Low-cost Group-selected Structure in Multi-user Millimeter Wave Systems with Lens Antenna Array

Lens antenna array (LAA) has been widely studied to reduce the number of RF chains in millimeter wave communication systems. It is a critical issue to make a tradeoff between the hardware cost and the ability to cope with the power leakage problem. In this letter, we propose a low-cost group-selected structure without necessitating the high-cost phase shifters. More specifically, the antennas are divided into several groups equally at first. Then each radio frequency (RF) chain selects one antenna group via a switch network and the signal from this RF chain is transmitted through the antennas in the selected group with its power equally divided. Results show that the proposed structure performs similarly to the state-of-the-art structures intended for power leakage reduction with much lower hardware cost and training complexity requirements.