What is LTE™?
Time : 2022-05-11

Long-Term Evolution (LTE) is a wireless broadcast communication standard for mobile devices and data ports based on GSM/EDGE and UMTS/HSPA technologies. The standard was developed by 3GPP (3rd Generation Partnership Project) and intended as a GSM/aims to provide a path for the upgrade of GSM/UMTS networks and CDMA2000 networks.


The following are the 3GPP-based advanced requirements for LTE:

  • Flexibility to use existing and new frequency bands
  • Simplified architecture, open interface
  • Allows reasonable port power consumption

When deploying a wireless communication system, spectrum resources need to be considered first. The two major international standardization organizations, 3GPP and ITU-T, both divide the LTE spectrum.


The International Telecommunication Union (ITU) conducted extensive research on frequency bands and in 2007 allocated candidate frequency bands for the deployment of fourth-generation communication systems. Relevant international and national standardization organizations have also carried out corresponding interference coexistence studies to prepare for the deployment of the fourth-generation communication system.

At the ITU-R WRC2007 conference, ITU identified 450-470MHz, 790-806MHz, 2300-2400MHz, a total of 136MHz for global IMT, and some countries can specify UHF (Ultra High Frequency) above 698MHz Frequency band, and 3400 – 3600MHz frequency band for IMT.


3GPP is one of the standardization organizations in the communication industry, formulating LTE/LTE-A related standards and applying to ITU for LTE/LTE-A as a candidate standard for IMT/IMT-A. After the operator obtains the frequency resource, it will put forward the standardization requirements of the radio frequency related equipment in 3GPP. 3GPP RAN4 is responsible for conducting research on radio frequency indicators of various frequency bands, and formulating and revising radio frequency standardization documents.


Today, we will introduce the 3GPP Spectrum Bands.

Currently, the frequency band requirements proposed by various operators are shown in Table 1. Among them, frequency bands 1 to 25 are LTE FDD frequency bands, and frequency bands 33 to 43 are TD-LTE frequency bands.


Uplink (UL) band BS reception, UE transmission Downlink (DL) frequency band BS transmission, UE reception Duplex
FUL_low~FUL_high FDL_low~FDL_high
1 1920MHz~1980MHz 2110MHz~2170MHz FDD
2 1850MHz~1910 MHz 1930MHz~1990MHz FDD
3 1710MHz~1785MHz 1805MHz~1880MHz FDD
4 1710MHz~1755MHz 2110MHz~2155MHz FDD
5 824MHz~849MHz 869MHz~894MHz FDD
6 830MHz~840 MHz 875MHz~885MHz FDD
7 2500MHz~2570MHz 2620MHz~2690MHz FDD
8 880MHz~915MHz 925MHz~960MHz FDD
9 1749.9MHz~1784.9MHz 1844.9MHz~1879.9MHz FDD
10 1710MHz~1770MHz 2110MHz~2170MHz FDD
11 1427.9MHz~1447.9MHz 1475.9MHz~1495.9MHz FDD
12 699MHz~716MHz 729MHz~746MHz FDD
13 777MHz~787MHz 746MHz~756MHz FDD
14 788MHz~798MHz 758MHz~768MHz FDD
15 reserve reserve FDD
16 reserve reserve FDD
17 704MHz~716MHz 734MHz~746MHz FDD
18 815MHz~830MHz 860MHz~875MHz FDD
19 830MHz~845MHz 875MHz~890MHz FDD
20 832MHz~862MHz 791MHz~821MHz FDD
21 1447.9MHz~1462.9MHz 1495.9MHz~1510.9MHz FDD
22 3410MHz~3490MHz 3510MHz~3590MHz FDD
23 2000MHz~2020MHz 2180MHz~2200MHz FDD
24 1626.5MHz~1660.5MHz 1525MHz~1559MHz FDD
25 1850MHz~1915MHz 1930MHz~1995MHz FDD
33 1900MHz~1920MHz 1900MHz~1920MHz TDD
34 2010MHz~2025MHz 2010MHz~2025MHz TDD
35 1850MHz~1910MHz 1850MHz~1910MHz TDD
36 1930MHz~1990MHz 1930MHz~1990MHz TDD
37 1910MHz~1930MHz 1910MHz~1930MHz TDD
38 2570MHz~2620MHz 2570MHz~2620MHz TDD
39 1880MHz~1920MHz 1880MHz~1920MHz TDD
40 2300MHz~2400MHz 2300MHz~2400MHz TDD
41 2496MHz~2690MHz 2496MHz~2690MHz TDD
42 3400MHz~3600MHz 3400MHz~3600MHz TDD
43 3600MHz~3800MHz 3600MHz~3800MHz TDD
Note 1:Band 6 is not applicable

LTE concept

The LTE system introduces key transmission technologies such as OFDM (Orthogonal Frequency Division Multiplexing) and MIMO (Multi-Input & Multi-Output), which significantly increases the spectral efficiency and data transmission rate (20M Bandwidth 2X2MIMO In the case of 64QAM, the theoretical maximum downlink transmission rate is 201Mbps, and it is about 140Mbps after deducting signaling overhead.

However, according to the actual networking and terminal capability limitations, it is generally considered that the downlink peak rate is 100Mbps, and the uplink is 50Mbps), and supports multiple various bandwidth allocations: 1.4MHz, 3MHz, 5MHz, 10MHz, 15MHz and 20MHz, etc., and support the global mainstream 2G/3G frequency bands and some new frequency bands, so the spectrum allocation is more flexible, and the system capacity and coverage are also significantly improved.


The network architecture of the LTE system is flatter and simpler, which reduces the network nodes and the complexity of systems, thereby reducing system delay and the cost of network deployment and maintenance.


The LTE system supports interoperability with other 3GPP systems.

There are two types of LTE systems: FDD-LTE and TDD-LTE, namely frequency division duplex LTE system and time division duplex LTE system. The main difference between the two technologies lies in the physical layer of the air interface (such as frame structure, time division design, synchronization etc.).

The uplink and downlink transmission of the FDD-LTE system uses a pair of symmetrical frequency bands to receive and transmit data, while the uplink and downlink of the TDD-LTE system use the same frequency band to transmit on different time slots. Compared with the FDD duplex mode, TDD has higher spectrum utilization.

LTE system structure

LTE adopts a single-layer structure composed of eNBs, which is beneficial to simplify the network and reduce the delay, and realize the requirements of low latency, low complexity and low cost. Compared with 3G access network, LTE reduces RNC nodes. Nominally LTE is the evolution of 3G, but in fact it has made revolutionary changes to the entire system architecture of 3GPP, gradually approaching the typical IP broadband network structure.

The LTE architecture is also called the E-UTRAN architecture. E-UTRAN is mainly composed of eNBs. Compared with UTRAN network, eNB not only has the function of Node B, but also can complete most functions of RNC, including physical layer, MAC layer, RRC, scheduling, access control, bearer control, access mobility management and Inter-cell RRM etc.