Beyond 5G Fronthaul Based on FSO Using Spread Spectrum Codes and Graphene Modulators.

High data rate coverage, security, and energy efficiency will play a key role in the continued performance scaling of next-generation mobile systems. Dense, small mobile cells based on a novel network architecture are part of the answer. Motivated by the recent mounting interest in free-space optical (FSO) technologies, this paper addresses a novel mobile fronthaul network architecture based on FSO, spread spectrum codes, and graphene modulators for the creation of dense small cells.

High gain/bandwidth off-chip antenna loaded with metamaterial unit-cell impedance matching circuit for sub-terahertz near-field electronic systems.

An innovative off-chip antenna (OCA) is presented that exhibits high gain and efficiency performance at the terahertz (THz) band and has a wide operational bandwidth. The proposed OCA is implemented on stacked silicon layers and consists of an open circuit meandering line. It is shown that by loading the antenna with an array of subwavelength circular dielectric slots and terminating it with a metamaterial unit cell, its impedance bandwidth is enhanced by a factor of two and its gain on average by about 4 dB.

Performance evaluation of an IMDD optical OFDM-CDMA system.

In this paper, we propose a modulation technique for passive optical networks that harnesses two-dimensional prime hop system optical code division multiplexing access (OCDMA) and optical orthogonal frequency-division multiplexing (OFDM) for intensity modulation with direct-detection (IMDD) to enhance users' signal capacity in a cost-effective manner. The theoretical analysis is built from an analytical formula that takes into account both multiple-access interference and photodetector noise. Results show that OFDM-OCDMA with multiple users has similar performance to single-user conventional OOFDM for low transmitted powers.

Management of acute upper gastrointestinal bleeding in a district hospital.

Background: This study was conducted to assess the management of acute upper gastrointestinal bleeding in a district hospital and to compare these results with national guidelines and the published literature.

Materials And Methods: This prospective and retrospective study included 112 patients, mean age 66 years, who presented with acute upper gastrointestinal bleeding between July 2004 and February 2005. All patients were assigned a Rockall risk assessment score.