Channel Estimation for Multicell Multiuser Massive MIMO Uplink Over Rician Fading Channels

Abstract

Abstract-Pilot contamination (PC) is a major problem in massive multiple-input multiple-output (MIMO) systems. This paper proposes a novel channel estimation scheme for such a system in Rician fading channels. First, the possible angle of arrivals (AOAs) of users served by a base station (BS) are derived by exploiting the channel statistical information, assuming a traditional pilot structure, where the pilots for the same-cell users are orthogonal but are identical for the same-indexed users from different cells. Although with this pilot structure the channel state information (CSI) derived contains CSI from other-cell users caused by PC, the line-of-sight (LOS) component of the desired user is PC-free when the number of antennas equipped at the BS is large. Then, based on the AOAs and the contaminated CSI, the LOS component of each user served by a BS is estimated, and data are detected by using the derived LOS components. Finally, the decoded data are used to update the CSI estimate via an iterative process. The achievable spectral efficiency of the proposed scheme is analyzed in detail, and simulation results are presented to compare the performance of the proposed scheme with that of three existing schemes.

Massive MIMO With Spatially Correlated Rician Fading Channels

“…The multi-cell case was studied in [10]- [12], assuming spatially uncorrelated Rician fading within each cell and spatially uncorrelated Rayleigh fading across cells. Approximate SE expressions were derived in the UL with ZF combining [11] and in the DL with ZF [10] or regularized ZF precoding [12]. Note that these are the prior works that consider imperfect CSI, which is the practically relevant scenario, while prior works assuming perfect CSI can be found in the reference lists of [7]- [12].…”

Uplink Spectral Efficiency of Massive MIMO with Spatially Correlated Rician Fading

“…The multicell case was studied in [9]- [11], assuming spatially uncorrelated Rician fading within each cell and spatially uncorrelated Rayleigh fading across cells. Approximate SE expressions were derived in the UL with ZF combining [10] and in the DL with ZF [9] or regularized ZF precoding [11]. Note that these are the papers that consider imperfect CSI, which is the practically relevant case, while prior works assuming perfect CSI can be found in the reference lists of [6]- [11].…”

Low-complexity beam-domain channel estimation and power allocation in hybrid architecture massive MIMO systems

“…Channel estimation is crucial but intractable in massive MIMO systems [22,23]. In this subsection, we propose a low-complexity channel estimation method in the beam domain.…”