Paul Bruce, Director of Business Development at Node-H, argues that small cell developers need to reduce barriers to adoption in order for the industry to fulfil its potential. He points to a Small Cell Forum initiative around SON (Self Organising Networks) as an example that demonstrates how the industry can cooperate to create a real multi-vendor marketplace.
A quick recap of Node-H
Node-H is an independent small cell software specialist, not tied to a single product or silicon provider. Our solution is comprehensive, including all the software you need on a small cell, not just a protocol stack, but security, SON (Self Organising Network), device management, configuration, diagnostic tools, emulators and so on. We ensure the full solution works to a high quality with no need for any additional development effort by the licensee. Node-H products available today support residential and enterprise; UMTS and LTE; FDD and TDD on a range of ecosystem hardware platforms. Recently we introduced a dual-mode LTE+UMTS solution supporting 32 + 32 users.
Node-H's flagship deployment is with Iliad's Free Mobile network in France, with what is believed to be the largest small cell deployment of residential femtocells live today. We worked closely in creating the mobile module for the Freebox home gateway to radically reduce the incremental cost of the built-in femtocell technology. A major milestone was reached when the cost allowed Free Mobile to integrate this as standard for every new customer.
Why is SON so important?
While it’s easy to focus on unit hardware cost, it’s really total lifecycle cost including operational aspects that matters most. For mass-market products that are self-installed intelligent SON software is needed to configure, optimise and self-heal the system. With potentially many millions of cells, an operator can’t afford to sustain large numbers of support calls, device returns or offer a poor user experience.
A further benefit is that traffic that would otherwise be carried on the macrocellular network can be more aggressively moved to the femtocell layer without degrading the quality of experience - if deployed by an MVNO operator it means a material cost reduction in MVNO fees.- if deployed by a macrocell operator it means greater network capacity.
A sophisticated distributed-SON capability sets parameters dynamically to suit each cell's local environment. Critically its distributed nature ensures rapid adaptation to the environment without the scalability concerns of a centralised approach.
How does LTE compare to UMTS in this respect?
Relatively few vendors offer both UMTS and LTE small cells today; even fewer have truly combined multi-mode products. Eventually the industry will transition to LTE-only, but until VoLTE capable handsets are ubiquitous (and international roaming is supported) most operators will continue to be highly dependent on 3G for voice and 4G for data.
The difficulty for the industry today is that few operators will want to invest heavily in 3G technology when LTE is clearly the future. The fact is that we probably haven't yet reached 'peak-3G' in terms of handsets (see ThinkSmallCell's Network Statistics 2016). Multi-mode small cells are a cost efficient way of provisioning focused high quality coverage and capacity for the next few years. However the requirement and timescale will vary considerably by region and by network operator.
It is worth pointing out that a 3G Small Cell gateway is much more complex than its LTE equivalent. It has to handle protocol conversion between Iu-h and Iu, managing and co-ordinating each device. In contrast a LTE gateway is more of an aggregator, although this could include features for traffic management, load balancing etc.
SON also operates quite differently in LTE compared to UMTS. For example with LTE the X2 interface allows communication between cells and network layers that can further refine the SON operation. Although less talked about, SON and RRM are also essential features of UMTS small cells, and without them a wide-scale deployment is simply not possible.
What is being done to ensure LTE SON works properly?
While 3GPP standards describe the basic mechanics used in implementing SON features they do not define the algorithms that should be applied. This facilitates innovation however it also means that different vendors' SON offerings may not be compatible. Worse than being sub-optimal, a mixed-vendor SON enabled network could be unstable or in extreme cases not work at all. This can create an unnecessary barrier to adoption in the industry.
A recent initiative within the Small Cell Forum aims to remove this barrier, making small cells easier to adopt. By identifying the important SON features and then defining a common test specification it means independently developed SON implementations can be compatible. Features include self configuration, inter-cell interference mitigation (similar to ICIC), self healing and power/frequency selection. Node-H now offers a SCF SON compliant implementation and will be participating at the ETSI PlugFest planned for June/July in Naples. It is just another step on our mission to make small cells easier to adopt.
Node-H will be running the SON seminar at the upcoming SCWS World event in London next month, where we will describe the functionality and interworking in greater detail.