The Design and Implementation of a Hybrid Classical-Quantum Annealing Polar Decoder

We present the Hybrid Polar Decoder (HyPD), a hybrid of classical CMOS and quantum annealing (QA) computational structures for decoding Polar error correction codes, which are becoming widespread in today's 5G and tomorrow's 6G networks. HyPD considers CMOS for the Polar code's binary tree traversal, and QA for executing a Quantum Polar Decoder (QPD)-a novel QA-based maximum likelihood submodule. Our QPD design efficiently transforms a Polar decoder into a quadratic polynomial optimization form amenable to the QA's optimization process. We experimentally evaluate HyPD on a state-of-the-art QA device with 5,627 qubits, for Polar codes of block length 1,024 bits, in Rayleigh fading channels. Our results show that HyPD outperforms successive cancellation list decoders of list size eight by half an order of bit error rate magnitude at 1 dB SNR. Further experimental studies address QA compute time at various code rates, and with increased QA qubit numbers.