Antonio Vilei

A new UPnP architecture for distributed video voice over IP

In this paper we present a novel approach to video telephony where we are able to exploit the benefits of the Universal Plug and Play (UPnP) protocol: self-configuration, discovery and control of available devices connected to the network. At the time being, UPnP does not deal with Video Voice over IP (VVoIP) applications. Integrating a signaling protocol like the Session Initiation Protocol (SIP) with UPnP allows interaction between the videophone and other UPnP compliant devices, like a TV set or a media server. This interaction, for example, makes it feasible to display the callers image on the television screen, thus allowing the user to relax on the sofa and naturally converse. Another interesting scenario is the one where the user sends to the conversation partner a set of still pictures or short video clips acquired from a UPnP media server already available in the home premises. An advantage of this distributed approach is its cost effectiveness, since it allows to reuse existing UPnP devices also in the context of video telephony. The integration between SIP and UPnP has been achieved introducing a new UPnP device, the VVoIP device, which is a SIP User Agent able to interoperate with standard UPnP MediaServers and Medi-aRenderers.

Implementation of the EXI Schema on Wireless Sensor Nodes Using Contiki

The current trend in Wireless Sensor Networks (WSN) is to use the Internet Protocol (IP) and open standards to achieve native connectivity between smart objects and the Internet, contributing to consolidate the Internet of Things (IoT). Emerging standards such as 6LoWPAN/IPv6 and CoRE/CoAP will play a very important role in a Restful Web of Things, where each node has its own IPv6 address and is able to provide information and control about itself. Data exchanging in Machine To Machine (M2M) applications and communication with Web services require the use of structured data. XML is a possible solution, but its verbosity is not suitable for a WSN (e.g. based on IEEE 802.15.4) characterized by limited packet size. This paper investigates the benefits of Efficient XML Interchange (EXI) in a real scenario, considering sensor nodes running on the Contiki RTOS. For this purpose, the authors have implemented an extremely lightweight version of EXI for Contiki running on application boards with just 8 Kbyte RAM memory.

Unbalanced multiple description with variable frame rate

This paper describes a technique based on Unbalanced Multiple Description Coding to improve the robustness of video transmission. The proposed system relies on two descriptions, HR (High-Resolution) and LR (Low-Resolution) where LR is primarily used as redundancy. HR and LR are produced by using different encoding parameters. HR has constant frame rate and is encoded in such a way to optimize video quality. LR, on the other hand, uses only intra frames and its frame rate is dynamically adapted to the amount of motion. Using only intra frames in LR allows fast encoding/decoding time and provides resilience to bursts of packet losses. This technique produces acceptable quality even if redundancy percentage is less than packet loss rate. Therefore this approach is suitable for multicast video distribution over wireless links where estimating packet loss can be a difficult task because different receivers experience different loss patterns.

Architecture of QOSMIC - A QoS Manager for Internet Connections

RSVP is an Internet protocol designed to reserve network resources. Availability of optimized free implementations of RSVP daemon and the development of extensions designed to improve RSVPs behaviour have increased the attention towards the protocol. Though RSVP has been designed to fulfill QoS needs of multimedia applications, development of compliant applications is slowed by complexity of logic behind the access to QoS. This paper describes the current problems related to the deployment of RSVP into multimedia applications and the QOSMIC architecture in support to multimedia applications that tries to solve these problems. The QOSMIC elements allow a user to reserve resources without requiring the update of multimedia applications neither on the client side nor on the server one, allow a receiving user to require RSVP Path messages needed to start reservations and allow a centralized management of QoS. A test implementation of QOSMIC is also briefly described.