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The number of wireless Internet service users that use wireless LAN or satellite links has increased. The broadband satellite Internet services have especially attracted attention because of its characteristics such as global coverage and robustness. TCP (transmission control protocol) is used by many typical applications over satellite Internet. However, a typical TCP (such as TCP-NewReno) which...
The scheduling and execution for grid application is an important problem in the grid environment. To get the high reliability and efficiency, we propose a runtime reputation based grid resource selection algorithm. According to the accumulated raw score, the runtime reputation degree for a grid resource is quantified as an evaluating score in the runtime of an application. Instead of being dependent...
We study opportunistic scheduling algorithms in a wireless network with a central base station communicating with multiple users on a single shared channel using time division multiple access. We assume the coexistence of both rate guaranteed (RG) users and best effort (BE) users in the system. A RG user asks for a specific transmission rate and the system should provision the exact amount being asked...
In this paper, the performance of IPv4 and IPv6 are compared using Windows Vista and the TCP throughput results are compared with Windows XP. The results indicated that Windows Vista can provide higher bandwidth than XP for both IPv4 and IPv6. Windows vista performs comparatively better on IPv4 than IPv6.
A massively parallel computer involves a large number of routers that are independent of each other. Adaptive routing methods offer high levels of flexibility in packet routing, but their performance is limited due to their locality nature. The Cross-Line method handles quasi-global information of congestion to improve performance. This paper introduces two new ideas of adaptation level and evaluation...
We propose a new extension for index based scheduling rules which adds a global system perspective by estimating how much a job could benefit from an immediate processing. We implement this criterion in the ATC rule and compare the performances of the standard ATC and the extended rule ATCG. It is shown that ATCG performs better than ATC, especially when system loads are high and processing times...
The propagation delay is one of important characteristics of underwater acoustic networks. The article analyzes two instances offered by applying MACAW protocol and ALOHA protocol to the underwater acoustic network separately, and then tables a proposal to counteract the bad influence of the propagation delay by decreasing the number of non-in-effect packets. Based on the proposal, it puts forward...
This paper focuses on the resource scheduling of LTE-Advanced system with carrier aggregation. With different fading characters, the aggregated carriers have different coverage between each other. Consequently, the carrier aggregation causes that the number of carriers which users can be scheduled on is various. The allocation fairness can not be achieved with the original proportional fair (PF) scheduling...
The combined block diagonalization and geometric mean decomposition (BD-GMD) is a preceding scheme that is asymptotically optimal for downlink multi-user multiple-input-multiple-output (MU-MIMO) systems. The number of simultaneously supportable users with BD-GMD is limited by the number of transmitting and receiving antennas. In a downlink MU-MIMO system with a large number of users, the base station...
To improve the performance of IEEE 802.11 wireless LAN, a novel contention aware adaptive contention window scheme is proposed in this paper. Compared with the binary exponential backoff algorithm defined in standard, our scheme can determine the contention window based on the collision status rapidly and the collision probability can be reduced dramatically. The analysis results show that our mechanism...
Access networks based on cooper cables are costly to build and maintain. For this reason, last-mile access networks based on wireless technologies are gaining considerable attention. Among the wireless technologies being employed, the IEEE802.11 is common place. In such scenarios it is important to have well defined mechanisms to better evaluate traffic characteristics and overall system performance...
The distributed coordination function (DCF) is the most widely deployed medium access control (MAC) protocol for IEEE 802.11 WLANs. It is a carrier sense multiple access with collision avoidance (CSMA/CA) scheme which employs a binary exponential backoff (BEB) algorithm to reduce the collision probability. In this paper we propose a novel backoff algorithm, collision-aware backoff mechanism (CABM),...
Linear-time configurations and RAID have garnered great interest from both analysts and theorists in the last several years. Given the current status of pseudorandom models, cyberneticists obviously desire the study of DHCP, which embodies the extensive principles of machine learning. Based on the game-theoretic methodology and lossless algorithm, it is concluded that the discovered scheme can be...
Parallel transport control protocol (TCP) has been used to effectively utilize bandwidth for data intensive applications over high bandwidth-delay product (BDP) networks. On the other hand, it has been argued that, a single based TCP connection with proper modification such as HSTCP can emulate and capture the robustness of parallel TCP and can well replace it. In this work a Comparison between single-based...
Wireless mesh network (WMN) is a promising technology for broadband Internet access due to its low cost, ease of deployment, increased coverage, and robustness. Equipping each mesh router with multiple radios can greatly improve the capacity of WMNs since the radios at each node can simultaneously transmit data on orthogonal channels. Channel assignment is an important problem in multi-radio multi-channel...
In the original study based on the EDCA, the paper puts forward a concept of priority threshold to control traffics in a node. It makes EDCA mechanisms not only have the characteristics of priority, but also have good fairness. Among the nodes, optimized EDCA mechanism uses slot utilization to reflect the current network status, and changes the maximum and minimum contention window in order to improve...
A novel contention aware adjusting mechanism is proposed in this letter. Compared with the Binary Exponential Backoff algorithm defined in standard, our scheme can determine the contention window based on the collision status rapidly and the collision probability can be reduced dramatically; moreover, the dynamical varying timing method can make the node adjust the number of packets sending to MAC...
Optical Burst Switching (OBS) has been proposed to realize the next generation Internet on the Wavelength Division Multiplexing (WDM) network technology. Optical Burst Switching is an ultra high speed switching technology for optical fiber networks but has the data burst contention problem. In this paper, we introduce Virtual Path (VP) concept addressing burst contention resolutions in OBS networks...
This paper analyzes the influence of self-similar traffic on Ethernet based on the On/Off model, which treats the self-similar process as the superposition of tremendous data sources with heavy-tailed distribution. Simulated in several scenarios with different H parameter, the result indicates that self-similar traffic has negative influence on the performance of networks at delay, throughput and...
The paper focuses on implementation of association pattern between the network performances and the general network faults. We use network simulation tool, OPNET, to accomplish network simulations of different network faults and different situations based on VoIP. Network performance parameters such as end-to-end delay, jitter, traffic dropped, queuing delay, link throughout, link utilization are...
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