Computation-aided classical-quantum multiple access to boost network communication speeds

Abstract

A multiple access channel (MAC) consists of multiple senders simultaneously transmitting their messages to a single receiver. For the classical-quantum case (cq-MAC), achievable rates are known assuming that all the messages are decoded, a common assumption in quantum network design. However, such a conventional design approach ignores the global network structure, i.e., the network topology. When a cq-MAC is given as a part of quantum network communication, this work shows that computation properties can be used to boost communication speeds with code design dependently on the network topology. We quantify achievable quantum communication rates of codes with computation property for a two-sender cq-MAC. When the two-sender cq-MAC is a boson coherent channel with binary discrete modulation, we show that it achieves the maximum possible communication rate (the single-user capacity), which cannot be achieved with conventional design. Further, such a rate can be achieved by different detection methods: quantum (with and without quantum memory), on-off photon counting and homodyne (each at different photon power). Finally, we describe two practical applications, one of which cryptographic.

The Quantum Multiple-Access Channel with Cribbing Encoders

“…entanglement between receivers does not increase achievable rates. Related settings of the quantum MAC involve transmission of quantum information [22,23], error exponents [24], non-additivity effects [25], security [26][27][28][29], and computation codes [30]. The sixth generation of cellular network (6G) is expected to achieve gains in terms of latency, resilience, computation power, and trustworthiness in future communication systems, such as the tactile internet [31], which not only transfer data but also control physical and virtual objects, by using quantum resources [32].…”