LTE Frequently Asked Questions
LTE stands for Long-Term Evolution, which is a wireless communication standard for high-speed data and voice services for mobile devices.
The goal of LTE is to provide faster data speeds, higher spectral efficiency, lower latency, and better coverage compared to previous mobile communication standards.
LTE can offer data speeds of up to 100 Mbps for downloads and up to 50 Mbps for uploads, depending on network conditions and device capabilities.
LTE Advanced is an enhancement to the original LTE standard, providing even faster data speeds, higher spectral efficiency, and other advanced features such as carrier aggregation, enhanced multi-antenna techniques, and more.
LTE architecture consists of several network elements, including the Evolved Universal Terrestrial Radio Access Network (EUTRAN), Evolved Packet Core (EPC), and User Equipment (UE).
EUTRAN is the radio access network in LTE, consisting of eNodeBs that communicate with UEs over the air interface using LTE-specific air interfaces.
LTE Interfaces are the communication interfaces between various network elements in the LTE architecture, including S1, X2, and Uu interfaces.
LTE Network elements are the functional entities within the LTE architecture, including eNodeBs, MMEs, SGWs, PGWs, and HSSs.
LTE protocols and specifications are the technical standards that define the behavior of various network elements and interfaces in the LTE architecture, including radio access protocols, core network protocols, and more.
VoLGA (Voice over LTE via Generic Access) is a method for providing voice services over LTE networks using a separate network for voice, such as 2G or 3G networks.
CS Fallback is a mechanism for providing voice services over legacy 2G or 3G networks when LTE networks do not support voice services.
LTE security uses various mechanisms, including encryption, authentication, and key agreement protocols, to protect user data and network resources from unauthorized access and attacks.
IMS is a standardized architecture for delivering multimedia services over IP networks, including voice, video, and messaging services.
Measurements in LTE are used to determine network performance and optimize network resources, including measuring signal strength, interference, and other metrics.
Automatic Neighbour Relation (ANR) is a feature in LTE networks that automatically creates and updates neighbour cell lists, allowing for efficient handover and improved network performance.
Intra E-UTRAN Handover is performed when a UE moves from one cell to another within the same EUTRAN, allowing for seamless connectivity and improved network performance.
Policy control and charging in LTE involve defining and enforcing policies for network resource usage and charging users for network access and services.
SON (Self-Organizing Network) is a feature in LTE networks that allows for automatic network optimization and configuration, improving network performance and efficiency.
Network sharing in LTE involves multiple operators sharing network resources, such as spectrum and infrastructure, to reduce costs and improve network coverage.
Timing Advance (TA) is a mechanism used in LTE to ensure proper synchronization between the User Equipment (UE) and the base station (eNodeB). The TA value determines the distance between the UE and the eNodeB, and is used to adjust the transmission timing of the UE. The eNodeB sends a downlink signal to the UE with a known timing, and the UE calculates the time difference between the received signal and the expected timing. The UE then sends a TA command to the eNodeB to adjust the transmission timing of the uplink signal.
LTE UE positioning in E-UTRAN uses various techniques such as Observed Time Difference of Arrival (OTDOA), Enhanced Cell ID (E-CID), and Assisted Global Navigation Satellite System (A-GNSS) to determine the location of a UE. OTDOA uses the difference in arrival time of signals from different eNodeBs to calculate the UE's location. E-CID uses cell ID information to estimate the UE's location. A-GNSS uses satellite signals to provide location information that is used in combination with other positioning techniques.
As of September 2021, more than 700 operators in over 210 countries have committed to LTE, according to the Global Mobile Suppliers Association (GSA).
Single Radio Voice Call Continuity (SRVCC) is a feature in LTE that enables seamless handover of voice calls from LTE to 2G/3G networks without interruption. SRVCC allows voice calls to be transmitted over both LTE and circuit-switched networks, enabling operators to support voice services while transitioning to LTE.
Location Service (LCS) in LTE network enables location-based services such as emergency calling, location-based advertising, and geo-fencing. The location of the UE is determined using various positioning techniques such as OTDOA, E-CID, and A-GNSS. The location information is then provided to the LCS client, which is responsible for providing location-based services to the user.
Lawful Interception (LI) in LTE Evolved Packet System (EPS) is a mechanism that allows authorized authorities to intercept and monitor communication traffic in the network for lawful purposes such as national security and criminal investigations. The LI function is implemented in the LTE network elements such as eNodeBs and the Mobility Management Entity (MME). When a request for interception is received, the network elements intercept the relevant communication traffic and forward it to the authorized authorities.
Carrier aggregation is a feature in LTE-Advanced that enables the aggregation of multiple frequency bands to increase the bandwidth available for data transmission. This enables higher data rates and improved network performance. Carrier aggregation allows the network to use non-contiguous spectrum and different frequency bands to provide a larger bandwidth for data transmission.
For example, if a mobile network operator has two separate frequency bands, each with a bandwidth of 10 MHz, carrier aggregation can be used to combine them into a single 20 MHz channel. This wider channel can then be used to provide higher data transfer rates for users with compatible devices.
Carrier aggregation is a key feature in LTE-Advanced, and it is widely used in modern 4G LTE networks to improve network performance and capacity.
Relay Node is a feature in LTE-Advanced that enables the deployment of low-power nodes that can relay traffic between the UE and the eNodeB, extending the coverage and improving network performance. Relaying works by using a Relay Node to receive and re-transmit signals between the UE and the eNodeB, effectively extending the range of the network. Relaying can be used in both the uplink and downlink directions and can be deployed in various network topologies to improve coverage and performance.