LTE Advanced is using OFDMA. What is the difference between OFDM and

OFDMA and what is in common? The expectation here is that because of time limitation you

answer primarily using 4-5 diagrams.

When answering, you should follow as the guiding principle: Everything Should Be Made as

Simple as Possible, But Not Simpler which is credited to Albert Einstein.

What problems related to channel conditions does OFDM solve? What are the advantages in

terms of bandwidth utilization when working with OFDMA as opposed to assigning all subcarriers to the only user accessing the channel at any given time in conventional OFDM. In the latter case you would have to consider different channel frequency responses for two users

accessing the channel in two different time slots.

FYI: Most modern Comm Systems are adopting OFDM and OFDMA. However OFDM is based

on single carrier QAM and this is why we were reviewing the basic QAM concepts in this

course. As an example DOCSIS 3.1 physical layer specifications adapt the use of OFDM in the

downstream channels and OFDMA in the upstream channels.