Benjamin Drozdenko | Searcharxiv

arXiv2026

Finite Key Underwater Quantum Key Distribution: Performance Analysis and Improvements

Quantum key distribution (QKD) allows for the establishment of a secret key between two parties, secure against computationally unbounded adversaries. Most experimental and theoretical research in this area, investigates the performance of QKD over fiber or free space channels. A growing body of work, however, has begun to investigate its performance in underwater scenarios. Here, we consider the realistic finite key scenario, and evaluate the simulated performance of two different decoy state protocols. We show that there are certain underwater channels where "simpler" QKD protocols outperform more complex ones. Finally, we also investigate methods to improve QKD performance underwater, specifically looking at classical advantage distillation, which we show can greatly improve the maximal distance supported by QKD underwater.

quant-ph↗

arXiv2016

High-Level System Design of IEEE 802.11b Standard-Compliant Link Layer for MATLAB-Based SDR

Software defined radio (SDR) allows unprecedented levels of flexibility by transitioning the radio communication system from a rigid hardware platform to a more user-controlled software paradigm. However, it can still be time consuming to design and implement such SDRs as they typically require thorough knowledge of the operating environment and a careful tuning of the program. In this work, our contribution is the design of a bidirectional transceiver that runs on the commonly used USRP platform and implemented in MATLAB using standard tools like MATLAB Coder and MEX to speed up the processing steps. We outline strategies on how to create a state-action based design, wherein the same node switches between transmitter and receiver functions. Our design allows optimal selection of the parameters towards meeting the timing requirements set forth by various processing blocks associated with a DBPSK physical layer and CSMA/CA/ACK MAC layer so that all operations remain functionally compliant with the IEEE 802.11b standard for the 1 Mbps specification. The code base of the system is enabled through the Communications System Toolbox and incorporates channel sensing and exponential random back-off for contention resolution. The current work provides an experimental testbed that enables creation of new MAC protocols starting from the fundamental IEEE 802.11b standard. Our design approach guarantees consistent performance of the bi-directional link, and the three node experimental results demonstrate the robustness of the system in mitigating packet collisions and enforcing fairness among nodes, making it a feasible framework in higher layer protocol design.

cs.NI↗