M3COM · Multidimentional Modulation for Multimedia Communications

Multidimentional Modulation for Multimedia Communications

The general scientific objectives of this project was to improve the performance of transceivers that exploit multi-dimensional (MD) communication channels and provide tools to match their varying protection capability with unequal error protection (UEP) requirement of the video encoders. The specific scientific objectives of this project were the following: - Design and analysis of multi-dimensional (MD) coded modulation schemes appropriate for channels explicitly offering multiple transmission dimensions, that is, hybrid automatic request (HARQ) and relay communications. - Design and analysis of coded hierarchical modulation (HM) schemes for unequal error protection in the 1-D and M-D transmissions. In this work the two specific scientific objectives were addressed and the effort of the research team was roughly equally divided into these two tasks. The research on the HARQ transmission focused on the analysis and optimisation f the HARQ transmission with variable rate operation in rapidly varying channels. These ideas also open promising venues for the further research, particularly on the relay-based communications. This work has produced the tangible results, yielding publications. As for the HM transmission we worked on its two aspects. The first one was related to the code-modulation for non-uniform (e.g. HM) constellations. Namely we exploited the idea of non-uniform constellation being the very basis of the HM, to couple it with UEP introduced by the channel encoder. Another aspect we worked on with a MSc student of Supelec and a post-doctoral fellow from INRS, Canada consisted in an information-theoretic analysis of hierarchical modulation. Namely, we worked on the extension of the conventional theory of superposition coding from continuous signalling to discrete signal sets. The aim was to validate the basic idea of HM, which adopts in an ad-hoc manner the general principles of superposition coding. This work produced two internal reports that will form a basis for the forthcoming publication. The main structuring outcome of the fellowship was establishing of the solid, confidence-based collaborative links between LSS (CNRS) and INRS, Canada. Our objective was to establish an international research group involving also other partners (such as Chalmers University in Sweden, Orange France Telecom in France, and McGill University in Canada) to increase the international visibility of the collaborating institutions. We opted for a three-step approach to build such collaboration. In the first step, we put to work our complementary expertise to prove that the idea of joint work is valid and produces tangible results as measured by the co-supervision of students and by the joint publications. In the second step we applied for the funding to increase the intensity of the research in collaboration, and to involve more students into the group. This was done in Canada where we were successful in obtaining two research grants from the Quebec government. The grant application with a strong component of international mobility (with INRS, Canada, in particular) was also filled in Sweden. Currently we are working on the establishment of the so-called Associated International Laboratory (LIA) of CNRS that will fund the research activities of French researchers in Canada. The main objective of the funding is to allow for the exchange of the students between the involved institutions that will lead to a stronger and more focused collaborative program.

Data: CORDIS, © European Union