Wei Liu

University of Florida, Gainesville, FL, United States

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Publications (30)20.83 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: This paper addresses energy conservation, a funda- mental issue of paramount importance in heterogeneous mobile ad hoc networks (MANETs) consisting of powerful nodes (i.e., P-nodes) as well as normal nodes (i.e., B-nodes). By utilizing the inherent device heterogeneity, we propose a cross-layer de- signed Device-Energy-Load Aware Relaying framework, named DELAR, to achieve energy conservation from multiple facets, including power-aware routing, transmission scheduling and power control. In particular, we design a novel power-aware routing protocol that nicely incorporates device heterogeneity, nodal residual energy information and nodal load status to save energy. In addition, we develop a hybrid transmission schedul- ing scheme, which is a combination of reservation-based and contention-based medium access control schemes, to coordinate the transmissions. Moreover, the novel notion of "mini-routing" is introduced into the data link layer and an Asymmetric MAC (A-MAC) scheme is proposed to support the MAC-layer ac- knowledgements over unidirectional links caused by asymmetric transmission power levels between powerful nodes and normal nodes. Furthermore, we present a multi-packet transmission scheme to improve the end-to-end delay performance. Extensive simulations show that DELAR can indeed achieve energy saving while striking a good balance between energy efficiency and other network performance metrics.
    IEEE Journal on Selected Areas in Communications 01/2011; 29:1572-1584. · 3.12 Impact Factor
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    ABSTRACT: Wireless sensor networks (WSNs) are appealing in obtaining fine-granular observations about the physical world. Due to the fact that WSNs are composed of a large number of low-cost but energy-constrained sensor nodes, along with the notorious time-varying and error-prone nature of wireless links, scalable, robust, and energy-efficient data disseminating techniques are requisite for the emerging WSN applications such as environment monitoring and surveillance. To meet this challenging demand, we propose a hybrid data dissemination framework for WSNs in this paper. In particular, we conceptually partition a whole sensor field into several functional regions and apply different routing schemes to different regions in order to provide better performance in terms of reliability and fair energy usage. For this purpose, we also propose a novel zone flooding scheme, essentially a combination of geometric routing and flooding techniques. Our scheme features low overhead, high reliability, good scalability, and notable flexibility. Simulation studies are carried out to validate the effectiveness and efficiency of our scheme.
    Global Telecommunications Conference, 2004. GLOBECOM '04. IEEE; 01/2010
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    ABSTRACT: We propose and investigate the SPREAD scheme as a complementary mechanism to enhance secure data deliv- ery in a mobile ad hoc network. The basic idea is to transform a secret message into multiple shares, and then deliver the shares via multiple paths to the destination so that even if a certain number of message shares are compromised, the secret message as a whole is not compromised. We present the overall system architecture and discuss three major de- sign issues: the mathematical model for the generation and reconstruction of the secret message shares, the optimal allo- cation of the message shares onto multiple paths in terms of security, and the multipath discovery techniques in a mobile
    Wireless Networks 01/2009; 15:279-294. · 0.74 Impact Factor
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    ABSTRACT: The proper functioning of mobile ad hoc networks depends on the hypothesis that each individual node is ready to forward packets for others. This common assumption, however, might be undermined by the existence of selfish users who are reluctant to act as packet relays in order to save their own resources. Such non-cooperative behavior would cause the sharp degradation of network throughput. To address this problem, we propose a credit-based Secure Incentive Protocol (SIP) to stimulate cooperation among mobile nodes with individual interests. SIP can be implemented in a fully distributed way and does not require any pre-deployed infrastructure. In addition, SIP is immune to a wide range of attacks and is of low communication overhead by using a Bloom filter. Detailed simulation studies have confirmed the efficacy and efficiency of SIP.
    Wireless Networks 01/2007; 13:569-582. · 0.74 Impact Factor
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    ABSTRACT: This paper studies key management, a fundamental problem in securing mobile ad hoc networks (MANETs). We present IKM, an ID-based key management scheme as a novel combination of ID-based and threshold cryptography. IKM is a certificateless solution in that public keys of mobile nodes are directly derivable from their known IDs plus some common information. It thus eliminates the need for certificate-based authenticated public-key distribution indispensable in conventional public-key management schemes. IKM features a novel construction method of ID-based public/private keys, which not only ensures high-level tolerance to node compromise, but also enables efficient network-wide key update via a single broadcast message. We also provide general guidelines about how to choose the secret-sharing parameters used with threshold cryptography to meet desirable levels of security and robustness. The advantages of IKM over conventional certificate-based solutions are justified through extensive simulations. Since most MANET security mechanisms thus far involve the heavy use of certificates, we believe that our findings open a new avenue towards more effective and efficient security design for MANETs
    IEEE Transactions on Dependable and Secure Computing 11/2006; 3(4):386-399. · 1.06 Impact Factor
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    ABSTRACT: The shared wireless medium of mobile ad hoc networks facilitates passive, adversarial eavesdropping on data communications whereby adversaries can launch various devastating attacks on the target network. To thwart passive eavesdropping and the resulting attacks, we propose a novel anonymous on-demand routing protocol, termed MASK, which can accomplish both MAC-layer and network-layer communications without disclosing real IDs of the participating nodes under a rather strong adversary model. MASK offers the anonymity of senders, receivers, and sender-receiver relationships in addition to node unlocatability and untrackability and end-to-end flow untraceability. It is also resistant to a wide range of attacks. Moreover, MASK preserves the high routing efficiency as compared to previous proposals. Detailed simulation studies have shown that MASK is highly effective and efficient
    IEEE Transactions on Wireless Communications 10/2006; · 2.42 Impact Factor
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    ABSTRACT: The recent Federal Communications Commission regulations for ultra-wideband (UWB) transmission systems have sparked a surge of research interests in the UWB technology. One of the important application areas of UWB is wireless sensor networks. The proper operations of many UWB sensor networks rely on the knowledge of physical sensor locations. However, most existing localization algorithms developed for sensor networks are vulnerable to attacks in hostile environments. As a result, attackers can easily subvert the normal functionalities of location-dependent sensor networks by exploiting the weakness of localization algorithms. In this paper, we first analyze the security of existing localization techniques. We then develop a mobility-assisted secure localization scheme for UWB sensor networks. In addition, we propose a location-based scheme to enable secure authentication in UWB sensor networks.
    IEEE Journal on Selected Areas in Communications 05/2006; · 3.12 Impact Factor
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    ABSTRACT: Node compromise is a serious threat to wireless sensor networks deployed in unattended and hostile environments. To mitigate the impact of compromised nodes, we propose a suite of location-based compromise-tolerant security mechanisms. Based on a new cryptographic concept called pairing, we propose the notion of location-based keys (LBKs) by binding private keys of individual nodes to both their IDs and geographic locations. We then develop an LBK-based neighborhood authentication scheme to localize the impact of compromised nodes to their vicinity. We also present efficient approaches to establish a shared key between any two network nodes. In contrast to previous key establishment solutions, our approaches feature nearly perfect resilience to node compromise, low communication and computation overhead, low memory requirements, and high network scalability. Moreover, we demonstrate the efficacy of LBKs in counteracting several notorious attacks against sensor networks such as the Sybil attack, the identity replication attack, and wormhole and sinkhole attacks. Finally, we propose a location-based threshold-endorsement scheme, called LTE, to thwart the infamous bogus data injection attack, in which adversaries inject lots of bogus data into the network. The utility of LTE in achieving remarkable energy savings is validated by detailed performance evaluation.
    IEEE Journal on Selected Areas in Communications 03/2006; · 3.12 Impact Factor
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    ABSTRACT: Efficient routing is very important for mobile ad hoc networks (MANETs). Most existing routing protocols consider homogeneous ad hoc networks, in which all nodes are identical, i.e., they have the same communication capabilities and characteristics. Although a homogeneous network model is simple and easy to analyze, it misses important characteristics of many realistic MANETs such as military battlefield networks. In addition, a homogeneous ad hoc network suffers from poor performance limits and scalability. In many ad hoc networks, multiple types of nodes do coexist; and some nodes have larger transmission power, higher transmission data rate, better processing capability, and are more robust against bit errors and congestion than other nodes. Hence, a heterogeneous network model is more realistic and provides many advantages (e.g., leading to more efficient routing protocol design). In this paper, we present a new routing protocol called multiclass (MC) routing, which is specifically designed for heterogeneous MANETs. Moreover, we also design a new medium access control (MAC) protocol for heterogeneous MANETs, which is more efficient than IEEE 802.11b. Extensive simulation results demonstrate that the MC routing has very good performance, and outperforms a popular routing protocol-zone routing protocol, in terms of reliability, scalability, route discovery latency, overhead, as well as packet delay and throughput.
    IEEE Transactions on Vehicular Technology 02/2006; · 2.06 Impact Factor
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    ABSTRACT: Wireless sensor networks (WSNs) are appealing in obtaining ne-granular observations about the physical world. Due to the fact that WSNs are composed of a large number of low-cost and energy-constrained sensor nodes, along with the notorious time- varying and error-prone nature of wireless links, scalable, robust and energy-efcient data dissemination techniques are needed for the emerging WSN applications such as environment monitoring and surveillance. In this paper, we examine this emerging eld from the point of view of supply chain management and propose a hybrid data dissemination framework for WSNs. In particular, for each sensing task, the whole sensor eld is conceptually partitioned into several functional regions based on the supply chain management methodology. Different routing schemes are applied to different regions in order to provide better performance in terms of reliability and energy consumption. For this purpose, we also propose a novel zone ooding scheme, essentially a combination of conventional geometric routing and ooding techniques. Our hybrid data dissemination framework features low overhead, high reliability, good scalability and e xibility, and preferable energy efcienc y. Detailed simulation studies are carried out to validate the effectiveness and efcienc y of our scheme.
    Wireless Networks 01/2006; 12:465-479. · 0.74 Impact Factor
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    ABSTRACT: Energy conservation in mobile ad hoc networks is of paramount importance be- cause most mobile nodes usually have very limited energy supply. Previous research on this issue focused on the design at the network or MAC or physical layer. In this paper, we study this problem from the new perspective of node mobility, i.e., analyzing the impact of node movement on energy conservation. In particular, armed with the inherent resource hetero- geneity in mobile ad hoc networks, we propose a novel resource-aware movement strategy to make better use of some powerful nodes to achieve energy conservation. We also formu- late the resource-aware movement as a NP-complete distance-constrained least-cost (DCLC) routing problem and propose an efficient heuristic solution. Extensive simulations have been used to demonstrate the effectiveness of the proposed schemes.
    Journal of Combinatorial Optimization 01/2006; 11:7-20. · 0.59 Impact Factor
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    ABSTRACT: We propose an innovative resource management scheme for TDMA based mobile ad hoc networks. Since communications between some important nodes in the network are more critical, they should be accepted by the network with high priority in terms of network resource usage and quality of service (QoS) support. In this scheme, we design a location-aware bandwidth pre-reservation mechanism, which takes advantage of each mobile node’s geographic location information to pre-reserve bandwidth for such high priority connections and thus greatly reduces potential scheduling conflicts for transmissions. In addition, an end-to-end bandwidth calculation and reservation algorithm is proposed to make use of the pre-reserved bandwidth. In this way, time slot collisions among different connections and in adjacent wireless links along a connection can be reduced so that more high priority connections can be accepted into the network without seriously hurting admissions of other connections. The salient feature of our scheme is the collaboration between the routing and MAC layer that results in the more efficient spatial reuse of limited resources, which demonstrates how cross-layer design leads to better performance in QoS support. Extensive simulations show that our scheme can successfully provide better communication quality to important nodes at a relatively low price. Finally, several design issues and future work are discussed.
    Wireless Networks 01/2006; 12:797-812. · 0.74 Impact Factor
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    ABSTRACT: Multipath routing has been a promising technique in MANETs and WSNs. It has been shown through both theoretical analysis and simulation results that multipath routing provides many performance benefits, including improved fault tolerance, security, and reliability, improved routing efficiency and reduced routing overhead, more balanced traffic load and energy consumption, reduced end-to-end latency, and aggregated network bandwidth, etc. Significant research efforts have been made and are continuously being made in developing multipath routing protocols and multipath packet forwarding techniques in order to achieve the above-mentioned performance gains effectively and efficiently. Nevertheless, many issues that are directly related to the application of multipath routing remain untouched, such as the integration of the multipath routing into the current single-path routing paradigm, the synchronization of the packets among the multiple paths, and the interfaces of multipath routing protocols to other layers of protocol in the network protocol stack, etc. Due to space limitations, we are only able to introduce the basic concept of multipath routing, highlight the fundamental techniques used to find the multiple paths, and outline the essential idea of what and why it can help in performance. For detailed algorithms/protocols as well as performance evaluations, interested readers are referred to respective publications.
    12/2005: pages 117-146;
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    ABSTRACT: Energy condensation is a crucial issue in mobile ad hoc networks (MANETs). In our previous work, we have proposed a device-energy-load aware relaying framework (DELAR) (2004) that can effectively utilize some powerful nodes (P-nodes) to conserve energy for other common nodes (B-nodes) and in turn prolong the network lifetime. DELAR is a joint design of power control, routing, and scheduling. Moreover, in this framework, an asymmetric MAC (A-MAC) is adopted to support reliable communications on unidirectional links caused by asymmetric transmission power between the involved transmitter and receiver. Grounded on this DELAR framework which emphasizes the interaction between the MAC layer and the network layer, in this paper we further take into account the physical layer and propose a multiple-packets transmission scheme which is jointly operated with hierarchical modulation to further improve the energy efficiency and shorten the packet delay. The basic idea is to enable such P-nodes to transmit multiple packets towards different receivers in one transmission, and this transmission is implemented with hierarchical modulation to ensure sufficient SNR at all the receivers to demodulate their corresponding packets. Simulation results validate the effectiveness and efficiency of this multiple-packets transmission scheme. It can further improve the energy efficiency and greatly shorten the packet delay
    Military Communications Conference, 2005. MILCOM 2005. IEEE; 11/2005
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    ABSTRACT: Ad hoc wireless sensor networks (WSNs) have attracted a great deal of attention in recent years for their broad potential in both military and civilian operations. The proper operations of many WSNs rely on the knowledge of physical sensor locations. However, most existing localization algorithms developed for WSNs are vulnerable to attacks in hostile environments. As a result, adversaries can easily subvert the normal functionalities of location-dependent WSNs by exploiting the weakness of localization algorithms. In this paper, we first present a general secure localization scheme to protect localization from adversarial attacks. We then propose a mobility-assisted secure localization framework for WSNs.
    Military Communications Conference, 2005. MILCOM 2005. IEEE; 11/2005
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    ABSTRACT: This paper studies public-key management, a fundamental problem in providing security support for mobile ad hoc networks. The infrastructureless nature and network dynamics of ad hoc networks make the conventional certificate-based public-key solutions less suitable. To tackle this problem, we propose a novel anonymous and certificateless public-key infrastructure (AC-PKI) for ad hoc networks. AC-PKI enables public-key services with certificateless public keys and thus avoids the complicated certificate management inevitable in conventional certificate-based solutions. To satisfy the demand for private keys during network operation, we employ the secret-sharing technique to distribute a system master-key among a preselected set of nodes, called D-PKG, which offer a collaborative private-key-generation service. In addition, we identify pinpoint attacks against D-PKG and propose anonymizing D-PKG as the countermeasure. Moreover, we determine the optimal secret-sharing parameters to achieve the maximum security.
    Communications, 2005. ICC 2005. 2005 IEEE International Conference on; 06/2005
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    ABSTRACT: Wireless sensor networks are often deployed in unattended and hostile environments, leaving individual sensors vulnerable to security compromise. The paper proposes the novel notion of location-based keys for designing compromise-tolerant security mechanisms for sensor networks. Based on location-based keys, we develop a node-to-node authentication scheme, which is able not only to localize the impact of compromised nodes within their vicinity, but also to facilitate the establishment of pairwise keys between neighboring nodes. Compared with previous proposals, our scheme has perfect resilience against node compromise, low storage overhead, and good network scalability. We also demonstrate the use of location-based keys in combating a few notorious attacks against sensor network routing protocols.
    Wireless Communications and Networking Conference, 2005 IEEE; 04/2005
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    ABSTRACT: Due to the broadcast nature of radio transmissions, communications in mobile ad hoc networks (MANETs) are more susceptible to malicious traffic analysis. In this paper we propose a novel anonymous on-demand routing protocol, termed MASK, to enable anonymous communications thereby thwarting possible traffic analysis attacks. Based on a new cryptographic concept called pairing, we first propose an anonymous neighborhood authentication protocol which allows neighboring nodes to authenticate each other without revealing their identities. Then utilizing the secret pairwise link identifiers and keys established between neighbors during the neighborhood authentication process, MASK fulfills the routing and packet forwarding tasks nicely without disclosing the identities of participating nodes under a rather strong adversarial model. MASK provides the desirable sender and receiver anonymity, as well as the relationship anonymity of the sender and receiver. It is also resistant to a wide range of adversarial attacks. Moreover, MASK preserves the routing efficiency in contrast to previous proposals. Detailed anonymity analysis and simulation studies are carried out to validate and justify the effectiveness of MASK.
    INFOCOM 2005. 24th Annual Joint Conference of the IEEE Computer and Communications Societies. Proceedings IEEE; 04/2005
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    ABSTRACT: It is well known that the Delay-Constrained Least-Cost (DCLC) unicast routing problem is NP-complete, hence various heuristic algorithms have been developed for this problem. In this paper, we propose a more efficient distributed algorithm, namely, Selection-Function-based DCLC (SF-DCLC), based on a novel selection function for the DCLC problem. The proposed SF-DCLC algorithm requires limited network state information at each node and is always able to find a loop-free path satisfying the delay bound if such paths exist. Simulation study shows that SF-DCLC is not as sensitive to the delay bound and the size of networks as some other DCLC routing algorithms, and has very low cost-inefficiency compared to the optimal one in various network scenarios we have studied. A noteworthy feature of SF-DCLC is that SF-DCLC has very high probability of finding the optimal solution in polynomial time with low computational complexity and message complexity.
    Computer Networks. 01/2005;
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    ABSTRACT: Wireless sensor networks (WSNs) are appealing in obtaining fine-granular observations about the physical world. Due to the fact that WSNs are composed of a large number of low-cost but energy-constrained sensor nodes, along with the notorious timer-varying and error-prone natures of wireless links, scalable, robust, and energy-efficient data disseminating techniques are requisite for the emerging WSN applications such as environment monitoring and surveillance. In this paper we examine this emerging field from a view of supply chain management and propose a hybrid data dissemination framework for WSNs. In particular, we conceptually partition a whole sensor field into several functional regions based on the supply chain management methodology, and apply different routing schemes to different regions in order to provide better performance in terms of reliability and energy usage. For this purpose, we also propose a novel zone flooding scheme, essentially a combination of geometric routing and flooding techniques. Our hybrid data dissemination framework features low overhead, high reliability, good scalability and flexibility, and preferable energy efficiency. Detailed simulation studies are carried out to validate the effectiveness and efficiency of our scheme.
    Quality of Service in Heterogeneous Wired/Wireless Networks, 2004. QSHINE 2004. First International Conference on; 11/2004

Publication Stats

793 Citations
20.83 Total Impact Points

Institutions

  • 2003–2010
    • University of Florida
      • Department of Electrical and Computer Engineering
      Gainesville, FL, United States
  • 2006
    • New Jersey Institute of Technology
      • Department of Electrical and Computer Engineering
      Newark, NJ, United States
    • North Dakota State University
      • Department of Computer Science
      Fargo, ND, United States
  • 2004–2005
    • Worcester Polytechnic Institute
      • Department of Electrical and Computer Engineering
      Worcester, MA, United States