As mobile networks migrate to 5G, massive MIMO will be a fundamental underlying technology helping to realize the predicted 100X capacity when compared to today’s LTE-A and LTE-A Pro technologies. Massive MIMO will be required in the low-, mid-, and high-band spectrum. In the high band, or millimeter wave (mmWave) spectrum massive MIMO will be used in beamforming mode to overcome the non-line-of-sight (NLOS) limitations at these frequencies.
Massive MIMO deploys large numbers of antennas in the base station – more than there are UEs in the sector. These “excess” antennas permit the RAN to narrowly focus radiated energy only towards those UEs which require it. The effect of this is to dramatically increase the spectral efficiency allowing the sector throughput to increase and the MNO to maximize the use of network resources in the RAN
In addition to the spectral efficiency gain from massive MIMO other benefits include the ability to use inexpensive low-power components since the total radiated power in the sector is now shared among many antennas. Massive MIMO also enables a reduction in the total RF power of the sector leading to TCO savings for the MNO and potentially raising the prospect of solar or wind powered base stations. Massive MIMO also enables a large reduction in the latency of the air interface since the radiated energy is not subject to fading dips in the signal strength due to channel hardening.