Earlier this month, companies and vendors from across the wireless industry came together at Verizon’s facility in Irving, Texas to test 4G LTE technology over the CBRS (Citizen Band Radio Spectrum) spectrum. After the successful initial trials last year, Corning, Ericsson, Federated Wireless, Google, Nokia and Qualcomm Technologies are all collaborating in end-to-end system testing.
The CBRS band is made up of 150 MHz of 3.5 GHz shared spectrum, which until now has been primarily used by the federal government for radar systems. The FCC authorized shared use of the spectrum with wireless small cells in 2016. By using LTE Advanced technology, carrier aggregation and the spectrum access system (SAS), Verizon will be able to use this shared spectrum to add capacity to its network.
The end-to-end system tests are designed to accomplish several goals on the path to widespread commercial deployment:
Corning provided a SpiderCloud Enterprise RAN composed of a Services Node and SCRN-330 Radio Nodes. Ericsson’s Radio System solution is comprised of 4×4 MIMO, 4x20MHz Carrier Aggregation, including CBRS spectrum delivered over infrastructure aggregating Ericsson’s outdoor micro base station (Radio 2208 units) with the indoor B48 Radio Dot System in the same baseband (5216 units). Nokia provided FlexiZone Multiband Indoor BTS, FlexiZone Multiband Outdoor BTS and FlexiZone Controller.
In addition, participants in this ecosystem have set up private LTE sites which are using CBRS spectrum. Private LTE networks are being engineered to meet the needs of enterprise customers who want greater control over their LTE solutions including private on-site servers, control over access to their designated LTE network, as well as increased throughput and reduced latency through dedicated backhaul.
The end-to-end system testing, which began in February and will continue over the next several weeks, has provided actionable insights and have significantly advanced CBRS spectrum deployment feasibility.
“The promise of the CBRS band and enabling the use of wider swaths of spectrum will make a big impact on carrying wireless data in the future. These trials are critical to stress test the full system,” said Bill Stone, VP technology development and planning for Verizon. “There are many players in the CBRS ecosystem and these successful trials ensure all the various parts perform together as an end-to-end system for our customers’ benefit. We want to ensure devices efficiently use CBRS spectrum and that the new components effectively interact with the rest of the network.”
At the conclusion of this testing, equipment will be submitted for certification through the FCC. Following that deployment can then begin. Both commercial deployment of LTE on CBRS spectrum and devices that can access the CBRS spectrum are expected to begin in 2018.
CommScope, Ericsson Complete SAS Interoperability Testing for CBRS
To help ensure their readiness for commercial deployment in the CBRS wireless spectrum, CommScope and Ericsson have successfully completed interoperability testing of their equipment. The testing is one of the first successful interoperability tests using the Wireless Innovation Forum’s release 1.2 specifications.
“CommScope’s team of architects, developers and engineers have been building an industry-leading SAS for nearly two years,” said Tom Gravely, vice president of research and development, Network Solutions, CommScope. “Completion of interoperability testing with a major radio equipment provider such as Ericsson validates our SAS design and readies us for commercial deployment.”
The interoperability test confirmed that CommScope’s Spectrum Access System (SAS) and Ericsson’s radio infrastructure with CBRS spectrum support will work together as part of a CBRS network. The rigorous SAS–Citizens Broadband Radio Service Device (CBSD) interoperability testing used a battery of scenarios to verify that both products meet governmental requirements and industry protocols, as well as CommScope’s and Ericsson’s respective quality standards.
“Ericsson offers a comprehensive portfolio of CBRS network solutions that will help operators of all sizes deploy in this spectrum quickly and successfully,” said Paul Challoner, vice president of Network Product Solutions, Ericsson. “Additional milestones need to be reached for CBRS to become a reality, but we are pleased to complete interoperability testing with CommScope as part of the developmental process.”
In a CBRS network, a SAS and CBSD work together to ensure that the appropriate wireless signals are transmitted and received between the core network and end-user devices, while managing interference. An Environmental Sensing Capability (ESC) works with the SAS to identify the wireless signals of incumbent users to avoid interference from CBSDs. CommScope is one of four ESC operators conditionally approved by the FCC to provide SAS and ESC services.
The reasoning behind Corning’s purchase of SpiderCloud Wireless, which was announced in late July, echoes a trend throughout the wireless industry as it tries to solve the puzzle of providing wireless in the enterprise space.
“The solution needs to be cost effective, enable for multiple operators, create opportunities for new business models for cost sharing and you gotta have a signal source,” said Mike Collado, director, applications marketing – wireless. He believes that is just what will result from the combination of Corning One and SpiderCloud Wireless.
Corning began working with SpiderCloud a couple of years ago looking to evolve in-building wireless beyond the choice of either a multi-operator DAS or single-carrier small cells.
“We saw networks evolving toward a combination end-to-end solution of a centralized base band with flexible distribution to the edge,” Bill Cune, vice president, commercial technology wireless, said.
The purchase of SpiderCloud is the latest step in the in-building wireless space for Corning, which got its start in DAS by purchasing MobileAccess, a hybrid fiber/coax DAS OEM, in 2011. Two years later, Corning Optical Network Evolution (ONE) wireless platform was developed, which pushed fiber-optics out to the antenna and enabled convergence of DAS with WiFi and small cell backhaul.
Formed in Palo Alto, California in 2008, SpiderCloud Wireless provided self-organizing (SON) small cell networks for enterprises and it was an approved radio access network (RAN) vendor for several carriers, but it was single-operator system.
“SpiderCloud brings to Corning its expertise in LTE baseband and small cell, and Corning brings its capabilities in multi-operator active at the antenna networking to the table,” Cune said.
Along with all the wireless carriers, the Corning ONE infrastructure can converge building automation, security and Wi-Fi, among other networks.
Corning brings its extensive experience and channels developed while selling optical fiber and DAS to enterprises. “Most of SpiderCloud’s selling activities have targeted the carriers,” Cune said. “The top three verticals for Corning ONE are commercial real estate, hospitality and sports entertainment/large venue. Close behind is the healthcare market.”
To maximize the benefits of Corning’s market access, SpiderCloud will be integrated into the Corning Optical Communications business.
July 25, 2017 —
The problem for in-building wireless communications coverage, as Mike Collado explained it, is that the macro wireless network was never designed or engineered to support in-building wireless for today’s connected world. Collado serves as Corning’s director of wireless applications marketing, and he spoke earlier this year at the Network Infrastructure Forum, a part of the International Wireless Communications Expo. Collado said that among those with an interest in having in-building wireless coverage are wireless service users, mobile network operators, building owners and public safety agencies.
Mobile network operators focus their efforts on developing and sustaining their macro networks, Collado said. They pay attention to quality of service and the cost per bit of delivering service. He said buildings that lack good, reliable wireless coverage and capacity cost their owners revenue. Moreover, owners could face legal liabilities and public relations failures for not having wireless coverage and capacity in their buildings if something bad happens. He said social media readily spreads the word when coverage in a building is poor, and that’s not good for property owners.
Public safety agencies want in-building coverage so their increasingly complex wireless devices, which now include more functions than two-way radio, work properly indoors to help with their tasks and to help their first-responders do their jobs safely, Collado said. “And I would argue that users rely upon their smartphones in order to stay safe,” he said. “You don’t think about pulling a fire alarm because remember we were taught in elementary school, ‘Don’t touch the fire alarm.’ You call 911.”
Among developments spurring the need for in-building wireless systems are energy efficiency and commercial building codes. Building owners’ desire to obtain Leadership in Energy and Environmental Design (LEED) green-building certification motivates them to install energy-efficient reflective glass. Collado said the glass wreaks havoc on RF. “It creates either a dark building or a shadow building,” he said. “A LEED building can block the macro network from reaching another building.”
Commercial building codes increasingly are requiring owners to enable their buildings for indoor public safety wireless communications. “There are new stakeholder roles in order to make this work with wireless operators retreating from playing a starring role in funding and owning and operating these networks,” Collado said. “Others are going to step up and play new and different roles. All of those roles are going to have to align and intertwine to develop and deliver the desired results and outcomes.”
What’s in the Toolkit
Three categories of tools in what Collado called the in-building wireless toolkit can be used to construct indoor systems: legacy, current and emerging tools (see Figure 1). Various tools help to achieve desired outcomes based on the type of building and the needs and requirements of users, operators, owners and public safety agencies.
Legacy tools include signal boosters, such as bidirectional amplifiers, which Collado said are sold for broadband communications. Another legacy tool, repeaters, uses digital signal processing and channelization. And a third legacy tool is passive distributed antenna system (DAS) networks, one type of which is consists of leaky coaxial cable.
Passive DAS uses signal amplification at one end of a length of leaky coaxial cable through which the signal radiates. As a result, Collado said, the greater the distance from the amplifier, the more the signal strength diminishes. A more sophisticated passive DAS uses amplification at the headend, and coaxial cable feeds a series of antennas throughout the structure.
Current tools include active analog DAS, which needs a signal source. The signal can be taken off the air, although Collado said it often works better if the wireless carrier places a base station at the headend to supply the signal. He said an analog DAS converts RF to light, sends the light through fiber-optic cable for the risers, and then converts the light back to RF for the horizontal runs.
Another current tool is small cells, which Collado classifies into two types: picocells and microcells, and e-femtocells that use the internet as backhaul to the carrier core. Other small cells, such as Ericsson Radio Dot and SpiderCloud, have direct connections with the carrier core.
A third current tool is voice over Wi-Fi. Collado said whether voice over Wi-Fi provides satisfactory wireless telephone calls depends on the quality of the building’s Wi-Fi connection.
Among what Collado calls emerging tools are some that reimagine existing tools and others that represent innovations. One is active digital DAS. “With active digital DAS, as opposed to looking at it from an RF perspective, it’s IP,” he said. “It’s a more intelligent DAS system. You’re able to fine-tune what is distributed to each antenna.”
Because the key to DAS is a signal source and distribution, Collado said a pragmatic approach uses small cells as the signal source, followed by active analog DAS or active digital DAS to distribute the signal throughout a building.
Collado said centralized DAS involves collocating the headend equipment. It places the large base stations and other space-consuming gear in another location, perhaps a less expensive real-estate location separate from the building to be served or, if there are space constraints, it puts the base station where it’s possible to deploy it. The collocated headend gear then uses a fiber path to distribute the signal into the building.
With cloud DAS — sometimes called virtualized DAS — essentially the signal source is in the cloud, which refers to computer servers in a data center linked via the internet.
Other emerging tools that use unlicensed spectrum operate at 5 GHz. “Using unlicensed spectrum offers a way to enable LTE in a building to help augment the capacity of the wireless network to provide the desired quality of service or quality of experience in the building,” Collado said.
The Citizens Broadband Radio Service (CBRS) offers the use of shared spectrum that Collado said holds the promise of enabling third parties, neutral hosts and building owners to own and operate wireless networks somewhat independently of the wireless network operator. “CBRS is a new initiative that is gaining traction and momentum,” Collado said. “It may take years for it to become real because the chipsets in smartphones have to enable and support CBRS.”
Generally, the enterprise needs to step up and own or fund part, if not all, of the infrastructure for enabling the in-building coverage, Collado said. He said that measured as a cost per square foot, certain technologies lend themselves better than others that could be deployed in small, medium-size and large buildings or venues.
Collado described a case study for what he called the middleprise, or a building from 100,000 square feet to 500,000 square feet in size (see Figure 2). “They’re hotels. They’re office buildings. They’re residential buildings. In this case, we’re going to look at new construction for a hotel with 350,000 square feet.” Collado said certain things need to happen.
“First of all, you will have a public safety communications requirement for a new building,” he said. “That could depend on the location or municipality and what signals must be delivered to support public safety operations in that jurisdiction. You could use signal boosters to support multiple public safety signals and frequencies cost effectively. Or, potentially, you may need to use a public safety DAS, which is more expensive, depending on how many public safety frequencies it must carry.”
Guests expect Wi-Fi service, so the hotel will have to have to be fitted with Wi-Fi access points. Collado said it’s impossible to control which wireless carriers guests will be using with their phones, so the Wi-Fi service has to support multiple network operators.
Ways to Enable Coverage
A hybrid solution could be used with a middleprise installation, such as the hotel in this example. Collado said a small cell could provide the signal source, and a DAS could distribute the signal in the building. “Cloud DAS is a more virtualized signal source and very much an emerging technology in the toolkit,” he said. “That could be a potential way. Using unlicensed and shared spectrum could be a couple of years down the road, but those are all ways to enable in-building coverage and capacity in this middleprise type of scenario.”
Collado said the emerging tools in the kit require not only developing innovative technologies, but also new business models that align the needs the user, the building owner, the carrier and public safety agencies. “What a great time to be in the wireless industry to solve some of these new and deep challenges,” he said.
Corning and Zhone Technologies have agreed to co-market an all-fiber network solution capable of deploying passive optical local area network (POL) and cellular DAS on a common infrastructure –– Corning’s ONE Wireless Platform. The result will be quicker installation, a smaller equipment footprint, and lower cost for enterprise companies. In the past, companies needed to use solutions from multiple vendors to build separate information technology and cellular networks. Leveraging Zhone’s innovative POL solution, FiberLAN, and Corning’s ONE Wireless Platform, customers can now deploy an integrated fiber network solution that includes both the electronics and passive fiber optic components in one converged solution. www.corning.com
When Corning announced the installation of a DAS at the World Market Center in Las Vegas, this month, it was the second such announcement since November when it deployed DAS in a multi-building marketplace at AmericasMart in Atlanta.
Troy Suddith, director, Solutions and RF Engineering, Corning, told AGL Small Cell Link, that the vendor has done several merchandising venues recently and they each have their own morphology that demands different wireless solutions.
“They are massive buildings filled with vendors, distributors and merchandisers,” he said. “For the carriers, these are key public venues because they drive so much capacity, and there is such a desire for good coverage by the venues themselves, which want the events to go well for the exhibitors and the people attending.”
With 6 million square feet, World Market Center is one of the largest showroom complexes for the home and hospitality furnishings industry. AmericasMart, a global wholesale marketplace, contains 7 million square feet of space across three buildings and 15 floors, including showrooms and exhibit halls.
Although the facilities are similar in size, the DAS solutions were different. The signal requirement for the World Market Center was much higher than AmericasMart (15 dBm to 17 dBm higher RF target), because of the dominance on nearby macrocells, and the intermediate distribution frame locations were not as prevalent as in the AmericasMart, which meant the coax runs from the remotes were longer.
Corning deployed its MobileAccessHX two-watt amplifier solution at the World Market Center. “Pretty much everything being deployed today is capacity-driven,” Suddith said. “Our 2-watt HX allowed us to drive coax farther distances from the remotes at the IDF and to dominate the macrocell.”
Likewise, with less macrocellular dominance inside the buildings, Corning used a more traditional low-power solution: the MobileAccess 2000 QSX and TSX solution (20 dBm output power) with a dedicated amplifier.
Enterprise DAS Morphed in to Neutral Host System
Originally, the World Market Center came to Corning through a carrier as an enterprise deal. It was designed as a single-carrier design initially in summer of 2012. Six months later, the carrier came back to Corning and wanted it changed to be a neutral-host DAS.
“We designed the MobileAccessHX in a way that we could easily swap one component and change it from single carrier to neutral host,” Suddith said. “The two-watt solution, which has one port, is designed with a one-by-four splitter, which we could add other HX remotes later. We swapped out a one-by-four with a four-by-four combiner, allowing us to add three other carriers.”
The operator required quad-band MIMO with a plan to deploy LTE on all frequencies at the World Market Center. So two boxes were deployed in each remote location for two streams. The equipment deployment included 97 remote locations, 194 boxes and 776 antennas.
Multiple-building DAS Presents Cabling Challenges
Having multiple adjacent buildings in a venue can help or provide a challenge from a design perspective. One of the challenges for the hybrid fiber/coax-fed DAS system in AmericasMart, for example, was getting fiber from the head end to all the remote locations.
“It can be a lot of fiber if their multiple buildings. In AmericasMart, what we leveraged was a single-fiber wave division multiplexing (WDM) solution that allowed us to have remotes at each building,” Suddith said.
A head end was positioned in one building and Corning used its 330 System to consolidate the fiber and remotes were placed in the other two buildings. Therefore, shorter distances were required for the multiple fiber runs to the individual remotes in each building, versus pulling all of them to the head end in one building.
“It is a consideration of what type of fiber you have and what type of through-way you have for fiber-optic cabling. It significantly reduces the amount of fiber needed for multiple buildings,” Suddith said. “In the World Market Center, however, there were plenty of conduits for us to run fiber from the head end to the remotes in each building.”
The AmericasMart supports LTE MIMO DAS, comprising nearly 1,300 antennas and more than 250 fiber-fed remotes.