& cplSiteName &

The Importance of BBU Emulation

Sterling Perrin
9/22/2017
50%
50%

Lately, we’ve focused on steps needed for operators to get their RAN ready for their next mobile technology evolutions -- including advanced 4G standards and, ultimately, 5G. (See Beyond CPRI: Planning for 5G Fronthaul and Preparing the Transport Network for 5G: The Future Is Fiber.)

While the industry continues to debate the pros and cons of technologies (Ethernet vs. CPRI) and architectures (distributed RAN vs. centralized RAN), they must not lose track of the basic, practical steps that should also be taken along the way. In this blog, we discuss the importance of BBU emulation as part of the overall test process for turning up cell sites.

In today's mobile networks, the base transceiver station (BTS) has been separated into two components -- the remote radio head (RRH) located at the top of the cell tower next to the antennas and the baseband unit (BBU) below. In most 4G networks, the BBUs typically sit at the base of the tower. The newest trend in 4G -- and certainly with 5G -- is to centralize BBUs in central offices, several kilometers away from the cell towers. This is called centralized RAN, or C-RAN.

Significantly, whether building out distributed RANs or new centralized RANs, BBU emulation is an important part of the turn-up process, along with connector inspection and fiber characterization. In cell site construction (whether distributed RAN or C-RAN), BBUs may not be installed or commissioned until after the cell tower is handed over to the mobile network operator. At this point, the mobile operator may find that cell tower transmissions aren't working properly -- or at all -- and a time-consuming and costly process ensues to find the cause of the transmission degradation or failure.

Ideally, cell tower installers would have the tools available at the time of installation to ensure that, when the mobile operators deploy their BBUs, all cell tower components and connections will be in working order. BBU emulation accomplishes this goal by imitating BBU transmission and RRH communication without requiring an actual BBU in the network. Here are some important tests that installers can perform by adding this relatively simple testing step:

  • Identify RF interference source: Installers/technicians will learn if there is any RF signal interference associated with the cellular transmission. If the RF interference occurs across multiple antennas on the tower, it is mostly likely an external source -- which could include anything from nearby Sonet equipment to old cable amplifiers or even baby monitors in the area. A single antenna interference indicates an internal source, such as a coax cable defect or a faulty antenna.

  • Passive intermodulation (PIM) testing: PIM is mixing of sub-carriers caused by defects in the mechanical components of a wireless system, comprised of antennas, transmission lines and related components. Similar to RF interference, PIM sources can be internal -- such as rusted elements or bad connectors -- or external -- such as nearby metal pipes or roofing. The BBU emulator can identify PIM as well as help determine whether that source is internal or external.

  • Fiber cable installation validation: Mixing up fiber connections to the RRH is a common cell tower installation error. BBU emulation can be used to assure that all fibers are connected to the correct RRHs and the correct antennas/direction (sectors).

  • Antenna and coax cabling validation: While fibers connect the BBU to the RRHs, coax connects the RRH to the antennas. BBU emulation can be used to ensure that the coax cabling is wired correctly and performing to the mobile operator's specifications. Using BBU emulation, mobile operators can instruct the RRH to perform a return loss measurement and related voltage standing wave ratio (VSWR) measurement which will provide an assessment of the quality of the coax and antenna connections.

To be clear, each of the problems detected by BBU emulation could also be diagnosed by the mobile operator once the BBU is commissioned at the tower. The value in BBU emulation lies in detecting faults during installation and prior to commissioning to avoid lengthy and costly delays in service turn-up and help them generate new revenue streams faster.

— Sterling Perrin, Principal Analyst, Heavy Reading

This blog is sponsored by EXFO.

(0)  | 
Comment  | 
Print  | 
Newest First  |  Oldest First  |  Threaded View        ADD A COMMENT
More Blogs from Heavy Lifting Analyst Notes
NFV is shifting from a technology focus to operations, as CSPs say too much effort has been spent on VNF onboarding and too little on the reality of operations.
The converged fiber access market is set to grow again, especially as copper lines continue to deteriorate.
The most recent Thought Leadership Council (TLC) survey finds that opportunities abound for 5G vendors as only 15% of TLC service providers have chosen their vendors for the 5G market.
The ability of artificial intelligence (AI) to carry out complex analysis on high volumes of data very quickly could help automate many telco security activities. But is it smart to cut humans out of the loop?
Cable is turning to artificial intelligence (AI) to help tackle customer service woes, as well as proactively manage network functions and provide a better customer experience.
Featured Video
From The Founder
Light Reading founder Steve Saunders grills Cisco's Roland Acra on how he's bringing automation to life inside the data center.
Flash Poll
Upcoming Live Events
March 20-22, 2018, Denver Marriott Tech Center
March 22, 2018, Denver, Colorado | Denver Marriott Tech Center
April 4, 2018, The Westin Dallas Downtown, Dallas
May 14-16, 2018, Austin Convention Center
All Upcoming Live Events
Hot Topics
MWC 2018 Threatens to Be 5G New Radio Bore
Iain Morris, News Editor, 1/10/2018
Sprint Says No to mmWave, Yes to Mobile 5G
Dan Jones, Mobile Editor, 1/11/2018
Altice USA Embraces Home-Alone Strategy
Alan Breznick, Cable/Video Practice Leader, Light Reading, 1/11/2018
Clark Quite the Catch for Troubled Synchronoss
Ray Le Maistre, International Group Editor, 1/10/2018
Animals with Phones
Customer Support Done Right Click Here
"You've reached 'Who's a Good Boy?' How can I direct your call?"
Live Digital Audio

A CSP's digital transformation involves so much more than technology. Crucial – and often most challenging – is the cultural transformation that goes along with it. As Sigma's Chief Technology Officer, Catherine Michel has extensive experience with technology as she leads the company's entire product portfolio and strategy. But she's also no stranger to merging technology and culture, having taken a company — Tribold — from inception to acquisition (by Sigma in 2013), and she continues to advise service providers on how to drive their own transformations. This impressive female leader and vocal advocate for other women in the industry will join Women in Comms for a live radio show to discuss all things digital transformation, including the cultural transformation that goes along with it.

Like Us on Facebook
Twitter Feed