  Location fingerprint (LF) has been widely applied in indoor positioning.
However, the existing studies on LF mostly focus on the fingerprint of WiFi
below 6 GHz, bluetooth, ultra wideband (UWB), etc. The LF with millimeter-wave
(mmWave) was rarely addressed. Since mmWave has the characteristics of narrow
beam, fast signal attenuation and wide bandwidth, etc., the positioning error
can be reduced. In this paper, an LF positioning method with mmWave is
proposed, which is named as DoA-LF. Besides received signal strength indicator
(RSSI) of access points (APs), the fingerprint database contains direction of
arrival (DoA) information of APs, which is obtained via DoA estimation. Then
the impact of the number of APs, the interval of reference points (RPs), the
channel model of mmWave and the error of DoA estimation algorithm on
positioning error is analyzed with Cramer-Rao lower bound (CRLB). Finally, the
proposed DoA-LF algorithm with mmWave is verified through simulations. The
simulation results have proved that mmWave can reduce the positioning error due
to the fact that mmWave has larger path loss exponent and smaller variance of
shadow fading compared with low frequency signals. Besides, accurate DoA
estimation can reduce the positioning error.
