There are commonly thought to be three different ways to densify wireless traffic capacity. Perhaps now there is a fourth, which involves orchestrating much better use of the complex variety of spectrum bands, modes and layers. SON vendors would lay first claim to this aspect and promise substantial improvements. Several small cell solution vendors offer gateways and controllers to co-ordinate and manage each radio access technology. The new term of HetNet gateway effectively combines both cellular and Wi-Fi into one box, bridging and consolidating the best of both.
The three four methods of wireless densification
The three main densification methods to increase capacity in a given area:
- Add spectrum: It’s expensive and limited but allows existing cellsites to be quickly expanded providing smartphones support the new frequencies.
- Use spectrum more efficiently: Refarming from 2G to 3G or LTE and using sophisticated techniques like eICIC and CoMP.
- Reuse spectrum by deploying small cells. By far the most dramatic increase and compatible with existing smartphones and devices.
We’ve also seen many operators take advantage of Wi-Fi to offload traffic, effectively adding spectrum. Most of this is unseen. Some would like to “onload” that traffic back to cellular where they have capacity (and can charge for it). Others want to exploit Wi-Fi by offering Carrier grade service through their own and/or partner networks.
Concurrent use of both Wi-Fi and Cellular can be complex and difficult to manage. How do you decide which to use in any particular scenario? How do you ensure seamless handoff between RAN and Wi-Fi, especially when streaming or on a voice call? How do you take advantage of more capable devices while still supporting those with more limited radio technologies and frequency bands?
So there is a fourth aspect which can deliver significant additional benefit:
- HetNet Orchestration: Actively managing all of the resources available to combine both cellular and RAN access technologies into a single, seamless solution.
A HetNet gateway combines the functions of a small cell gateway for 2G, 3G and LTE with the similar gateways used in Wi-Fi. Traffic can be shaped and steered between available radio technologies. SON (Self Organising Network) functions configure and optimise RAN performance, encouraging handoffs where and when required. It promises a relatively quick and large return on investment.
LTE needs a RAN Gateway
2G and 3G RAN architectures had basestation controllers (called the RNC in 3G), and femtocell gateways for small cells. LTE was originally designed without one, causing issues by overloading the core network with signalling traffic. Larger enterprise and residential LTE small cell networks have re-introduced a gateway, consolidating signalling traffic and optimising call drop rates. SK Telecom even added some SON functionality there too.
Larger enterprise small cell products have also used a central controller, effectively a gateway within the building. Solutions from Spidercloud and Airvana differ in architecture but both consolidate the traffic and reduce the signalling overhead for both smartphones and core networks.
LTE macrocell networks don’t use a gateway today, instead directly connecting with the LTE Core Network (EPC).
So what’s a HetNet Gateway?
Parallel Wireless have developed a gateway that handles not just 3G and LTE but also fully integrates Wi-Fi as well. This can scale to handle all of the RAN traffic, both small and macro cell. It also carries both trusted (ie Carrier) and untrusted (e.g. 3rd party residential) Wi-Fi are supported rather than being routed through a parallel and independent set of gateways. This means there is now a single point of real-time control across all wireless access technologies.
It’s an ambitious and radical approach, making use of the latest software architecture techniques to scale efficiently and cost effectively.
Conclusion
Predicting the future isn’t easy. Perhaps the greatest challenge for any CTO is not to determine what mix of RF technology or App will make the greatest demands on their network in time to come. Instead, it’s about shaping their organisation and operation to be in the best position to move quickly and adapt efficiently when the industry does finally make its choice.
While we’ve seen new frequencies and capabilities enabled by LTE take up the majority of investment in recent year, we can expect to see more emphasis on network densification through small cells, C-RAN and Wi-Fi in the near future. Commercial disruption through increased RAN sharing, roaming and new vendor equipment is also likely if unpredictable.
The best-positioned organisations will be those who put in place the capabilities to be agile, adaptable to meet future unknown and unpredictable market demands. HetNet Orchestration provides the flexibility to make the most of all the technologies brought to bear. Capabilities to rapidly deploy integrate, manage and optimise networks will be critical and a holistic approach which deals with all technologies in a co-ordinated manner will have a tremendous advantage.
We've just published a new White Paper which discusses this topic in more detail entitled "Hetnet Orchestration: The Fourth Dimension for Wireless Capacity Growth". Click here to view on SlideShare
Disclaimer: Parallel Wireless are a sponsor of ThinkSmallCell
