Lens Antenna Subarrays in mmWave Hybrid MIMO Systems

Data rate and energy efficiency performance of mmWave wireless communication systems consisting of a new lens antenna subarray (LAS) based hybrid multiple input multiple output (MIMO) architecture is investigated. The LAS architecture degenerates into traditional hybrid MIMO architecture (TA) or single lens antenna array architecture (SLA) when the lens diameter of the subarray is reduced or enlarged, respectively. It is shown that under mmWave channel scattering conditions, LAS architecture operates with a data rate approaching that of TA while significantly exceeding the data rate of the SLA. Due to the reduced hardware complexity and power consumption, LAS architectures operate with a significantly improved energy efficiency. In an example system consisting of 64 and 16 transmitter and receiver antennas with 2 RF chains, it is shown that the LAS architecture operates with 2\times energy efficiency and 98% spectrum efficiency. In a larger hybrid MIMO antenna systems, LAS architecture is expected to benefit even more.