The absolute calibration of an antenna array aims at estimating the phase errors introduced by the radio frequency (RF) chains of a communication device. Compensating these errors is relevant, especially for the initial access of 5G cellular systems operating with mmWaves, i.e., when the base station (BS) focuses its reception towards specific directions to discover mobile terminals (MTs) that just entered the cell. We first collect estimates of many MT-BS channels, in order to estimate the channel autocorrelation matrix, from which phase errors on each antenna are estimated. While the distribution of the angles of arrival (AoA) is assumed known in most of the literature, thus simplifying the phase estimation, we consider two more realistic cases: 1) AoA's are uniformly distributed in a sector of unknown size; or 2) no prior knowledge on AoA's distribution is available. We either estimate the angles of radius delimiting the sector (case 1), or the entire AoA's distribution (case 2). For case 2) we also assess the estimation error when using an array with a small number of antennas.
Calibration of mmWave Antenna Arrays for Initial Access in Massive MIMO 5G Cellular Networks
GLAMOCIC, DEMIR;Tomasin S.
2019
Abstract
The absolute calibration of an antenna array aims at estimating the phase errors introduced by the radio frequency (RF) chains of a communication device. Compensating these errors is relevant, especially for the initial access of 5G cellular systems operating with mmWaves, i.e., when the base station (BS) focuses its reception towards specific directions to discover mobile terminals (MTs) that just entered the cell. We first collect estimates of many MT-BS channels, in order to estimate the channel autocorrelation matrix, from which phase errors on each antenna are estimated. While the distribution of the angles of arrival (AoA) is assumed known in most of the literature, thus simplifying the phase estimation, we consider two more realistic cases: 1) AoA's are uniformly distributed in a sector of unknown size; or 2) no prior knowledge on AoA's distribution is available. We either estimate the angles of radius delimiting the sector (case 1), or the entire AoA's distribution (case 2). For case 2) we also assess the estimation error when using an array with a small number of antennas.
Pubblicazioni consigliate
I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
