Location-based channel estimation and pilot assignment for massive MIMO systems

Abstract

Abstract-In this paper, a location-based channel estimation algorithm is proposed for massive multi-input multi-output (MI-MO) systems. By utilizing the property of the steering vector, a fast Fourier transform (FFT)-based post-processing is introduced after the conventional pilot-aided channel estimation. Under the condition that different users with the same pilot sequence have non-overlapping angle-of-arrivals (AOAs), the proposed channel estimation algorithm is capable of distinguishing these users effectively. To cooperate with the location-based channel estimation, a pilot assignment algorithm is also proposed to ensure that the users in different cells using the same pilot sequence have different AOAs at base station. The simulation results demonstrate that the proposed scheme can reduce the inter-cell interference caused by the reuse of the pilot sequence and thus improves the overall system performance significantly.

Optimal Pilot Design for Pilot Contamination Elimination/Reduction in Large-Scale Multiple-Antenna Aided OFDM Systems

“…This is in contrast to all the existing methods, which consider the signal vector over all the target BS's antennas for an individual subcarrier [6], [10], [11], [14]- [17]. Our approach to UL training has a significant advantage.…”

“…Recently, a location-aware CE scheme was proposed by relying on fast Fourier transform (FFT) based post-processing following the conventional pilot aided CE [14], which is capable of distinguishing the users associated with different angles of arrival (AOAs), even if they use the same pilot. To maximally benefit from this location-aware CE algorithm, a location-aware pilot assignment was also proposed in [14] for satisfying the condition of having non-overlapping AOAs for the users of different cells adopting the same pilot.…”

“…To maximally benefit from this location-aware CE algorithm, a location-aware pilot assignment was also proposed in [14] for satisfying the condition of having non-overlapping AOAs for the users of different cells adopting the same pilot. The advantage of this method is its appealing simplicity and efficiency.…”

“…1) An efficient signal framework for analyzing PC: All the existing schemes [6], [10], [11], [14]- [17] approach PC by considering the signals received by all the target BS's antennas on an individual OFDM subcarrier 1 . While considering a signal framework on an OFDM subcarrier basis is the natural choice for detection/precoding given each subcarrier's frequency-domain channel transfer function (FDCHTF) coefficient matrix, due to the orthogonality of the subcarriers, it is an inefficient one for approaching the CE or PC problem.…”

A Brief Survey on 5G Wireless Mobile Network

“…However, in large dimensional signal processing, channel hardening may bring some advantages to the system [72]. If we need to improve the overall massive MIMO system performance, we have to reduce the pilot contamination in Location-based channel-dense deployments estimation by disallowing all mobiles with similar Angle of Arrivals (AoAs) from sharing the same pilot [73]. The conventional massive MIMO is less energy efficient than the hybrid massive MIMO (HMM) system as it is benefited from the newer 5G architecture technologies including energy harvesting networks, heterogeneous networks, and millimetre wave [74].…”