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This paper proposes a novel two-way free-space quantum key distribution (QKD) protocol, which can be implemented using standard free-space optical (FSO) systems with subcarrier intensity-modulation (SIM) binary phase-shift-keying (BPSK) and direct-detection (DD) receiver. Different eavesdropping threats, including unauthorized receiver, beam-splitting, and intercept-resend attacks, are considered...
Realistic public wireless channels and quantum key distribution (QKD) systems are amalgamated. Explicitly, we conceive network coding aided cooperative QKD over free space optical systems for improving the bit error ratio and either the key rate or the reliable operational distance. Our system has provided a 55% key rate improvement against the state-of-the-art benchmarker.
This paper presents a comprehensive cross-layer analysis framework on the performance of transmission control protocol (TCP) over free-space optical (FSO) links, which employ the automatic repeat request (ARQ) and adaptive modulation and coding (AMC) schemes. From the framework, we quantify the impacts of different parameters/settings of ARQ, AMC and FSO links on TCP throughput performance. We also...
All-optical two-way relaying is an advanced techniques that helps to improve the data-rate and throughput of free-space optical (FSO) communication systems. In this paper, we propose to implement all-optical two-way relaying in dual-hop FSO systems using network coding. The relay node that is based on optical regenerate-and-forward relaying is equipped with an all-optical XOR gate and optical hard-limiters...
Two-way transmission protocol is an efficient method to overcome the spectral loss incurred due to half-duplex communication. In this paper, we propose to implement two-way transmission in an amplify-and-forward (AF) relaying free-space optical (FSO) system utilizing an AF relay with optical amplifier. The performance of the proposed FSO system using subcarrier intensity modulation (SIM) with intensity...
Free-space optical communication (FSO) is a line-of-sight (LOS) technology that enables data transmission based on the propagation of light in free space. Compared to radio frequency (RF) communication systems, FSO ones provide high data rates, unregulated bandwidth, high security, and low power. Therefore, FSO systems are rapidly gaining interest as an effective means of transferring data at high...
In this paper, we propose to use spatial pulse position modulation (SPPM), which is the combination of optical spatial modulation (SM) and pulse position modulation (PPM), as a powerful technique to improve the performance of free-space optical communication (FSO) systems. We analyze the performance of proposed system taking into account most major effects of FSO channel including geometric spreading...
We theoretically analyze the performance of free-space optical (FSO) communication systems using rectangular quadrature amplitude modulation (QAM) and avalanche photodiode (APD) over atmospheric turbulence channels. The log-normal fading channel is used in the analysis. We derive the system's average symbol error rate (SER) taking into account the APD shot noise and thermal noise, turbulence strengths,...
In this paper, a model of Gaussian pulse propagation over atmospheric turbulence channel is used to comprehensively analyze the performance of PPM-based free-space optical communication (FSO) systems with APD receiver. This model simultaneously takes into account all effects of atmospheric turbulence including intensity fluctuation and pulse broadening, which has not been considered in previous works...
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