Multiple access with finite payloads and many users.
Event details
| Date | 22.10.2019 |
| Hour | 16:15 › 17:15 |
| Speaker | Prof. Yury Polyanskiy, MIT (currently visiting IPG in EPFL) |
| Location | |
| Category | Conferences - Seminars |
One of the next frontiers in communication technology is to re-think methods of sharing spectrum among wireless transmitters. In this talk, I will discuss recent results on characterizing the fundamental tradeoff between the density of users (ratio of active users and the number of degrees of freedom available per frame) and the minimal required energy-per-bit (Eb/N0). In the regime of interest for the Internet-of-Things, the payload of each user is about 100 data bits. This is too small for the asymptotic Shannon theory to provide any guidance and thus we needed to develop new tools for analysis. A surprising discovery is existence of coded-access schemes that are able to almost perfectly reject the multi-user interference, so that increasing the density of users (without increasing space-time-frequency resources) does not lead to any deterioration of service. Practically important is that known MAC architectures are not capable of attaining this effect. A similar analysis and effects arise in the problem of (unsourced) random-access over the AWGN channel, which we will discuss as well.
Practical information
- Informed public
- Free
Organizer
- IPG Seminars
Contact
- O. Lévêque Prof. Polyanskiy is hosted by LTHC (R. Urbanke)