Pilot Sequence Design for Mitigating Pilot Contamination With Reduced RF Chains

Ioushua, Shahar Stein; Eldar, Yonina C.

doi:10.1109/tcomm.2020.2979142

Cited by 17 publications

(15 citation statements)

References 50 publications

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“…[4][5][6] The problem of pilot contamination has been studied extensively in the recent years. 7,8 It has been proved that as the number of BS antenna approaches infinity, the effects of fast fading coefficients, uncorrelated noise, and intra-cellular interference disappear. However, the effects of inter-cell interference remain as explained in literature.…”

Section: Introductionmentioning

confidence: 99%

Efficient pilot reuse algorithms for massive MIMO cellular system

Dey

Pattanayak

Gurjar

et al. 2020

Int J Communication

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Summary Pilot contamination has come up as one of the major limitations of massive multiple‐input multiple‐output. In the recent past, the pilot contamination resulted by the pilot reuse in inter‐cell system has been successfully handled. In this paper, three efficient algorithms have been proposed to reduce the pilot contamination in intra‐cell system. These schemes emphasize on assigning the available pilots to the users based upon their channel qualities by considering the interfering degree of the various pilot sequences. The first proposed algorithm is based on water filling approach, which attains the system throughput very close to that of brute‐force exhaustive search algorithm (ESA) and performs the best among the three proposed algorithms in terms of system throughput. The second algorithm is designed for achieving better user fairness (by assigning less interfering pilots to the poor channel conditioned users). The third algorithm improves the system throughput as compared to the second algorithm without losing much in terms of user fairness. Furthermore, the computational complexity incurred by all the proposed algorithms is much less than that of ESA.

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Section: Introductionmentioning

confidence: 99%

Efficient pilot reuse algorithms for massive MIMO cellular system

Dey

Pattanayak

Gurjar

et al. 2020

Int J Communication

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“…Pilot sequence division in chain network [199,200], large scale fading precoding [201], zero-forcing (ZF) precoding [202] Non-ideal transceiver hardware [203], I/Q imbalance [204], transceiver impairment in multi-user multi-cell [205], oscillator phase noise [206], transmitter branches distortion noise [207], non-reciprocal transceiver [208], pilot sequence in-band FD M-MIMO [209] Unmanned aerial vehicles Echo state network [210], analysis of interference in UAV [211], power control and coverage extension for uplink (UL)-downlink (DL) [212], impact of UL interference [213], multi-beam UAV UL [214], ICIC design UAV UL [215], cooperative NOMA [216] Downstream interference issues in different scenarios of cellular users and UAVs…”

Section: Challenges Mitigation Methodology Limitation Pilot Contaminationmentioning

confidence: 99%

“…Other sources of pilot intrusions have recently been recognized, for instance, hardware impairments distortion [203][204][205][206][207]. Subsequently, a non-reciprocal transceiver is highly vulnerable to interference because of the RF chain's internal clock design [208]. Also, the pilot symbol interference coordination in in-band FD (IBFD) M-MIMO networks is assumed to be complex due to pilot reuse factor 1 and resulted in SI.…”

Section: A Pilot Contaminationmentioning

confidence: 99%

Interference Management in 5G and Beyond Network: Requirements, Challenges and Future Directions

et al. 2021

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In the modern technological world, wireless communication has taken a massive leap from the conventional communication system to a new radio communication network. The novel concept of Fifth Generation (5G) cellular networks brings a combination of a diversified set of devices and machines with great improvement in a unique way compared to previous technologies. To broaden the user's experience, 5G technology provides the opportunity to meet the people's potential necessities for efficient communication. Specifically, researchers have designed a network of small cells with unfamiliar technologies that have never been introduced before. The new network design is an amalgamation of various schemes such as Heterogeneous Network (HetNet), Device-to-Device (D2D) communication, Internet of Things (IoT), Relay Node (RN), Beamforming, Massive Multiple Input Multiple Output (M-MIMO), millimeter-wave (mm-wave), and so on. Also, enhancement in predecessor's techniques is required so that new radio is compatible with a traditional network. However, the disparate technological models' design and concurrent practice have created an unacceptable intervention in each other's signals. These vulnerable interferences have significantly degraded the overall network performance. This review article scrutinizes the issues of interferences observed and studied in different structures and techniques of the 5G and beyond network. The study focuses on the various interference effect in HetNet, RN, D2D, and IoT. Furthermore, as an in-depth literature review, we discuss various types of interferences related to each method by studying the state-of-the-art relevant research in the literature. To provide new insight into interference issue management for the next-generation network, we address and explore various relevant topics in each section that help make the system more robust. Overall, this review article's goal is to guide all the stakeholders, including students, operators, engineers, and researchers, aiming to explore this promising research theme, comprehend interferences and their types, and related techniques to mitigate them. We also state methodologies proposed by the 3 rd Generation Partnership Project (3GPP) and present the promising and feasible research directions toward this challenging topic for the realization of 5G and beyond network.

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“…Then, exploiting the angular sparsity of the mmWave channel, the AoA and AoD estimates are obtained. The authors of [32] and [33] exploit projection approximation subspace tracking with deflation (PASTd) algorithm to track the subspace and estimate the right (left) singular vector at the transmitter (receiver).In [34], [35], the authors consider a multi-user multi-cell communication system where each user is equipped with one antenna. Assuming a Kronecker channel model, with a priori known channel's covariance matrices, the authors estimate the channel matrix by jointly designing the pilot sequences (to mitigate the effect of pilot contamination) and analog combiners that yield the minimum channel estimation error.…”

mentioning

confidence: 99%

“…In [34], [35], the authors consider a multi-user multi-cell communication system where each user is equipped with one antenna. Assuming a Kronecker channel model, with a priori known channel's covariance matrices, the authors estimate the channel matrix by jointly designing the pilot sequences (to mitigate the effect of pilot contamination) and analog combiners that yield the minimum channel estimation error.…”

mentioning

confidence: 99%

Hybrid Analog and Digital Beamforming Design for Channel Estimation in Correlated Massive MIMO Systems

Mirzaei,

ShahbazPanahi,

Sohrabi

et al. 2021

Preprint

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In this paper, we study the channel estimation problem in correlated massive multiple-input-multiple-output (MIMO) systems with a reduced number of radio-frequency (RF) chains. Importantly, other than the knowledge of channel correlation matrices, we make no assumption as to the structure of the channel. To address the limitation in the number of RF chains, we employ hybrid beamforming, comprising a low dimensional digital beamformer followed by an analog beamformer implemented using phase shifters. Since there is no dedicated RF chain per transmitter/receiver antenna, the conventional channel estimation techniques for fully-digital systems are impractical. By exploiting the fact that the channel entries are uncorrelated in its eigen-domain, we seek to estimate the channel entries in this domain. Due to the limited number of RF chains, channel estimation is typically performed in multiple time slots. Under a total energy budget, we aim to design the hybrid transmit beamformer (precoder) and the receive beamformer (combiner) in each training time slot, in order to estimate the channel using the minimum mean squared error criterion. To this end, we choose the precoder and combiner in each time slot such that they are aligned to transmitter and receiver eigendirections, respectively. Further, we derive a water-filling-type expression for the optimal energy allocation at each time slot. This expression illustrates that, with a low training energy budget, only significant components of the channel need to be estimated. In contrast, with a large training energy budget, the energy is almost equally distributed among all eigen-directions. Simulation results show that the proposed channel estimation scheme can efficiently estimate correlated massive MIMO channels within a few training time slots. TABLE I SUMMARY OF RELATED WORKS Frequency Channel Model Assumption Estimation Technique Reference CS-based [15], [21]-[24], [27], [29], [30] mmWave Parameteric Sparsity Beam training followed by CS-based resolution refining [28] ESPRIT [25] MUSIC [31] PASTd [32], [33] Microwave and mmWave Kronecker Known Channel Correlations MMSE [34], [35] training approach, while a subsequent CS algorithm refines the resolution. As an alternative to adaptive CS algorithms, traditional random CS approaches exploiting pseudo-random weights are used in a phased array MIMO system with a hybrid structure [24], [29]. The authors of [23] apply random CS with simpler analog beamformers, where the network of switches is replaced with the phase-shifter network 1 . In [30], the CSbased channel estimation algorithm extended to a mmWave communication system equipped with one-bit analog-to-digital converters (ADCs) and HB. The authors of [25], [31]-[33] propose non-CS-based techniques to estimate the channel in massive MIMO systems with the hybrid precoder/combiner structure. Assuming the parametric channel model, the authors in [31] exploit twodimensional beamspace multiple signal classification (MU-SIC) to estimate the path directions followed by a leasts...

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Pilot Sequence Design for Mitigating Pilot Contamination With Reduced RF Chains

Cited by 17 publications

References 50 publications

Efficient pilot reuse algorithms for massive MIMO cellular system

Efficient pilot reuse algorithms for massive MIMO cellular system

Interference Management in 5G and Beyond Network: Requirements, Challenges and Future Directions

Hybrid Analog and Digital Beamforming Design for Channel Estimation in Correlated Massive MIMO Systems

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