E-UTRA


E-UTRA is the air interface of 3rd Generation Partnership Project Long Term Evolution upgrade path for mobile networks. It is an acronym for Evolved Universal Mobile Telecommunications System Terrestrial Radio Access, also referred to as the 3GPP work item on the Long Term Evolution also known as the Evolved Universal Terrestrial Radio Access in early drafts of the 3GPP LTE specification. E-UTRAN is the initialism of Evolved UMTS Terrestrial Radio Access Network and is the combination of E-UTRA, user equipment, and E-UTRAN Node B or Evolved Node B.
It is a radio access network which is referred to under the name EUTRAN standard meant to be a replacement of the UMTS and HSDPA/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 OFDMA radio-access for the downlink and SC-FDMA on the uplink. Trials started in 2008.

Features

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 and core network evolution 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.

Architecture

EUTRAN consists only of enodeBs on the network side. The enodeB performs tasks similar to those performed by the nodeBs and RNC 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 core network via the S1 interface.

EUTRAN protocol stack

The EUTRAN protocol stack consist of:
Interfacing layers to the EUTRAN protocol stack:
E-UTRA uses orthogonal frequency-division multiplexing, multiple-input multiple-output antenna technology depending on the terminal category and can use as well beamforming for the downlink to support more users, higher data rates and lower processing power required on each handset.
In the uplink LTE uses both OFDMA and a precoded version of OFDM called Single-Carrier Frequency-Division Multiple Access depending on the channel. This is to compensate for a drawback with normal OFDM, which has a very high peak-to-average power ratio. 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 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 16.6μs.
s, 0.5 ms timeslot.
LTE supports both Frequency-division duplex and Time-division duplex 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-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. A LTE terminal can be allocated, in the downlink or uplink, a minimum of 2 resources blocks during 1 subframe.
All L1 transport data is encoded using turbo coding and a contention-free quadratic permutation polynomial turbo code internal interleaver. L1 HARQ with 8 or up to 15 processes is used for the downlink and up to 8 processes for the UL

EUTRAN physical channels and signals

Downlink (DL)

In the downlink there are several physical channels:
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, and four more with 3GPP Release 11. and two more with 3GPP Release 14.
User
equipment
Category		Max. L1
data rate
Downlink
Max. number
of DL MIMO
layers		Max. L1
data rate
Uplink
3GPP Release
NB10.6811.0Rel 13
M11.011.0Rel 13
01.011.0Rel 12
110.315.2Rel 8
251.0225.5Rel 8
3102.0251.0Rel 8
4150.8251.0Rel 8
5299.6475.4Rel 8
6301.52 or 451.0Rel 10
7301.52 or 4102.0Rel 10
82,998.681,497.8Rel 10
9452.22 or 451.0Rel 11
10452.22 or 4102.0Rel 11
11603.02 or 451.0Rel 11
12603.02 or 4102.0Rel 11
13391.72 or 4150.8Rel 12
14391.789,585Rel 12
157502 or 4226Rel 12
169792 or 4n/aRel 12
1725,0658n/aRel 13
181,1742 or 4 or 8n/aRel 13
191,5662 or 4 or 8n/aRel 13
202,0002 or 4 or 8315Rel 14
211,4002 or 4300Rel 14

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, 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 and 600 Mbit/s. Nokia Siemens Networks has demonstrated downlink speeds of 1.4 Gbit/s using 100 MHz of aggregated spectrum.

EUTRAN releases

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.

Frequency bands and channel bandwidths

Deployments by region

Technology demos