The Capacity of Private Information Retrieval from Decentralized Uncoded Caching Databases

Understand

We consider the private information retrieval (PIR) problem from decentralized uncoded caching databases.

• There are two phases in our problem setting, a caching phase, and a retrieval phase.
• In the caching phase, a data center containing all the $K$ files, where each file is of size $L$ bits, and several databases with storage size constraint $\mu K L$ bits exist in the system.
• Each database independently chooses $\mu K L$ bits out of the total $KL$ bits from the data center to cache through the same probability distribution in a decentralized manner.