I first received an email informed me that I was selected for a phone interview whine 3-5 days. Next, I received an email from the interviewer. We scheduled the interview time and day and he called me on that time. Question were all technical. Among them: 1- My current research and job 2- What is channel coherence time and bandwidth 3- How to perform maximum likelihood detection of QAM over AWGN and fading channel 4- Questions on detection of MIMO-OFDM? Difference between MMSE and MLE? which one is better? and which one is optimum? How they perform In high SNR and low SNR? 5- Questions on fixed-point implementation 6-