Self-Organising Networks (SON) has been an integral feature of successful small cell deployments, providing rapid self-configuration, on-going optimisation and self-healing in case of outages. It’s maturing, with significant funds raised by independent SON vendors and interworking plugfests being organised by ETSI. We spoke to two independent SON vendors with contrasting approaches to learn about their assessment of the market and how it affects small cell take-up.
Independent SON vendors expanding
Cellwize, an independent SON vendor, have raised $24 million and employ well over 100 people (up from 60 the previous year). They’ve expanded their customer base to include 10 European operators in the Telefonica group, while growing presence in Russia and becoming established in APAC.
Their centralised SON (C-SON) takes data feeds from multiple sources and then configures the radio network by provisioning parameters for each cellsite. This is more of a graceful orchestration, continuously optimising and refining system operation. It interworks with pretty much any RAN vendor, macro or small cell. The manage both 3G and LTE including inter-RAT handovers. They can either interwork/complement D-SON (Distributed SON) systems or allow deactivation/disabling of D-SON by driving all of the configuration. They've found that some network operators are saying they can't easily work with multiple D-SONs and need a single SON solution.
They are very proud to be an independent SON vendor and have no hidden agenda to sell radio equipment, small cells etc. Cellwize expects to see customer centricity as a major theme. Their current goal is to look at vertical subscriber segments rather than individuals, and optimise for those.
One case study is commuters, where a couple of years ago they would talk about optimisation by system or deployment of more vendor equipment. They are now talking about the door-to-door journey, looking at how to switch between VoLTE/3G/2G at different phases of a commute. They determine which subscriber devices are on a commute versus those just walking down the street or inside buildings. While network performance in an area can appear good overall (say 0.2% call drop rate or less), they sometimes found 4-5% drop rates at peak times for specific customer segments before optimisation.
At the end of the day, customers don’t particularly mind (or even realise) which radio technology carries their voice call (2G/3G/4G) - they just want to ensure a seamless voice call with high continuity and reliability.
Joe Thorne, Senior Director Product Marketing, explained how AirHop has been closely involved with Small Cell SON for many years. He’s one of the Small Cell Forum champions leading their work on the topic. AirHop take a more embedded approach, installing a software client in different vendor’s small cells. They’ve worked closely with market leaders such as Radisys and Broadcom to become part of their reference design, and are integrated into Airspan and Arcadyan small cell products through their eSONify partner program.
He points out that interference management requires a much faster SON configuration, with parameters updated every 200ms. This requires SON client software running in the small cell which co-ordinates with a central server, combining both D-SON (Distributed SON) and C-SON (Centralised CON) aspects. They can also use the X.2 interface or operate via the EMS (Element Management System) if that’s impractical.
They are focussing on LTE today, having invested in 3G in the past but found fewer market opportunities. There are more standardised SON features and parameters built into the LTE standard, opening up more opportunities for optimisation and co-ordination. Their roadmap includes co-ordination between LTE and Wi-Fi.
Their eSOC360 is an umbrella product with three components: A real-time co-ordinated SON, comprehensive visualisation and non-real-time big data analytics.
As an aside, Joe noted a lot more activity around residential Femtocells lately, and believes there are some large scale deployments in the pipeline.
Focus has moved onto LTE rather than 3G
I’d observe that we are seeing much more emphasis and investment for LTE products than 3G today, which may be seen as somewhat of a legacy technology.
However, we’ve noted before that “Peak 3G” is still some years off (i.e the largest proportion of users will be on 3G worldwide in 2020). Vendors with dual-mode 3G/LTE products remain in the minority but have competitive advantage today. Not all networks will adopt VoLTE in the near future, and some will retain 3G using CSFB for all voice calls indefinitely.
However LTE does have many more open and standardised features for SON, interworking through the X.2 interface and inherently designed for multi-vendor interoperability.
Small Cell Forum
One of the Forum’s work programs in progress at the moment relates to SON interoperability. Network operators expect not to rely on a single vendor throughout, and want to ensure that different SON vendors can operate effectively alongside each other. This includes both interaction from top to bottom (C-SON and D-SON), between macro and small cell layers as well as between neighbouring cells from different vendors.
We can expect a published document from the Small Cell Forum in due course. More visible activity comes in the form of a Plugfest in Italy during July 2016, organised by ETSI, at which a number of SON vendors will test interoperability between systems and products.
Moving from Seamless Handover to System Optimisation
Configuring networks to enable seamless handover between small cells and macrocells from different vendors was an early step in small cell evolution.
Optimising performance has been another. This next step will ensure that optimisation operates effectively in multi-vendor environments, reducing risk and concern when introducing new vendors into the radio network.
It should also help improve your experience on the way into work, regardless of the transport taken for your commute. Smarter algorithms, closer interworking and co-operation will all continue to enhance our lives.