In this paper we present a novel framework for ns2 to facilitate the simulation and, in general, the design of beyond 3G networks. The set of libraries we wrote for this purpose is called <i>Multi InteRfAce Cross Layer Extension</i> for ns2 (MIRACLE). They enhance the functionalities offered by the Network Simulator ns2 by providing an efficient and… (More)
The physical rate adaptation in 802.11 is a deeply investigated , though still open issue. Since 802.11 uses the random access Distributed Coordination Function (DCF) mechanism to access the medium, collisions can occur when two or more stations want to transmit data simultaneously. The challenge of rate adaptation schemes is to adapt the physical… (More)
The design of WLANs was meant to extend Ethernet LANs in the most transparent way, but no particular mechanism was deployed in order to support real-time applications natively. At present VoIP calls are becoming customary, and IEEE802.11 WLANs must face the provision of guaranteed quality of service. In practice, QoS should be provided somehow a posteriori… (More)
—Rate Adaptation for 802.11 has been deeply investigated in the past, but the problem of achieving optimal Rate Adaptation with respect not only to channel-related errors but also to contention-related issues (i.e., collisions and variations in medium access times) is still unsolved. In this paper we address this issue by proposing 1) a practical definition… (More)
In recent years, network simulation has become a very difficult task due to the proliferation and integration of wireless technologies. In this paper, we discuss the new challenges that have arisen regarding the simulation of the wireless channel and the PHY, MAC and Routing layers, argumenting why currently available network simulation tools such as ns2… (More)
—In this paper we present APOS, a method for dynamically adapting the parameters of IEEE 802.11g to the estimated system state, with the aim of enhancing the quality of a voice communication between a mobile station and a remote peer node. The system state is estimated based on a number of counters that are collected by the MAC layer of the mobile station,… (More)
Besides turbo codes, low-density parity-check (LDPC) codes form another class of Shannon limit-approaching codes. Their large coding gains are mostly due to the decoding algorithm, termed message passing algorithm (MPA) or sum-product algorithm (SPA).