Providing 10 Gbit/s in Downlink to a Mobile Terminal with Practical Array Design Beamforming Aspects by Using Orthogonal MIMO Beams

Orthogonal MIMO beam directions for spatially multiplexed data streams (SMDSs) and terminal array limitations with a steering angle are studied in this paper. As delivering SMDS for large distances is challenging, the research work studies a short-range indoor environment with line-of-sight (LOS) & non-LOS MIMO channel models for time-division duplex orthogonal frequency-division multiplexing 5G system. Radio frequency (RF) modelling method is utilized for link budget analysis where digital signal processing is abstracted to the minimum signal-to-noise ratio (SNR) requirements and RF system SNR described based on transmitter and receiver performance related to output and input power levels. By limiting a terminal to six array elements at 10 GHz, it is shown that channel dynamic range, e.g., in LOS can even exceed some 45 dB between the best and worst eigen value-based beams. For some users, beam angle-of-arrivals were observed to vary even 100 degrees. Mobile array steering range was shown to cause fundamental restrictions to capture SMDSs from wide beam angles with sufficient array gain. Achieved user data rates and power consumption are demonstrated at the end of this paper.