@article{12738,
  author = {Felix Leditzky and Mohammad Alhejji and Joshua Levin and Graeme Smith},
  title = {Playing games with multiple access channels},
  abstract = {<p>Communication networks have multiple users, each sending and receiving messages. A multiple access channel (MAC) models multiple senders transmitting to a single receiver, such as the uplink from many mobile phones to a single base station. The optimal performance of a MAC is quantified by a capacity region of simultaneously achievable communication rates. We study the two-sender classical MAC, the simplest and best-understood network, and find a surprising richness in both a classical and quantum context. First, we find that quantum entanglement shared between senders can substantially boost the capacity of a classical MAC. Second, we find that optimal performance of a MAC with bounded-size inputs may require unbounded amounts of entanglement. Third, determining whether a perfect communication rate is achievable using finite-dimensional entanglement is undecidable. Finally, we show that evaluating the capacity region of a two-sender classical MAC is in fact NP-hard.</p>
},
  year = {2020},
  journal = {Nature Communications},
  volume = {11},
  pages = {1497},
  month = {2020-03},
  url = {https://www.nature.com/articles/s41467-020-15240-w},
  doi = {10.1038/s41467-020-15240-w},
}