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Reliability-Optimal Pilot-Assisted Transmission for URLLC over Non-Reciprocal MISO Channels: TDD or FDD?

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China Communications 2022年第4期19卷 14-27页

作者： Yuncong Xie pinyi ren School of Information and Communications Engineering Xi’an Jiaotong UniversityXi’an 710049China Shaanxi Smart Networks and Ubiquitous Access Research Center Xi’an 710049China

In this paper, we focus on the pilot-assisted transmission design for downlink URLLC over nonreciprocal channels, in which the multi-antenna controller sends mission-critical data signals to a singleantenna actuator. In this system, the prior knowledge of downlink channel state information(CSI) is a prerequisite for reliable data transmission. Generally, the acquisition of downlink CSI is completed either via the uplink pilot measurement exploiting channel reciprocity and time-division duplex(TDD) operation, or via the downlink pilot measurement with quantized feedback and frequency division duplex(FDD) operation. Inspired by this, we aim to investigate how the degree of channel non-reciprocity impacts the transmission reliability of our URLLC system, and the superiority between the TDD mode and FDD mode in terms of transmission reliability maximization. To describe the degree of reliability loss, we derive the closed-form approximations on the transmission error probability of URLLC in TDD and FDD modes, via leveraging the Gauss-Hermite and Gauss-Chebyshev quadrature rules. Following by the theoretical approximations, we demonstrate how to determine the optimal training pilot length and quantized feedback duration that maximize the transmission reliability under given latency constraint. Through numerical results,we validate the accuracy of theoretical approximations derived in this paper, and obtain some meaningful conclusions.

关键词： URLLC channel non-reciprocity channel training quantized feedback Gaussian quadrature

Radio Frequency Fingerprinting Identification Using Semi-Supervised Learning with Meta Labels

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China Communications 2023年第12期20卷 78-95页

作者： Tiantian Zhang pinyi ren Dongyang Xu Zhanyi ren School of Information and Communications Engineering Xi’an Jiaotong UniversityXi’an 710049China Shaanxi Smart Networks and Ubiquitous Access Research Center Xi’an 710049China

Radio frequency fingerprinting(RFF)is a remarkable lightweight authentication scheme to support rapid and scalable identification in the internet of things(IoT)*** learning(DL)is a critical enabler of RFF identification by leveraging the hardware-level ***,traditional supervised learning methods require huge labeled training ***,how to establish a highperformance supervised learning model with few labels under practical application is still *** address this issue,we in this paper propose a novel RFF semi-supervised learning(RFFSSL)model which can obtain a better performance with few meta ***,the proposed RFFSSL model is constituted by a teacher-student network,in which the student network learns from the pseudo label predicted by the ***,the output of the student model will be exploited to improve the performance of teacher among the labeled ***,a comprehensive evaluation on the accuracy is *** derive about 50 GB real long-term evolution(LTE)mobile phone’s raw signal datasets,which is used to evaluate various *** results demonstrate that the proposed RFFSSL scheme can achieve up to 97%experimental testing accuracy over a noisy environment only with 10%labeled samples when training samples equal to 2700.

关键词： meta labels parameters optimization physical-layer security radio frequency fingerprinting semi-supervised learning

Semi-Supervised Learning Based Big Data-Driven Anomaly Detection in Mobile Wireless Networks

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China Communications 2018年第4期15卷 41-57页

作者： bilal hussain qinghe du pinyi ren department of information and communications engineering xi'an jiaotong universityXi’anShaanxi Province 710049China shaanxi smart networks and ubiquitous access research center xi'an jiaotong universityXi’anShaanxi Province 710049China

With rising capacity demand in mobile networks, the infrastructure is also becoming increasingly denser and complex. This results in collection of larger amount of raw data(big data) that is generated at different levels of network architecture and is typically underutilized. To unleash its full value, innovative machine learning algorithms need to be utilized in order to extract valuable insights which can be used for improving the overall network's performance. Additionally, a major challenge for network operators is to cope up with increasing number of complete(or partial) cell outages and to simultaneously reduce operational expenditure. This paper contributes towards the aforementioned problems by exploiting big data generated from the core network of 4 G LTE-A to detect network's anomalous behavior. We present a semi-supervised statistical-based anomaly detection technique to identify in time: first, unusually low user activity region depicting sleeping cell, which is a special case of cell outage; and second, unusually high user traffic area corresponding to a situation where special action such as additional resource allocation, fault avoidance solution etc. may be needed. Achieved results demonstrate that the proposed method can be used for timely and reliable anomaly detection in current and future cellular networks.

关键词：机器学习算法无线网络数据驱动监督活动网络基础结构 tial 核心网络

Towards win-win: weighted-Voronoi-diagram based channel quantization for security enhancement in downlink cloud-RAN with limited CSI feedback

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Science China(Information Sciences) 2017年第4期60卷 32-48页

作者： Dongyang XU pinyi ren Qinghe DU Li SUN Yichen WANG School of Electronic and Information Engineering Xi'an Jiaotong University

Physical layer(PHY) security is recently proved to enable improving the security of wireless communication networks. In downlink frequency division duplex(FDD) cloud radio access network(C-RAN), the performance of PHY security highly relies on the channel state information(CSI) which is usually acquired through the codebook-quantization-based technique at the transceiver. However, the conventional quantization method aggravates the leakage of privacy information in C-RAN under the eavesdropping environment. In this paper, a novel channel quantization method is investigated to improve the secrecy-rate performance of C-RAN by exploiting the high-dimension space geometry. Based on this method, it is proved that when the statistical distribution of the channel matrices of both the legitimate user and the eavesdropper is exploited, a win-win situation can be created where secrecy-rate gains are improved without sacrificing beamforming gains from the point of view of ergodic rate. Particularly, a secrecy-oriented criterion is devised to implement the proposed method for generating codebooks. Then a weighted Voronoi diagram(WVD) is formulated on the complex Grassmann manifold and finally, a vector quantization based algorithm is proposed to build up novel quantization codebooks iteratively. Simulation results further validate the superiority of our proposed codebooks over conventional codebooks in C-RAN systems.

关键词： C-RAN virtualization physical layer security Grassmann manifold channel quantization

Joint Dynamic Clustering and User Scheduling for Downlink Cloud Radio Access Network with Limited Feedback

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China Communications 2015年第12期12卷 147-159页

作者： XU Dongyang ren pinyi DU Qinghe SUN Li Ministry of Education Key Lab For Intelligent Networks and Network Security of Xi'an Jiaotong University Department of Information and Communications Engineering School of Electronic and Information EngineeringXi'an Jiaotong University

In limited feedback-based CloudRAN(C-RAN) systems,the inter-cluster and intra-cluster interference together with the quantification error can seriously deteriorates the system spectral ***,in this paper,propose an efficient three-phase framework and corresponding algorithms for dealing with this ***,a greedy scheduling algorithm based on the lower bound of the ergodic rate is performed for generating an elementary cluster in the first *** then the elementary cluster is divided into many small clusters according to the following proposed algorithms based on the short term instantaneous information in the second *** the end,based on the limited feedback two zero-forcing(ZF) precoding strategies are adopted for reducing the intra-cluster interference in the third *** provided Monte Carlo simulations show the effectiveness of our proposed algorithms in the respect of system spectral efficiency and average user rate.

关键词：调度算法无线接入网动态聚类反馈用户节点蒙特卡罗模拟频谱效率

A CHANNEL ASSIGNMENT ALGORITHM VIA CONFLICT SHIFTING FOR DISTRIBUTED COGNITIVE NETWORKS

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Journal of Electronics(China) 2010年第5期27卷 647-654页

作者： Gong Minkang ren pinyi Department of Electronic Engineering Xi＇an Jiaotong UniversityXi＇an 710049China

Channel assignment is a challenge for distributed cognitive networks due to spectrum mobility and lack of centralized *** present a dynamic and efficient algorithm via conflict shifting,referred as Shifting-based Channel Assignment(SCA).In this algorithm,the system was modeled with a conflict graph,and users cannot assign the channels that primary users(legacy users) and neighbors already *** order to eliminate the conflicts between neighbors efficiently,secondary users(unlicensed users) try to transfer them through a straight path to the boundary,where conflicts are easier to solve as there are less neighbors for boundary *** in one shift are executed in slots,and users act in a synchronous and separated *** a result,some of the conflicting channels are avoid from directly abandoned,and for this,utility of the entire network can be *** results show that the proposed algorithm can provide similar utility performance while obviously reducing the communication cost than bargaining-base *** small scale networks with low user mobility(under 20%),it reduces 50% of the communication overhead than the later.

关键词： Distributed cognitive network channel assignment Shifting-based Channel Assignment (SCA)

AN EFFECTIVE SUBOPTIMAL POWER LOADING SCHEME IN OFDM-BASED COGNITIVE RADIO SYSTEMS

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Journal of Electronics(China) 2010年第5期27卷 655-663页

作者： Yan Shuangcheng ren pinyi Hu Wenquan Department of Electronics and Information Engineering Xi＇an Jiaotong UniversityXi＇an 710049China

Orthogonal frequency division multiplexing(OFDM) is an attractive modulation candidate for Cognitive Radio(CR) *** and reliable subcarrier power allocation in OFDM-based Cognitive Radio(CR) networks is a challenging *** paper focuses on the power allocation for OFDM-based Cognitive Radio(CR) *** objective is to maximize the total transmission rates of Secondary Users(SU) by adjusting the power of subcarrier while the interference introduced to the Primary User(PU) is within a certain range and the total power of subcarrier is not beyond the total power *** investigate the optimal power allocation algorithm for OFDM-based Cog-nitive Radio(CR) based on convex optimization ***,because of high complexity of the op-timal power allocation algorithm,we propose an effective suboptimal power loading *** analysis and simulation results show that the performance of the suboptimal power allocation algorithm is close to the performance of the optimal power allocation algorithm,while the complexity of the suboptimal power allocation algorithm is much lower.

关键词： Orthogonal Frequency Division Multiplexing (OFDM) Cognitive Radio (CR) Power allocation

A DYNAMIC SPECTRUM ACCESS NETWORK BASED ON COGNITIVE RADIO

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Journal of Electronics(China) 2010年第5期27卷 577-610页

作者： ren pinyi Wang Jun Li Shaoqian Department of Electronics and Information Engineering Xi＇an Jiaotong UniversityXi＇an 710049China

Dynamic spectrum access technologies based on Cognitive Radio(CR) is under intensive research carried out by the wireless communication society and is expected to solve the problem of spectrum ***,most enabling technologies related to dynamic spectrum access are con-sidered *** this paper,we consider these key technologies jointly and introduce a new implementation scheme for a Dynamic Spectrum Access Network Based on Cognitive Radio(DSAN-BCR).We start with a flexible hardware platform for DSAN-BCR,as well as a flexible protocol structure that dominates the operation of *** then focus on the state of the art of key technologies such as spectrum sensing,spectrum resources management,dynamic spectrum access,and routing that are below the network layer in DSAN-BCR,as well as the development of technologies related to higher *** but not the least,we analyze the challenges confronted by these men-tioned technologies in DSAN-BCR,and give the perspectives on the future development of these *** DSAN-BCR introduced is expected to provide a system level guidance to alleviate the problem of spectrum scarcity.

关键词： Cognitive Radio (CR) Dynamic Spectrum Access Network Based on Cognitive Radio (DSAN-BCR) Spectrum sensing Spectrum management Dynamic Spectrum Access (DSA) Cognitive routing

A directional MAC protocol with long-range communication ability in ad hoc networks

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Science China(Information Sciences) 2012年第4期55卷 765-777页

作者： ren pinyi,FENG Jia & WANG YiChen School of Electronics and Information Engineering,Xi’an Jiaotong University,Xi’an 710049,China School of Electronics and Information Engineering Xi"an Jiaotong University

To address the problem that long-range communication capability in ad hoc networks using directional antenna is not generally utilized,a directional media access control (DMAC) protocol with long-range communication (LRC) capability in ad hoc networks is *** the LRC-DMAC,the intermediate node uses a long-range orientation (LRO) algorithm to help the transmitter obtain the directional information of the receiver which is two hops ***,the long-range link between such two hops nodes can be set *** to whether the received power information is available or not,we propose two types of LRO algorithm:without the received power information,a basic LRO obtains the approximate directional informa-tion of the long-range receiver by a geometric relationship;however,the LRO-PI can calculate the accurate directional information of the long-range receiver using the received *** analysis indicates that the LRO algorithm achieves high accuracy when the relevant parameters are properly *** results show that the establishment of long-range links can effectively improve the network throughput and reduce the end-to-end delay.

关键词： ad hoc networks directional antenna MAC