Probabilistically shaped orthogonal frequencydivision multiplexing (PS-OFDM) signal is proposed and experimentally demonstrated in a low-cost intensity-modulation and direct-detection (IM-DD) system for optical access...
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Probabilistically shaped orthogonal frequencydivision multiplexing (PS-OFDM) signal is proposed and experimentally demonstrated in a low-cost intensity-modulation and direct-detection (IM-DD) system for optical access networks. The concatenation of constant composition distribution matcher (CCDM) and low-density parity-check (LDPC) code sequentially implements probabilistic amplitude shaping (PAS) and channel coding. Thanks to the precoding scheme, all data subcarriers can be treated equally by one optimized probabilistic distribution. Experimental results demonstrate that constant amplitude zero autocorrelation sequence (CAZAC) precoding can offer optimal performance compared to orthogonal circulant transform (OCT) precoding and discrete Fourier transform spread (DFT-spread) in terms of increasing generalized mutual information (GMI) and reducing PAPR. Moreover, probabilistically-shaped 64-QAM OFDM signal can provide shaping gains of 1.04/0.94/0.64 dB at 4.0/3.6/3.0 bits/QAM symbol compared to traditional 64-QAM OFDM signal. Meanwhile, compared to traditional 16-QAM OFDM, it can offer shaping gains of 1.64/0.64 dB at 3.6/3.0 bits/QAM symbol. In addition, net data rate ranging from 32.66 to 43.55-Gb/s over 20-km single mode fiber (SMF) can be achieved by only adjusting the probabilistic distribution.
In this study, the performances of commonly used precoding schemes are evaluated based on channel measurements carried out at 28GHz in a railway station for a massive antenna system configuration. And a hybrid precodi...
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In this study, the performances of commonly used precoding schemes are evaluated based on channel measurements carried out at 28GHz in a railway station for a massive antenna system configuration. And a hybrid precoding algorithm for a fifth generation (5G) multi-user antenna system is proposed and its performance is evaluated based on real measured channels. Specifically, An upper bound for achievable sum-rate of phased zero forcing (PZF) algorithm is derived and a precoding technique by reduction of phase shifters (PSs) named reduced-PZF (RPZF) is proposed, which can obviously reduce power consumption in hybrid precoding systems. In addition, the authors give the closed-form expression for achievable sum-rate when RPZF is used. There are no requirements in the authors' proposed scheme with complicated matrix decomposition and optimisation techniques. The simulation results show that it is possible to reduce 30 and 50% of the PSs by using the proposed hybrid precoder with better system performance in the line-of-sight (LoS) and non-LoS scenarios, respectively. In addition, the digital PSs with 3 bits low resolution can achieve the similar performance when using analogue ones.
An adaptive precoding scheme with efficient joint processing (JP) is proposed for the downlink coordinated multi-point transmission system. This scheme selects one JP technique and one precoding technique according to...
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An adaptive precoding scheme with efficient joint processing (JP) is proposed for the downlink coordinated multi-point transmission system. This scheme selects one JP technique and one precoding technique according to channel state information from the user equipment. The system-level simulation results show that the bit error rate performance of the proposed scheme is better than that of the conventional scheme.
We propose a simple linear precoder for selection-type cooperative multiple-input multiple-output communication systems. After a received symbol vector is detected at destination, the link which has the highest minimu...
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We propose a simple linear precoder for selection-type cooperative multiple-input multiple-output communication systems. After a received symbol vector is detected at destination, the link which has the highest minimum receive substream signal-to-noise-ratio between the source-destination link and the source-relay-destination link is selected as a transmission link. Under the assumption that the full channel state information is available at every node, source and relay precodering scheme, which is suitable for zero-forcing detector, is proposed. Simulation results show that the performance of the proposed relaying technique is comparable to that of the near-optimal linear protocol while offering lower computational complexity.
In this letter, multiple-input multiple-output (MIMO) techniques are proposed to improve the spectral efficiency and bit error rate (BER) performance of the conventional carrierless amplitude and phase modulation (CAP...
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In this letter, multiple-input multiple-output (MIMO) techniques are proposed to improve the spectral efficiency and bit error rate (BER) performance of the conventional carrierless amplitude and phase modulation (CAP) in visible light communication. Analytic frameworks for both multiplexing and diversity MEMO techniques are developed for CAP. The analytical expressions in line-of-sight (LOS) propagation are validated via simulation. A preceding technique is further applied to improve the power efficiency of the multiplexing scheme resulting in a signal-to-noise ratio (SNR) gain of 28.5 dB.
In downlink multiuser multiple-input multiple-output (MU-MIMO) systems, block diagonalisation (BD) is a well-known precoding technique that eliminates inter-user interference. The number of simultaneously supportable ...
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In downlink multiuser multiple-input multiple-output (MU-MIMO) systems, block diagonalisation (BD) is a well-known precoding technique that eliminates inter-user interference. The number of simultaneously supportable users with BD is limited by the number of base station transmit antennas and the number of user receive antennas. Traditional MU-MIMO scheduling algorithms focus on sum capacity. However, these user scheduling algorithms might not be optimal with respect to energy efficiency. Here, the authors consider the energy-efficient MU-MIMO scheduling that maximises the energy efficiency. The brute-force search for the optimal user set, however, is computationally prohibitive. Therefore they propose a low-complexity user scheduling algorithm for energy-efficient MU-MIMO systems. They first obtain an approximation expression for the energy efficiency by utilising the upper bound of the MU-MIMO system capacity. Then they show that the maximum energy efficiency can be achieved if the scheduling user set is selected to obtain the largest matrix volume. The numerical results show that the proposed algorithm achieves a good tradeoff between energy efficiency and computational complexity. They also consider the problem of maintaining fairness among users, and propose a simplified proportional fair (PF) scheduling algorithm.
This paper explores the effect of imperfect channel state information (CSI) on spatial hiding anti-jam (AJ) communications technique. Recently a fundamental technique of hiding a signal is proposed that provides a pre...
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ISBN:
(纸本)9781479967704
This paper explores the effect of imperfect channel state information (CSI) on spatial hiding anti-jam (AJ) communications technique. Recently a fundamental technique of hiding a signal is proposed that provides a precoding technique that allows a pair of two-antenna transceivers to communicate while being jammed intentionally by a malicious single-antenna node. The precoder uses a small amount of CSI to shape the signal to appear orthogonal to the jammer at the intended receiver. However, performance of the scheme depends on the quality of two estimated parameters -transceiver and jamming CSI. In practice, CSI estimation is always subject to error due to the presence of noise, statistical characteristics of wireless channel, and limitations of hardware. By modeling the CSI estimation error as independent complex Gaussian random variables, analytical model for post-processing residual interference is derived in closed-form for both transceiver and jamming CSI estimation error. In addition, a lower bound for jammers interference as a function of jamming CSI estimation error is derived. Through simulation we demonstrate the effect of imperfect CSI on spatial hiding anti-jam and validate the analytical model as well.
In this paper we analyse the performance of a MIMO receive algorithm that represents a modification of a precoding technique. Thereby we demonstrate the flexibility of these precoding techniques and investigate the po...
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ISBN:
(纸本)296005511X
In this paper we analyse the performance of a MIMO receive algorithm that represents a modification of a precoding technique. Thereby we demonstrate the flexibility of these precoding techniques and investigate the possibility of applying the same algorithms at the base station (BS)/access point (AP) for both downlink (DL) and uplink (UL) MIMO processing. Unlike previously reported results where all users in the system are equipped with only one antenna, we investigate a more general case where users can be equipped with an arbitrary number of antennas. By combining one of the previously proposed precoding algorithm and space-time codes we are able to provide an SNR gain of more than 3 dB compared to V-BLAST.
In this paper,we introduce ablock iterative frequency domain decision feedback equalizer with noise prediction(NP-BI) for single-carrier(SC) multiple input multiple output(MTMO) relay ***,we derive the minimum mean-sq...
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ISBN:
(纸本)9781509012473
In this paper,we introduce ablock iterative frequency domain decision feedback equalizer with noise prediction(NP-BI) for single-carrier(SC) multiple input multiple output(MTMO) relay ***,we derive the minimum mean-squared error(MMSE) equalizer at the destination *** the decision feedback equalizer coefficients can be calculated according to the error covariance matrix of the MMSE equalizer and the equivalent channel frequency-domain(FD) ***,we combine the spatial precoding matrix with the decision feedback equalizer at the source node,which performs better than the frequency domain equalization with noise prediction(FDE-NP),especially when the number of antennas is *** addition,NP-BI has a lower computational complexity than FDE-NP.
Based on the background of Massive MIMO (Multiple-Input Multiple-Output) system, this paper focuses on whether precoding technology can effectively reduce the impact of pilot pollution, and a hybrid precoding scheme b...
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ISBN:
(纸本)9781728181813
Based on the background of Massive MIMO (Multiple-Input Multiple-Output) system, this paper focuses on whether precoding technology can effectively reduce the impact of pilot pollution, and a hybrid precoding scheme based on all-digital precoding and analog beamforming is proposed. The results show that the hardware complexity and cost of the system can be reduced effectively on the premise that the basic performance indexes are close.
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