Province Key Laboratory of Software in Computing and Communication

Hefei, China

Province Key Laboratory of Software in Computing and Communication

Hefei, China
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Li P.,Anhui University of Science and Technology | Li P.,State Key Laboratory of Networking and Switching Technology | Li P.,NEC Laboratories America Inc. | Li P.,Province Key Laboratory of Software in Computing and Communication | And 5 more authors.
IEEE International Conference on Communications | Year: 2010

Scalable video coding (SVC) and Adaptive Modulation and Coding (AMC) are two key techniques for video multicast in broadband wireless networks. They can improve the system performance by enhancing the wireless resource allocation schemes and assigning appropriate modulation and coding schemes (MCS) to different layers of scalable video sequences. We formulate the problem as maximizing the total system utility subject to the total resource constraint, where the utility of each user is a generic non-negative, non-decreasing function of received rate. We then propose a fast intra-session MCS assignment algorithm based on dynamic programming. This algorithm can be integrated with an existing inter-session resource allocation algorithm and applied to multi-session scenarios. Simulation results show that our algorithm achieves significant improvement on the video quality over a naive algorithm and an adapted greedy algorithm, and greatly reduces the running time in both single-session and multi-session scenarios compared to a former optimal algorithm. ©2010 IEEE.


Jin J.,Anhui University of Science and Technology | Jin J.,State Key Laboratory of Networking and Switching Technology of | Jin J.,Province Key Laboratory of Software in Computing and Communication | Ji Y.,Japan National Institute of Information and Communications Technology | And 6 more authors.
IEICE Transactions on Communications | Year: 2010

With the increasing popularity of multicast and real-time streaming service applications, efficient channel assignment algorithms that handle both multicast and unicast traffic in wireless mesh networks are needed. One of the most effective approaches to enhance the capacity of wireless networks is to use systems with multiple channels and multiple radio interfaces. However, most of the past works focus on vertex coloring of a general contention graph, which is NP-Complete, and use the greedy algorithm to achieve a suboptimal result. In this paper, we combine unicast and multicast with a transmission set, and propose a framework named Chordal Graph Based Channel Assignment (CGCA) that performs channel assignment for multicast and unicast traffic in multi-channel multiradio wireless mesh networks. The proposed framework based on chordal graph coloring minimizes the interference of the network and prevents unicast traffic from starvation. Simulation results show that our framework provides high throughput and low end-to-end delay for both multicast and unicast traffic. Furthermore, our framework significantly outperforms other well-known schemes that have a similar objective in various scenarios. Copyright © 2010.


Li P.,University of Science and Technology of China | Li P.,NEC Laboratories America Inc. | Li P.,State Key Laboratory of Networking and Switching Technology | Li P.,Province Key Laboratory of Software in Computing and Communication | And 5 more authors.
Proceedings - International Conference on Network Protocols, ICNP | Year: 2010

Scalable video coding (SVC), together with adaptive modulation and coding (AMC), can improve wireless multicast streaming video by jointly performing radio resource allocation and modulation and coding scheme (MCS) selection. However, the existing schemes in the literature allocate radio resources for different video layers separately, which leads to a waste of radio resources. In this work, we introduce the notion of joint layer resource allocation which allows to jointly allocate resources to multiple video layers that are assigned the same MCS. We formulate this problem and prove it to be NP-hard. Then we develop a pseudo-polynomial algorithm that finds the optimal total system utility. Our algorithm assumes a very generic utility function and flexible video layer rates. To reduce the complexity of the algorithm, we also propose Fully Polynomial Time Approximation Schemes (FPTAS) for the same problem. Simulation results show that our optimal algorithm offers significant improvement on system utility over a previous optimal algorithm and a greedy algorithm both of which do not support joint layer resource allocation. The proposed approximation algorithm provides controllable tradeoff between performance and computational complexity and, with appropriately chosen parameters, it outperforms the greedy algorithm with 40% less running time. © 2010 IEEE.


Zhu J.,Hefei University of Technology | Zhu J.,State Key Laboratory of Networking and Switching Technology | Zhu J.,Province Key Laboratory of Software in Computing and Communication | Zhou H.,Hefei University of Technology | And 5 more authors.
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | Year: 2010

There are some loopholes in 802.1X protocol such as replay attacks, DoS (Denial of Service) attacks and so on. The paper presents an state transition process for certification of 802.1X, and designs an attack state transfer mechanism for functional attacks. The architecture of 802.11 frames, EAPOL frames and EAP frames are analyzed. The replay frames are deleted and keywords are abstracted and saved from the list of remaining frames one by one. Then the EAP frames which are required for detection are saved in the cache. The security detection method of 802.1X is designed based on the state transition mechanism. Experimental results show that functional attacks of 802.1X such as replay/DoS attacks can be detected accurately in real network environments, and the detection is effective and consistent.


Liu Z.,Hefei University of Technology | Liu Z.,State Key Laboratory of Networking and Switching Technology | Liu Z.,Province Key Laboratory of Software in Computing and Communication | Zhou H.,Hefei University of Technology | And 5 more authors.
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | Year: 2010

An adaptive security manage framework (ASMF) for WLAN (wireless local area network) is presented to focus on security problems of WLAN, based on which an adaptive security management system (ASMS) is built. The ASMF bases on the theory of protocol analyse and the theory of protocol testing. The active analysis method is applied to interact on the protocol by constructing the test case while the passive analysis method is applied to monitor the network data flow and the performance of WLAN. Hence, the ASMF can analyse the security of WLAN and manage the WLAN from integer. Compared with the existing security systems, the ASMF not only detects the attack passively, but also probes unknown threats. In addition the ASMF can adjust the defensive strategy according the configure of the WLAN. The good expansibility of ASMF allows users to extend new attacking testing, new attack detecting and customizing management strategy easily.


Huang Z.,Anhui University of Science and Technology | Huang Z.,State Key Laboratory of Networking and Switching Technology | Huang Z.,Province Key Laboratory of Software in Computing and Communication | Ji Y.,Japan National Institute of Information and Communications Technology | And 3 more authors.
2012 International Conference on Wireless Communications and Signal Processing, WCSP 2012 | Year: 2012

To achieve a higher data transmission rate, carrier aggregation (CA) technology has been included in the LTE Advanced standard. Allocating resources with CA is a crucial and challenging task due to the different types of user equipment (UE) that have different bandwidth capacities and operate under the same base station (BS). We have formulated the downlink resource allocation problem joining both carrier component (CC) allocation and resource block (RB) allocation to achieve proportional fairness in the long term. We also develop a maximum system utility (MSU) algorithm. Each time this algorithm tries to allocate the best CC to an narrow-band UE in which the number of CCs it is assigned does not exceed the number of CCs supported, maximizing the total utility until it can no longer grow. Importantly, NB UEs which can support more than one CCs are considered in this paper. Simulation results show that the proposed algorithm can significantly improve total throughput compared with the existing algorithm both with and without fairness consideration. © 2012 IEEE.


Li Q.,Hefei University of Technology | Li J.,Hefei University of Technology | Wang J.,Hefei University of Technology | Zhao B.,Anhui University of Science and Technology | And 3 more authors.
Microprocessors and Microsystems | Year: 2012

The expressive power of regular expressions has been often adopted in network intrusion detection systems, virus scanners, and spam filtering applications. However in the CPU based systems, pattern matching is one of the most computation intensive parts. In this paper, we present the design, implementation and evaluation of a regular expression string matching processing unit (SMPU). This special purpose processor is a parallel and pipelined architecture which can deal with the regular expression semantics. Two hardware stacks are implemented in SMPU to support fast branches when the non-matching occurs. Our implementation processes four characters per clock cycle (maximum performance of state of the art solutions) and occupies only O(n) memory (where n is the length of the regular expression) via synthesizing the verilog description and analyzing area/time constraints, SMPU can achieve 200-400 times speedup over traditional CPU implementations and up to 7.9 Gbps in processing throughput. Besides it outperforms the counterparts greatly as the complexity of regular expressions increases. © 2012 Elsevier B.V. All rights reserved.


Jin J.,Hefei University of Technology | Jin J.,State Key Laboratory of Networking and Switching Technology | Jin J.,Province Key Laboratory of Software in Computing and Communication | Zhao B.,Hefei University of Technology | And 5 more authors.
Chinese Journal of Electronics | Year: 2010

To minimize the length of scheduling and guarantee the load balance of channels, a Load-balanced and length-minimized link scheduling (LBLM) algorithm is proposed. LBLM algorithm is a heuristic scheme, which assigns time slots for unicast traffic based on link's weight and hop-count in the routing traffic tree. Thus the algorithm considers both primary and secondary interference, as well as guarantees the proportional fairness. The ns2 simulation results show that in multi-channel TDMA Wireless mesh networks (WMNs), the proposed algorithm has the benefits of lower complexity, shorter frame length and better channel balance compared to other well-known schedule mechanisms.


Liu F.,Hefei University of Technology | Liu F.,State Key Laboratory of Networking and Switching Technology | Liu F.,Province Key Laboratory of Software in Computing and Communication | Zhou H.,Hefei University of Technology | And 5 more authors.
Journal of University of Science and Technology of China | Year: 2010

In view of the existence of slightly curved surfaces and local minima problems with the application of the BP neural network algorithm, ergodic BP algorithm based on minimal point escape was proposed to achieve better convergence effect. The improved BP algorithm was applied to the wireless network intrusion detection system. Experiments show that, the improved BP algorithm enhances the accuracy and real time of intrusion detection systems.


Zhao X.,Hefei University of Technology | Zhao X.,Province Key Laboratory of Software in Computing and Communication | Zhou H.,Hefei University of Technology | Zhou H.,Province Key Laboratory of Software in Computing and Communication | And 4 more authors.
Hsi-An Chiao Tung Ta Hsueh/Journal of Xi'an Jiaotong University | Year: 2014

To improve the quality of service in Video on Demand(VoD) system, reduce delay and improve user experience, by combining network coding with video collaborative placement, the problem of maximum local hits is discussed, and an algorithm named MHPS is proposed. In terms of network coding, the videos are divided into segments in advance, and the clients can decode the video with enough segments. The algorithm constructs a placement graph and converts the original problem as the minimum cost flow over the graph. Thus the optimal solution can be obtained in the polynomial time complexity. The extensive simulations are carried out to evaluate the performance of the proposed algorithm. The results suggest that the proposed algorithm outperforms the other existing solutions with 10% improvement when the total size of videos is close to that of server capacity. The influence of the segment size in the algorithm is also analyzed.

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