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1 – 10 of 78Linli Cui, Zhenhai Shao, Tian Zhou and Aiyun Li
The purpose of this paper is to introduce a resource allocation mechanism for Multimedia Broadcast/Multicast Service (MBMS) in a wireless cellular system and to obtain a rapid and…
Abstract
Purpose
The purpose of this paper is to introduce a resource allocation mechanism for Multimedia Broadcast/Multicast Service (MBMS) in a wireless cellular system and to obtain a rapid and efficient transmission scheme over various types' services. The proposed algorithm is evaluated by simulation results.
Design/methodology/approach
A big problem for wireless communication is the limited time/frequency resources. Therefore, the most important issue is how to utilize these limited resources to transmit various services over a wireless broadband network, especially for MBMS services. In this paper, resource allocation mechanism in a full unicast system is first analyzed with three classical methods, then improved modulation and coding schemes (MCS) methods are proposed in a full multicast system to improve system throughput and spectral efficiency. Based on the foregoing discussions, research on resource allocation mechanism for mixed multicast and unicast traffic is developed in single‐cell and multi‐cell system (MBSFN, MBMS over single frequency network), respectively. Different transmission proportions between multicast and unicast are analyzed and a multiplexing scenario is also considered.
Findings
Resource allocation is a hot topic in wireless communication and there are many investigations on it. However, resource allocation for multicast system, especially for mixed multicast and unicast traffic system, is still a problem worthy of further study. Under same transmission condition in a single cell scenario, system throughput in multicast mode is worse than in unicast mode, which is partly because the number of valid date in multicast resource block (RB) is less than the one in unicast in 3GPP LTE/LTE‐A, on the other hand, because that multicast need to select a relative low MCS to satisfy most MBMS users, even the users with a very poor transmission condition. Fortunately, multicast in MBSFN (MBMS over single frequency network) transfer mode can largely improve system performance.
Originality/value
Improved MCS selection schemes are proposed for full multicast transmission and three transmission scenarios for mixed multicast and unicast traffic are presented to discuss resource allocation mechanism over various types' services. Simulation results show that system performance of multicast system can be greatly enhanced in MBSFN transmission mode, especially with MIMO technology.
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Hong Liu, Shouhong Wang and Teng Fei
Online auctions on the Internet have become popular. However, the communication techniques currently used in the online auction industry are primarily based on unicast technology…
Abstract
Online auctions on the Internet have become popular. However, the communication techniques currently used in the online auction industry are primarily based on unicast technology. Unicast‐based online auctions suffer from unbearable delay of the communication between the auctioneer and bidders. Recently, multicast is changing the Internet environment, and is penetrating to the online auction field. This study describes a model for multicast‐based online auctions. The laboratory experiments demonstrate that the communication performance of multicast‐based online auctions is significantly better than that of traditional unicast‐based auctions.
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Lenin Mehedy, Sungyoung Lee, Salahuddin Muhammad Salim Zabir and Young‐Koo Lee
Presence of innumerable sensors, complex deduction of contexts from sensor data, and reusability of contextual information impose the requirement of middleware for context aware…
Abstract
Purpose
Presence of innumerable sensors, complex deduction of contexts from sensor data, and reusability of contextual information impose the requirement of middleware for context aware computing. Smart applications, hosted in myriad devices (e.g. PDA, mobile, PCs), acquire different contexts from the middleware and act intelligently based on the available contexts in a context‐aware computing environment. As the system grows larger, scalable delivery of contexts from the middleware to numerous context‐aware applications will be inevitable. However, pure unicast based or pure broadcast‐based dissemination cannot provide high scalability as well as low‐average latency. The purpose of this paper is to present a scalable context delivery mechanism for the middlewares to facilitate the development of larger context‐aware computing systems.
Design/methodology/approach
The proposed scheme is based on hybrid data dissemination technique where the most frequently requested data (e.g. HOT contexts) are delivered through multicast and the rest (e.g. COLD contexts) are delivered through unicast to reduce network traffic. The paper dynamically prioritizes and classifies the HOT and COLD context data depending on the number of requests and longest waiting time. Moreover, the division of bandwidth between the delivery of HOT and COLD contexts reduces average latency. Polling traffic is decreased by incorporating leasing mechanism. Extensive simulation is conducted to evaluate the proposed scheme.
Findings
The mechanism dynamically prioritizes and classifies the hot and cold context data depending on the request rate and longest waiting time. The solution addresses the push popularity problem that occurs in the passive as the passive clients access data without sending explicit requests. The leasing mechanism is incorporated to reduce the periodical requests (polling) for better performance.
Originality/value
The paper is of value in presenting a scalable context delivery mechanism for the middlewares to facilitate the development of larger context‐aware computing systems and also in presenting implementation details of a prototype that is developed using Jini framework and Java reliable multicast service (JRMS) library.
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Oussama Senouci, Zibouda Aliouat and Saad Harous
This paper is a review of a number routing protocols in the internet of vehicles (IoV). IoV emphasizes information interaction among humans, vehicles and a roadside unit (RSU)…
Abstract
Purpose
This paper is a review of a number routing protocols in the internet of vehicles (IoV). IoV emphasizes information interaction among humans, vehicles and a roadside unit (RSU), within which routing is one of the most important steps in IoV network.
Design/methodology/approach
In this paper, the authors have summarized different research data on routing protocols in the IoV. Several routing protocols for IoV have been proposed in the literature. Their classification is made according to some criteria such as topology-based, position-based, transmission strategy and network structure. This paper focuses on the transmission strategy criteria. There exist three types of protocols that are based on this strategy: unicast protocol, broadcast protocols and multicast protocols. This later type is classified into two subclasses: geocast and cluster-based protocols. The taxonomy of the transmission strategy is presented in this study. We discuss the advantages and disadvantages of each type with a general comparison between the five types.
Findings
The authors can deduce that many challenges are encountered when designing routing protocols for IoV.
Originality/value
A simple and well-explained presentation of the functioning of the IoV is provided with a comparison among each categories of protocols is well presented along with the advantages and disadvantages of each type. The authors examined the main problems encountered during the design of IoV routing protocol, such as the quick change of topology, the frequent disconnection, the big volume of data to be processed and stored in the IoV, and the problem of network fragmentation. This work explores, compares existing routing protocols in IoV and provides a critical analysis. For that, the authors extract the challenges and propose future perspectives for each categories of protocols.
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Diogo M.R. Ferreira and J.J. Pinto Ferreira
The purpose of this paper is to show how workflow management can be applied in the context of business networking.
Abstract
Purpose
The purpose of this paper is to show how workflow management can be applied in the context of business networking.
Design/methodology/approach
The paper looks at workflow management systems (WfMSs) as an enterprise integration tool and, as such, it shows that WfMS require an appropriate integration infrastructure. The paper then describes how a WfMS that supports business networking can be built.
Findings
It is found that business networking requires a decentralized, peer‐to‐peer (P2P) integration infrastructure. On the other hand, it is found that it is possible to develop a generic and reusable workflow engine. Both components are then integrated in order to come up with a solution that supports business networking.
Research limitations/implications
Issues concerning information and document management are not addressed. Neither mechanisms of storage and retrieval of exchanged documents, nor the format/structure of those documents are specified.
Practical implications
The paper assumes that enterprises will be willing to build up a P2P network where they will conduct their business‐to‐business (B2B) exchanges. Then, the proposed solution would allow their business processes to be linked without requiring tight coupling between their information systems.
Originality/value
The paper is useful to IT strategists and researchers dealing with WfMS, B2B integration architectures and applications of P2P technology.
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Group communication has become increasing important in mobile ad hoc networks (MANET). Current multicast routing protocols in MANET have been shown to incur large overheads due to…
Abstract
Purpose
Group communication has become increasing important in mobile ad hoc networks (MANET). Current multicast routing protocols in MANET have been shown to incur large overheads due to dynamic network topology. To this end, this paper proposes an overlay multicast scheme in MANET that is more efficient.
Design/methodology/approach
The approach is to construct an overlay multicast tree based on the locations of the group nodes. The paper proposes several tree construction algorithms, namely, location‐guided k‐ary (LGK) tree, location‐guided directional (LGD) tree and location‐guided Steiner (LGS) tree. All of them rely on the geometric locations of the nodes as heuristics to construct the tree. The paper also introduces several mechanisms to enhance the proposed algorithms.
Findings
The simulation results show that the location‐guided heuristics is very effective in constructing low bandwidth cost overlay multicast trees in MANET. When location information is up‐to‐date, the bandwidth cost of a LGS tree is similar to that of an optimal router‐assisted Steiner multicast tree. When location information is out‐dated, LGD tree has the lowest cost.
Originality/value
This paper demonstrates the effectiveness of location‐guided heuristics in constructing overlay multicast trees in MANET. This study strongly suggests that location‐guided heuristics can be used to design many other algorithms in a mobile network.
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Ashish Raniwala, Gefan Zhang, Ashwini Sridhar, Jian P. Zheng and Tzi‐cker Chiueh
This paper aims to describe the design, implementation, and evaluation of a novel file and application sharing system that enables a group of mobile stations that do not have any…
Abstract
Purpose
This paper aims to describe the design, implementation, and evaluation of a novel file and application sharing system that enables a group of mobile stations that do not have any prior security association and infrastructure support, to form a secure collaboration workspace, and share files and application content instantly with minimal human intervention.
Design/methodology/approach
The paper looks at the system implementation and experimentation.
Findings
WShare can automatically establish a peer‐to‐peer network among the participating mobile stations, and provides a transparent shared file repository through which the mobile stations can securely exchange files with simple drag‐and‐drop operations. This file sharing application can also be specialized to support the same file beaming service over wireless LAN as that provided by Palm PDAs over infrared links. On the application sharing front, WShare supports a general remote execution mechanism that can synchronize the state of multiple instances of a standard productivity application, such as PowerPoint, Excel, and Word, across different machines. Finally for sharing generic applications, WShare also integrates virtual network computing with reliable wireless broadcast to provide a user‐interface level sharing mechanism. Performance measurement on the fully operational WShare prototype shows that a collaboration workspace among five mobile nodes can be set up within 3.5 seconds.
Originality/value
This paper proposes a new communication paradigm and presents the design, implementation, and evaluation of a fully‐working prototype.
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Matthias Wählisch and Thomas C. Schmidt
This paper aims to discuss problems, requirements and current trends for deploying group communication in real‐world scenarios from an integrated perspective.
Abstract
Purpose
This paper aims to discuss problems, requirements and current trends for deploying group communication in real‐world scenarios from an integrated perspective.
Design/methodology/approach
The Hybrid Shared Tree is introduced – a new architecture and routing approach to combine network – and subnetwork‐layer multicast services in end‐system domains with transparent, structured overlays on the inter‐domain level.
Findings
The paper finds that The Hybrid Shared Tree solution is highly scalable and robust and offers provider‐oriented features to stimulate deployment.
Originality/value
A straightforward perspective is indicated in the paper for a mobility‐agnostic routing layer for future use.
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Jouni Smed, Timo Kaukoranta and Harri Hakonen
Distributed, real‐time multiplayer computer games (MCGs) are in the vanguard of utilizing the networking possibilities. Although related research has been done in military…
Abstract
Distributed, real‐time multiplayer computer games (MCGs) are in the vanguard of utilizing the networking possibilities. Although related research has been done in military simulations, virtual reality systems, and computer supported cooperative working, the suggested solutions diverge from the problems posed by MCGs. With this in mind, this paper provides a concise overview of four aspects affecting networking in MCGs. First, networking resources (bandwidth, latency, and computational power) set the technical boundaries within which the MCG must operate. Second, distribution concepts encompass communication architectures (peer‐to‐peer, client/server, server‐network), and both data and control architectures (centralized, distributed, replicated). Third, scalability allows the MCG to adapt to the resource changes by parametrization. Finally, security aims at fighting back against cheating and vandalism, which are common in online gaming.
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H. Kabir, Gholamali C. Shoja and Eric G. Manning
Streaming audio/video contents over the Internet requires large network bandwidth and timely delivery of media data. A streaming session is generally long and also needs a large…
Abstract
Streaming audio/video contents over the Internet requires large network bandwidth and timely delivery of media data. A streaming session is generally long and also needs a large I/O bandwidth at the streaming server. A streaming server, however, has limited network and I/O bandwidth. For this reason, a streaming server alone cannot scale a streaming service well. An entire audio/video media file often cannot be cached due to intellectual property right concerns of the content owners, security reasons, and also due to its large size. This makes a streaming service hard to scale using conventional proxy servers. Media file compression using variable‐bit‐rate (VBR) encoding is necessary to get constant quality video playback although it produces traffic bursts. Traffic bursts either waste network bandwidth or cause hiccups in the playback. Large network latency and jitter also cause long start‐up delay and unwanted pauses in the playback, respectively. In this paper, we propose a proxy based constant‐bit‐rate (CBR)‐transmission scheme for VBR‐encoded videos and a scalable streaming scheme that uses a CBRtransmission scheme to stream stored videos over the Internet. Our CBR‐streaming scheme allows a server to transmit a VBRencoded video at a constant bit rate, close to its mean encoding bit rate, and deals with the network latency and jitter issues efficiently in order to provide quick and hiccup free playback without caching an entire media file. Our scalable streaming scheme also allows many clients to share a server stream. We use prefix buffers at the proxy to cache the prefixes of popular videos, to minimize the start‐up delay and to enable near mean bit rate streaming from the server as well as from the proxy. We use smoothing buffers at the proxy not only to eliminate jitter and traffic burst effects but also to enable many clients to share the same server stream. We present simulation results to demonstrate the effectiveness of our streaming scheme.
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