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Densification, Densification, Densification!

By Nick Marshall
March 15th, 2016

Screen Shot 2016-03-14 at 12.00.03 PMJust like in real estate there are 3 keys to success in the world of radio coverage and capacity distribution and they are, in no particular order, Densification, Densification and Densification. This is particularly important at the edge of the network where it connects to subscribers’ handsets, smartphones, tablets and other end points like IoT or M2M sensors.

Where is the Edge?

The Edge is where the mobile signals from the macro tower start to run out of range and a user starts to experience a drop in data rate or lack of coverage. This is caused by any number or combination of factors including RF signal attenuation due to physical impairments, obstructions or interference, and the dynamic requirements of users. The Edge can be outdoors, in a building or venue or in high traffic density locations like stadiums and underground in subways.

Living on the Edge…

The macro cellular network is simply not designed for life at the edge as demand for coverage and capacity is dynamic with rapidly changing coverage requirements and capacity demands. With more mobile devices (think smartphone, tablets, laptops and IoT/M2M) requiring wireless connectivity, access points at the edge need to become much more dense, dynamic and proactive. In some respects the Edge must proactively follow the traffic demand. Mobile traffic is “tidal.” For example there is more demand for capacity in an enterprise between 9am and 5pm during week days than outside of working hours. At a major sporting event outside a stadium on game day the capacity demand is in the car-park before the game and that traffic shifts to the stadium for the game and then back to the car park for after the game. On days which are not game days demand falls to virtually zero.

Screen Shot 2016-03-14 at 11.59.27 AMWhat do we mean by Edge Densification?

Edge Densification is a major trend and has been the driver behind Heterogeneous Networks (HetNets) for some time now. It means increasing the radio throughput per square meter by any means possible in both the Transport and Access layers of the RAN.

In Transport, this means maximizing fiber allocation from the carrier’s demarcation point deep into the Edge, leveraging both CWDM and DWDM to enable Centralized RAN (C-RAN) architectures now and using NFV and SDN to transition to Cloud RAN in the future. Fiber transport can function both as backhaul and fronthaul and is a critical part of C-RAN and basestation hoteling. It also enables virtualization of the baseband in the cloud or data center as well as MEC (Mobile Edge Computing) or IT functionality at the Edge to further increase densification.

In the Access layer, densification techniques would include using more efficient protocols such as LTE with carrier aggregation or aggregating with Wi-Fi in the unlicensed bands for data offload, 3GPP standards such as eICIC, CoMP and higher order QAM and MIMO can all be deployed to densify the Edge and increase throughput per square meter.

Although still to be specified, densification will continue into 5G as one of the drivers of a massively dense small cell underlay/overlay. This will probably operate in the millimeter wave bands with short range and low power for high frequency reuse.

Together Transport and Access can be used to enable the increases in coverage and capacity needed for Edge Densification. Using Edge Densification, MNOs can respond to the exploding growth in data traffic and the proliferation of wireless connections to subscribers and to IoT devices. The MNO must densify its network and balance between maximizing the use of a limited asset or spectrum with ever more efficient transport such as DWDM and access protocols such as LTE-Advanced Pro or 5G, and obtain an increase in throughput per square meter of its network while lowering TCO.

Are There Edge Densification Business Models?

The traditional MNO ecosystem has reached a level of “Capex Exhaustion” for in-building and venue densification and property and venue owners must look towards neutral hosts or 3rd party owners (3PO), value added resellers (VARs) and system integrators to deploy and densify their in-building networks. 3PO’s like Tower companies and infrastructure owners are already stepping up in the US – many Towercos are reporting significant double digit leasing revenue growth in recent earnings. VARs are leveraging multiple OEM relationships to handle the maximum variety of deployment scenarios. There is also an emerging role to be played by the building owners and real estate companies themselves to deploy DAS in the “middleprise.” Neutral host and SCaaS offerings from small cells are emerging to compete with traditional DAS systems as do the various “flavors” of Wi-Fi – LWA, LTE-U, LAA and MulteFire.

Screen Shot 2016-03-14 at 12.00.44 PMWhat are the Opportunities and Obstacles for Edge Densification?

In the US the majority of the big venues have been done and DAS is readily available. According to the US government there are 335,000 commercial buildings with floor area >50,000 square feet for a total of 44 billion square feet in the US today. With < 6% aggregate floor space penetration by in-building wireless systems there is a huge opportunity – this is the Middleprise. In addition with in-building traffic growing 7X by 2020 and 4G and Wi-Fi outpacing that to reach a staggering 53 Exabytes/month by 2020, there is a clear need for densification.

SOLiD at MWC 2016

I recently had the pleasure of discussing this topic on a panel at MWC 2016 with Ken Sandfeld – President and CEO of SOLiD North America, Ray LaChance – Co-Founder and CEO of ZenFi Networks and Chris Jaeger Managing Director Transit Systems/Large Venues from BAI Communications. BAI’s subsidiary Transit Wireless built and operates the New York City Subway DAS which runs over ZenFi fiber and uses SOLiD DAS equipment.

You can watch the videos here:


The New York City Subway is one of the World’s oldest (1st station opened in 1904 [world’s oldest is London-1890]) and largest (by number of stations). There are 422 stations in the New York Subway system, and Transit Wireless equipped the 279 of these which are underground. This is the World’s largest DAS – 279 subway stations, with 1.6 billion riders/year (averages 5.3 million during the week, 3 million on Saturdays and 2.4 million on Sundays) and a great example of Edge Densification.

(Learn more about this project here)

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