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Full-Text Articles in Computer Engineering

Retransmission Strategies For Moving Networks Over Ricean Fading Channels, Alex Ruiz Lee Dec 2007

Retransmission Strategies For Moving Networks Over Ricean Fading Channels, Alex Ruiz Lee

Theses

The problem of designing retransmission protocols based on Hybrid Automatic Repeat reQuest (HARQ) for moving networks over Ricean fading channels has been considered. The scenario of interest consists of one receiver traveling at a given speed while connected to a wireless network based on OFDM (e.g., WiMax) through several base stations located along the path. Five different retransmission protocols that combine HARQ with handover between adjacent base stations are considered. Their performance in terms of number of retransmissions per packet via numerical simulations, considering both frequency selective and nonselective channels are presented. The results obtained show the relevant advantage ...


Proactive Methods For Measurement Of Available Bandwidth And Link Capacity, Khondaker Musfakus Salehin Dec 2007

Proactive Methods For Measurement Of Available Bandwidth And Link Capacity, Khondaker Musfakus Salehin

Theses

With the continuous expansion of network infrastructure and deployment of applications sensitive to Quality-of-Service, network measurement plays a major role in both network planning and management. Accurate measurement of various network parameters, e.g., available bandwidth, link capacity, delay, packet loss and jitter, provides a positive impact for effective traffic engineering, Quality-of-Service (QoS) routing, optimization of end-to-end transport performance, and link capacity planning. For network measurement, there exists several proactive estimation tools based on either probe-gap model or probe-rate model that estimate path related attributes. Most of these tools that have been implemented can measure tight-link capacity (smallest available bandwidth ...


Using Gis To Optimize The Design And Implementation Of The Rtk Reference Network In Abu Dhabi, Mustafa Abdulla Mohammed Almusawa Dec 2007

Using Gis To Optimize The Design And Implementation Of The Rtk Reference Network In Abu Dhabi, Mustafa Abdulla Mohammed Almusawa

Theses

Several challenging applications and construction works demand real-time measurements for positioning at the centimeter-level accuracy. This positioning accuracy can be obtained by using a Global Positioning System (GPS) roving unit and employing a single reference station (base-station) or through utilizing the service of multiple reference stations forming a Real-Time Kinematics (RTK) Reference Network.

The limitation of the single reference approach is that measurement errors are distance dependent and good accuracy can be only obtained when distances are less than 10 kms. In addition, this method requires a nearby Geodetic Control Point (GCP). Recently, RTK reference networks are widely established in ...