Entanglement-Assisted Bosonic MAC: Achievable Rates and Covert Communication

TL;DR

This paper analyzes the capacity and covert communication limits of an entanglement-assisted bosonic multiple access channel, revealing how entanglement and high-order PSK modulation enhance achievable rates and covert throughput.

Contribution

It derives a closed-form achievable rate region for the EA bosonic MAC and characterizes the covert throughput scaling, demonstrating advantages of entanglement assistance in multi-user covert communication.

Findings

Capacity region collapses into a rectangle in the low-photon regime.

Achievable covert throughput scales as O(√n log n), surpassing the square-root law.

Joint covertness constraint causes a linear trade-off between senders' throughput.

Abstract

We consider the problem of covert communication over the entanglement-assisted (EA) bosonic multiple access channel (MAC). We derive a closed-form achievable rate region for the general EA bosonic MAC using high-order phase-shift keying (PSK) modulation. Specifically, we demonstrate that in the low-photon regime the capacity region collapses into a rectangle, asymptotically matching the point-to-point capacity as multi-user interference vanishes. We also characterize an achievable covert throughput region, showing that entanglement assistance enables an aggregate throughput scaling of \(O(\sqrt{n} \log n)\) covert bits with the block length $n$ for both senders, surpassing the square-root law as in the point-to-point case. Our analysis reveals that the joint covertness constraint imposes a linear trade-off between the senders throughput.