5G DAS – Common Misconceptions

5G DAS Solutions are really the elephant in the room right now. Everyone wants to know if the Distributed Antenna System available today will support 5G. In short, yes they will, but YOU just might not be the first cab off the rank. The exact strategy of how 5G will be delivered over DAS continues to become clearer and evolve each day. Realistically, it will be a combination of delivery of 5G DAS as we know DAS today plus some small cell infrastructure in locations where the use case is justified.

But here we go again with the spruikers…

Uncertainty in the market creates opportunities for spruikers. We saw the same thing with the evolution to 4G and prior to that the Y2K ‘bug’. Whilst our conversations within the informed engineering community are united in approach. There is no doubt everyone is hopping on the 5G bandwagon creating a lot of misinformation and often misaligned from the end user’s best interests.

Lets clarify some big misconceptions that are being circulated around right now:

EDIT: Since writing this article, the new version of the MCF was released, which has thankfully dispelled a lot of what was called out below. Please find the full article on the new MCF here.

Misconception 1: Distributed Antenna Systems as we know them today will not support 5G infrastructure.

Reference to the transition to 5G in the MCF2018 Specification was based on a limited amount of information available at the time. Whilst a large portion of the discussion at the time focused on the high band (26GHz) 5G experiences there was limited discussion on a migratory path with reference to the 3400-3800MHz and existing bands.

What has become abundantly clear is that delivering 5G in the existing available bands will be part of the respective operator’s strategic spectrum ‘re-farm’ programs. This will involve the reallocation of the spectrum to support newer technologies. This approach has been adopted by the operators in the previous technology migration programs. This means that the migration will take time and won’t happen overnight. So, for those keen to be at the forefront 3800MHz support is key (which is still achievable over DAS as we know it today).

The table below highlights the evolutionary path of previous technologies as the spectrum is ‘re-farmed’ as well as the availability of hardware to support the different bands.

But do not take our word for it, like always you should do your own research. You don’t have to look far to find supporting evidence for this directly from the operators in both their own press releases and existing DAS sites with 5G being deployed on 2300MHz, 2600MHz and 3500MHz, all DAS Supporting bands.

850MHz spectrum to 5G by 2024. 

Optus 2300MHz now providing 5G Services

Misconception 2: The only DAS to deliver 5G will be fibre fed active antennas. All Passive DAS infrastructure is dead.

Through every iteration of technology we have seen that there is no “one size fits all”. Nothing is black and white, different use cases require different solutions. Active DAS has existed in various forms for some time. ‘Fully active’ antennas with ethernet/fibre (no coaxial) all the way to the antenna have been available for several years. The solution has its pros and cons and like any product are best used when they are the appropriate technical solution to address the dominant use case. Having had experience working on these systems when a product was shoehorned into the wrong site… it only brings a world of pain.

Fully Active systems combine antennas/remotes and are what some people traditionally think constitutes active DAS. Active DAS can also take a mixed approach in which the remote still feeds an element of passive system infrastructure. A remote can feed a coaxial system across a set of commercial building floors, keeping the expensive box tucked away in a base building riser for maintenance and upgrades may be a better solution at times.

Pushing the Active DAS intelligence to the ‘edge’ to use a computing comparison has a variety of pros and cons. But its not the ‘only’ way to deploy 5G by any means.

• A fully active system is typically quick to install, but significantly more expensive in hardware quickly dispelling any claims of it being cheaper.
• A fully active system provides the ability to granularly monitor the status of the system antenna by antenna, but you need to do that because there are more points of failure inherent to the topology.
• From an upgrade perspective, the passive coaxial elements have wideband support and flexibility. A high-power active DAS might require an additional remote in a common location to introduce a new band. In a fully Active Antenna environment, every piece of hardware needs a complete swap out.

You may get the impression we are saying there is no place for ‘Fibre to the Antenna Active DAS’. Not even in the slightest. We are an engineering first organisation that looks at the best solution for a particular environment based on user experience and importantly the total cost of ownership. This could mean a combination of all these systems in a mixed used precinct based on the demand and environment differences between retail, basements, and commercial space.

Where we get frustrated is blanket statements, and we have heard them all:

“Passive DAS is dead” – Wrong

“The only way to deliver 5G is a fully active fibre to the antenna DAS” – Wrong

“All new DAS needs to be MIMO” – Wrong

Ironically, we heard these exact claims in the migration from 3G to 4G, it takes a while for common sense to prevail and the spruikers to disappear until the next opportunity or in this case the next generation.

Misconception 3: We need 5G DAS now!

5G is a great step forward and while there are some interesting prospects in the low latency applications. For John Doe, it’s ultimately providing additional capacity (and speed) and a different logo on your phone, but it won’t reinvent the wheel overnight.

There are not many tangible use cases today for increased throughput. We are building the highway for future capacity as the rollout continues over the next 5-10 years. A recent comment (25/02/21) by Vodafone CEO Inaki Berroeta in announcing the company’s results highlighted the relevance of 4G moving forward. He said: “While we are accelerating our 5G rollout, Australians will still be relying on 4G for some years to come. To continue meeting customer demand we will enhance the 4G experience by expanding voice over LTE capability and virtualising our network”

However, if your current DAS is outdated, providing a poor experience for users and you are looking to replace your existing DAS then incorporating 5G or at least an upgrade path into the solution is a “no brainer”.

A lot of 4G DAS today is providing 250Mbps and upwards in a basic SISO configuration (see our recent installation at the MLC Centre). There are not a lot of uses cases for cellular devices which can justify this level of capacity today let alone anything in addition to this beyond bragging rights.

Consider how long 3G and 4G have coexisted. Today 3G is still live and scheduled for a 2024 shutoff. Likewise, in the future, we may migrate all our 4G bands to 5G and another generation of technology, but that is not imminent.

For a long time, phone calls were made on the 3G network while data was on 4G. Phone calls are now on the 4G network with some reseller based customers still on 3G in certain circumstances. Phone calls are not migrating to 5G anytime soon and the existing 4G infrastructure will continue to add value for a long time to come.

5G rollout will continue to add speed and capacity to further expand the network to suit our requirements for the next 5-10 years, but you don’t desperately ‘need’ it today and will be at no disadvantage in the interim.

DAS is no different from shopping for a Big Screen TV, there will always be something new that comes out tomorrow. But if tenants don’t have coverage today, with typical DAS projects in the 6-9 month range, there is an immediate issue to solve. As with all technology, there will always be something new on the horizon, but at any point in time, we can provide a variety of steps to future proof a DAS system for 5G based on the current technologies available.

Wireless Coverage Solutions DAS Designs have a variety of considerations to allow for future upgradability, including 5G. Contact us today to discuss your project’s needs