共查询到20条相似文献,搜索用时 15 毫秒
1.
Mobile Ad hoc Networks (MANETs) rely on the cooperation of nodes for packet routing and forwarding. Much of the existing work
in MANETs assume that mobile nodes (possibly owned by selfish users) will follow prescribed protocols without deviation. However,
a user may misbehave due to several advantages resulting from noncooperation, the most obvious being power saving. As such,
the network availability is severely endangered. Hence, enforcing the cooperation among nodes becomes a very important issue.
Several different approaches have been developed to detect non-cooperative nodes or deal with the non-cooperative behavior
of mobile nodes in MANETs. These protocols are first surveyed in details in this paper. It is found that the proposed approaches
have several concerns that prevent them from really enforcing the node cooperation in MANETs. Thus, a new scheme that can
stimulate and also enforce nodes to cooperate in a selfish ad hoc environment is presented. We also present a mechanism to
detect and exclude potential threats of selfish mobile nodes. The simulation results indicate that by using the proposed scheme,
MANETs can be robust against nodes’ misbehaving and the performance of the network is enhanced many folds when compared to
other existing schemes.
相似文献
Ahmed E. KamalEmail: |
2.
Sheng-Chang Chen Chyi-Ren Dow Ren-Di Wang Yi-Hsung Li Shiow-Fen Hwang 《Wireless Personal Communications》2009,48(3):441-462
Multicasting is an essential service for mobile ad-hoc networks. A major challenge for multicasting in mobile ad-hoc networks
(MANETs) is the unstable forwarding path. This work presents a reliable multicasting protocol for mobile ad-hoc networks.
A virtual backbone is used as a shared structure for multiple sessions. A lost packet recovery scheme is developed for reliable
packet transmission, called the Recovery Point (RP) scheme. The RP scheme maintains the data packets received from the source
for recovering lost packets for its downstream RPs. In addition, we combine the Forward Error Correction (FEC) technology
with our RP scheme to enhance the reliability of our RP scheme. A mergence scheme for RP is also proposed to avoid excessive
control overhead. Our RP and FEC based scheme can be used to improve the reliability and efficiency of the traditional non-acknowledged
multicasting approach. Experiments were conducted to evaluate the proposed multicasting scheme. The results demonstrate that
our scheme outperforms other schemes in terms of packet delivery ratio and multicast efficiency. Furthermore, the simulation
results also demonstrate that our approach is stable in networks with high mobility.
相似文献
Shiow-Fen HwangEmail: |
3.
In mobile communications, effective inter-networking is mandatory in order to support user roaming among various types of
wireless networks while maintaining connectivity. In this paper, we propose a super node system architecture to achieve the
connectivity over interconnected heterogeneous wireless access networks, which employs the delay-tolerant network (DTN) concept
to overcome the problem of potential intermittent connections caused by user roaming and ensures message delivery in the presence
of a long disconnection period. By introducing the concept of virtual network topology, we present a new routing technique
for mobile ad hoc networks (MANETs) within the system architecture, which redefines the dominating-set based routing for the
challenged network environment. A time based methodology is presented to predict the probability of future contacts between
node pairs for constructing the virtual network topology. Simulation results demonstrate the effectiveness of the proposed
dominating-set based routing scheme under the DTN system architecture.
相似文献
Bruno PreissEmail: |
4.
Víctor P. Gil Jiménez Thomas Eriksson Ana García Armada M. Julia Fernández-Getino García Tony Ottosson Arne Svensson 《Wireless Personal Communications》2008,47(1):101-112
In this paper, several algorithms for compressing the feedback of channel quality information are presented and analyzed.
These algorithms are developed for a proposed adaptive modulation scheme for future multi-carrier 4G mobile systems. These
strategies compress the feedback data and, used together with opportunistic scheduling, drastically reduce the feedback data
rate. Thus the adaptive modulation schemes become more suitable and efficient to be implemented in future mobile systems,
increasing data throughput and overall system performance.
相似文献
Arne SvenssonEmail: |
5.
Shuigen Yang Hongbin Luo Yajuan Qin Hongke Zhang 《Wireless Personal Communications》2009,48(4):605-619
Host Identity Protocol (HIP) is designed to provide secure and continuous communication by separating the identifier and locator
roles of the Internet Protocol (IP) address. HIP also has efficient solutions to support host mobility. In this paper, we
propose a location management scheme based on Domain Name System (DNS) for HIP. In the proposed scheme, a new DNS HIP resource
record is used to translate a domain name into a host identity tag and an IP address. We also develop an analytical model
to study the performance of DNS as location manager in terms of success rate, which takes into account the velocity of mobile
nodes, the radius of a subnet, the regional network size, the packet transmission delay between the mobile node and the rendezvous
server, and the packet processing delay at the DNS and the rendezvous server. The performance results show that for a reasonable
range, the DNS is a feasible solution for location management with high success rate for HIP.
相似文献
Hongke ZhangEmail: |
6.
Efficient routing and medium access control (MAC) are very important for Mobile Ad hoc Networks (MANETs). Most existing routing
and MAC protocols consider homogeneous ad hoc networks, in which all nodes are modeled as the same, 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 ad hoc networks. In addition, a homogeneous
ad hoc network suffers from poor performance and scalability. In many ad hoc networks, multiple types of nodes do co-exist;
and some nodes have larger transmission power, higher transmission data rate, and better processing capability, are more reliable
and robust than other nodes. Hence, a hybrid network model is more realistic and provides many advantages for designing better
routing and MAC protocols. In this paper, we present a new routing protocol called Hybrid Routing, which is specifically designed
for hybrid MANETs. In addition, a novel MAC protocol is jointly designed for hybrid MANETs. Extensive simulations demonstrate
that the proposed routing MAC protocols have very good performance.
相似文献
Dapeng Wu (Corresponding author)Email: URL: http://www.wu.ece.ufl.edu |
7.
In mobile orthogonal frequency division multiplexing (OFDM) systems, time-varying channels result in severe intercarrier interference
(ICI), and greatly degrade the system performance. So, it is necessary to estimate the accurate channel for equalization of
received symbols. But, the conventional pilot-assisted channel estimation scheme consumes valuable bandwidth. In this paper,
we adopt superimposed training approach for OFDM systems to estimate the time-varying channel, which is approximated by a
basis expansion model (BEM). The proposed scheme is an extension of the superimposed training approach previously proposed
for time-invariant channels in OFDM systems. At the same time, we employ an iterative best linear unbiased estimator (BLUE)
to minimize the mean square error (MSE) of the coefficient estimates and improve the system performance. Simulation results
prove the effectiveness of the proposed scheme in fast time-varying scenario.
相似文献
Wen QinEmail: |
8.
Qing Liu Chongyang Xie Tannous Frangieh Nasir Ghani Ashwin Gumaste Nageswara S. V. Rao 《Photonic Network Communications》2009,17(1):63-74
This paper studies routing scalability in multi-domain DWDM networks. Although inter-domain provisioning has been well studied
for packet/cell-switching networks, the wavelength dimension (along with wavelength conversion) poses many challenges in multi-domain
DWDM settings. To address these concerns a detailed GMPLS-based hierarchical routing framework is proposed for multi-domain
DWDM networks with wavelength conversion. This solution uses mesh topology abstraction schemes to hide domain-internal state.
However related inter-domain routing loads can be significant here, growing by the square of the number of border nodes. To
address these scalability limitations, improved inter-domain routing update strategies are also proposed and the associated
performance of inter-domain lightpath RWA and signaling schemes studied.
相似文献
Nasir GhaniEmail: |
9.
Grzegorz Mrugalski Janusz Rajski Chen Wang Artur Pogiel Jerzy Tyszer 《Journal of Electronic Testing》2007,23(1):35-45
This paper describes a non-recursive fault diagnosis technique for scan-based designs with convolutional test response compaction.
The proposed approach allows a time-efficient and accurate identification of failing scan cells using Gauss–Jordan elimination
method.
相似文献
Jerzy Tyszer (Corresponding author)Email: |
10.
This paper presents the design and evaluation of a highly efficient on-demand multicast routing protocol for mobile ad hoc
networks (MANETs). The protocol, called Geography-aided Multicast Zone Routing Protocol (GMZRP), eliminates as much as possible
duplicate route queries by using a simple yet effective strategy for propagating the multicast route request (MRREQ) packets.
GMZRP is the first hybrid multicast protocol taking the advantages of both topological routing and geographical routing. It
partitions the network coverage area into small zones and guarantees that each geographic zone is queried only once. GMZRP
maintains a multicast forwarding tree at two levels of granularities, i.e., the zone granularity and the node granularity.
By doing this, it can easily handle route breakage since the zone level information can help recover the link failure at the
node level. The results of the performance evaluation of GMZRP using simulation show that, comparing with the well-known multicast
protocol ODMRP (On-Demand Multicast Routing Protocol), GMZRP has much lower protocol overhead in terms of query packets and,
meanwhile, achieves competing packet delivery ratio and shorter delivery latency.
相似文献
Xiaopeng FanEmail: |
11.
Benson S. Y. Lam Alan Wee-Chung Liew David K. Smith Hong Yan 《Journal of Signal Processing Systems》2008,50(3):281-292
Microarray data clustering has drawn great attention in recent years. However, a major problem in data clustering is convergence
to a local optimal solution. In this paper, we introduce a regularized version of the l
2m-FCM algorithm to resolve this problem. The strategy is to constrain the descent direction in the optimization procedure.
For this we employ a novel method, calculus of variations, to correct the direction. Experimental results show that the proposed
method has a better performance than seven other clustering algorithms for three synthetic and six real world data sets. Also,
the proposed method produces reliable results for synthetic data sets with a large number of groups, which is a challenging
problem for many clustering algorithms. Our method has been applied to microarray data classification with good results.
相似文献
Hong YanEmail: |
12.
Li-Der Chou Jui-Ming Chen Hung-Sheng Kao Shao-Feng Wu Wayne Lai 《Mobile Networks and Applications》2006,11(6):873-887
As the mobile networking technologies evolve, people are able to access the Internet through heterogeneous wireless access
networks, such as WLAN, GPRS, 3G and Beyond 3G networks. For the coverage, bandwidth and cost of these heterogeneous mobile
access networks are quite different, a mobile host may hand over among them, and this is called vertical handoffs. One of
the most important issues for heterogeneous mobile networks is that vertical handoffs may degrade the quality of the time-sensitive
streaming media services, even interrupt them. To overcome the problem, in the paper a multicast-based redundant streaming
architecture is proposed. The proposed architecture is implemented in the all-IPv6 heterogeneous mobile networks. Five experiments
are performed to evaluate the performance of the proposed architecture. The experimental results and the analysis show that
the proposed architecture is capable of providing seamless streaming services even if the vertical handoffs or the traffic
congestion occurs. Moreover, it is found that the traffic overhead is only 1.0368% per vertical handoff for each mobile access
network, and thus the feasibility of the proposed architecture is demonstrated.
相似文献
Jui-Ming ChenEmail: |
13.
A peak-to-average power ratio (PAPR) reduction scheme with low complexity is proposed for the multicarrier spread spectrum
(MC-SS) system in personal area network (PAN). Traditional clipping and filtering scheme requires a high oversampling rate
to meet the emission mask requirements. This would cause high power consumption for mobile PAN devices in personal network.
To solve the problem, upsampling is introduced between clipping and filtering in this paper to reduce the oversampling rate.
A simplified implementation structure is also derived for the proposed scheme. Simulation results show that its complexity
is about 65% of the conventional scheme while achieving satisfying performance.
相似文献
Lu RongEmail: |
14.
15.
This article advocates a novel communication architecture and associated collaborative framework for future wireless communication
systems. In contrast to the dominating cellular architecture and the upcoming peer-to-peer architecture, the new approach
envisions a cellular controlled short-range communication network among cooperating mobile and wireless devices. The role
of the mobile device will change, from being an agnostic entity in respect to the surrounding world to a cognitive device.
This cognitive device is capable of being aware of the neighboring devices as well as on the possibility to establish cooperation
with them. The novel architecture together with several possible cooperative strategies will bring clear benefits for the
network and service providers, mobile device manufacturers and also end users.
相似文献
Qi ZhangEmail: |
16.
Paolo Costa Geoff Coulson Cecilia Mascolo Luca Mottola Gian Pietro Picco Stefanos Zachariadis 《International Journal of Wireless Information Networks》2007,14(2):149-162
Next generation embedded systems will be composed of large numbers of heterogeneous devices. These will typically be resource-constrained
(such as sensor motes), will use different operating systems, and will be connected through different types of network interfaces.
Additionally, they may be mobile and/or form ad-hoc networks with their peers, and will need to be adaptive to changing conditions
based on context-awareness. Our focus in this paper is on the provision of a middleware framework for such system environments.
Our approach is based on a small and efficient ‘middleware kernel’ which supports highly modularised and customisable component-based
middleware services that can be tailored for specific embedded environments, and are runtime reconfigurable to support adaptivity.
These services are primarily communications-related but also address a range of other concerns including service discovery
and logical mobility. In the paper we provide an overview of our approach, focusing in detail on both the middleware kernel
and the services. We also discuss an application scenario in which we are currently applying and evaluating our middleware
approach.
相似文献
Stefanos ZachariadisEmail: |
17.
The next generation of wireless mobile communications termed beyond 3G (or 4G), will be based on a heterogeneous infrastructure
that comprises different wireless networks in a complementary manner. Beyond 3G will introduce reconfiguration capabilities
to flexibly and dynamically (i.e., during operation) adapt the wireless protocol stacks to better meet the ever-changing service
requirements. For the dynamic reconfiguration of protocol stacks during runtime operation to become a practical capability
of mobile communication systems, it is necessary to establish a software architecture that functionally supports reconfiguration.
In the present paper, a generic architecture and respective mechanisms to achieve protocol stack and component based protocol
layer reconfiguration are proposed.
相似文献
Vangelis GazisEmail: |
18.
Elliptic curve cryptography (ECC) is recognized as a fast cryptography system and has many applications in security systems.
In this paper, a novel sharing scheme is proposed to significantly reduce the number of field multiplications and the usage
of lookup tables, providing high speed operations for both hardware and software realizations.
相似文献
Brian KingEmail: |
19.
Sakib A. Mondal 《Wireless Networks》2009,15(3):331-340
Mobile IP is a network layer protocol for handling mobility of hosts in the Internet. However, mobile IP handoff causes degradation
of TCP performance. Hence, there is a need for improving performance of TCP over mobile IP in wireless mobile networks. We
propose an approach which handles losses due to both wireless link errors and host mobility. To handle losses due to host
mobility, a method for seamless handoff is proposed. Empirical results show that the scheme provides substantial improvement
of performance.
Sakib A. Mondal is a Senior Researcher at General Motors Research. He has received his doctorate in Management Information Systems from Indian Institute of Management Calcutta, and has worked for almost twelve years in various areas of Information Technology. His research interests include mobile and distributed computing, performance engineering, optimization and heuristic search. 相似文献
Sakib A. MondalEmail: |
Sakib A. Mondal is a Senior Researcher at General Motors Research. He has received his doctorate in Management Information Systems from Indian Institute of Management Calcutta, and has worked for almost twelve years in various areas of Information Technology. His research interests include mobile and distributed computing, performance engineering, optimization and heuristic search. 相似文献
20.
This paper presents the evaluation of the average spectral efficiencies provided by the adaptive use of a set of LDPC-coded
QAM modulations in an OFDMA downlink scheme over mobile radio channels, considering a joint modeling of the channel and user-access
method. It discusses the selection of the set of coded modulations, briefly describes the joint modeling of the channel and
access method employed, and derives the average spectral efficiency provided by this approach in non-ARQ or H-ARQ environments.
Some comments about the effects of the system’s parameters upon its performances are also included.
相似文献
Vasile BotaEmail: |