Francesco Mininni’s research while affiliated with Polytechnic University of Turin and other places

We address cooperative caching in mobile ad hoc networks where information is exchanged in a peer-to-peer fashion among the network nodes. Our objective is to devise a fully-distributed caching strategy whereby nodes, independently of each other, decide whether to cache or not some content, and for how long. Each node takes this decision according to its perception of what nearby users may be storing in their caches and with the aim to differentiate its own cache content from the others'. We aptly named such algorithm "Hamlet". The result is the creation of a content diversity within the nodes neighborhood, so that a requesting user likely finds the desired information nearby. We simulate our caching algorithm in an urban scenario, featuring vehicular mobility, as well as in a mall scenario with pedestrians carrying mobile devices. Comparison with other caching schemes under different forwarding strategies confirms that Hamlet succeeds in creating the desired content diversity thus leading to a resource-efficient information access.

In this paper, a new variant of the McEliece cryptosystem, based on quasi-cyclic low-density parity-check (QC-LDPC) codes, is studied. In principle, such codes can substitute Goppa codes, originally used by McEliece; their adoption, however, is subject to cryptanalytic evaluation to ensure sufficient system robustness. The authors conclude that some families of QC-LDPC codes, based on circulant permutation matrices, are inapplicable in this context, due to security issues, whilst other codes, based on the "difference families" approach, can be able to ensure a good level of security against intrusions, even if very large lengths are needed.

Low Density Parity Check codes over Z8, the group of integers modulo 8, are considered. When applied to 8-PSK constellations, they generate geometrically uniform Euclidean space codes: distance profile and word error probability are the same for each transmitted codeword. Some insights on code design, encoding, decoding, and simulated performance are provided.

In this paper, we study a new class of Low Density Parity Check codes, designed for satellite communications, and achieving both high spectral efficiency and large coding gain. Given a constant-envelope 8-PSK constellation, a generic linear binary code does not lead to a geometrically uniform Euclidean-space code. Low Density Parity Check codes over Z_8, the group of integers modulo 8, are considered. When applied to 8-PSK, they generate geometrically uniform Euclidean space codes: distance profile and word error probability are the same for each transmitted codeword. These properties highly simplify both design and analysis. Some insights on code design, encoding, decoding, and simulated performance are provided.