Millimetre Wave Propagation Reverse Measurements for 5G Urban Micro Scenario

The double-direction channel describes the angular pairing of rays connecting a base station (BS) to its user terminal (UE). This paper presents double-directional experimental measurements for an Urban Micro-cellular (UMi) campus environment at millimetre wave frequencies. Results showed that multiple Angles of Departure (AoD) from a given UE position often result in few (often one) Angles of Arrival (AoA) at the BS. Similarly different UE locations can often share a common angle of arrival at the BS. Three AoA's covered all the dominant transmissions from 9 of the 11 UE sites evaluated in the test location. Such situations can limit spectral efficiency by reducing both MIMO and spatial division multiple access performance.