5G DAS (Distributed Antenna Systems)
5G deployments via Distributed Antenna Systems (DAS) are really the elephant in the room right now; everyone wants that 5G logo (even if they don’t know what they’ll do with it).
5G is being provided today in buildings via either a combination of DAS and small cells, where appropriate, to provide the end-to-end experience. 5G is being deployed on systems deployed within the last decade, to the systems being deployed today, but its all just different flavours of 5G offering differing levels of speed and capacity (in line with the system’s capabilities)
Don’t be fooled by the spruikers; this is not a 5G revolution that requires some new innovative approach to 5G DAS. It’s just a repeat of the cellular evolution that happens time and time again, from 3G to 4G and now 4G to 5 G. You don’t need a specific ‘product’ to enable 5G. It’s really about what cellular RF bands your system supports and the respective operators’ strategies for 5G DAS deployments.
Like any significant technology shift, there is a lot of media attention and hysteria that comes with it. Some people claim that today’s DAS solutions won’t support 5G, necessitating a completely new (and conveniently the specific hardware they sell) system. However, while some of these claims are true regarding limitations of existing sites, most are not, and the various DAS topologies that exist toady can continue to delivery 5G services
Likewise, we are seeing numerous specifications that demand fibre-fed active DAS solutions to improve the 5G upgrade path. Although well-intentioned, this approach often does more harm than good. In reality, these buildings do not warrant an active system due to their size. They would be better served with a Passive system, which would actually significantly improve their 5G upgrade paths by providing complete wideband support, while being infinitely more reliable. When FOMO kicks in people, start making decisions grounded in assumptions and fear, unfortunately, to make educated decisions right now its critical to get into the weeds and build up a basic knowledge of how DAS works and how a transition to 5G will take place.
5G includes a range of technologies across various bands, some of which will never be deployed over a conventional Distributed Antenna System, and there would be little reason to. Any spectrum above 6GHz will always be delivered over small cell infrastructure, and it will come at great expense; consequently, it will not be widespread, but it offers enormous capacity for areas that really need it.
Wireless Coverage Solutions has an entire 5G technology-focused article that breaks down 5G into its various technologies and offerings. An understanding that there are a variety of flavours of 5G is pivotal in understanding DAS’s role in the delivery of 5G. Below is a summary of the various 5G technologies and their direct relevance to DAS Systems.
You may have heard of these >6GHz 5G deployments as mmWave 5G, which includes features such as Massive MIMO and Beamforming. These are some seriously exciting technologies that can only be delivered when every antenna in a system is ‘intelligent’. This is typically the architecture of a small cell system (which doesn’t currently support true multi-operator implementations). There will be times and use cases in buildings for high-density locations where there may be a viable solution (food courts, airport lounges, stadiums) however, it would be rare (and expensive) to deploy such a system throughout the building. This is where DAS differs as more often than not its a building-wide solution, so we want to discuss building-wide 5G, and targetted hotspots are a separate conversation.
It has become apparent 5G DAS deployments are primarily happening in the sub 6GHz bands with the 3400-3800MHz bands, being a popular choice globally (and in Australia). This is important because the 3.5GHz 5G band can be supported by DAS components to varying degrees. In addition to the deployment of 5G on this new band, operators are rolling out low band 5G and refarming their existing spectrum. This involves the carriers re-farming their existing spectrum, something which we have seen previously in the migration from 2G, 3G, 4G and now 5G. Telstra has recently announced its plans to reuse the current 3G 850MHz spectrum to 5G by 2024. Likewise, Optus is looking to refarm their existing 2300MHz spectrum from 4G over to 5G enabling increased compatibility of New and Old Distributed Antenna Systems just through existing band support.
This is all great news for 5G Distributed Antenna Systems as it means that modern DAS will have an onramp into 5G, while you won’t be able to get 5G on a DAS system built-in 1999 (there are plenty still out there), there should be opportunities for a well-designed MCF2018 DAS system to see some form of 5G services in the future. Don’t be fooled by the spruikers, we have built systems that are now 4 years old which are actively having 5G deployed on them today (and often they are the boring, not so sexy passive DAS), with no upgrades to the DAS required. This is the beauty of refarming bands
There is lots of misinformation in the industry around 5G having to exclusively be delivered by Small Cells or Active DAS. Small cells will have their place, but will more likely complement an existing DAS and provide hotspots of capacity where the use case suits it, consider food courts or airport lounges. The use of fibre-fed systems should primarily be driven out of necessity, given that the majority of 5G sub 6GHz will be reused 4G spectrum and the new 3800MHz bands the best upgrade path actually comes from having complete wideband support from 700-3800MHz. Active DAS will require the complete swap out or at least the addition of new active hardware with significant associated costs and complexity. If someone is insisting that you need an Active DAS to deploy 5G, there is a good chance they are not fully across the intricacies of the 5G transition and Distributed Antenna Systems (or are just motivated to sell you the solution that makes them the best commission)
The important piece to note is that 5G DAS is an operator-driven rollout program right now and like all technology changes, the initial priority is the outdoor network. There are still plenty of buildings today without dedicated 4G DAS coverage (or even 3G Coverage) where tenants can’t even make phone calls. It’s incredible the amount of throughput that can be delivered on a 4G DAS today, which begs the question, what will we need 5G DAS for in the short-term future.
There are not many tangible use cases today for increased 5G DAS 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”.
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