What is…?


Dark Fiber

Dark fiber refers to unlit fiber strands within a fiber optic cable.  Fiber optic cables are glass cables that are used to transmit communication signals through the use of light as a means for delivery.  Dark fiber is the most flexible connectivity option for carriers, large enterprises and institutions as it can support multiple services with different protocols simultaneously.  The full optical bandwidth of the fiber provides throughput limited only by the choice of end equipment, providing users the flexibility necessary to meet future demand for network capacity by simply deploying more capable hardware when and where it is needed.




Fronthaul Fiber

Fronthaul fiber is any fiber that extends beyond the base station to a remote antenna.  Traditionally used to serve indoor Distributed Antenna System (iDAS) and outdoor Distributed Antenna System (oDAS) aggregation, this type of fiber is also applicable for Remote Radio Heads (RRHs) that enable Light Footprint Macro Site deployment.  Fronthaul fiber is difficult to provide in traditional networks due to the lack of access to the core network, and since these networks weren’t built with the need for fiber-to-the-antenna in mind, fronthaul fiber has traditionally been an expensive option for carriers.  The ZenFi Access Network is specifically designed to support the deployment of fronthaul, and thus, provides a cost-effective option for carriers.



Passive Wavelength

Wavelength service refers to the splitting of light into wavelengths, providing parallel transmission of data on a single strand of fiber.  Wavelengths are measured in nanometers with fiber optics residing in 850, 1300, and 1550 nm. The ZenFi Passive Wavelength Service uses Dense Wavelength Division Multiplexing (DWDM) to provide optimal support for single protocol streams with throughput up to 100 Gbps.  With DWDM, wavelengths are closely spaced to be transmitted on a single fiber, making these services a favorable choice when users do not need the full spectrum of dark fiber, but still wish to maintain control of the network equipment.




Backhaul Fiber

Backhaul fiber is the connection between base station processing and the carrier core network.  Often used to support traditional macro site deployments and small cells, backhaul is also effective when used in the Light Footprint Macro Site model between the base station hotel and the carrier hub.  ZenFi provides customers with flexible backhaul options to the New York metro area’s largest carrier hotels, data centers and enterprise locations via our Express Network .  Connecting into our Access Network at major distributed colocation points across New York City, our Express Network and backhaul fiber solutions serve even the most bandwidth-intensive and business-critical requirements of carrier and enterprise customers.



Base Stations and Base Station Hoteling

A Base Station Hotel (BSH) is a location that houses multiple base stations.  In the context of mobile telecommunications, a base station is the processing unit responsible for connecting mobile devices and the wider cellular network.  The base station can be located either close to or far from the radio, which receives and transmits communications to the end-user.  Macro sites, small cells and Wi-Fi all have the radio and base station collocated; however, by contrast, aggregated DAS and Remote Radio Heads (RRHs) handle the conversion of analog-digital / digital-analog signal using fronthaul fiber to connect back to the base station for higher level processing.  Since base stations can be collocated and moved further into the core of a network utilizing fronthaul fiber, base station hotels offer a reduction in operating and CapEx costs to carriers.

Base station hotels provide a unique solution to housing and managing a multifaceted wireless network.  The BSH serves as a central point to house all wireless communications equipment within a purpose-built environment, optimally designed and stabilized to provide network assurance for communications gear.





The Distributed Antenna System, more commonly referred to as DAS, is a network architecture in which small antennas are distributed (in-building or outdoors) to provide additional coverage for a wireless provider.  DAS nodes are the remote communication nodes within a DAS network, and require lower power than macro sites.  Within this network, fronthaul fiber is utilized to connect the node to the hub site, where radio transceivers (or other headend equipment) propagate the communication signals from the field.  DAS nodes can support multiple carriers and technologies, making them highly flexible and scalable solutions.  However, a significant design component to DAS architecture is that it requires high-capacity transport coupled with expensive headend and node equipment, making the traditional DAS network expensive.  ZenFi works to lower the overall cost of DAS architecture by designing and deploying cost-effective fronthaul fiber.




Remote Radio Head 

A Remote Radio Head (RRH) connects an operator radio to a transceiver.  RRHs connect back to a base station using fronthaul fiber on a new protocol called the Common Public Radio Interface (CPRI).  The ZenFi Access Network enables fronthaul fiber connections between RRHs and their base stations.



Macro Site

Macro cell sites are at the core of wireless networks, providing wide area coverage of up to 10 miles or more in diameter for mobility users by way of cell towers.  These standalone or structure-attached cell towers come in varying forms including lattice, guyed, stealth and monopole, which climb as high as 250 feet and are installed with base station equipment cabinets beneath them.  Typical tower components include whip antennas, port holes, panels / antennas, microwave dishes, coaxial cabling (fiber), reinforcement bars, shelters, generator and ground space.  Their coverage is complemented by a combination of other technologies to increase network capacity, particularly in dense urban areas; these include DAS, Wi-Fi and small cell networks.

Macro cell towers are designed to accommodate multiple tenants and their many different technologies, including telephony, mobile data, broadcast television and radio.  While tower companies typically own the tower structures and ground interest, tenants can lease the vertical space on the macro cell tower as well as portions of the ground space beneath it for their equipment, including antenna arrays, antennas, coaxial cables, base stations and equipment shelters.

While traditional large macro sites have been an industry standard, they require substantial upfront capital investments, sizeable ongoing expenses for maintenance, leasing, power and backhaul, and are privy to difficult zoning restrictions. The ZenFi Light Footprint Macro Site  model is a cost-effective, any-to-many alternative for carriers looking to reduce costs and efficiently expand their networks.



Small Cell

Small cells are operator-controlled, low-powered radio access nodes that complement mobile phone service from larger macro cell towers.  Small cells range in size, from the compact femtocell serving residential customers, to the picocell used inside commercial offices, to the microcell, used for outdoor public spaces such as sports stadiums.  Developed for both 3G and 4G/LTE radio technologies, small cells have a range of 32 feet to approximately 1.2 miles.

Small cells provide a cleaner signal with less power, are easily to deploy and maintain, and can be mounted on street poles, bus stops, cell towers and rooftops.  Providing almost double the capacity of a macro cell, small cells have the potential to reduce the number of cell towers – even eliminate them completely in the future.  Using more small cells at macro cell sites also yields large improvements in capacity and data offload, as well as enhancements in macro network performance.

While a critical aspect of addressing today’s wireless capacity constraints, deploying small cells comes with its own set of challenges, including backhaul.  Traditional microwave systems used for mobile data backhaul require a clean line of site, typically not available with small cell deployments in dense urban settings like New York City, which are usually mounted low above ground.  The availability of fiber at the desired cell site and the cost of bringing it there is also a challenge.  The ZenFi Access Network provides a cost-effective and readily available fiber solution for aggregating and connecting high-capacity small cell clusters to our redundant fiber backhaul network as well as all major colocation facilities.




Wi-Fi is a wireless networking technology that leverages Radio Frequency (RF) technology to provide wireless high-speed Internet and network connections on “Wi-Fi Certified” applications and devices including mobile phones, home networks, video game consoles, operating systems, and more.   To enable Wi-Fi, an RF current is supplied to an antenna, creating an electromagnetic field that is able to propagate through space.

Requiring no physical wired connection between sender and receiver, Wi-Fi uses a Network Access Point (NAP), or hotspot, to connect wireless network adapters within Wi-Fi-enabled consumer electronics to network resources such as the Internet.  Computers within the range of the NAP detect the wireless signal broadcasted by the hotspot and connect.  This range can vary to approximately 66 feet indoors and up to 1.5 miles outdoors if using multiple overlapping access points.