本期目录

2012年 19卷 2期 刊出日期：2012-04-30



Wireless

Optimal energy-efficiency capacity and sensing tradeoff for hybrid spectrum sharing in CRN

邱涛 许文俊 宋涛 贺志强 田宝玉

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60238-0

摘要 ( 2291 ) PDF (0 KB)( 229 )

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This paper investigates the tradeoff between energy-efficiency capacity and spectrum sensing under hybrid spectrum sharing model, where the spectrum sharing method is based on sensing results of secondary user (SU). The metric ‘bits per joule’, which captures the effect of energy overhead in spectrum sensing, is adopted to evaluate energy-efficiency capacity. We first formulize the tradeoff between energy-efficiency capacity and spectrum sensing as an optimization problem with mixture constraint of sensing time and detection threshold. Under some certain condition on the domain of detection threshold, i.e. in which we can’t improve energy-efficiency capacity through increasing the detection probability, the original optimization problem can be reduced to a new unconstrained one, which only relates to sensing time. Then the existence and uniqueness of optimal sensing time to achieve maximum energy-efficiency capacity are discussed and a low-complexity algorithm is proposed to obtain the optimal solution. Finally, numerical simulation is performed to verify the theoretical analysis results. The simulation results indicate that hybrid spectrum sharing is remarkably beneficial to energy-efficient transmission in cognitive radio networks (CRN). And the proposed algorithm can quickly converge to the optimal solution.

Particle filter based automatic frequency control scheme by combining the two-step structure

陈鹏 李巨虎 牛凯 吴伟陵

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60239-2

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In this paper a new automatic frequency control (AFC) scheme was proposed, which could be used for the receiver of low earth orbit (LEO) satellite communication system in continuous transmitting scenario. By employing the time varying characteristic of particle filter technique, the new scheme combined the preamble based estimating step and data based estimating step to provide initial probability density recursively. Theoretical analysis proved that the proposed AFC scheme could provide better performance than the two-step scheme. The same conclusion was achieved by computer simulations with the criteria of root-mean square (RMS) frequency estimating performance and bit error rate performance.

Achievable rate for three-node discrete memoryless relay channel with generalized feedbacks

郎非 王保云

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60240-9

摘要 ( 1791 ) PDF (0 KB)( 171 )

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This paper studies the achievable rate for three-node discrete memoryless relay channel. Specifically in this mode, we explore two generalized feedbacks simultaneously: the source node actively collects feedback signals from the channel; and at the same time, the destination node actively transmits feedback signals to the relay node. These two feedback signals, which are called generalized feedback overheard from the channel that is likely to be noisy, induce that all the three nodes are in full duplex mode. The basic coding strategies of Cover and El Gamal are applied to the relay-source feedback transmission by the source forwarding the compressions of the channel output sequences at the relay node to the destination, and are also applied to the destination-relay feedback transmission to improve the decoding ability at the relay. Based on Cover and El Gamal coding, a new coding scheme adopting rate splitting and four-block Markov superposition encoding is proposed and the corresponding achievable rate is achieved. The proposed scheme is able to exploit two feedbacks simultaneously which can effectively eliminate underlying transmission bottlenecks for the channels. The derived achievable rate result generalizes several previously known results by including them as special cases.

NLOS error mitigation with information fusion algorithm for UWB ranging systems

姜向远 张焕水 王伟

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60241-0

摘要 ( 2431 ) PDF (0 KB)( 179 )

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This article puts forward a scalar weighting information fusion (IF) smoother with modified biased Kalman filter (BKF) and maximum likelihood estimation (MLE) to mitigate the ranging errors in ultra wide band (UWB) systems. The information fusion algorithm uses both the time of arrival (TOA) and received signal strength (RSS) measurement data to improve the ranging accuracy. At first, the ranging protocol of IEEE 802.15.4a acts as a multi-sensor system with multi-scale sampling. Then the scalar-based IF smoother accurately estimates the range measurement in the line of sight (LOS) and non-line of sight (NLOS) condition of UWB sensor network，during which the effectiveness of the IF in mitigating errors is especially focused during the LOS/NLOS transitions. Simulation results show that the proposed hybrid TOA-RSS fusion approach indicates a performance improvement compared with the usual TOA-only and other IF method, and the estimated ranging metrics can be used for achieving higher accuracy in location estimation and target tracking.

Min-max load balancing scheme for mixed multicast and unicast services in LTE networks

汪敏 冯春燕 张天魁

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60242-2

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To avoid the traffic congestion in long term evolution (LTE) networks, a min-max load balancing (LB) scheme is proposed to minimize the demanded radio resources of the maximum loaded cell. For the mixed multicast and unicast services, multicast services are transmitted by single frequency network (SFN) mode and unicast services are delivered with point-to-point (PTP) mode. The min-max LB takes into account point-to-multipoint (PTM) mode for multicast services and selects the proper transmission mode between SFN and PTM for each multicast service to minimize the demanded radio resources of the maximum loaded cell. Based on the solution of this minimization problem, if the maximum loaded cell does not overload, the min-max LB will change PTM mode into SFN mode for multicast services to achieve high quality of service (QoS). Simulation results show that the proposed min-max LB scheme requires less radio resources from the maximum loaded cell than SFN mode for all multicast services.

Inter-femtocell interference coordination in 3D in-building scenario

胡丹 李宏佳 许晓东 陶小峰

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60243-4

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With rapid development of femtocell, dense deployment of femtocells in buildings will become an important study scenario. In this scenario, there exists severe inter-femtocell interference in the same building, which is revealed by our simulations in the 3-dimention (3D) scenario. If this type of interference is not well controlled, services to indoor users are bound to be deteriorated, especially for the femtocell edge users. Motivated by this problem, femto users’ received interference model is constructed based on the scenario of 3D femtocell deployment. Then, a graph theory based in-building inter-femtocell coordination scheme is proposed, which includes three phases: establishment of femtocell interference graph, femtocell clustering and frequency resources allocation based on the proposed cluster influence circle. Finally, the simulation results confirm that the proposed scheme improves the femtocell average throughput by 22.4% and 26.2% in comparison with frequency universal reuse scheme and frequency hopping scheme respectively, and ensures the channel demodulation reliability of cell edge femto users.

New predistorter using triangular memory polynomial for power amplifier of OFDM-based wireless broadband communication system

于翠屏 刘元安 都天骄 Li Shu-lan

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60244-6

摘要 ( 2240 ) PDF (0 KB)( 180 )

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A triangular memory polynomial (TMP) predistorter is presented in this paper to linearize a power amplifier’s nonlinear with memory effects. Compared with the traditional memory polynomial (MP) predistorter, the coefficients of TMP predistorter is reduced more than 75%, which can effectively decrease the implementation complexity. The coefficients of predistorter are directly extracted from an offline system identification process by an open-loop structure in our approach. Several signals with data rate 5 MHz, 10 MHz, 15 MHz and 20 MHz are used to verify the performance of the proposed predistorter. Experimental results show that the proposed TMP predistorter and the traditional MP predistorter almost have the same performance.

Networks

Optimized in-band control channel with channel selection scheduling and network coding in distributed cognitive radio networks

刘阳 冯志勇 张平

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60245-8

摘要 ( 1968 ) PDF (0 KB)( 199 )

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This article proposes an optimized in-band control channel scheme with channel selection scheduling algorithm and network coding based transmission paradigm in the distributed cognitive radio network (CRN). As well known, control channel plays an important role for establishment of wireless transmission. In order to improve spectrum efficiency in CRN, control channel is preferred to be deployed without dedicated spectrum allocation, i.e. the in-band way. In this study, the time slot division and dynamic channel selection scheduling algorithm is proposed to realize the in-band control channel with improved spectrum efficiency in the distributed CRN. Furthermore, to adapt to dynamic behavior of the primary users, network coding technology is employed to optimize the overhead of control information transmission so that the control information can be efficiently and reliably transmitted. The performance of the proposed in-band control channel scheme is verified by the extensive simulation results.

Modeling and application of moderate prefetching strategy based on video slicing for P2P VoD systems

邓光青 危婷 陈常嘉 朱巍 王斌 吴登荣

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60246-X

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In peer-to-peer (P2P) video-on-demand (VoD) streaming systems, each peer contributes a fixed amount of hard disk storage (usually 2 GB) to store viewed videos and then uploads them to other requesting peers. However, the daily hits (namely popularity) of different segments of a video is highly diverse, which means that taking the whole video as the basic storage unit may lead to redundancy of unpopular segment replicas and scarcity of popular segment replicas in the P2P storage network. To address this issue, we propose a video slicing mechanism (VSM) in which the whole video is sliced into small blocks (20 MB, for instance). Under VSM, peers can moderately remove unpopular blocks from and accordingly add popular ones into their contributed hard disk storage, which increases the usage of peers’ contributed resource (storage and bandwidth). To reasonably assign bandwidth among peers with different download capacity, we propose a moderate prefetching strategy (MPS) based on VSM. Under MPS, when the amount of prefetched content reaches the predefined threshold, peers immediately stop prefetching video content and then release occupied bandwidth for others. A stochastic model is established to analyze the performance of the MPS and it is found that perfect playback continuity can be got under MPS. Then the MPS is applied to PPLive VoD system (one of the largest P2P VoD systems in China) and measurement results demonstrate that low server load and perfect user satisfaction can be achieved. Also, the server bandwidth contribution of PPLive VoD system under MPS (namely 5%) is much lower than that of UUSee VoD system (namely 30%).

Timely traffic identification on P2P streaming media

杨洁 袁仑 贺阳 CHEN Lu-ying

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60247-1

摘要 ( 1942 ) PDF (0 KB)( 151 )

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Since the year of 2006, peer-to-peer (P2P) streaming media service has been developing rapidly, the user scale and income scale achieve synchronous growth. However, while people enjoying the benefits of the distributed resources, a great deal of network bandwidth is consumed at the same time. Research on P2P streaming traffic characteristics and identification is essential to Internet service providers (ISPs) in terms of network planning and resource allocation. In this paper, we introduce the current common P2P traffic detection technology, and analyze the payload length distribution and payload length pattern in one flow of four popular P2P streaming media applications. Combining with the deep flow inspection and machine learning algorithm, a nearly real-time identification approach for P2P streaming media is proposed. The experiments proved that this approach can achieve a high accuracy with low false positives.

Joint relay station deployment and frequency reuse scheme for two-hop cellular networks

陈浩凯 尹慧 梁剑 李中年 刘守印

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60248-3

摘要 ( 1822 ) PDF (0 KB)( 194 )

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To fully exploit the performance benefits of relay station (RS), in the two-hop cellular networks covering hotspots, when the number of RSs is predetermined, both RS deployment and frequency reuse scheme are jointly optimized for the purpose of maximizing the system capacity based on the constraints of system demand of capacity and the maximum number of outage demand nodes (MNDN). Further, considering the overhead of increasing RSs, it is desired to use minimum number of RSs. The joint RS deployment and frequency reuse scheme (JRDFR) problem is formulated into a mixed integer nonlinear programming, which is non-deterministic polynomial-time hard in general. A heuristic approach based on genetic algorithm is proposed to tackle the JRDFR problem. The computational experiment of the heuristic approach is achieved and optimized RS deployment and frequency reuse scheme is obtained. Finally, we discuss the impacts of MNDN and the number of RSs on the system performance.

AAA authentication for network mobility

张洁 刘元安 马晓雷 贾锦涛

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60249-5

摘要 ( 2087 ) PDF (0 KB)( 162 )

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Network mobility (NEMO) is a protocol proposed for the mobility management of a whole network. It offers seamless Internet connectivity to the mobile end users. However, the NEMO protocol has not been widely used in Internet, because it has not considered the secure problem about authentication and authorization. The proposed framework designed an access control scheme especially used for the NEMO network environment. It is based on the authentication, authorization, and accounting (AAA) system. It can make use of the mobile router to authenticate for all the mobile nodes at the same time, and uses the mobile network node (MNN)-list synchronization mechanism to control the secure access of the MNN. By using the foreign AAA server cache mechanism, this scheme can decrease the authentication time delay and improve the efficiency of the network. The advantages are proved by the comparison with other recent related studies via the OPNET simulations.

Integration of IoT and DRAGON-lab in cloud environment

范通让 高峰 张宣 王旭

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60250-1

摘要 ( 2322 ) PDF (0 KB)( 192 )

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Distributed research & academic gigabits open network lab (DRAGON-lab) is the only test-bed for research purpose related to next generation internet (NGI) which based on the confederation network using three layers cloud structure. As an essential part of NGI, the research related to the Internet of things (IoT) devices should be applied on the DRAGON-lab platform. This paper proposes an approach to converging the IoT devices to confederation network by integrating each layer of cloud structure between DRAGON-lab and IoT. This research activity extends the use of DRAGON-lab, makes the IoT and wireless sensor network (WSN) devices working well in the confederation network. It was also a foundational research for three layers cloud structure, which could be reused for other related research. Finally, it finishes the preparation work for IoT internet protocol version 6 (IPv6) devices research in DRAGON-lab, which is essential for the NGI.

Others

Decomposition and compression for ECG and EEG signals with sequence index coding method based on matching pursuit

张洪欣 CHEN Can-feng WU Yan-ling LI Pei-hua

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60251-3

摘要 ( 2246 ) PDF (0 KB)( 164 )

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An efficient compression method is proposed by encoding the sequence index of atoms based on matching pursuit (MP) algorithm with over-complete Gabor dictionary, which has the merit to adjust the compression ratio (CR) according to the practical request with low distortion. It is also combined with genetic algorithm (GA) to reduce the computation complexity. Then, the validity of this method is verified by applying it in the compression of electrocardiography (ECG) and Electroencephalography (EEG) signals. The simulation results show that the CR can be achieved at 18:1 with only 1.06% and 2.15% reconstruction errors on ECG and EEG signals respectively. It has higher CR and less reconstruction errors compared to that of the traditional methods, and noise suppression effect is also presented.

Quasi-cyclic LDPC codes with high-rate and low error floor based on Euclidean geometries

刘原华 张美玲 范九伦

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60252-5

摘要 ( 1959 ) PDF (0 KB)( 175 )

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An improved Euclidean geometry approach to design quasi-cyclic (QC) Low-density parity-check (LDPC) codes with high-rate and low error floor is presented. The constructed QC-LDPC codes with high-rate have lower error floor than the original codes. The distribution of the minimum weight codeword is analyzed, and a sufficient existence condition of the minimum weight codeword is found. Simulations show that a lot of QC-LDPC codes with lower error floor can be designed by reducing the number of the minimum weight codewords satisfying this sufficient condition.

Improved particle filter based on fine resampling algorithm

曹蓓 马彩文 刘镇弢

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60253-7

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In order to solve particle degeneracy phenomenon and simultaneously avoid sample impoverishment, this paper proposed an improved particle filter based on fine resampling algorithm for general case, called as particle filter with fine resampling (PF-FR). By introducing distance-comparing process and generating new particle based on optimized combination scheme, PF-FR filter performs better than generic sampling importance resampling particle filter (PF-SIR) both in terms of effectiveness and diversity of the particle system, hence, evidently improving estimation accuracy of the state in the nonlinear/non-Gaussian models. Simulations indicate that the proposed PF-FR algorithm can maintain the diversity of particles and thus achieve the same estimation accuracy with less number of particles. Consequently, PF-FR filter is a competitive choice in the applications of nonlinear state estimation.

Simultaneous image classification and annotation based on probabilistic model

李晓旭 孙超博 鲁鹏 王小捷 ZHONG Yi-xin

中国邮电高校学报(英文), 2012, 19 (2). doi： : 10.1016/S1005-8885(11)60254-9

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The paper proposes a novel probabilistic generative model for simultaneous image classification and annotation. The model considers the fact that the category information can provide valuable information for image annotation. Once the category of an image is ascertained, the scope of annotation words can be narrowed, and the probability of generating irrelevant annotation words can be reduced. To this end, the idea that annotates images according to class is introduced in the model. Using variational methods, the approximate inference and parameters estimation algorithms of the model are derived, and efficient approximations for classifying and annotating new images are also given. The power of our model is demonstrated on two real world datasets: a 1 600-images LabelMe dataset and a 1 791-images UIUC-Sport dataset. The experiment results show that the classification performance is on par with several state-of-the-art classification models, while the annotation performance is better than that of several state-of-the-art annotation models.

PCE-based routing and spectrum assignment in OFDM-based bandwidth-variable optical networks

赵永利 张杰 王晶晶 GU Wan-yi

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60255-0

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Bandwidth-variable optical networks can not only provide bandwidth-flexible lightpaths, but also complete high capacity all-optical switching, and improve the spectrum efficiency. However, for the spectrum assignment in orthogonal frequency-division multiplexing (OFDM)-based bandwidth-variable optical networks, a lot of sub-carrier resources will be overlapped during the process of reservation with distributed signaling, whether for the first fit (FF) algorithm or for the random fit (RF) algorithm. In order to solve the issue of resource reservation collision, we propose two path computation element (PCE)-based spectrum assignment algorithms and two corresponding optimization algorithms. But, even for PCE-based spectrum assignment, a lot of fragments of sub-carrier resources will be generated during the process of resource reservation, and service LSP establishment and teardown, which will deteriorate the performance of the entire network seriously. This paper proposes a PCE-based defragmentation algorithm for sub-carriers spectrum resource in OFDM-based bandwidth-variable optical networks, the simulation results of which show that this algorithm can reduce sub-carriers fragments considerably and improve the continuity of spectrum resource.

Novel radiation pattern reconfigurable antenna with six beam choices

蔡晓涛 王安国 马宁 冷文

中国邮电高校学报(英文), 2012, 19 (2). doi： 10.1016/S1005-8885(11)60256-2

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This article presents a novel radiation pattern reconfigurable antenna with six beam choices, which works in 5.2 GHz wireless local area network (WLAN) frequency band. The designed antenna has good impedance matching at the resonant frequency. The beam can be reconfigured to six different directions, and each main lobe of six azimuth patterns has a half power beam width (HPBW) of about . The antenna can cover all directions in the azimuth plane (XY-plane) by controlling the states (ON or OFF) of six switches. Simulation and measurement have been carried out to validate the design and experimental results demonstrate that the proposed antenna has the capacity to provide the pattern reconfigurability.