  Asymmetry is unquestionably an important characteristic of the wireless
propagation channel, which needs to be accurately modeled for wireless and
mobile communications, 5G networks, and associated applications such as
indoor/outdoor localization. This paper reports on the potential causes of
propagation asymmetry. Practical channel measurements at Khalifa University
premises proved that wireless channels are asymmetric in realistic scenarios.
Some important conclusions and recommendation are also summarized.
