Despite the rapid development in Worldwide Interoperability for Microwave Access (WiMAX) technologies,key technologies for the Physical Layer (PHY) still need to be further improved so as to achieve highly efficient a...Despite the rapid development in Worldwide Interoperability for Microwave Access (WiMAX) technologies,key technologies for the Physical Layer (PHY) still need to be further improved so as to achieve highly efficient and reliable communication performance,as well as to support a mobile environment with a higher transmisison rate. As an amendment to IEEE 802.16d (for fixed broadband wireless access systems),IEEE 802.16e (for mobile broadband wireless access systems) introduces the Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) technologies into the PHY,doubling the transmission rate while supporting a certain degree of mobility. In the future,more advanced Air Interface (AI) technology is to be applied in the IEEE 802.16m standard.展开更多
In this paper, a multiple parameters weighted fractional Fourier transform(MPWFRFT) and constellation scrambling(CS) method based physical layer(PHY) security system is proposed. The proposed scheme is executed by two...In this paper, a multiple parameters weighted fractional Fourier transform(MPWFRFT) and constellation scrambling(CS) method based physical layer(PHY) security system is proposed. The proposed scheme is executed by two steps. In the first step, MPWFRFT, implemented as the constellation beguiling(CB) method, is applied to change the signal's identity. In the second step the additional pseudo random phase information, regarded as the encryption key, is attached to the original signal to enhance the security. Typically, the pseudo random phase information can be removed effectively by the legitimate receiver. In contrast to the cryptography based encryption algorithms and the conventional PHY secrecy techniques, the main contribution of the proposed scheme is concentrated on the variation in signal's characteristics. Simulation results show that the proposed scheme can prevent the exchanging signal from eavesdroppers' classifi cation or inception. Moreover, the proposed scheme can guarantee the BER performance at a tolerate increasing in computational complexity for the legitimate receivers.展开更多
Wireless networks are playing an imperative role in our daily existence;in current scenario, the users want wireless connectivity for all location with all types of service. One of the major challenges for wireless ne...Wireless networks are playing an imperative role in our daily existence;in current scenario, the users want wireless connectivity for all location with all types of service. One of the major challenges for wireless network is security issue. First and foremost task is to detect the security attacks in the network and the second task is to prevent from an authorized attacks. In our view, a lot of researches are going on and somehow we have succeeded in the first case but the second task is very tough due to wireless channel. Our research is based on how to avoid network attack i.e. misbehavior node attack in the WiMAX system. In this paper we have proposed an algorithm for WiMAX network and our algorithm are able to prevent fixed as well as mobile misbehavior node attacks. As we know, misbehavior node misbehaves in the sense that the node does not esteem its MAC protocols and avariciously sends its packets without any restriction (Flooding of packets) because it doesn't follow any protocol. Our proposed work based on the standard time required for communication for valid user with some threshold time for valid delay and some unwanted delay with network conditions. Our approach can control continuous flooding of packets and continuously transmits Constant Bit Rate (CBR) packets by misbehavior node, which introduces noise in the network and upset the performance of the network. In the mean while the valid user communicate in a trouble-free approach.展开更多
In this paper we are given concept of our WiMAX (Worldwide Interoperability for Microwave Access) network perfor-mance for QoS monitoring and optimization solution for BS (Base Station) with multimedia application. In...In this paper we are given concept of our WiMAX (Worldwide Interoperability for Microwave Access) network perfor-mance for QoS monitoring and optimization solution for BS (Base Station) with multimedia application. In the communication sector, the optimal objective is to equate quality and cost. Due to its large coverage area, low cost of deployment and high speed data rates. WiMAX is a promising technology for providing wireless last-mile connectivity. Physical and MAC layer of this technology refer to the IEEE 802.16e standard, which defines 5 different data delivery service classes that can be used in order to satisfy Quality of Service (QoS) requirements of different applications, such as VoIP, videoconference, FTP, Web, etc. In this paper we have made six scenarios. Here two types of MAC layer QoS are used and they are UGS and rtPS having application of Voice over IP (VoIP) and MPEG respectively. Also the traffic priority for UGS is high as compared to rtPS. In each scenario the number of fixed nodes (Fixed Subscriber Stations) and Mobile nodes (Mobile Subscriber Stations) are different. To cover more nodes or if nodes are outside the coverage area more than one BS are required. All the simulation results based on optimized networks and area we have considered between Bhusaval and Jalgam.展开更多
单对线以太网是近年来新兴的以太网技术,随着汽车自动驾驶和工业物联网的高速发展,凭借上层应用扩展和底层布线上的绝对优势,正在大规模应用。单对线以太网物理层模拟前端技术是实现单对线以太网通信的关键基础技术。本文讲述了现有单...单对线以太网是近年来新兴的以太网技术,随着汽车自动驾驶和工业物联网的高速发展,凭借上层应用扩展和底层布线上的绝对优势,正在大规模应用。单对线以太网物理层模拟前端技术是实现单对线以太网通信的关键基础技术。本文讲述了现有单对线以太网物理层模拟前端相关的标准,架构及相关模块设计技术,重点对发射器TX和接收器RX关键模块的现有实现技术及其优缺点进行了列举分析。发射器TX电流模结构易于实现高精度但功耗效率低,电压模结构精度略低但功耗效率更高;接收器RX的设计围绕模拟数字转换器(Analog-to-Digital Converter,ADC)展开,ADC决定着整个RX的性能、功耗、面积和复杂度,分段和重新装配(Segmentation And Reassembly,SAR)ADC是首选结构,应用上限不断提高。由此进一步明确了在高性能、低功耗、小面积的单对线以太网物理层模拟前端设计中的挑战。展开更多
针对物理层抽象技术缺乏理论模型以及等效指数信噪比映射(EESM)物理层抽象算法依赖调整参数和通用性较差的缺点,依据信息论、信号检测和概率理论,提出了物理层抽象的概率模型,并据此推导得出基于平均互信息量的物理层抽象算法——块平...针对物理层抽象技术缺乏理论模型以及等效指数信噪比映射(EESM)物理层抽象算法依赖调整参数和通用性较差的缺点,依据信息论、信号检测和概率理论,提出了物理层抽象的概率模型,并据此推导得出基于平均互信息量的物理层抽象算法——块平均接收信息率(RBIR)算法。基于采用MIMO-OFDM技术和最小均方误差(MMSE)检测算法的WiMaxⅡ系统的仿真结果表明,对于ITU PedB 3kmph和ITU VA 30kmph信道模型、多种调制编码方式,该算法都能够获得与EESM算法相当的性能,并且不需要相关的调整参数,从而使得该算法更具一般性,能够较容易地扩展到不同的无线通信系统中,实现物理层抽象。该算法的有效性进一步验证了本文提出的物理层抽象概率模型。展开更多
文摘Despite the rapid development in Worldwide Interoperability for Microwave Access (WiMAX) technologies,key technologies for the Physical Layer (PHY) still need to be further improved so as to achieve highly efficient and reliable communication performance,as well as to support a mobile environment with a higher transmisison rate. As an amendment to IEEE 802.16d (for fixed broadband wireless access systems),IEEE 802.16e (for mobile broadband wireless access systems) introduces the Orthogonal Frequency Division Multiplexing (OFDM) and Multiple Input Multiple Output (MIMO) technologies into the PHY,doubling the transmission rate while supporting a certain degree of mobility. In the future,more advanced Air Interface (AI) technology is to be applied in the IEEE 802.16m standard.
基金supported by the National Basic Research Program of China under Grant 2013CB329003in part by the National Natural Science Foundation General Program of China under Grant 61171110
文摘In this paper, a multiple parameters weighted fractional Fourier transform(MPWFRFT) and constellation scrambling(CS) method based physical layer(PHY) security system is proposed. The proposed scheme is executed by two steps. In the first step, MPWFRFT, implemented as the constellation beguiling(CB) method, is applied to change the signal's identity. In the second step the additional pseudo random phase information, regarded as the encryption key, is attached to the original signal to enhance the security. Typically, the pseudo random phase information can be removed effectively by the legitimate receiver. In contrast to the cryptography based encryption algorithms and the conventional PHY secrecy techniques, the main contribution of the proposed scheme is concentrated on the variation in signal's characteristics. Simulation results show that the proposed scheme can prevent the exchanging signal from eavesdroppers' classifi cation or inception. Moreover, the proposed scheme can guarantee the BER performance at a tolerate increasing in computational complexity for the legitimate receivers.
文摘Wireless networks are playing an imperative role in our daily existence;in current scenario, the users want wireless connectivity for all location with all types of service. One of the major challenges for wireless network is security issue. First and foremost task is to detect the security attacks in the network and the second task is to prevent from an authorized attacks. In our view, a lot of researches are going on and somehow we have succeeded in the first case but the second task is very tough due to wireless channel. Our research is based on how to avoid network attack i.e. misbehavior node attack in the WiMAX system. In this paper we have proposed an algorithm for WiMAX network and our algorithm are able to prevent fixed as well as mobile misbehavior node attacks. As we know, misbehavior node misbehaves in the sense that the node does not esteem its MAC protocols and avariciously sends its packets without any restriction (Flooding of packets) because it doesn't follow any protocol. Our proposed work based on the standard time required for communication for valid user with some threshold time for valid delay and some unwanted delay with network conditions. Our approach can control continuous flooding of packets and continuously transmits Constant Bit Rate (CBR) packets by misbehavior node, which introduces noise in the network and upset the performance of the network. In the mean while the valid user communicate in a trouble-free approach.
文摘In this paper we are given concept of our WiMAX (Worldwide Interoperability for Microwave Access) network perfor-mance for QoS monitoring and optimization solution for BS (Base Station) with multimedia application. In the communication sector, the optimal objective is to equate quality and cost. Due to its large coverage area, low cost of deployment and high speed data rates. WiMAX is a promising technology for providing wireless last-mile connectivity. Physical and MAC layer of this technology refer to the IEEE 802.16e standard, which defines 5 different data delivery service classes that can be used in order to satisfy Quality of Service (QoS) requirements of different applications, such as VoIP, videoconference, FTP, Web, etc. In this paper we have made six scenarios. Here two types of MAC layer QoS are used and they are UGS and rtPS having application of Voice over IP (VoIP) and MPEG respectively. Also the traffic priority for UGS is high as compared to rtPS. In each scenario the number of fixed nodes (Fixed Subscriber Stations) and Mobile nodes (Mobile Subscriber Stations) are different. To cover more nodes or if nodes are outside the coverage area more than one BS are required. All the simulation results based on optimized networks and area we have considered between Bhusaval and Jalgam.
文摘单对线以太网是近年来新兴的以太网技术,随着汽车自动驾驶和工业物联网的高速发展,凭借上层应用扩展和底层布线上的绝对优势,正在大规模应用。单对线以太网物理层模拟前端技术是实现单对线以太网通信的关键基础技术。本文讲述了现有单对线以太网物理层模拟前端相关的标准,架构及相关模块设计技术,重点对发射器TX和接收器RX关键模块的现有实现技术及其优缺点进行了列举分析。发射器TX电流模结构易于实现高精度但功耗效率低,电压模结构精度略低但功耗效率更高;接收器RX的设计围绕模拟数字转换器(Analog-to-Digital Converter,ADC)展开,ADC决定着整个RX的性能、功耗、面积和复杂度,分段和重新装配(Segmentation And Reassembly,SAR)ADC是首选结构,应用上限不断提高。由此进一步明确了在高性能、低功耗、小面积的单对线以太网物理层模拟前端设计中的挑战。
文摘针对物理层抽象技术缺乏理论模型以及等效指数信噪比映射(EESM)物理层抽象算法依赖调整参数和通用性较差的缺点,依据信息论、信号检测和概率理论,提出了物理层抽象的概率模型,并据此推导得出基于平均互信息量的物理层抽象算法——块平均接收信息率(RBIR)算法。基于采用MIMO-OFDM技术和最小均方误差(MMSE)检测算法的WiMaxⅡ系统的仿真结果表明,对于ITU PedB 3kmph和ITU VA 30kmph信道模型、多种调制编码方式,该算法都能够获得与EESM算法相当的性能,并且不需要相关的调整参数,从而使得该算法更具一般性,能够较容易地扩展到不同的无线通信系统中,实现物理层抽象。该算法的有效性进一步验证了本文提出的物理层抽象概率模型。
