Marcos F. Caetano

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The main contribution of this work is to propose a distributed and collaborative cache solution in which the decisions to cache objects are performed in a collaborative way. In our solution, objects are classified in private and shared objects. Private objects are managed as in an individual cache system whereas the management of shared objects are(More)
This work presents a packet aggregation mechanism tailored for real time applications over wireless network environments. In the core of the proposed mechanism lies an elaborated packet holding time estimation. This estimation is used to allow for packet aggregation along a multihop path. The proposed mechanism was evaluated and compared with another(More)
Estimating the throughput of an WiFi connection can be quite complex, even when considering simplified scenarios. Indeed, the varying number of parameters specified in the standards makes it hard to understand their impact in terms of delay and throughput. The main contribution of this work is to present a simple scheme to compute the exact maximum(More)
Estimating the throughput of a WiFi connection can be quite complex, even when considering simple scenarios. Indeed, the varying number of parameters specified in the standards makes it hard to understand their impact in terms of delay and throughput. The main contribution of this work is to present a scheme to compute the exact maximum throughput for an(More)
Wireless networking enhanced with multiple transmitting channels has been considered to improve the utilization of the electromagnetic spectrum and to provide ways to accommodation the growing demand for connectivity. In this scenario, the use of a common control channel to coordinate the stations and networking resources is usually employed. This work(More)
The current spectrum allocation model aims to avoid interferences in licensed spectrum communications without further concerns regarding spectrum usage. Because the radio spectrum is a finite resource, several approaches have been presented in order to improve the effectiveness of its utilization. The main contribution of this work is to present an(More)
Contention-based protocols are commonly used for providing channel access to the nodes wishing to communicate. The Binary Exponential Back off (BEB) is a well-known contention protocol implemented by the IEEE 802.11 standard. Despite its widespread use, Medium Access Control (MAC) protocols employing BEB struggle to concede channel access when the number of(More)
The use of wireless technology to communicate has spread to a variety of devices. Traditional solutions based on the well known IEEE 802.11 struggle to cope with a large number of contending nodes. The need to improve throughput and meet QoS requirements has driven the quest for more elaborated channel access mechanisms. The main contribution of this work(More)
Reading the contents of Web page with a small-screen device, such as a PDA or cell-phone, is still far from being a pleasant experience. Owing to the device limitations, current mobile browsers cannot handle all HTML tags, such as tables, for instance. Thus, most mobile browsers provide a linearized version of the source HTML page, leading to a large amount(More)