Robust Pilot Decontamination Based on Joint Angle and Power Domain Discrimination

Abstract

We address the problem of noise and interference corrupted channel estimation in massive MIMO systems. Interference, which originates from pilot reuse (or contamination), can in principle be discriminated on the basis of the distributions of path angles and amplitudes. In this paper we propose novel robust channel estimation algorithms exploiting path diversity in both angle and power domains, relying on a suitable combination of the spatial filtering and amplitude based projection. The proposed approaches are able to cope with a wide range of system and topology scenarios, including those where, unlike in previous works, interference channel may overlap with desired channels in terms of multipath angles of arrival or exceed them in terms of received power. In particular we establish analytically the conditions under which the proposed channel estimator is fully decontaminated. Simulation results confirm the overall system gains when using the new methods.

A Survey of Enabling Technologies for Network Localization, Tracking, and Navigation

“…For instance, in the physical layer, network processes that can be benefited include spatial spectrum sensing for cognitive radio and interference coordination in 5G, slow adaptive modulation and coding or channel estimation, beamforming, pilot decontamination in MIMO systems as described in [264], [265], and Channel State Information (CSI) estimation [266]- [269]. Medium Access Control (MAC) layer applications include resource scheduling algorithms (e.g., for frequency reuse), inter-cell interference coordination techniques, and multicasting algorithms.…”

A Robust Estimation and Tracking of Channel for Time and Frequency Selective MIMO-OFDM Systems

“…Since unlike users channels incline to be a pair wise orthogonal in a massive antenna system, blind discrimination is accomplishable between the interferences and desired signals based on the average channel gains which are prior known [22]. Recently, author in [23] proposed an algorithm for CE by path diversity exploitation in both domains i.e., angle and power. In general, the trend of adopting or trusting on the prior knowledge of a) the CIR length and b) Doppler rate, often become the constriction to trust on sufficiently higher order polynomial model leading in complicated algorithms, showing an impractical solvent for real time CE where the pilot optimality finally reckons on the CE speed.…”

Uplink interference reduction in Large Scale Antenna Systems

“…The coefficients β jkl are modeled, according to [15], as 10 log 10 (β jkl ) = −127.8 − 35 log 10 (d jkl ) + X jkl (2) where d jkl denotes the distance (in km) between the user and base station and…”

“…In a massive MIMO system, the base station (BS) is equipped with a very large number of antennas that significantly exceeds the number of users. It was shown in [1] antennas tends to infinity, the main limiting factor in performance is pilot contamination, which arises due to the fact that the users in different cells unavoidably use nonorthogonal pilot signals during estimation of the channel.A number of works in the literature have been devoted to the use of efficient schemes in order to mitigate the pilot contamination effect, see for example [2]- [6] and references therein. The works in [2]- [4] assume the channel to be low rank due to the presence of a smaller number of multipath components when compared with the number of antennas.…”