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Data Packets (data + packet)

Distribution by Scientific Domains

Information Science and Computing	33%

Selected Abstracts

Joint queue control and user scheduling in MIMO broadcast channel under zero-forcing multiplexing

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 12 2009
Feng She
Abstract This paper studies the problem of queue control and user scheduling in multi-antenna broadcast (downlink) systems under zero forcing beamforming transmit strategy. In the system, we assume that the data packet arrives randomly to the buffered transmitter. By taking the broadcast channel as a controlled queueing system, we deduce the property of queue control function that maximizes the weighted system throughput while guarantees the delay fairness among users. We also present a low-complexity user selection algorithm with the consideration of queue state and channel state together. Simulation results show that the joint queue control and user selection policy can achieve considerable fairness and stability among users. Copyright © 2009 John Wiley & Sons, Ltd. [source]

AODV-RIP: improved security in mobile ad hoc networks through route investigation procedure

CONCURRENCY AND COMPUTATION: PRACTICE & EXPERIENCE, Issue 7 2010
Byung-Seok Kang
Abstract Most routing protocols in mobile ad hoc networks (MANETs) place an emphasis on finding paths in dynamic networks without considering security. As a result, there are a number of attacks that can be used to manipulate the routing in MANET. A malicious node that sends a modified control message to an intermediate node can disturb the network using a control message. To solve this problem, we introduce AODV protocol with route investigation procedure (AODV-RIP). It uses two additional control messages to defeat security attacks that can occur in AODV routing protocol. When an intermediate node that is on the path between the source node and the destination node receives a control message, it sends a Rroute Investigation Request (IREQ) message to the destination node in order to check the reliability of the control message. According to the existence of Route Investigation Reply (IREP), the intermediate node decides whether it transmits the control message to the source node or not. Consequently, the intermediate node that receives the control message confirms that it is using two additive control messages: IREQ and IREP. Through this investigation procedure, the source node can obtain a reliable path for transmitting data packets to an intentional destination node. The simulation results show an improvement in the packet delivery ratio and end-to-end delay at the expense of a moderate increase of the control message overhead compared with the current routing protocols. Copyright © 2009 John Wiley & Sons, Ltd. [source]

QOS and call admission control of multimedia traffic in a PCS network

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 6 2004
Duan-Shin Lee
Abstract In this paper we study the quality of service of integrated voice and data services in a wireless network. The voice traffic is transmitted in circuit-switched mode and data traffic is transmitted in packet-switched mode. Voice traffic has high transmission priority and data packets are transmitted only when there are available channels not used by the voice traffic. Otherwise, the data packets wait in a data buffer. We consider two schemes to reduce the forced termination probability for the handoff voice calls. The two schemes are the reserved channel scheme and the queueing priority scheme. We apply a fluid analysis to study the performance of the data buffer under the two handoff schemes and the basic system in which there is no arrangement to reduce the forced termination probability of handoff calls. From this analysis, we derive admission controls for voice traffic as well as for data traffic. This analysis also enables us to conclude that the reserved channel scheme not only is more effective in reducing the forced termination probability of handoff calls, it is also more effective in providing the QOS guarantee for the data traffic. Another contribution of this paper is to develop a perturbation analysis to solve the fluid models efficiently and quickly. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Split agent-based routing in interconnected networks

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 4 2004
Constandinos X. Mavromoustakis
Abstract Adaptive behaviour of swarm-based agents (BT Technol. J. 1994; 12:104,113; AAMAS Conference '02, Melbourne, Australia, Month 1,2, 2002; Softcomput. J. 2001; 5(4):313,317.) is being studied in this paper with respect to network throughput for a certain amount of data traffic. Algorithmically complex problems like routing data packets in a network need to be faced with a dynamically adaptive approach such as agent-based scheme. Particularly in interconnected networks where multiple networks are participating in order to figure a large-scale network with different QoS levels and heterogeneity in the service of delay sensitive packets, routing algorithm must adopt in frequent network changes to anticipate such situations. Split agent-based routing technique (SART) is a variant of swarm-based routing (Adapt. Behav. 1997; 5:169,207; Proceedings of 2003 International Symposium on Performance Evaluation of Computer and Telecommunication Systems,SPECTS, Montreal, Canada, July 20,24, 2003; 240,247.) where agents are split after their departure to the next node on a hop-by-hop basis. Packets that are delay sensitive are marked as prioritized which agents recognize-as being a part of a packet- and try to influence the two-way routing tables. Thorough examination is made, for the performance of the proposed algorithm in the network and the QoS offered, taking into account a number of metrics. It is shown that the split agent routing scheme applied to interconnected networks offers a decentralized control in the network and an efficient way to increase overall performance and packet control reducing at the same time the packet loss concept. Copyright © 2004 John Wiley & Sons, Ltd. [source]

Analysis of resequencing in downloads

INTERNATIONAL JOURNAL OF COMMUNICATION SYSTEMS, Issue 8 2003
Yoav Nebat
Abstract Recent studies indicate that out-of-order arrival of data packets during downloads of resources is not pathological network behaviour (ACM/IEEE Trans. Networking 1999; 7(6):789). Though this situation is most intuitive when packets of the same resource arrive in parallel from several sources, it turns out that this phenomenon may also occur in the single source scenario. Knowledge regarding the expected reordering needed is important both for being able to decide on the size of the resequencing buffer needed, and to estimate the burstiness in arrival of data to the application. In this study we present a method to calculate the resequencing buffer occupancy probabilities for the single source scenario, and a study of the resequencing buffer occupancy for the two source scenario, where arrival from each of the sources is in order. Copyright © 2003 John Wiley & Sons, Ltd. [source]

AAA architecture for mobile IPv6 based on WLAN

INTERNATIONAL JOURNAL OF NETWORK MANAGEMENT, Issue 5 2004
R. C. Wang
Mobility support for Internet devices is quite important for consumer electronics. The number of the hand-held devices is growing quickly. However, there are not enough IP addresses for the number of the rapidly growing devices in the All-IP generation. Internet Protocol version 6 (IPv6) was therefore adopted to solve these problems. Our purposed structure is based on IEEE 802.11. However, IEEE 802.11 has a serious security drawback. Further, from the Internet Service Providers' point of view, accounting is a potential problem. A mechanism combining Mobile IPv6 and AAA based on IEEE 802.11 to overcome these problems is essential. Both Internet Protocol version 4 (IPv4) and IPv6 support IP security (IPsec) when data packets are exchanged across the IP network. IPsec operates at the IP layer. It can support system authentication and authorization, However, it lacks a system accounting function. Therefore ISPs cannot establish correct billing for their services. This is the reason why we chose to combine the wireless network and AAA functions. In this paper, the AAA mechanism is used to protect security, with the architecture having authentication, authorization, and accounting functions. We will discuss the benefits of AAA and state the reason why we choose to combine AAA with the mobility architecture.,Copyright © 2004 John Wiley & Sons, Ltd. [source]