期刊文献+
共找到52篇文章
< 1 2 3 >
每页显示 20 50 100
Security analysis of newly ameliorated WAPI protocol 被引量:3
1
作者 庞辽军 李慧贤 王育民 《Journal of Southeast University(English Edition)》 EI CAS 2008年第1期25-28,共4页
Based on thorough researches on the Chinese wireless local area network (WLAN) security standard, i. e., WLAN authentication and privacy infrastructure (WAPI), the security of the authentication access process is ... Based on thorough researches on the Chinese wireless local area network (WLAN) security standard, i. e., WLAN authentication and privacy infrastructure (WAPI), the security of the authentication access process is analyzed with the CK (Canetti-Krawczyk) model and the BAN (Burrows-Abadi- Needham) logic. Results show that it can achieve the alleged authentication and key negotiation goals. Besides those alleged, further analyses indicate that the authentication access process can satisfy other security requirements, such as mutual identity authentication, mutual key control, key confirmation, message integrity check, etc. If the used elliptic curve encryption algorithm and the hash algorithm are secure enough, the protocol can efficiently realize mutual authentication between STAs (station) and APs (access point). Therefore, WAPI can be applied to replace the security mechanism used in the original WLAN international standard to enhance its security. 展开更多
关键词 wireless local area network (WLAN) WLAN authentication and privacy infrastructure (WAPI) AUTHENTICATION key negotiation CK model
下载PDF
MODIFIED ULTRA WIDEBAND CIRCULAR PRINTED MONOPOLE ANTENNA 被引量:4
2
作者 何小祥 邓宏伟 《Transactions of Nanjing University of Aeronautics and Astronautics》 EI 2008年第3期214-218,共5页
A simple and compact microstrip-fed ultra wideband (UWB) printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz abso... A simple and compact microstrip-fed ultra wideband (UWB) printed monopole antenna is presented. The antenna is composed of a circular radiator and a finitely grounded plane. The antenna occupies about 16.62 GHz absolute bandwidth and 142.7% relative bandwidth covering from 3.38 GHz to 20 GHz with voltage standing wave ratio (VSWR) below two. A quasi-omnidirectional and quasi-symmetrical radiation pattern in H plane is obtained in the whole bandwidth. The high performance of the antenna is validated with measured and simulated results given. The antenna can be applied for the system design of UWB wireless communication. 展开更多
关键词 microstrip antennas wireless local area network (WLAN) mobile antennas ultra wideband(UWB) printed antenna
下载PDF
CMOS Mixers for 2.4GHz WLAN Transceivers 被引量:2
3
作者 池保勇 石秉学 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第5期472-475,共4页
A down-conversion mixer and an up-conversion mixer for 2.4GHz WLAN transceivers are presented.The down-conversion mixer uses a class-AB input stage to get high linearity and to realize input impedance matching and sin... A down-conversion mixer and an up-conversion mixer for 2.4GHz WLAN transceivers are presented.The down-conversion mixer uses a class-AB input stage to get high linearity and to realize input impedance matching and single-ended to differential conversion.The mixers are implemented in 0.18μm CMOS process.The measured results are given to show their performance. 展开更多
关键词 WLAN transceivers MIXER Gilbert cell
下载PDF
Integrated Low-Power CMOS VCO and Its Divide-by-2 Dividers 被引量:1
4
作者 池保勇 石秉学 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2002年第12期1262-1266,共5页
An integrated low power CMOS VCO and its divide by 2 dividers for WLAN transceivers are presented.The VCO is based on on chip symmetrical spiral inductor and differential diode and the divide by 2 dividers are b... An integrated low power CMOS VCO and its divide by 2 dividers for WLAN transceivers are presented.The VCO is based on on chip symmetrical spiral inductor and differential diode and the divide by 2 dividers are based on the ILFD technique.Due to differential LC tanks and ILFD techniques,power consumption is low.The circuit is implemented in a 0 18μm CMOS process.Measurements show the proposed circuit could produce 3 6/1 8GHz dual band LO signals with a wide tuning range and low phase noise.1 8GHz LO signals are quadrature.It consumes 5mA at V DD =1 5V.The size of die area is only 1 0mm×1 0mm. 展开更多
关键词 VCO WLAN transceivers divide by 2 divider
下载PDF
A Low Noise,High Linearity CMOS Receiver for 802.11b WLAN Applications
5
作者 黄煜梅 王静光 +1 位作者 王金菊 洪志良 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2008年第9期1708-1714,共7页
A 2.4GHz monolithic CMOS receiver with direct-conversion architecture is presented. This quadrature receiver is designed for 802.11b wireless LAN applications at the maximum data rate of 11Mbps as a low-cost solution.... A 2.4GHz monolithic CMOS receiver with direct-conversion architecture is presented. This quadrature receiver is designed for 802.11b wireless LAN applications at the maximum data rate of 11Mbps as a low-cost solution. Five key blocks,i, e., a low noise amplifier (LNA), a down-conversion mixer, a variable gain amplifier, a low pass filter, and a DC- offset cancellation circuit,are designed based on system design and low noise high linearity considerations. The necessary auxiliary circuits are also included. Fabricated in SMIC 0.18μm 1p6m RF CMOS process, the receiver's performance is measured as:4. 1 dB noise figure, - 7.5dBm input third order intercept point (IIP3) for LNA & mixer at high gain setting, - 14dBm IIP3 for the whole receiver,53dBc @30MHz offset of adjacent channel power rejection,and less than 5mV out- put DC-offset. The receiver consumes 44mA under a 1.8V power supply with I,Q two paths. 展开更多
关键词 802.11b wireless LAN RECEIVER DC-offset cancellation MIXER
下载PDF
物联网智能空调用WiFi无线通信模块应用可靠性分析 被引量:6
6
作者 尹粤卿 《电子产品世界》 2021年第4期32-35,共4页
WiFi无线通信模块应用出现大比例失效,问题类别多,断断续续下线一年没有得到彻底解决,严重影响产品质量。经过对大量模块进行深入分析,发现均为模块制造及设计问题导致长期大批量下线,通过研究最终找到了有效解决方案,从器件本身制造及... WiFi无线通信模块应用出现大比例失效,问题类别多,断断续续下线一年没有得到彻底解决,严重影响产品质量。经过对大量模块进行深入分析,发现均为模块制造及设计问题导致长期大批量下线,通过研究最终找到了有效解决方案,从器件本身制造及设计存在问题着手采取有效措施解决问题。 展开更多
关键词 物联网 WiFi模块 短路 无局域网
下载PDF
Key Techniques of Frequency Synthesizer for WLAN Receivers
7
作者 唐路 王志功 +1 位作者 徐勇 李智群 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2007年第4期542-548,共7页
Several key techniques for a PLL-type frequency synthesizer for WLAN receivers are studied. Its structure is analyzed and the main parameters are proposed. A monolithic LC-tuned voltage controlled oscillator (LCVCO)... Several key techniques for a PLL-type frequency synthesizer for WLAN receivers are studied. Its structure is analyzed and the main parameters are proposed. A monolithic LC-tuned voltage controlled oscillator (LCVCO) with low phase noise is fabricated with TSMC 0.18μm RF (radio frequency) CMOS technology. The measured phase noise is - ll7dBc/Hz at 4MHz off the center frequency of 4. 189GHz. A down-scaling circuit with low power dissipation was fabricated in a TSMC 0.18μm mixed-signal CMOS process. The measured results show that the IC can work well under a 1.8V power supply. Its total power dissipation is only 13mW. 展开更多
关键词 PLL WLAN VCO down scaling
下载PDF
A CMOS high-IF down-conversion mixer for WLAN 802.11a applications
8
作者 张浩 李智群 王志功 《Journal of Southeast University(English Edition)》 EI CAS 2010年第1期11-16,共6页
A low noise, high conversion gain down-conversion mixer for WLAN 802.11a applications, which adopts the high intermediate frequency (IF) topology, is presented. The input radio frequency (RF)band, local oscillator... A low noise, high conversion gain down-conversion mixer for WLAN 802.11a applications, which adopts the high intermediate frequency (IF) topology, is presented. The input radio frequency (RF)band, local oscillator(LO)frequency band and output IF are 5.15 to 5.35, 4.15 to 4.35 and 1 GHz, respectively. Source resistive degeneration technique and pseudo-differential Gilbert topology are used to achieve high linearity, and, current bleeding technique and LC resonant loads are used to acquire a low noise figure. In addition, the mixer adopts a common-source transistor pair cross-stacked with a source follow pair(CSSF)circuit as an output buffer to enhance the mixer's conversion gain but not deteriorate the other performances. The mixer is implemented in 0.18 μm RF CMOS(complementary metal oxide semiconductor transistor)technology and the chip area of the mixer including all bonding pads is 580 μm×1 185 μm. The measured results show that under a 1.8 V supply, the conversion gain is 10.1 dB; the input 1 dB compression point and the input-referred third-order intercept point are-3.5 and 5.3 dBm, respectively; the single side band (SSB)noise figure (NF)is 8.65 dB, and the core current consumption is 3.8 mA. 展开更多
关键词 high intermediate frequency MIXER high linearity WLAN 802.11a BUFFER complementary metal oxide semiconductor transistor(CMOS)
下载PDF
Performance enhancement of IEEE 802.11 distributed coordination function for MANET
9
作者 翟旭平 毕光国 徐平平 《Journal of Southeast University(English Edition)》 EI CAS 2004年第4期418-422,共5页
The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adapti... The medium access control (MAC) issue was discussed in mobile Ad Hoc networks (MANETs). Based on the IEEE 802.11 MAC protocol, this paper proposed two schemes, the forward-packet-first (FPF) scheme based on the adaptive backoff contention window and multihop forward chain transmission by invitation (MFCTI) scheme. In the FPF scheme, the contention window was adjusted adaptively according to the traffic priority. Route information and the broadcast characteristic of radio were utilized in MFCTI scheme. The performance of these schemes was studied in multihop environments by simulations. The results showed that the proposed schemes could improve the network throughput, reduce the end-to-end average delay, and mitigate local congestion effectively. Another attractive feature was that the schemes could be implemented with minor modifications to the IEEE 802.11 MAC. 展开更多
关键词 Adaptive systems Packet networks Radio broadcasting ROUTERS
下载PDF
MAC isolation to realize effective management in public wireless LAN
10
作者 陈立全 胡爱群 计文柯 《Journal of Southeast University(English Edition)》 EI CAS 2004年第2期157-161,共5页
This paper describes how to use medium access control (MAC) isolation to enhance management performance in public wireless LAN (PWLAN). To comply with the IEEE 802.11 standards, a scheme to implement MAC isolation in ... This paper describes how to use medium access control (MAC) isolation to enhance management performance in public wireless LAN (PWLAN). To comply with the IEEE 802.11 standards, a scheme to implement MAC isolation in WLAN access points by re-designing the Distribution_Service component of the MAC state machine is proposed. A variable named dotl 1 Isolation is defined to determine whether the MAC level communication between wireless stations in the same BSS is permitted or not. Finally, a design solution based on MPC860 hardware and embedded Linux software for PWLAN access point is specified. The simulation results of MAC isolation for PWLAN show that the proposed scheme is feasible and effective. 展开更多
关键词 Codes (standards) Computer operating systems Computer simulation Network protocols Wireless telecommunication systems
下载PDF
A Gridless Router Based on Hierarchical PB Corner Stitching Structure
11
作者 张轶谦 蔡懿慈 +2 位作者 洪先龙 张雁 谢民 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2003年第2期141-147,共7页
A multi layer gridless area router is reported.Based on corner stitching,this router adopts tile expansion to explore path for each net.A heuristic method that penalizes nodes deviating from the destination is devise... A multi layer gridless area router is reported.Based on corner stitching,this router adopts tile expansion to explore path for each net.A heuristic method that penalizes nodes deviating from the destination is devised to accelerate the algorithm.Besides,an enhanced interval tree is used to manage the intermediate data structure.In order to improve the completion rate of routing,a new gridless rip up and rerouting algorithm is proposed.The experimental results indicate that the completion rate is improved after the rip up and reroute process and the speed of this algorithm is satisfactory. 展开更多
关键词 gridless area routing rip up and reroute corner stitching structure VLSI
下载PDF
Station based fast handoff solution for IEEE 802.11 b/g wireless LANs 被引量:4
12
作者 倪维国 董永强 夏勤 《Journal of Southeast University(English Edition)》 EI CAS 2008年第2期149-154,共6页
Real-time applications are sensitive to conditions such as transmission delay and jittering. To cut down on the influence generated by the WLAN handoff process, three parts of WLAN (wireless local area networks) han... Real-time applications are sensitive to conditions such as transmission delay and jittering. To cut down on the influence generated by the WLAN handoff process, three parts of WLAN (wireless local area networks) handoff: handoff triggering, access point selection and the fast handoff algorithm are investigated. A fast handoff solution totally based on the station is proposed and it is composed of three parts: a handoff triggering mechanism based on dynamic threshold adjustment; an AP selection criterion based on probe delay; a fast handoff algorithm with differentiated channel selection and a dynamic cache. The station based solution is independent with AP's collaboration and avoids any changes in the IEEE 802. l l protocol. It is robust and has very good extensibility. Through tests and evaluation in a hotspot WLAN, the solution effectively reduces handoff latency and user experience of real-time applications is enhanced. 展开更多
关键词 IEEE 802. 11 WLAN fast handoff
下载PDF
Generation of scale-free knowledge network with local world mechanism
13
作者 单海燕 王文平 《Journal of Southeast University(English Edition)》 EI CAS 2009年第4期545-548,共4页
In order to simulate the real growing process, a new type of knowledge network growth mechanism based on local world connectivity is constructed. By the mean-field method, theoretical prediction of the degree distribu... In order to simulate the real growing process, a new type of knowledge network growth mechanism based on local world connectivity is constructed. By the mean-field method, theoretical prediction of the degree distribution of the knowledge network is given, which is verified by Matlab simulations. When the new added node's local world size is very small, the degree distribution of the knowledge network approximately has the property of scale-free. When the new added node's local world size is not very small, the degree distribution transforms from pure power-law to the power-law with an exponential tailing. And the scale-free index increases as the number of new added edges decreases and the tunable parameters increase. Finally, comparisons of some knowledge indices in knowledge networks generated by the local world mechanism and the global mechanism are given. In the long run, compared with the global mechanism, the local world mechanism leads the average knowledge levels to slower growth and brings homogenous phenomena. 展开更多
关键词 knowledge network network structure SCALE-FREE local world mechanism
下载PDF
A DC-Offset Cancellation Scheme in a Direct-Conversion Receiver for IEEE 802.11a WLAN
14
作者 许奇明 石寅 +4 位作者 高鹏 胡雪青 颜峻 徐化 陈弘达 《Journal of Semiconductors》 EI CAS CSCD 北大核心 2006年第4期653-657,共5页
A DC-offset cancellation scheme in a 5GHz direct-conversion receiver compliant with the IEEE 802.11a wireless LAN standard is presented. An analog feedback loop is used to eliminate the DC-offset at the output of the.... A DC-offset cancellation scheme in a 5GHz direct-conversion receiver compliant with the IEEE 802.11a wireless LAN standard is presented. An analog feedback loop is used to eliminate the DC-offset at the output of the. double-balanced mixer. The test results show that the mixer with the DC-offset cancellation circuit has a voltage conversion gain of 9.5dB at 5.15GHz, a noise figure of 13.5dB, an IIP3 of 7.6dBm, a DC-offset voltage of 1.73mV eliminating 76% of DC-offset,and a power consumption of 67mW with a 3.3V supply. The direct conversion WLAN receiver has been implemented in 0.35μm SiGe BiCMOS technology. 展开更多
关键词 DC-offset WLAN BICMOS
下载PDF
Performance analysis of IEEE 802.11e EDCA in wireless LANs 被引量:7
15
作者 ZHANG Wei SUN Jun +1 位作者 LIU Jing ZHANG Hai-bin 《Journal of Zhejiang University-Science A(Applied Physics & Engineering)》 SCIE EI CAS CSCD 2007年第1期18-23,共6页
In this paper, we propose an analytical model for the performance evaluation of IEEE 802.1 le enhanced distributed channel access (EDCA). Different from most previous analytical studies based on the saturation assum... In this paper, we propose an analytical model for the performance evaluation of IEEE 802.1 le enhanced distributed channel access (EDCA). Different from most previous analytical studies based on the saturation assumption, we extend the analytical model to non-saturation conditions. An empty state is introduced into the Markov chain to represent the status of transmission queue being empty. This model can be used to calculate the traffic priority, throughput, and MAC layer delay with various configurations of contention parameters. A detailed simulation is provided to validate the proposed model. With the help of this model, the contention parameters can be configured appropriately to achieve specific quality-of-service (QoS) requirements. 展开更多
关键词 IEEE 802.11 e Saturation assumption Non-saturation assumption Enhanced distributed channel access (EDCA)
下载PDF
Energy Efficient Access Point Selection and Signal Projection for Accurate Indoor Positioning 被引量:5
16
作者 Deng Zhian Xu Yubin Ma Lin 《China Communications》 SCIE CSCD 2012年第2期52-65,共14页
We propose a method to improve positioning accuracy while reducing energy consumption in an indoor Wireless Local Area Network(WLAN) environment.First,we intelligently and jointly select the subset of Access Points(AP... We propose a method to improve positioning accuracy while reducing energy consumption in an indoor Wireless Local Area Network(WLAN) environment.First,we intelligently and jointly select the subset of Access Points(APs) used in positioning via Maximum Mutual Information(MMI) criterion.Second,we propose Orthogonal Locality Preserving Projection(OLPP) to reduce the redundancy among selected APs.OLPP effectively extracts the intrinsic location features in situations where previous linear signal projection techniques failed to do,while maintaining computational efficiency.Third,we show that the combination of AP selection and OLPP simultaneously exploits their complementary advantages while avoiding the drawbacks.Experimental results indicate that,compared with the widely used weighted K-nearest neighbor and maximum likelihood estimation method,the proposed method leads to 21.8%(0.49 m) positioning accuracy improvement,while decreasing the computation cost by 65.4%. 展开更多
关键词 indoor positioning energy efficientcomputing WLAN maximum mutual information orthogonal locality preserving projection
下载PDF
Design and development of WLAN access point based on Bluetooth and uClinux
17
作者 张磊 沈连丰 《Journal of Southeast University(English Edition)》 EI CAS 2004年第1期1-5,共5页
This paper describes the design and development of a wireless LAN (WLAN) access point based on Bluetooth and uClinux. To make the best use of high-speed serial communication capability, several methods such as modifyi... This paper describes the design and development of a wireless LAN (WLAN) access point based on Bluetooth and uClinux. To make the best use of high-speed serial communication capability, several methods such as modifying baud-rate of serial port driver, utilizing buffer area and adding flow-control were adopted. After analysis of scheduling and interruption handling, modifying the timer's parameters was put forward as a method to control the timer interrupt. In this way, data throughput and system stability were enhanced. Meanwhile, migration of the Bluetooth protocol stack was detailed and some successful applications of LAN access point were presented. 展开更多
关键词 Local area networks System stability
下载PDF
AN MAC PROTOCOL SUPPORTING MULTIPLE TRAFFIC OVER MOBILE AD HOC NETWORKS 被引量:2
18
作者 Tian Hui Li Yingyang Hu Jiandong Zhang Ping (College of Telecom. Eng., Beijing University of Posts & Telecommunications, Beijing 100876) 《Journal of Electronics(China)》 2003年第2期116-120,共5页
This letter presents the design and performance of a multi-channel MAC protocol that supports multiple traffics for IEEE 802.11 mobile ad-hoc networks. The dynamic channel selection scheme by receiver decision is impl... This letter presents the design and performance of a multi-channel MAC protocol that supports multiple traffics for IEEE 802.11 mobile ad-hoc networks. The dynamic channel selection scheme by receiver decision is implemented and the number of the data channel is independent of the network topology. The priority for real-time traffic is assured by the proposed adaptive back off algorithm and different IFS. The protocol is evaluated by simulation and the results have shown that it can support multiple traffics and the performance is better than the performance that IEEE 802.11 standard provides. 展开更多
关键词 Wireless networks Ad hoc wireless LAN Medium access control protocol
下载PDF
A Novel Vertical Handoff Algorithm with Dynamic Weights in Wireless Heterogeneous Networks 被引量:2
19
作者 Liu Xia Zhao Fangming Jiang Lingge 《China Communications》 SCIE CSCD 2010年第5期70-76,共7页
In order to enhance the quality of vertical handoff in an overlay wireless network, multiple attributes are taken into account when optimizing the vertical handoff decision including user-based and network-based QoS f... In order to enhance the quality of vertical handoff in an overlay wireless network, multiple attributes are taken into account when optimizing the vertical handoff decision including user-based and network-based QoS factors. In this paper, we develop a novel vertical handoff algorithm in an integrated 3G cellular and Wireless LAN networks. The proposed algorithm can adjust the weight of each QoS attribute dynamically as the networks change, trace the network condition and choose the optimal access point at transient regions. Simulation results show that this algorithm is able to provide accurate handoff decision, resulting in small unnecessary handoff numbers, good performance of throughput and handoff delay in heterogeneous environments. 展开更多
关键词 vertical handoff multiple attrbute dynamic weight heterogeneous networks
下载PDF
Domain adaptive methods for device diversity in indoor localization 被引量:1
20
作者 Liu Jing Liu Nan +1 位作者 Pan Zhiwen You Xiaohu 《Journal of Southeast University(English Edition)》 EI CAS 2019年第4期424-430,共7页
To solve the problem of variations in radio frequency characteristics among different devices,transfer learning is applied to transform device diversity to domain adaptation in the indoor localization algorithm.A robu... To solve the problem of variations in radio frequency characteristics among different devices,transfer learning is applied to transform device diversity to domain adaptation in the indoor localization algorithm.A robust indoor localization algorithm based on the aligned fingerprints and ensemble learning called correlation alignment for localization(CALoc)is proposed with low computational complexity.The second-order statistical properties of fingerprints in the offline and online phase are needed to be aligned.The real-time online calibration method mitigates the impact of device heterogeneity largely.Without any time-consuming deep learning retraining process,CALoc online only needs 0.11 s.The effectiveness and efficiency of CALoc are verified by realistic experiments.The results show that compared to the traditional algorithms,a significant performance gain is achieved and that it achieves better positioning accuracy with a 19%improvement. 展开更多
关键词 wireless local area networks indoor localization fingerprinting device diversity transfer learning correlation alignment
下载PDF
上一页 1 2 3 下一页 到第
使用帮助 返回顶部