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Last Update, January 2, 2014
Dr. Giovanni Giambene Web Page
Dr. Giovanni Giambene Web Page
Copyright 2011 by Giovanni Giambene    All Rights reserved
Recent Research Activity
Giambene is active in the following main research areas on wireless communications and networking:

- MAC access optimization in IEEE 802.16d/e/m
- Hybrid networking (terrestrial wireless and satellite segment)
- Air interface cross-layer design
- Transport layer performance optimization in GEO satellite networks
- Application of queuing theory for performance evaluation.

Details on selected topics are provided below.

WiMAX Access Analysis (MAC)
WiMAX is a broadband Internet access technology that allows addressing the last mile problem in many situations where wired solutions are not convenient. Focusing on the point-to- multipoint mode, where the base station decides about resource allocations in both uplink and downlink, this activity has focused on an accurate analysis for the WiMAX contention-based access. This study is carried out in non-saturated conditions that allow considering a queuing model to describe the mean packet delay. The goodness of the theoretical approach has been proved by comparisons with simulation results.

Hybrid Networks
GEO satellite communication systems are an efficient solution for broadband Internet provision on high-speed trains, but some work is still needed to allow a seamless service. This activity deals with improving the TCP performance using vertical handovers (based on MIH) from the satellite to a terrestrial wireless segment (hybrid network) and vice-versa to cover tunnels. Simulation results show that TCP goodput behavior and convergence time can be improved by means of suitable accelerated TCP versions or with cross-layer methods.

Performance Evaluation
Broadband wireless systems are becoming very popular today and several technologies are available. This study proposes a general analytical framework that is suitable for the performance evaluation of downlink queues in current packet-switched broadband wireless systems, like WiFi, WiMAX, LTE, and DVB-S2. The downlink queue analysis has been carried out considering that 'b' resources can be scheduled on a frame basis and that the messages have a variable size depending on different lengths and/or the use of different modulation and coding combinations.