Exploring mmWave frequencies and adopting smallcell architectures are two key enablers for increased wireless data rates. To make these evolutions economically viable, centralized architectures based on radio-over-fiber (RoF) are devised. To reduce the complexity of the cellular network even further, RF-over-Fiber transmission schemes are adopted in combination with reflective uplink operation. This paper relies on a very low complexity narrowband GaAs electronics / Si photonics transceiver for scalable RFoF architectures with which we demonstrate a fiber-wireless link capable of transmitting over 7 Gb/s in down-and uplink for a 2 km fiber and 5 m wireless link in the 28 GHz band. Furthermore, it is shown that Rayleigh degradation caused by reflective uplink operation can be avoided by using a coherent detection scheme.

10Gb/s, 28GHz radio-over-fiber transmission using a directly-modulated single-mode C-band VCSEL is demonstrated over 2km. The chirp of the VCSEL is translated into intensity modulation to extend the fiber-reaches and increase the power budget with 10dB.

E-commerce, new retail, and other changes have highlighted the requirement of high efficiency and accuracy in the logistics service. As an important section in logistics and supply chain management, warehouses need to respond positively to the increasing requirement. The “smart warehouse” system, which is equipped with emerging warehousing technologies, is increasingly attracting the attention of industry and technology giants as an efficient solution for the future of warehouse development. This study provides a holistic view of operations management problems within the context of smart warehouses. We provide a framework to review smart warehouse operations management based on the characteristics of smart warehouses, including the perspectives of information interconnection, equipment automation, process integration, and environmental sustainability. A comprehensive review of relevant literature is then carried out based on the framework with four perspectives. This study could provide future research directions on smart warehouses for academia and industry practitioners.

For the first time, a personal exposimeter (PE) for 60 GHz radiation measurements is presented. The PE is designed based on numerical simulations and both on-body and on-phantom calibration measurements to determine the antenna aperture and measurement uncertainty of the PE. The measurement uncertainty of the PE is quantified in terms of 50% and 95% prediction intervals of its response. A PE consisting of three nodes (antennas) with VHH (vertical-horizontal-horizontal) polarization results in a 95% prediction interval of 6.6 dB. A 50% prediction interval of 1.3 dB (factor of 1.3) is obtained for measured power densities which is 3.1 dB lower than a single antenna experiment. The uncertainty is 19.7 dB smaller than that of existing commercial exposimeters at lower frequencies (≤6 GHz).

We present a low-power all-digital radio-over-fiber transmitter for beyond 28-GHz using sigma-delta modulation, a 140mW NRZ driver and parallel electro-absorption modulators. 5.25Gb/s (2.625Gb/s) 64-QAM is transported over 10-km SSMF at 1560nm with 7.6% (5.2%) EVM.