3.1 - LTE 4G ARCHITECTURE BASICS - INTRODUCTION

Summary

This video introduces the LTE architecture series, highlighting the major reasons for LTE's development. It discusses the rapid growth in mobile subscribers from 2000 to 2010, leading to network congestion and the need for increased capacity. The video covers the evolution from 3G to LTE, including the redesign of the air interface with OFDM to reduce multipath fading and improve bandwidth utilization. It also touches on the shift to an all-IP core network for simplified design and the introduction of VoLTE. Lastly, it provides insights into the User Equipment, including the SIM card's role in LTE and the distinction between USIM and ISIM modules.

Takeaways

• 📱 The rapid growth in mobile subscribers from 500 million to 4.5 billion between 2000 and 2010, driven by devices like the iPhone and Android smartphones, led to network congestion and a need for increased network capacity.
• 🚀 To address congestion, 3GPP redesigned the Radio Access Network (RAN) and Core Network, leading to the development of LTE.
• 📶 LTE introduced OFDM technology to combat multipath fading and improve data rates, offering more efficient bandwidth utilization with support for bandwidths from 1.25 MHz to 20 MHz and beyond through Carrier Aggregation.
• 🌐 The shift to an all-IP based core network in LTE simplified network design and implementation, replacing the traditional circuit-switched core used for voice and SMS in 2G/3G with Voice over LTE (VoLTE).
• 🔄 LTE's all-IP approach, including for backhaul connections, offered significant simplification over previous technologies that used E-1, ATM, and frame relay links.
• 🔑 The Universal Integrated Circuit Card (UICC), or SIM card, in LTE can run applications like the Universal Subscriber Identity Module (USIM) for user-specific data and the IP Multimedia Private Identity (IMPI) module for secure VoLTE calls.
• 🏗️ The LTE architecture was designed with the Internet of Things (IoT) in mind, prioritizing lower latency and faster backhaul to support the expected 28 billion connected devices by 2021.
• 📡 The User Equipment (UE) in LTE, similar to UMTS and GSM, consists of Mobile Termination (MT) for communication functions, Terminal Equipment (TE) for data streams, and a UICC that can include a USIM or ISIM.
• 🛠️ LTE's air interface and network design improvements were necessary to meet the demands of increased data usage, higher quality voice services, and the integration of IoT devices.
• ⏳ LTE's maximum allowed delay ranges from 50ms to 300ms depending on Quality of Service (QoS), which is crucial for latency-sensitive IoT applications.

Q & A

What was the major reason for the development of LTE?

The major reason for the development of LTE was the need for increased network capacity due to the rapid growth in mobile subscribers and data usage, which led to network congestion around 2010.

How did the introduction of flat rate charging schemes affect mobile networks?

The introduction of flat rate charging schemes, which allowed unlimited data downloads, resulted in network congestion as users consumed more data.

What was the limitation of UMTS or 3G technology that necessitated the redesign of LTE?

UMTS faced design limitations, such as the interface with a carrier bandwidth of 5MHz in WCDMA, which did not scale well in practice and led to the need for a redesign of the RAN and core parts.

What is OFDM and how does it improve LTE performance?

OFDM (Orthogonal Frequency Division Multiplexing) is a technique where data is transmitted over many narrow bands of 180kHz instead of spreading a signal over the entire band. This reduces multipath fading and allows for more efficient bandwidth utilization.

How does LTE's bandwidth flexibility compare to UMTS?

LTE offers more bandwidth flexibility than UMTS, with bandwidth ranging from 1.25MHz to up to 20MHz, and the ability to further increase this through carrier aggregation.

What is the significance of the all-IP based core network in LTE?

The all-IP based core network in LTE simplifies the design and implementation of the air interface, radio network, and core. It also allows for the adoption of VoLTE, which is cheaper and more versatile than traditional circuit-switched voice calls.

Why is latency more important than bandwidth for IoT devices?

For IoT devices, latency is more important than bandwidth because these devices often require real-time or near-real-time communication, which is sensitive to delays in data transmission.

What is the maximum allowed delay in LTE for different QoS?

In LTE, the maximum allowed delay ranges from 50ms to 300ms depending on the Quality of Service (QoS) requirements.

How does the use of IP-based interfaces in LTE simplify network operations compared to earlier technologies?

Using IP-based interfaces in LTE simplifies network operations by replacing earlier technologies that were based on E-1, ATM, and frame relay links, which were narrowband, expensive, and more complex.

What is the role of the Universal Integrated Circuit Card (UICC) in LTE User Equipment?

The UICC, also known as the SIM card, plays a crucial role in LTE User Equipment by storing user-specific data, including the user's phone number, home network identity, and security keys. It can also run applications like the USIM for LTE-specific functionalities.

What are the main components of the Mobile Equipment (ME) in LTE User Equipment?

The main components of the Mobile Equipment (ME) in LTE User Equipment include Mobile Termination (MT), Terminal Equipment (TE), and the Universal Integrated Circuit Card (UICC), which encompasses the SIM card and its applications.