RESUMO
Adaptive analog beamforming is a key technology to enable spatial control of millimeter-wave wireless signals radiated from phased array antennas (PAAs) which is essential to maximize the capacity of future mobile networks and to ensure efficient usage of scarce spectrum. Intermediate frequency-over-fiber (IFoF), on the other hand, is a promising technology for the millimeter-wave (mm-wave) mobile fronthaul due to its low complexity, high optical spectral efficiency, and low latency. The combination of IFoF and PAA is key to implement mm-wave mobile communications in a scalable, centralized, efficient, and reliable manner. This work presents, for the first time to the best of the authors' knowledge, an extensive outdoor measurement campaign where an experimental IFoF mm-wave wireless setup is evaluated by using PAAs with adaptive beamforming on the transmitter and receiver sides. The configuration of the experimental setup is according to 5G standards, transmitting signals wirelessly at 27 GHz central frequency in the n258 band. The employed PAAs are composed of 8-by-8 patch antenna arrays, allowing beam steering in the azimuth and elevation angles. Furthermore, different end-user locations, antenna configurations, and wireless scenarios are tested in the outdoor experiment, showing excellent EVM performance and achieving 64-QAM transmission over up to 165.5 m at up to 1.88 Gbit/s. The experimental results enable optimization of the experimental setup for different scenarios and prove the system's reliability in different wireless conditions. In addition, the results of this work prove the viability and potential of IFoF combined with PAA to be part of the future 5G/6G structure.
RESUMO
Physical layer encryption methods are emerging as effective, low-latency approaches to ensure data confidentiality in wireless networks. The use of chaotic signals for data masking is a potential solution to prevent a possible eavesdropper to distinguish between noise and sensitive data. In this work, we experimentally demonstrate the W-band wireless transmission of a 1 Gb/s chaotic signal over 2 m in a radio-over-fiber architecture. The chaos encoding scheme is based on the transition between different states of a Duffing oscillator system, digitally implemented. The bit error rate achieved in all cases was below the forward error correction limit for 7 % overhead. The presented results validate the proposed chaos-based physical layer encoding solution for gigabit data transmissions in hybrid millimeter-wave/photonic networks.
RESUMO
This paper discusses spatially diverse optical vector network analysis for space division multiplexing (SDM) component and system characterization, which is becoming essential as SDM is widely considered to increase the capacity of optical communication systems. Characterization of a 108-channel photonic lantern spatial multiplexer, coupled to a 36-core 3-mode fiber, is experimentally demonstrated, extracting the full impulse response and complex transfer function matrices as well as insertion loss (IL) and mode-dependent loss (MDL) data. Moreover, the mode-mixing behavior of fiber splices in the few-mode multi-core fiber and their impact on system IL and MDL are analyzed, finding splices to cause significant mode-mixing and to be non-negligible in system capacity analysis.
RESUMO
The performance and potential of a W-band radio-over-fiber link is analyzed, including a characterization of the wireless channel. The presented setup focuses on minimizing complexity in the radio frequency domain, using a passive radio frequency transmitter and a Schottky diode based envelope detector. Performance is experimentally validated with carriers at 75-87GHz over wireless distances of 30-70m. Finally the necessity for and impact of bend insensitive fiber for on-site installation are discussed and experimentally investigated.
