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An Isotropic SPPP Model for Femtocells networks with Outage Probability Constraints

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Chinese Journal of Electronics 2015年第4期24卷 824-831页

作者： ZHANG Jun TIAN Hui State Key laboratory of Networking and switching technology Beijing University of Posts and Telecommunication

Femtocells have been considered as a costeffective solution to unload traffic from already overburdened macrocell networks in 4G cellular networks. The severe interference in spectrum-sharing macro and femto networks may cause User-equipment(UE) to experience outage. We derive an utmost isotropic Spatial Poisson point process(SPPP) density for Femtocell access points(FAPs) under the UEs’ outage constraints. Based on the derived isotropic SPPP density, we propose a distributed transmit probability self-regulation scheme for an FAP to adapt its transmit probability per Transmission time interval(TTI). The scheme adjusts the homogeneous distributed FAPs in practice deployment to the proposed isotropic one. Simulation results show that the derived density can fulfill the outage probability constraints of UEs while accommodating the maximum femtocells. The selfregulation scheme can adapt the femtocell transmit probabilities to provide reliable downlink service, for even a large number of femtocells per cell site.

关键词： Heterogeneous network Stochastic geometry Outage probability

Developing Transparent IDS for VANETs Using LIME and SHAP:An Empirical Study

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Computers, Materials & Continua 2023年第12期77卷 3185-3208页

作者： Fayaz Hassan Jianguo Yu Zafi Sherhan Syed Arif Hussain Magsi Nadeem Ahmed Beijing Key laboratory of Work Safety Intelligent Monitoring School of Electronic EngineeringBeijing University of Post and TelecommunicationBeijing100876China Department of telecommunication Engineering Mehran University of Engineering and TechnologyJamshoro76062Pakistan State Key laboratory of Networking and switching technology Beijing University of Post and TelecommunicationBeijing100876China School of Electronic Science Beijing University of Post and TelecommunicationBeijing100876China

Vehicular Ad-hoc networks(VANETs)are mobile ad-hoc networks that use vehicles as nodes to create a wireless network.Whereas VANETs offer many advantages over traditional transportation networks,ensuring security in VANETs remains a significant challenge due to the potential for malicious attacks.This study addresses the critical issue of security in VANETs by introducing an intelligent Intrusion Detection System(IDS)that merges Machine Learning(ML)–based attack detection with Explainable AI(XAI)explanations.This study ML pipeline involves utilizing correlation-based feature selection followed by a Random Forest(RF)classifier that achieves a classification accuracy of 100%for the binary classification task of identifying normal and malicious traffic.An innovative aspect of this study is the incorporation of XAI methodologies,specifically the Local Interpretable Model-agnostic Explanations(LIME)and SHapley Additive exPlanations(SHAP).In addition,this research also considered key features identified by mutual information-based feature selection for the task at hand.The major findings from this study reveal that the XAI-based intrusion detection methods offer distinct insights into feature importance.Key features identified by mutual information,LIME,and SHAP predominantly relate to Transmission Control Protocol(TCP),Hypertext Transfer Protocol(HTTP),Domain Name System(DNS),and Message Queuing Telemetry Transport(MQTT)protocols,highlighting their significance in distinguishing normal and malicious network activity.This XAI approach equips cybersecurity experts with a robust means of identifying and understanding VANET malicious activities,forming a foundation for more effective security countermeasures.

关键词： Intrusion detection system machine learning security vehicular networks

In-network caching for energy efficiency in content-centric networking

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The Journal of China Universities of Posts and telecommunications 2014年第4期21卷 25-31页

作者： WANG Guo-qing HUANG Tao LIU Jiang XIE Ren-chao LIU Yun-jie State Key laboratory of Networking and switching technology School of Telecommunication EngineeringBeijing University of Posts and Telecommunications

Recently, Internet energy efficiency is paid more and more attention. New Internet architectures with more energy efficiency were proposed to promote the scalability in energy consumption. The eontent-eentrie networking （CCN） proposed a content-centric paradigm which was proven to have higher energy efficiency. Based on the energy optimization model of CCN with in-network caching, the authors derive expressions to tradeoff the caching energy and the transport energy, and then design a new energy efficiency cache scheme based on virtual round trip time （EV） in CCN. Simulation results show that the EV scheme is better than the least recently used （LRU） and popularity based cache policies on the network average energy consumption, and its average hop is also much better than LRU policy.

关键词： CCN EV cache scheme energy efficiency

Improving SINR via Joint Beam and Power Management for GEO and LEO Spectrum-Sharing Satellite Communication Systems

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China Communications 2022年第7期19卷 25-36页

作者： Xiaojin Ding Zhuangzhuang Ren Huanbin Lu Gengxin Zhang telecommunication and networks national Engineering Research Center Nanjing University of Posts and TelecommunicationsNanjing 210003China

In this paper,we investigate a geosynchronous earth orbit(GEO)and low earth orbit(LEO)coexisting satellite communication system.To decrease the interference imposed on the GEO user caused by LEO satellites,we propose a joint beammanagement and power-allocation(JBMPA)scheme to maximize signal-to-interference plus noise ratio(SINR)at the GEO user,whilst maintaining the ongoing wireless links spanning from LEO satellites to their corresponding users.Specifically,we first analyze the overlapping coverage among GEO and LEO satellites,to obtain the LEO-satellite set in which their beams impose interference on the GEO user.Then,considering the traffic of LEO satellites in the obtained set,we design a beam-management method to turn off and switch interference beams of LEO satellites.Finally,we further propose a deep Q-network(DQN)aided power allocation algorithm to allocate the transmit power for the ongoing LEO satellites in the obtained set,whose beams are unable to be managed.Numerical results show that comparing with the traditional fixed beam with power allocation(FBPA)scheme,the proposed JBMPA can achieve a higher SINR and a lower outage probability,whilst guaranteeing the ongoing wireless transmissions of LEO satellites.

关键词： beam management deep Q-network GEO-LEO coexisting power allocation

A Recursive DRL-based Resource Allocation Method for Multibeam Satellite Communication Systems

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Chinese Journal of Electronics 2023年

作者： Haowei MENG Ning XIN Hao QIN Di ZHAO the China Academy of Space technology Institute of Telecommunication Satellite the State Key laboratory of Integrated Services networks Xidian University

Optimization-based radio resource management (RRM) has shown significant performance gains on high-throughput satellites (HTSs). However, as the number of allocable on-board resources increases, traditional RRM are difficult to apply in real satellite systems due to its intense computational complexity. DRL is a promising solution for the resource allocation problem due to its model-free advantages. Nevertheless, the action space faced by DRL increases exponentially with the increase of communication scale, which leads to an excessive exploration cost of the algorithm. In this paper, we propose a recursive frequency resource allocation algorithm based on long-short term memory (LSTM) and proximal policy optimization (PPO), called PPO-RA-LOOP, where RA means resource allocation and LOOP means the algorithm outputs actions in a recursive manner. Specifically, the PPO algorithm uses LSTM network to recursively generate sub-actions about frequency resource allocation for each beam, which significantly cut down the action space. In addition, the LSTM-based recursive architecture allows PPO to better allocate the next frequency resource by using the generated sub-actions information as a prior knowledge, which reduces the complexity of the neural network. The simulation results show that PPO-RA-LOOP achieved higher spectral efficiency and system satisfaction compared with other frequency allocation algorithms.

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Secure Beamforming Design for SWIPT in Cooperative D2D Communications

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China Communications 2017年第1期14卷 20-33页

作者： Li Jiang Cheng Qin Xixi Zhang Hui Tian State Key laboratory of Networking and switching technology Beijing University of Posts and Telecommunicationsand Science and Technology on Information Transmission and Dissemination in Communication Networks LaboratoryBeijing100876China

In device-to-device(D2D) communications, device terminal relaying makes it possible for devices in a network to function as transmission relays for each other to enhance the spectral efficiency. In this paper we consider a cooperative D2D communication system with simultaneous wireless information and power transfer(SWIPT). The cooperative D2D communication scheme allows two nearby devices to communicate with each other in the licensed cellular bandwidth by assigning D2D transmitters as half-duplex(HD) relay to assists cellular downlink transmissions. In particular, we focus on secure information transmission for the cellular users when the idle D2D users are the potential eavesdroppers. We aim to design secure beamforming schemes to maximize the D2D users data rate while guaranteeing the secrecy rate requirements of the cellular users and the minimum required amounts of power transferred to the idle D2D users. To solve this non-convex problem, a semi-definite programming relaxation(SDR) approach is adopted to obtain the optimal solution. Furthermore, we propose two suboptimal secure beamforming schemes with low computational complexity for providing secure communication and efficient energy transfer. Simulation results demonstrate the superiority of our proposed scheme.

关键词： device-to-device(D2D) communications half-duplex relaying physical layer security secure beamforming simultaneous wireless information and power transfer

A Dynamic Protocol Stack Structure for Diversified QoS Requirements in Ad Hoc Network

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China Communications 2016年第S1期13卷 43-53页

作者： DONG Fang Li Ou RAN Xiaomin JIN Feicai national Digital switching System Engineering & Technological Research Center Zhongxing telecommunication Equipment Corporation

A dynamic protocol stack(DPS) for ad hoc networks, together with a protocol stack construction scheme that is modeled as a multiconstrained knapsack problem is proposed. Compared to the traditional static protocol stack, DPS operates in a dynamic and adaptive manner and is scalable to network condition changes. In addition, a protocol construction algorithm is proposed to dynamically construct of the protocol stack each network node. Simulation results show that, the processing and forwarding performance of our scheme is close to 1 Gb/s, and the performance of our algorithm is close to that of the classical algorithms with much lower complexity.

关键词： ad hoc network QoS guarantee dynamic protocol stack protocol construction algorithm

A DTN Oriented Adaptive Routing Algorithm Based on Node Load

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China Communications 2022年第12期19卷 54-63页

作者： Hongyan Cui Diyue Chen Roy E.Welsch State Key laboratory of Networking and switching technology Beijing University of Posts and TelecommunicationsBeijing 100876China Beijing laboratory of Advanced Information networks Beijing University of Posts and TelecommunicationsBeijing 100876China Massachusetts Institute of technology CambridgeMA 02139USA

In recent years,Delay Tolerant networks(DTN)have received more and more attention.At the same time,several existing DTN routing algorithms generally have disadvantages such as poor scalability and inability to perceive changes in the network environment.This paper proposes an AdaptiveSpray routing algorithm.The algorithm can dynamically control the initial maximum message copy number according to the cache occupancy rate of the node itself,and the cache occupancy rate is added as an impact factor to the calculation of the probability of each node meeting the destination node.In the forwarding phase,the node will first compare the meeting probability of itself and the meeting node to the destination node,and then choose different forwarding strategies.The simulation shows that the AdaptiveSpray algorithm proposed in this paper has obvious advantages compared with the existing routing algorithms in terms of message delivery rate and average delay.

关键词： DTN routing algorithm adaptive cache management

Garbage Collection in Uncoordinated Checkpointing Algorithms

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Journal of Computer Science & technology 1999年第3期14卷 242-244页

作者：刘云龙陈俊亮 National Laboratory of Switching Technology and Telecommunication Networks Beijing University of Posts and Telecommunications Beijing P.R. China

In this papert the hard problem of the thorough garbage collection in uncoordinated Checkpointing algorithms is studied. After introduction of the traditional garbage collecting scheme, with which only obsolete checkpoints can be discarded, it is shown that this kind of traditional method may fail to discard any checkpoint in some special cases, and it is necessary and urgent to find a thorough garbage collecting method, with which all the checkpoints useless for any future rollback-recovery including the obsolete ones can be discarded. Then, the Thorough Garbage Collection Theorem is proposed and proved, which ensures the feasibility of the thorough garbage collection, and gives the method to calculate the set of the useful checkpoints as well.

关键词： distributed system checkpointing and rollback recovery storage management thorough garbage collection