Demand Private Coded Caching: The Two-File Case
Qinyi Lu, Nan Liu, Wei Kang · 2024
We investigate the demand private coded caching problem, which is an$(N,\ K)$coded caching problem with$N$files,$K$users, each equipped with a cache of size$M$, and an additional privacy constraint on user demands. We first present a new virtual-user-based achievable scheme for arbitrary number of users and files. Then, for the case of 2 files and arbitrary number of users, we derive some new converse bounds. As a result, we obtain the exact memory-rate tradeoff of the demand private coded caching problem for 2 files and 3 users. As for the case of 2 files and arbitrary number of users, the exact memoryrate tradeoff is characterized for$M\in[0,\ \frac{2}{K}]\cup[\frac{2(K-1)}{K+1},\ 2]$.