Distributed Antenna Systems (DAS)
- Anyone new to distributed antenna systems who wants to learn how it works
- Designers and installers involved in projects with DAS cabling
- Managers and supervisors involved in projects with DAS cabling
Objectives: From this self-study program you should learn:
- How distributed antenna systems are designed to maximize coverage
- How cabling connects all elements of a distributed antenna systems
- What types of cabling (copper or fiber) are used in distributed antenna systems
- Issues in designing and installing distributed antenna systems cabling.
When you finish, you can take an online exam on this course to qualify for a "Fiber U Certificate of Completion."
Wireless traffic is growing at a phenomenal rate. AT&T says their cellular data traffic grew 50,000% (that's 500 times) between 2007 (the introduction of the iPhone) and 2014. The landscape is covered with cellular towers but the majority of cellular connections (70-80% for both voice or data) originate inside buildings, so wireless coverage inside buildings has become more important. Cellular wireless signals often cannot penetrate walls and even windows in large buildings, requiring low-power cellular antennas placed inside buildings to provide reliable service.
The 49ers stadium has over 700 antennas as part of its DAS
There are several other reasons for cellular systems inside buildings or structures. Sometimes the number of users inside a building like a convention center or sports facility exceeds the bandwidth of a single cellular system. In many areas, local laws specify the need for public safety radio signal coverage (fire, police, emergency) inside every building that requires indoor antenna coverage. Auto or mass transit tunnels are also obvious applications for cellular distributed antenna systems.
A distributed antenna system is a fairly straightforward installation, similar to a LAN connected to the Internet with one major exception - a DAS may be shared by all cellular service providers rather than be limited to one user or one ISP. DAS for most facilities will use fiber backhaul for the cellular connections because of the bandwidth requirements. Small buildings may use an antenna on the roof and coax cable for distribution inside the facility, called a Passive DAS, but they are becoming rare. DAS cabling resembles structured cabling or OLAN cabling and in fact can share the backbone cables if there are sufficient fibers available. Since most DAS cabling is singlemode, compatibility with the new generation GPON OLAN which uses singlemode fiber is easiest.
DAS digital electronics are usually from one of two standard system types set up by manufacturers for compatibility. Cabling has no standard although TIA is working on such a document, but it may take years to be finished and does not seem to cover the typical digital system architectures. Manufacturers of the equipment or service providers generally dictate the cabling architecture and specifications. So as is the FOA’s procedure, we will summarize the options and provide guidance on how the DAS is generally designed and built and not spend our time on standards that will be changing continuously! We do however try to keep our references up to date.
In addition to the information on DAS design and cabling options, we include links in this self-study program to information relevant to installation.
You will be instructed to read the references or watch videos and take the quiz (Test Your Knowledge) to complete the "classroom" part of the course.
Watch The Video
FOA YouTube Video Lecture 40, Distributed Antenna Systems
Read The Online FOA Reference
FOA Reference Guide, Fiber For Wireless
FOA Reference Guide, Distributed Antenna Systems
Test Your Knowledge - DAS Cabling Quiz
When you finish the assignments and case study, you can take an online exam on this course to qualify for a "Fiber U Certificate of Completion." The exam cost is $20US.
Go here to take the Fiber U DAS Certificate of Completion exam. Here are detail directions if this is your first time taking a Fiber U Certificate of Completion exam.
This information is provided by The Fiber Optic Association, Inc. as a benefit to those interested in teaching, designing, manufacturing, selling, installing or using fiber optic communications systems or networks. It is intended to be used as an overview and/or basic guidelines and in no way should be considered to be complete or comprehensive. These guidelines are strictly the opinion of the FOA and the reader is expected to use them as a basis for learning, as a reference and for creating their own documentation, project specifications, etc. Those working with fiber optics in the classroom, laboratory or field should follow all safety rules carefully. The FOA assumes no liability for the use of any of this material.