研究目的

Investigating the behaviour of a 28 GHz Massive MIMO 5G new radio (NR) test system in a semi-open urban environment to demonstrate the potential of beam management in terms of performance both for single-user MIMO (SU-MIMO) and for MU-MIMO.

研究成果

The paper demonstrated the behaviour of a 28 GHz 5G new radio (NR) test system in a semi-open urban environment operating with 400 MHz BW. Single-User MIMO (SU-MIMO) performance was evaluated in terms of coverage and propagation. The importance of reflections was demonstrated. For the considered test area reflections improved the channel conditions and gave a relatively high abundance of rank 3 and 4. The peak throughput was 6.2 Gbps in LOS corresponding to 15.5 bps/Hz. The propagation around a corner was characterized and it was found that a combination of available models matches the measured behaviour reasonably well. Beam forming is a key enabler for achieving good multi-user MIMO (MU-MIMO) performance thanks to reduced interference between the users due to narrow and well-focused beams. In the present paper significant single-cell MU-MIMO gains – for the total system DL throughput often more than 60% in median gain – were demonstrated compared to SU-MIMO operation with Round-Robin resource sharing.

研究不足

The test system supports up to 800 MHz bandwidth (BW), but only 400 MHz BW was utilized in the conducted tests due to limited spectrum permit at 28 GHz in the outdoor test area.