Researchers in Japan have built a 28 GHz mmwave phased-array 256 MIMO transceiver that supports low latency switching for more reliable 5G communications in the Internet of Things (IoT) .
The joint team at Tokyo Institute of Technology (Tokyo Tech) and NEC developed the transceiver on a 65nm process with fast beam switching between 256 beams leakage cancellation mechanisms to reduce the noise and power consumption.
Millimetre wave designs at 28 GHz and above for 5G can offer data rates over 10 Gbit/s with multiple-in-multiple-out (MIMO) technology, and this needs large scale phased-array transceivers. While MIMO systems boost spectral performance, large-scale phased-array systems face several challenges such as increased power dissipation and implementation costs.
One such critical challenge is latency caused by beam switching time. Beam switching is an important feature that enables the selection of the most optimal beam for each terminal.
The design highlighted at the 2021 VLSI Symposium uses dual-polarized operation with data transmitted simultaneously through horizontal and vertical-polarized waves. However, one issue with these systems is cross-polarization leakage, which results in signal degradation.