Fiber

By Josh Adelson, director, Portfolio Marketing, CommScope

U.S. mobile operators reported a combined 50 terabytes of cellular traffic during the 2018 Super Bowl, nearly doubling over the previous year. In fact, Super Bowl data consumption has doubled every year for at least the past 6 years and it shows no sign of slowing down.

Clearly, fans love their LTE connections almost as much as they love their local team. Fans have the option for cellular or Wi-Fi, but cellular is the default connection whereas Wi-Fi requires a manual connection step that many users may not bother with.[1] The same dynamic is playing out on a smaller scale in every event venue and commercial building.

Whether you are a venue owner, part of the team organization or in the media, this heightened connectivity represents an opportunity to connect more with fans, and to expand your audience to the fans’ own social connections beyond the venue walls.

But keeping up with the demand is also a challenge. High capacity can come at a high cost, and these systems also require significant real estate for head-end equipment. Can you please your fans and leverage their connectedness while keeping equipment and deployment costs from breaking the capex scoreboard?

Virtualization and C-RAN to the rescue?

Editor’s note: This post is part of Mobile Sports Report’s new Voices of the Industry feature, in which industry representatives submit articles, commentary or other information to share with the greater stadium technology marketplace. These are NOT paid advertisements, or infomercials. See our explanation of the feature to understand how it works.

Enterprise IT departments have long since learned that centralizing and virtualizing their computing infrastructures has been a way to grow capacity while reducing equipment cost and space requirements. Can sports and entertainment venues achieve the same by virtualizing their in-building wireless infrastructures? To answer this question, let’s first review the concepts and how they apply to wireless infrastructure.

In the IT domain, virtualization refers to replacing multiple task-specific servers with a centralized resource pool that can be dynamically assigned to a given task on demand. Underlying this concept is the premise that, while each application has its own resource needs, at any given time only a subset will be active, so the total shared resource can be less than the sum of the individual requirements.

How does this translate to in-building wireless? Centralizing the base station function is known as C-RAN, which stands for centralized (or cloud) radio access network. C-RAN involves not only the physical pooling of the base stations into a single location — which is already the practice in most venues — but also digital architecture and software intelligence to allocate baseband capacity to different parts of the building in response to shifting demand.

C-RAN brings immediate benefits to a large venue in-building wireless deployment. The ability to allocate capacity across the venue via software rather than hardware adds flexibility and ease of operation. This is especially important in multi-building venues that include not only a stadium or arena but also surrounding administrative buildings, retail spaces, restaurants, hotels and transportation hubs. As capacity needs shift between the spaces by time of day or day of week, you need a system that can “point” the capacity to the necessary hot spots.

C-RAN can even go a step further to remove the head-end from the building campus altogether. Mobile network operators are increasingly deploying base stations in distributed locations known as C-RAN hubs. If there is a C-RAN hub close to the target building, then the in-building system can take a signal directly from the hub, via a fiber connection. Even if the operator needs to add capacity to the hub for this building, this arrangement gives them the flexibility to use that capacity in other parts of their network when it’s not needed at the building. It also simplifies maintenance and support as it keeps the base station equipment within the operator’s facilities.

For the building owner, this architecture can reduce the footprint of the on-campus head-end by as much as 90 percent. Once the baseband resources are centralized, the next logical step is to virtualize them into software running on PC server platforms. As it turns out, this is not so simple. Mobile baseband processing is a real-time, compute-intensive function that today runs on embedded processors in specialized hardware platforms. A lot of progress is being made toward virtualization onto more standard computers, but as of today, most mobile base stations are still purpose-built.

Perhaps more important for stadium owners is the fact that the base station (also called the signal source) is selected and usually owned by the mobile network operator. Therefore the form it takes has at most only an indirect effect on the economics for the venue. And whether the signal source is virtual or physical, the signal still must be distributed by a physical network of cables, radios and antennas.

The interface between the signal source and the distribution network provides another opportunity for savings. The Common Public Radio Interface (CPRI) establishes a digital interface that reduces space and power requirements while allowing the distribution network — the DAS — to take advantage of the intelligence in the base station. To leverage these advantages, the DAS also needs to be digital.

To illustrate this, consider the head-end for a 12 MIMO sector configuration with 4 MIMO bands per sector, as shown below. In this configuration a typical analog DAS is compared with a digital C-RAN antenna system, with and without a CPRI baseband interface. In the analog systems, points of interface (POIs) are needed to condition the signals from the different sources to an equal level before they are combined and converted to optical signals via an e/o (electric to optical) transceiver. In a digital system, signal conditioning and conversion from electric to digital is integrated into a single card, providing significant space saving.

* A typical analog system will require 8 POIs (4 MIMO bands per sector) and 2 o/e transceivers per sector resulting in 10 cards per sector. A typical subrack (chassis) supports up 10-12 cards, so a subrack will support 1 MIMO sector. For 12 MIMO sectors, 12 subracks are needed and each is typically 4 rack unit height. This results in a total space of 48 rack units.

* For a digital system[2] without CPRI, each subrack supports 32 SISO ports. Each MIMO sector with 4 MIMO bands will require 8 ports resulting in supporting 4 MIMO sectors per subrack. For 12 MIMO sectors, 3 subracks of 5 rack unit height each are needed resulting in total space of 15 rack units.

* For a digital system with CPRI, each subrack supports 48 MIMO ports. Each MIMO sector with 4 MIMO bands will require 4 ports resulting in 12 MIMO sectors per subrack. For 12 MIMO sectors, only 1 subrack of 5 rack unit height is needed resulting in total space of 5 rack units.

One commercial example of this is Nokia’s collaboration with CommScope to offer a CPRI interface between Nokia’s AirScale base station and CommScope’s Era C-RAN antenna system. With this technology, a small interface card replaces an array of remote radio units, reducing space and power consumption in the C-RAN hub by up to 90 percent. This also provides a stepping-stone to future Open RAN interfaces when they become standardized and commercialized.

The Benefits in Action — A Case Study

Even without virtualization, the savings of digitization, C-RAN and CPRI at stadium scale are significant. The table below shows a recent design that CommScope created for a large stadium complex in the U.S. For this, we compared 3 alternatives: traditional analog DAS, a digital C-RAN antenna system with RF base station interfaces, and a C-RAN antenna system with CPRI interfaces. Digital C-RAN and CPRI produce a dramatic reduction in the space requirements, as the table below illustrates.

The amount of equipment is reduced because a digital system does in software what analog systems must do in hardware, and CPRI even further eliminates hardware. Energy savings are roughly proportional to the space savings, since both are a function of the amount of equipment required for the solution.

Fiber savings, shown in the table below, are similarly significant.

The amount of fiber is reduced because digitized signals can be encoded and transmitted more efficiently.

But these savings are only part of the story. This venue, like most, is used for different types of events — football games, concerts, trade shows and even monster truck rallies. Each type of event has its own unique traffic pattern and timing. With analog systems, re-sectoring to accommodate these changes literally requires on-site physical re-wiring of head-end units. But with a digital C-RAN based system it’s possible to re-sectorize from anywhere through a browser-based, drag and drop interface.

The Bottom Line

It’s a safe bet that mobile data demand will continue to grow. But the tools now exist to let you control whether this will be a burden, or an opportunity to realize new potential. C-RAN, virtualization and open RAN interfaces all have a role to play in making venue networks more deployable, flexible and affordable. By understanding what each one offers, you can make the best decisions for your network.

Josh Adelson is director of portfolio marketing at CommScope, where he is responsible for marketing the award-winning OneCell Cloud RAN small cell, Era C-RAN antenna system and ION-E distributed antenna system. He has over 20 years experience in mobile communications, content delivery and networking. Prior to joining CommScope, Josh has held product marketing and management positions with Airvana (acquired by CommScope in 2015) PeerApp, Brooktrout Technology and Motorola. He holds an MBA from the MIT Sloan School of Management and a BA from Brown University.

FOOTNOTES
1: 59 percent of users at the 2018 Super Bowl attached to the stadium Wi-Fi network.
2: Dimensioning for digital systems is based on CommScope Era.

Kyle Field, Texas A&M University. Credit all photos: Texas A&M

Editor’s note: The following is an excerpt from our recent Stadium Tech Report series COLLEGE FOOTBALL ISSUE, a 40-page in-depth look at Wi-Fi and DAS deployment trends at U.S. collegiate football stadiums. You can download the full report for free, to get more stadium profiles as well as school-by-school technology deployment capsules for both the SEC and Pac-12 conferences.

When Texas A&M’s newly renovated Kyle Field opens for the 2015 football season, its outside appearance will have changed dramatically. But from a networking perspective, what’s really different is hidden on the inside – namely, an optical fiber infrastructure designed to bring a new level of performance, cost savings and future-proofing to stadium network deployments.

While the use of optical fiber instead of copper cable in large networks isn’t exactly “new” in the core telecom or enterprise networking worlds, in the still-nascent field of stadium network deployments fiber has yet to make large inroads. But the promise of fiber’s ability to deliver much higher performance and greater future-proofing at lower installation costs in stadium situations may get a very visible poster child when Texas A&M’s football facility kicks off the 2015 season with a technology infrastructure designed to be among the most comprehensive in any stadium, collegiate or professional.

With a Wi-Fi network designed to support 100,000 concurrent connections, a robust DAS network with more than 1,000 antennas, and an IPTV deployment with more than 1,000 screens, the IBM-designed network based largely on Corning’s fiber-optical systems is incredibly impressive on paper – and it has already produced some eye-popping statistics this past season, when just a part of it came online during the “Phase 1” period of the two-phase $450 million Kyle Field renovation.

The final, or Phase 2 of the renovation, just now getting underway, began with an implosion of the stadium’s west stands, with reconstruction scheduled to finish in time for the 2015 season with a new, enclosed-bowl structure that will seat 102,512 fans. And if the new network delivers as planned, those fans will be among the most-connected anywhere, with plenty of future-proofing to make sure it remains that way for the foreseeable future – thanks to fiber.

Driving on the left side of the street

What’s going to be new about Kyle Field? According to news reports some of the creature comforts being added include redesigned concession stands, so-called “Cool Zones” with air conditioning to beat the Texas heat, well-appointed luxury suites and new restrooms – including 300 percent more women’s bathrooms.

Scoreboard, Kyle Field

According to representatives from the school, the decision to make the new stadium a standout facility extended to its network infrastructure. “Our leadership decided that [the stadium renovation] would be leading edge,” said Matthew Almand, the IT network architect for the Texas A&M University System, the administrative entity that oversees university operations, including those at the flagship school in College Station, Texas. “There were some leaps of faith and there was a decision to be leading edge with technology as well.”

Though the Phase 1 planning had started with traditional copper cable network design for the network, Almand said a presentation by IBM and its “smarter stadium” team changed the thinking at Texas A&M.

“The IBM team came in and did a really good job of presenting the positive points of an optical network,” Almand said.

Todd Christner, now the director, wireless business development at Corning, was previously at IBM as part of the team that brought the optical idea to Texas A&M. While talking about fiber to copper-cable veterans can sometimes be “like telling people to drive on the left side of the street,” Christner said the power, scalability and flexibility of a fiber network fit in well with the ambitious Kyle Field plans.

“The primary driving force [at Texas A&M] was that they wanted to build a state of the art facility, that would rival NFL stadiums and set them apart from other college programs,” Christner said. “And they wanted the fan [network] experience to be very robust.”

With what has to be one of the largest student sections anywhere – Christner said Texas A&M has 40,000 seats set aside for students – the school knew they would need extra support for the younger fans’ heavy data use on smartphones. The school officials, he said, were also concerned about DAS performance, which in the past had been left to outside operators with less than satisfactory results. So IBM’s presentation of a better, cheaper alternative for all of the above found accepting ears.

“It was the right room for us to walk into,” Christner said.

IBM’s somewhat radical idea was that instead of having separate copper networks for Wi-Fi, DAS and IPTV, there would be a single optical network with the capacity to carry the traffic of all three. Though the pitch for better performance, far more capacity, use of less space, and cheaper costs might sound a bit too good to believe, most of it is just the combination of the simple physics advantages of using fiber over copper, which are well known in the core telecom and large-enterprise networking worlds, applied to a stadium situation.

Deploying now and for the future

Corning ONE DAS headend equipment.

Without going too deeply into the physics or technology, a simple explanation of the benefits stem from the fact that optical fiber can carry far more bandwidth than copper, at farther distances, using less power. That advantage is one reason why fiber is used extensively in core backbone networks, and has been creeping slowly closer to the user’s destination, through deployments like Verizon’s FiOS.

Why hasn’t fiber won over completely? Mainly because in single-user deployments – like to a single home or office – it is still costly to replace systems already in the ground or in the wall with fiber, and for many users fiber’s capacity can be a bit of overkill. Fiber’s main benefits come when lots of bandwidth is needed, and the scale of a project is large, since one main benefit is the elimination of a lot of internal switching gear, which takes up space and consumes lots of power.

Those reasons accurately describe the perfect bandwidth storm happening in networked stadiums these days, where demand seems to keep increasing on a daily basis. Some stadiums that were at the forefront of the wireless-networking deployment trend, like AT&T Park in San Francisco and AT&T Stadium in Arlington, Texas, have been in a near-constant state of infrastructure upgrades due to the ever-increasing needs for more bandwidth. And Isaac Nissan, product manager for Corning ONE, said new equipment like Wi-Fi access points with “smart” or multiple-input antennas are also going to help push the LAN world into more fiber on the back end.

But there’s another drawback to using fiber, which has less to do with technology and more to do with history: Installers, integrators and other hands-on networking folks in general are more comfortable with copper, which they know and have used for decades. Fiber, to many, is still a new thing, since it requires different skills and techniques for connecting and pulling
wires, as well as for managing and administering optical equipment.

“There’s definitely a learning curve for some the RF [industry] people, who have been doing coax for 20 years,” Nissan said. “Fiber is a little different.”

Texas A&M’s Almand admitted that bringing the stadium’s networking group into a new technology – fiber – was a challenge, but one with a worthy payoff.

Copper cable tray hardly filled by optical fiber

“There’s definitely been a gear-up cycle, getting to a new confidence level [with fiber],” Almand said. But he added that “sometimes it’s good to break out of your comfort zone.”

Lowering the IDF count

Christner said the Corning optical gear is at the center of the Kyle Field deployment, providing support for the fan-facing Wi-Fi as well as Wi-Fi for back of the house operations like point of sale; it also supports the stadium DAS, as well as a network of more than 1,000 IPTV screens. Aruba Networks is the Wi-Fi gear supplier, and YinzCam is helping develop a new Kyle Field app that will include support to use smartphones as remote-control devices for IPTVs in suites.

On the Wi-Fi side, Christner said the finished network will have 600 APs in the bowl seating areas, and another 600 throughout the facility, with a stated goal of supporting 100,000 concurrent 2 Mbps connections. The DAS, Christner said, is slated to have 1,090 antennas in 50 sectors.

With no intermediate switching gear at all, Christner said that for the fiber network in Kyle Field only 12 intermediate distribution frames (the usually wall-mounted racks that support network-edge gear, also called IDFs) would be needed, as opposed to 34 IDFs in a legacy fiber/coax system. In addition to using less power, the cabling needed to support the fiber network is a fraction of what would have been needed for coax.

One of the more striking pictures of the deployment is a 36-inch wide cable tray installed for the original copper-network plan, which is carrying just 10 inches of fiber-optic cable. Christner said the fiber network also provides a cleaner signal for the DAS network, which already had a test run this past season, when 600 DAS antennas were deployed and lit during the 2014 season.

“At the Ole Miss game we had 110,663 fans at the stadium, and according to AT&T on the DAS all their lights were green,” Christner said. “Via our completely integrated fiber optic solution, we are now able to provide the DAS with much higher bandwidth as well,” said Texas A&M’s Almand, who also said that the carriers have responded very positively to the new DAS infrastructure.

Up from the dust – a model for the future?

Antenna and zone gear box near top of stands

Also included in the design – but not being used – are an additional 4,000 spare fibers at 540 zone locations, which Christner said can be immediately tapped for future expansion needs. And all of this functionality and flexibility, he added, was being built for somewhere between one-third and 40 percent less than the cost of a traditional copper-based solution.

The proof of the network’s worth, of course, will have to wait until after the west stands are imploded, the new ones built, and the final pieces of the network installed. Then the really fun part begins, for the users who will get to play with things like 38 channels of high-def TV on the IPTV screens, to the multiple-angle replay screens and other features planned for the mobile app. At Texas A&M, IBM’s support squad will include some team members who work on the company’s traditionally excellent online effort for the Masters golf tournament, as well as the “smarter stadium” team.

For Texas A&M’s Almand, the start of the 2015 season will mark the beginning of the end, and a start to something special.

“If I were a country singer, I’d write something about looking forward to looking back on this,” Almand said. “When it’s done, it’s going to be something great.”

Can virtualization help venues meet growing mobile capacity demands?

Virtualization and C-RAN to the rescue?

The Benefits in Action — A Case Study

The Bottom Line

Stadium Tech Report: Corning, IBM bringing fiber-based Wi-Fi and DAS to Texas A&M’s Kyle Field

Driving on the left side of the street

Deploying now and for the future

Lowering the IDF count

Up from the dust – a model for the future?

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