VoLTE and IMS and 5G/LTE Data Throughput: From practical analysis to Big Tech technical interviews

This is a course to learn VoLTE and IMS call processing and 5G/LTE data throughput from a practical perspective based on 25 years of specialized technology and analysis experience in communication and mobile terminals. It doesn't stop by memorizing the name of the message, but it also links and explains how the procedure continues and what items to check first when a problem occurs.

VoLTE and IMS call processing, message order, and delivery path are analyzed together

VoLTE and IMS look at the roles of terminals and network systems, protocol layers, and transmission paths for SIP and media. Check IMS Registration, Authentication and Secure Connections, Registration Renewal and Cancellation, and Outbound and Incoming Call Settings in that order. By analyzing the SIP header, response code, SDP address and port, and the relationship between codec and RTP together, we learn that even for the same message, the confirmation items vary depending on the stage of occurrence and the type of request.

From OFDM to theoretical throughput values for terminal categories and MIMO

Data Throughput first explains the basic structure of OFDM and explores how bandwidth, resource blocks, MCS, and MIMO relate to the amount of data that can be transferred. Compare the LTE UE Category's support limits and actual settings, and check with calculations and graphs why performance varies depending on currently allocated resources and the actual number of layers, even with high support specifications.

The frequently checked field bandwidth, assigned PRB, MCS, DL·UL MIMO, BLER, and CQI are organized into a single analysis flow. Learn how to check the size and activity status of transmission resources, actual rank, retransmission, time resources, and test conditions together without judging performance based on high CQI or high MCS alone. Significant differences between CA and Band Combination, US operator Band, and 5G/LTE are also linked to performance analysis.

Check the difference between theoretical values and actual performance with comparison tests

When the theoretical value and actual performance are different, the comparison criteria and current settings are adjusted first. We will take a step-by-step look at what the theoretical conditions are, what conditions have changed now, and what values should be changed in the next comparison test. The goal of this course is to distinguish between the device's maximum supported performance and current operation, and to create a judgment order that can explain measured values.

Linking practical analysis to Big Tech technical interview questions and answers

It also includes practical technical interview questions and answers for those preparing for telecommunication, modem, and cellular-related positions at Big Tech such as Apple, Google, and Meta. We will summarize the reasons why the speed varies at the same bandwidth, the difference between DL 4×4 support and actual rank, and situations where throughput is low even with high CQI and MCS, and practice answers with conditions and confirmation items. It is a structure that links practical analysis covered in the course to technical interview answers.

I will explain based on 25 years of practical experience in communication and mobile terminals

Lecturer Kim Ki-hong performed HW/SW verification and commercialization of mobile terminals at KT, network connectivity verification of new devices and services at AT&T, 5G, IMS, VoIP, and E911 tests at Keysight Technologies, and coordination of terminal and service quality and technical issues for US telecommunications carriers at Samsung Electronics America.

Learn with pictures, messages, and calculations in 12 lessons

Lectures are conducted with direct Korean recordings, system structure diagrams, call processing flow, message comparison, and calculation diagrams. Since key terms and corresponding positions in the picture are emphasized according to the time of explanation, you can follow the procedure and analysis points together. You can first understand call processing in VoLTE and IMS according to the order of the 12 lessons, and then learn the theoretical value and actual performance analysis of data throughput.

Lesson 1-6 | From VoLTE and IMS Registration to Abnormal Call Handling

It covers IMS registration, authentication/security, call settings, SDP·Bearer, CodeC·RTP, session/additional service/SRVCC, emergency, and abnormal call processing in that order.

Lesson 7-12 | From OFDM basics to 5G/LTE performance diagnosis

We will continue OFDM, LTE UE category, MIMO, LTE resource calculation, CA·band combination, US operator band, NR throughput and performance degradation comparison tests, and NSA/SA integrated analysis.

Recommended for people like this

It is suitable for those who are in charge of communication and mobile terminal development, verification, and performance analysis, or are preparing technical interviews for related jobs. It is helpful to know the basic structure and communication terms of LTE and 5G.

You can learn with PPTX textbooks, messages, and numerical analysis provided without separate measuring equipment or paid analysis tools. The technical terms and standard field names are kept in the original English text, and the instructor explains them directly in Korean.

VoLTE and IMS and 5G/LTE Data Throughput: Practical Analysis ~ Big Tech Technical Interview

VoLTE and IMS and 5G/LTE Data Throughput: Practical Analysis ~ Big Tech Technical Interview