Cache-Aided Multiuser Cognitive Relay Networks With Outdated Channel State Information

Lai, Xiazhi; Xia, Junjuan; Tang, Maobin; Zhang, Haochuan; Zhao, Junhui

doi:10.1109/access.2018.2829026

Cited by 46 publications

(19 citation statements)

References 43 publications

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“…It could collect the power leakage with much fewer RF chains than full-digital architecture. For future work, we attempt to extend our work in this paper with some other existing wireless techniques [49,50] and design hybrid precoder for the wideband mmWave system with cache techniques [6][7][8] to meet the uRLLC requirement in the 5G/B5G communication system.…”

Section: Resultsmentioning

confidence: 99%

“…The capacity of the fifth generation (5G) wireless communication system is projected to bring 1000× increase to meet the data explosion by 2020 [1][2][3][4][5]. To achieve the ultra-reliable and available low-latency communications (uRLLC) for 5G/Beyond-5G (B5G) wireless system, more bandwidth, more advanced signal processing technologies, and together with cache techniques [6][7][8], are needed to guarantee the reliable and highly effective transmission. Millimeter wave emerges as the new radio in 5G communications to leverage the bandwidth shortage.…”

Section: Introductionmentioning

confidence: 99%

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Rotman lens-based two-tier hybrid beamforming for wideband mmWave MIMO-OFDM system with beam squint

Liu

Zhu

2018

J Wireless Com Network

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In this paper, we study the hybrid beamforming for the wideband mmWave multiuser MIMO-OFDM system. We characterize the frequency-dependent beam angle problem, i.e., beam squint effect. Firstly, we extend the mmWave channel model from the Saleh-Valenzuela representation with the consideration of beam squint. Secondly, a two-tier hybrid beamforming is proposed to achieve the maximum spectral efficiency in wideband mmWave multiuser MIMO-OFDM system. In the first tier, the Rotman lens array is adopted as the analog precoder to provide true-time-delay (TTD) and reduce the beam squint impairment. Moreover, the first-tier baseband precoder is designed based on block diagonalization (BD) to cancel inter-user interference. We further consider the finite spatial resolution and power leakage problem of the lens array. The second-tier hybrid precoder is proposed to collect the leak power with the phase shifter array. The optimal second-tier hybrid precoder design is formulated as the matrix factorization problem, and the two-tier hybrid precoding algorithm is based on the alternative minimization. It is found that both the beam squint and frequency-selective effect should be considered in the wideband mmWave system. Simulation results show that the proposed two-tier hybrid precoder could reduce beam squint impairment and inter-user interference, and could approximate to the optimal full-digital precoder with much fewer RF chains.

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Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Rotman lens-based two-tier hybrid beamforming for wideband mmWave MIMO-OFDM system with beam squint

Liu

Zhu

2018

J Wireless Com Network

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“…A similar investigation was conducted in [15]. Moreover, when the number of antennas become very large, the availability of perfect CSI gets very tricky, which also becomes another important issue in massive MIMO systems [16]. By exploiting user preference and spatial locality, the authors in [17,18] investigated the optimal cache policy to minimize the average file download time in massive MIMO system.…”

Section: Related Workmentioning

confidence: 99%

Multiuser precoding scheme and achievable rate analysis for massive MIMO system

Tan

Huang

Yang

et al. 2018

J Wireless Com Network

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We analyze the downlink multiuser precoding of massive multiple input multiple output (MIMO) system, where the base station (BS) has ideal channel state information (CSI) and adopts three types of different linear precoding schemes, i.e., maximum ratio transmission (MRT), zero-forcing (ZF), and minimum mean squared error (MMSE). Under a Rayleigh fading channel, we attain the exact expressions on the achievable rate for these three precoding schemes. Moreover, we provide several insights on the achievable rates and reveal the relation of the number of BS antennas, the number of users, and the input signal-to-noise ratio (SNR) with the achievable rates respectively. It is found in general that the achievable rate increases with the number of BS antennas and the input SNR. To be more specific, the MRT precoding scheme is much inferior to the ZF and MMSE precoding schemes and tends to be at a fixed rate at the high SNR case. On the contrary, the MRT precoding scheme outperforms ZF precoding schemes at the low SNR case. Moreover, the total achievable rate always does not increase with the number of users and the optimal number of users always exists for the ZF and MMSE precoding schemes.

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“…Due to the broadcast nature of wireless transmission, it is of vital importance to guarantee the transmission security from the application layer [15][16][17][18][19] to physical layer [20,21]. The authors in [22] provided the framework of wiretap channels, which gives a general way to analyze and design the secure physical-layer security.…”

Section: Introductionmentioning

confidence: 99%

Impact of Antenna Selection on Physical‐Layer Security of NOMA Networks

Deng

Fan

et al. 2018

Wireless Communications and Mobile Computing

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This paper studies the impacts of antenna selection algorithms in decode-and-forward (DF) cooperative nonorthogonal multiple access (NOMA) networks, where the secure information from the relay can be overheard by an eavesdropper in the networks. In order to ensure the secure transmission, an optimal antenna selection algorithm is proposed to choose one best relay's antenna to assist the secure transmission. We study the impact of antenna selection on the system secure communication through deriving the analytical expression of the secrecy outage probability along with the asymptotic expression in the high regime of signal-tonoise ratio (SNR) and main-to-eavesdropper ratio (MER). From the analytical and asymptotic expressions, we find that the system secure performance is highly dependent on the system parameters such as the number of antennas at the relay, SNR, and MER. In particular, the secrecy diversity order of the system is equal to the antenna number, when the interference from the second user is limited.

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Cache-Aided Multiuser Cognitive Relay Networks With Outdated Channel State Information

Cited by 46 publications

References 43 publications

Rotman lens-based two-tier hybrid beamforming for wideband mmWave MIMO-OFDM system with beam squint

Rotman lens-based two-tier hybrid beamforming for wideband mmWave MIMO-OFDM system with beam squint

Multiuser precoding scheme and achievable rate analysis for massive MIMO system

Impact of Antenna Selection on Physical‐Layer Security of NOMA Networks

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