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  • REVIEW PAPER
    Trends of Communication Processors
    LIU Dake, CAI Zhaoyun*, WANG Wei
    2016, 13(1): 1-16.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Processors have been playing important roles in both communication infrastructure systems and terminals. In this paper, both application specific and general purpose processors for communications are discussed including the roles, the history, the current situations, and the trends. One trend is that ASIPs (Application Specific Instruction-set Processors) are taking over ASICs (Application Specific Integrated Circuits) because of the increasing needs both on performance and compatibility of multi-modes. The trend opened opportunities for researchers crossing the boundary between communications and computer architecture. Another trend is the serverlization, i.e., more infrastructure equipments are replaced by servers. The trend opened opportunities for researchers working towards high performance computing for communication, such as research on communication algorithm kernels and real time programming methods on servers.
    • CHANNEL CHARACTERIZATION AND MODELING
  • CHANNEL CHARACTERIZATION AND MODELING
    A Modified Doppler Frequency Trajectory Undergoing Varying Velocities in HSR Communications
    LIU Liu, TAO Cheng, SUN Rongchen, CHEN Houjin
    2016, 13(1): 17-21.
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    The varying trajectory of Doppler frequency under changing speed motion conditionsare investigated in HighSpeed Railway (HSR) scenarios. Based on the geometrical physical parameters, instantaneous Doppler trajectories and expression forms of the change rate arededuced, including acceleration and deceleration cases.These modified models provide more accurate and realisticapproximations in modeling rapidly fading channels.
  • CHANNEL CHARACTERIZATION AND MODELING
    On Multi-Frequency Channel Interference Alignment of 3 Channels and 4 Users
    DU Guanglong, ZOU Weixia, ZHOU Zheng
    2016, 13(1): 22-32.
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    This paper explores the multi-frequency independent channel interference alignment (MFC-IA) system of 3 channels and 4 users, and single data stream transmit, i.e. (3×3,1)4 system. We derive the analytic solution for (3×3,1)4 MFC-IA system. Based on the analytic solution, an optimization problem is proposed aim at the optimal IA solution. Then based on such a math model, we propose a simulated annealing (SA) algorithm to search optimal IA solution. The simulation results show that the simulated annealing IA algorithm has a better sum rate performance than iterative maximize signal to interference plus noise ratio (Max-SINR) algorithm. This result can be extended to single data stream multi-antenna IA system with 3 antennas and 4 users.
    • COMMUNICATIONS SYSTEM DESIGN
  • COMMUNICATIONS SYSTEM DESIGN
    A Low Power Non-Volatile LR-WPAN Baseband Processor with Wake-Up Identification Receiver
    YU Shuangming, FENG Peng, WU Nanjian
    2016, 13(1): 33-46.
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    The paper proposes a low power non-volatile baseband processor with wake-up identification (WUI) receiver for LR-WPAN transceiver. It consists of WUI receiver, main receiver, transmitter, non-volatile memory (NVM) and power management module. The main receiver adopts a unified simplified synchronization method and channel codec with proactive Reed-Solomon Bypass technique, which increases the robustness and energy efficiency of receiver. The WUI receiver specifies the communication node and wakes up the transceiver to reduce average power consumption of the transceiver. The embedded NVM can backup/restore the states information of processor that avoids the loss of the state information caused by power failure and reduces the unnecessary power of repetitive computation when the processor is waked up from power down mode. The baseband processor is designed and verified on a FPGA board. The simulated power consumption of processor is 5.1μW for transmitting and 28.2μW for receiving. The WUI receiver technique reduces the average power consumption of transceiver remarkably. If the transceiver operates 30 seconds in every 15 minutes, the average power consumption of the transceiver can be reduced by two orders of magnitude. The NVM avoids the loss of the state information caused by power failure and energy waste caused by repetitive computation.
  • COMMUNICATIONS SYSTEM DESIGN
    Sensing Time Optimization in Energy-Harvesting Cognitive Radio with Interference Rate Control
    DENG Zhian, LIU Xin, JIA Min, LU Weidang
    2016, 13(1): 47-56.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    In this paper, an energy-harvesting cognitive radio (CR) is considered, which allows the transmitter of the secondary user (SU) to harvest the primary signal energy from the transmitter of the primary user (PU) when the presence of the PU is detected. Then the harvested energy is converted into the electrical power to supply the transmission of the SU at the detected absence of the PU. By adopting the periodic spectrum sensing, the average total transmission rate of the SU is maximized through optimizing the sensing time, subject to the constraints of the probabilities of false alarm and detection, the harvested energy and the interference rate control. The simulation results show that there deed exists an optimal sensing time that maximizes the transmission rate, and the maximum transmission rate of the energy-harvesting CR can better approach to that of the traditional CR with the increasing of the detection probability.
  • COMMUNICATIONS SYSTEM DESIGN
    Coordinated Multi-User Spectrum Sharing in Distributed Antenna-Based Cognitive Radio Systems
    ZHAO Juntao, FENG Wei, ZHAO Ming, WANG Jing
    2016, 13(1): 57-67.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Spectrum sharing for efficient reuse of licensed spectrum is an important concept for cognitive radio technologies. In a spectrum-sharing system (SSS), deploying the antennas in a distributed manner can offer a new spatial dimension for the efficient reuse of licensed frequency bands. To improve the whole performance of multiple secondary users (SUs), this paper addresses the problem of coordinated multi-SU spectrum sharing in a distributed antenna-based SSS. By adopting the Hungarian method, the primal decomposition method and pricing policy, we propose a coordinated multi-user transmission scheme, so as to maximize the sum-rate of SUs. Simulation results show that the proposed method can significantly enhance the system performance, and the computational complexity is low.
    • NETWORK TECHNOLOGY AND APPLICATION
  • NETWORK TECHNOLOGY AND APPLICATION
    The New Architecture with Time-Spatial Consistency for 5G Networks
    SUN Zhennian, XU Xu, CHAI Xiaomeng, ZHANG Tianyu, TIAN Lin, ZHANG Zhongshan
    2016, 13(1): 68-79.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    While operators have started deploying fourth generation (4G) wireless communication systems, which could provide up to 1Gbps downlink peak data rate, the improved system capacity is still insufficient to meet the drastically increasing demand of mobile users over the next decade. The main causes of the above-mentioned phenomenon include the following two aspects: 1) the growth rate of the network capacity is far below that of user’s demand, and 2) the relatively deterministic wireless access network (WAN) architecture in the existing systems cannot accommodate the prominent increase of mobile traffic with space-time domain dynamics. In order to address the above-mentioned challenges, we investigate the time-spatial consistency architecture for the future WAN, whilst emphasizing the critical roles of some spectral-efficient techniques such as Massive multiple-input multiple-output (MIMO), full-duplex (FD) operation and heterogeneous networks (HetNets). Furthermore, the energy efficiency (EE) of the HetNets under the proposed architecture is also evaluated, showing that the proposed user-selected uplink power control algorithm outperforms the traditional stochastic-scheduling strategy in terms of both capacity and EE in a two-tier HetNet. The other critical issues, including the tidal effect, the temporal failure owing to the instantaneously increased traffic, and the network wide load-balancing problem, etc., are also anticipated to be addressed in the proposed architecture. (Abstract)
  • NETWORK TECHNOLOGY AND APPLICATION
    Distributed Chunk-Based Optimization for Multi-Carrier Ultra-Dense Networks
    GUO Shaozhen, XING Chengwen, FEI Zesong, ZHOU Gui, YAN Xinge
    2016, 13(1): 80-90.
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    In this paper, a distributed chunk-based optimization algorithm is proposed for the resource allocation in broadband ultra-dense small cell networks. Based on the proposed algorithm, the power and subcarrier allocation problems are jointly optimized. In order to make the resource allocation suitable for large scale networks, the optimization problem is decomposed first based on an effective decomposition algorithm named optimal condition decomposition (OCD) algorithm. Furthermore, aiming at reducing implementation complexity, the subcarriers are divided into chunks and are allocated chunk by chunk. The simulation results show that the proposed algorithm achieves more superior performance than uniform power allocation scheme and Lagrange relaxation method, and then the proposed algorithm can strike a balance between the complexity and performance of the multi-carrier Ultra-Dense Networks.
    • SECURITY SCHEMES AND SOLUTIONS
  • SECURITY SCHEMES AND SOLUTIONS
    A Reconfigurable Block Cryptographic Processor Based on VLIW Architecture
    LI Wei, ZENG Xiaoyang, NAN Longmei, CHEN Tao, DAI Zibin
    2016, 13(1): 91-99.
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    An Efficient and flexible implementation of block ciphers is critical to achieve information security processing. Existing implementation methods such as GPP, FPGA and cryptographic application-specific ASIC provide the broad range of support. However, these methods could not achieve a good tradeoff between high-speed processing and flexibility. In this paper, we present a reconfigurable VLIW processor architecture targeted at block cipher processing, analyze basic operations and storage characteristics, and propose the multi-cluster register-file structure for block ciphers. As for the same operation element of block ciphers, we adopt reconfigurable technology for multiple cryptographic processing units and interconnection scheme. The proposed processor not only flexibly accomplishes the combination of multiple basic cryptographic operations, but also realizes dynamic configuration for cryptographic processing units. It has been implemented with 0.18µmCMOS technology, the test results show that the frequency can reach 350MHz, and power consumption is 420mw. Ten kinds of block and hash ciphers were realized in the processor. The encryption throughput of AES, DES, IDEA, and SHA-1 algorithm is 1554Mbps, 448Mbps, 785Mbps, and 424Mbps respectively, the test result shows that our processor’s encryption performance is significantly higher than other designs.
  • SECURITY SCHEMES AND SOLUTIONS
    Design and Implementation of Verification Code Identification Based on Anisotropic Heat Kernel
    LIU Lizhao, LIU Jian, DAI Yaomei, XU Huarong, YIN Huayi, ZHU Shunzhi
    2016, 13(1): 100-112.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Many websites use verification codes to prevent users from using the machine automatically to register, login, malicious vote or irrigate but it brought great burden to the enterprises involved in internet marketing as entering the verification code manually. Improving the verification code security system needs the identification method as the corresponding testing system. We propose an anisotropic heat kernel equation group which can generate a heat source scale space during the kernel evolution based on infinite heat source axiom, design a multi-step anisotropic verification code identification algorithm which includes core procedure ofbuilding anisotropic heat kernel, settingwave energy information parameters, combing outverification codecharacters and corresponding peripheral procedure of gray scaling, binarizing, denoising, normalizing, segmenting and identifying, give out the detail criterion and parameter set. Actual test show the anisotropic heat kernel identification algorithm can be used on many kinds of verification code including text characters, mathematical, chinese, voice, 3D, programming, video, advertising, it has a higher rate of 25% and 50% than neural network and context matching algorithm separately for Yahoo site, 49% and 60% for Captcha site, 20% and 52% for Baidu site, 60% and 65% for 3DTakers site, 40% and 51% for MDP site.
  • SECURITY SCHEMES AND SOLUTIONS
    A Concurrent Security Monitoring Method for Virtualization Environments
    TIAN Donghai, JIA Xiaoqi, CHEN Junhua, HU Changzhen
    2016, 13(1): 113-123.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Recently, virtualization technologies have been widely used in industry. In order to monitor the security of target systems in virtualization environments, conventional methods usually put the security monitoring mechanism into the normal functionality of the target systems. However, these methods are either prone to be tempered by attackers or introduce considerable performance overhead for target systems. To address these problems, in this paper, we present a concurrent security monitoring method which decouples traditional serial mechanisms, including security event collector and analyzer, into two concurrent components. On one hand, we utilize the SIM framework to deploy the event collector into the target virtual machine. On the other hand, we combine the virtualization technology and multi-core technology to put the event analyzer into a trusted execution environment. To address the synchronization problem between these two concurrent components, we make use of Lamport’s ring buffer algorithm. Based on the Xen hypervisor, we have implemented a prototype system named COMO. The experimental results show that COMO can monitor the security of the target virtual machine concurrently within a little performance overhead.
  • SECURITY SCHEMES AND SOLUTIONS
    Optimized Algorithms for Flexible Length-Based Authenticated Skip List
    XU Jian, LI Mingjie, LI Fuxiang, YANG Qingsong, ZHOU Fucai
    2016, 13(1): 124-138.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    With the growing trend toward using cloud storage, the problem of efficiently checking and proving data integrity needs more consideration. Many cryptography and security schemes, such as PDP (Provable Data Possession) and POR (Proofs of Retrievability) were proposed for this problem. Although many efficient schemes for static data have been constructed, only a few dynamic schemes exist, such as DPDP (Dynamic Provable Data Possession). But the DPDP scheme falls short when updates are not proportional to a fixed block size. The FlexList-based Dynamic Provable Data Possession (FlexDPDP) was an optimized scheme for DPDP. However, the update operations (insertion, remove, modification) in Flex DPDP scheme only apply to single node at a time, while multiple consecutive nodes operation is more common in practice.To solve this problem, we propose optimized algorithms for multiple consecutive nodes, which including MultiNodes Insert and Verification, MultiNodes Remove and Verification, MultiNodes Modify and Verification. The cost of our optimized algorithms is also analyzed. For m consecutive nodes, an insertion takes O(m)+O(logN)+O(logm), where N is the number of leaf nodes of FlexList, a remove takes O(logN), and a modification is the same as the original algorithm. Finally, we compare the optimized algorithms with original FlexList through experiences, and the results show that our scheme has the higher efficiency of time and space.
  • SECURITY SCHEMES AND SOLUTIONS
    Improving Image Copy-Move Forgery Detection with Particle Swarm Optimization Techniques
    SHI Wenchang, ZHAO Fei, QIN Bo, LIANG Bin
    2016, 13(1): 139-149.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    Copy-Move Forgery (CMF) is one of the simple and effective operations to create forged digital images. Recently, techniques based on Scale Invariant Features Transform (SIFT) are widely used to detect CMF. Various approaches under the SIFT-based framework are the most acceptable ways to CMF detection due to their robust performance. However, for some CMF images, these approaches cannot produce satisfactory detection results. For instance, the number of the matched keypoints may be too less to prove an image to be a CMF image or to generate an accurate result. Sometimes these approaches may even produce error results. According to our observations, one of the reasons is that detection results produced by the SIFT-based framework depend highly on parameters whose values are often determined with experiences. These values are only applicable to a few images, which limits their application. To solve the problem, a novel approach named as CMF Detection with Particle Swarm Optimization (CMFD-PSO) is proposed in this paper. CMFD-PSO integrates the Particle Swarm Optimization (PSO) algorithm into the SIFT-based framework. It utilizes the PSO algorithm to generate customized parameter values for images, which are used for CMF detection under the SIFT-based framework. Experimental results show that CMFD-PSO has good performance.
  • SECURITY SCHEMES AND SOLUTIONS
    Security Analysis and Enhanced Design of a Dynamic Block Cipher
    ZHAO Guosheng, WANG Jian
    2016, 13(1): 150-160.
    Abstract ( ) Download PDF ( )   Knowledge map   Save
    There are a lot of security issues in block cipher algorithm. Security analysis and enhanced design of a dynamic block cipher was proposed. Firstly, the safety of ciphertext was enhanced based on confusion substitution of S-box, thus disordering the internal structure of data blocks by four steps of matrix transformation. Then, the diffusivity of ciphertext was obtained by cyclic displacement of bytes using column ambiguity function. The dynamic key was finally generated by using LFSR, which improved the stochastic characters of secret key in each of round of iteration. The safety performance of proposed algorithm was analyzed by simulation test. The results showed the proposed algorithm has a little effect on the speed of encryption and decryption while enhancing the security. Meanwhile, the proposed algorithm has highly scalability, the dimension of S-box and the number of register can be dynamically extended according to the security requirement.
  • SECURITY SCHEMES AND SOLUTIONS
    DPTSV: A Dynamic Priority Task Scheduling Strategy for TSS Deadlock Based on Value Evaluation
    ZHAO Bo, XIANG Shuang, AN Yang, TAO Wei
    2016, 13(1): 161-175.
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    This paper analyzes the threat of TCG Software Stack (TSS)/TCM Service Module (TSM) deadlock in multi-user environment such as cloud and discusses its causes and mechanism. In addition, this paper puts forward a dynamic priority task scheduling strategy based on value evaluation to handle this threat. The strategy is based on the implementation features of trusted hardware and establishes a multi-level ready queue. In this strategy, an algorithm for real-time value computing is also designed, and it can adjust the production curves of the real time value by setting parameters in different environment, thus enhancing its adaptability, which is followed by scheduling and algorithm description. This paper also implements the algorithm and carries out its performance optimization. Due to the experiment result from Intel NUC, it is shown that TSS based on advanced DPTSV is able to solve the problem of deadlock with no negative influence on performance and security in multi-user environment.
    • STRATEGIES AND SCHEMES
  • STRATEGIES AND SCHEMES
    An Anti-Eavesdrop Transmission Scheduling Scheme Based on Maximizing Secrecy Outage Probability in Ad Hoc Networks
    WANG Yajun, LIAO Tongqing, WANG Chuanan
    2016, 13(1): 176-184.
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    In this paper, we consider a wireless ad hoc network consisting of multiple source nodes transmitting to their respective destinations, where an eavesdropper attempts to intercept their transmissions. We propose an optimal transmission scheduling scheme to defend against the eavesdropper, where a source node having the highest secrecy rate is scheduled to access the wireless medium for transmitting to its destination in an opportunistic manner. To be specific, the secrecy rate between a pair of the source and destination in the presence of an eavesdropper varies temporally due to the wireless fading effect. The proposed optimal transmission scheduling scheme opportunistically selects a source node with the highest secrecy rate to transmit its data for the sake of maximizing the security of the ad hoc network against eavesdropping attacks. For comparison purposes, we also consider the conventional round-robin scheduling as a benchmark, where multiple source nodes take turns in accessing their shared wireless medium for transmitting to their respective destinations. We derive closed-form secrecy outage probability expressions of both the round-robin scheduling and the proposed optimal scheduling schemes over Rayleigh fading environments. Numerical results show that the proposed transmission scheduling scheme outperforms the conventional round-robin method in terms of its secrecy outage probability. Additionally, upon increasing the number of source-destination pairs, the secrecy outage probability of the round-robin scheme keeps unchanged, whereas the secrecy outage performance of the proposed transmission scheduling significantly improves, showing the security benefits of exploiting transmission scheduling for protecting wireless ad hoc networks against eavesdropping.