Optimal pilot design in massive MIMO systems based on channel estimation

Ni, Shanjin; Zhao, Junhui; Gong, Yi

doi:10.1049/iet-com.2016.0889

Cited by 43 publications

(29 citation statements)

References 38 publications

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“…Transmit waveform design under a detection constraint is stated in some works [43,44]. e problem of code optimization for target recognition in the presence of clutter interference is addressed.…”

Section: Complexitymentioning

confidence: 99%

Optimizing Transmit Sequence and Instrumental Variables Receiver for Dual-Function Complexity System

Yao

Zhao

2020

Complexity

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This correspondence deals with the joint cognitive design of transmit coded sequences and instrumental variables (IV) receive filter to enhance the performance of a dual-function radar-communication (DFRC) system in the presence of clutter disturbance. The IV receiver can reject clutter more efficiently than the match filter. The signal-to-clutter-and-noise ratio (SCNR) of the IV filter output is viewed as the performance index of the complexity system. We focus on phase only sequences, sharing both a continuous and a discrete phase code and develop optimization algorithms to achieve reasonable pairs of transmit coded sequences and IV receiver that fine approximate the behavior of the optimum SCNR. All iterations involve the solution of NP-hard quadratic fractional problems. The relaxation plus randomization technique is used to find an approximate solution. The complexity, corresponding to the operation of the proposed algorithms, depends on the number of acceptable iterations along with on and the complexity involved in all iterations. Simulation results are offered to evaluate the performance generated by the proposed scheme.

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Section: Complexitymentioning

confidence: 99%

Optimizing Transmit Sequence and Instrumental Variables Receiver for Dual-Function Complexity System

Yao

Zhao

2020

Complexity

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“…In particular, massive MIMO technology, which utilizes a very large number of antennas at the BS and simple signal processing to provide services for a comparatively small (compared to the number of antennas) number of active mobile users, is a promising approach for efficient transmission of massive amounts of information and is regarded as a key technology in 5G [13]. Pilot contamination is a major impairment in massive MIMO systems [14] and many approaches have been proposed to solve this problem [15][16][17][18]. For example, the authors of [18] proposed an approach based on Chu sequences, which efficiently reduces the effect of pilot contamination.…”

Section: Introductionmentioning

confidence: 99%

“…Pilot contamination is a major impairment in massive MIMO systems [14] and many approaches have been proposed to solve this problem [15][16][17][18]. For example, the authors of [18] proposed an approach based on Chu sequences, which efficiently reduces the effect of pilot contamination.…”

Section: Introductionmentioning

confidence: 99%

Data-Aided Secure Massive MIMO Transmission Under the Pilot Contamination Attack

Wen

Chen

et al. 2019

IEEE Trans. Commun.

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In this paper, we study the design of secure communication for time division duplex multi-cell multi-user massive multiple-input multiple-output (MIMO) systems with active eavesdropping. We assume that the eavesdropper actively attacks the uplink pilot transmission and the uplink data transmission before eavesdropping the downlink data transmission of the users. We exploit both the received pilots and the received data signals for uplink channel estimation. We show analytically that when the number of transmit antennas and the length of the data vector both tend to infinity, the signals of the desired user and the eavesdropper lie in different eigenspaces of the received signal matrix at the base station provided that their signal powers are different. This finding reveals that decreasing (instead of increasing) the desired user's signal power might be an effective approach to combat a strong active attack from an eavesdropper. Inspired by this observation, we propose a data-aided secure downlink transmission scheme and derive an asymptotic achievable secrecy sum-rate expression for the proposed design. For the special case of a single-cell singleuser system with independent and identically distributed fading, the obtained expression reveals that the secrecy rate scales logarithmically with the number of transmit antennas. This is the same scaling law as for the achievable rate of a singleuser massive MIMO system in the absence of eavesdroppers. Numerical results indicate that the proposed scheme achieves significant secrecy rate gains compared to alternative approaches based on matched filter precoding with artificial noise generation and null space transmission.

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“…PC causes major limitations in the performance of massive MIMO systems, even though the number of BS antennas goes to infinity, and thus PC has become one of the main research topics in massive MIMO systems [4,5]. A lot of efforts have been made to overcome this challenging issue of PC [10][11][12][13][14][15][16][17][18][19]. A MMSE-based multi-cell precoding technique was proposed in [10], where each BS creates its own precoding matrix to minimize the total of squared errors of its users and the interference with other cells users.…”

Section: Introductionmentioning

confidence: 99%

Worst Cell Based Pilot Allocation in Massive MIMO Systems

Dao

Kim

2018

Electronics

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Massive multiple-input multiple-output (MIMO) has been viewed as an advanced technique in future 5G networks. Conventional massive MIMO systems consist of cellular base stations (BS) equipped with a very large number of antennas to simultaneously serve many single-antenna users. Unfortunately, massive MIMO system’s performance is limited by pilot contamination (PC) problem. Conventionally, all users in massive MIMO systems are assigned pilot randomly. In this paper, we propose a pilot allocation algorithm based on a cell with the worst channel quality (WCPA) algorithm to improve the uplink achievable sum rate of the system. Specifically, WCPA exploits the large-scale coefficients of fading channels between the BSs and users. According to the number of available orthogonal pilot sequences, we choose some of the highest inter-cell interfering users and assign each of them a unique pilot sequence if the number of pilot sequences is more than the number of users in a cell. Next, we choose a target cell with the worst channel quality, and gather the highest channel gain user in the target cell and the lowest interfering user in the other cells in the same group in a sequential way by assigning them the same pilot sequence. The simulation results show the outperformance of the proposed algorithm compared to the conventional pilot allocation schemes.

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Optimal pilot design in massive MIMO systems based on channel estimation

Cited by 43 publications

References 38 publications

Optimizing Transmit Sequence and Instrumental Variables Receiver for Dual-Function Complexity System

Optimizing Transmit Sequence and Instrumental Variables Receiver for Dual-Function Complexity System

Data-Aided Secure Massive MIMO Transmission Under the Pilot Contamination Attack

Worst Cell Based Pilot Allocation in Massive MIMO Systems

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