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In this paper we present several different approaches to a routing calculation in an ad-hoc network. By using different weights for each link, each algorithm generates a different path, with its own number of hops and maximum throughput. Tests were performed in our own IEEE 802.11e simulator and the results allow to conclude that the cross-layer approach has advantages over the traditional one. In...
This paper seeks to explore the integration of spectrum and network resource management functionalities to the benefit of achieving higher performance and capacity gains in an IMT-A scenario. In particular, we investigate the allocation of users over two frequency bands (i.e., 2 GHz and 5 GHz ones) for a single operator scenario. The same type of RAT is considered for both frequency bands. It is assumed...
This paper investigates and proposes a framework for the efficient integration of functionalities for dynamic spectrum use (e.g., spectrum aggregation) and cooperative radio resource management (RRM) in the scope of IMT-Advanced (IMT-A) candidate systems. The envisaged technical solution is based on a joint centralized and distributed approach for both intra-and inter-operator scenarios. Spectrum...
Networks of the future envisage a network-of-wireless-networks that provide the end user the means to connect to the best available network at anytime and at any place. However, equally challenging for the operators is to provide these services at low cost in an era where spectral resources are a premium. This paper investigates cooperation between networks based radio access technology (RAT) selection...
Optimization of IEEE 802.11e MAC protocol performance is addressed by modifying several parameters left open in the standard, like block size and acknowledgement policies in order to improve the channel efficiency. The use of small block sizes leads to a high overhead caused by the negotiation on the other hand, the use of large block sizes causes long delays, which can affect negatively real-time...
Smart Clothing is a project that combines research in textiles materials and wireless sensor and actuator networks in the context of human body monitoring with statistical methods for the data analysis and treatment. This project aims mainly to aid in the monitoring of the foetal movement in the last four weeks of pregnancy. Besides the integration of sensors in the garment there will be needed a...
Optimization of IEEE 802.11e MAC protocol performance is done by modifying several parameters left open in the standard, like buffer size and acknowledgement policies. By using the developed event-driven simulator, results were extracted with single and multi-service. With only a single service, higher values for the goodput are obtained for video and background (BK) traffics in comparison with the...
This paper addresses aspects of design of WiMAX wireless networks to establish a point-to-point, PTP, link with Alvarion BreezeNET B equipment, from the Health Sciences Faculty of University of Beira Interior to Hospital Sousa Martins (Guarda), and also presents a field trial with pre-WiMAX PTP equipment. The design of the link with relays had into consideration the carrier to noise ratio, C/N, and...
A multi-service traffic model is briefly presented, and its validation is achieved by using event-based simulation results which consider the burstiness of traffic. A simulator was produced to extract conclusions about blocking and handover failure probabilities in a multi-service bursty traffic context. Simulations, were performed for different cases, from single- to multi-service situations, and...
An overview of all-IP enhanced Universal Mobile Telecommunication System, E-UMTS, service needs in the business city centre, BCC, scenario is first presented. Then, E-UMTS traffic generation and activity models are described and characterised. System level simulations are carried out and the enhanced performance is demonstrated based in a single quality parameter, which simultaneously accounts for...
After 3G mobile and wireless systems take-up, the research community is now directing its interest towards unified ways of looking at system design, optimization, and quality of service (QoS) issues to satisfy the requirements of next generation multi-service mobile and wireless IP-based networks. Their implementation requires the development of IP QoS architecture and mechanisms encompassing the...
It is shown that enhanced UMTS is an affordable solution for providing the required network quality and to reduce infrastructure investments in offices scenarios. System capacity results are obtained by using a system level simulator which considers traffic characterisation parameters and services usage in detail, among other. Results for the most profitable cell radius are obtained via an optimisation...
A multi-service traffic model is proposed, and its validation is achieved by using event-based simulation results. In the single-service case, theoretical and experimental results for ON-OFF blocking probability are close to each other, and there is an almost perfect concordance between theoretical and simulation values when the average sojourn time in cells is equal to the average holding time. In...
In this paper Enhanced UMTS offices scenarios and classes of services up to wideband are taken into account. A model is proposed for optimising Enhanced UMTS based in costs and revenues. A system level simulator is used to obtain the blocking probability, and other QoS measures, e.g., handover failure probability and delay. Using these results, one obtains the system capacity, i.e., the supported...
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