TY - UNPB
T1 - FDD Massive MIMO - Antenna Duplex Pattern an-Reciprocity
T2 - A Missing Brick
AU - Eggers, Patrick Claus Friedrich
AU - Zhekov, Stanislav Stefanov
PY - 2020
Y1 - 2020
N2 - Obtaining down link (DL) channel state information (CSI) at the base station (BS) is challenging for frequencydivision-duplex (FDD) massive MIMO (MM) systems. Considerable overhead is required for DL training and feedback. Instead studies often assume highly correlated average spatial signal signatures (i.e. directional clusters) between FDD duplex links. These assumptions, however, only represent use of antennas with the same radiation pattern over the duplex band, leading to illumination of the same cluster. In this paper, we investigate pattern reciprocity, over the duplex band, for practical user handsets. We first show how a population of measured contemporary phones exhibits noticeable duplex pattern divergence. We then show measured complex pattern duplex divergence of a mock-up phone, where depolarization comes on top of gain differences. Thus we reveal a significant but overlooked brick in DL CSI assessment for FDD MM operation. Namely, in order for the FDD MM performance studies to be realistic, practical user handsets have to be considered.
AB - Obtaining down link (DL) channel state information (CSI) at the base station (BS) is challenging for frequencydivision-duplex (FDD) massive MIMO (MM) systems. Considerable overhead is required for DL training and feedback. Instead studies often assume highly correlated average spatial signal signatures (i.e. directional clusters) between FDD duplex links. These assumptions, however, only represent use of antennas with the same radiation pattern over the duplex band, leading to illumination of the same cluster. In this paper, we investigate pattern reciprocity, over the duplex band, for practical user handsets. We first show how a population of measured contemporary phones exhibits noticeable duplex pattern divergence. We then show measured complex pattern duplex divergence of a mock-up phone, where depolarization comes on top of gain differences. Thus we reveal a significant but overlooked brick in DL CSI assessment for FDD MM operation. Namely, in order for the FDD MM performance studies to be realistic, practical user handsets have to be considered.
U2 - 10.48550/arXiv.2011.07492
DO - 10.48550/arXiv.2011.07492
M3 - Preprint
BT - FDD Massive MIMO - Antenna Duplex Pattern an-Reciprocity
PB - arXiv
ER -