本期目录

2019年 26卷 4期 刊出日期：2019-08-31



Wireless

Miniaturized single-channel concurrent dual-band mixing architecture with one frequency-divided local oscillator

Yu Cuiping, Gao Yuan, Wu Fan, Liu Yuanan

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1011

摘要 ( 465 ) PDF (2345 KB)( 114 )

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Concurrent dual-band transceiver system is widely used in conditions where transceivers are required to work in

different bands at the same time. In order to miniaturize the concurrent dual-band transceiver system and reduce the

number of components in a transceiver, a novel receiver mixing structure with one frequency-divided local oscillator

is proposed. Compared to traditional mixing architecture with two local oscillators, the proposed structure reduces a

local oscillator and a bandpass filter. In addition, the output signal of proposed mixing architecture has a better

error vector magnitude (EVM) performance. The proposed mixing architecture is described in detail; the method of

local oscillator signal frequency selection and the applicable conditions of the proposed structure are derived through

math formula; and the conclusions are demonstrated by experimental results.

Physical layer security enhanced system with under-sampling spectrum-sparse signals

Li Lintao, Liu Yuanan

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1012

摘要 ( 446 ) PDF (1211 KB)( 143 )

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The ubiquity of wireless communication systems has resulted in extensive concern regarding their security issues.

A practical secure transmission scheme based on under-sampling spectrum-sparse signals is designed. Secure

transmission is initialized as the intended receiver transmits a pilot signal for the transmitter, to perform channel

sounding and clock synchronization according to the channel reciprocal principle. Then, sampling clock offset

compensation and precoding method based on channel state information (CSI) can be conducted at the transmitter's

end. Because the intended receiver adopts an under-sampling method based on active aliasing which depends very

sensitively on accurate sampling clock and CSI, the eavesdroppers can hardly intercept the signal. Closed form

expression of symbol error rate (SER) at the intended receiver's end and secrecy capacity in fading wiretap

channel has been derived. Numerical evaluation and simulations are carried out to validate the effectiveness of the

proposed strategy.

Spectrum efficiency maximization with trajectory design in UAV-enabled mobile relaying

Sun Chuanzhi, Hu Zhiqun, Wen Xiangming, Lu Zhaoming, Qi Hang

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1013

摘要 ( 550 ) PDF (439 KB)( 134 )

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With the advantages of low cost and high mobility, unmanned aerial vehicles (UAVs) have played an important

role in wireless communication. We investigate a UAV-enabled mobile relaying system, where a UAV is used as a

mobile relay to assist in the communication from a ground source to a ground destination since their direct link is

blocked. Unlike the conventional mobile relay in which the UAV adopts straight line or circular trajectory, we

consider a more general elliptical trajectory and use realistic channel models. By assuming that the UAV employs

time-division duplexing (TDD) based decode-and-forward (DF) relaying, we jointly optimize the time allocations

and the UAV trajectory to formulate the maximization of spectrum efficiency (SE). The simulation results show that

the trajectory we designed achieves a higher SE than the optimal circular trajectory and static relaying.

Coalitional game-based WiFi offloading algorithm in heterogeneous networks

Sun Lin, Zhu Qi

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1014

摘要 ( 306 ) PDF (1400 KB)( 117 )

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Aiming at the coexistence of cellular network and wireless fidelity (WiFi) network, a coalitional game-based

WiFi offloading algorithm in heterogeneous networks is proposed. Firstly, this paper defines the user fairness utility

function that comprehensively considers the user communication rate, cost and delay. Then, the coalitional game

model including two types of coalitions is constructed. To control the transfer of users among coalitions, a coalition

transfer criterion that simultaneously improves the user's individual utility and the total system utility is proposed.

In addition, this paper presents a channel allocation scheme that ensures full utilization of system resources to

maximize the total utility of the system. The simulation results show that the proposed offloading algorithm can

reasonably utilize the resources of cellular network and WiFi network, and improve the utility of users and system.

12-bit 2.6 GS/ s RF DAC based on return-to-zero technology

Li Xiaopeng, Wang Zhigong, Zhang Yi, Zhang Youtao, Zhang Mi

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1015

摘要 ( 281 ) PDF (2813 KB)( 200 )

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A 12-bit 2.6 GS/ s radio frequency digital to analog converter (RF DAC) based on 1 um GaAs heterojunction

bipolar transistor (HBT) process is presented. The DAC integrates a 4:1 multiplexer to reduce the data rate of

input ports, which greatly facilitates the application. DAC core adopts 4 +8 segmented current steering structure. R-2R ladder network is used for 8 least significant bit (LSB) to realize binary current weighting and thermometer

coding is used for 4 most significant bit (MSB). Return-to-zero (RZ) technology is used to expand the effective

bandwidth of DAC output to the third Nyquist band. The proposed DAC has a better output power flatness and

spurious-free dynamic range (SFDR). Compared to traditional DAC, measured results demonstrate that the output

power of this RZ DAC is increased by 33 dB and the SFDR is enhanced by 27 dB near the second Nyquist band.

Artificial Intelligence

Flocking of multi-agent system with high frequency feedback robust control

Zhang Qing, Wang Jie, Yang Zhengquan, Chen Zengqiang

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1016

摘要 ( 200 ) PDF (1434 KB)( 135 )

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Flocking of multi-agent system with high-frequency feedback robust control is put forward in detail. The

controller that has high-frequency feedback robust control is designed; it is proved that the velocity error is bounded

and no collision occurs between the multi-agent under the action of the high-frequency feedback robust control by

employing the boundedness theorem and the Lyapunov stability theory. Flocking of multi-agent system can be

formed under the action of the high-frequency feedback robust control. Flocking of multi-agent system with high-frequency feedback robust control is realized in numerical simulation. Compared with the state diagram and velocity

error diagram of the original flocking of multi-agent system in the simulation, flocking of multi-agent system with

high-frequency feedback robust control has better stability.

Supervised learning of enhancing convolutional Hash for image retrieval

Zhai Qi, Jiang Mingyan

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1017

摘要 ( 218 ) PDF (6709 KB)( 143 )

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Deep convolutional neural network (CNN) makes great breakthroughs in computer vision. Recently, many works have demonstrated that the performance of the CNN depends on the stacked convolutional layers. It is obvious that the features of the fully connected layers lose the topological structures of images, and the convolutional layer features contain a large amount of redundant information that interferes with the performance of model. Thus, we propose an effective supervised deep Hashing method, enhancing convolutional deep Hashing (ECDH), which learns the binary codes from the strengthened convolutional layer. Specifically, an enhanced convolutional Hash layer is constructed between the top convolutional layer and the output layer, enhancing the local features of the convolutional layer outputs while learning the binary codes by optimizing an objective function. The proposed method works well for existing deep learning models such as Alex neural network (AlexNet), visual geometry group neural network (VGGNet), residual neural network (ResNet), and is easier to be trained. Compared with state-of-the-art methods, extensive experiments show that the proposed method achieves better retrieval performance.

Improved ECG signal compression method for E-healthcare

Gao Miao, Yu Zhiguo, Li Qingqing, Wei Jinghe, Gu Xiaofeng

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1018

摘要 ( 187 ) PDF (1357 KB)( 184 )

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For achieving a higher compression ratio (CR) in compression sensing, the time-sparse bio-signals, such as electrocardiograph (ECG), are generally directly filtered via a dynamic or fixed threshold, however, inevitably leading to the loss of critical diagnostic bio-information. We propose a compression scheme to reduce the transmitting loss. Instead of the directly utilizing the original ECG data, the residuals between original and synthetic ECG signals are applied as the input signal. We employ the dynamic model to guarantee the consistency between the synthetic ECG signals waves (P, Q, R, S, and T) and the originals. The feasibility of the proposed method is tested through operating on the recorded ECG signals from a healthy human. During the process of building simulation platform, the sparsity, percentage root mean difference (PRD) versus sampling frequency, and signals reconstruction algorithm are fully taken into account. Before compression, we set the threshold to filter the residual waves, in which utilizing the residuals as input data by setting the thresold as 0.01 mV and 0.08 mV resulted the amount reduction of the transmitting data by 18% and 81.2%, respectively. And the simulation results show that CR can reach 2.75 when the PRD value is less than 9%.

Others

Lattice-based hierarchical identity-based broadcast encryption scheme in the standard model

Tang Yongli, Wang Mingming, Ye Qing, Qin Panke, Zhao Zongqu

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1019

摘要 ( 295 ) PDF (460 KB)( 161 )

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Lattice-based hierarchical identity-based broadcast encryption ( H-IBBE) schemes have broad application prospects in the quantum era,because it reduces the burden of private key generator (PKG) and is suitable for one-to-many communication. However, previous lattice-based H-IBBE schemes are mostly constructed in the random oracle model with more complex trapdoor delegation process and have lower practical application. A lattice-based H-IBBE is proposed in the fixed dimension under the standard model, which mainly consists of binary tree encryption (BTE) system, MP12 trapdoor function and ABB10b trapdoor delegation algorithm. First, this paper uses BTE system to eliminate the random oracle so that the scheme can be implemented under the standard model, and it also uses MP12 trapdoor function to reduce trapdoor generation complexity and obtains a safe and efficient trapdoor matrix; Second, this paper uses ABB10b trapdoor delegation algorithm to delegate user爷s private key, and the trapdoor matrices' dimensions are the same before and after the trapdoor delegation. Comparative analysis shows that trapdoor delegation process reduces complexity, and the size of cipher-text and trapdoor matrix does not increase with deeper trapdoor delegation process. This paper achieves indistinguishability of cipher-texts under a selective chosen-cipher-text and chosen-identity attack (INDr-sID-CCA) security in the standard model based on learning with errors (LWE) hard assumption.

Quality of experience models for network video quality

Shi Zhiming, Huang Chengti

中国邮电高校学报(英文), 2019, 26 (4). doi： DOI: 10.19682/j.cnki.1005-8885.2019.1020

摘要 ( 237 ) PDF (2857 KB)( 216 )

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Nowadays, the service of network video is increasing explosively. But the quality of experience (QoE) model of network video quality is not stable. The video quality may be impaired by many factors. This paper proposes QoE models for network video quality. It consists of two components: 1) the perceptual video quality model considering the impair factors related to video content as well as distortion caused by content and transmission. Next the model is built through a decision tree using a set of measured features form the network video. This proposed model can qualitatively give the grade of video quality and improve the accuracy of prediction. 2) Based on the above model, another model is proposed to give the concrete objective score of video quality. It also considers original impair factors and predicts the video quality using fuzzy decision tree. The two models have their own advantages. The first model has a good computational complexity; the second model is more precise. All the models are simulated by actual experiments. They can improve the accuracy of objective model. The detail results are shown.