal can be allocated, in the downlink or uplink, a minimum of 2 resources blocks during 1 subframe (1 ms). [12]
All L1 transport data is encoded using turbo coding and a contention-free quadratic permutation polynomial (QPP) turbo code internal interleaver. [13] L1 HARQ with 8 (FDD) or up to 15 (TDD) processes is used for the downlink and up to 8 processes for the UL
In the downlink there are several physical channels: [14]
And the following signals:
In the uplink there are three physical channels:
And the following signals:
3GPP Release 8 defines five LTE user equipment categories depending on maximum peak data rate and MIMO capabilities support. With 3GPP Release 10, which is referred to as LTE Advanced, three new categories have been introduced. Followed by four more with Release 11, two more with Release 14, and five more with Release 15. [2]
User equipment Category | Max. L1 data rate Downlink (Mbit/s) | Max. number of DL MIMO layers | Max. L1 data rate Uplink (Mbit/s) | 3GPP Release |
---|---|---|---|---|
NB1 | 0.68 | 1 | 1.0 | Rel 13 |
M1 | 1.0 | 1 | 1.0 | |
0 | 1.0 | 1 | 1.0 | Rel 12 |
1 | 10.3 | 1 | 5.2 | Rel 8 |
2 | 51.0 | 2 | 25.5 | |
3 | 102.0 | 2 | 51.0 | |
4 | 150.8 | 2 | 51.0 | |
5 | 299.6 | 4 | 75.4 | |
6 | 301.5 | 2 or 4 | 51.0 | Rel 10 |
7 | 301.5 | 2 or 4 | 102.0 | |
8 | 2,998.6 | 8 | 1,497.8 | |
9 | 452.2 | 2 or 4 | 51.0 | Rel 11 |
10 | 452.2 | 2 or 4 | 102.0 | |
11 | 603.0 | 2 or 4 | 51.0 | |
12 | 603.0 | 2 or 4 | 102.0 | |
13 | 391.7 | 2 or 4 | 150.8 | Rel 12 |
14 | 3,917 | 8 | 9,585 | |
15 | 750 | 2 or 4 | 226 | |
16 | 979 | 2 or 4 | 105 | |
17 | 25,065 | 8 | 2,119 | Rel 13 |
18 | 1,174 | 2 or 4 or 8 | 211 | |
19 | 1,566 | 2 or 4 or 8 | 13,563 | |
20 | 2,000 | 2 or 4 or 8 | 315 | Rel 14 |
21 | 1,400 | 2 or 4 | 300 | |
22 | 2,350 | 2 or 4 or 8 | 422 | Rel 15 |
23 | 2,700 | 2 or 4 or 8 | 528 | |
24 | 3,000 | 2 or 4 or 8 | 633 | |
25 | 3,200 | 2 or 4 or 8 | 739 | |
26 | 3,500 | 2 or 4 or 8 | 844 |
Note: Maximum data rates shown are for 20 MHz of channel bandwidth. Categories 6 and above include data rates from combining multiple 20 MHz channels. Maximum data rates will be lower if less bandwidth is utilized.
Note: These are L1 transport data rates not including the different protocol layers overhead. Depending on cell bandwidth, cell load (number of simultaneous users), network configuration, the performance of the user equipment used, propagation conditions, etc. practical data rates will vary.
Note: The 3.0 Gbit/s / 1.5 Gbit/s data rate specified as Category 8 is near the peak aggregate data rate for a base station sector. A more realistic maximum data rate for a single user is 1.2 Gbit/s (downlink) and 600 Mbit/s (uplink). [16] Nokia Siemens Networks has demonstrated downlink speeds of 1.4 Gbit/s using 100 MHz of aggregated spectrum. [17]
As the rest of the 3GPP standard parts E-UTRA is structured in releases.
All LTE releases have been designed so far keeping backward compatibility in mind. That is, a release 8 compliant terminal will work in a release 10 network, while release 10 terminals would be able to use its extra functionality.
General Packet Radio Service (GPRS), also called 2.5G, is a mobile data standard on the 2G cellular communication network's global system for mobile communications (GSM). Networks and mobile devices with GPRS started to roll out around the year 2001. At the time of introduction it offered for the first time seamless mobile data transmission using packet data for an "always-on" connection, providing improved Internet access for web, email, WAP services, and Multimedia Messaging Service (MMS).
The Universal Mobile Telecommunications System (UMTS) is a 3G mobile cellular system for networks based on the GSM standard. Developed and maintained by the 3GPP, UMTS is a component of the International Telecommunication Union IMT-2000 standard set and compares with the CDMA2000 standard set for networks based on the competing cdmaOne technology. UMTS uses wideband code-division multiple access (W-CDMA) radio access technology to offer greater spectral efficiency and bandwidth to mobile network operators.
4G is the fourth generation of broadband cellular network technology, succeeding 3G and preceding 5G. A 4G system must provide capabilities defined by the International Telecommunication Union (ITU) in IMT Advanced. Potential and current applications include amended mobile web access, IP telephony, gaming services, high-definition mobile TV, video conferencing, and 3D television.
The GPRS core network is the central part of the general packet radio service (GPRS) which allows 2G, 3G and WCDMA mobile networks to transmit Internet Protocol (IP) packets to external networks such as the Internet. The GPRS system is an integrated part of the GSM network switching subsystem.
Orthogonal frequency-division multiple access (OFDMA) is a multi-user version of the popular orthogonal frequency-division multiplexing (OFDM) digital modulation scheme. Multiple access is achieved in OFDMA by assigning subsets of subcarriers to individual users. This allows simultaneous low-data-rate transmission from several users.
RNSAP is a 3GPP signalling protocol responsible for communications between RNCs Radio Network Controllers defined in 3GPP specification TS 25.423. It is carried on the lur interface and provides functionality needed for soft handovers and SRNS relocation. It defines signalling between RNCs, including SRNC and DRNC.
SRNC | DRNC | IUR | RNSAP | RNSAP | | |
High Speed Packet Access (HSPA) is an amalgamation of two mobile protocols—High Speed Downlink Packet Access (HSDPA) and High Speed Uplink Packet Access (HSUPA)—that extends and improves the performance of existing 3G mobile telecommunication networks using the WCDMA protocols. A further-improved 3GPP standard called Evolved High Speed Packet Access was released late in 2008, with subsequent worldwide adoption beginning in 2010. The newer standard allows bit rates to reach as high as 337 Mbit/s in the downlink and 34 Mbit/s in the uplink; however, these speeds are rarely achieved in practice.
In GSM cellular networks, an absolute radio-frequency channel number (ARFCN) is a code that specifies a pair of physical radio carriers used for transmission and reception in a land mobile radio system, one for the uplink signal and one for the downlink signal. ARFCNs for GSM are defined in Specification 45.005 Section 2. There are also other variants of the ARFCN numbering scheme that are in use for other systems that are not GSM. One such example is the TETRA system that has 25 kHz channel spacing and uses different base frequencies for numbering.
The UMTS frequency bands are radio frequencies used by third generation (3G) wireless Universal Mobile Telecommunications System networks. They were allocated by delegates to the World Administrative Radio Conference (WARC-92) held in Málaga-Torremolinos, Spain between 3 February 1992 and 3 March 1992. Resolution 212 (Rev.WRC-97), adopted at the World Radiocommunication Conference held in Geneva, Switzerland in 1997, endorsed the bands specifically for the International Mobile Telecommunications-2000 (IMT-2000) specification by referring to S5.388, which states "The bands 1,885-2,025 MHz and 2,110-2,200 MHz are intended for use, on a worldwide basis, by administrations wishing to implement International Mobile Telecommunications 2000 (IMT-2000). Such use does not preclude the use of these bands by other services to which they are allocated. The bands should be made available for IMT-2000 in accordance with Resolution 212 ." To accommodate the reality that these initially defined bands were already in use in various regions of the world, the initial allocation has been amended multiple times to include other radio frequency bands.
Evolved High Speed Packet Access, HSPA+, HSPA (Plus) or HSPAP, is a technical standard for wireless broadband telecommunication. It is the second phase of HSPA which has been introduced in 3GPP release 7 and being further improved in later 3GPP releases. HSPA+ can achieve data rates of up to 42.2 Mbit/s. It introduces antenna array technologies such as beamforming and multiple-input multiple-output communications (MIMO). Beamforming focuses the transmitted power of an antenna in a beam toward the user's direction. MIMO uses multiple antennas on the sending and receiving side. Further releases of the standard have introduced dual carrier operation, i.e. the simultaneous use of two 5 MHz carriers. HSPA+ is an evolution of HSPA that upgrades the existing 3G network and provides a method for telecom operators to migrate towards 4G speeds that are more comparable to the initially available speeds of newer LTE networks without deploying a new radio interface. HSPA+ should not be confused with LTE though, which uses an air interface based on orthogonal frequency-division modulation and multiple access.
System Architecture Evolution (SAE) is the core network architecture of mobile communications protocol group 3GPP's LTE wireless communication standard.
LTE Advanced is a mobile communication standard and a major enhancement of the Long Term Evolution (LTE) standard. It was formally submitted as a candidate 4G to ITU-T in late 2009 as meeting the requirements of the IMT-Advanced standard, and was standardized by the 3rd Generation Partnership Project (3GPP) in March 2011 as 3GPP Release 10.
In telecommunications, long-term evolution (LTE) is a standard for wireless broadband communication for mobile devices and data terminals, based on the GSM/EDGE and UMTS/HSPA standards. It improves on those standards' capacity and speed by using a different radio interface and core network improvements. LTE is the upgrade path for carriers with both GSM/UMTS networks and CDMA2000 networks. Because LTE frequencies and bands differ from country to country, only multi-band phones can use LTE in all countries where it is supported.
International Mobile Telecommunications-Advanced are the requirements issued by the ITU Radiocommunication Sector (ITU-R) of the International Telecommunication Union (ITU) in 2008 for what is marketed as 4G mobile phone and Internet access service.
The UMTS channels are communication channels used by third generation (3G) wireless Universal Mobile Telecommunications System (UMTS) networks. UMTS channels can be divided into three levels:
E-UTRAN Node B, also known as Evolved Node B, is the element in E-UTRA of LTE that is the evolution of the element Node B in UTRA of UMTS. It is the hardware that is connected to the mobile phone network that communicates directly wirelessly with mobile handsets (UEs), like a base transceiver station (BTS) in GSM networks.
Long-Term Evolution (LTE) telecommunications networks use several frequency bands with associated bandwidths.
The Asia-Pacific Telecommunity (APT) band plan is a type of segmentation of the 612–806 MHz band formalized by the APT in 2022–2023 and 2008-2010 respectively and specially configured for the deployment of mobile broadband technologies. This segmentation exists in two variants, FDD and TDD, that have been standardized by the 3rd Generation Partnership Project (3GPP) and recommended by the International Telecommunication Union (ITU) as segmentations A5 and A6, respectively. The APT band plan has been designed to enable the most efficient use of available spectrum. Therefore, this plan divides the band into contiguous blocks of frequencies that are as large as possible taking account of the need to avoid interference with services in other frequency bands. As the result, the TDD option includes 100 MHz of continuous spectrum, while the FDD option comprises two large blocks, one of 45 MHz for uplink transmission in the lower part of the band and the other also of 45 MHz for downlink transmission in the upper part. As defined in the standard, both FDD and TDD schemes for the 700 MHz band include guard bands of 5 MHz and 3 MHz at their lower and upper edges, respectively. The FDD version also includes a centre gap of 10 MHz. The guard bands serve the purpose of mitigating interference with adjacent bands while the FDD centre gap is required to avoid interference between uplink and downlink transmissions. The two arrangements are shown graphically in figures 1 and 2.
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