White Paper
Network Modernization
Four practical solutions for cost-effectively modernizing your network
Philip Sorrells
Chris Stockman
August, 2015
Contents
Introduction3
Network modernization challenges
3
An overview of solutions
4
Simplifying the top of the tower
4
Choosing the right fiber connectivity
5
Solving PIM 7
The advantages of a pre-assembled approach 7
Conclusion8
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Introduction
The task of modernizing a network is becoming increasingly more complex. Every network
must be updated to replace aging technology, but the modernization process is an evolving
target. As consumers purchase newer, more advanced mobile devices, the demand to increase
bandwidth only compounds that need.
To meet increasing capacity requirements all the way up to 4G, wireless service providers are
upgrading from conventional sites to top-of-the-tower remote radio unit (RRU) sites. With the
pressure to add capacity, improve performance and cut operating costs—all while finding an
affordable, reliable upgrade path—more and more providers are turning to fiber-to-the-antenna
(FTTA) connectivity. As technology continues to evolve—pumping more data through towers
using less spectrum—radio frequency (RF) performance standards are becoming more stringent.
If you are tackling the formidable task of modernizing your network, a comprehensive, wellinformed viewpoint is your most valuable asset.
Network modernization challenges
Although the network modernization process has many moving components and layers
of complexity, there are several major challenges broadly experienced by the majority of
providers:
•Multiple spectrum bands and technologies
•Protecting your current system
•Deploying RRUs at the top of the tower
•Ensuring future readiness
•Time to market
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An overview of solutions
There are many paths to network modernization, but providers must choose solutions that
cost-effectively address their unique capacity needs and establish a foundation for addressing
future technology evolutions. In this white paper, we’ll focus on four practical solutions for
modernizing both existing and new towers:
•Simplifying the top of the tower with multiport antennas
•Choosing the right fiber connectivity
•Effectively addressing passive intermodulation (PIM)
•Pre-assembled and factory-installed deployments
The key objectives of a successful migration
What is the best network modernization strategy for you? What are the best outcomes from
any combination of approaches? To start, your solution should:
•Minimize weight and wind load on strained towers
•Achieve the performance required to justify the investment
•Decrease capital and operational expenses (CapEx and OpEx)
•Reduce the risk of installation errors
•Be easy to upgrade and maintain
•Be repeatable and scalable
Simplifying the top of the tower
When you focus on the critical assets and technology at the top of the tower, the path to
network modernization can be challenging. One of the most difficult challenges is predicting
future architecture. This is, arguably, the most complicated variable, often hiding costs for
installs and maintenance, and often increasing the chances for error. The physical challenges
of wind load and tower safety with added weight are also major concerns. Equipment may not
be flexible enough to support current and future applications and services.
These issues and uncertainties add risk to the implementation process. As a result, providers are
placing a premium on flexible solutions.
The antenna approach
The top of the tower is especially challenging for new antennas. Crowded tower tops not only
increase leasing costs, but often lead to installation headaches that drain resources. Antennas
in close physical proximity to each other can distort patterns and impact signal performance.
Service is also susceptible to interference between bands.
The use of multiple antennas also makes a wireless system vulnerable to failure. Each additional
antenna or associated piece of equipment adds another layer of complexity and, with it,
an opportunity for disruptive and costly equipment failure. Simply put, the more individual
components added to the top of the tower, the more susceptible you make your network to
downtime. Of course, recurring disruptions in service or performance issues can significantly
impact a provider’s image, as well as the likelihood of reduced revenues from dropped
subscribers who want fast and dependable service. Faced with loaded towers, interference
issues and the threat of downward-trending revenue, wireless service providers want solutions
that can safely and easily blend technologies, simplify tower architecture and perform reliably.
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Multiport antennas are ideal for simplifying and facilitating several bands and technologies.
Multiple ports add the capability to support a variety of technologies in a single panel. Instead
of numerous dedicated technologies apportioned between an array of antennas, providers
gain a more versatile network structure capable of supporting multiple technologies and
operator sharing.
From a structural perspective, multiport antennas can help reduce tower load. From a financial
perspective, this approach also reduces CapEx.
The ultra-wideband option
Wireless service providers are looking for ways to roll out new services that support the
latest wireless device capabilities while continuing to provide services for older technologies.
Uncertainty about future frequencies makes this challenge more complex. Along with this
uncertainty is the practical matter of tower space: it’s often very difficult to find a viable spot for
installing new equipment.
Ultra-wideband technology is an ideal solution for providers facing these issues. This
technology provides a clear path to the future with multiport antennas, dual-band towermounted amplifiers (TMAs) and combining solutions that allow for sharing of antennas and
feeders. Ultra-wideband solutions provide flexibility for multiple services operating from one
antenna. This capability makes it much easier to overlay LTE onto 2G and 3G networks
that are using GSM and UMTS bands. In areas where LTE in lower bands may need to be
deployed in the future, this technology allows for a solid investment that reaps immediate
benefits while significantly reducing costs for future antenna upgrades.
For example, one base station antenna can essentially be used in place of six to provide
services for GSM, CDMA, W-CDMA and LTE standards in 698–960 MHz and 1710–2690
MHz bands. Many older antennas were deployed when PIM wasn’t a concern, which means
the equipment is not meeting today’s PIM specification requirements for fast data rates and
throughput. Older antennas can be replaced with new Argus® Ultra-Wideband models to support
old and new services in virtually any frequency used within 698–960 and 1710–2690 MHz
bands. This solution saves tower space and offers the flexibility needed for future frequency wins.
Argus® Ultra-Wideband Antennas give you
global performance in one package.
698—960 MHz + 1710—2690 MHz
At its core, ultra-wideband technology allows wireless service providers to implement new
frequencies without adding more antenna faces. It’s ideal for complex networks that feature a
variety of technologies and physical layers. Key benefits include:
•Increased speed to market and a cleaner, more visually attractive site
•The ability to support all major air-interface standards in almost any frequency range
•A reduced number of network antennas for lower tower leasing costs
•Greater performance in capacity-sensitive, data-driven environments
Choosing the right fiber connectivity
As newer RRU technology replaces conventional base transceiver station (BTS) units on the cell
tower, more advanced optical fiber is replacing coaxial cable as the top choice for today’s
antenna applications, especially in outfitting and retrofitting hardware for FTTA applications.
In a typical FTTA configuration, baseband units (BBUs) communicate with RRUs via Internet
Protocol (IP) signaling over fiber-optic cable. A short-length coaxial cable jumper is used only
for RF transmission between the RRU and the antenna—an approach much different than a
conventional radio transceiver connected to antennas via one long coaxial cable.
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Figure 1
This configuration offers several advantages. First, it eliminates the need for long, heavy coaxial
cables. Second, it reduces weight load. Third, it minimizes RF losses. Finally, BBU cooling needs
are greatly reduced; less air conditioning equipment means less space and power requirements.
There are two basic ways to approach tower connections: a single hybrid cable containing
both fiber and power, or separate power and fiber cables run in parallel (Figure 1). A hybrid
configuration combines power and fiber conductors in a single, high-performance cable for
greater efficiency, capacity and savings. Hybrid cabling has many other practical benefits,
including lower install costs, quicker deployments, greater durability, easier upgrade paths
and redundancy.
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A hybrid system should be robust and flexible enough to withstand the test of time and
accommodate future changes. Select a cable with fiber counts that provide double or triple
redundancy, along with power conductor counts and sizes that support your anticipated RRU
quantity and future power requirements. The next consideration is choosing the breakout system
that best facilitates connectivity with the RRU. Traditional junction boxes—or a new streamlined
method using pre-connectorized canisters integrated directly into the trunk cable—are two
popular breakout methods. The advanced canister option eliminates the need for a junction
box and allows a provider to use a single, universal hybrid fiber trunk cable that mates to RRU
specific cable tails. These tails are configured at one end to match the specific fiber and
power inputs of the different RRU brands and models in the industry and plug into the canister
at the other.
When changes are made at the tower top, only a simple change of cable tails is required.
Expansion is also accomplished in similar fashion. Redundant power and fiber elements from
the trunk are simply connected through the pre-connectorized canister or junction box with tails
and run to the new RRU.
Solving PIM
When assessing network modernization options, every wireless service provider must address
the pervasive and growing challenge of PIM. PIM is the result of two or more wireless signals
mixing together to create undesired frequencies that cause interference or degrade the
transmission of signals. With today’s newer technologies, PIM can pose a significant threat to
network quality.
When resolving PIM issues, providers should consider two major factors: RF cable assemblies
and challenges at the top of the tower. The integrity and quality of your RF cable assembly
technology is a crucial factor in minimizing PIM. Many tower components can contribute to
PIM, especially as they age, becoming more susceptible to corrosion. It’s important to choose
components that are pre-tested and PIM certified. We will explore PIM in greater detail in a
subsequent white paper as part of our Network Modernization series.
The advantages of a pre-assembled approach
Beyond addressing PIM, providers must constantly replace aging technology. Advances in
mobile devices and the race to increase bandwidth make it an ongoing necessity to update
existing towers and build new ones. Today’s extremely complex tower tops present a significant
challenge in this area. A pre-assembled sector solution can help overcome it by applying
cost-savings, consistency and performance benefits.
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CommScope is an innovator in this area, offering Andrew® SiteRise™, the world’s first preassembled tower tops for RRU site architectures. The pre-assembled sector solution is radio
access network (RAN) vendor-neutral. It supports up to four RRUs per sector and virtually
all radio frequency bands, from 700 MHz to 2690 MHz. Since only one assembly unit is
mounted to the tower per sector, SiteRise decreases OpEx by reducing long-term leasing,
maintenance and labor costs.
Conclusion
Every provider should consider the complexity and cost of network modernization. It raises
many questions:
•What is the most cost-effective path to FTTA?
•What is the right approach to connections?
•What are the pros and cons of fiber versus hybrid?
•How can we minimize the PIM issue?
•How can you simplify the top of the tower?
•How can you prepare for future frequency bands?
A comprehensive, holistic network modernization strategy tailored to your specific requirements
will help you maximize performance and durability while paving the way for future upgrades.
Fortunately, there are viable, proven solutions that can help you modernize your network—
affordably and efficiently.
Interested in more information about network modernization?
This is the first in a new series of Network Modernization white papers published by
CommScope. Subsequent papers will delve into greater detail on many of the technical
aspects, logistics and costs of the modernization process.
www.commscope.com
Visit our website or contact your local CommScope representative for more information.
© 2015 CommScope, Inc. All rights reserved.
All trademarks identified by ® or ™ are registered trademarks or trademarks, respectively, of CommScope, Inc.
This document is for planning purposes only and is not intended to modify or supplement any specifications or warranties relating to CommScope products or services.
WP-106918.1-EN (08/15)
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