The long-wire dipole antenna is effective for low-frequency systems. Adding LC traps makes a single-band dipole antenna into a multiband unit. The historically significant long-wire dipole antenna may seem like an anachronism in these days of compact, highly mobile wireless devices operating in the gigahertz spectrum, but that’s not the case at all. Due to…
What’s the difference between a VCSEL and PCSEL?
A vertical cavity surface-emitting laser (VCSEL) relies on a three-dimensional (3D) structure for light emission. A photonic crystal surface-emitting laser (PCSEL) incorporates a 2D photonic crystal (PhC) layer to manipulate light emission. Those structural differences lead to different performance and application possibilities. An obvious difference between the various types of semiconductor lasers is the beam…
What is DRX (Discontinuous Reception) in LTE?
Discontinuous Reception (DRX) is a power-saving mechanism in LTE networks designed to extend the battery life of user equipment (UE), such as smartphones. This FAQ will begin by explaining the Physical Downlink Control Channel (PDCCH) role in LTE from the DRX perspective. Then, it will illustrate the complete DRX process with short/long DRX cycles and…
What is precoding? What does it do?
Precoding is a signal processing technique that modifies the phases and amplitudes of wireless signals to combat channel distortion and optimize the quality and reliability of data transmissions. It can support beamforming in multiple-input, multiple-output (MIMO) and massive MIMO antenna arrays. This article reviews some of the benefits of precoding, looks at how it’s implemented,…
FAQ on the bias tee
A conceptually simple passive component is used to combine or split DC and RF signals; however, its implementation has many subtleties. The RF world, operating at hundreds of megahertz and into the gigahertz range, is known for having many unusual components. Some are unique to that higher-frequency world, while others appear at lower frequencies but…
How 5G network slicing works: part 2
Network slicing, which makes private networks possible, provides enterprises with dedicated network resources. It works by interacting with a set of network functions. Part 1 of this series covered how 5G network slicing enables operators to deploy, modify, and scale customized virtual networks, along with key slicing techniques and connectivity models. Part two discusses the…
Overcome Open RAN test and certification challenges
LaaS Testing can streamline deployment and enhance efficiency for reliable Open RAN The race to build 5G networks has gone on for several years, extending coverage and providing access to advanced services. Initiatives such as Open RAN make for high-performing, robust, and agile mobile infrastructures that are in the interest of consumers and businesses, as…
How 5G network slicing works: part 1
Network slicing, which makes private networks possible, provides enterprises with dedicated network resources. It works by interacting with a set of network functions. The 3GPP defines network slicing as a core 5G feature. It partitions a single physical network into multiple virtual network slices. Each slice operates as an independent end-to-end network optimized for specific applications and services. This…
DSL router uses parts from old phones
A consortium of companies found a clever way to recycle phone parts, showing how reusing electronics can improve sustainability. Electronic waste is a huge environmental problem of which disposed cell phones are a major contributor. Think about it, all that metal, plastic, and working semiconductors go into landfills. Some materials, such as gold from PCB…
FAQ on the Butler matrix for beamforming: part 1
This passive beamforming topology is not well known but is widely used — a common situation in the RF world. For many years, radar applications defined much of the world of directional antennas. These antennas were designed with a fixed directivity or rotated in a steady pattern at a known rate, as seen in Figure…