Final report on the evaluation of RRM/CRRM algorithms

Deliverable public del projecte EVERESTThis deliverable provides a definition and a complete evaluation of the RRM/CRRM algorithms selected in D11 and D15, and evolved and refined on an iterative process. The evaluation will be carried out by means of simulations using the simulators provided at D07, and D14.Preprin

Association Control in Wireless Mesh Networks

Ph.DDOCTOR OF PHILOSOPH

SIP-based proactive and adaptive mobility management framework for heterogeneous networks

Abstract In this paper, we present and evaluate the performance of a mobility management system called the Proactive and Adaptive Handover (PAHO) system. PAHO is an application-level approach that uses SIP to manage client-initiated connection handoff across heterogeneous networks based on the IEEE 802.21 framework with designated user/configuration policy. Unlike conventional systems which make sub-optimal decision when managing connection handoff due to limited awareness of the relevant context for the application/service being delivered, PAHO defines proper interface to interact with the application as to determine when and to where the handoff and/or codec switching should take place in the event of network performance degradation. The results showed that using the PAHO approach on an audio/video conferencing session helps reducing the overall handover delay from 10.766 s (on non-PAHO system) down to at least 288 ms, and slowing down the degradation of MOS value throughout the entire experiment in the event of signal degradation as well as network congestion. It is also shown that load balancing among the access points (AP) could be achieved with an improved Information Server (IS). r 2007 Elsevier Ltd. All rights reserved

A Self-Management Approach to Configuring Wireless Infrastructure Networks

Wireless infrastructure networks provide high-speed wireless connectivity over a small geographical area. The rapid proliferation of such networks makes their management not only more important but also more difficult. Denser network deployments lead to increased wireless contention and greater opportunities for RF interference, thereby decreasing performance. In the past, wireless site surveys and simplified wireless propagation models have been used to design and configure wireless systems. However, these techniques have been largely unsuccessful due to the dynamic nature of the wireless medium. More recently, there has been work on dynamically configurable systems that can adapt to changes in the surrounding environment. These systems improve on previous approaches but are still not adequate as their solutions make unrealistic assumptions about the operating environment. Nevertheless, even with these simplified models, the network design and configuration problems are inherently complex and require tradeoffs among competing requirements. In this thesis, we study a self-management system that can adjust system parameters dynamically. We present a system that does not impose any restrictions on the operating environment, is incrementally deployable, and also backwards compatible. In doing so, we propose, (i) framework for modeling system performance based on utility functions, (ii) novel approach to measuring the utility of a given set of configuration parameters, and (iii) optimization techniques for generating and refining system configurations to maximize utility. Although our utility-function framework is able to capture a variety of optimization metrics, in this study, we focus specifically on maximizing network throughput and minimizing inter-cell interference. Moreover, although many different techniques can be used for optimizing system performance, we focus only on transmit-power control and channel assignment. We evaluate our proposed architecture in simulation and show that our solution is not only feasible, but also provides significant improvements over existing approaches

Quality-Oriented Mobility Management for Multimedia Content Delivery to Mobile Users

The heterogeneous wireless networking environment determined by the latest developments in wireless access technologies promises a high level of communication resources for mobile computational devices. Although the communication resources provided, especially referring to bandwidth, enable multimedia streaming to mobile users, maintaining a high user perceived quality is still a challenging task. The main factors which affect quality in multimedia streaming over wireless networks are mainly the error-prone nature of the wireless channels and the user mobility. These factors determine a high level of dynamics of wireless communication resources, namely variations in throughput and packet loss as well as network availability and delays in delivering the data packets. Under these conditions maintaining a high level of quality, as perceived by the user, requires a quality oriented mobility management scheme. Consequently we propose the Smooth Adaptive Soft-Handover Algorithm, a novel quality oriented handover management scheme which unlike other similar solutions, smoothly transfer the data traffic from one network to another using multiple simultaneous connections. To estimate the capacity of each connection the novel Quality of Multimedia Streaming (QMS) metric is proposed. The QMS metric aims at offering maximum flexibility and efficiency allowing the applications to fine tune the behavior of the handover algorithm. The current simulation-based performance evaluation clearly shows the better performance of the proposed Smooth Adaptive Soft-Handover Algorithm as compared with other handover solutions. The evaluation was performed in various scenarios including multiple mobile hosts performing handover simultaneously, wireless networks with variable overlapping areas, and various network congestion levels